Negative Pressure Wound Therapy
Number: 0334
Table Of Contents
PolicyApplicable CPT / HCPCS / ICD-10 Codes
Background
References
Policy
Scope of Policy
This Clinical Policy Bulletin addresses negative pressure wound therapy.
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Medical Necessity
Aetna considers negative pressure wound therapy (NPWT) pumps medically necessary, when either of the following criteria (A or B) is met:
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Ulcers and Wounds in the Home Setting
The member has a chronic Stage III or IV pressure ulcer (see Appendix below), neuropathic ulcer (e.g., diabetic ulcer), venous or arterial insufficiency ulcer, or a chronic ulcer of mixed etiology, present for at least 30 days. A complete wound therapy program described by criterion 1 and criteria 2, 3, or 4 below, as applicable depending on the type of wound, has been tried or considered and ruled out prior to application of NPWT.
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General measures of wound therapy program
For all ulcers or wounds, the following components of a wound therapy program must include a minimum of all of the following general measures, which should either be addressed, applied, or considered and ruled out prior to application of NPWT:
- Application of dressings to maintain a moist wound environment, and
- Debridement of necrotic tissue if present, and
- Documentation of evaluation, care, and wound measurements by a licensed medical professional, and
- Evaluation of and provision for adequate nutritional status.
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For Stage III or IV pressure ulcers
- The member has been appropriately turned and positioned, and
- The member has used a group 2 or 3 support surface for pressure ulcers on the posterior trunk or pelvis (see CPB 0430 - Pressure Reducing Support Surfaces) Note: A group 2 or 3 support surface is not required if the ulcer is not on the trunk or pelvis; and
- The member's moisture and incontinence have been appropriately managed.
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For neuropathic (e.g., diabetic) ulcers
- The member has been on a comprehensive diabetic management program, and
- Reduction in pressure on a foot ulcer has been accomplished with appropriate modalities.
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For venous insufficiency ulcers
- Compression bandages and/or garments have been consistently applied, and
- Leg elevation and ambulation have been encouraged.
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Ulcers and Wounds Encountered in an Inpatient Setting
- An ulcer or wound (described in Section A above) is encountered in the inpatient setting and, after wound treatments described in Sections A.1 through A.4 for the various types of ulcers above have been tried or considered and ruled out, it is necessary to initiate NPWT.
- The member has complications of a surgically created wound (e.g., dehiscence) or a traumatic wound (e.g., pre-operative flap or graft) where there is documentation of the medical necessity for accelerated formation of granulation tissue which can not be achieved by other available topical wound treatments (e.g., other conditions of the member that will not allow for healing times achievable with other topical wound treatments).
- Management of fasciotomy wounds in persons with compartment syndrome.
In either situation for Section B.1 or B.2, NPWT will be considered medically necessary when treatment continuation is ordered beyond discharge to the home setting.
Note: NPWT pumps must be capable of accommodating more than 1 wound dressing set for multiple wounds on a member. Therefore, more than 1 NPWT pump billed per member for the same time period is considered not medically necessary. See specifications of equipment and supplies in the Appendix.
Note: NPWT is usually administered once-weekly.
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Contraindications
An NPWT pump and supplies is considered not medically necessary if one or more of the following contraindications are present:
- The presence in the wound of necrotic tissue with eschar, if debridement is not attempted; or
- Osteomyelitis within the vicinity of the wound that is not concurrently being treated with intent to cure; or
- Cancer present in the wound; or
- The presence of an open fistula to an organ or body cavity within the vicinity of the wound.
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Continued Medical Necessity
For wounds and ulcers described in Sections I and II above, once placed on an NPWT pump and supplies, in order to document continued medical necessity, a licensed medical professional must do the following:
- On a regular basis, directly assess the wound(s) being treated with the NPWT pump, and supervise or directly perform the NPWT dressing changes, and
- On at least a monthly basis, document changes in the ulcer's dimensions and characteristics.
Note: Once-weekly NPWT is considered medically necessary.
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Discontinuation Criteria
For wounds and ulcers described in Sections A and B above, an NPWT pump and supplies will be considered as not medically necessary with any of the following, whichever occurs earliest:
- Any measurable degree of wound healing has failed to occur over the prior month. Wound healing is defined as improvement occurring in either surface area (length times width) or depth of the wound. There must be documentation of quantitative measurements of wound characteristics including wound length and width (surface area), or depth, serially observed and documented, over a specified time interval. The recorded wound measurements must be consistently and regularly updated and must have demonstrated progressive wound healing from month to month; or
- Four months (including the time NPWT was applied in an inpatient setting prior to discharge to the home) have elapsed using an NPWT pump in the treatment of any wound. The medical necessity of NPWT beyond 4 months will be given individual consideration based upon required additional documentation; or
- In the judgment of the treating physician, adequate wound healing has occurred to the degree that NPWT may be discontinued, or
- Once equipment or supplies are no longer being used for the member, whether or not by the physician's order; or
- When criteria under Section on Continued Medical Necessity above, cease to be met.
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Supplies
- Up to a maximum of 15 dressing kits per wound per month is considered medically necessary unless there is documentation that the wound size requires more than 1 dressing kit for each dressing change.
- Up to a maximum of 10 canister sets per month is considered medically necessary unless there is documentation showing a large volume of drainage (greater than 90 ml of exudate per day). For high volume exudative wounds, a stationary pump with the largest capacity canister must be used. Excess utilization of canisters related to equipment failure (as opposed to excessive volume drainage) is not considered medically necessary.
See specifications of equipment and supplies in the Appendix.
Note: Staging of pressure ulcers used in this policy is as follows:
Table: Stages of pressure ulcers Stages Description Suspected Deep Tissue Injury Purple or maroon localized are of discolored intact skin or blood-filled blister due to damage of underlying soft tissue from pressure and/or shear. The area may be preceded by tissue that is painful, firm, mushy, boggy, warmer or cooler as compared to adjacent tissue. Stage I Intact skin with non-blanchable redness of a localized area usually over a bony prominence. Darkly pigmented skin may not have visible blancing; its color may differ from the surrounding area. Stage II
Partial thickness loss of dermis presenting as a shallow open ulcer with red or pink wound bed, without slough. May also present as an intact or open/ruptured serum-filled blister. Stage III
Full thickness tissue loss. Subcutaneous fat may be visible but bone, tendon or muscle are not exposed. Slough may be present but does not obscure the depth of tissue loss. May include undermining or tunneling. Stage IV Full thickness tissue loss with exposed bone, tendon or muscle. Slough or eschar may be present on some parts of the wound bed. Often include undermining and tunneling. Unstageable Full thickness tissue loss in which the base of the ulcer is covered by slough (yellow, tan, gray, green or brown) and/or eschar (tan, brown, or black) in the wound bed. -
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Experimental and Investigational
The following procedures are considered experimental and investigational because the effectiveness of these approaches has not been established:
- Chemotherapeutic agents (e.g. doxycycline and insulin) in continuous-instillation or intermittent-instillation negative pressure wound therapy (NPWT);
- Non-powered (mechanical) NPWT devices (e.g., the Smart Negative Pressure [SNaP] Wound Care System);
- Single-use NPWT devices (e.g., PICO Single Use Negative Pressure Wound Therapy System; Prevena Incision Management System) for all indications (e.g., keloid scarring, wound care including management of closed sternal incision following thoracic artery grafting, management of wound sites following mammoplasty, and prophylaxis after lower extremity fracture surgery). Note: Single-use NPWT devices are not covered under plans that exclude coverage of supplies; please check benefit plan descriptions;
- VeraFlo (an intermittent instillation wound vacuum) for wound healing (including diabetic foot ulcer);
- Wound Vac for the treatment of full thickness burns;
- NPWT for the following indications (not an all-inclusive list):
- For use following cardiac surgery (e.g., internal thoracic artery grafting) not meeting criteria above
- For use following knee arthroplasty not meeting criteria above
- For use following surgical excision of pilonidal sinus disease and for recurrent pilonidal disease
- For use following total joint (e.g., hip and knee) arthroplasty
- For use in donor-site closure in radial forearm free flap
- For use in fingertip replantation
- For use in fracture-related infections following internal osteosynthesis of the extremity
- For use in head and neck free flap reconstruction not meeting medical necessity criteria above
- For use in head and neck wounds with fistulas
- For use in kidney transplantation in recipients not meeting criteria above
- For use in open fracture / traumatic wounds
- For use in vascular surgery (including closed groin incisions in arterial surgery, and infra-inguinal re-vascularization with a groin incision)
- Prevention and management of complications from prosthetic breast reconstruction
- Prevention of complications in surgical wounds of the abdomen based upon presence of diabetes or obesity as risk factors
- Prophylactic use in uncomplicated abdominal surgical wounds for the prevention of surgical site infection
- Prophylactic use after cesarean delivery
- Prophylactic use after ventral hernia repairs
- Prophylactic use on surgical site infections in pancreatic resection
- Treatment of deep sternal wound infection, partial-thickness burns, tibial fractures;
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Closed incision NPWT (ciNPWT) for the following indications because the effectiveness of this approach has not been established:
1. prevention of surgical site infections or wound dehiscence after spinal fusion; or
2. preventon of surgical site infections or wound dishiscence after primary total joint arthroplasty.
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Policy Limitations and Exclusions
Negative pressure wound therapy applied prophylactically for surgical care is considered incidental to the surgery and not separately reimbursed.
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Related Policies
Background
This policy is based in part upon Medicare DME MAC medical necessity criteria for negative pressure wound therapy (NPWT) pumps.
Negative pressure wound therapy is the controlled application of subatmospheric pressure to a wound using an electrical pump to intermittently or continuously convey subatmospheric pressure through connecting tubing to a specialized wound dressing which includes a resilient, open-cell foam surface dressing, sealed with an occlusive dressing that is meant to contain the subatmospheric pressure at the wound site and thereby promote wound healing. Drainage from the wound is collected in a canister.
Negative pressure wound therapy has been used to promote healing of chronic wounds and pressure ulcers (decubitus ulcers) by creating controlled negative pressure over the wound that is thought to increase local vascularity and oxygenation of the wound bed, reduce edema by evacuating wound fluid, and remove exudate and bacteria.
More than a dozen systematic evidence reviews produced by independent organizations have questioned the quality of the evidence supporting the use of NPWT, including systematic evidence reviews published by the Cochrane Collaboration (Evans and Land, 2001; Wasiak and Cleland, 2007; Ubbink et al, 2008), Washington State Department of Labor and Industries (2003), Canadian Coordinating Office for Health Technology Assessment (Fisher and Brady, 2003), Australian Safety and Efficacy Register of New Interventional Procedures – Surgical (Pham et al, 2003), NHS Quality Improvement Scotland (NHS QIS, 2003), Centre for Clinical Effectiveness (Higgins, 2003), Agency for Healthcare Research and Quality (Samson et al, 2004), Technology Assessment Unit of McGill University Health Centre (Costa et al, 2005), Institute for Quality and Efficiency in Health Care (IQWiG, 2006), Ontario Ministry of Health and Long-Term Care (MAS, 2004; MAS, 2006), Galician Agency for Health Technology Assessment (AVALIA-T, 2005), and BMJ Clinical Evidence (Nelson and Jones, 2006; Nelson and Penthrick, 2007).
Control of intra-abdominal fluid secretion, facilitation of abdominal exploration, and preservation of the fascia for abdominal wall closure is a major challenge in the management of patients with an open abdomen. Vacuum-assisted therapy has been reported to help meet the challenges of managing the open abdomen and may be useful in patients with abdominal compartment syndromes, traumatic injuries, and severe intra-abdominal sepsis. In a review on the management of patients with open abdomen, Kaplan (2004) concluded that controlled clinical studies are needed to establish the safety and effectiveness of this treatment approach and to facilitate the development of treatment guidelines to help manage an increasingly common group of patients who might benefit from this treatment approach. A systematic evidence review by the National Institute for Health and Clinical Excellence (NICE, 2009) found inadequate evidence for the use of NPWT in open abdominal wounds. The NICE assessment concluded that "[c]urrent evidence on the safety and efficacy of negative pressure wound therapy (NPWT) for the open abdomen is inadequate in quality and quantity. There has been concern about the occurrence of intestinal fistulae associated with this procedure but there is currently no evidence about whether NPWT is the cause."
Schimmer and colleagues (2007) stated that there are many primary modalities for managing deep sternal wound infection (DSWI) following cardiac surgery, namely surgical debridement with primary re-closure in conjunction with irrigation, vacuum-assisted closure (VAC), and primary or delayed flap closure. These researchers examined if there is consensus on the primary management of DSWI using one method as a single line therapy or a combination of these procedures. Therefore, a questionnaire with regards to the primary treatment modalities of DSWI was distributed to all 79 German heart surgery centers. All replied to the questionnaire – VAC is used in 28/79 (35 %) heart centers as the 'first-line' treatment, 22/79 (28 %) perform primary reclosure in conjunction with a double-tube irrigation/suction system, and in 29/79 (37 %) clinics both treatment options were used according to intra-operative conditions. Mostly, as a primary management of DSWI two treatment modalities are mainly in use: primary reclosure coupled with a double-tube suction/irrigation system and VAC. The current understanding is based purely on retrospective studies, not evidence-based medicine. Since prospective randomized controlled trials (RCTs) have not yet been performed, controlled clinical trials comparing these treatment modalities are pivotal to define evidence for patients presenting with DSWI.
Morris et al (2007) noted that although NPWT appears effective, it remains unknown if it is more effective than other wound closure techniques. In addition, although many uncontrolled, non-randomized studies describing the effectiveness of this therapy have been published, few prospective RCTs have been conducted. Small sample sizes, variable outcome measures across studies, and significant methodological problems in the available RCTs further limit the conclusions that can be drawn regarding the relative effectiveness of vacuum-assisted wound closure. Analysis of these data provided weak evidence to suggest that NPWT is superior to saline gauze dressings in healing chronic wounds. The authors concluded that RCTs comparing healing, costs of care, patient pain, and quality-of-life outcomes of this treatment to non-gauze type dressings and other treatment modalities are needed.
Gregor et al (2008) examined the clinical effectiveness and safety of negative NPWT compared with conventional wound therapy; RCTs and non-RCTs comparing NPWT and conventional therapy for acute or chronic wounds were included in this review. The main outcomes of interest were wound-healing variables. After screening 255 full-text articles, 17 studies remained. In addition, 19 unpublished trials were found, of which 5 had been prematurely terminated. Two reviewers independently extracted data and assessed methodological quality in a standardized manner. Seven RCTs (n = 324) and 10 non-RCTs (n = 278) met the inclusion criteria. The overall methodological quality of the trials was poor. Significant differences in favor of NPWT for time to wound closure or incidence of wound closure were shown in 2 of 5 RCTs and 2 of 4 non-RCTs. A meta-analysis of changes in wound size that included 4 RCTs and 2 non-RCTs favored NPWT (standardized mean difference: RCTs, -0.57; non-RCTs, -1.30). The authors concluded that although there is some indication that NPWT may improve wound healing, the body of evidence available is insufficient to clearly prove an additional clinical benefit of NPWT. Furthermore, the large number of prematurely terminated and unpublished trials is reason for concern.
Vikatmaa et al (2008) conducted a systematic review of the literature on the safety and effectiveness of NPWT for problematic wounds. A total of 14 RCTs were included. Trials included patients with:- pressure wounds,
- post-traumatic wounds,
- diabetic foot ulcers, and
- miscellaneous chronic ulcers. Only 2 trials were classified as high quality studies, whereas the remaining were classified as having poor internal validity.
The authors concluded that
- reliable evidence on the effectiveness of NPWT is scarce,
- tentative evidence indicates that the effectiveness of NPWT is at least as good as or better than current local treatment for wounds, and
- the need for large high-quality randomized studies is apparent.
Blume et al (2008) evaluated the safety and clinical efficacy of NPWT compared with advanced moist wound therapy (AMWT) (predominately hydrogels and alginates) to treat foot ulcers in diabetic patients in a multi-center randomized controlled trial (n = 342). The mean age was 58 years and 79 % of subjects were male. Complete ulcer closure was defined as skin closure (100 % re-epithelization) without drainage or dressing requirements. Patients were randomly assigned to either NPWT or AMWT (predominately hydrogels and alginates) and received standard off-loading therapy as needed. The trial evaluated treatment until day 112 or ulcer closure by any means. Patients whose wounds achieved ulcer closure were followed at 3 and 9 months. Each study visit included closure assessment by wound examination and tracings. A greater proportion of foot ulcers achieved complete ulcer closure with NPWT (73 of 169, 43.2 %) than with AMWT (48 of 166, 28.9 %) within the 112-day active treatment phase (p = 0.007). The Kaplan-Meier median estimate for 100 % ulcer closure was 96 days (95 % confidence interval [CI]: 75.0 to 114.0) for NPWT and not determinable for AMWT (p = 0.001). Patients who received NPWT experienced significantly (p = 0.035) fewer secondary amputations. The proportion of home care therapy days to total therapy days for NPWT was 9,471 of 10,579 (89.5 %) and 12,210 of 12,810 (95.3 %) for AMWT. In assessing safety, no significant difference between the groups was observed in treatment-related complications such as infection, cellulitis, and osteomyelitis at 6 months. The authors concluded that NPWT appears to be as safe as and more efficacious than AMWT for the treatment of diabetic foot ulcers.
A technology assessment report on NPWT (Sullivan et al, 2009) prepared for the Agency for Healthcare Research and Quality found that systematic reviews of NPWT reveal the following important points about the current state of the evidence on this technology:- all of the systematic reviews noted the lack of high-quality clinical evidence supporting the advantages of NPWT compared to other wound treatments; the lack of high-quality NPWT evidence resulted in many systematic reviewers relying on low-quality retrospective studies to judge the efficacy of this technology,
- no studies directly comparing different NPWT components (e.g., foam versus gauze dressings) were identified by any of the reviewers, and
- NPWT must be evaluated according to wound type; wound healing varies according to the type of wound being treated and NPWT benefits described for one wound type cannot be assumed to apply to other wound types.
The assessment stated that the available evidence cannot be used to determine a significant therapeutic distinction of a NPWT system. In addition, due to the lack of studies comparing one NPWT system to another NPWT system the severity of adverse events for 1 NPWT system compared to another could not be determined. The report concluded, "Clinical research on NPWT capable of indicating if any one NPWT system or component provides a significant therapeutic distinction requires study design and conduct that will minimize the possibilities for bias. Important study design features that were not typically reported such as concealment of allocation, reporting of randomization methods, use of power analysis to ensure adequate study size, blinding wound assessors, and reporting of complete wound healing data will improve the internal validity and the informativeness of the studies."
More recently, the Johns Hopkins University Evidence-based Practice Center prepared a comprehensive technology assessment for the Agency for Healthcare Research and Quality (AHRQ) on the effectiveness of negative pressure wound therapy (NPWT) on the treatment of chronic wounds in the home care setting (Rhee et al, 2014). The goal of the assessment was to systematically review the efficacy and safety of NPWT for treatment of chronic wounds in the home setting. The authors included studies examining the use of NPWT in patients with chronic wounds, including venous leg ulcers, arterial leg ulcers, diabetic foot ulcers, pressure ulcers, and mixed etiology chronic wounds. They retrieved 5,912 citations, and found seven studies which met the criteria for inclusion. Six of the studies compared NPWT devices to other wound care methods. One study compared two different NPWT devices. Ultimately the assessment's authors were unable to draw any firm conclusions about the efficacy or safety of NPWT for the treatment of chronic wounds in the home setting due to insufficient evidence. The authors stated "Though NPWT has been used across the wound care spectrum, significant research gaps remain. Standardization of wound care research protocols, such as providing consistency in comparator groups, robust randomized study designs, larger trials, and common definitions of outcomes, would be helpful in providing evidence to inform decisions about the use of NPWT."
Negative pressure wound therapy uses a reticulated sponge and subatmospheric pressure to facilitate healing of a variety of wounds. The therapy appears to assist wound healing by decreasing wound bacterial burden and edema while facilitating granulation tissue formation. The latest development in NPWT allows clinicians to instill continuously a treatment solution and suspension into the wound. A variety of wound chemo-therapeutic agents such as insulin, which acts as a growth factor, may prove helpful in this aspect. Scimeca and colleagues (2010a) presented a case report in which insulin was used as a chemo-therapeutic agent in continuous-instillation NPWT. To the authors' knowledge, this is the first report in the literature describing this method of delivery. Furthermore, Scimeca et al (2010b) described a real-time streaming therapy of a variety of wound chemo-therapeutic agents through NPWT. Doxycycline, which acts as a competitive inhibitor of matrix metalloproteinases and tumor necrosis factor alpha and further decreases inflammation through the reduction of nitrous oxide production, may prove helpful when delivered in this manner. To the authors' knowledge, this is the first report in the literature describing this method of delivery of doxycycline. The clinical value of chemo-therapeutic agents in continuous-instillation NPWT nees to be ascertained in randomized, controlled clinical trials.
