Brachial Plexus Surgery

Number: 0850

Table Of Contents

Policy
Applicable CPT / HCPCS / ICD-10 Codes
Background
References

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Policy

Aetna considers neuroplasty (neurolysis or nerve decompression) medically necessary in the treatment of a brachial plexus neuromas and other brachial plexus lesions.

Aetna considers dorsal root entry zone (DREZ) coagulation medically necessary in the treatment of brachial plexus avulsion.

Aetna considers soft tissue reconstruction surgeries (e.g., triangle tilt surgery and the Mod-Quad procedure) medically necessary in the treatment of obstetric brachial plexus injury (BPI) if functional recovery does not ensue in 3 or more months.  Note: There is a lack of reliable evidence that one type of reconstructive soft tissue technique is more effective than others for obstetric BPIs.

Aetna considers the following interventions experimental and investigational because their effectiveness has not been established:

• Bionic reconstruction for brachial plexus avulsion
• Computer-assisted dorsal root entry zone microcoagulation (CA-DREZ) for brachial plexus avulsion
• Therapeutic taping for scapular stabilization
• Vascularized brachial plexus allo-transplantation for traumatic BPI.

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Table:

CPT Codes / HCPCS Codes / ICD-9 Codes

Code	Code Description
Information in the [brackets] below has been added for clarification purposes.   Codes requiring a 7th character are represented by "+":
CPT codes covered if selection criteria are met:
Triangle Tilt Surgery, Mod-Quad Procedure - no specific code:
Neurolysis:
CPT codes covered if selection criteria are met:
64713	Neuroplasty, major peripheral nerve, arm or leg, open; brachial plexus
ICD-10 codes covered if selection criteria are met:
D21.0	Benign neoplasm of connective and other soft tissue of head, face and neck
D21.10 - D21.12	Benign neoplasm of connective and other soft tissue of upper limb, including shoulder
G54.0	Brachial plexus disorders
P14.3	Other brachial plexus birth injury
S14.3xx+	Injury of brachial plexus
Vascularized brachial plexus allo-transplantation:
CPT codes not covered for indications listed in the CPB :
64912	Nerve repair; with nerve allograft, each nerve, first strand (cable)
64913	Nerve repair; with nerve allograft, each additional strand (List separately in addition to code for primary procedure)
ICD-10 codes not covered for indications listed in the CPB (not all-inclusive):
G54.0	Brachial plexus disorders
Dorsal root entry zone (DREZ) coagulation :
CPT codes covered if selection criteria are met: :
63170	Laminectomy with myelotomy (eg, Bischof or DREZ type), cervical, thoracic, or thoracolumbar
64640	Destruction by neurolytic agent; other peripheral nerve or branch
ICD-10 codes covered if selection criteria are met:
S14.3xx+	Injury of brachial plexus [brachial plexus avulsion]
Computer-assisted dorsal root entry zone (CA-DREZ) coagulation:
CPT codes not covered for indications listed in the CPB :
+20985	Computer-assisted surgical navigational procedure for musculoskeletal procedures, image-less (List separately in addition to code for primary procedure)
Bionic reconstruction:
CPT codes not covered for indications listed in the CPB:
No specific code
ICD-10 codes not covered for indications listed in the CPB (not all-inclusive):
S14.3xx+	Injury of brachial plexus [brachial plexus avulsion]
Therapeutic taping for scapular stabilization:
CPT codes not covered for indications listed in the CPB :
29240	Strapping; shoulder (eg., Velpeau) [therapeutic taping]
ICD-10 codes not covered for indications listed in the CPB (not all-inclusive):
G54.0	Brachial plexus disorders
M21.821 - M21.829	Other specified acquired deformities of upper arm [winged scapula]
P14.3	Other brachial plexus birth injury

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Background

The brachial plexus is a network of nerves located in the neck and axilla, composed of the anterior branches of the lower 4 cervical and first 2 thoracic spinal nerves that supply the chest, shoulder, and arm.  Injuries to the brachial plexus affect the nerves supplying the shoulder, upper arm, forearm and hand, causing numbness, tingling, pain, weakness, limited movement, or even paralysis of the upper limb.  Brachial plexus lesions are classified as either traumatic or obstetric.  Brachial plexopathy is the pathologic dysfunction of the brachial plexus.  When the brachial plexus is injured during delivery, the nerves become damaged and result in loss of muscle control and paralysis.  This condition is also known as Erb’s palsy.

Brachial plexus avulsion is the tearing away or forcible separation of nerves of the brachial plexus (a network of nerves that conducts signals from the spine to the shoulder, arm and hand) from the spine, the point of origin.  Symptoms of brachial plexus injuries may include a limp or paralyzed arm, lack of muscle control in the arm, hand, or wrist, and lack of feeling or sensation in the arm or hand.  Brachial plexus injuries may occur during birth: the baby's shoulders may become impacted during the birth process causing the brachial plexus nerves to stretch or tear. 

Brachial neuroplasty (neurolysis or nerve decompression) is the surgical repair or restoration of nerve tissue.  The release of adhesions around a nerve (freeing of intact nerve from scar tissue) is performed to relieve pain and disability.  It is written in the 2008 textbook "Frontera: Essentials of Physical Medicine and Rehabilitation", that surgery is an option in cases of traumatic plexopathy but has variable results.  Surgical techniques such as nerve grafting, free muscle transfer, neurolysis, and neurotization are used.  Surgeons who use these techniques frequently differ considerably in their approach to them, making conclusions about their efficacy difficult.  According to the textbook "Bradley: Neurology", the surgical treatment of traumatic plexopathy depends on the extent of the lesion.  Depending on the findings, neurolysis, nerve grafting or re-neurotization is performed.  In the textbook "Browner; Skeletal Trauma", it is written in reference to nerve injuries of the brachial plexus, when a neuroma in continuity is found it may be resected and repaired or neurolysis may be performed.

