Nerve transfer to deltoid muscle using the nerve to the long head of the triceps, part I: an anatomic feasibility study

Outcomes of surgically managed adult traumatic brachial plexus injuries in an upper-middle-income country

Background

Traumatic brachial plexus injuries (TBPIs) are debilitating and complex to treat. The last five decades have seen advances in surgical management, and consequently improved functional outcomes in patients with these injuries. There is limited data available describing the outcomes of surgically managed TBPIs within the South African context. This study aimed to identify the common causes of injury, injury characteristics, and functional outcomes of surgically managed patients with TBPIs.

Methods

We conducted a retrospective chart review of all adult patients that underwent surgery for TBPIs over a period of ten years at a specialised hand unit in South Africa. The minimum follow-up period was one year. Patient demographic details, injury characteristics and functional outcomes were collected. Statistical analysis was performed to determine factors associated with functional outcomes. A good functional outcome for recovery was defined as a Medical Research Council (MRC) grade of three or more for the affected elements of the plexus at the most recent follow-up.

Results

Forty-seven patients of median age 32 years were included in the final analysis. Most patients were male (87.2 %). The majority of patients were injured in motor vehicle accidents (MVAs) or from penetrating stab wounds (48.9 % and 38.3 % respectively). The median pre-operative MRC grade of the affected elements of the brachial plexus was 0.0, and post-operatively was 2.0. Fourteen patients (14 of 47, 29.8 %) had a good outcome and 33 had a poor outcome (33 of 47, 70.2 %). There was no difference in outcome comparing penetrating injury mechanisms to closed traction or blunt injuries, (p = 0.386, OR 1.75, 95 % CI 0.49-6.20). All patients with pan-plexal injuries had a poor outcome (15 of 33, 46 %). All patients who received intercostal (6 of 33, 18 %) or phrenic nerve transfers (3 of 33, 9 %) had a poor outcome.

Conclusion

Adult traumatic BPIs in this South African sample typically presented more than two months after injury and were comprised of a high proportion of penetrating injuries. Just under a third of surgically managed patients had a good outcome. Pan plexal injuries have uniformly poor outcomes. We recommend early referral for all TBPIs to a unit that manages BPI to improve outcomes.

Posterior Deltoid Function After Transfer of Branch to the Long Head Triceps Brachii of the Radial Nerve to the Anterior Branch of the Axillary Nerve

PURPOSE

The aim of this study was to evaluate the function of the posterior part of the deltoid after nerve transfer of the long head triceps branch of the radial nerve to the anterior branch of the axillary nerve in patients with an upper brachial plexus injury or isolated axillary nerve injury.

METHODS

We retrospectively reviewed 26 patients diagnosed with an upper brachial plexus injury or isolated axillary nerve injury who underwent nerve transfer of the long head triceps muscle branch of the radial nerve to the anterior branch of the axillary nerve in our institute between 2012 and 2017. Data on age, sex, the mechanism of injury, the pattern of injury, and operative treatment were collected from medical records. Preoperative and postoperative clinical examinations, including motor powers of shoulder abduction and extension according to Medical Research Council grading, were evaluated. At a minimum of 2 years after the operation, we evaluated the recovery of the posterior deltoid function using the swallow-tail test.

RESULTS

Twenty-two patients (84.6%) had recovery of posterior deltoid function confirmed by the swallow-tail test. There were 23 patients (88.5%) who achieved at least Medical Research Council grade 4 of shoulder abduction.

CONCLUSIONS

Nerve transfer from the branch to the long head triceps to the anterior branch of the axillary nerve is an effective technique for restoring deltoid function in an upper brachial plexus injury or isolated axillary nerve injury. This technique can provide shoulder abduction and shoulder extension, which are the functions of the posterior deltoid muscle.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

A Surgical Framework for the Management of Incomplete Axillary Nerve Injuries

BACKGROUND

 Axillary nerve injury is the most common nerve injury affecting shoulder function. Nerve repair, grafting, and/or end-to-end nerve transfers are used to reconstruct complete neurotmetic axillary nerve injuries. While many incomplete axillary nerve injuries self-resolve, axonotmetic injuries are unpredictable, and incomplete recovery occurs. Similarly, recovery may be further inhibited by superimposed compression neuropathy at the quadrangular space. The current framework for managing incomplete axillary injuries typically does not include surgery.

METHODS

 This study is a retrospective analysis of 23 consecutive patients with incomplete axillary nerve palsy who underwent quadrangular space decompression with additional selective medial triceps to axillary end-to-side nerve transfers in 7 patients between 2015 and 2019. Primary outcome variables included the proportion of patients with shoulder abduction M3 or greater as measured on the Medical Research Council (MRC) scale, and shoulder pain measured on a Visual Analogue Scale (VAS). Secondary outcome variables included pre- and postoperative Disabilities of the Arm, Shoulder, and Hand Questionnaire (DASH) scores.

RESULTS

 A total of 23 patients met the inclusion criteria and underwent nerve surgery a mean 10.7 months after injury. Nineteen (83%) patients achieved MRC grade 3 shoulder abduction or greater after intervention, compared with only 4 (17%) patients preoperatively (p = 0.001). There was a significant decrease in VAS shoulder pain scores of 4.2 ± 2.5 preoperatively to 1.9 ± 2.4 postoperatively (p < 0.001). The DASH scores also decreased significantly from 48.8 ± 19.0 preoperatively to 30.7 ± 20.4 postoperatively (p < 0.001). Total follow-up was 17.3 ± 4.3 months.

CONCLUSION

 A surgical framework is presented for the appropriate diagnosis and surgical management of incomplete axillary nerve injury. Quadrangular space decompression with or without selective medial triceps to axillary end-to-side nerve transfers is associated with improvement in shoulder abduction strength, pain, and DASH scores in patients with incomplete axillary nerve palsy.

The Clinical Outcomes of Spinal Accessory to Suprascapular Nerve Transfer Through a Posterior Approach

BACKGROUND

Spinal accessory nerve (SAN) to suprascapular nerve (SSN) transfer can restore function to the rotator cuff following brachial plexus injuries. The traditional anterior approach using the lateral branch of the SAN causes denervation of the lateral trapezius limiting shoulder elevation. Suprascapular nerve pathology at the suprascapular notch may be missed resulting in poor reinnervation of the rotator cuff. The posterior approach uses the medial SAN and allows decompression and visualization of the SSN at the notch and nerve transfer coaptation closer to the target muscles with a shorter reinnervation distance.

