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Background
Standard electro-surgical tools and lasers remove tissue by thermal energy. Other methods of tissue decomposition have evolved to try to address the problems associated with high heat and damage to the surrounding tissue.
Coblation is a new surgical method for removing soft tissue during arthroscopic surgery developed by ArthroCare Corporation (Sunnyvale, CA). Coblation is a method of non-thermal volumetric tissue removal through molecular dissociation, similar to that of excimer lasers. Coblation uses the electrically conductive fluid employed in arthroscopic surgeries in the gap between the electrode and tissue. When electrical current is applied to this fluid, it turns into a charged layer of particles, called a plasma layer. Charged particles accelerate through the plasma and gain sufficient energy to break the molecular bonds within cells. This causes the cells to disintegrate molecule by molecule, so that tissue is volumetrically removed.
Coblation-assisted surgery uses a continuous mode of operation rather than the pulsed mode required for lasers. The purpose of a continuous mode of operation is to allow for coagulation of smaller blood vessels, and when used in sub-ablation mode, the intent is to produce hemostasis in larger vessels as well as shrinkage of collagen. Coblation uses a relatively low-temperature plasma, compared with lasers of high-power density beam of photons with their subsequent heat production. Because Coblation uses a low-temperature, the intent is to decrease the risk for thermal damage to surrounding tissues. ArthroCare believes Coblation will provide a more precise operative result, reduce surgical time, speed recovery and reduce post-operative pain. However, these claims are not supported by well controlled randomized studies.
Coblation devices such as the Topaz Microdebrider (ArthroCare, Sunnyvale, CA) are also being studied for their use in treating musculoskeletal conditions. In a prospective, non-randomized consecutive case series, Tasto and colleagues (2005) assessed the safety and effectiveness of microtenotomy using a radiofrequency (RF) probe to treat chronic tendinosis of the common extensor tendon origins of the elbow (lateral epicondyle). The average age of the 13 patients was 48.3 +/- 5.5 years. Before receiving the microtenotomy, all patients had tendinosis symptoms for 6 months or longer and had failed conservative treatment. The RF-based microdebridement was performed on the symptomatic tendon using the Topaz Microdebrider device. Patients were followed-up at regular post-operative intervals for 24 months. Pain status was documented using a visual analog scale self-reported measure. Functional outcome was assessed using the upper limb DASH evaluation and grip-strength measures. Quality of life assessment was evaluated using the SF-36 questionnaire. Magnetic resonance imaging was performed at regular intervals over the follow-up period. Patients reported significantly reduced pain from baseline at the 7- to 10-day post-operative examination (p < or = 0.01). Pain reduction was statistically stable from 7 to 10 days through the 24-month post-operative period (p < or = 0.01). Limb-specific functional outcomes and quality of life scores were improved over baseline values. There were no peri-operative or post-operative complications related to the procedure. The authors concluded that the RF-based microtenotomy procedure was safe and effective through at least 2 years. This procedure provides a valuable addition for treating patients with lateral epicondylitis associated with tendinosis who have failed conservative therapy. This was a small, short-term, non-randomized study; its findings need to be validated by future prospective randomized studies with large sample sizes and longer follow-up. In addition, evidence is needed regarding the effectiveness of this approach compared to established methods of management of these musculoskeletal conditions.
There is insufficient evidence in the medical literature to support the use of Coblation non-thermal volumetric tissue reduction for removing soft tissue during arthroscopic surgery or for treating musculoskeletal conditions.
On the other hand, there is evidence to support the use of Coblation tonsillectomy. In a double-blind, randomized controlled study, Arya et al (2003) compared post-operative pain following Coblation tonsillotomy versus Coblation tonsillectomy. No statistically significant difference in pain was demonstrated in the group of 14 patients studied. Nevertheless, the authors recommended tonsillectomy over tonsillotomy. Furthermore, in a study to measure the benefits of Coblation tonsillectomy (n = 844) against traditional tonsillectomy (n = 743), Belloso et al (2003) concluded that Coblation tonsillectomy was associated with a lesser incidence of delayed hemorrhage, more significantly in the pediatric population. The new technique using tissue Coblation for tonsil dissection offers significant advantages in the post-operative period compared with dissection tonsillectomy with bipolar diathermy hemostasis. Coblation is associated with less post-operative pain and early return to daily activities. Also, there are fewer secondary infections of the tonsil bed and significantly lower rates of secondary hemorrhage with Coblation.