A non-powered (mechanical) NPWT device, the Smart Negative Pressure (SNaP) Wound Care System from Spiracur, is a class II device that received 510(k) marketing clearance from the Food and Drug Administration in 2010 and is designed to remove small amounts of exudate from chronic, traumatic, dehisced, acute, subacute wounds and diabetic and pressure ulcers. The lack of well-designed comparative studies with large number of individuals using the non-powered NPWT system is insufficient to draw conclusions about its impact on health outcomes with the device and in comparison with current care.
Armstrong et al (2012) compared the portable mechanically powered Smart Negative Pressure (SNaP) Wound Care System (Spiracur, Sunnyvale, CA) with the electrically powered VAC Therapy System (Kinetic Concepts, Inc. [KCI], San Antonio, TX) in a multicenter, comparative efficacy, noninferiority-powered, randomized controlled trial. Investigators enrolled 132 people with noninfected, nonischemic, nonplantar lower extremity diabetic and venous wounds. Each subject was randomly assigned (1:1) to treatment with either system in conjunction with appropriate off-loading and compression therapy. The trial evaluated treatment for up to 16 weeks or complete wound closure (defined as complete reepithelialization without drainage). Primary end point analysis of wound size reduction found that SNaP-treated subjects demonstrated noninferiority to the VAC-treated subjects at 4, 8, 12, and 16 weeks (p = 0.0030, 0.0130, 0.0051, and 0.0044, respectively). Kaplan-Meier analysis showed no significant difference in complete wound closure between SNaP- and VAC-treated subjects at all time points. Device related adverse events and complications such as infection were also similar between treatment groups. An AHRQ assessment (Rhee et al, 2014) noted study limitations including lack of blinding, imbalanced study groups particularly in terms of wound size, and lack of reporting of intervention details. The ARHQ assessment downgraded study limitations to “high” for the outcome of pain because of limited reporting of statistical details. All of the outcomes were direct, but the results were imprecise. The AHRQ assessment stated that they were unable to assess consistency or reporting bias. The AHRQ assessment noted that the study was funded by the manufacturer of one of the devices (SNaP) and two of the investigators reported receiving funding from manufacturers of both devices being evaluated.
The European Pressure Ulcer Advisory Panel's clinical practice guideline on pressure ulcer treatment (2009) recommended conventional NPWT therapy, but did not mention non-powered NPWT.
In a systematic review, Roberts et al (2012) determined the comparative safety and effectiveness of NPWT versus alternate temporary abdominal closure (TAC) techniques in critically ill adults with open abdominal wounds. These researchers reviewed published and unpublished comparative studies. They searched MEDLINE, PubMed, EMBASE, Scopus, Web of Science, the Cochrane Database, the Center for Reviews and Dissemination, clinical trials registries, and bibliographies of included articles. Two authors independently abstracted data on study design, methodological quality, patient characteristics, and outcomes. Among 2,715 citations identified, 2 RCTs and 9 cohort studies (3 prospective/6 retrospective) met inclusion criteria. Methodological quality of included prospective studies was moderate. One RCT observed an improved fascial closure rate (relative risk [RR], 2.4; 95 % CI: 1.0 to 5.3) and length of hospital stay after addition of retention sutured sequential fascial closure to the Kinetic Concepts Inc. (KCI) vacuum-assisted closure (VAC). Another reported a trend toward enhanced fascial closure using the KCI VAC versus Barker's vacuum pack (RR, 2.6; 95 % CI: 0.95 to 7.1). A prospective cohort study observed improved mortality (RR, 0.48; 95 % CI: 0.25 to 0.92) and fascial closure (RR, 1.5; 95 % CI: 1.1 to 2.0) for patients who received the ABThera versus Barker's vacuum pack. Another noted a reduced arterial lactate, intra-abdominal pressure, and hospital stay for those fitted with the KCI VAC versus Bogotá bag. Most included retrospective studies exhibited low methodological quality and reported no mortality or fascial closure benefit for NPWT. The authors concluded that limited prospective comparative data suggested that NPWT versus alternate TAC techniques may be linked with improved outcomes. Moreover, they stated that the clinical heterogeneity and quality of available studies precluded definitive conclusions regarding the preferential use of NPWT over alternate TAC techniques.
Guidance from the National Institute for Health and Clinical Excellence (NICE, 2013) stated that current evidence on the safety and efficacy of NPWT for the open abdomen is adequate to support the use of this procedure provided that normal arrangements are in place for consent, audit and clinical governance. The guidance stated that NPWT for the open abdomen may be used to manage open abdominal wounds in which the gut and other intraperitoneal organs are exposed.
In a Cochrane review, Dumville and Munson (2012) evaluated the effectiveness of NPWT for people with partial-thickness burns. For this third update we searched the Cochrane Wounds Group Specialised Register (searched May 18, 2012); the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2012, Issue 5); Ovid MEDLINE (2010 to week 2 of May 2012); Ovid MEDLINE (in-process & other non-indexed citations May 17, 2012); Ovid EMBASE (2010 to week 19 of 2012); and EBSCO CINAHL (2010 to May 16, 2012). All RCTs and controlled clinical trials (CCTs) that evaluated the safety and effectiveness of NPWT for partial-thickness burns were selected for analysis. Two review authors used standardized forms, and extracted the data independently. They assessed each trial for risk of bias, and resolved differences by discussion. One RCT, that was an interim report, satisfied the inclusion criteria. These investigators undertook a narrative synthesis of results, as the absence of data and poor reporting precluded them from carrying out any formal statistical analysis. The trial was at high-risk of bias. The authors concluded that there was insufficient evidence available to permit any conclusions to be drawn regarding the use of NPWT for treatment of partial-thickness burn wounds.
The PICO single-use negative pressure wound therapy device (Smith & Nephew, Inc., Andover, MA) is a single-use, canister-free, negative pressure wound therapy device. It is marketed for use in the following types of wounds: chronic; acute; traumatic; subacute and dehisced wounds; partial-thickness burns; ulcers (e.g., diabetic or pressure); flaps and grafts; and closed surgical incisions. The PICO system contains a disposable, 1-button pump, coupled with an advanced dressing that negates the need for a canister. The pump is pocket-sized and the dressing can be worn up to 7 days.
Fraccalvieri et al (2013) stated that keloid scarring represents a pathological healing where primary healing phenomenon is deviated from normal. PICO is a single-use negative pressure wound therapy system originally introduced to manage open or just closed wounds. PICO dressing is made of silicone, and distributes an 80 mmHg negative pressure across wound bed. Combination of silicon layer and continuous compression could be a valid method to manage keloid scarring. Since November 2011, 3 patients were enrolled and evaluated before negative pressure treatment, at end of treatment (1 month) and 2 months later, through Vancouver scar scale (VSS), visual analog scale (VAS) and a scoring system for itching. Ultrasound (US) and color-power-Doppler (CPD) examination was performed to evaluate thickness and vascularization of the scar. One patient was discharged from study after 1 week. In last 2 patients, VSS, VAS and itching significantly improved after 1 month therapy and the results were stable after 2 months without any therapy. At end of therapy, the appearance of palisade vessels disappeared in both cases at CPD exam; US showed a thickness reduction (average of 43.8 %). The authors proposed a well-tolerated, non-invasive treatment to manage keloid scarring. They stated that prospective studies are needed to confirm these preliminary findings.
Ousey et al (2013) stated that the management of post-operative spinal wound complication remains a challenge, with surgical site infection (SSI) incidence rates ranging from 0.4 % to 20 % after spinal surgery. Negative pressure wound therapy has been highlighted as an intervention that may stimulate healing and prevent SSI. However, the wound healing mechanism by NPWT and its effectiveness in spinal wounds still remain unclear. These researchers systematically searched, critically appraised, and summarized RCTs and non-RCTs evaluating the effectiveness of NPWT in patients with a spinal wound. A systematic review based on search strategies recommended by the Cochrane Back and Wounds Review Groups was undertaken using Cochrane Library, MEDLINE, EMBASE, and CINAHL databases. Any publications between 1950 and 2011 were included. A total of 10 retrospective studies and 4 case studies of patients with spinal wound complication were included in this systematic review. No RCTs were found; only 1 study described more than 50 patients. Generally, a pressure of -125 mm Hg was used in adults. Duration of NPWT in-situ ranged from 3 to 186 days. Wound healing was assessed every 2 to 3 days and generally completed between 7 days and 16 months. Negative pressure wound therapy is contraindicated in the presence of active cerebrospinal fluid leak, metastatic or neoplastic disease in the wound or in patients with an allergy to the NPWT dressing and in those with a bleeding diathesis. The authors concluded that published reports were limited to small retrospective and case studies, with no reports of NPWT being used as a prophylactic treatment. They stated that larger prospective RCTs of NPWT are needed to support the current evidence that it is effective in treating spinal wound complications. In addition, future studies should investigate its use as a prophylactic treatment to prevent infection and report data relating to safety and health economics.
Karlakki et al (2013) stated that the period of post-operative treatment before surgical wounds are completely closed remains a key window, during which one can apply new technologies that can minimize complications. One such technology is the use of NPWT to manage and accelerate healing of the closed incisional wound (incisional NPWT). These investigators undertook a literature review of this emerging indication to identify evidence within orthopedic surgery and other surgical disciplines. Literature that supports the current understanding of the mechanisms of action was also reviewed in detail. A total of 33 publications were identified, including 9 clinical study reports from orthopedic surgery; 4 from cardiothoracic surgery and 12 from studies in abdominal, plastic and vascular disciplines. Most papers (26 of 33) had been published within the past 3 years. Thus far, 2 RCTs – 1 in orthopedic and 1 in cardiothoracic surgery – showed evidence of reduced incidence of wound healing complications after between 3 and 5 days of post-operative NPWT of 2- and 4-fold, respectively. Investigations showed that reduction in hematoma and seroma, accelerated wound healing and increased clearance of edema are significant mechanisms of action. The authors concluded that there is a rapidly emerging literature on the effect of NPWT on the closed incision. Initiated and confirmed first with a RCT in orthopedic trauma surgery, studies in abdominal, plastic and vascular surgery with high rates of complications have been reported recently. They stated that the evidence from single-use NPWT devices is accumulating. There are no large randomized studies yet in reconstructive joint replacement.
Selvaggi et al (2014) noted that surgical site complications (SSC) negatively affect costs of care and prolong length of stay. Crohn's disease (CD) is a risk factor for SSC; CD patients often need surgery, sometimes requiring stoma. These researchers compared the effects on SSC of a portable device for NPWT (PICO) with gauze dressings after elective surgery for CD. Secondary aims were manageability and safety of PICO and its feasibility as home therapy. Between 2010 and 2012, a total of 50 patients were assigned to treatment with either PICO (n = 25) or conventional dressings (n = 25). Each patient completed 12-month follow-up. Parameters of interests for primary aim were SSC, surgical complications, and re-admission rates. Data on difficulties in managing PICO and device-related complications were also collected. Patients receiving PICO had less SSC, resulting in shorter hospital stay. At last follow-up, re-admission rates were lower with PICO. No differences were observed in surgical complications between groups. No patients reported difficulties in managing the device. Among patients discharged with PICO, none needed to come back to the hospital for device malfunctioning or inability to manage it. PICO reduces SSC and length of stay in selected CD patients compared with conventional dressings. This was a small study (n = 25 for PICO); its findings need to be validated by well-designed studies.
In a Cochrane review, Webster et al (2014) evaluated the effects of NPWT on surgical wounds (primary closure, skin grafting or flap closure) that are expected to heal by primary intention. These investigators searched the following electronic databases to identify reports of relevant RCTs: the Cochrane Wounds Group Specialised Register (searched January 28, 2014); the Cochrane Central Register of Controlled Trials (CENTRAL; 2013, issue 12); Database of Abstracts of Reviews of Effects (2013, issue 12); Ovid MEDLINE (2011 to January 2014); Ovid MEDLINE (In-Process & Other Non-Indexed Citations January 24, 2014); Ovid EMBASE (2011 to Week 44 of January 2014); and EBSCO CINAHL (2011 to January 2014). These researchers conducted a separate search to identify economic evaluations. They included trials if they allocated patients to treatment randomly and compared NPWT with any other type of wound dressing, or compared one type of NPWT with a different type of NPWT. They assessed trials for their appropriateness for inclusion and for their quality. This was done by 3 review authors working independently, using pre-determined inclusion and quality criteria. In this first update, these investigators included an additional 4 trials, taking the total number of trials included to 9 (785 participants) – 3 trials involved skin grafts, 4 included orthopedic patients and 2 included general surgery and trauma surgery patients; all the included trials had unclear or high risk of bias for one or more of the quality indicators we assessed. A total of 7 trials compared NPWT with a standard dressing (2 of these were 'home-made' NPWT devices), 1 trial compared one 'home-made' NPWT with a commercially available device. In trials where the individual was the unit of randomization, there were no differences in the incidence of surgical site infections (SSI); wound dehiscence, re-operation (in incisional wounds); seroma/hematoma; or failed skin grafts. Lower re-operation rates were observed among skin graft patients in the 'home-made' NPWT group (7/65; 10.8 %) compared to the standard dressing group (17/66; 25.8 %) (RR 0.42; 95 % CI: 0.19 to 0.92). The mean cost to supply equipment for VAC® therapy was US$ 96.51/day compared to US$ 4.22/day for one of the 'home-made' devices (p value 0.01); labor costs for dressing changes were similar for both treatments. Pain intensity score was also reported to be lower in the 'home-made' group when compared with the VAC® group (p value 0.02). One of the trials in orthopedic patients was stopped early because of a high incidence of fracture blisters in the NPWT group (15/24; 62.5 %) compared with the standard dressing group (3/36; 8.3 %) (RR 7.50; 95 % CI: 2.43 to 23.14). The authors concluded that the evidence for the effects of NPWT for reducing SSI and wound dehiscence remains unclear, as does the effect of NPWT on time to complete healing. Rates of graft loss may be lower when NPWT is used, but hospital-designed and built products are as effective in this area as commercial applications. There were clear cost benefits when non-commercial systems were used to create the negative pressure required for wound therapy, with no evidence of a negative effect on clinical outcome. In 1 study, pain levels were also rated lower when a 'home-made' system was compared with a commercial counterpart. The high incidence of blisters occurring when NPWT is used following orthopedic surgery suggested that the therapy should be limited until safety in this population is established. They stated that given the cost and widespread use of NPWT, there is an urgent need for suitably powered, high-quality trials to evaluate the effects of the newer NPWT products that are designed for use on clean, closed surgical incisions. Such trials should focus initially on wounds that may be difficult to heal, such as sternal wounds or incisions on obese patients.
Kostaras et al (2014) stated that NPWT has been suggested to have a positive impact on the healing of sternal or extremity wounds. However, few data deriving from breast surgery have been published. These researchers evaluated the available literature regarding the effectiveness of NPWT systems in the healing of breast tissues. The PubMed and Scopus databases were searched systematically, and all studies that provided relevant data were considered eligible for inclusion in the review. A total of 20 studies (154 female patients) met the inclusion criteria (4 cohort studies, 1 case series, and 15 case reports). The NPWT system was used alone in 17 patients and in combination with other techniques in the remaining 137. The lesion was secondary to plastic surgery in 107 women, other operations in 40 women (38 of them for breast cancer), and primary breast infection in 7 women. Infections (including necrotizing fasciitis), pyoderma gangrenosum, and necrosis were among the most common complications for which NPWT was used. In total, 150 of 154 patients receiving NPWT healed completely. Two patients died before complete closure for reasons unrelated to the wound, and NPWT failed in 2 patients who healed later with muscle flap coverage. The authors concluded that the scant published evidence suggested that NPWT systems might be useful in the healing of complicated breast wounds. However, they stated that larger studies are needed to investigate the effectiveness of this system further before it is established in breast surgery.
The literature on the use of NPWT in surgical wounds has focused on its use in wound complications. There is only scant literature on the use of NPWT in preventing complications in surgical wounds of the abdomen based upon presence of diabetes or obesity as risk factors.
In a pilot study, Mark et al (2013) assessed the effectiveness of incisional negative pressure therapy in decreasing post-operative wound complications when placed prophylactically over clean, closed incisions following cesarean section in obese patients. This was a retrospective cohort study comparing rates of wound complications following Cesarean sections in morbidly obese women prior to and following the institution of standard use of prophylactic incisional negative pressure therapy. All women with a body mass index (BMI) greater than 45 kg/m2 undergoing cesarean section in a 2-year period in a single institution were included. The exposure was incisional negative pressure therapy, which began in September 2009, versus standard wound dressing used in the previous year. The main outcome was wound complication identified by ICD-9 codes. Demographic and wound outcomes were compared with χ2 and t tests. Stata version 11.0 was used for all analysis. A total of 63 women met the inclusion criteria, 21 of whom received NPWT. The historical comparison and exposure groups were similar in all characteristics studied with the exceptions of length of surgery (64 versus 76 minutes, p = 0.03), length of labor (78 versus 261 minutes, p = 0.02), scheduled versus non-scheduled (77 % versus 52 %, p = 0.04), and mean age (29.5 versus 26.1 years, p = 0.04), respectively. There were 5 wound complications in the control group (10.4 %) and none (0 %) in the study group (p = 0.15). The authors concluded that the findings of this pilot study suggested a decrease in wound complications in morbidly obese women receiving incisional negative pressure therapy following Cesarean section. The main drawbacks of this study were its retrospective nature and its small sample size (n = 21 for women receiving NPWT). These preliminary findings need to be validated by well-designed studies.
- Does the use of NPWT compared with gauze dressings lead to fewer infections?
- Does it allow flap procedures to be performed safely beyond 72 hours without increased infection rates? And
- Is it associated with fewer local or free flap procedures?
Echebiri et al (2015) evaluated the economic benefit of prophylactic NPWT on a closed laparotomy incision after cesarean delivery in comparison with standard post-operative dressing. These researchers designed a decision-analytic model from a third-party payer's perspective to determine the cost-benefit of prophylactic application of NPWT compared with standard post-operative dressing on a closed laparotomy incision after cesarean delivery. The primary outcome measure was the expected value of the cost per strategy. Baseline probabilities and cost assumptions were derived from published literature. These investigators conducted sensitivity analyses using both deterministic and probabilistic models. Cost estimates reflect 2014 U.S. dollars. Under the baseline parameters, standard post-operative dressing was the preferred strategy. Standard post-operative dressing and prophylactic NPWT cost $547 and $804 per strategy, respectively. Sensitivity analyses showed that prophylactic NPWT can be cost-beneficial if it is priced below $192; standard post-operative dressing is the preferred strategy among patients with surgical site infection rate of 14 % or less. If surgical site infection rates are greater than 14 %, prophylactic NPWT could be cost-beneficial depending on the degree of reduction in surgical site infections. At a surgical site infection rate of 30 %, the rate must be reduced by 15 % for NPWT to become the preferred strategy. Monte Carlo simulation of 1,000 patients in 1 million trials showed that standard post-operative dressing was the preferred cost-beneficial strategy with a frequency of 85 %. The authors concluded that their cost-benefit analysis provided economic evidence suggesting that NPWT should not be used on closed laparotomy incisions of patients with low risk of post-cesarean delivery surgical site infections. However, among patients with a high risk of surgical site infections, prophylactic NPWT is potentially cost-beneficial. Moreover, the authors stated that “additional studies, including RCTs, are needed to establish the effectiveness of NPWT on incisions intended to heal by primary intention”.
In an editorial that accompanied the afore-mentioned study, Rouse (2015) stated that “The question that needs to be answered first is whether negative pressure therapy has any efficacy; that is, does it reduce the rate of surgical site infection or improve other important health outcomes when applied as a primary wound dressing to women who have undergone cesarean delivery? Right now, there is no way to answer this question. We therefore should not assume, however conditionally, that among patients with a high risk of surgical site infections, prophylactic negative pressure wound therapy is potentially cost-effective …. Absent compelling trial results, it is baffling why any insurance company would or should pay for such therapy”.