Dorsal root entry zone (DREZ) coagulation (also known as dorsal root entry zone lesion) is a surgical procedure in which ablative lesions are made at the dorsal root entry zones of the spinal cord.  These lesions are made with a radiofrequency lesion generator or laser through an open exposure of the cord via laminectomy.  Pain-producing nerve cells are destroyed with radiofrequency heat lesions.

Computer-assisted dorsal root entry zone microcoagulation (CA-DREZ) is a surgical procedure in which ablative lesions are made at the dorsal root entry zones of the spinal cord.  These lesions are made with a radiofrequency lesion generator or laser through an open exposure of the cord via laminectomy.  It involves electrical recording inside the spinal cord at the time of surgery to identify regions of abnormally active pain-producing nerve cells.  These abnormal cells are then destroyed with radiofrequency heat lesions.

The Triangle Tilt is a surgical procedure that addresses scapular elevation in children with obstetric brachial plexus injury (OBPI) through the bony realignment of the clavicle and scapula.  This realignment, or tilting, is of the triangle formed by clavicle and scapula.  As the scapula elevates, the plane of the triangle is steepened.  The purpose of the triangle tilt, therefore, is to normalize the plane of this triangle or, to reduce the elevation of the scapula and normalize the spatial relationship between the sides of the triangle.

Nath et al wrote in 2010 the triangle tilt surgery restores the distal acromioclavicular triangle from an abnormal superiorly angled position to a neutral position, thereby restoring normal glenohumeral anatomic relationships.  The findings of a study investigating the effects of triangle tilt surgery on glenohumeral joint anatomy in 100 OBPI patients were reported.  Axial computed tomography and magnetic resonance images taken before and 12- to 38-months after surgery showed significant improvements in both posterior subluxation and glenoid version.  Patients with complete posterior glenohumeral dislocation improved from 19 % pre-operatively to 11 % post-operatively.  Glenoid shape was also improved, with 81 % of patients classified as concave or flat after surgery compared with 53 % before surgery.  The authors concluded these anatomic improvements after triangle tilt surgery hold promise for improving shoulder function and quality of life for OBPI patients.

The Mod Quad procedure is considered a secondary surgery in children with brachial plexus injury used to correct muscle imbalances.  Among the muscles injured in Erb's are the abductors of the shoulder (that lift the arm over the head), as well as the external rotators (that help to turn the upper arm outward and to open the palm of the hand).  At the same time, the internal rotators (muscles that turn the arm and palm inward) and adductors (muscles that pull the arm to the side) of the arm are not involved in the injury because they are supplied by the lower roots of the plexus.  These strong muscles overpower the weak muscles and over time the child cannot lift the arm over the head or turn the palm out, because of the muscle imbalance.  In order to use the hand effectively, the elbow becomes bent, which eventually becomes fixed because of weakness of the triceps (the elbow straightening muscle).  The elbow-bent posture (also known as the Erb's Engram) contributes to the appearance of the arm being shorter. 

For this muscle imbalance, a group of muscle releases and transfers can put the arm in a more natural position and help to lift the arm over the head.  Known as the "quad" procedure, it has 4 components:

• Latissimus dorsi muscle transfer for external rotation and abduction
• Teres major muscle transfer for scapular stabilization
• Subscapularis muscle release
• Axillary nerve decompression and neurolysis).  Depending on the individual child, other nerve decompressions or muscle/ tendon transfers (such as pectoralis muscle releases) might be performed at the same time (the modified quad or "Mod Quad" procedure).

Louden et al (2013) conduct a meta-analysis and systematic review analyzing the clinical outcomes of neonatal brachial plexus palsy (NBPP) treated with a secondary soft-tissue shoulder operation. These researchers performed a literature search to identify studies of NBPP treated with a soft-tissue shoulder operation. A meta-analysis evaluated success rates for the aggregate Mallet score (greater than or equal to 4-point increase), global abduction score (greater than or equal to 1-point increase), and external rotation score (greater than or equal to 1-point increase) using the Mallet scale. Subgroup analysis was performed to assess these success rates when the author chose arthroscopic release technique versus open release technique with or without tendon transfer. Data from 17 studies and 405 patients were pooled for meta-analysis. The success rate for the global abduction score was significantly higher for the open technique (67.4 %) relative to the arthroscopic technique (27.7 %, p < 0.0001). The success rates for the global abduction score were significantly different among sexes (p = 0.01). The success rate for external rotation was not significantly different between the open (71.4 %) and arthroscopic techniques (74.1 %, p = 0.86). No other variable was found to have significant impact on the external rotation outcomes. The success rate for the aggregate Mallet score was 57.9 % for the open technique, a non-significant increase relative to the arthroscopic technique (53.5 %, p = 0.63). Data suggested a correlation between increasing age at the time of surgery and a decreasing likelihood of success with regards to aggregate Mallet with an odds ratio of 0.98 (p = 0.04). The authors concluded that overall, the secondary soft-tissue shoulder operation is an effective treatment for improving shoulder function in NBPP in appropriately selected patients. The open technique had significantly higher success rates in improving global abduction. There were no significant differences in the success rates for improvement in the external rotation or aggregate Mallet score among these surgical techniques.