In a prospective, controlled single-blind study, Stoker et al (2004) compared post-operative recovery after tonsillectomy using Coblation excision (CES, n = 44) or conventional electro-surgery (ES, n = 45). The authors concluded that children who received CES tonsillectomy appeared to experience a better quality post-operative course, with no detriment to operative benefits of conventional ES.
A review by the National Institute for Clinical Excellence (NICE, 2003) recommended Coblation tonsillectomy for the following indications: (i) recurrent or chronic tonsillar infection, (ii) tonsillar hypertrophy leading to respiratory symptoms or airway obstruction, (iii) peri-tonsillar abscess, and (iv) recurrent middle ear infection where tonsillar hypertrophy is believed to be an exacerbating factor. Subsequent guidance from NICE (2005) concluded that "[c]urrent evidence on the safety and efficacy of electrosurgery (diathermy and coblation) for tonsillectomy appears adequate to support the use of these techniques, provided that normal arrangements are in place for consent, audity, and clinical governance."
A Cochrane evidence review (Burton and Doree, 2007) concluded that, "In terms of postoperative pain and speed and safety of recovery, there is inadequate evidence to determine whether coblation tonsillectomy is better or worse than other methods of tonsillectomy. Evidence from a large prospective audit suggests that it has been associated with a higher level of morbidity, in terms of postoperative bleeding. Large, well-designed randomised controlled trials supplemented by data from large prospective audits are needed to produce information on effectiveness and morbidity respectively."
Freeman and Mehdian (2008) evaluated the evidence for 3 minimally invasive methods in the treatment of discogenic low back pain (LBP) and radicular pain: (i) intra-discal electrothermal therapy (IDET), (ii) percutaneous discectomy, and (iii) Coblation nucleoplasty. An electronic search of the literature carried out using the Cochrane Library database (2007) and Medline (1966 to 2007) identified 77 references relating to IDET, 363 to percutaneous discectomy, and 36 to nucleoplasty. Two randomized controlled trials (RCTs) assessed the effectiveness of IDET; 1 demonstrated a positive effect on pain severity only, whereas the other demonstrated no substantial benefit. Other RCTs showed that percutaneous intra-discal RF thermocoagulation is ineffective for the treatment of discogenic LBP. Trials of automated percutaneous discectomy suggested that clinical outcomes after treatment are at best fair and often worse when compared with microdiscectomy. There are no published RCTs assessing Coblation (ArthroCare Spine, Stockholm, Sweden) technology.
In an American Pain Society's clinical practice guideline on non-surgical interventional therapies for LBP, Chou et al (2009) noted that although use of certain interventional therapies is common or increasing, there is also uncertainty or controversy about their efficacy. These investigators performed electronic database searches on Ovid Medline and the Cochrane databases through July 2008 to identify RCTs and systematic reviews of local injections, botulinum toxin injection, prolotherapy, epidural steroid injection, facet joint injection, therapeutic medial branch block, sacroiliac joint injection, intra-discal steroid injection, chemonucleolysis, RF denervation, IDET, percutaneous intra-discal RF thermocoagulation, Coblation nucleoplasty, and spinal cord stimulation. All relevant studies were methodologically assessed by 2 independent reviewers using criteria developed by the Cochrane Back Review Group (for trials) and by Oxman (for systematic reviews). A qualitative synthesis of results was performed using methods adapted from the U.S. Preventive Services Task Force. For sciatica or prolapsed lumbar disc with radiculopathy, these researchers found good evidence that chemonucleolysis is moderately superior to placebo injection but inferior to surgery, and fair evidence that epidural steroid injection is moderately effective for short-term (but not long-term) symptom relief. They found fair evidence that spinal cord stimulation is moderately effective for failed back surgery syndrome with persistent radiculopathy, though device-related complications are common. They also found good or fair evidence that prolotherapy, facet joint injection, intra-discal steroid injection, and percutaneous intra-discal RF thermocoagulation are not effective. Insufficient evidence exists to reliably evaluate other interventional therapies. The authors concluded that few non-surgical interventional therapies for LBP have been shown to be effective in RCTs.