Prophylactic Negative Pressure Wound Therapy After Ventral Hernia Repairs
Soares and colleagues (2015) stated that prophylactic incisional NPWT following ventral hernia repairs (VHRs) remains controversial. These researchers evaluated the impact of a modified NPWT system (hybrid-VAC or HVAC) on outcomes of open VHR. A 5-year retrospective analysis of all VHRs performed by a single surgeon at a single institution compared outcomes after HVAC versus standard wound dressings. Multi-variable logistic regression compared surgical site infections, surgical site occurrences, morbidity, and re-operation rates. These investigators evaluated 199 patients (115 HVAC versus 84 standard wound dressing patients). Mean follow-up was 9 months. The HVAC cohort had lower surgical site infections (9 % versus 32 %, p < 0.001) and surgical site occurrences (17 % versus 42 %, p = 0.001) rates. Rates of major morbidity (19 % versus 31 %, p = 0.04) and 90-day reoperation (5 % versus 14 %, p = 0.02) were lower in the HVAC cohort. The authors concluded that the HVAC system is associated with optimized outcomes following open VHR. They stated that prospective studies should validate these findings and define the economic implications of this intervention.
Rodriguez-Unda and associates (2015) noted that despite improved operative techniques, open VHR surgery in high-risk, potentially contaminated patients remains challenging. As previously reported by this group of researchers, the use of a modified NPWT system (hybrid-VAC or HVAC) in patients with grade 2 hernias is associated with lower surgical site occurrence (SSO) and surgical site infection (SSI) rates. Accordingly, these investigators examined if the HVAC would similarly improve surgical site outcomes following VHR in patients with grade 3 hernias. A 4-year retrospective review (2011 to 2014) was conducted of all consecutive, modified ventral hernia working group (VHWG) grade 3 hernia repairs with HVAC closure performed by a single surgeon (FEE) at a single institution. Operative data and 90-day outcomes were evaluated. Overall outcomes (e.g., recurrence, re-operation, mortality) were reviewed for the study group. A total of 117 patients with an average age of 56.7 ± 11.9 years were classified as grade 3 hernias and underwent open VHR with subsequent HVAC closure; 50 patients were male (42.7 %), the mean BMI was 35.2 (± 9.5), and 60.7 % had a history of prior hernia repair. The average fascial defect size was 201.5 (± 167.3) cm(2) and the mean length of stay was 14.2 (± 9.3) days; 90-day outcomes showed an SSO rate of 20.7 % and an SSI rate of 5.2 %. The overall hernia recurrence rate was 4.2 % (n = 6) with a mean follow-up of 11 ± 7.3 months. The authors concluded that modified VHWG grade 3 ventral hernias are associated with significant morbidity. In this series utilizing the HVAC system after VHR, the observed rate of SSO and SSI compared favorably to reported series. They stated that further prospective cost-effective studies are needed to validate these findings.
In a systematic review and meta-analysis, Guo and colleagues (2022) examined the effectiveness of pNPWT in preventing SSI, hernia recurrence and other wound complications following closed laparotomy incisions following VHR. These researchers carried out a comprehensive literature search of PubMed, the Cochrane Central Register of Controlled Trials, Embase and ClinicalTrials.gov databases from inception until June 30, 2021, to identify all online English publications comparing the use of pNPWT with standard dressing for closed laparotomy incision following VHR. One RCT and 11 retrospective cohort studies involving 1,355 patients satisfied the basic inclusion criteria. The use of pNPWT reduced SSI (OR = 0.39 [95 % CI: 0.24 to 0.62] p < 0.0001) and SSO (OR = 0.51 [95 % CI: 0.27 to 0.98] p = 0.04). No statistically significant difference was detected in the incidence of hernia recurrence (OR = 0.61 [95 % CI: 0.30 to 1.26] p = 0.18), seroma (OR = 0.70 [95 % CI: 0.48 to 1.03] p = 0.07), hematoma (OR = 0.77 [95 % CI: 0.33 to 1.81] p = 0.55) and wound dehiscence (OR = 0.68 [95 % CI: 0.43 to 1.08] p = 0.10). The authors concluded that the use of pNPWT for closed laparotomy incisions following VHR can significantly reduce the rate of post-operative SSI (especially for superficial SIS) and SSOs. The NNT for preventing 1 occurrence of SSI is 9 patients. Moreover, these researchers stated that further research and more high-quality studies are needed to examine the effectiveness and aid in clarifying the role of pNPWT for closed laparotomy incisions following VHR, preferentially in high-risk populations of developing SSI.
Intermittent-Instillation NPWT
Dale and Saeed (2015) noted that the use of NPWT with instillation (NPWTi) in complex or difficult-to-treat acute and chronic wounds has expanded rapidly since the introduction of commercially available NPWTi systems. These researchers summarized the evidence related to NPWTi and particularly focus on the application of this technology in diabetic foot ulcers, diabetic foot infections and post-operative diabetic wounds. The benefits of NPWT are well-documented in the treatment of complex acute and chronic wounds, including non-infected post-operative diabetic wounds and diabetic foot ulcers. Combining intermittent wound irrigation with NPWT may offer additional benefits compared to NPWT alone, including further reduction of wound bed bio-burden, increased granulation tissue formation and provision of wound irrigation in a sealed environment, thus preventing potential cross-contamination events. Recently, available evidence suggested that adjunctive NPWTi may be superior to standard NPWT in the management of diabetic infections following surgical debridement and may promote granulation tissue formation in slow-to-heal wounds. The authors concluded that available evidence relating to the utilization of NPWTi in diabetic foot infections is promising but limited in quality, being derived mostly from case series or small retrospective or prospective studies. They stated that in order to confirm or refute the potential benefits of NPWTi in this patient cohort, well-designed RCTs are needed that compare NPWTi to NPWT or standard wound care methodologies.
Kim et al (2015) noted that NPWTi is a novel treatment option that provides the combination of negative pressure with intermittent instillation of a solution. Standard NPWT is an established adjunctive treatment option that offers the ability to promote granulation tissue in wounds. However, there is limited evidence for its utility in the environment of active or senescent infection. Wounds that are acutely infected or that contain deleterious biofilm are a challenging problem, which require an intensive multi-modal approach including antibiosis, surgical intervention, and local wound care. Adjunctive application of NPWTi can potentially expedite clearance of infection and wound closure. Although this technology has been commercially available for over 10 years, its adoption has been limited. Recently, there has been a resurgence of interest in this therapy with emerging evidence from animal models as well as human clinical studies. The authors concluded that there are remaining questions regarding NPWTi including the selection of the optimal instillation solution and device settings.
Gupta et al (2016) stated that NPWT is a well-established advanced therapy that has been successful in adjunctive management of acute and chronic wounds. In recent years, the introduction of topical wound solution delivery in combination with NPWT has provided further benefits to wound healing. A commercially available system now offers automated, volumetric control of instilled topical wound solutions with a dwell time in combination with NPWT (NPWTi-d; V.A.C. VeraFlo™ Therapy, KCI, an Acelity company, San Antonio, TX). This NPWTi-d system differs from other instillation systems in that a timed, pre-determined volume of topical wound solution is intermittently delivered (versus continuously fed) and allowed to dwell in the wound bed (without NPWT), for a user-selected period of time before NPWT is resumed. This added accuracy and process simplification of solution delivery in tandem with NPWT have prompted use of NPWTi-d as first-line therapy in a wider subset of complex wounds. However, considerably more research is needed to validate effectiveness of NPWTi-d in various wound types. These investigators provided a relevant overview of wound healing; described current literature supporting the adjunctive use of NPWTi-d; proposed a clinical approach for appropriate application of NPWTi-d; and concluded with case studies demonstrating successful use of NPWTi-d. The authors concluded that either a large case series examining effects of NPWTi-d on different wound types or possibly a large prospective registry evaluating NPWTi-d with real-world topical wound solutions versus immediate debridement and closure would be valuable to the medical community in evaluating the effectiveness of this promising therapy.
Burn Wounds
Fischer and associates (2016) stated that the use of NPWT is associated with improved outcomes in smaller burns. These investigators reported their experience using extra-large (XL) NPWT dressings to treat greater than or equal to 15 % total body surface area (TBSA) burned and described their technique and early outcomes. They also provided NPWT exudate volume for predictive fluid resuscitation in these critically ill patients. These researchers retrospectively reviewed patients treated with XL-NPWT from 2012 to 2014. Following excision/grafting, graft and donor sites were sealed with a layered NPWT dressing. They documented wound size, dressing size, NPWT outputs, graft take, wound infections, and length of stay (LOS). Mean NPWT exudate volume per %TBSA per day was calculated. A total of 12 burn patients (mean TBSA burned 30 %, range of 15 to 60 %) were treated with XL-NPWT (dressing TBSA burned and skin graft donor sites range 17 to 44 %). Average graft take was 97 %; no wound infections occurred; 2 patients had burns greater than or equal to 50 % TBSA and their LOS was reduced compared to ABA averages. XL-NPWT outputs peaked at day 1 after grafting followed by a steady decline until dressings were removed. Average XL-NPWT dressing output during the first 5 days was 101 ± 66 ml/%BSA covered per day; 2 patients developed acute kidney injury. The authors concluded that the use of XL-NPWT to treat extensive burns is feasible with attention to application technique; NPWT dressings appeared to improve graft take, and to decrease risk of infection, LOS, and pain and anxiety associated with wound care. Measured fluid losses can improve patient care in future applications of NPWT to large burn wounds.
Kantak and colleagues (2016) stated that negative pressure has been employed in various aspects of burn care and these investigators evaluated the evidence for each of those uses. The PubMed and Cochrane CENTRAL databases were queried for articles in the following areas: negative pressure as a dressing for acute burns, intermediate treatment prior to skin grafting, bolster for skin autografts, dressing for integration of dermal substitutes, dressing for skin graft donor sites, and integrated dressing in large burns. A total of 15 studies met inclusion criteria; 1 study showed NPWT improved perfusion in acute partial-thickness burns, 8 out of 9 studies showed benefits when used as a skin graft bolster dressing, 1 out of 2 studies showed improved rate of re-vascularization when used over dermal substitutes, and 1 study showed increased rate of re-epithelialization when used over skin graft donor sites. The authors concluded that negative pressure can improve autograft take when used as a bolster dressing. There is limited data to suggest that it may also improve the rate of re-vascularization of dermal substitutes and promote re-epithelialization of skin graft donor sites. Other uses suggested by studies that did not meet inclusion criteria include improving vascularity in acute partial-thickness burns and as an integrated dressing for the management of large burns. They stated that further studies are needed for most clinical applications to establish negative pressure as an effective adjunct in burn wound care.
Following Cardiac Surgery
Santarpino and colleagues (2015) stated that bilateral internal thoracic artery (BITA) grafting may be associated with a higher risk of post-operative deep sternal wound infection than monolateral internal thoracic artery grafting due to a limited blood supply to the thoracic chest wall. Because preliminary studies suggested NPWT may reduce the risk of infection, a retrospective chart review of 129 patients who underwent BITA between February 2003 and October 2014 was conducted. Of those, 21 patients received NPWT for 5 days immediately following surgery and the incisions of 108 patients were covered with a conventional gauze dressing. Patient demographic and history variables as well as surgical procedure and outcome variables were abstracted. Outcome variables assessed included infection, need for transfusion, and length of hospital stay. The NPWT group was significantly younger (average age of 55.9 ± 7.6 versus 60 ± 10.5 years, p = 0.049), had fewer urgent/emergent surgeries (4 [19 %] versus 36 [33.3 %], p = 0.247), and had significantly lower surgical risk scores (2.0 ± 2.3 versus 3.8 ± 2.8, p = 0.010). The rate of deep sternal wound infections was lower in the NPWT than in the control group, but the difference was not statistically significant (0 % versus 5.6 %, p = 0.336). Sternal instability was noted in 4 control patients, requiring wound re-exploration versus 0 in the NPWT group (3.7 % versus 0 %, p = 0.487); 1 patient in the NPWT group had post-operative bleeding that required removal of the device. The rates of re-thoracotomy due to bleeding were 9.3 % in the control compared to 4.8 % in the NPWT group (p = 0.435), which translated into a greater need for blood transfusions (1.77 ± 3.4 units versus 0.3 3± 0.7 units, p = 0.056) and larger chest drainage volume (997.8 ± 710 ml versus 591.2 ± 346 ml, p = 0.012) in the control group. Hospital stay was longer in the control group, but the difference was not statistically significant (12 ± 8.8 days versus 9.4 ± 4.2 days, p = 0.184). The authors concluded that these preliminary results were encouraging, and prospective RCTs to compare the efficacy, effectiveness, and cost-effectiveness of NPWT to other wound management modalities following cardiac surgery are needed.
Following Knee Arthroplasty
In a RCT, Manoharan and colleagues (2016) evaluated the effect of NPWT on quality of life (QoL), wound complications, and cost after primary knee arthroplasty. This was a prospective analysis of 33 patients undergoing primary knee arthroplasty performed by 3 surgeons in 1 institution. The first 12 patients (3 bilateral and 9 unilateral) had conventional dry dressings (CDD) applied and cost of dressings was assessed. The other 21 patients all underwent bilateral knee arthroplasty and had either side randomized to receiving NPWT or CDD. Cost of dressings, wound complications, and QoL were compared. One patient had a reaction to the NPWT requiring re-admission. Another had persistent wound drainage that required NPWT application. There were no wound issues in the remaining 31 patients. The average cost in the first 12 patients was Australian dollar $48.70 with an average of 1.5 changes on ward. In the 21 patients receiving both dressings, the average cost for CDD was less (Australian dollar $43.51 versus $396.02, p ≤ 0.011, effect size [ES] = 1.06). When comparing QoL factors, wound leakage (0.14 versus 0.39, p = 0.019, ES = 1.02), and wound protection (0.16 versus 0.33, p = 0.001, ES = 0.021) were better in the NPWT group. There was no other significant difference in QoL factors. The average number of changes on the ward was less for the NPWT group (1.19 versus 1.38, p = 0.317, ES = 1.02). The authors found no benefit in wound healing or cost with NPWT following knee arthroplasty. There was some benefit in NPWT QoL factors less wound leakage and better protection.
Kidney Transplant Recipients
Shrestha and colleagues (2016) reviewed NPWT as an addition to the conventional methods of wound management in kidney transplant recipients. A systematic review, performed by searching the PubMed, Embase and Cochrane Library databases, showed 11 case reports comprising a total of 22 kidney transplantation (KT) patients (range of 1 to 9), who were treated with NPWT. Application of NPWT was associated with successful healing of wounds, leg ulcer, lymphocele and urine leak from ileal conduit. No complications related to NPWT were reported. However, there was paucity of robust data on the effectiveness of NPWT in KT recipients; therefore, prospective studies evaluating the safety and effectiveness of NPWT and randomized trials comparing the effectiveness of NPWT with alternative modalities of wound management in KT recipients is recommended. The authors concluded that negative pressure incision management system, NPWT with instillation and endoscopic vacuum-assisted closure system are in investigational stage.
Reduction of Surgical Site Infections Following Resection of Intra-Abdominal Malignancies
Shen and colleagues (2017) noted that surgical site infections (SSI) remain a major source of morbidity and cost following resection of intra-abdominal malignancies; and NPWT has been reported to significantly decrease SSI when applied to the closed laparotomy incision. These investigators reported results of a randomized, phase II clinical trial, clinical trial examining the effect of NPWT on SSI rates in surgical oncology patients with increased risk for infectious complications. From 2012 to 2016, a total of 265 patients underwent open resection of intra-abdominal neoplasms were stratified into 3 groups:- gastro-intestinal (n = 57),
- pancreas (n = 73), and
- peritoneal surface malignancy (n = 135).
They were randomized to NPWT or standard surgical dressing (SSD) applied to the incision from post-operative day 1 through 4. Primary outcomes of combined incisional (superficial and deep) SSI rates were assessed up to 30 days after surgery. There were no significant differences in superficial SSI, 12.8 % versus 12.9 % (p => 0.99) or deep SSI, 3.0 % versus 3.0 % (p => 0.99) rates between the SSD and NPWT groups, respectively. When stratified by type of surgery there were still no differences in combined incisional SSI rates for gastro-intestinal, 25 % versus 24 % (p => 0.99), pancreas, 22 % versus 22 % (p => 0.99), and peritoneal surface malignancy, 9 % versus 9 % (p => 0.99) patients. When performing univariate and multivariate logistic regression analysis of demographic and operative factors for the development of combined incisional SSI, the only independent predictors were pre-operative albumin (p = 0.0031) and type of operation (p = 0.018). The authors concluded that the use of NPWT did not significantly reduce incisional SSI rates in patients having open resection of gastro-intestinal, pancreatic, or peritoneal surface malignancies. They stated that based on these findings, NPWT cannot be currently recommended as a therapeutic intervention to decrease infectious complications in these patient populations.
Management of Closed Sternal Incision Following Thoracic Artery Grafting
Gatti and colleagues (2018) noted that single-use, closed incision management (CIM) systems offer a practical means of delivering NPWT to patients. This prospective study evaluates the Prevena Therapy system in a cohort of coronary patients at high-risk of deep sternal wound infection (DSWI). A total of 53 consecutive patients undergoing bilateral internal thoracic artery (BITA) grafting were pre-operatively elected for CIM with the Prevena Therapy system, which was applied immediately after surgery. The actual rate of DSWI in these patients was compared with the expected risk of DSWI according to 2 scoring systems specifically created to predict either DSWI after BITA grafting (Gatti score) or major infections after cardiac surgery (Fowler score). The actual rate of DSWI was lower than the expected risk of DSWI by the Gatti score (3.8 % versus 5.8 %, p = 0.047) but higher than by the Fowler score (2.3 %, p = 0.069). However, while the Gatti score showed very good calibration (χ2 = 4.8, p = 0.69) and discriminatory power (area under the receiver-operating characteristic curve 0.838), the Fowler score showed discrete calibration (χ2 = 10.5, p = 0.23) and low discriminatory power (area under the receiver-operating characteristic curve 0.608). The authors concluded that single-use CIM systems appeared to be useful to reduce the risk of DSWI after BITA grafting. Moreover, they stated that more studies are needed to make stronger this finding.
Management of Closed Sternal Incision Following Mammoplasty
In a prospective, randomized study, Tanaydin and associates (2018) compared disposable NPWT with standard care in bilateral breast reduction mammoplasty evaluating surgical site complications and scar quality. This trial included 32 patients who underwent bilateral breast reduction mammoplasty. Patients served as their own control and received NPWT to one breast and fixation strips to the other breast. The primary outcome was the number of wound healing complications within 21 days when comparing NPWT treatment with fixation strips. The secondary outcome was aesthetic appearance and quality of scarring using questionnaires [VAS and Patient and Observer Scar Assessment Scale (POSAS)] scored at day 42-, 90-, 180- and 365-day follow-up using additional scar measurement modalities, such as viscoelasticity. For the 32 included patients, the number of wound complications was significantly lower (p < 0.004) for the NPWT treated sites compared to fixation strips. POSAS and VAS scores at 42 and 90 days revealed a significantly better quality of scarring in the NPWT treatment breasts than in fixation strips. At 180-day follow-up, there was a significant improvement in VAS scores, as well as a comparable improvement in POSAS scores. No consistent significant improvement in scar quality was demonstrated with the assays that were used. The authors concluded that the findings of this study showed less wound healing complications and a statistically significant improvement in the aesthetic appearance and quality of scarring for the NPWT-treated sites versus those breasts that received standard care with fixation strips. The results indicated NPWT to be an attractive option for closed surgical incision treatment. They noted that although the clinical significance of reduced scarring may be not of utmost importance for the surgeon, it is imperative for the patient’s emotional well-being and quality of life (QOL).
The authors stated that this study had several drawbacks. Given the nature of the treatments, it was not possible to conduct a double-blind trial. Ideally, a control group with the same non-activated device would have been better, but this would still have been noted by the patient and physician. Therefore, investigator and patient bias scoring POSAS and VAS could not be ruled out. The authors’ intention was to at least blind the investigator, which was unsuccessful due to practical reasons, e.g., the assessor was not available. Instead, the investigator did not know the randomization schedule and the patients were asked not to reveal it. No consistent significant improvement in scar viscoelasticity was demonstrated. This could be due to measurements being performed with different probes and other external factors influencing results. Even after standardizing measurement locations, it proved difficult to exactly measure the same section of scar/skin during follow-up. Moreover, some patients had such a fine scar that the probes were overlapping onto normal skin. Although these researchers tried to keep a steady room temperature and air humidity, thereby minimizing environmental factors, this was practically impossible at the out-patient clinic. During the follow-up period, seasons changed making the comparison of trans-epidermal water loss in serial follow-ups difficult. Some patients were stressed because they were late or had put on body lotion when they were not supposed to.