METHODS

This is a review of 28 patients from 2014 to February 2020 who underwent SAN to SSN nerve transfer via a posterior approach. Patients were evaluated for SSN pathology, external rotation power, and range of motion. Data were evaluated for high-energy trauma (HET) and low-energy trauma/nontraumatic etiology subsets.

RESULTS

A total of 8 HET (40%) patients had pathology identified at the suprascapular notch during the posterior approach, including SSN scarring, ruptures, neuromata-in-continuity, and ossification of ligaments. British Medical Research Council grade greater than or equal to 4 shoulder external rotation was achieved in 75% patients with median range of motion 137.5°.

CONCLUSIONS

Spinal accessory nerve to SSN transfer using a posterior approach allows visualization of pathology involving the SSN and coaptation of a medial SAN transfer close to the target muscles. Following HET, 8 cases (40%) had posterior pathology identified. Spinal accessory nerve to SSN transfer through a posterior approach shows improved external rotation power and range of motion.

The surgical anatomy of the axillary approach for nerve transfer procedures targeting the axillary nerve

PURPOSE

The exact relational anatomy for the anterior axillary approach, targeting the axillary nerve for nerve transfers/grafts, has not been fully investigated. Therefore, this study aimed to dissect and document the gross anatomy surrounding this approach, specifically regarding the axillary nerve and its branches.

METHODS

Fifty-one formalin-fixed cadavers (98 axilla) were bilaterally dissected simulating the axillary approach. Measurements were taken to quantify distances between identifiable anatomical landmarks and relevant neurovascular structures encountered during this approach. The musculo-arterial triangle, described by Bertelli et al., to aid in identification on localization of the axillary nerve, was also assessed.

RESULTS

From the origin of the axillary nerve till (1) latissimus dorsi was 62.3 ± 10.7 mm and till (2) its division into anterior and posterior branches was 38.8 ± 9.6 mm. The origin of the teres minor branch along the posterior division of the axillary nerve was recorded as 6.4 ± 2.9 mm in females and 7.4 ± 2.8 mm in males. The musculo-arterial triangle reliably identified the axillary nerve in only 60.2% of the sample.

CONCLUSION

The results clearly demonstrate that the axillary nerve and its divisions can be easily identified with this approach. The proximal axillary nerve, however, was situated deep and therefore challenging to expose. The musculo-arterial triangle was relatively successful in localising the axillary nerve, however, more consistent landmarks such as the latissimus dorsi, subscapularis, and quadrangular space have been suggested. The axillary approach may serve as a reliable and safe method to reach the axillary nerve and its divisions, allowing for adequate exposure when considering a nerve transfer or graft.

Trends in Brachial Plexus Surgery: Characterizing Contemporary Practices for Exploration of Supraclavicular Plexus

BACKGROUND

There is variability in treatment strategies for patients with brachial plexus injury (BPI). We used qualitative research methods to better understand surgeons' rationale for treatment approaches. We hypothesized that distal nerve transfers would be preferred over exploration and nerve grafting of the brachial plexus.

METHODS

We conducted semi-structured interviews with BPI surgeons to discuss 3 case vignettes: pan-plexus injury, upper trunk injury, and lower trunk injury. The interview guide included questions regarding overall treatment strategy, indications and utility of brachial plexus exploration, and the role of nerve grafting and/or nerve transfers. Interview transcripts were coded by 2 researchers. We performed inductive thematic analysis to collate these codes into themes, focusing on the role of brachial plexus exploration in the treatment of BPI.

RESULTS

Most surgeons routinely explore the supraclavicular brachial plexus in situations of pan-plexus and upper trunk injuries. Reasons to explore included the importance of obtaining a definitive root level diagnosis, perceived availability of donor nerve roots, timing of anticipated recovery, plans for distal reconstruction, and the potential for neurolysis. Very few explore lower trunk injuries, citing concern with technical difficulty and unfavorable risk-benefit profile.

CONCLUSIONS

Our analysis suggests that supraclavicular exploration remains a foundational component of surgical management of BPI, despite increasing utilization of distal nerve transfers. Availability of abundant donor axons and establishing an accurate diagnosis were cited as primary reasons in support of exploration. This analysis of surgeon interviews characterizes contemporary practices regarding the role of brachial plexus exploration in the treatment of BPI.

Factors Associated with Poorer Outcomes from Triceps Motor Branch to Anterior Axillary Nerve Transfer: A Case-Control Study

INTRODUCTION

We sought to identify predictors of failed triceps motor branch transfer to the anterior division of the axillary nerve (AN) for shoulder abduction reconstruction after a brachial plexus injury (BPI).

METHODS

A case-control study of adult AN or brachial plexus patients treated with a triceps motor branch transfer to the anterior division of the AN with a minimum 18 months of follow-up was performed. The failure group (case group) was defined as modified British Medical Research Council muscle scale (mBMRC) postoperative deltoid grade ≤2 and was compared to the successful outcome group (control group), defined as mBMRC postoperative deltoid grade ≥3. Clinical variables, injury mechanism, time from injury to surgery, root avulsion status, electrodiagnostic studies, rotator cuff injuries, scapula fracture, Disabilities of the Arm Shoulder and Hand scores, and preoperative triceps strength were analyzed. Subgroup analysis was performed for patients with isolated AN injuries and those with BPI.

RESULTS

A total of 69 patients met inclusion/exclusion criteria, of whom 23 regained ≥M3 deltoid muscle strength and 52° ± 69° of shoulder abduction (successful outcome group) and 46 regained ≤M2 deltoid muscle strength and 27° ± 30° of shoulder abduction (failure group). Preoperative triceps weakness (M ≤4) was significantly more common in the failure group (63% vs. 30%, P = 0.032); preoperative triceps muscle fibrillations were significantly more common in the failure group (61% vs. 30%, P = 0.02). Isolated AN injuries presented better preoperative motion and postoperative outcomes results compared to BPI.

CONCLUSIONS

Use of triceps motor branch associated with fibrillations or weakness resulted in statistically poorer outcomes compared to the use of a normal triceps motor branch in the restoration of anterior AN function after nerve transfer.