Ali and colleagues (2014) stated that NBPP represents a significant health problem with potentially devastating consequences. The most common form of NBPP involves the upper trunk roots. Currently, primary surgical repair is performed if clinical improvement is lacking. There has been increasing interest in "early" surgical repair of NBPPs, occurring within 3 to 6 months of life. However, early treatment recommendations ignore spontaneous recovery in cases of Erb's palsy. This study was undertaken to evaluate the optimal timing of surgical repair in this group with respect to quality of life. These investigators formulated a decision analytical model to compare 4 treatment strategies (no repair or repair at 3, 6, or 12 months of life) for infants with persistent NBPPs. The model derived data from a critical review of published studies and projects health-related quality of life (QOL) and quality-adjusted life years (QALY) over a lifetime. When evaluating the QOL of infants with NBPP, improved outcomes were seen with delayed surgical repair at 12 months, compared with no repair or repair at early and intermediate time points, at 3 and 6 months, respectively. ANOVA showed that the differences among the 4 groups were highly significant (F = 8369; p < 0.0001). Pair-wise post-hoc comparisons revealed that there were highly significant differences between each pair of strategies (p < 0.0001). Meta-regression showed no evidence of improved outcomes with more recent treatment dates, compared with older ones, for either non-surgical or for surgical treatment (p = 0.767 and p = 0.865, respectively). The authors concluded that these data supported a delayed approach of primary surgical reconstruction to optimize QOL. They stated that early surgery for NBPPs may be an overly aggressive strategy for infants who would otherwise demonstrated spontaneous recovery of function by 12 months. They stated that a randomized, controlled trial would be needed to fully elucidate the natural history of NBPP and determine the optimal time point for surgical intervention.

Tse and colleagues (2015) stated that nerve transfers have gained popularity in the treatment of adult brachial plexus palsy; however, their role in the treatment of NBPP remains unclear. Brachial plexus palsies in infants differ greatly from those in adults in the patterns of injury, potential for recovery, and influences of growth and development. This International Federation of Societies for Surgery of the Hand committee report on NBPP was based upon review of the current literature. These investigators found no direct comparisons of nerve grafting to nerve transfer for primary reconstruction of NBPP. Although the results contained in individual reports that used each strategy for treatment of Erb palsy were similar, comparison of nerve transfer to nerve grafting was limited by inconsistencies in outcomes reported, by multiple confounding factors, and by small numbers of patients. Although the role of nerve transfers for primary reconstruction remains to be defined, nerve transfers have been found to be effective and useful in specific clinical circumstances including late presentation, isolated deficits, failed primary reconstruction, and multiple nerve root avulsions. In the case of NBPP more severe than Erb palsy, nerve transfers alone were inadequate to address all of the deficits and should only be considered as adjuncts if maximal re-innervation is to be achieved. The authors concluded that surgeons who commit to care of infants with NBPP need to avoid an over-reliance on nerve transfers and should also have the capability and inclination for brachial plexus exploration and nerve graft reconstruction.

An UpToDate review on "Brachial plexus syndromes" (Bromberg, 2015) states that "Management of neonatal brachial plexus palsy is controversial. A period of physical therapy and observation for evidence of recovery is often employed. Surgical intervention is advocated in select cases if functional recovery does not ensue in 3 to 9 months, but there is no consensus regarding the utility or timing of surgery. Early referral to a center with expertise in the management of NBPP may improve outcomes".

In a systematic review, Hinchcliff and colleagues (2021) examined the peer-reviewed literature on the morbidity of nerve transfers carried out in patients with brachial plexus birth injury (BPBI).  Nerve transfers for restoration of function in patients with BPBI that failed non-operative management are increasing in popularity; however, relatively little attention has been paid to the morbidity of these transfers in the growing patient.  These researchers systematically reviewed the current literature regarding donor site morbidity following nerve transfer for BPBI.  They carried out a systematic review of the Medline and Embase databases through February 2020.  Primary research articles written in English and reporting donor site morbidity after nerve transfer for BPBI were included for review.  A total of 36 articles met inclusion criteria, all of which were retrospective reviews or case reports.  There was great heterogeneity in outcomes assessed.  With 5 year or less follow-up, all transfers were relatively well-tolerated with the exception of the hypoglossal nerve transfer.  The authors concluded that nerve transfers were a well-recognized treatment strategy for patients with BPBI and had an acceptable risk profile in the short-term.  Full hypoglossal nerve transfers for BPBI were of historical interest; donor site morbidity was grossly underreported.  This review highlighted the need for more objective and systematic reporting of donor site outcomes, and the need for longer term follow-up in these patients.  Level of Evidence = III.

Morrow and associates (2021) noted that hand function outcomes of primary nerve reconstruction for total BPBI are confounded by nerve roots left in continuity, inclusion of secondary procedures, and no assessment of the ability to perform activities of daily living (ADL).  In a retrospective, single-center, case-series study, these researchers examined the long-term hand function outcomes in a cohort of patients with a complete BPBI who had no nerve root in continuity before primary nerve reconstruction targeting the lower trunk.  This trial included patients who underwent primary nerve reconstruction.  The outcomes were assessed using the AMS and brachial plexus outcome measure pre-operatively and at the age of 4 and 8 years.  A total of 50 patients with a complete BPBI, of whom 82 % (41/50) had an avulsion of C8 to T1, underwent primary nerve reconstruction at a mean age of 4.1 months.  Compared with the pre-operative AMS scores, a statistically significant increase of AMS scores was observed at 4 and 8 years of age for all movements except fore-arm pronation.  Between 4 and 8 years of age, there was a statistically significant improvement of external rotation of the shoulder and elbow flexion as well as diminution of thumb flexion.  In the brachial plexus outcome measure assessment, there were 83 % (24/29) at 4 years and 81 % (21/26) at 8 years who had sufficient functional movement to perform wrist, finger, and thumb activities.  The authors concluded that functional hand outcome was restored to sufficiently perform bi-manual activity tasks in 81 % (21/26) of patients with a complete BPBI at 8 years of age.  This affirmed that primary nerve reconstruction re-innervating the lower trunk could result in a functional extremity.  Level of Evidence = IV.