This was a small study (n = 32); its findings need to be validated by well-designed studies.
Prophylaxis after Lower Extremity Fracture Surgery
In a prospective, case-series, pilot study, Dingemans and co-workers (2018) examined the feasibility of a new portable single-use NPWT device in patients undergoing major foot ankle surgery. Patients undergoing major foot ankle fracture surgery at a single level 1 trauma center were eligible for this trial. Patient characteristics were collected, as were fracture and surgical characteristics. Primary outcome was surgical site infection (SSI) within 30 days as classified by the criteria from the Centers for Disease Control and Prevention (CDC). Patients in the prospective cohort were case-matched with a historical cohort from the same institution. A total of 60 patients were included. In 7 patients, the NPWT failed and treatment was terminated. Mean age was 44 years and 85 % was American Society of Anesthesiologists (ASA) 1; 43 % of the patients were actively smoking. Indications for surgery were mid-foot, calcaneal, talar, and ankle fractures. In 53 patients, 4 (7.5 %) surgical site infections occurred, 2 superficial (3.3 %) and 2 (3.3 %) deep infections. For 47 patients, a match was available. The incidence of surgical site infection did not statistically significantly differ between the prospective cohort and retrospective matched cohort (4.3 % versus 14.9 %, p = 0.29, respectively). This was also the case when looking at superficial and deep surgical site infections separately (0 % versus 8.5 %, p = 0.08, and 4.3 % versus 6.4 %, respectively). The authors concluded that they had observed surgical site infections in 7.5 % of the patients with the use of prophylactic negative pressure wound therapy. The incidence of surgical site infections was not statistically significantly lower compared to a matched historical cohort. Moreover, they stated that the results were promising and a larger study with adequate power could provide more insight in the possible beneficial effect of prophylactic negative pressure wound therapy; the results of this study can be used as a benchmark for the development of a future prospective randomized study on NPWT.
The authors stated that this study had several drawbacks. First, these investigators were unable to find an appropriate match for 2 patients with a superficial SSI. The first patient (51-year old, actively smoking woman who had already experienced a deep SSI following ORIF for a calcaneal fracture) underwent surgery for a secondary arthrodesis through the ELA. From earlier research, the authors knew that patients who have experienced a SSI prior to a secondary procedure are at risk for developing a wound complication. For this reason, patients were matched on this criterion when undergoing secondary procedures. However, as secondary arthrodeses were not performed regularly, we were not able to identify a match for this patient and therefore had to eliminate her from the analysis. For the second patient (75-year old woman, non-smoking) with an ankle fracture, no match was available either. These types of fractures were generally not treated in the authors’ tertiary referral university hospital. As a result, the number of patients available for matching was low. The fact that these 2 patients were not included in the matching analysis should be noticed, and the results should be interpreted with care. Second, although matching for several factors, which were recognized for being influential on the development of wound complications, it could not be ruled out that residual confounding exist through factors not matched for. Third, it must be noted that the time span of the historical cohort from which the patients were drawn was 16 years. During these 16 years, major changes in treatment insights may have developed. As a result of this, the SSI rate in the control group may be higher than what could be expected using contemporary techniques; this should be kept in mind when interpreting the results from the matched cohorts. Lastly, the authors did not compare wound dehiscence among the 2 groups. They observed 3 cases of wound dehiscence in this case-series study. However, as these researchers collected data on the matching database retrospectively, they felt that they could not reliably identify all cases of wound dehiscence in this group. For this reason, they chose not to compare the incidence of wound dehiscence between the 2 groups. It is well recognized that the incidence of complications is lower in retrospective studies due to insufficient documentation of complications. Thus, possible wound complications in patients in the matching database may not have been identified, and the incidence in the control may be higher.
Management of Fasciotomy Wounds in Persons with Compartment Syndrome
Cone and Inaba (2017) noted that lower extremity compartment syndrome is a devastating complication if not rapidly diagnosed and properly managed. The classic symptoms of compartment syndrome can be deceiving as they occur late. Any concern for compartment syndrome based on mechanism, or the presence of pain in the affected extremity, should prompt a compartment pressure check. Both absolute compartment pressures above 30 mm Hg and a pressure differential of less than 30 mm Hg are used to make the diagnosis. The treatment goal is first to save the patient’s life and second to salvage the affected limb. Fasciotomy is the only accepted treatment of compartment syndrome and should be performed quickly after the diagnosis is made. Outcomes after fasciotomy are best when there is no delay in treatment. These investigators stated that there is evidence that the use of a vacuum-assisted closure dressing is associated with significantly higher rates of primary closure than traditional dressings.
Jauregui and colleagues (2017) stated that currently there is no consensus regarding which technique should be used when closing fasciotomy incisions. Wound closure technique is based on the surgeon’s preference and the requirements of each clinical scenario. These investigators conducted a systematic literature review to evaluate the current evidence regarding fasciotomy closure techniques. The objectives of this study were to determine the current techniques available for fasciotomy wound closure; assess the overall success of these techniques in achieving wound closure in the extremities; and examine the effectiveness of these techniques in minimizing the time needed for fasciotomy wound closure and complication rates. These researchers found that after evaluating 23 studies, they determined that the highest success rate was observed for dynamic dermato-traction (93 %) and gradual suture approximation (92 %), followed by VAC (78 %). However, VAC had the lowest complication rate (2 %), followed by gradual suture approximation (15 %), and then dynamic dermato-traction (18 %). The authors concluded that that currently there are many surgeons who prefer VAC systems. In this meta-analysis, VAC systems had the lowest success rate but also had the lowest complication rate. In this study, defining success as closure without STSG may not be an accurate representation of what a surgeon deems successful, following a severe extremity injury requiring fasciotomies. Furthermore, in a patient who is already at high risk for complications due to the severe nature of the injury that lead to ACS, VAC systems may be the best choice.
The American Academy of Orthopedic Surgeons (AAOS, 2018) had a qualified recommendation for NPWT for compartment syndrome.
Furthermore, an UpToDate review on “Patient management following extremity fasciotomy” (Modrall, 2019) states that “We use saline gauze dressings in the immediate postoperative period to allow frequent wound evaluation and interval debridement of necrotic tissue, as needed. Once the fasciotomy wounds are stable, we use active tension (e.g., shoelace technique) with negative pressure wound therapy (NPWT) to facilitate fasciotomy closure”.
Prophylactic Negative-Pressure Wound Therapy After Cesarean Delivery
In a systematic review and meta-analysis, Yu and colleagues (2018) examined the effect of prophylactic NPWT on surgical site infections and other wound complications in women after cesarean delivery. These investigators searched Ovid Medline, Embase, SCOPUS, Cochrane Database of Systematic Reviews, and ClinicalTrials.gov. They included RCTs and observational studies comparing prophylactic NPWT with standard wound dressing for cesarean delivery. The primary outcome was surgical site infection after cesarean delivery; secondary outcomes were composite wound complications, wound dehiscence, wound seroma, endometritis, and hospital re-admission. Heterogeneity was assessed using Higgin's I2; RRs with 95 % CIs were calculated using random-effects models. A total of 6 RCTs and 3 cohort studies in high-risk mostly obese women met inclusion criteria and were included in the meta-analysis; 6 were full-text articles, 2 published abstracts, and 1 report of trial results in ClinicalTrials.gov. Studies were also heterogeneous in the patients included and type of NPWT device. The risk of surgical site infection was significantly lower with the use of prophylactic NPWT compared with standard wound dressing (7 studies: pooled RR, 0.45; 95 % CI: 0.31 to 0.66; adjusted RR, -6.0 %, 95 % CI: -10.0 % to -3.0 %; number needed to treat, 17, 95 % CI: 10 to 34). There was no evidence of significant statistical heterogeneity (I2 = 9.9 %) or publication bias (Egger p = 0.532). Of the secondary outcomes, only composite wound complications were significantly reduced in patients receiving prophylactic NPWT compared with standard dressing (9 studies: pooled RR, 0.68, 95 % CI: 0.49 to 0.94). The authors concluded that studies on the effectiveness of prophylactic NPWT at cesarean delivery were heterogeneous; but suggested a reduction in surgical site infection and overall wound complications. Moreover, these researchers stated that larger definitive trials are needed to clarify the clinical utility of prophylactic NPWT after cesarean delivery.
In a cost-effectiveness analysis conducted alongside a clinical trial, Hyldig and associates (2019) evaluated the cost-effectiveness of incisional NPWT (iNPWT) in preventing SSI in obese women after caesarean section. Subjects were women with a pre-gestational body mass index (BMI) of greater than or equal to 30 kg/m2. These investigators used data from a RCT of 876 obese women who underwent elective or emergency caesarean section and were subsequently treated with iNPWT (n = 432) or a standard dressing (n = 444). Costs were estimated using data from 4 Danish National databases and analyzed from a healthcare perspective with a time horizon of 3 months after birth. Main outcome measures were cost-effectiveness based on incremental cost per surgical site infection avoided and per quality-adjusted life-year (QALY) gained. The total healthcare costs per woman were €5,793.60 for iNPWT and €5,840.89 for standard dressings. Incisional NPWT was the dominant strategy because it was both less expensive and more effective; however, no statistically significant difference was found for costs or QALYs. At a willingness-to-pay threshold of €30,000, the probability of the intervention being cost-effective was 92.8 %. A subgroup analysis stratifying by BMI showed that the cost saving of the intervention was mainly driven by the benefit to women with a pre-pregnancy BMI greater than or equal to 35 kg/m2. The authors concluded that incisional NPWT appeared to be cost saving compared with standard dressings; however this finding was not statistically significant. The cost savings were primarily found in women with a pre-pregnancy BMI greater than or equal to 35 kg/m2.
Tuuli (2019) stated that prophylactic NPWT has emerged as a promising intervention in patients at high risk for SSI. One such group is obese gravidae, a growing population worldwide who are at high risk for both cesarean delivery and SSI. Although the precise mechanism by which NPWT aids incisional wound healing is unclear, experimental evidence suggested that it reduces bacterial contamination, edema, and exudate, increases microvascular blood flow, promotes formation of granulation tissue and reduces lateral tensile and shear stress. The author noted that data on NPWT after cesarean have been limited to retrospective cohort and small pilot RCTs. Whereas some studies demonstrated benefit in reducing SSI and other wound complications, they were limited by small sample sizes, selection bias and confounding factors.
Vascular Surgery (Including Closed Groin Incisions in Arterial Surgery)
Svensson-Bjork and colleagues (2019) noted that SSI following groin incisions in arterial surgery is common and may lead to amputation or death. Incisional NPWT dressings have been suggested to reduce SSIs. In a systematic review with meta-analysis, these researchers examined the effects of incisional NPWT on the incidence of SSI in closed groin incisions following arterial surgery. A study protocol for this systematic review of RCTs was published in Prospero (CRD42018090298) a priori, with pre-defined search, inclusion and exclusion criteria. The records generated by the systematic research were screened for relevance by title and abstract and in full text by 2 of the authors independently. The selected articles were rated for bias according to the Cochrane risk-of-bias tool. Among 1,567 records generated by the search, 7 RCTs were identified, including 1,049 incisions. Meta-analysis showed a reduction in SSI with incisional NPWT (odds ratio (OR) 0.35, 95 % CI: 0.24 to 0.50; p < 0.001). The heterogeneity between the included studies was low (I2 = 0 %). The quality of evidence was graded as moderate; 2 studies had multiple domains in the Cochrane risk-of-bias tool rated as high risk of bias. A subgroup meta-analysis of 3 studies of lower limb re-vascularization procedures only (363 incisions) demonstrated a similar reduction in SSI (OR 0.37, 95 % CI: 0.22 to 0.63; p < 0.001; I2 = 0 %). The authors concluded that incisional NPWT following groin incisions for arterial surgery reduced the incidence of SSI compared with standard wound dressings. Moreover, they stated that the risk of bias highlighted the need for a high-quality RCT with cost-effectiveness analysis.
Wee and co-workers (2019) stated that closed incision NPWT (CiNPWT) may be a valuable therapeutic option for surgical site infections. In a systematic review and meta-analysis, these researchers compared CiNPWT against conventional wound care after vascular procedures. This study conformed to the PRISMA guidelines. An electronic search was performed on Medline/PubMed, Embase, and the Cochrane Library. The date of last search was July 11 2018; RRS and MDs for primary and secondary outcomes were calculated. A random effects model was used for substantial heterogeneity (I2 > 30 %). The Cochrane Risk of Bias tool was employed to rate the methodological quality of the included studies, while the GRADE approach was use to grade the level of evidence for the observed effects. Of 47 studies, 5 RCTs were included, comprising 662 patients, of which 47.9 % underwent CiNPWT and 52.1 % received conventional care. The overall risk of infection (RR = 0.31, 95 % CI: 0.21 to 0.47) (high quality), Szilagyi Grades I (RR = 0.35, 95 % CI 0.20 to 0.60) (high quality), and III (RR = 0.17, 95 % CI: 0.04 to 0.68) (high quality) infections, need for antibiotics (RR = 0.36, 95 % CI: 0.20 to 0.64) (high quality), and surgical re-intervention (RR = 0.27, 95 % CI: 0.27 to 0.98) (high quality) were lower in the CiNPWT group. However, there were no significant differences in the risk of Grade II (RR = 0.59, 95 % CI: 0.10 to 3.66) (moderate quality), as well as length of hospital stay (MD = -0.59, 95 % CI: -2.48 to 1.31) (moderate quality), and 30-day mortality (RR = 3.95, 95 % CI: 0.17 to 94.76) (high quality). The authors concluded that while there is evidence demonstrating that CiNPWT reduced the risk of Grades I and III infections and re-interventions, there was a noticeable lack of difference in other important post-operative outcomes. These researchers stated that further well-designed RCTs are needed to corroborate these findings.
Bertges and colleagues (2021) noted that wound complications following open infra-inguinal re-vascularization are a frequent cause of patient morbidity, resulting in increased healthcare costs. In a prospective, randomized, multi-center study, these researchers examined the effects of ciNPWT on groin wound complications following infra-inguinal bypass and femoral endarterectomy. A total of 242 patients who had undergone infra-inguinal bypass (n = 124) or femoral endarterectomy (n = 118) at 5 academic medical centers in New England from April 2015 to August 2019 were randomized to ciNPWT (PREVENA; 3M KCI, St Paul, MN; n = 118) or standard gauze (n = 124). The primary outcome measure was a composite endpoint of groin wound complications, including SSIs, major non-infectious wound complications, or graft infections within 30 days after surgery. The secondary outcome measures included 30-day SSIs, 30-day non-infectious wound complications, re-admission for wound complications, significant AEs, and health-related QoL (HR-QoL) using the EuroQoL 5D-3L survey. The ciNPWT and control groups had similar demographics (age of 67 versus 67 years, p = 0.98; male gender, 71 % versus 70 %, p = 0.86; white race, 93 % versus 93 %, p = 0.97), co-morbidities (previous or current smoking, 93 % versus 94 %, p = 0.46; diabetes, 41 % versus 48 %, p = 0.20; renal insufficiency, 4 % versus 7 %, p = 0.31), and operative characteristics, including procedure type, autogenous conduit, and operative time. No differences were found in the primary composite outcome at 30 days between the 2 groups (ciNPWT versus control: 31 % versus 28 %; p = 0.55). The incidence of SSI at 30 days was similar between the 2 groups (ciNPWT versus control: 11 % versus 12 %; p = 0.58). Infectious (13.9 % versus 12.6 %; p = 0.77) and non-infectious (20.9 % versus 17.6 %; p = 0.53) wound complications at 30 days were also similar for the ciNPWT and control groups. Wound complications requiring re-admission also similar between the 2 groups (ciNPWT versus control: 9 % versus 7 %; p = 0.54). The significant AE rates were not different between the 2 groups (ciNPWT versus control: 13 % versus 16 %; p = 0.53). The mean length of the initial hospitalization was the same for the ciNPWT and control groups (5.2 versus 5.7 days; p = 0.63). The overall HR-QoL was similar at baseline and at 14 and 30 days post-operatively for the 2 groups. Although not powered for stratification, these investigators found no differences among the subgroups in gender, obesity, diabetes, smoking, claudication, chronic limb threatening ischemia, bypass, or endarterectomy. On multi-variable analysis, no differences were found in wound complications at 30 days for the ciNPWT versus gauze groups (OR, 1.4; 95 % CI: 0.8 to 2.6; p = 0.234).
The authors concluded that in contrast to other randomized studies, this randomized, multi-center trial of infra-inguinal re-vascularization found no differences in the 30-day groin wound complications for patients treated with ciNPWT versus standard gauze dressings. However, the SSI rate was lower in the control group than reported in other studies, suggesting other practice patterns and processes of care might have reduced the rate of groin infections. These researchers stated that further study might identify the subsets of high-risk patients that could benefit from ciNPWT.
Open Fracture / Traumatic Wounds
In a Cochrane review, Iheozor-Ejiofor and colleagues (2018) examined the effects of NPWT for treating open traumatic wounds in people managed in any care setting. In June 2018, these investigators searched the Cochrane Wounds Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Ovid Medline (including in-process and other non-indexed citations), Ovid Embase and EBSCO CINAHL Plus. They also searched clinical trials registries for ongoing and unpublished studies, and scanned reference lists of relevant included studies as well as reviews, meta-analyses and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting. Published and unpublished RCTs that used NPWT for open traumatic wounds involving either open fractures or soft tissue wounds were selected for analysis; primary outcomes were wound healing, wound infection and adverse events (AEs). Two review authors independently selected eligible studies, extracted data, carried out a “risk of bias” assessment and rated the certainty of the evidence. Data were presented and analyzed separately for open fracture wounds and other open traumatic wounds (not involving a broken bone). A total of 7 RCTs (1,377 participants recruited) met the inclusion criteria of this review. Study sample sizes ranged from 40 to 586 participants; 1 study had 3 arms, which were all included in the review; 6 studies compared NPWT at 125 mmHg with standard care: 1 of these studies did not report any relevant outcome data; 1 further study compared NPWT at 75 mmHg with standard care and NPWT 125 mmHg with NPWT 75 mmHg. Open fracture wounds (4 studies all comparing NPWT 125 mmHg with standard care); 1 study (460 participants) comparing NPWT 125 mmHg with standard care reported the proportions of wounds healed in each arm. At 6 weeks there was no clear difference between groups in the number of participants with a healed, open fracture wound: RR 1.01 (95 % CI: 0.81 to 1.27); moderate-certainty evidence, down-graded for imprecision. These researchers pooled data on wound infection from 4 studies (596 participants). Follow-up varied between studies but was approximately 30 days. On average, it was uncertain whether NPWT at 125 mmHg reduced the risk of wound infection compared with standard care (RR 0.48, 95 % CI: 0.20 to 1.13; I2 = 56 %); very low-certainty evidence down-graded for risk of bias, inconsistency and imprecision. Data from 1 study showed that there was probably no clear difference in health-related QOL between participants treated with NPWT 125 mmHg and those treated with standard wound care (EQ-5D utility scores mean difference (MD) -0.01, 95 % CI: -0.08 to 0.06; 364 participants, moderate-certainty evidence; physical component summary score of the short-form 12 instrument MD -0.50, 95 % CI: -4.08 to 3.08; 329 participants; low-certainty evidence down-graded for imprecision). Moderate-certainty evidence from 1 trial (460 participants) suggested that NPWT was unlikely to be a cost-effective treatment for open fractures in the United Kingdom. On average, NPWT was more costly and conferred few additional QALYs when compared with standard care. The incremental cost-effectiveness ratio was GBP 267,910 and NPWT was shown to be unlikely to be cost effective at a range of cost-per-QALYs thresholds. These investigators down-graded the certainty of the evidence for imprecision. Other open traumatic wounds (2 studies, 1 comparing NPWT 125 mmHg with standard care and a 3-arm study comparing NPWT 125 mmHg, NPWT 75 mmHg and standard care). Pooled data from 2 studies (509 participants) suggested no clear difference in risk of wound infection between open traumatic wounds treated with NPWT at 125 mmHg or standard care (RR 0.61, 95 % CI: 0.31 to 1.18); low-certainty evidence down-graded for risk of bias and imprecision; 1 trial with 463 participants compared NPWT at 75 mmHg with standard care and with NPWT at 125 mmHg. Data on wound infection were reported for each comparison. It was uncertain if there was a difference in risk of wound infection between NPWT 75 mmHg and standard care (RR 0.44, 95 % CI: 0.17 to 1.10; 463 participants) and uncertain if there was a difference in risk of wound infection between NPWT 75 mmHg and 125 mmHg (RR 1.04, 95 % CI: 0.31 to 3.51; 251 participants). These researchers down-graded the certainty of the evidence for risk of bias and imprecision. The authors concluded that there was moderate-certainty evidence for no clear difference between NPWT and standard care on the proportion of wounds healed at 6 weeks for open fracture wounds. There was moderate-certainty evidence that NPWT was not a cost-effective treatment for open fracture wounds. Moderate-certainty evidence means that the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. It was uncertain whether there was a difference in risk of wound infection, AEs, time-to-closure or coverage surgery, pain or health-related QOL between NPWT and standard care for any type of open traumatic wound.