Morbidity of long head of the triceps motor branch neurotization to the axillary nerve: Retrospective subjective and objective assessment of triceps brachii strength after transfer

INTRODUCTION

Morbidity is considered to be negligible in Leechavengvongs transfer (LT) of the long head of the triceps onto the axillary nerve, but the assessment methods used may lack reproducibility. We assessed triceps strength after LT objectively by the isokinetic technique, addressing the following questions: Is strength lowered after LT compared to the healthy limb? And 2) is there a good correlation between isokinetic dynamometry and subjective assessment?

HYPOTHESIS

Isokinetic measurement shows a decrease in triceps strength at peak torque after LT compared to the healthy limb, and this morbidity is underestimated on subjective assessment.

MATERIAL AND METHODS

This single-center retrospective study included patients undergoing LT for axillary nerve trunk palsy between 2008 and 2020, with M5 triceps preoperatively on the British Medical Research Council (BMRC) scale. Twenty patients, with a mean age of 25±9years (range, 15-48years) were assessed at a mean 58±47months (range, 6-174months). Elbow extension strength was assessed on a standardized questionnaire, BMRC isometric test and isokinetic test on an angular course of 90° at 60°/sec and 180°/sec concentrically and 30°/sec excentrically.

RESULTS

Strength at 60°/sec and 180°/sec concentrically and 30°/sec excentrically was significantly lower than in the healthy limb: respectively, -17Nm, -15Nm, and -16Nm, (p<0.001) for a mean -23%. Loss of strength was mainly severe on isokinetic testing and mild on isometric testing. Seven patients reported contracture (35%), 12 fatigue (60%), and 3 weakness (15%). Satisfaction with extension strength was excellent or good for respectively 12 (60%) and 8 patients (40%). Triceps strength was graded BMRC M4 in 9 triceps (11%) and M5 in 11 (55%).

DISCUSSION

After LT, isokinetic measurement found generally severe loss of triceps strength, but without subjective impact on everyday life.

LEVEL OF EVIDENCE

IV; retrospective study.

Outcome Analysis of Medial Triceps Motor Nerve Transfer to Axillary Nerve in Isolated and Brachial Plexus-Associated Axillary Nerve Palsy

BACKGROUND

Since 2007, the authors have performed the triceps-to-axillary nerve transfer using the medial triceps branch to reconstruct axillary nerve function in brachial plexus and isolated axillary nerve palsies.

METHODS

A retrospective chart review was undertaken of patients reconstructed with this transfer, recording patient and injury demographics and time to surgery. Preoperative and postoperative function was graded using the Medical Research Council scale and the Disabilities of the Arm, Shoulder, and Hand questionnaire.

RESULTS

Postoperatively, 31 patients (64.6 percent) reached Medical Research Council grade 3 or higher at final follow-up. The median Disabilities of the Arm, Shoulder, and Hand score was 59.9 (interquartile range, 38.8 to 70.5) preoperatively and 25.0 (interquartile range, 11.3 to 61.4) at final follow-up. Sixteen patients (33 percent) had isolated axillary nerve injury; the median Medical Research Council grade was 4.25 (interquartile range, 3 to 4.25), with 14 patients (87.6 percent) achieving grade 3 or higher. Thirty-two patients (77 percent) had brachial plexus-associated injury; median Medical Research Council grade was 3 (interquartile range, 2 to 3), with 17 patients (53.1 percent) achieving grade 3 or higher.

CONCLUSION

Medial triceps nerve branch is a strong donor for triceps-to-axillary nerve transfer; however, injury factors may limit the motor recovery in this complex patient population, particularly in axillary nerve palsy associated with brachial plexus injury.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Triceps and cutaneous radial nerve branches investigated via an axillary anterior arm approach: new findings in a fresh-cadaver anatomical study

OBJECTIVE

The authors sought to describe the anatomy of the radial nerve and its branches when exposed through an axillary anterior arm approach.

METHODS

Bilateral upper limbs of 10 fresh cadavers were dissected after dyed latex was injected into the axillary artery.

RESULTS

Via the anterior arm approach, all triceps muscle heads could be dissected and individualized. The radial nerve overlaid the latissimus dorsi tendon, bounded by the axillar artery on its superior surface, then passed around the humerus, together with the lower lateral arm and posterior antebrachial cutaneous nerve, between the lateral and medial heads of the triceps. No triceps motor branch accompanied the radial nerve's trajectory. Over the latissimus dorsi tendon, an antero-inferior bundle, containing all radial nerve branches to the triceps, was consistently observed. In the majority of the dissections, a single branch to the long head and dual innervations for the lateral and medial heads were observed. The triceps long and proximal lateral head branches entered the triceps muscle close to the latissimus dorsi tendon. The second branch to the lateral head stemmed from the triceps lower head motor branch. The triceps medial head was innervated by the upper medial head motor branch, which followed the ulnar nerve to enter the medial head on its anterior surface. The distal branch to the triceps medial head also originated near the distal border of the latissimus dorsi tendon. After a short trajectory, a branch went out that penetrated the medial head on its posterior surface. The triceps lower medial head motor branch ended in the anconeus muscle, after traveling inside the triceps medial head. The lower lateral arm and posterior antebrachial cutaneous nerve followed the radial nerve within the torsion canal. The lower lateral brachial cutaneous nerve innervated the skin over the biceps, while the posterior antebrachial cutaneous nerve innervated the skin over the lateral epicondyle and posterior surface of the forearm. The average numbers of myelinated fibers were 926 in the long and 439 in the upper lateral head and 658 in the upper and 1137 in the lower medial head motor branches.

CONCLUSIONS

The new understanding of radial nerve anatomy delineated in this study should aid surgeons during reconstructive surgery to treat upper-limb paralysis.

Pathological findings identified during the posterior approach to the spinal accessory nerve after high-energy trauma

The spinal accessory to suprascapular nerve transfer is a key procedure for restoring shoulder function in upper brachial plexus injuries and is typically undertaken via an anterior approach. The anterior approach may miss injury to the suprascapular nerve about the suprascapular notch, which may explain why functional outcomes are often limited. In 2014 we adopted a posterior approach to enable better visualization of the suprascapular nerve at the notch. Over the next 6 years we have used this approach for 20 explorations after high-energy trauma. In 7/20 we identified abnormalities at the level of the suprascapular ligament, which we would not have identified with an anterior approach: there were two ruptures, two neuromas-in-continuity and three cases of scar encasement, necessitating neurolysis. Nerve transfer could be undertaken distal to the suprascapular notch, bypassing the site of injury. These pathological findings support the wider adoption of the posterior approach in cases of high-energy trauma.Level of evidence: IV.