Bionic Reconstruction

Contralateral C7 Transfer for the Treatment of Traumatic Brachial Plexus Injury

The contralateral C7 nerve root is available as a donor for extraplexus transfer but is less optimal than ipsilateral transfers due to the long distance to regeneration (Elkwood, et al., 2019). 

Sammer and co-workers (2012) noted that in BPIs with nerve root avulsions, the options for nerve reconstruction are limited. In select situations, 50 % or all of the contralateral C7 (CC7) nerve root can be transferred to the injured side for brachial plexus reconstruction.  Although encouraging results have been reported, CC7 transfer has not gained universal popularity.  These researchers evaluated hemi-CC7 transfer for restoration of shoulder function or median nerve function in patients with severe BPI.  A retrospective review of all patients with traumatic BPI (TBPI) who had undergone hemi-CC7 transfer at a single institution during an 8-year period was performed.  Complications were evaluated in all patients regardless of the duration of follow-up.  The results of electro-diagnostic studies and modified British Medical Research Council (BMRC) motor grading were reviewed in all patients with more than 27 months of follow-up.  A total of 55 patients with TBPI underwent hemi-CC7 transfer performed between 2001 and 2008 for restoration of shoulder function or median nerve function; 13 patients who underwent hemi-CC7 transfer to the shoulder and 15patients who underwent hemi-CC7 transfer to the median nerve had more than 27 months of follow-up; 12/13 patients in the shoulder group demonstrated EMG evidence of re-innervation, but only 3 patients achieved M3 or greater shoulder abduction motor function; 3/15 patients in the median nerve group demonstrated EMG evidence of re-innervation, but none developed M3 or greater composite grip.  All patients experienced donor-side sensory or motor changes; these were typically mild and transient, but 1 patient sustained severe, permanent donor-side motor and sensory losses.  The authors concluded that the outcomes of hemi-CC7 transfer for restoration of shoulder motor function or median nerve function following post-TBPI do not justify the risk of donor-site morbidity, which includes possible permanent motor and sensory losses.

Chuang and Hernon (2012) stated that CC7 transfer for BPI can benefit finger sensation but remains controversial regarding restoration of motor function. These investigators reported their 20-year experience using CC7 transfer for BPI, all of which had at least 4 years of follow-up.  A total of 137 adult BPI patients underwent CC7 transfer from 1989 to 2006.  Of these patients, 101 fulfilled the inclusion criteria for this study.  A single surgeon performed all surgeries.  A vascularized ulnar nerve graft, either pedicled or free, was used for CC7 elongation.  The vascularized ulnar nerve graft was transferred to the median nerve (group 1, 1 target) in 55 patients, and to the median and musculo-cutaneous (MC) nerves (group 2, 2 targets) in 23 patients.  In another 23 patients (group 3, 2 targets, 2 stages), the CC7 was transferred to the median nerve (17 patients) or to the median and MC nerve (6 patients) during the 1st stage, followed by functioning free muscle transplantation (FFMT) for finger flexion.  These researchers considered finger flexion strength greater or equal to M3 to be a successful functional result.  Success rates of CC7 transfer were 55 %, 39 %, and 74 % for groups 1, 2, and 3, respectively.  In addition, the success rate for recovery of elbow flexion (strength M3 or better) in group 2 was 83 %.  The authors concluded that in reconstruction of total brachial plexus root avulsion, the best option may be to adopt the technique of using CC7 transfer to the MC and median nerve, followed by FFMT in the early stage (18 mo or less) for finger flexion.  They stated that such a technique can potentially improve motor recovery of elbow and finger flexion in a shorter rehabilitation period (3 to 4 years) and, more importantly, provide finger sensation to the completely paralytic limb.

Yang and colleagues (2015a) stated that CC7 transfer has been used for treating TBPI. However, the effectiveness of the procedure remains a subject of debate.  These investigators performed a systematic review to study the overall outcomes of CC7 transfer to different recipient nerves in TBPIs.  A literature search was conducted using PubMed and Embase databases to identify original articles related to CC7 transfer for TBPI.  The data extracted were study/patient characteristics, and objective outcomes of CC7 transfer to the recipient nerves.  These researchers normalized outcome measures into a MRC-based outcome scale.  A total of 39 studies were identified.  The outcomes were categorized based on the major recipient nerves: median, MC, and radial/triceps.  Regarding overall functional recovery, 11 % of patients achieved MRC grade M4 wrist flexion and 38 % achieved MRC grade M3.  Grade M4 finger flexion was achieved by 7 % of patients, whereas 36 % achieved M3.  Finally, 56 % achieved greater than or equal to S3 sensory recovery in the median nerve territories.  In the MC nerve group, 38 % regained to M4 and 37 % regained to M3.  In the radial/triceps nerve group, 25 %regained elbow or wrist extension strength to a MRC grade M4 and to M3, respectively.  The authors concluded that outcome measures in the included studies were not consistently reported to uncover true patient-related benefits from the CC7 transfer.  They stated that reliable and validated outcome instruments should be applied to critically evaluate patients undergoing CC7 transfer.