In a Cochrane review, Webster and colleagues (2019) examined the effects of NPWT for preventing surgical site infection in wounds healing through primary closure. In this 2nd update, these researchers added 25 intervention trials, resulting in a total of 30 intervention trials (2,957 subjects), and 2 economic studies nested in trials. Surgeries included abdominal and colorectal (n = 5); caesarean section (n = 5); knee or hip arthroplasties (n = 5); groin surgery (n = 5); fractures (n = 5); laparotomy (n = 1); vascular surgery (n = 1); sternotomy (n = 1); breast reduction mammoplasty (n = 1); and mixed (n = 1). In 3 key domains, 4 studies were at low-risk of bias; 6 studies were at high-risk of bias; and 20 studies were at unclear risk of bias. These investigators deemed the evidence to be of low or very-low certainty for all outcomes, down-grading the level of the evidence on the basis of risk of bias and imprecision. The authors concluded that despite the addition of 25 trials, results were consistent with their earlier review, with the evidence judged to be of low or very-low certainty for all outcomes. Consequently, uncertainty remains regarding if NPWT compared with a standard dressing reduced or increased the incidence of important outcomes such as mortality, dehiscence, seroma, or if it increased costs. These researchers stated that given the cost and widespread use of NPWT for SSI prophylaxis, there is an urgent need for larger, well-designed and well-conducted trials to examine the effects of newer NPWT products designed for use on clean, closed surgical incisions. Such trials should initially focus on wounds that may be difficult to heal, such as sternal wounds or incisions on obese patients.
In a systematic review and meta-analysis, Grant-Freemantle and associates (2020) compared the efficacy of NPWT versus conventional dressings in the management of open fractures. These researchers carried out a systematic search of English articles in the PubMed/Medline, Embase and the Cochrane Library through April 2019 comparing NPWT versus conventional dressings in the management of open fractures. Inclusion criteria were articles in English language, comparing NPWT with conventional dressings in skeletally mature individuals who had sustained an open fracture at any anatomical site, reporting on rates of deep infection, flap frequency, flap failure, non-union, amputation, length of hospital or intensive care unit (ICU) stay. Two authors independently extracted data from selected studies and the data collected were compared to verify agreement. Pooled ORs were calculated for dichotomous outcomes while continuous data were analyzed using the standard weighted mean difference (WMD). A random or fixed effect model was used depending on the level of heterogeneity between studies. The authors concluded that NPWT resulted in decreased likelihood of deep infection and flap failure compared to conventional dressings in the management of open fractures not directly amenable to early closure.
In a systematic review and meta-analysis, Kim and Lee (2019) examined the effect of NPWT on decreasing the infection rate, amputation rate, nonunion rate, and flap-related complications in open tibia fractures. The Medline, Embase, and Cochrane Library databases were systematically searched. Complications were evaluated in terms of the rates of infection, amputation, nonunion, and flap-related complications. A total of 12 studies were included. In the meta-analysis, NPWT showed significantly lowered soft-tissue infection rate (OR] 0.48, 95 % CI: 0.34 to 0.68, p < 0.0001), nonunion rate (OR 0.61, 95 % CI: 0.39 to 0.95, p = 0.03), flap necrosis rate (OR 0.37, 95 % CI: 0.21 to 0.63, p = 0.0003), and flap revision rate (OR 0.44, 95 % CI: 0.22 to 0.89, p = 0.02) than conventional wound management. However, no significant difference was found in osteomyelitis rate (OR 0.54, 95 % CI: 0.09 to 3.28, p = 0.50) and amputation rate (OR 0.89, 95 % CI: 0.36 to 2.22, p = 0.80) between the 2 groups. The authors concluded that lower rates of soft-tissue infection, nonunion, flap necrosis, and flap revision were observed in the NPWT group than in the conventional dressing group. However, these researchers stated that additional high-quality studies are needed to validate the efficacy of NPWT in the treatment of severe open tibia fractures. They could not make a definitive conclusion regarding the comparative efficacy of the 2 methods in terms of complications because of insufficient data.
Post-Operative Transgender Surgeries to Improve Wound Healing
The World Professional Association for Transgender Health (WPATH)’s “Standards of Care for the Health of Transsexual, Transgender, and Gender Nonconforming People, 7th Version (Coleman et al, 2012) did not mention NPWT for post-operative care.
Furthermore, UpToDate reviews on “Negative pressure wound therapy” (Gestring, 2019), “Transgender surgery: Male to female” (Ferrando and Thomas, 2019), and “Transgender surgery: Female to male” (Ferrando et al, 2019) do not mention NPWT as a management option for post-operative transgender surgeries to improve wound healing.
Head and Neck Wounds with Fistulas
Lin and colleagues (2020) noted that fistula formation in head and neck wounds is considered one of the most challenging complications that a head and neck reconstructive surgeon may encounter. The current mainstay of treatment is aggressive surgical debridement followed by vascularized soft tissue coverage; NPWT has been successfully used for the closure of complicated wounds for decades. This study analyzed the outcomes and complications of NPWT in the management of head and neck wounds with fistulas. These researchers conducted a systematic search of studies published between January 1966 and September 2019 using the PubMed, Medline, Embase, and SCOPUS databases and using the following key words: "negative pressure wound therapy", "head and neck", and "fistula". They included human studies with abstract and full text available. Analyzed end-points were rate of fistula closure, follow-up duration, and complications if present. A total of 9 retrospective case series (Level IV evidence) that collectively included 122 head and neck wounds with oro-cutaneous fistulas, pharyngo-cutaneous fistulas, and salivary contamination were examined. The number of patients included in each study ranged from 5 to 64. The mode of NPWT varied among the included studies, with most adopting a continuous pressure of -125 mm Hg. Mean durations of NPWT ranged from 3.7 to 23 days, and the reported fistula closure rate ranged from 78 % to 100 %. To achieve complete wound healing, 6 studies used additional procedures after stopping NPWT, including conventional wound dressings and vascularized tissue transfer. Information regarding follow-up was provided in only 3 of the 9 studies, where patients were followed-up for 5, 10, and 18 months; no serious AEs were reported. The authors concluded that NPWT for head and neck wounds with fistulas may be considered a safe therapeutic method that yields beneficial outcomes with a low-risk of complications. The current data originated mainly from studies with low levels of evidence characterized by heterogeneity. Thus, these researchers stated that definitive recommendations based on these data could not be offered; additional high-quality trials are needed to corroborate the findings of this systematic review.
Pilonidal Disease
Bendewald et al (2007) stated that complex pilonidal disease, an uncommon manifestation of an anorectal condition, is characterized by chronic or recurrent abscesses with extensive, branching sinus tracts. Definitive treatment requires wide excision of all involved tissue followed by secondary intention healing or reconstructive surgery. All treatment options have unique advantages and disadvantages. Following recent reports that negative pressure wound therapy after surgery for complex pilonidal disease may be a useful alternative to moist saline dressing treatments, 5 patients (3 men and 2 women, median age of 21 years [range of 16 to 63 years]) with complex pilonidal disease (symptom duration range of 6 months to 30 years) were treated on an outpatient basis. Following wide excision under general anesthesia, a portable negative pressure wound therapy device was applied. Mean wound defect size after excision was 11 cm x 4 cm x 5 cm, or 205 cm(3) (range of 90 cm(3) to 410 cm(3)). Negative pressure wound therapy was used for an average of 6 weeks (range of 4 to 9 weeks) and mean time to complete epithelialization was 12 weeks (range of 9 to 22 weeks), including use of moist saline dressings post-negative pressure wound therapy. Treatment was discontinued in 1 patient due to skin irritation. No other complications were observed. The authors concluded that long-term follow-up is needed to assess the risk of recurrent pilonidal disease or wound failure following negative pressure wound therapy. They stated that additional studies of negative pressure wound therapy in the management of pilonidal disease are warranted.
Farrell and Murphy (2011) noted that pilonidal disease arises from hair follicles of the gluteal cleft and may result in a chronic exudative disorder. The management of pilonidal disease following surgical excision remains controversial, despite an abundance of research into different treatment options. Negative pressure wound therapy is an emerging treatment option for complex or recurrent pilonidal disease. These investigators performed a comprehensive literature search, using the electronic databases MEDLINE, Cochrane library, CINAHL, PubMed, and Web of Knowledge. All studies, case reports, and multiple case series evaluating the use of negative pressure wound therapy for treatment of pilonidal disease were included. Despite the breadth of the search parameters, these researchers identified limited studies addressing this issue; all were published between 2003 and 2007. Findings of 5 case reports or multiple case series tentatively suggested that negative pressure wound therapy may be an emerging treatment option for pilonidal disease management. However, the authors recommended that more rigorous research, including randomized controlled trials, be conducted before implications can be drawn for evidence-based practice.
Danne et al (2017) stated that pilonidal sinus (PS) disease is an inflammatory skin and subcutaneous tissue condition that presents with infection, acute abscess, chronic discharging wounds, and/or pain. Surgery with open healing by secondary intention typically is used to achieve the fastest healing time with minimal recurrence rates. These investigators carried out a retrospective analysis of data extracted from the medical records of 73 consecutive patients who had symptomatic natal cleft PS over a 10-year period to compare use of NPWT to alginate-based/gauze daily dressing (DD) changes in terms of healing time and recurrence. Variables extracted included age, gender, PS wound diameter (small = less than 1 cm, medium = 1 cm to 3 cm, large = greater than 3 cm), and time in weeks to achieving the end-point (epithelialization). Risk factors examined that can affect healing or recurrence of previously operated PS disease included initial drainage before excision and risk factors for impaired healing (morbid obesity as determined by body mass index [BMI] of greater than or equal to 35, chronic infective skin conditions, and ongoing therapy with immuno-modulating drugs or chemotherapy), and loss to follow-up. Data were collected and analyzed using the Chi-squared statistic, Kaplan-Meier curves, and Cox regression models. The total time of follow-up was 390 weeks for the DD group and 311 weeks for NPWT group. Patient mean age was 26.5 ± 10.7 years, most (53, 72.6 %) were male, and 12 (16.4 %) had co-morbidities potentially affecting healing; 9 were treated with primary closure and 62 patients were treated with open healing by secondary intention (2 additional patients receiving DD were excluded from the analysis because they had small sinuses that made NPWT unfeasible). Among participants, 30 (48 %) received DD and 32 had NPWT. The median time to healing was 10 weeks (95 % confidence interval [CI]: 7 to 17) in the DD group and 8 weeks (95 % CI: 7 to 9) in the NPWT group (not significantly different). In patients who healed, the average time to healing was 15.0 ± 18.1 and 9.8 ± 6.3 weeks in the DD and NPWT groups, respectively (not significantly different). The PS wound recurred in 5 patients - 4 (12.5 %) in the DD group and 1 (3.1 %) in the NPWT group (p = 0.355). In univariate analysis, only the presence of co-morbidities was found to significantly affect time to healing (HR 95 %, CI: 0.40 [0.17 to 0.93]; p = 0.033]. The authors concluded that prospective, randomized controlled clinical studies are needed.
de Azevedo et al (2019) noted that pilonidal disease occurs in 26 in 100,000 people, affecting mainly men aged 20 to 30 years. It is treated by a variety of surgical techniques; however, there is a lack of consensus on the optimal choice of treatment for complex pilonidal disease. In addition, there is no consensus regarding care of the wound after surgery; NPWT applied to open wounds following pilonidal disease surgery has been suggested as a way to decrease healing times and costs and is an emerging option for complex and or recurrent pilonidal disease. This study described a case of complex pilonidal disease managed with local excision and NPWT followed by a split-thickness skin graft.
An UpToDate review on “Pilonidal disease” (Johnson, 2020) states that “An alternative method for managing the open wound is the use of negative pressure wound therapy (NPWT), which is perhaps more useful for larger defects. A trial that randomly assigned 49 patients to standard care or NPWT found a slightly improved time to complete wound healing for NPWT compared with standard therapy (84 versus 93 days). There were no differences in visual analog pain scores or recurrence rates between the groups. Practical issues with the application of the dressing and device may limit its use in this setting”.
Furthermore, an UpToDate review on “Negative pressure wound therapy” (Gestring, 2020) does not mention pilonidal disease as an indication for NPWT.
Portable Device for NPWT (PICO)
In a randomized, multi-center, phase-IV study, Kirsner et al (2019) compared for non-inferiority the percentage change in target ulcer dimensions (area, depth, and volume) of a single-use negative pressure wound therapy (s-NPWT) system versus traditional NPWT (t-NPWT) in patients with venous leg ulcers (VLUs) or diabetic foot ulcers (DFUs) over a 12-week treatment period or up to confirmed healing. Baseline values were taken at the randomization visit. Randomized by wound type and size, a total of 164 patients with non-infected DFUs and VLUs were included. The intention-to -treat (ITT) population was composed of 161 patients (101 with VLUs, 60 with DFUs) and 115 patients completed follow-up (64 in the s-NPWT group and 51 in the t-NPWT group) (PP population). The average age for all patients was 61.5 years, 36.6 % were women, and treatment groups were statistically similar at baseline. Primary endpoint analyses on wound area reduction demonstrated statistically significant reduction in favor of s-NPWT (p = 0.003) for the PP population and for the ITT population (p < 0.001). Changes in wound depth (p = 0.018) and volume (p = 0.013) were also better with s-NPWT. Faster wound closure was observed with s-NPWT (Cox proportional hazards ratio (0.493 (0.273, 0.891); p = 0.019) in the ITT population. Wound closure occurred in 45 % of patients in the s-NPWT group versus 22.2 % of patients in the t-NPWT group (p = 0.002). Median estimate of the time to wound closure was 77 days for s-NPWT. No estimate could be provided for t-NPWT due to the low number of patients achieving wound closure. Device-related adverse events (AEs) were more frequent in the t-NPWT group (41 AEs from 29 patients) than in the s-NPWT group (16 AEs from 12 patients). The s-NPWT system met non-inferiority and achieved statistical superiority versus t-NPWT in terms of wound progression toward healing over the treatment period. The authors concluded that when appropriate standard of care has not been successful, and NPWT is being considered for the management of challenging or stalled DFUs or VLUs, s‐NPWT (PICO) should be considered a 1st choice over other types of NPWT.
Kirsner et al (2020) determined the cost-effectiveness of s-NPWT compared with t-NPWT for the treatment of VLUs and DFUs in the U.S. These researchers employed a Markov decision-analytic model to compare the incremental cost and ulcer weeks avoided for a time horizon of 12 and 26 weeks using lower extremity ulcer closure rates from a published randomized controlled trial (RCT; n = 161) that compared s-NPWT with t-NPWT. Treatment costs were extracted from a retrospective cost-minimization study of s-NPWT and t-NPWT from the payer perspective using U.S. national 2016 Medicare claims data inflated to 2018 costs and multiplied by 7 to estimate the weekly costs of treatment for s-NPWT and t-NPWT; 2 arms of the model, t-NPWT and s-NPWT, were calculated separately for a combination of both VLU and DFU ulcer types. In this model, a hypothetical cohort of patients began in the open ulcer health state, and at the end of each weekly cycle a proportion of the cohort moved into the closed ulcer health state according to a constant transition probability. The costs over the defined time scale were summed to give a total cost of treatment for each arm of the model, and then the difference between the arms was calculated. Effectiveness was calculated by noting the incidence of healing at 12 and 26 weeks and the total number of open ulcer weeks; the incremental effectiveness was calculated as s-NPWT effectiveness minus t-NPWT effectiveness. Data were extracted to Excel spreadsheets and subjected to 1-way sensitivity, scenario (where patients with unhealed ulcers were changed to standard care at 4 or 12 weeks), probabilistic, and threshold analyses. S-NPWT was found to provide an expected cost saving of $7,756 per patient and an expected reduction of 1.67 open ulcer weeks per patient over 12 weeks and a cost reduction of $15,749 and 5.31 open ulcer weeks over 26 weeks. Probabilistic analysis at 26 weeks showed 99.8 % of the simulations resulted in s-NPWT dominating t-NPWT. Scenario analyses showed that s-NPWT remained dominant over t-NPWT (cost reductions over 26 weeks of $2,536 and $7,976 per patient, respectively). The authors concluded that these results suggested that, where appropriate, s-NPWT should be considered as a cost-effective alternative to t-NPWT and may provide an opportunity for policymakers to reduce the economic burden of lower extremity ulcers..
The authors stated that this study had several drawbacks. First, the assumptions made for effectiveness reflect data from only 1 RCT. Second, the weekly costs of both treatments were from 1 cost-minimization analysis, albeit using data from a large number of patients. These researchers tried to address these limitations by carrying out sensitivity analyses; however, as further clinical and cost studies emerge, updated economic evaluations should be conducted. Real-world observational studies reporting both clinical and economic data would be particularly useful. Finally, this evaluation took the payer perspective; evaluations from different stakeholder perspectives may also be important, including cost-effectiveness from the home health perspective.
Wilkinson et al (2021) noted that NPWT is a widely used treatment for chronic, non-healing wounds. Surprisingly, few studies have systematically evaluated the cellular and molecular effects of negative pressure treatment on human skin. Furthermore, no study to-date has directly compared recently available s-NPWT modalities to t-NPWT devices in a controlled setting. These researchers developed a novel large-scale ex-vivo human skin culture system to effectively examine the efficacy of 2 different NPWT modalities; s-NPWT devices were applied to human ex-vivo wounded skin sheets cultured over a period of 48 hours. Cellular tissue response to therapy was evaluated via a combination of histological analysis and transcriptional profiling, in samples collected from the wound edge, skin adjacent to the wound, and an extended skin region. S-NPWT caused less damage to wound edge tissue than traditional application, demonstrated by improved skin barrier, reduced dermal-epidermal junction disruption and a dampened damage response. Transcriptional profiling confirmed significantly less activation of multiple pro-inflammatory markers in wound edge skin treated with s-NPWT versus t-NPWT. The authors concluded that these ex-vivo findings suggested that s-NPWT beneficially altered multiple aspects of wound edge physiology versus t-NPWT, and this may confer improved clinical efficacy. These researchers noted that a drawback of this study was the difference in absolute negative pressure delivered by the 2 devices. Moreover, these investigators stated that further in‐depth studies are needed to fully elucidate s-NPWT's cellular mode(s) of action.
Brownhill et al (2021) stated that t-NPWT systems can be large and cumbersome, limiting patient mobility and adversely affecting QOL. PICO, a no canister single-use system, offers a lightweight, portable alternative to t-NPWT, with improved clinical performance. These researchers examined the potential mechanism(s) of action of s-NPWT versus t-NPWT. S-NPWT and t-NPWT were applied to an in-vivo porcine excisional wound model, following product use guidelines. Macroscopic, histological, and biochemical analyses were carried out at defined healing time points to evaluate multiple aspects of the healing response. Wounds treated with s-NPWT displayed greater wound closure and increased re-epithelialization versus those treated with t-NPWT. The resulting granulation tissue was more advanced with fewer neutrophils, reduced inflammatory markers, more mature collagen, and no wound filler-associated foreign body reactions. Of note, s-NPWT failed to induce wound edge epithelial hyper-proliferation, while t-NPWT compromised peri-wound skin, which remained inflamed with high trans-epidermal water loss; features not observed following s-NPWT; s-NPWT was identified to improve multiple aspects of healing versus t-NPWT. The authors concluded that the findings of this study provided important new insight into the differing mode of action of s-NPWT versus t-NPWT and may go some way to explaining the improved clinical outcomes observed with s-NPWT.