Considerations in the Selection of Donor Nerves for Nerve Transfer for Reanimation of Elbow and Shoulder in Traumatic Brachial Plexus Injuries

The advent of nerve transfers has revolutionised the treatment of brachial plexus and peripheral nerve injuries of the upper extremity. Nerve transfers offer faster reinnervation of a denervated muscle by taking advantage of a donor nerve, branch or fascicle close to the recipient muscle. A number of considerations in respect of donor selection for nerve transfers underlie their success. In this review article, we discuss the principles of donor selection for nerve transfers, the different options available and our considerations in choosing a suitable transfer in reanimating the elbow and the shoulder. We feel this will help nerve surgeons navigate the controversies in the selection of donor nerves and make appropriate treatment decisions for their patients. Level of Evidence: V (Therapeutic).

Possible donor nerves for axillary nerve reconstruction in dual neurotization for restoring shoulder abduction in brachial plexus injuries: a systematic review and meta-analysis

Restoring shoulder abduction is one of the main priorities in the surgical treatment of brachial plexus injuries. Double nerve transfer to the axillary nerve and suprascapular nerve is widely used and considered the best option. The most common donor nerve for the suprascapular nerve is the spinal accessory nerve. However, donor nerves for axillary nerve reconstructions vary and it is still unclear which donor nerve has the best outcome. The aim of this study was to perform a systematic review on reconstructions of suprascapular and axillary nerves and to perform a meta-analysis investigating the outcomes of different donor nerves on axillary nerve reconstructions. We conducted a systematic search of English literature from March 2001 to December 2020 following PRISMA guidelines. Two outcomes were assessed, abduction strength using the Medical Research Council (MRC) scale and range of motion (ROM). Twenty-two studies describing the use of donor nerves met the inclusion criteria for the systematic review. Donor nerves investigated included the radial nerve, intercostal nerves, medial pectoral nerve, ulnar nerve fascicle, median nerve fascicle and the lower subscapular nerve. Fifteen studies that investigated the radial and intercostal nerves met the inclusion criteria for a meta-analysis. We found no statistically significant difference between either of these nerves in the abduction strength according to MRC score (radial nerve 3.66 ± 1.02 vs intercostal nerves 3.48 ± 0.64, p = 0.086). However, the difference in ROM was statistically significant (radial nerve 106.33 ± 39.01 vs. intercostal nerve 80.42 ± 24.9, p < 0.001). Our findings support using a branch of the radial nerve for the triceps muscle as a donor for axillary nerve reconstruction when possible. Intercostal nerves can be used in cases of total brachial plexus injury or involvement of the C7 root or posterior fascicle. Other promising methods need to be studied more thoroughly in order to validate and compare their results with the more commonly used methods.

Double Fascicular Transfer Using Partially Injured Donor Nerves: Is It Powerful Enough to Restore Elbow Flexion in Acute Brachial Plexus Injuries?

BACKGROUND

 Loss of elbow flexion is a common sequela of acute brachial plexus injuries (BPIs). The Mackinnon/Oberlin-II double fascicular transfer (DFT) is a widely used method to restore this function in acute C5-6 or C5-7 injuries. This study attempted to evaluate if this technique can be applied reliably for cases involving C8 and/or T1 injuries.

METHODS

 Adult patients with acute BPIs who underwent the Mackinnon/Oberlin-II DFT in our center between 2008 and 2018 were retrospectively identified. Group I (n = 37) included patients with only C5-6 or C5-7 injury, while group II (n = 32) patients presented C5-8 ± T1 injuries. The demographic data, pre- and postoperative neurologic evaluations, electrodiagnostic studies, and grip strength assessment were collected.

RESULTS

 A total of 69 patients met the inclusion criteria. Preoperatively, the patients in group II presented poorer nerve conduction and electromyography in both the median and the ulnar nerves and the supply muscles. The percentage of M3 achievement in both groups was 91.9 versus 87.5% and M4 was 73.0 and 71.9%, respectively, which both were not statically significant but the achievement of group II was slower than the group I, 1 to 2 months slower, respectively. Both groups had 57.57 and 46.0% of the postoperative grip power compared with the healthy side, the result of shoulder abduction was not different (p = 0.480).

CONCLUSION

 With careful preoperative evaluation, early intervention, appropriate intraoperative functional fascicle selection, and aggressive postoperative rehabilitation, indications for the Mackinnon/Oberlin-II DFT technique can safely include acute C5-8 injuries and even partial T1 acute BPIs.

[Nerve transposition (nerve transfer): development and principles]

This review article presents the history, indications and techniques for the usual nerve transpositions in the upper extremities. By means of nerve transposition paralyzed muscles are reinnervated using dispensable donor motor axons. Many standard operations on the upper extremities are attributable to concepts of German-speaking surgeons and orthopedists. The reliable return of function by the short-range and selective motor reinnervation using nerve transfer results in a renaissance of these techniques. The spectrum of applications has been substantially extended in recent years. In order to achieve an optimal result, a subtle microsurgical technique is necessary. In this way excellent results can be achieved even for complex proximal nerve injuries.

Defining the Reliability of Deltoid Reanimation by Nerve Transfer When Using Abnormal but Variably Recovered Triceps Donor Nerves