Yang and colleagues (2015b) noted that although CC7 transfer has been widely used for treating TBPI, the safety of the procedure is questionable. These investigators performed a systematic review to investigate the donor-site morbidity, including sensory abnormality and motor deficit, to guide clinical decision-making.  A systematic review on CC7 transfer for TBPI was performed for original articles in the PubMed and Embase databases.  Patient demographic data and donor-site morbidity of CC7 transfer, including incidence, recovery rate, and recovery time were extracted.  The sensory abnormality areas and muscles involved in motor weakness were also summarized.  A total of 904 patients from 27 studies were reviewed.  Overall, 74 % of patients (668 of 897) experienced sensory abnormalities, and 98 % (618 of 633) recovered to normal; the mean recovery time was 3 months.  For motor function, 20 % (118 of 592) had motor deficit after CC7 transfer and 91 % (107 of 117) regained normal motor function; the mean recovery time was 6 months.  Sensory abnormality mainly occurred in the area of the hand innervated by the median nerve, whereas motor deficit most often involved muscles innervated by the radial nerve.  There were 19 patients with long-term morbidity of the donor site in the studies.  The authors concluded that the incidence of donor-site morbidity after CC7 transfer was relatively high, and severe and long-term defects occurred occasionally.  They stated that CC7 transfer should be indicated only when other donor nerves are not available, and with a comprehensive knowledge of the potential risks.

Vu and associates (2018) stated that CC7 has been described for brachial plexus reconstruction in adults but has not been well-studied in the pediatric population.  In a retrospective review, these investigators presented their technique and results for retropharyngeal CC7 nerve transfer to the lower trunk for brachial plexus birth injury.  Any child aged less than 2 years was included.  Charts were analyzed for patient demographic data, operative variables, functional outcomes, complications, and length of follow-up.  A total of 5 patients were included in this study.  Average nerve graft length was 3 cm.  All patients had return of hand sensation to the ulnar nerve distribution as evidenced by a pinch test, unprompted use of the recipient limb without mirror movement, and an Active Movement Scale (AMS) of at least 2/7 for finger and thumb flexion; 1 patient had an AMS of 7/7 for finger and thumb flexion.  Only 1 patient had return of ulnar intrinsic hand function with an AMS of 3/7; 2 patients had temporary triceps weakness in the donor limb and 1 had clinically insignificant temporary phrenic nerve paresis.  No complications were related to the retropharyngeal nerve dissection in any patient.  Average follow-up was 3.3 years.  The authors concluded that the retropharyngeal CC7 nerve transfer was a safe way to supply extra axons to the severely injured arm in brachial plexus birth injuries with no permanent donor limb deficits.  They stated that early functional recovery in these patients, with regard to hand function and sensation, was promising.

Wang and colleagues (2018) noted that CC7 nerve root has been used as a donor nerve for targeted neurotization in the treatment of total brachial plexus palsy (TBPP).  These investigators studied the contribution of C7 to the innervation of specific upper-limb muscles and examined the utility of C7 nerve root as a recipient nerve in the management of TBPP.  This was a 2-part investigation.  First – anatomical study: the C7 nerve root was dissected and its individual branches were traced to the muscles in 5 embalmed adult cadavers bilaterally.  Second – clinical series: 6 patients with TBPP underwent CC7 nerve transfer to the middle trunk of the injured side.  Outcomes were evaluated with the modified Medical Research Council scale and EMG studies.  In the anatomical study there were consistent and predominantly C7-derived nerve fibers in the lateral pectoral, thoracodorsal, and radial nerves.  There was a minor contribution from C7 to the long thoracic nerve.  The average distance from the C7 nerve root to the lateral pectoral nerve entry point of the pectoralis major was the shortest, at 10.3 ± 1.4 cm.  In the clinical series the patients had been followed for a mean time of 30.8 ± 5.3 months post-operatively.  At the latest follow-up, 5 of 6 patients regained M3 or higher power for shoulder adduction and elbow extension; 2 patients regained M3 wrist extension.  All regained some wrist and finger extension, but muscle strength was poor.  Compound muscle action potentials were recorded from the pectoralis major at a mean follow-up of 6.7 ± 0.8 months; from the latissimus dorsi at 9.3 ± 1.4 months; from the triceps at 11.5 ± 1.4 months; from the wrist extensors at 17.2 ± 1.5 months; from the flexor carpi radialis at 17.0 ± 1.1 months; and from the digital extensors at 22.8 ± 2.0 months.  The average sensory recovery of the index finger was S2.  Transient paresthesia in the hand on the donor side, which resolved within 6 months post-operatively, was reported by all patients.  The authors concluded that the  C7 nerve root contributed consistently to the lateral pectoral nerve, the thoracodorsal nerve, and long head of the triceps branch of the radial nerve; CC7 to C7 nerve transfer is a reconstructive option in the overall management plan for TBPP.  It was safe and effective in restoring shoulder adduction and elbow extension in this patient series.  However, recoveries of wrist and finger extensions were poor.  These preliminary findings need to be further investigated.

Combined Human Acellular Nerve Allograft and Contralateral C7 Nerve Root Transfer for Restoring Shoulder Abduction and Elbow Flexion Following Brachial Plexus Injury