These researchers stated that the findings of this study suggested that s-NPWT independently promoted granulation tissue maturation and re-epithelialization. Indeed, these 2 aspects could be closely linked, with a mature wound bed important to permit active re-epithelialization. Data now show a direct link between compromised skin barrier and subsequent wound recurrence, a significant consideration for chronic wound management. These investigators stated that although several clinical studies have demonstrated enhanced wound closure and faster granulation with t-NPWT, few studies have performed follow-up assessments to determine rates of wound recurrence. They stated that a future pre-clinical in-vivo investigation would provide a unique opportunity to examine recurrence, an important and often overlooked aspect of wound healing studies.
Kirsner and Hurd (2020) stated that NPWT has evolved beyond its original design as a stationary, reusable system (t-NPWT) and is now also available as a s-NPWT. No established guidance exists for selecting the appropriate system to treat specific wound types in various settings. These investigators reviewed the current practice and challenges associated with NPWT. Relevant literature was examined to provide a background on current practice. An online quantitative survey was carried out during October and November 2018 among users of NPWT based in acute care settings across 6 countries (Australia, France, Germany, Italy, the U.K, and the U.S.) to elucidate the operational and financial components considered in determining and/or thwarting efficacious use of NPWT. Data from recruited participants were collected, analyzed, and tabulated by an independent research company. All findings were reported as numbers/percentages. Wound size and depth, as well as the amount and/or type of exudate, were found to be among key factors in selecting NPWT; patient quality of life (QOL) in terms of mobility, independence, and attitude toward treatment may be factors in adherence with prescribed care. Clinicians were not consistently knowledgeable regarding the financial and operational challenges of utilization presented by large fleets of NPWT pumps, nor were other institutional employees such as payers and discharge planners. The authors concluded that evidence-based recommendations are needed to guide decisions regarding NPWT systems, which in turn may improve therapy implementation, access to care, and patient QOL, while driving operational and financial efficiencies for health care providers.
Hurd et al (2021) stated that currently, there are no international standardized guidelines or recommendations to guide the clinical decision-making process on when to initiate various NPWT systems for acute and chronic wounds. Specifically, no established recommendations or guidance exists regarding the type of NPWT system to use, traditional (tNPWT) or single-use (sNPWT), and how to transition between the 2 systems. An expert panel was convened to provide recommendations to clinicians on when to consider NPWT use in acute and chronic wound management; and develop a practical decision-making tool to guide the appropriateness of the different NPWT modalities (tNPWT or sNPWT) and when they should be used. The panel made recommendations and designed a clinical decision-making tool to aid the consideration for initiating NPWT and the optimal system to be used based on therapeutic goals, wound-related factors, patient satisfaction and quality of life, care setting-related factors, economic-related factors, and NPWT system-related factors. The authors concluded that the panel recommendations took into consideration the clinical, operational, and financial factors in the clinical decision-making process of NPWT use to enable optimal patient and health care system outcomes. The panel provided the following recommendations regarding sNPWT:
- Consensus Statement 4 noted that “sNPWT can be considered as a bolster dressing for wounds in which closure is being obtained via a split-thickness skin graft (STSG) or application of a skin substitute”.
- Consensus Statement 6 noted that “When NPWT is deemed an appropriate treatment modality for acute and chronic wounds, sNPWT should be the first-line modality utilized to increase patient satisfaction and quality of life. Patient education on NPWT as a treatment modality, the benefits of its use, and the advantages of sNPWT over tNPWT can improve patient satisfaction and treatment compliance”.
- Consensus Statement 7 noted that “sNPWT use may be an optimal choice for ambulatory patients with wounds eligible for sNPWT use who must return to work or face barriers to access follow-up medical appointments”.
- Consensus Statement 8 noted that “tNPWT is a valuable treatment option for patients with acute or chronic wounds that are large and complex. Benefits of tNPWT include stabilization of the wound and patient, patient mobility, more rapid transition from critical care units to step-down units, and reduced hospital length of stay. Initial use of sNPWT or early conversion to sNPWT from tNPWT in eligible wounds should be considered to assist in transitioning patients from inpatient to outpatient care”.
It is interesting to note that the total number of panel members was not mentioned in the article; and their votes on the consensus statements were not disclosed (i.e., the percentage of panel members who voted for yes/no/abstain). It should also be noted that the authors of this article are consultants for Smith+Nephew; and Smith+Nephew provided financial support for convening the consensus panel and provided editorial support during the preparation of this manuscript.
Saunders et al (2021) noted that surgical-site complications (SSCs) remain a significant cause of morbidity and mortality, particularly in high-risk patients. In a systematic review and meta-analysis, these researchers examined if prophylactic use of a specific sNPWT device could reduce the incidence of SSCs after closed surgical incisions compared with conventional dressings. They carried out a systematic literature review using Medline, Embase and the Cochrane Library to identify articles published from January 2011 to August 2018; RCTs and observational studies comparing PICO sNPWT with conventional dressings, with at least 10 patients in each treatment arm, were included. Meta-analyses were performed to determine ORs or MDs, as appropriate; PRISMA guidelines were followed. The primary outcome was surgical-site infection (SSI); secondary outcomes were other SSCs and hospital efficiencies. Risk of bias was assessed. Of 6197 citations screened, 29 studies enrolling 5,614 patients were included in the review; all studies included patients with risk factors for SSCs. sNPWT reduced the number of SSIs (OR 0.37, 95 % CI: 0.28 to 0.50; number needed to treat (NNT) = 20). sNPWT reduced the odds of wound dehiscence (OR 0.70, 95 % CI: 0.53 to 0.92; NNT = 26), seroma (OR 0.23, 95 % CI: 0.11 to 0.45; NNT = 13) and necrosis (OR 0.11, 95 % CI: 0.03 to 0.39; NNT = 12). Mean length of hospital stay was shorter in patients who underwent sNPWT (MD -1.75, 95 % CI: -2.69 to -0.81). The authors concluded that the use of the sNPWT device in patients with risk factors reduced the incidence of SSCs and the mean length of hospital stay. These investigators stated that the findings of this analysis suggested that this technology warrants consideration by policy-makers and healthcare professionals to optimize post-surgical wound treatment pathways, to ensure that all patients have the best treatment while making effective use of scarce healthcare resources.
The authors stated that the bias assessment performed revealed some potential sources of bias that should be considered. In most cases it was not possible to blind the patient and treating clinician to treatment assignment, owing to the nature of the device. The use of a sham device could have been possible; and was considered by the authors of some studies; however, it would likely still be apparent which treatment a patient had been assigned to. An alternative way to overcome this could be to ensure an independent and blinded assessor for the reporting of wound outcomes specifically. The majority of the studies, however, did not specify whether this was the case. The lack of intention-to-treat (ITT) analyses in some of the studies may have led to attrition bias. A further drawback of the data was that some of the studies included had small sample sizes.
Furthermore, an UpToDate review on “Negative pressure wound therapy” (Gestring, 2021) does not mention single-use negative pressure wound therapy / PICO.
Prophylactic NPWT for the Prevention of Surgical Site Infection After Abdominal Surgery
Meyer and colleagues (2021a) stated that prevention of surgical site infection (SSI) is a public health challenge. In a systematic review and meta-analysis, these researchers examined if prophylactic NPWT (pNPWT) allows prevention of SSI following laparotomy. Medline, Embase and Web of Science were searched on the 06.10.2019 for original studies reporting the incidences of SSI in patients undergoing open abdominal surgery with and without pNPWT. Risk difference (RD) between control and pNPWT patients and RR for SSI were obtained using random effects models. A total of 21 studies (2,930 patients, 5 RCT, 16 observational studies) were retained for the analysis. Pooled RD between patients with and without pNPWT was -12 % (95 % CI: -17 % to -8 %, I2: 54 %, p < 0.00001) in favor of pNPWT. That RD was -12 % (95 % CI: -22 % to -1 %, I2 : 69%, p = 0.03) when pooling only RCT (792 patients). pNPWT was protective against the incidence of SSI with a RR of 0.53 (95 % CI: 0.40 to 0.71, I2: 56 %, p < 0.0001). The effect on pNPWT was more pronounced in studies with an incidence of SSI greater than or equal to 20 % in the control arm. The preventive effect of pNPWT on SSI remained after correction for potential publication bias; however, when pooling only high-quality observational studies (642 patients) or RCT (527 patients), significance was lost. The authors concluded that existing studies suggested that pNPWT on closed wounds was protective against the occurrence of SSI in abdominal surgery; however, these findings need to be confirmed by more high quality evidence, preferentially in subgroups of patients with an incidence of SSI greater than or equal to 20 % in the control arm.
Meyer and associates (2021b) noted that closed perineal wounds often fail to heal by primary intention following abdominal-perineal resection (APR) and are often complicated by SSI and/or wound dehiscence. Recent evidence showed encouraging results of pNPWT for prevention of wound-related complications in surgery. In a systematic review, these researchers examined the early existing evidence regarding the use of pNPWT for the prevention of wound-related complications on perineal wounds following APR. Medline, Embase, and Web of Science were searched for original publications and congress abstracts reporting the use of pNPWT after APR on closed perineal wounds. A total of 7 studies were included for analysis; 2 reported significantly lower incidence of SSI in pNPWT patients than in controls with a risk reduction of about 25 % to 30 %; 2 other publications described similar incidences of SSI between the 2 groups of patients, but described SSI in pNPWT patients to be less severe; 1 study reported significantly lower incidence of wound dehiscence in pNPWT patients than in controls. The authors concluded that the largest non-randomized studies examining the effect of pNPWT on the prevention of wound-related complications following APR showed encouraging results in terms of reduction of SSI and wound dehiscence that deserve further investigation and confirmation.
Wound Vac for the Treatment of Full Thickness Burns
Chen et al (2005) examined the effects of vacuum-assisted closure (VAC) on starting the process of wound healing and decreasing apoptosis. These researchers examined the variations in expression of proto-oncogenes c-myc, c-jun and Bcl-2 in pig wound model with acute full-thickness skin defect and human chronic wounds by immunohistochemistry, calculated the numbers of expressive positive cells and the labelling index (LI), and observe the process of wound healing. In pig experiment, the wound in experimental group was very clean and without obvious exudates, many neo-epiderm and granulation tissue rapidly appeared or formed after 6 days; and healed completely by the 25th day. On the contrary, in the wound of control group, more exudates and blood crust could be seen and fewer neo-epiderm and granulation tissue appeared after 6 days and was healed by 30th day. Immediately after the wound was created, the expression of c-myc, c-jun and Bcl-2 was lower and mainly situated in nucleus or cytoplasma of the basilar cells. After the wound was created in control group, or after starting the VAC treatment in experimental group, their expression rapidly and obviously increased, the distribution of the positive cells also became enlarged, but the amount of expression decreased rapidly after the expressive peak have reached. In the successive 12 days following the wound was created, the expression of c-myc, c-jun and Bcl-2 in the experimental group was constantly higher than that of the control group. In human chronic wounds, there wasn't obvious secretions, and healthier granulation tissue was rapidly formed after VAC treatment. The expression of c-jun was mainly located in cytoplasma of basilar cells of epithelium, dermal fibroblasts and inflammatory cells, and the positive cell and labelling index obviously decreased. The expression of c-myc and Bcl-2 was mainly in cytoplasma of basilar cells, but the amount of expression and the labelling index became obviously increased after VAC treatment. The authors concluded that VAC could rapidly start the healing course of the pig' s acute skin wound and human chronic wound, decrease apoptosis of the reparative cells, so as to accelerate wound healing.
Lohana and Hogg (2010) stated that the advent of VAC devices has changed many wound management practices by application of topical negative pressure. These investigators presented the case of a 20-year old man who sustained 21 % total body surface area (BSA) circumferential full-thickness burns to both legs from knees to feet. The VAC dressing was used in the management of his wounds. The patient had persistent pyrexia and graft destruction and subsequently the wounds cultured Aspergillus fumigatus. The increasing popularity of the VAC dressing was well deserved in the management of complex burn wounds. This case highlighted the fact that in the care of complex burn patients the development of opportunistic infections should be considered, especially in situations such as persistent pyrexia or following the breakdown of healed grafts, especially during the use of topical negative pressure.
Kamolz et al (2014) noted that over the last 50 years, the evolution of burn care has led to a significant decrease in mortality. The biggest impact on survival has been the change in the approach to burn surgery. Early excision and grafting has become a standard of care for the majority of patients with deep burns; the survival of a given patient suffering from major burns is invariably linked to the take rate and survival of skin grafts. The application of topical negative pressure (TNP) therapy devices has demonstrated improved graft take in comparison to conventional dressing methods alone. These investigators analyzed the impact of TNP therapy on skin graft fixation in large burns. In all patients, these researchers applied TNP dressings covering a percent total BSA (%TBSA) of greater than 25. The following parameters were recorded and documented using BurnCase 3D: age, gender, %TBSA, burn depth, hospital length-of-stay (LOS), Baux score, survival, as well as duration and incidence of TNP dressings. After a burn depth adapted wound debridement, coverage was simultaneously performed using split-thickness skin grafts, which were fixed with staples and covered with fatty gauzes and TNP foam. The TNP foam was again fixed with staples to prevent displacement and finally covered with the supplied transparent adhesive film. A continuous sub-atmospheric pressure between 75 to 120 mm Hg was applied (VAC, KCI, Vienna, Austria). The 1st dressing change was performed on day 4; 36 out of 37 patients, suffering from full thickness burns, were discharged with complete wound closure; only 1 patient succumbed to their injuries. The overall skin graft take rate was over 95 %. The authors concluded that split thickness skin graft fixation by TNP was an efficient method in major burns, notably in areas with irregular wound surfaces or subject to movement (e.g., joint proximity), and was worth considering for the treatment of aged patients.
Nguyen et al (2015) stated that negative pressure wound therapy (NPWT) has revolutionized the management of complicated wounds and has contributed an additional modality for securing split thickness skin grafts (STSG). The standard for NPWT is the VAC device. The authors' institution has accumulated experience using standard gauze sealed with an occlusive dressing and wall suction (GSUC) as their primary mode for NPWT. The authors reported a randomized controlled trial (RCT) comparing the efficacy of the GSUC versus the VAC in securing STSG. A prospective RCT was conducted in 157 wounds in 104 patients requiring STSG from August 2009 to July 2012. All wounds were randomized to VAC or GSUC treatment and assessed for skin graft adherence/take. At post-operative day 4 or 5, NPWT was discontinued, and the size of the graft and any non-adherent areas were measured and recorded. Concomitant co-morbidities, wound location, etiology, study failures, and re-operative rates were also reviewed. In all, 77 and 80 wounds were randomized to the GSUC and VAC study arms. Patient demographics were similar between both groups in terms of age, sex, co-morbidities, etiology, and wound location. In all, 64 of 80 wounds in the GSUC group and 60 of 77 wounds in the VAC group had full take of the skin graft by post-operative day 4 or 5 (p = 0.80). The mean % take rate in the GSUC group was 96.12 % versus 96.21 % in the VAC arm (p = 0.98). The authors concluded that the use of NPWT in securing STSG was a useful method to promote adherence and healing. This study demonstrated that a low-cost, readily accessible system utilizing GSUC resulted in comparable skin graft take in comparison to the VAC device.
Furthermore, UpToDate reviews on “Emergency care of moderate and severe thermal burns in adults” (Rice and Orgill, 2021) and “Overview of burn injury in older patients” (Pham, 2021) do not mention vacuum-assisted closure (VAC) / negative pressure wound therapy (NPWT) as a management / therapeutic option.
Donor-Site Closure in Radial Forearm Free Flap
Shimada and colleagues (2022) noted that several studies have reported the use of NPWT improved skin graft failure in the forearm flap donor site. In a systematic review, these investigators examined the effectiveness of NPWT with skin graft for donor-site closure in radial forearm free flap (RFFF) reconstruction. They carried out a systematic search in PubMed, Web of Science, and Cochrane Library databases. The search terms used for PubMed were ([radial forearm]) AND ([donor]) AND ([negative pressure or vacuum]). This review was registered in the International Prospective Register of Systematic Reviews and performed in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement. A total of 3 prospective RCTs and 3 retrospective comparative studies were included. Compared with conventional bolster dressing, the use of NPWT dressing did not lead to significant improvements in partial skin graft loss, tendon exposure, and other complications. NPWT improved hand functionality earlier; nonetheless, the cost of the device and dressings was a disadvantage. The authors concluded that the use of NPWT for skin graft fixation in the RFFF donor site is not generally recommended.
Fingertip Replantation
Hu and colleagues (2022) fingertip replantation is technically challenging. Venous congestion is one of the most common causes of replantation failure; thus, various venous drainage procedures and salvage techniques have been used in the treatment of venous congestion. NPWT has proven beneficial in limb injuries, yet limited studies of fingertip replantation exist. In a systematic review, these investigators evaluated risk factors in fingertip replantation and examined the feasibility and clinical benefits of NPWT compared with other salvage techniques. From January of 2015 to December of 2019, 27 patients (27 digits) who experienced fingertip amputation over Tamai zone I or II underwent replantation. Salvage NPWT was used for venous congestion post-operatively. Replantation data were collected for further analysis. The overall survival rate of digit replantation with salvage NPWT was 92.6 % (25/27). The blood transfusion rate was 11.1 % (3/27). The average hospitalization time was 8.04 ± 1.43 days and the median duration of NPWT was 6 days (range of 4 to 8 days; inter-quartile range [IQR] of 2 days). There was no significant difference between the survival and failure groups for all risk factors evaluated. The authors concluded that NPWT was a simple and effective salvage option to relieve venous congestion in fingertip replantation with a satisfactory survival rate, low blood transfusion rate, and short inpatient stay. Level of Evidence = IV.
The authors stated that this review had several drawbacks. First, the blood loss was under-estimated. These investigators measured the amount of blood from the suction bottle as patients’ blood loss; however, some blood could be absorbed in the gauze and did not flow into the bottle, which led to the under-estimation of blood loss from patients. Therefore, these researchers will weigh gauze in the future to prevent the under-estimation of blood loss. Second, the appropriate negative pressure of NPWT for fingertip replantation is still under debate, and the effects of NPWT on the site of blood vessel anastomosis were unclear. Too much negative pressure causes excessive bleeding and compressed anastomosis may result in circulation compromise; therefore, NPWT must be used with caution following fingertip replantation; it is necessary to establish the standard negative pressure for fingertip replantation. Third, these researchers monitored the replanted digit only by means of an observational window, which is subjective and can be doubtful; thus, they will introduce laser Doppler, which provides more detailed data to evaluate vessels’ viability and blood circulation in the fingertips.
Following Total Joint (e.g., Hip and Knee) Arthroplasty
Newman and co-workers (2019) stated that continuous wound drainage after arthroplasty can lead to the development of a peri-prosthetic joint infection. Closed incisional NPWT (ciNPWT) has been reported to aid in alleviating drainage and other wound complications. In a prospective, single-center RCT, these researchers compared the use of ciNPWT with standard of care (SOC) dressing in revision arthroplasty patients who were at high risk to develop wound complications. A total of 160 patients undergoing elective revision arthroplasty were prospectively randomized to receive either ciNPWT or a silver-impregnated occlusive dressing after surgery. Patients were included if they had at least 1 risk factor for developing wound complication(s): wound complication, re-admission, and re-operation rates were collected at 2, 4, and 12 weeks post-operatively. The post-operative wound complication rate was significantly higher in the control cohort compared to the ciNPWT cohort (19 [23.8% ] versus 8 [10.1 %], p = 0.022). There was no significant difference between the control and ciNPWT cohorts in terms of re-admissions (19 [23.8 %] versus 16 [20.3 %], p = 0.595). Re-operation rate was higher in controls compared to ciNPWT patients (10 [12.5 %] versus 2 [2.5 %], p = 0.017). After adjusting for the history of a prior peri-prosthetic joint infection and inflammatory arthritis, the ciNPWT cohort had a significantly decreased wound complication rate (OR 0.28, 95 % CI: 0.11 to 0.68). The authors concluded that the findings of this study demonstrated that high risk patients may benefit from ciNPWT in terms of reducing the rate of wound complications, SSIs, and re-operations following revision total hip arthroplasty (THA) and total knee arthroplasty (TKA). Moreover, these researchers stated that future studies should include multi-center clinical trials to further strengthen the results found in this study; in addition, a cost-benefit analysis would be useful.