Upper brachial plexus injuries to the C5/6 roots or axillary nerve can result in severe deficits in upper limb function. Current techniques to reinnervate the deltoid muscle utilise the well-described transfer of radial nerve branches to triceps to the axillary nerve. However, in around 25% of patients, there is a failure of sufficient deltoid reinnervation. It is unclear in the literature if deltoid reanimation should be attempted with a nerve transfer from a weak but functioning triceps nerve. The authors present the largest series of triceps to axillary nerve transfers for deltoid reanimation in order to answer this clinical question. Seventy-seven consecutive patients of a single surgeon were stratified and analysed in four groups: (1) normal triceps at presentation, (2) abnormal triceps at presentation recovering to clinically normal function preoperatively, (3) abnormal triceps at presentation remaining abnormal preoperatively, and lastly (4) where pre-operative triceps function was deemed insufficient for use, requiring alternative reconstruction for deltoid reanimation. The authors considered deltoid re-animation of ≥ M4 as successful for the purpose of this study. Median Medical Research Council (MRC) values demonstrate group 1 achieves this successfully (M5), while median values for groups 2–4 result in M4 power (albeit with decreasing interquartile ranges). Median post-operative shoulder abduction active range of motion (AROM) values were represented by 170° (85–180) in group 1, 117.5° (97.5–140) in group 2, 90° (35–150) in group 3, and 60° (40–155) in group 4. For both post-operative assessments, subgroup analyses demonstrated statistically significant differences when comparing group 1 with groups 3 and 4 (p < 0.05), while all the other group to group pairwise comparisons did not reach significance. The authors postulated that triceps deficiency can act as a surrogate marker of a more extensive plexus injury and may predict poorer outcomes if the weakness persists representing the trending differences between groups 2 and 3. However, given no statistical differences were demonstrated between groups 3 and 4, the authors conclude that utilising an abnormal triceps nerve that demonstrates sufficient strength and redundancy intraoperatively is preferable to alternative transfers for deltoid reanimation. Lastly, in group 4 patients where triceps nerves are damaged and unusable for nerve transfer, alternative operations can also achieve sufficient outcomes and should be considered for restoration of shoulder abduction.

Brain changes after peripheral nerve repair: limitations of neuroplasticity

Neuroplasticity is the capacity of the central nervous system to adapt to external or internal stimuli. It is being increasingly recognized as an important factor which contributes to the successful outcome of nerve transfers. Other much more well-known factors are the number of axons that cross the coaptation site, the interval between trauma and repair, and age. Neuroplasticity is mediated by synaptic and neurotransmitter changes which underlie activation of previously existing but low-active connections in the brain. Dendritic sprouting and axonal elongation might also take place, but is likely less prominent. We review different factors that play a role in neuroplasticity and functional regeneration after specific nerve transfers. These factors include, amongst others, the distance between cortical areas of the donor and receptor neurons; the presence versus absence of pre-existing low-active inter-neuronal connections; gross versus fine movement restoration; rehabilitation; brain trauma and also very important: the age. The potential for plastic adaptation should be taken into consideration if the surgical strategy and post-operative rehabilitation are planned, as its influence on results cannot be denied.

Comparison between long and lower medial head triceps branches in dual neurotization for shoulder function restoration in upper brachial plexus palsy

PURPOSE

In upper brachial plexus injury (UBPI), restoring shoulder function is crucial. This study compares the transfer of long and lower medial heads of triceps branches to the axillary nerve to achieve proper restoration of function.

PATIENTS AND METHODS

A retrospective comparative study was conducted between two groups of patients with (UBPI). Group I patients (10) [mean age: 19 ± 10.6 years] were managed by transferring triceps long head branch to axillary nerve while group II patients (8) [mean age: 26 ± 9.6 years] were managed by triceps lower medial head branch transfer. The mean time from injury to surgery was 6 ± 1.3 and 5 ± 1.7 months respectively. All patients were followed up for a minimum of 12 months with the assessment of VAS, DASH score, active range of motion (AROM) and strength of shoulder abduction and external rotation; in addition to shoulder endurance and strengths of donors. Postoperative, three-monthly, electrodiagnostic assessments were performed.

RESULTS

Postoperatively, the mean VAS and DASH scores; in addition to endurance time, showed significant enhancement in both groups. Patients in both groups have accomplished a mean abduction (AROM) of 98° ± 27.9 and 97° ± 11.9 respectively. The mean external rotation (AROM) was 48° ± 18.4 and 47° ± 9.2 respectively. Furthermore, group II patients had less triceps morbidity in addition to earlier and enhanced electrophysiological recovery.

CONCLUSIONS

Dual neurotization for shoulder function restoration in (UBPI) is capable of providing proper functional results with minimal donor morbidity. The triceps lower medial branch provides an excelling donor due to less triceps morbidity, extra length; yet, earlier and enhanced electrophysiological recovery.

Nerve transfers in the upper extremity: A review

Injury of the brachial plexus and peripheral nerve often result in significant upper extremity dysfunction and disability. Nerve transfers are replacing other techniques as the gold standard for brachial plexus and other proximal peripheral nerve injuries. These transfers require an intimate knowledge of nerve topography, a technically demanding Intraneural dissection and require extensive physical therapy for retraining. In this review, we present a summary of the most widely accepted nerve transfers in the upper extremity described in the current literature.

Anatomy of the nerves to the teres minor and the long head of the triceps brachii for electromyography

BACKGROUND

We investigated the branching pattern and topographic anatomy of the nerves to the teres minor (Tm) and the long head of the triceps brachii (LHT) in relation to reference lines extending between surface landmarks, to identify the innervation patterns of, and the optimal needle placement points within, the Tm and the LHT.

METHODS

The anatomical courses of the nerves to the Tm and the LHT were investigated in 37 upper limbs of fresh-frozen cadavers. Distances from the acromion to nerve penetration points, and crossing points of reference lines with the Tm and LHT were measured in 27 cadaveric upper limbs.

RESULTS

The Tm was innervated by the axillary nerve in all specimens in three patterns, and the LHT was innervated exclusively by the radial nerve. Our dissection and measurements indicate that the midpoint of the reference line from the acromion to the inferior angle of the scapula is the optimal needle insertion point for the Tm. The target point for the LHT appears to be the one-third point of the reference line from the acromion to the medial epicondyle, or the two-thirds point of the reference line from the acromion to the axillary fold.

CONCLUSIONS

We investigated the branching pattern of the nerves to the Tm and the LHT and propose optimal needle placement points for electromyography of the Tm and LHT.

Nerve graft versus nerve transfer for neonatal brachial plexus: shoulder outcomes

OBJECTIVE

The decision-making in neonatal brachial plexus palsy (NBPP) treatment continues to have many areas in need of clarification. Graft repair was the gold standard until the introduction of nerve transfer strategies. Currently, there is conflicting evidence regarding outcomes in patients with nerve grafts versus nerve transfers in relation to shoulder function. The objective of this study was to further define the outcomes for reconstruction strategies in NBPP with a specific focus on the shoulder.

METHODS

A cohort of patients with NBPP and surgical repairs from a single center were reviewed. Demographic and standard clinical data, including imaging and electrodiagnostics, were gathered from a clinical database. Clinical data from physical therapy evaluations, including active and passive range of motion, were examined. Statistical analysis was performed on the available data.