Li and colleagues (2019) noted that human acellular nerve allograft applications have increased in clinical practice, but no studies have quantified their influence on reconstruction outcomes for high-level, greater, and mixed nerves, especially the brachial plexus.  Ina retrospective study, these investigators examined the functional outcomes of human acellular nerve allograft reconstruction for nerve gaps in patients with BPI undergoing CC7 nerve root transfer to innervate the upper trunk, and they determined the independent predictors of recovery in shoulder abduction and elbow flexion.  A total of 45 patients with partial or total BPI were eligible for this trial after CC7 nerve root transfer to the upper trunk using human acellular nerve allografts.  Deltoid and biceps muscle strength, degree of shoulder abduction and elbow flexion, Semmes-Weinstein monofilament test, and static 2-point discrimination (S2PD) were examined according to the modified BMRC (mBMRC) scoring system, and disabilities of the arm, shoulder, and hand (DASH) were scored to establish the function of the affected upper limb.  Meaningful recovery was defined as grades of M3 to M5 or S3 to S4 based on the scoring system.  Subgroup analysis and univariate and multivariate logistic regression analyses were conducted to identify predictors of human acellular nerve allograft reconstruction.  The mean follow-up duration and the mean human acellular nerve allograft length were 48.1 ± 10.1 months and 30.9 ± 5.9 mm, respectively.  Deltoid and biceps muscle strength was grade M4 or M3 in 71.1 % and 60.0 % of patients.  Patients in the following groups achieved a higher rate of meaningful recovery in deltoid and biceps strength, as well as lower DASH scores (p < 0.01): age of less than 20 years and age 20 to 29 years; allograft lengths less than or equal to 30 mm; and patients in whom the interval between injury and surgery was less than 90 days.  The meaningful sensory recovery rate was approximately 70 % in the Semmes-Weinstein monofilament test and S2PD.  According to univariate and multivariate logistic regression analyses, age, interval between injury and surgery, and allograft length significantly influenced functional outcomes.  The authors concluded that human acellular nerve allografts offered safe reconstruction for 20- to 50-mm nerve gaps in procedures for CC7 nerve root transfer to repair the upper trunk after BPI.  The group in which allograft lengths were less than or equal to 30 mm achieved better functional outcome than others, and the recommended length of allograft in this procedure was less than 30 mm.  Age, interval between injury and surgery, and allograft length were independent predictors of functional outcomes following human acellular nerve allograft reconstruction.

Therapeutic Taping

Russo and colleagues (2016) examined if therapeutic taping for scapular stabilization affected scapula-thoracic, gleno-humeral, and humero-thoracic joint function in children with brachial plexus birth palsy and scapular winging. Motion capture data were collected with and without therapeutic taping to assist the middle and lower trapezius in 7 positions for 26 children.  Data were compared with 1-way multi-variate analyses of variance.  With therapeutic taping, scapular winging decreased considerably in all positions except abduction.  Additionally, there were increased gleno-humeral cross-body adduction and internal rotation angles in 4 positions.  The only change in humero-thoracic function was an increase of 3 degrees of external rotation in the external rotation position.  The authors concluded that therapeutic taping for scapular stabilization resulted in a small but statistically significant decrease in scapular winging.  Overall performance of positions was largely unchanged.  They stated that increased gleno-humeral joint angles with therapeutic taping may be beneficial for joint development; however, the long-term impact remains unknown.

Free Functioning Gracilis Muscle Transfer With Simultaneous Intercostal Nerve Transfer to Musculocutaneous Nerve for Restoration of Elbow Flexion After Traumatic Brachial Plexus Injury

Maldonado and colleagues (2017) stated that after complete 5-level root avulsion BPI, the free-functioning muscle transfer (FFMT) and the intercostal nerve (ICN) to musculocutaneous nerve (MCN) transfer are 2 potential reconstructive options for restoration of elbow flexion.  These investigators examined if the combination of the gracilis FFMT and the ICN to MCN transfer provides stronger elbow flexion compared with the gracilis FFMT alone.  A total of 65 patients who underwent the gracilis FFMT only (32 patients) or the gracilis FFMT in addition to the ICN to MCN transfer (33 patients) for elbow flexion after a pan-plexus injury were included.  The 2 groups were compared with respect to post-operative elbow flexion strength according to the modified British Medical Research Council grading system as well as pre-operative and post-operative Disability of the Arm, Shoulder, and Hand scores.  Two subgroup analyses were performed for the British Medical Research Council elbow flexion strength grade: FFMT neurotization (spinal accessory nerve versus ICN) and the attachment of the distal gracilis tendon (biceps tendon versus flexor digitorum profundus/flexor pollicis longus tendon).  The proportion of patients reaching the M3/M4 elbow flexion muscle grade were similar in both groups (FFMT versus FFMT + ICN to MCN transfer).  Statistically significant improvement in post-operative Disability of the Arm, Shoulder, and Hand score was found in the FFMT + ICN to MCN transfer group but not in the FFMT group.  There was a significant difference between gracilis to biceps (M3/M4 = 52.6 %) and gracilis to FDP/flexor pollicis longus (M3/M4 = 85.2 %) tendon attachment.  The authors concluded that the use of the ICN to MCN transfer associated with the FFMT did not improve the elbow flexion modified British Medical Research Council grade, although better post-operative Disability of the Arm, Shoulder, and Hand scores were found in this group.  The more distal attachment of the gracilis FFMT tendon may play an important role in elbow flexion strength.

In a systematic review, Oliver and colleagues (2020) compared post-operative elbow flexion outcomes in patients receiving functioning free muscle transplantation (FFMT) innervated by either intercostal nerve (ICN) or spinal accessory nerve (SAN) grafts.  These researchers carried out a comprehensive systematic review on FFMT for brachial plexus reconstruction using Medline/PubMed data-base.  Analysis was designed to compare functional outcomes between nerve graft type (ICN versus SAN) as well as different free muscle graft types to biceps tendon (gracilis versus rectus femoris versus latissimus dorsi).  A total of 312 FFMTs innervated by ICNs (169) or the SAN (143) were featured in 10 case series.  The mean patient age was 28 years.  Patients had a mean injury to surgery time of 31.5 months and an average follow-up time of 39.1 months with 18 patients lost to follow-up.  Muscles utilized included the gracilis (275), rectus femoris (28), and latissimus dorsi (8).  After excluding those lost to follow-up or failures due to vascular compromise, the mean success rates of FFMTs innervated by ICNs and SAN were 64.1 % and 65.4 %, respectively.  The authors concluded that this analysis did not identify any difference in outcomes between FFMTs via ICN grafts and those innervated by SAN grafts in restoring elbow flexion in traumatic brachial plexus injury patients.