Sean et al (2010) stated that microtenotomy coblation using a RF probe is a minimally invasive procedure for treating chronic tendinopathy. It has been described for conditions including tennis elbow and rotator cuff tendinitis. There have been no studies to show the effectiveness of such a procedure for plantar fasciitis. In this case-serieis study, a total of 14 patients with plantar fasciitis who had failed conservative treatment underwent TOPAZ RF treatment for their symptoms. The RF-based microdebridement was performed using the TOPAZ Microdebrider device (ArthroCare, Sunnyvale, CA). There were 6 men and 8 women with an average age of 44.0 years (23 to 57). There were 15 feet, with 6 right and 9 left feet. Subjects were followed-up for up to 6 months thereafter. Pre-operative, 3 and 6 months post-operative AOFAS ankle-hindfoot and SF-36 scores were analysed. There was a significant improvement in mean pre-operative, post-operative 3- and 6-month AOFAS hindfoot scores from 34.47 to 69.27 and 71.33 (p = 0.00), respectively. There was a significant decrease in SF-36 for bodily pain, and significant increases in physical and social function scores. Overall, 12 out of 14 (85.7 %) patients reported good to excellent satisfaction results at 6 months, and 12 out of 14 (85.7 %) patients have had their expectations met from the procedure at 6 months follow-up. The authors concluded that TOPAZ RF coblation is a good and effective method for the treatment of recalcitrant plantar fasciitis. T hey stated that these early results are encouraging, and they will continue to evaluate the patients over a longer follow-up period.
In a retrospective case-series study, Carney et al (2010) examined the effectiveness of RF cold ablation (coblation) for the treatment of laryngo-tracheal recurrent respiratory papillomatosis, by comparing treatment intervals for coblation and CO2 laser vaporization. A total of 6 adult patients with advanced laryngo-tracheal recurrent respiratory papillomatosis were treated for at least 2 years by CO2 laser vaporization with or without intra-lesional cidofovir. All 6 subsequently underwent treatment with RF coblation with or without intra-lesional cidofovir. Coblation resulted in longer periods between interventions, compared with CO2 laser (p = 0.03). The authors concluded that RF coblation appears to be an attractive alternative technique to CO2 laser for the surgical treatment of advanced laryngo-tracheal papillomata. The findings of this small study need to be validated by well-designed studies.
Dasenbrock and colleagues (2012) stated that plasma mediated RF ablation (pmRFA) may allow for the percutaneous treatment of spinal tumors with a decreased risk of thermal injury to neural structures compared with traditional (RF or interstitial laser) ablation. However, usage of pmRFA has not been previously reported for a primary bone tumor, including an osteoid osteoma. In this small study, 3 patients with a spinal osteoid osteoma underwent pmRFA. The procedure was performed under computed tomography guidance using the 11-gauge Coblation SpineWand (ArthroCare). One lesion (at T11) was directly abutting the spinal canal. With an average follow-up of 20.7 (range of 16 to 24) months, the mean visual analog scale score for back pain decreased from 8.67 to 0.67 and no patient experienced tumor recurrence. The authors concluded that pmRFA of spinal osteoid osteomas is feasible, even when the tumor is abutting the spinal canal. Moreover, they stated that larger studies with a longer follow-up are needed to further delineate the safety and effectiveness of this technique.
Trial et al (2012) noted that debridement is needed to prepare the wound bed, essentially in removing undesired tissues observed both in acute wound after burns or trauma and in chronic wounds (e.g., diabetic foot ulcers, leg ulcers, and pressure ulcers). Surgical debridement has been described as one of the most effective methods but can be contraindicated in the elderly, arteriopathic context, or patients under effective anti-coagulation. Recently described debridement technologies are based on application of important mechanical severing forces over the wound surface using high-power hydrojets. High water flux acts as a vector for separating necrotic and sloughy tissues from the wound bed and aspirates them out of the wound immediately. Electrical powered techniques and lasers were also scarcely described. The Coblation debridement technology presented here was based on the local induction of a focused plasma field chemically deleting undesired tissues. This technique is a modification of conventional electro-surgical devices, developed in 1928 where tissue excision and coagulation of tissues were observed. Principles of plasma-mediated debridement were based on a bipolar radiofrequency energizing the molecules, thus creating a plasma field. This glow discharge plasma produces chemically active radical species from dissociation of water, breaking molecular bonds, and causing tissue dissolution. The thermal effects are a by-product, which can be modulated by modifying the electrode construction, limiting the local temperature to less than 50°C in order not to induce wound bed re-necrosis. The authors described the principle, the first technical adaptation for wound debridement, and the potential clinical interest of the Coblation technology. Well-designed studies are needed to develop clinical evidence of Coblation technology for surgical wound debridement.