RESULTS

Forty-five patients met the inclusion criteria for this study, 19 with graft repair and 26 with nerve transfers. There were no significant differences in demographics between the two groups. Understandably, there were no patients in the nerve grafting group with preganglionic lesions, resulting in a difference in lesion type between the cohorts. There were no differences in preoperative shoulder function between the cohorts. Both groups reached statistically significant improvements in shoulder flexion and shoulder abduction. The nerve transfer group experienced a significant improvement in shoulder external rotation, from -78° to -28° (p = 0.0001), whereas a significant difference was not reached in the graft group. When compared between groups, there appeared to be a trend favoring nerve transfer in shoulder external rotation, with the graft patients improving by 17° and the transfer patients improving by 49° (p = 0.07).

CONCLUSIONS

In NBPP, patients with shoulder weakness experience statistically significant improvements in shoulder flexion and abduction after graft repair or nerve transfer, and patients with nerve transfers additionally experience significant improvement in external rotation. With regard to shoulder external rotation, there appear to be some data supporting the use of nerve transfers.

Radial to Axillary Nerve Transfer Outcomes in Shoulder Abduction: A Systematic Review

Background

Brachial plexus and axillary nerve injuries often result in paralysis of the deltoid muscle. This can be functionally debilitating for patients and have a negative impact on their activities of daily living. In these settings, transferring the branch of the radial nerve innervating the triceps to the axillary nerve is a viable treatment option. Additional nerve transfers may be warranted. This study sought to determine the efficacy of nerve transfer procedures in the setting of brachial plexus and axillary nerve injuries and factors affecting clinical outcomes.

Methods

The U.S. National Library of Medicine's website "PubMed" was queried for "radial to axillary nerve transfer" and "brachial plexus nerve transfer." An initial review by two authors was performed to identify relevant articles followed by a third author validation utilizing inclusion and exclusion criteria. Individual patient outcomes were recorded and pooled for final analysis.

Results

Of the 80 patients, 66 (82.5%) had clinical improvement after surgical nerve transfer procedures. Significant difference in clinical improvement following nerve transfer procedures was correlated with patient age, mechanism of injury, brachial plexus vs isolated axillary nerve injuries, multiple nerve transfers vs single nerve transfers, and surgery within the first 7 months of injury. The branch of the radial nerve supplying the triceps long head showed improved clinical results compared with the branch of the radial nerve supplying the triceps medial head and anconeus.

Conclusion

Nerve transfers have been shown to be effective in restoring shoulder abduction in both isolated axillary nerve injuries and brachial plexus injuries.

Isolated Axillary Nerve Rupture due to Closed Nondislocating Injury of the Shoulder in Contact Sports: A Report of 2 Cases

CASE

Axillary nerve rupture without shoulder joint fracture or dislocation in contact sports is very rare. To date, there has been no detailed report on such cases. We present 2 rare cases of axillary nerve rupture in contact sports who were successfully treated with free nerve grafting.

CONCLUSION

In contact sports, the deltoid muscle is sometimes paralyzed temporarily after a collision. However, similar to our cases, the axillary nerve can be lacerated without fracture or dislocation. It is necessary to watch the course of paralysis carefully and consider nerve reconstruction if it does not recover.

Surgical reconstructions for adult brachial plexus injuries. Part I: Treatments for combined C5 and C6 injuries, with or without C7 injuries

Brachial plexus injuries will cause a significantly decreased quality of life. Patients with upper arm type brachial plexus injuries, which means C5 and C6 roots injury, will lose their shoulder elevation/abduction/external rotation, and elbow flexion function. Additional elbow, wrist, and hand extension function deficit will occur in patients with C7 root injury. With the advances of reconstructive procedures, the upper arm brachial plexus injuries can be successfully restored through nerve repair, nerve grafting, nerve transfer, muscle / tendon transfer and free functioning muscle transfer. In this review article, we summarized the various reconstructive procedures to restore the function of shoulder and elbow. Nowadays, the upper arm type BPI can be treat with satisfied outcomes (80-90% successful rate).

Transfers of the Ipsilateral C7 Plus the Spinal Accessory Nerve Versus Triple Nerve Transfers for Treatment of C5-C6 Avulsion of the Brachial Plexus

PURPOSE

To compare the long-term results of transfers of the ipsilateral C7 (IC7) plus spinal accessory nerve (SAN) with those of triple nerve transfers (TNT) using one fascicle of the ulnar nerve to the biceps motor branch (Oberlin's procedure), SAN transferred to the suprascapular nerve, and transfer of the long head of triceps nerve branch to the anterior branch of axillary nerve to treat C5-C6 avulsion of the brachial plexus.

METHODS

The IC7 group included 9 patients undergoing transfers of IC7 to the upper trunk and SAN to the suprascapular nerve. Median age at surgery was 26 years and interval between injury and surgery was 2.8 months. Patients were observed for a median of 118 months. The TNT group contained 13 patients, median age 33 years; interval between injury and surgery was 3.1 months. Patients were observed for a median of 103 months.

RESULTS

In the IC7 group, median shoulder abduction was 105° and median external rotation of the shoulder was 64°, which was similar to that of the TNT group (89° abduction and 58° external rotation). Eight of nine patients recovered at least M3 (Modified Narakas scale) strength of deltoid in the IC7 group, which was similar to that in the TNT group (11 of 13 patients). Six of nine patients achieved at least Medical Research Council grade 3 (MRC3) strength of biceps in the IC7 group, which was similar to that in the TNT group (11 of 13 patients). Of 4 patients in the IC7 group with a preoperative latissimus dorsi strength of MRC3 or less, 3 gained a deltoid strength of M3 or less, and 3 a biceps strength of MRC2 or less.

CONCLUSIONS

Transfers of IC7 plus SAN provide results comparable to those of TNT for treatment of C5-C6 avulsion.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Contralateral C7 transfer to axillary and median nerves in rats with total brachial plexus avulsion

Background

Contralateral cervical 7 nerve (cC7) was used to repair two recipient nerves simultaneously for patients with total brachial plexus avulsion (TBPA).

Objective

To evaluate the effect of cC7 transfer to axillary and median nerves in rats with TBPA.

Methods

Eighty S-D rats were divided into 4 groups randomly on average. Group A: cC7-median nerve, Group B: cC7-axillary nerve, Group C: cC7-median and axillary nerves, Group D: TBPA without repair. The evaluation tools included behavioral tests, electromyogram (EMG), measurement of cross-sectional area of muscle fiber, nerve fiber count and gene expression assay.