The authors stated that this study had several drawbacks. Not all patients had the ciNPWT in place for the same amount of time (mean of 3.6 days, range of 2 to 15). Moreover, the ciNPWT device was only used during the hospital stay and was removed before discharge. There were multiple surgeons who participated in this study, which could lead to heterogeneity among the cases; however, no significant peri-operative differences between the 2 groups were identified in this study. Although this study was a prospective RCT, there are some differences between the 2 groups in terms of 2 of the inclusion criteria. Despite this, since this study was a randomized trial, there was some protection against confounding built-in by the study design, and this study used multi-variable regression modeling to control for any statistical bias that could potentially affect the outcomes.
In a systematic review and meta-analysis, Kim and Lee (2020) determined the effective indications of ciNPWT following THA or TKA. These investigators carried out a systematic search on Medline, Embase, and Cochrane Library, and 11 studies were included. The studies comparing between ciNPWT and conventional dressings were categorized into following subgroups based on patient risk and revision procedures: routine versus high-risk patient; primary versus revision arthroplasty. Pooled estimates were calculated for wound complication and SSI rates in the subgroup analyses using Review Manager. In high-risk patients, the overall rates of wound complication (OR = 0.38; 95 % CI: 0.15 to 0.93; p = 0.030) and SSI (OR = 0.24; 95 % CI: 0.09 to 0.64; p = 0.005) were significantly lower in the ciNPWT; however, there were no differences in routine patients. In cases involving revision arthroplasties, the overall rates of wound complication (OR = 0.33; 95 % CI: 0.18 to 0.62; p < 0.001) and SSI (OR = 0.26; 95 % CI: 0.11 to 0.66; p = 0.004) were significantly lower in the ciNPWT; however, there were no differences in cases involving primary arthroplasties. The authors concluded that these findings suggested that ciNPWT should be considered for high‐risk patients and in revision procedures for wound management following THA or TKA
The authors stated that this study had several drawbacks. First, the heterogeneity of the demographic data among included studies, including differences in age, sex distribution, as well as differences in follow‐up duration, may be potential confounding factors. However, the meta‐regression analysis showed that age, sex distribution, BMI, and follow‐up were not significantly associated with rates of wound complication and SSI. Although surveillance for the first 12 months following THA and TKA is recommended, only 3 included studies had more than 12 months of follow‐up. However, wound‐related SSI is likely to occur in the acute setting; and a follow‐up duration of less than 12 months might be acceptable to examine the effectiveness of the ciNPWT system on wound management. Second, studies differing in the indication of patient co-morbidities might include selection bias. Although a small difference in the specific indication of co-morbidities might be a potential selection bias, the details of the indication had a similarity among the included studies of high‐risk patients. Third, included studies were fewer in subgroups of high‐risk patients and revision arthroplasty than in the subgroups of routine patients and primary arthroplasty, which might include confounding factors. Finally, these researchers could not conduct a cost‐effectiveness analysis of the ciNPWT system because of a lack of published studies.
Ailaney and colleagues (2021) noted that persistent wound drainage following total joint arthroplasty (TJA) increases the risk of SSIs. While ciNPWT decreases infections in traumatic wounds, evidence for its use following elective TJA is limited. In a meta-analysis, these researchers examined the effect of ciNPWT on risk of SSI and wound complications following TJA. Medline, Embase, CINAHL, and Cochrane Library were searched for RCTs comparing ciNPWT versus standard dressings following THA and TKA. Studies exclusively involving THA for femoral neck fractures were excluded. Risk of SSI and non-infectious wound complications (blisters, seroma, hematoma, persistent drainage, dehiscence, and wound edge necrosis) following TJA were analyzed. SSI risk was lower with ciNPWT compared to standard dressings (3.4 % versus 7 %; RR 0.48, p = 0.007), specifically in revision THA and TKA (4.1 % versus 10.5 %; RR 0.41, p = 0.03). ciNPWT increased the non-infectious complication risk after primary TKA (RR 4.71, p < 0.0001), especially causing wound blistering (RR 12.66, p < 0.0001). ciNPWT decreased hospital LOS by 0.73 days (p = 0.04) and re-operation rate (RR 0.28, p = 0.01). The authors concluded that ciNPWT decreased SSI risk compared to standard dressings after revision TJA, but not primary TJA. ciNPWT was associated with greater than 12-fold increased risk of wound blistering following primary TKA. These researchers stated that ciNPWT may play a role in revision TJA management; however, additional RCTs with uniform wound assessment methods must be carried out to sufficiently power findings and draw conclusions regarding the use of ciNPWT following primary TJA.
Fracture-Related Infections Following Internal Osteosynthesis of the Extremity
In a systematic review, Jensen and colleagues (2021) examined the current literature on studies using NPWT or dressings following fracture-related infection (FRI) in internal osteosynthesis of the extremity. Studies were analyzed on fracture and wound healing and included when comparing or describing the use of either NPWT or dressings in FRI. These investigators carried out a systematic literature search in 4 electronic databases: Embase, Medline, the Cochrane Library, and Scopus. The studies were screened by 2 authors using Covidence.org and evaluated for risk of bias. A total of 8,576 records were identified. No articles compared NPWT to dressings; 7 case reports and 3 case series included a total of 115 patients treated for FRI. Fracture healing was achieved in 21 out of 67 patients treated with NPWT (4 amputations and 46 not described) and all 48 patients in the dressing group (4 patients needed additional sequestrectomy procedures); 5 studies did not describe fracture healing. In 57 out of 67 patients treated with NPWT, the wounds were described as healed, closed, or requiring soft tissue reconstruction (4 amputations and 6 lacking description). The dressing group had complete wound coverage in 18 patients and partial coverage in 30 patients. Studies were generally at high risk of bias because of insufficient descriptions of both patient demographics and outcomes. No studies compared NPWT to dressings, and the existing literature is at high risk of bias. The authors concluded that the included studies were of low-level evidence; and NPWT could neither be recommended nor advised against to cover infected osteosynthesis.
Haidari and associates (2021) noted that FRI is a severe musculoskeletal complication in orthopedic trauma surgery, causing challenges in bony and soft tissue management. Currently, NPWT is used in cases of FRI; however, controversy exists regarding the impact of NPWT on the outcome in FRI, especially on infection recurrence. In a systematic review, these investigators examined the literature on the role of NPWT in the management of FRI. They carried out a literature search of the PubMed, Embase, and Web of Science database. Studies that reported on infection recurrence related to FRI management combined with NPWT were eligible for inclusion. Quality assessment was performed using the PRISMA statement and the Newcastle-Ottawa Quality Assessment Scale. After screening and quality assessment of 775 unique identified records, 8 studies could be included for qualitative synthesis. All 8 reported on infection recurrence, which ranged from 2.8 % to 34.9 %; 6 studies described wound healing time, varying from 2 to 7 weeks; 4 studies took repeated microbial swabs during subsequent vacuum dressing changes; 1 study reported newly detected pathogens in 23 % of the included patients, and 3 studies did not find new pathogens. The authors concluded that this review provided an evaluation of current literature on the role of NPWT in the management of soft tissue defects in patients with FRI. Due to the lack of uniformity in included studies, conclusions should be drawn with caution. Currently, there is no clear scientific evidence to support the use of NPWT as definitive treatment in FRI. At this stage, these researchers could only recommend early soft tissue coverage (within days) with a local or free flap. They stated that NPWT may be safe for a few days as temporarily soft tissue coverage until definitive soft tissue management could be performed; however, comparative studies between NPWT and early wound closure in FRI patients are needed.
The authors stated that the main disadvantage of this systematic review was the limited number of high-quality studies on FRI treatment with NPWT. In addition, there was a lack of uniformity in NPWT use and additional treatment, final wound closure, and measured outcomes between the included studies. Furthermore, included studies sampled with swabs and the total number of patients were low while the variation between studies was wide; thus, this review could only provide limited evidence.
Prevention and Management of Complications from Prosthetic Breast Reconstruction
Chicco and colleagues (2021) stated that complications from prosthetic breast reconstruction are distressing for patients, and their management is challenging. For decades, NPWT has been successfully used for the closure of complex wounds. In a systematic review and meta-analysis, these investigators examined the outcomes of NPWT use in the prevention and management of complications from prosthetic breast reconstruction. They carried out a systematic search of studies published until August 2020 using the PubMed/Medline, Embase, and Ebscohost/CINAHL databases and using the following key words: "negative-pressure wound therapy", "breast reconstruction" and "prosthesis" (including breast implants and tissue expanders). Analyzed endpoints were outcomes of NPWT use in prosthetic breast reconstruction compared with conventional dressings. The methodological quality of included studies was assessed independently. Comparative studies were further meta-analyzed to obtain pooled ORs describing the effectiveness of NPWT in prosthetic breast reconstruction. A total of 10 studies were included with a total of 787 patients (1,230 breasts) undergoing prosthetic breast reconstruction with breast implants or tissue expanders; 3 case-control studies focused on preventing breast wound complications. The meta-analysis of the 3 studies included 502 breasts receiving NPWT and 698 breasts receiving conventional wound care. The meta-analysis favored NPWT for less mastectomy flap necrosis (5.6 % versus 14.3 %; OR, 0.46; 95 % CI: 0.27 to 0.77; p = 0.004; I2 = 0 %) and less overall wound complications (10.6 % versus 21.1 %; OR, 0.49; 95 % CI: 0.35 to 0.70; p < 0.00001; I2 = 0 %). In the management of nipple-areolar complex venous congestion, 1 case report demonstrated 85 % rescue of nipple-areolar complex after using NPWT (-75 mm Hg) for a total of 12 days. In the management of peri-prosthetic infections, 2 case series used NPWT with instillation. It accelerated the treatment of infection and maintained the breast cavity for future reconstruction. Conventional NPWT also showed good salvage outcome in 4 studies. The authors concluded that current evidence suggests that prophylactic use of NPWT in prosthetic breast reconstruction reduces the rate of overall wound complications and mastectomy flap necrosis. In the management of complications from prosthetic breast reconstructions, NPWT may be a promising option showing beneficial results. Moreover, these researchers stated that additional high-quality trials are needed to corroborate the findings of this systematic review.
Negative Pressure Wound Therapy in Split-Thickness Skin Grafting
Yin et al (2018) noted that split-thickness skin grafts (STSGs) are widely used in reconstruction of large skin defects. Conventional therapy causes pain during dressing changing. NPWT is an alternative method to cover the wound bed. In a meta-analysis, these investigators compared the clinical outcomes of negative-pressure wound therapy (NPWT) versus conventional therapy on split-thickness skin after grafting surgery. The PubMed, Embase, and Cochrane databases were searched for randomized controlled trials (RCTs) or cohort studies for articles published between 1993 and April 2017 comparing NPWT to conventional wound therapy for split-thickness skin grafts. The rate of graft take was the primary outcome of this meta-analysis. Wound infection and re-operation rate of the wound were secondary outcomes. Data analysis was conducted using the Review Manager 5.3 software. A total of 5 cohort studies and 7 RCTs including 653 patients were eligible for inclusion. Patients treated with NPWT had a significantly higher rate of graft take compared to those treated with conventional therapy (MD = 7.02; 95 % CI: 3.74 to 10.31; p = 0.00). NPWT was associated with a reduction in re-operation (RR = 0.28; 95 % CI: 0.14 to 0.55; p = 0.00). The reduction in wound infection was not significant (RR = 0.63; 95 % CI: 0.31 to 1.27; p = 0.20). The authors concluded that compared with conventional therapy, NPWT significantly increased the rate of graft take and reduced the rate of re-operation when used to cover the wound bed with STSG. No significant impact on wound infection was found in this study. Moreover, these researchers stated that further studies of NPWT versus conventional therapy in a prospective, randomized design are needed to provide better quality outcome measures.
The authors stated that this meta-analysis had 2 main drawbacks. First, systematic reviews of the literature and meta-analyses provided the strongest scientific evidence when they pooled data from high-quality RCTs. Unfortunately, this was not possible; thus, these investigators had to rely on data extracted from cohort studies. Second, the included studies contained patients with different causes of injury and skin defects in parts. The non-standard baseline and distribution of the wound bed which may have been a source of clinical heterogeneity.
Inatomi et al (2019) stated that NPWT is generally used as a bolster for STSG after the graft has been secured with sutures or skin staples. In this study, NPWT was applied to secure STSGs without any sutures or staples. Surgical outcomes of using NPWT without sutures was compared with a control group. Patients with STSGs were divided into 2 groups: a “no suture” group using only NPWT, and a control group using conventional fixings. In the no suture group, the grafts were covered with meshed wound dressing and ointment. The NPWT foam was placed over the STSG and negative pressure applied. In the control group, grafts were fixed in place using tie-over bolster, securing with fibrin glue, or NPWT after sutures. A total of 30 patients with 35 graft sites participated in the study. The mean rate of graft take in the no suture group was 95.1 %, compared with 93.3 % in the control group, with no significant difference between them. No graft shearing occurred in the no suture group. Although the difference did not reach statistical significance, mean surgical time in the no suture group (31.5 mins) tended to be shorter than that in the control group (55.7 mins). The authors concluded that by eliminating sutures, the operation time tended to be shorter, suturing was avoided; and suture removal was not required meaning that patients could avoid the pain associated with this procedure. In addition, the potential for staple retention and its associated complications was avoided, making this method potentially beneficial for both medical staff and patients.
In a retrospective, cohort study, Li et al (2020) compared the clinical effects of continuous NPWT and conventional pressure dressing at hard-to-fix sites after STSG. From September 2017 to August 2019, a total of 129 patients who met the inclusion criteria and had spilt-thickness skin grafting at hard-to-fix sites were admitted to the First Affiliated Hospital of Air Force Medical University and included in this trial. The patients were divided into NPWT group (67 patients, 41 males and 26 females, aged 32 ± 6 years) and conventional pressure dressing group (62 patients, 37 males and 25 females, aged 30 ± 5 years) according to whether the hard-to-fix sites were applied with NPWT after spilt-thickness skin grafting. After debridement and spilt-thickness skin grafting at hard-to-fix sites in patients of 2 groups, the wounds of patients in conventional pressure dressing group were applied with conventional pressure bandaging after being filled with dry gauze; for the wounds of patients in NPWT group, the semi-permeable membrane was pasted and sealed for continuous negative pressure suction after filled with dry gauze and placed the drainage foam or drainage tube, with the negative pressure ranging from -16.6 to -9.9 kPa. The bandage was opened during the 1st dressing change on the 5th day after surgery in NPWT group and on the 7th day after surgery in conventional pressure dressing group. The skin graft surviving area and proportion, the area and proportion of hematoma, the incidence of common complications of skin graft were observed and calculated. The times of post-operative dressing change as well as the hospital length of stay (LOS) were counted. Data were statistically analyzed with 2 independent sample t-test, Cochran & Cox approximate t test, Chi-square test, and Fisher's exact probability test. At the 1st dressing change, the skin graft surviving area of patients in NPWT group was (420 ± 94) cm(2), which was significantly larger than (322 ± 97) cm(2) in conventional pressure dressing group (t' = 12.33, p < 0.01); the skin graft surviving area proportion of patients in NPWT group was 97.0 ± 2.3 %, which was significantly higher than 74.4 ± 4.8 % in conventional pressure dressing group (t' = 50.11, p < 0.01). At the 1st dressing change, the skin hematoma area of patients in conventional pressure dressing group was 31.7 ± 10.1 cm(2), which was significantly larger than 3.2 ± 0.7 cm(2) in NPWT group (t' = 23.04, p < 0.01); the skin hematoma area proportion of patients in conventional pressure dressing group was 7.3 ± 2.3 %, which was significantly higher than 0.7 ± 0.3 % in NPWT group (t' = 76.21, p < 0.01). At the 1st dressing change, there was 1 case of skin movement and no case of skin graft edge tear in NPWT group with an incidence of 1.5 % (1/67). In the conventional pressure dressing group, there were 4 cases of skin movement and 2 cases of skin graft edge tear with an incidence of 9.7 % (6/62), p < 0.05. The incidence of complication of skin graft of patients in NPWT group was significantly lower than that in conventional pressure dressing group (p < 0.05). The times of post-operative dressing change of patients in NPWT group was significantly less than that in conventional pressure dressing group (t = 7.93, p < 0.01). The post-operative hospital LOS in NPWT group was significantly less than that in conventional pressure dressing group (t = 11.71, p < 0.01). The authors concluded that continuous NPWT could effectively promote wound healing, improve the survival rate of skin graft, reduce the incidence of complications after skin grafting, and shorten the hospital LOS in STSG at hard-to-fix sites.
Mo et al (2021) stated that graft fixation is essential for the successful survival of skin grafts. NPWT could be used for fixing a skin graft, ensuring adhesion of the graft with continuous and uniform pressure. However, the reported short- and long-term effectiveness of NPWT in STSGs is inconsistent, with few studies on the long-term effectiveness (scar quality). To clarify the appropriate methods of skin graft fixation, these researchers carried out a retrospective, single-center study on the short- and long-term effectiveness of skin grafting using different fixation methods. This study examined patients who underwent STSG from December 2010 to June 2019. They were divided into 2 groups based on the skin graft-fixing method: an NPWT group and a conventional mechanical fixation group. Medical data including age, sex, underlying diseases, wound etiology, recipient site, surgical methods, surgical outcomes, post-operative complications, and follow-up data (Vancouver Scar Scale score and Patient and Observer Scar Assessment Scale score) were analyzed. A total of 392 cases were ultimately included in the analysis. Among them, 218 cases were fixed with NPWT for skin grafting and 174 with conventional mechanical fixation. No significant differences in baseline data were noted between the 2 groups. The total graft survival rate in the NPWT group was higher than that in the conventional mechanical fixation group (86.7 % versus 74.1 %, p = 0.002). Moreover, the infection rate in the NPWT group was lower than that in the conventional mechanical fixation group (5.5 % versus 13.2 %, p = 0.008). In terms of scar quality, no significant difference was observed, except for in the hand. Overall, the scar surface regularity was better in the NPWT group than in the control group (p = 0.019 for Patient Scar Assessment Scale, p = 0.025 for Observer Scar Assessment Scale). The authors concluded that NPWT was an effective approach for fixing skin grafts. Compared with conventional mechanical fixation, NPWT could significantly improve the survival rate and reduce the infection rate of STSG. In the long-term, NPWT could also improve scar surface regularity in the hand, with an esthetic effect that was more satisfactory to clinicians and patients.
Mello (2022) noted that dermal regeneration matrices (DRMs) represent a significant advance in wound treatment; however, their use remains limited because of high associated costs. Used correctly, DRMs help improve aesthetic and functional results of skin-grafted areas. This case series reported the use of a DRM of 1-mm and 2-mm thickness in the management of acute complex wounds. This is a retrospective analysis of a cohort of patients treated between 2015 and 2018. Complex wounds were defined as those with extensive loss of skin and subcutaneous tissue, or as those in critical areas, that required sequential and specialized treatment. Management of acute wounds involved debridement of devitalized tissue, wound bed preparation, DRM implantation, and STSG; and NPWT was used in all cases preoperatively, after DRM implantation, and after STSG. Results of integration of DRM and skin grafts were subjectively evaluated. The Vancouver Scar Scale was used to examine results 12 months post-operatively. Traumatic injuries were the most common etiology, and the extension of the treated wounds varied between 4 cm × 5 cm to 42 cm × 28 cm, in the greatest dimensions. A 2-mm-thick matrix was used in 14 cases, with skin grafting after 7 to 9 days. I n 6 cases, a 1-mm-thick matrix was used, immediately followed by skin grafting; NPWT was used in all cases. Dermal regeneration matrices and skin graft integration rates of almost 100 % were achieved in all cases; and no complications occurred. The authors concluded that these results showed use of DRM and NPWT was a good reconstructive option in the management of acute complex wounds that required STSG. With proper patient selection, such treatment is an important tool in the armamentarium of reconstructive procedures.
Furthermore, an UpToDate review on “Skin autografting” (Leon-Villapalos and Dziewulski, 2023) states that “Negative pressure wound therapy minimizes shearing and subgraft fluid accumulation. For large areas, and specifically for those close to joints, we always use negative pressure wound therapy dressings in the immediate post-graft period. It is also our preference for most other areas, when available. The device is usually left in place for 5 to 10 days after graft placement”.