Pierson et al (2012) presented 2 cases of advanced juvenile nasopharyngeal angiofibroma (JNA) to illustrate the advantages of endoscopic Coblation-assisted resection of intra-nasal extensions of these masses. Both patients (an 11-year old boy and a 14-year old boy) presented with a large, extensive mass (Radkowski stage IIIb and Fisch stage IVb in both cases). After embolization was performed on each patient, his JNA was partially ablated via an endoscopic approach with the Coblator II Surgery System with an EVac Xtra Plasma Wand in conjunction with an image-guided navigation system. Both patients experienced resolution of their nasal obstruction with removal of the intra-nasal extension of the tumor. Coblation allowed for a controlled debulking of the tumors with less blood loss and without the need for multiple instruments. To the best of their knowledge, the authors’ report was one of the first to describe image-guided endoscopic Coblation of advanced JNA tumors. They stated that future studies in adequately sized populations are needed to determine the safety and effectiveness of Coblation-assisted endoscopic removal of both advanced and lower-stage JNAs.
In a prospective, open-label, non-randomized trial, Di Rienzo Businco evaluated the effectiveness of adding Coblation-assisted inferior turbinoplasty to a medical treatment regimen for symptoms associated with hypertrophic inferior turbinates. Patients were assigned to treatment groups in order of enrolment into the study. From June 2007 to June 2008, a total 220 patients with allergic rhinitis (AR) and hypertrophic inferior turbinates were enrolled and assigned into 2 groups: (i) the surgical group who received radiofrequency thermal ablation inferior turbinoplasty and medical therapy, and (ii) the medical group who received medical therapy only. Groups were further divided into 2 allergen types based on antigen sensitivity: perennial and seasonal. Subjective complaints (nasal obstruction, itching, rhinorrhea, sneezing), clinical rhinoendoscopy and rhinomanometry tests results were recorded at the start of the study and 2 months post-treatment. Effect sizes for the mean improvements after treatment were tabulated for all groups. All study outcomes improved within all groups. Comparison between medical and surgical groups showed higher improvement in both perennial and seasonal, respectively, in nasal obstruction, sneezing, rhinomanometry, and rhinomanometry after nasal provocation test (NPT). Itching improved only in perennial allergen type. Rhinoendoscopy clinical score showed improvement in surgical group over medical group in both allergen types. The authors concluded that Coblation-assisted turbinate reduction is a promising adjunct to medical therapy in patients with persistent symptoms associated with AR. Patients undergoing this surgery had greater reduction of symptoms than patients receiving medical therapy alone, where patients with perennial allergies appeared to benefit most.
Li and colleagues (2013) examined the therapeutic effect of nasal Coblation plasma surgery for the treatment of persistent allergic rhinitis (PAR). A total of 100 patients with mite-sensitized moderate to severe PAR who underwent nasal Coblation plasma surgery (inferior turbinoplasty plus nasal agger ablation) were enrolled in this study. There were 68 males and 32 females patients aged 16 to 62 years (mean of 36.3 years). The visual analog scale (VAS) for global rhinitis symptoms, NPT, anterior rhinomanometry, and T&T olfactometry were used to assess the short-term outcomes, pre-operatively and post-operatively at the end of 3 months after surgical procedure. SPSS19.0 software was applied for statistical analysis. At 3months after treatment, the total nasal symptom VAS scores significantly decreased from 7.0 ± 2.0 to 2.5 ± 1.5 (X(-) ± s; t = 18.00, p = 0.0001). All patients were allergic to house dust mites with positive NPT before treatment. At 3 months from the Coblation intervention, 88.0 % of the patients changed from positive NPT to negative, while 12.0 % remained as positive. There was a significant reduction in total nasal resistance, which diminished from 0.772 ± 0.224 to 0.221 ± 0.112 kPa·s·L(-1) after treatment (t = 22.00, p = 0.0001). Pre-operative olfactory tests showed hyposmia in 31.0 % of the patients, with 22 cases for slight and 9 cases for moderate disorder. Three months after treatment, 13.0 % were diagnosed as hyposmic, with 7 cases for slight and 6 cases for moderate disorder (χ(2) = 10.44, p = 0.005). The authors concluded that nasal Coblation plasma surgery provided favorable short-term outcomes in terms of remarkable improvement in nasal symptoms, hyper-reactivity of nasal mucosa, nasal flow and olfactory function in patients with moderate to severe PAR, but long-term effect needed further observation.
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