Results

The effective rates of EMG were 90 and 70% in Flexor Carpi Radialis (FCR) in Group A and C, while 70 and 60% in deltoid (DEL) in Group B and C, respectively. In behavioral test, the differences of effective rates between groups were not significant. The mean cross-sectional area of FCR in Group A or C was significantly larger than that in Group D. Either the number of median or axillary nerve fibers in Group A, B or C was statistically more than that in Group D. No matter for FCR or DEL, there were no significant differences in the ratios of relative expression of Muscle Atrophy F-box(MAFBOX)and Muscle RING Finger 1(MURF1)among these groups.

Conclusion

Compared with cC7 transfer to median nerve, cC7 transfer to both median and axillary nerves did not affect median nerve recovery. The deltoid muscle also could be restored. The recovery proportion of axillary nerve was less than that of median nerve.

Can a Partially Injured Donor Nerve Restore Elbow Flexion in an Acute Brachial Plexus Injury in Rats?

BACKGROUND

Loss of elbow flexion commonly occurs following acute brachial plexus injury. The double fascicular transfer is often used in acute C5-C6 and C5-C7 root injuries, but is rarely applied in cases involving concomitant C8 or T1 root injury. The authors designed a rat model using varying severities of lower trunk injury to determine whether partial injury to the lower trunk affects nerve transfers for elbow flexion.

METHODS

There were four different rat groups in which 0, 25, 75, or 100 percent of the donor lower trunk remained intact. One-fourth of the cross-sectional area of the ulnar nerve was then transferred to the musculocutaneous nerve immediately. The authors assessed outcomes using a grooming test, muscle mass, retrograde labeling of sensory/motor neurons that regenerated axons, and immunohistochemical stain of regenerated axons.

RESULTS

Five months after nerve transfer, rats that underwent partial injury of the lower trunk fared significantly worse than the rats in whom the donor lower trunk remained 100 percent intact, but significantly better than the rats with 0 percent intact lower trunk. Rats with 25 or 75 percent of the lower trunk intact recovered equivalent function, at both the donor and recipient sites.

CONCLUSIONS

Although relatively weak compared with the 100 percent intact donor lower trunk group, the partially injured donor nerve was still functional; even though the nerve sustained a partial injury, the residual axons reinnervated the target muscles. The power of the muscles following either 25 percent or 75 percent injuries was equal after the recovery. Resorting to this approach may be useful in cases in which no alternatives are available.

Evaluation of Triple Neurotization Technique as a Single Procedure in Adult Traumatic Brachial Plexus Injury

INTRODUCTION

Brachial plexus injuries are common and result in significant disabilities. This study evaluated the outcome of triple neurotization as a single procedure for upper trunk brachial plexus injury.

PATIENTS AND METHODS

Some 25 adult consecutive patients with injured upper trunk brachial plexus who underwent microscopic reconstructive surgery using triple neurotization technique in the authors' institute were recruited in this study. Data on operative and functional outcomes were captured. Modified Narkas scale was used to evaluate the shoulder function in addition to Waikakul scale which was used to evaluate the elbow function. Data were analyzed with respect to short and long term with a median follow-up duration of two years.

RESULTS

Assessment of the recovered shoulder abduction was excellent in 48% (n=12), good in 24% (n=6), fair in 16% (n=4), and poor in 12% of cases (n=3). Shoulder external rotation recovery was excellent in 48% (n=12), good in 12% (n=3), fair in 12% (n=3), and poor in 28% of cases (n=7). Recovery of elbow flexion was excellent in 60% (n=15), good in 12% (n=3), fair in 12% (n=3), and poor in 16% of cases (n=4). The mean value of recovered shoulder abduction was 111.26 degrees (range: 70-150). The mean value of restored shoulder external rotation was 57.5 degrees (range: 45-70). The mean value of restored elbow flexion was 75 degrees (range: 55-120).

CONCLUSION

Triple neurotization technique can be effective to restore elbow flexion, shoulder abduction, and external rotation in adult patients with upper trunk brachial plexus injury.

Upper Extremity Axon Counts and Clinical Implications for Motor Nerve Transfer

BACKGROUND

Nerve transfers are planned based on the following parameters: location, number of branches, and axon count matching of the donor and recipient nerves. The authors have previously defined the former two in upper limb muscles. In the literature, axon counts are obtained from various sources, using different methods of histomorphometry. This study describes the axon counts of the same primary motor nerve branches from the authors' previous study using a uniform method of manual histomorphometry and completes the authors' blueprint of upper limb neuromuscular anatomy for reconstructive surgery.

METHODS

The distal ends of the primary nerve branches of 23 upper limb muscles were harvested from 10 fresh frozen cadaveric upper limbs. Manual quantitative histomorphometry was performed by two independent investigators, and the average was reported.

RESULTS

The primary nerve branches of the arm muscles had higher average axon counts (range, 882 to 1835) compared with those of the forearm muscles (range, 267 to 883). In the forearm, wrist flexor (range, 659 to 746) and extensor (range, 543 to 745) nerve branches had axons counts that were similar to those of potential donors (e.g., supinator, n = 602; pronator teres, n = 625; flexor digitorum superficialis, n = 883; and flexor digitorum profundus, n = 832).

CONCLUSIONS

Apart from describing the axon counts of the upper limb, the authors have found that the forearm axon counts are very comparable. This insight, when combined with information on the location and number of primary nerve branches, will empower surgeons to tailor bespoke nerve transfers for every clinical situation.

Comparison of spinal accessory nerve transfer to supra-scapular nerve vs. shoulder arthrodesis in adults with brachial plexus injury

BACKGROUND

Restoring shoulder mobility, stability, and strength is a key goal in patients with brachial plexus injuries. Shoulder arthrodesis is chiefly used as an adjunct to, or after failure of, initial direct nerve surgery. The objective of this study was to compare clinical and functional shoulder outcomes after direct nerve transfer vs. shoulder arthrodesis in adults with supra-clavicular brachial plexus injuries.

HYPOTHESIS

Shoulder arthrodesis, currently used as a salvage procedure in brachial palsy injuries, deserves to be viewed to a valid alternative to direct nerve transfer.