Oberlin Transfer for Improving Early Supination in Neonatal Brachial Plexus Palsy

The ulnar to musculocutaneous nerve transfer (ie, Oberlin) involves the transposition of fascicles of the flexor carpi ulnaris to the biceps branch of musculocutaneous nerve [40].

Chang and associates (2018a) noted that the use of nerve transfers versus nerve grafting for NBPP remains controversial.  In adult BPI, transfer of an ulnar fascicle to the biceps branch of the musculo-cutaneous nerve (Oberlin transfer) is reportedly superior to nerve grafting for restoration of elbow flexion.  In pediatric patients with NBPP, recovery of elbow flexion and forearm supination is an indicator of resolved NBPP.  Currently, limited evidence exists of outcomes for flexion and supination when comparing nerve transfer and nerve grafting for NBPP.  In a retrospective, cohort study, these researchers compared 1-year post-operative outcomes for infants with NBPP who underwent Oberlin transfer versus nerve grafting.  This trial reviewed patients with NBPP who underwent Oberlin transfer (n = 19) and nerve grafting (n = 31) at a single institution between 2005 and 2015.  A single surgeon conducted intra-operative exploration of the brachial plexus and determined the surgical nerve reconstruction strategy undertaken.  Active range of motion (ROM) was evaluated pre-operatively and post-operatively at 1 year.  No significant difference between treatment groups was observed with respect to the mean change (pre- to post-operatively) in elbow flexion in adduction and abduction and biceps strength.  The Oberlin transfer group gained significantly more supination (100° versus 19°; p < 0.0001).  Forearm pronation was maintained at 90° in the Oberlin transfer group whereas it was slightly improved in the grafting group (0° versus 32°; p = 0.02).  Shoulder, wrist, and hand functions were comparable between treatment groups.  The authors concluded that these preliminary data demonstrated that the Oberlin transfer conferred an advantageous early recovery of forearm supination over grafting, with equivalent elbow flexion recovery.  Moreover, they stated that further studies that monitor real-world arm usage will provide more insight into the most appropriate surgical strategy for NBPP.

Double Fascicular Nerve Transfer to Musculocutaneous Branches for Restoring Elbow Function Following Brachial Plexus Injury

The Oberlin transfer can be combined with the median nerve branch to brachialis branch of the musculocutaneous nerve (Mackinnon or double transfer) (Mackinnon, et al., 2005; Elkwood, et al, 2019). The average time to reinnervation in these transfers is five months, which is considerably shorter than plexus reconstruction using interposition grafts.

Mackinnon, et al (2005) reported on a double fascicular nerve transfer to reinnervate the brachialis muscle and the biceps muscle to restore elbow flexion after brachial plexus injury. A retrospective review was performed on 6 patients who had direct nerve transfer of a single expendable motor fascicle from both the ulnar and median nerves directly to the biceps and brachialis branches of the musculocutaneous nerve. Assessment included degree of recovery of elbow flexion and ulnar and median nerve function including pinch and grip strengths. Clinical evidence of reinnervation was noted at a mean of 5.5 months (SD, 1 mo; range, 3.5-7 mo) after surgery and the mean follow-up period was 20.5 months (SD, 11.2 mo, range, 13-43 mo). Mean recovery of elbow flexion was Medical Research Council grade 4+. Postoperative pinch and grip strengths were unchanged or better in all patients. No motor or sensory deficits related to the ulnar or median nerves were noted and all patients maintained good hand function. No patients required additional procedures to further improve elbow flexion strength.

Texakalidis and colleagues (2019) noted that restriction of elbow flexion significantly limits upper extremity (UE) function following BPI.  In recent years, the double fascicular nerve transfer procedure utilizing ulnar and median nerve transfer to musculocutaneous branches has shown promising functional outcomes.  In a retrospective review, these investigators examined restoration of elbow flexion following a double fascicular transfer in patients with BPI and identified predictors of poor outcomes.  This review included 10 consecutive patients with BPI involving C5 to C6 root avulsions who underwent the double nerve transfer procedure.  The mean follow-up was 12 months and the primary outcome was assessment of elbow flexion with the use of the MRC scale.  This procedure achieved elbow flexion of MRC grade M3 or higher in 50 % of this cohort.  Time interval from injury to surgery showed a statistically significant inverse association with functional recovery (r = -0.73, p = 0.016).  Patients who had the surgery within 6 months of the injury, demonstrated higher MRC grades during the follow-up (p = 0.048).  There was no association between elbow flexion recovery and age, body mass index (BMI), gender, hypertension, diabetes or smoking status.  The authors concluded that the findings of the current study suggested that the double ulnar and median nerve transfer to the musculocutaneous may be a safe and effective approach for elbow flexion restoration following C5 to C6 root avulsions.  Furthermore, it noted that functional outcomes were adversely affected by the increase in the time interval from injury to surgery; the double fascicular transfer within the first 6 months was suggested by this study.  No association between MRC grades and patient demographic characteristics was identified.

The authors stated that this study had several drawbacks.  First, this study was retrospective, and thus limited by its non-randomized nature.  Second, despite the standardized follow-up schedule at the authors’ institution, its duration was not similar for all patients due to some patients missing appointments, which might have affected the outcomes.  Third, this study was limited by its small sample size (n = 10), single surgeon experience and lack of matched controls.