Closed Incision Negative Pressure Wound Therapy for Reduction of Surgical Site Infection or Wound Dehiscence After Spinal Fusion or Primary Total Joint Arthroplasty
Ailaney et al (2021) noted that persistent wound drainage after TJA increases the risk of SSIs. While closed incision NPWT (ciNPWT) reduces infections in traumatic wounds; evidence for its use after elective TJA is limited. In a systematic review and meta-analysis, these investigators examined the effect of ciNPWT on risk of SSI and wound complications following TJA. Medline, Embase, CINAHL, and Cochrane Library were searched for RCTs comparing ciNPWT versus standard dressings after total hip arthroplasty (THA) and total knee arthroplasty (TKA). Studies exclusively involving THA for femoral neck fractures were excluded. Risk of SSI and non-infectious wound complications (blisters, seroma, hematoma, persistent drainage, dehiscence, and wound edge necrosis) following TJA were analyzed. SSI risk was lower with ciNPWT compared to standard dressings (3.4 % versus 7 %; RR 0.48, p = 0.007), specifically in revision THA and TKA (4.1 % versus 10.5 %; RR 0.41, p = 0.03). ciNPWT increased the non-infectious complication risk after primary TKA (RR 4.71, p < 0.0001), especially causing wound blistering (RR 12.66, p < 0.0001). ciNPWT decreased hospital LOS by 0.73 days (p = 0.04) and re-operation rate (RR 0.28, p = 0.01). The authors concluded that ciNPWT reduced SSI risk compared to standard dressings after revision TJA, but not primary TJA. ciNPWT was associated with greater than 12-fold increased risk of wound blistering after primary TKA. These researchers stated that ciNPWT played a role in revision TJA management; however, they that additional RCTs with uniform wound assessment methods must be carried out to sufficiently power findings and draw conclusions on the use of ciNPWT after primary TJA.
In a systematic review and meta-analysis, Lambrechts et al (2022) examined if ciNPWT would reduce SSI or wound dehiscence after spinal fusion. Following PRISMA guidelines, a systematic review and meta-analysis were carried out to identify studies using ciNPWT after spinal fusion. Funnel plots and quality scores of the studies were performed to determine if they were at risk of bias. Forest plots were carried out to identify the treatment effect of ciNPWT after spinal fusion. A total of 8 studies comprising 1,061 patients who received ciNPWT or a standard post-operative dressing after spinal fusion were included. The rate of SSI (ciNPWT, 4.49 % [95 % CI: 2.48 to 8.00] versus control, 11.32 % [95 % CI: 7.51 to 16.70]; p = 0.0103) was significantly lower for patients treated with ciNPWT. A fixed-effects model showed no significant difference between patients who received ciNPWT or a standard post-operative dressing with respect to requiring re-operations for wound debridement (OR, 1.25; 95 % CI: 0.64 to 2.41). Furthermore, wound dehiscence was not significantly different between the 2 groups, although it was non-significantly lower in ciNPWT-treated patients (ciNPWT, 4.59 % [95 % CI: 2.49 to 8.31] versus control: 7.48 % [95 % CI: 4.38 to 12.47]; p = 0.23). The authors concluded that ciNPWT may reduce the rates of SSI after spinal fusion. The use of ciNPWT may also significantly reduce the burden associated with post-operative wound complications; however, the meta-analysis was insufficiently powered to make this association. These researchers stated that additional studies may identify a subset of patients who may benefit from ciNPWT for other wound-related complications.
Negative Pressure Wound Therapy in Head and Neck Free Flap Reconstruction
Marouf et al (2022) provided the 1st systematic review of the immediate application of NPWT to the head and neck in free flap reconstruction. These investigators carried out a systematic search of the PubMed and Cochrane databases in October 2021 using the MeSH terms “negative pressure wound therapy”, “free flaps”, “microsurgery”, and “vacuum-assisted closure”. They included studies that examined the use of immediate NPWT in head and neck free flap reconstruction. Outcomes, indications, monitoring, and reported complications were retrieved. Of the 908 articles searched, 9 published between 2000 and 2021 were included: 4 retrospective studies and 5 case-series studies. NPWT was applied to 56 free flaps, and 54 had successful outcomes. The most common reported indication for flap reconstruction was malignancy. The authors concluded that NPWT has the potential to be a valuable tool for complicated wounds, and further studies are needed to quantify functional and aesthetic outcomes.
Prophylactic Negative Pressure Wound Therapy on Surgical Site Infections in Pancreatic Resection
In a systematic review and meta-analysis, Lenet et al (2022) examined the effect of prophylactic NPWT on SSI in patients undergoing pancreatectomy. These investigators searched electronic databases from inception until April 2022; RCTs comparing prophylactic NPWT to standard dressings in patients undergoing pancreatectomy were included. The primary outcome was the risk of SSI. Secondary outcomes included the risk of superficial and deep SSI and organ space infection (OSI). Random effects models were used for meta-analysis. A total of 4 single-center RCTs including 309 patients were identified; 3 studies were industry-sponsored, and 2 were at high-risk of bias. There was no significant difference in the risk of SSI in patients receiving NPWT versus control (14 % versus 21 %, RR = 0.72, 95 % CI: 0.32 to 1.60, p = 0.42, I2 = 53 %). Similarly, there was no significant difference in the risk of superficial and deep SSI or OSI. No significant difference was found on subgroup analysis of patients at high-risk of wound infection or on sensitivity analysis of studies at low-risk of bias. The authors concluded that prophylactic NPWT did not significantly lower the risk of SSI among patients undergoing pancreatectomy. These researchers stated that insufficient evidence exists to justify the routine use of NPWT.
VeraFlo (Intermittent Instillation Wound Vacuum)
In a porcine model, Leung et al (2010) examined the effects of normal saline instillation in conjunction with NPWT on wound healing. The effects of intermittent instillation of normal saline in conjunction with NPWT were examined to determine if instillation therapy would provide additional benefits in wound healing. Conventional NPWT using reticulated open cell foam (NPWT/ROCF) as delivered by V.A.C. Therapy was compared to V.A.C. Instill Therapy with normal saline in the treatment of porcine full-thickness excisional wounds. Wounds were treated with NPWT/ROCF or NPWT/ROCF with instillation therapy at approximately 4 cycles of normal saline instillation per day and dwell times of either 5 or 60 mins for the instilled saline on the wound bed. Instillation therapy with normal saline at either dwell time elicited a faster rate of wound filling with granulation tissue that contained an increase in total collagen content compared to continuous NPWT/ROCF alone. Analyses of wound contraction and the hydration state of the treated tissue exhibited no apparent differences between the experimental instillation therapy groups and the control NPWT/ROCF group. The authors concluded that the findings of this study suggested that instillation therapy with normal saline may result in wound fill with higher quality granulation tissue composed of increased collagen following wounding of cutaneous tissue compared to the use of NPWT/ROCF alone.
In a retrospective, cohort-control study, Kim et al (2014) examined the impact of NPWT with and without instillation. A total of 142 patients (NPWT, n = 74; therapy with instillation, 6-min dwell time, n = 34; and therapy with instillation, 20-min dwell time, n = 34) were included in the analysis. Number of operative visits was significantly lower for the 6-min and 20-min dwell time groups (2.4 ± 0.9 and 2.6 ± 0.9, respectively) compared with the no-instillation group (3.0 ± 0.9) (p ≤ 0.05). Hospital stay was significantly shorter for the 20-min dwell time group (11.4 ± 5.1 days) compared with the no-instillation group (14.92 ± 9.23 days) (p ≤ 0.05). Time to final surgical procedure was significantly shorter for the 6-min and 20-min dwell time groups (7.8 ± 5.2 and 7.5 ± 3.1 days, respectively) compared with the no-instillation group (9.23 ± 5.2 days) (p ≤ 0.05). Percentage of wounds closed before discharge and culture improvement for Gram-positive bacteria was significantly higher for the 6-min dwell time group (94 % and 90 %, respectively) compared with the no-instillation group (62 % and 63 %t, respectively) (p ≤ 0.05). The authors concluded that these findings suggested that NPWT with instillation (6-min or 20-min dwell time) was more beneficial than standard NPWT for the adjunctive treatment of acutely and chronically infected wounds that require hospital admission. These researchers noted that the choice of instillation solution may also play a significant role. They used Prontosan as their choice of instillation solution because of the combined benefit of 0.1% polyhexanide (anti-microbial) and 0.1 % betaine (surfactant). Prontosan has a high tolerability profile with in-vivo and in-vitro benefits at low concentrations and effectiveness against a wide variety of pathogens; however, many other solutions and combinations of solutions have been reported in the literature, including Dakin’s solution, silver nitrate, and mixed antibiotic solution. Others have suggested that normal saline be used as the instillation solution. The authors stated that perhaps the choice of instillation solution is not as critical as the fact that a solution is being bathed over the wound. Level of Evidence = III.
Kim et al (2015) state that NPWT with instillation is an adjunctive treatment that uses periodic instillation of a solution and negative pressure for a wide diversity of wounds. A variety of solutions have been reported, with topical antiseptics as the most frequently chosen option. In a prospective, randomized study, these researchers compared the outcomes of normal saline versus an antiseptic solution for NPWT with instillation for the adjunctive treatment of infected wounds. This trial compared 0.9 % normal saline versus 0.1 % polyhexanide plus 0.1 % betaine for the adjunctive treatment of infected wounds that required hospital admission and operative debridement. A total of 123 patients were eligible, with 100 patients randomized for the ITT analysis and 83 patients for the per-protocol analysis. The surrogate outcomes measured were number of operative visits, hospital LOS, time to final surgical procedure, proportion of closed or covered wounds, and proportion of wounds that remained closed or covered at the 30-day follow-up. There were no statistically significant differences in the demographic profiles in the 2 cohorts except for a larger proportion of male patients (p = 0.004). There was no statistically significant difference in the surrogate outcomes with the exception of the time to final surgical procedure favoring normal saline (p = 0.038). The authors concluded that the findings of this study suggested that 0.9 % normal saline may be as effective as an antiseptic (0.1 % polyhexanide plus 0.1 % betaine) for NPWT with instillation for the adjunctive inpatient management of infected wounds. Moreover, because of the limitations of this trial, definitive conclusions could not be drawn.
The authors stated that this study had several limitations. First, there was an ingrained institutional bias for aggressive serial excisional debridement; thus, the reliance on an antiseptic solution between operating room visits may be less important in the authors’ institution. Second, there was no control group used in this study; therefore, these investigators could not determine if he results reflected the experimental intervention of NPWT with instillation. In other words, they could not definitively determine if these subjects would have had similar outcomes without the use of NPWT with instillation. Third, investigator bias may have also skewed the results. From the authors’ previous published study (Kim et al, 2014), they observed that 0.1% polyhexanide plus 0.1 % betaine resulted in good outcomes. Therefore, potential candidates for this study may have been excluded because of the chance that the patient may have been randomized to the normal saline group. Every attempt was made to include all patients that met the very broad eligibility criteria, but the worst wounds or sickest patients may have been excluded from this study. However, this would have affected the cohorts equally. Thus, the principal focus of this study to compare solutions was uncontaminated. Fourth, this was not a blinded study; therefore, investigator bias may have also influenced the decision by the surgeon that the wound was sufficiently prepared for closure or coverage. Again, this bias would have favored 0.1 % polyhexanide plus 0.1 % betaine based on prior experience. However, the 30-day follow-up data showed no difference in proportion of closed wounds. This implied that these researchers did not favor one solution or another because, if they did bias for faster closure, they would most likely have observed a lower proportion of closed or covered wounds at the 30-day follow-up for the 0.1 % polyhexanide plus 0.1 % betaine cohort. In addition, the number of operating room visits was not different between the 2 cohorts indicating that closure/coverage decisions were similar in both groups.
Another limitation of this study was its overall study design. This study was best defined as an effectiveness study rather than an efficacy study. Although carried out in a prospective, randomized fashion, the broad eligibility criteria encompassing all wound causes, wound sizes, and anatomical locations preclude this trial from being identified as a typical comparative efficacy study. Therefore, the reader should acknowledge this lack of homogeneity of the study population and lack of adherence to the rules that govern a classic efficacy study design. However, the authors believed these results were meaningful because they reflected a real-world use of this type of therapy.
Malviya et al (2022) stated diabetic foot ulcer (DFU) is a common complication of uncontrolled diabetes; and NPWT with irrigation of normal saline is one of the methods for wound care and dressing techniques in DFU. Wound assessment is another aspect of DFU management for deciding whether the wound is prepared or not for coverage. These investigators employed DEPA score (D: depth of the ulcer; E: extent of bacterial colonization; P: phase of ulcer; and A: associated etiology) as a wound assessment tool in DFU. They reported on a case series that included 11 patients with DFU who were treated using NPWT with simultaneous irrigation of normal saline. All 11 patients were men aged more than 60 years. Most patients had duration of diabetes for less than 10 years. Staphylococcus aureus (n = 5, 45.4 %) was most common bacterial flora. Most patients in series presented with DEPA score more than 7; and after the use of NPWT instillation therapy significant improvement was observed with score in most of the patient with DEPA score below 6. Mean time for NPWT (irrigation) application was 15 days. Mean time of wound preparation was 18.7 days. Final surgical procedures executed in all patients included split skin grafting performed in 7 patients. A total of 4 patients had wound coverage by reverse sural flap (n = 2), medial plantar flap (n = 1) and local flap coverage (n = 1). The authors concluded that NPWT with normal saline irrigation was an effective method of wound preparation in DFU. DEPA score is an important tool for assessment of wound preparation that rendered exact information for timing of wound coverage once diabetic foot wound was prepared. These researchers stated that the drawbacks of this trial were the small sample size (n = 11) and the lack of a control group, which did not allow direct comparison of NPWT with irrigation feature with conventional NPWT. Moreover, they stated that further investigation with a large series is needed to prove the effectiveness of instillation therapy of NPWT dressing over the NPWT.
An UpToDate review on “Negative pressure wound therapy” (Gestring, 2023) does not include discussion on NPWT instillation (NPWTi) with saline.
Furthermore, an UpToDate review on “Overview of treatment of chronic wounds” (Evans and Kim, 2023) states that “Negative pressure wound therapy (NPWT), also called vacuum-assisted wound closure, refers to wound dressing systems that continuously or intermittently apply subatmospheric pressure to the surface of a wound … Innovations include NPWT with instillation (NPWTi). This therapy combines the benefits of traditional NPWT and irrigation. In the acute care setting, NPWTi can expedite wound bed preparation”. However, NPWT with instillation (NPWTi) is not mentioned in the “Summary and Recommendations” section of this UTD review.
Appendix
Specifications of Equipment and Supplies
NPWT is provided with an integrated system of components. This system contains a pump, dressing sets and a separate collection canister. Wound suction systems that do not contain all of the required components are not classified as NPWT. See below for component specifications.
For purposes of this policy, a NPWT pump describes a stationary or portable Negative Pressure Wound Therapy (NPWT) electrical pump which provides controlled subatmospheric pressure that is designed for use with NPWT dressings and canisters to promote wound healing. The NPWT pump must be capable of being selectively switched between continuous and intermittent modes of operation and is controllable to adjust the degree of subatmospheric pressure conveyed to the wound in a range of 40-80 mm Hg subatmospheric pressure. The system must contain sensors and alarms to monitor pressure variations and exudate volume in the collection canister.
A NPWT dressing kit describes an allowance for a dressing set which is used in conjunction with a stationary or portable NPWT pump. A single dressing kit is used for each single, complete dressing change, and contains all necessary components, including but not limited to any separate, non-adherent porous dressing(s), drainage tubing, and an occlusive dressing(s) which creates a seal around the wound site for maintaining subatmospheric pressure at the wound.
A NPWT collection cannister describes a canister set which is used in conjunction with a stationary or portable NPWT pump and contains all necessary components, including but not limited to a container to collect wound exudate. Canisters may be various sizes to accommodate stationary or portable NPWT pumps.
Contraindications for Negative Pressure Wound Therapy (NPWT)
NPWT is contraindicated in the presence of any the following:
- Cancer present in the wound; or
- Inadequately debrided wounds; granulation tissue that will not form over necrotic tissue; or
- Presence of untreated coagulopathy; or
- The presence in the wound of necrotic tissue with eschar, if debridement is not attempted; or
- The presence of a fistula to an organ or body cavity within the vicinity of the wound; or
- Untreated osteomyelitis or spesis within the vicinity of the wound.
List of Negative Pressure Wound Therapy (NPWT) DevicesFootnotes*
- ActiV.A.C.® Therapy Unit
- Engenex® Advanced NPWT System
- Exusdex® wound drainage pump
- EZCARE Negative Pressure Wound Therapy
- Genadyne A4 Wound Vacuum System
- InfoV.A.C.® Therapy Unit
- Invia Liberty Wound Therapy
- Invia Vario 18 ci Wound Therapy
- Medela® Invia Liberty pump
- Mini V.A.C.®
- NPD 1000 Negative Pressure Wound Therapy System
- Prodigy™ NPWT System (PMS-800 and PMS-800V)
- PRO-II™
- PRO-I™
- RENASYS™ EZ Negative Pressure Wound Therapy
- SVEDMAN™ and SVED™ Wound Treatment Systems
- V.A.C.® ATS™
- V.A.C.® Freedom™
- V.A.C.® Instill Device
- V.A.C.® Therapy Unit
- V.A.C.® (Vacuum Assisted Closure™)
- V1STA Negative Pressure Wound Therapy
- Venturi™ Negative Pressure Wound Therapy
Footnotes*These devices have U.S. Food and Drug Administration 510(k) clearance for marketing in the United States. This list is not all-inclusive.
Documentation Requirements
Information describing the history, previous treatment regimens (if applicable), and current wound management for which an NPWT pump is being billed must be present in the member’s medical record and be available for review upon request. This documentation must include such elements as length of sessions of use, dressing types and frequency of change, and changes in wound conditions, including precise measurements, quantity of exudates, presence of granulation and necrotic tissue and concurrent measures being addressed relevant to wound therapy (debridement, nutritional concerns, support surfaces in use, positioning, incontinence control, etc.).
Information describing the wound evaluation and treatment, recorded in the member’s medical record, must indicate regular evaluation and treatment of the beneficiary’s wounds, as detailed in the Policy Section. Documentation of quantitative measurements of wound characteristics including wound length and width (surface area), and depth, and amount of wound exudate (drainage), indicating progress of healing must be entered at least monthly. The supplier of the NPWT equipment and supplies must obtain from the treating clinician, an assessment of wound healing progress, based upon the wound measurement as documented in the member’s medical record, in order to determine whether the equipment and supplies continue to be medically necessary. (The supplier need not view the medical records in order to bill for continued use of NPWT. Whether the supplier ascertains that wound healing is occurring from month to month via verbal or written communication is left to the discretion of the supplier. However, the member’s medical records may be requested in order to corroborate that wound healing is/was occurring as represented on the supplier’s claims for reimbursement.)
When billing for NPWT, an ICD-9-CM diagnosis code (specific to the 5th digit or narrative diagnosis), describing the wound being treated by NPWT, must be included on each claim for the equipment and related supplies.
The medical record must include a statement from the treating physician describing the initial condition of the wound (including measurements) and the efforts to address all aspects of wound care listed in the Policy Section. For each subsequent month, the medical record must include updated wound measurements and what changes are being applied to effect wound healing. Month-to-month comparisons of wound size must compare like measurements i.e. depth compared to depth or surface area compared to surface area.
If the initiation of NPWT occurs during an inpatient stay, in order to accurately account for the duration of treatment, the initial inpatient date of service must be documented. This date must be available upon request.
When NPWT therapy exceeds 4 months on the most recent wound, individual consideration for one additional month at a time may be sought using the appeals process. Information from the treating physician’s medical record, contemporaneous with each requested one-month treatment time period extension, must be submitted with each appeal explaining the special circumstances necessitating the extended month of therapy. Note, this policy provides coverage for the use of NPWT limited to initiating healing of the problem wounds described in the Policy Section section of this CPB rather than continuation of therapy to complete healing since there is no published medical literature demonstrating evidence of a clinical benefit for the use of NPWT to complete wound healing. Therefore, general, vague or nonspecific statements in the medical record such as “doing well, want to continue until healed” provide insufficient information to justify the need for extension of treatment. The medical record must provide specific and detailed information to explain the continuing problems with the wound, what additional measures are being undertaken to address those problems and promote healing and why a switch to alternative treatments alone is not possible.
When billing for quantities of canisters greater than those described in the Policy Section as the usual maximum amounts, there must be clear and explicit information in the medical record that justifies the additional quantities.
References
The above policy is based on the following references:
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