Vascularized Brachial Plexus Allo-Transplantation for the Treatment of Traumatic Brachial Plexus Injury

Chang and colleagues (2019) stated that brachial plexus injuries are devastating.  Current reconstructive treatments achieve limited partial functionality.  Vascularized brachial plexus allo-transplantation could offer the best nerve graft fulfilling the like-with-like principle.  In this experimental study, these researchers examined the feasibility of rat brachial plexus allo-transplantation and analyzed its functional outcomes.  A free vascularized brachial plexus with a chimeric compound skin paddle flap based on the subclavian vessels was transplanted from a Brown Norway rat to a Lewis rat.  This study has 2 parts.  Protocol I aimed to develop the vascularized brachial plexus allo-transplantation-model (VBP-allo); 4 groups were compared: no reconstruction, VBP-allo with and without cyclosporine-A (CsA) immunosuppression, VBP auto-transplantation (VBP-auto).  Protocol II compared the recovery of the biceps muscle and forearm flexors when using all 5, 2 (C5+C6) or 1 (isolated C6) spinal nerve as the donor nerves.  The assessment was performed on week 16 and included muscle weight, functionality (grooming tests, muscle strength), electrophysiology and histomorphology of the targeted muscles.  Protocol I showed, the VBP-allo with CsA immunosuppression was electrophysiologically and functionally comparable to VBP-auto and significantly superior to negative controls and absent immunosuppression.  In Protocol II, all groups had a comparable functional recovery in the biceps muscle.  Only with 5 donor nerves did the forearm show good results compared with only 1 or 2 donor nerves.  The authors concluded that the findings of this study showed an useful vascularized complete brachial plexus allo-transplantation rodent model with successful forelimb function restoration under immunosuppression.  Only the allo-transplantation including all 5 roots as donor nerves achieved a forearm recovery.

Combined Flexor Carpi Ulnaris and Flexor Carpi Radialis Transfer for Restoring Elbow Function Following Brachial Plexus Injury

Atthakomol and colleagues (2019) stated that the result of combined agonist and antagonist muscle innervation in TBPI through the intraplexal fascicle nerve transfers with the same donor function has not yet been reported.  These researchers described a patient with a C5 to C7 TBPI who had a combined transfer of the flexor carpi radialis (FCR) fascicle to the musculocutaneous nerve and the flexor carpi ulnaris (FCU) fascicle to the radial nerve of the triceps.  The patient returned for his follow-up visit 2 years after his surgery.  The muscle strengths of his triceps and biceps were MRC grade 2 and 0, respectively.  Compared with his uninjured side, his grip strength was 9.8 %, and his pinch strength was 14.2 %.  The authors concluded that this case report provided insights on result of combined agonist and antagonist muscle innervation through combining the motor fascicle of the FCR and FCU to restore the elbow flexor and extensor; the result may not be promising.

Optimal Donor Nerve to Restore Elbow Flexion After Traumatic Brachial Plexus Injury

Kang et al (2020) noted that the neural surgical options for reconstruction of elbow flexion in BPIs depend on the availability of nerve donors.  In upper-type avulsion injuries, the ulnar or median nerves, when intact, are reliable intra-plexal donor nerves for transfers to the biceps muscle.  In complete avulsion injuries, donors are limited to extra-plexal sources, such as intercostal nerves (ICNs).  These investigators reviewed their results of ICN and partial distal nerve (ulnar or median) transfers for elbow flexion reconstruction in patients with brachial plexus avulsion injuries.  The time taken for recovery of elbow flexion strength to M3 and the final motor outcome at 2 years were compared between both groups.  A total of 38 patients were included in this study -- 27 had ICN transfers to the musculocutaneous nerve (MCN), 8 had partial ulnar nerve transfers and 3 had partial median nerve transfers to the MCN's biceps motor branch.  The mean time interval from injury to surgery was 3.6 months.  Recovery of elbow flexion was observed earlier in the distal nerve transfer group (p < 0.05).  Overall, success rates were higher in patients with distal nerve transfers (100 %), compared to ICN transfers (63 %) at 2 years (p = 0.018).  Patients with distal nerve transfers achieved a higher final median strength of M4.0 (inter-quartile range (IQR) 3.5 to 4.5), compared to M3.5 (IQR 2.0 to 4.0) in the ICN group (p = 0.031) . In the subgroup of patients with upper-type BPIs, there were no significant differences in motor outcomes between the ICN versus distal nerve transfers group.  The authors concluded that in their entire cohort, patients with distal nerve transfers had faster motor recovery and better elbow flexion power than patients with ICN transfers.  In patients with partial BPIs, outcomes of ICN transfers were not inferior to distal nerve transfers.

Kim et al (2022) stated that TBPIs often result in devastating deficits in the UE; treatment frequently prioritizes restoring elbow flexion via transfer of various donor nerves.  However, no consensus identifies optimal donor nerve sources.  In a meta-analysis, these investigators examined donor nerves for restoring elbow flexion following partial BPI and TBPI.  Original English language articles on nerve transfers to restore elbow flexion following BPI were included.  Using a random-effects model, these researchers calculated pooled, weighted effect size of the patients achieving a composite motor score of M3 or higher, with subgroup analyses for patients achieving M4 strength and with TBPI.  Meta-regression was carried out to evaluate comparative effectiveness of each donor nerve for these outcomes.  Comparison of the overall effect size of the 61 included articles showed that ICNs and phrenic nerves were statistically superior to contralateral C7 (cC7; p = 0.025, < 0.001, respectively) in achieving M3 or higher strength.  After stratification by TBPI, the phrenic nerve was still superior to cC7 in achieving M3 or higher strength (p = 0.009).  There were no statistical differences among ulnar, double fascicle, or medial pectoral nerves in achieving M3 or higher strength.  Regarding M4 strength, the phrenic nerve was superior to cC7 (p = 0.01) in patients with TBPI and the ulnar nerve was superior to the medial pectoral nerve (p = 0.036) for partial BPI.  The authors concluded that neurotization of partial BPI or TBPI via the ICN or phrenic nerve may result in functional advantage over cC7.  In patients with upper trunk injuries, neurotization using ulnar, median, or double fascicle nerve transfers has similarly excellent functional recovery.

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References