MATERIAL AND METHODS

A retrospective study was conducted in 58 patients with a follow-up of at least 2 years. Among them, 20 were managed by transfer of a spinal accessory nerve fascicle to the supra-scapular nerve and 38 by shoulder arthrodesis. Outcome measures were shoulder range-of-motion, isometric shoulder strength, and the Disabilities of the Arm, Shoulder, and Hand (DASH) score.

RESULTS

Mean age at surgery was 24 years and mean follow-up was 46 months (range, 24-156 months). Motion ranges of the shoulder were not significantly different between the two treatment groups. Data variance was significantly greater in the nerve transfer group than in the shoulder arthrodesis group for scapular antepulsion (p=0.0011), abduction (p<0.001), and external rotation (p=0.0066). Strength was significantly greater in the arthrodesis group in all directions of motion. The DASH scores showed no significant between-group differences.

CONCLUSIONS

The results of this study conflict with the widely help opinion that nerve transfer to the supra-scapularis nerve produces better clinical outcomes compared to shoulder arthrodesis. Nerve transfer was not better than shoulder arthrodesis in our patients. The data variance heterogeneity suggests poor predictability and reliability of nerve transfer, in contrast to the modest but predictable and uniform results of shoulder arthrodesis.

LEVEL OF EVIDENCE

IV, retrospective observational comparative study.

Exploration of the axillary nerve through an open posterior endoscopic-assisted (OPEA) approach: First clinical experience

INTRODUCTION

Previous studies have described a segment of the axillary nerve (AN) that cannot be surgically explored through the deltopectoral and posterior surgical open approaches (blind zone). We present the first two cases using an endoscopic-assisted approach to explore the AN through a posterior approach.

MATERIAL AND METHODS

Two patients were evaluated, in whom clinical, electrodiagnostic testing, and MRI could not localize the level of the AN dysfunction. An open posterior endoscopic-assisted (OPEA) approach was performed 4 and 9 months after injury in an attempt to visualize all segments of the AN. Photographs and videos were taken to evaluate the intraoperative visualization of the AN and provide long-term clinical follow-up.

RESULTS

Almost the entire AN was visualized with the scope through the OPEA approach, avoiding the deltopectoral approach. No AN lesion was found during the nerve exploration. A triceps branch to AN transfer, using the previous posterior approach, was performed. Patients in both groups achieved a deltoid muscle function of BMRC grade 4 after 24 and 9 months, respectively.

CONCLUSION

The exploration of the AN through the OPEA approach was a useful strategy to visualize the blind zone of the AN without requiring the addition of a deltopectoral approach. We believe this novel technique has a role in selected cases of AN injury.

Anatomical Study of Innervation of the Supinator Muscle to Reinnervate the Posterior Interosseous Nerve

Objective  The purpose of this anatomical study was to analyze the possibility of transferring radial nerve branches to the supinator muscle to reinnervate the posterior interosseous nerve (PIN) originating from the C7–T1 roots.

Methods  Thirty members of 15 cadavers, all male, prepared with an intra-arterial glycerol and formaldehyde solution injection, were dissected.

Results  All dissected limbs presented at least one branch intended for the superficial and the deep heads of the supinator muscle. These branches originated from the PIN. A branch to the supinator muscle, proximal to the arcade of Frohse, was identified in six members. In addition, 2 and 3 branches to the supinator muscle were found in 11 and 4 members, respectively. In two limbs, only one branch detached from the PIN, but it duplicated itself proximal to the arcade of Frohse. Seven limbs had no branches to the supinator muscle at the region proximal to the arcade of Frohse. The branches destined for the supinator muscle were sectioned at the neuromuscular junction for connection with no tension to the PIN. The combined diameter of the branches for the supinator muscle corresponded, on average, to 53.5% of the PIN diameter.

Conclusion  The radial nerve branches intended for the supinator muscle can be transferred, with no tension, directly to the PIN to restore thumb and finger extension in patients with C7–T1 brachial plexus lesions.

Radial-to-Axillary Nerve Transfer Resolves Symptoms of Axillary Nerve Injury Due to Proximal Humerus Fracture-Dislocation in an Elderly Patient Treated With Hemiarthroplasty

Proximal humerus fractures in elderly patients are a common injury that can often be treated nonoperatively. However, surgery is indicated with some fracture patterns. Arthroplasty is an attractive option with poor bone quality, when there is a low likelihood of success with open reduction and internal fixation, and due to a timely return to function and weight bearing of the extremity in this patient population. A prerequisite for shoulder function for both native and replacement joints is a functional deltoid. Unfortunately, elderly patients with complex fracture patterns can sustain axillary nerve palsies that make management more difficult. The authors present a case of an elderly patient with a complex fracture-dislocation of the proximal humerus with traumatic axillary nerve palsy treated with hemiarthroplasty, followed by radial-to-axillary nerve transfer after the deltoid failed to improve. Congruency of the joint was restored and significant improvement in objective scoring metrics was achieved, making nerve transfer in this clinical scenario a viable option. [Orthopedics. 2019; 42(4):e395-e398.].

The Anterior Approach for Transfer of Radial Nerve Triceps Fascicles to the Axillary Nerve

Nerve transfers are an increasingly popular method for surgical treatment of nerve injuries. One of the most popular of these is the transfer of radial nerve triceps fascicles to the axillary nerve. The most common approach for this transfer is the posterior approach, which gives excellent access to both nerves but is not easy to combine with other nerve transfers. We describe here an alternative, the anterior approach, that offers safe access to both radial and axillary nerves and has the added advantage of compatibility with approaches for other common nerve transfers.

Nerve transfers for peripheral nerve injury in the upper limb: a case-based review

Nerve transfer has become a common and often effective reconstructive strategy for proximal and complex peripheral nerve injuries of the upper limb. This case-based discussion explores the principles and potential benefits of nerve transfer surgery and offers in-depth discussion of several established and valuable techniques including: motor transfer for elbow flexion after musculocutaneous nerve injury, deltoid reanimation for axillary nerve palsy, intrinsic re-innervation following proximal ulnar nerve repair, and critical sensory recovery despite non-reconstructable median nerve lesions.

Cadaveric Dissection of the Axillary Nerve: An Investigation of Extra-Muscular and Intra-Muscular Branching Patterns

BACKGROUND

Variations in the axillary nerve branching patterns have been reported. The aim of the study is to investigate the extra- and intra-muscular course of the axillary nerve and quantify the regional innervation of the deltoid.

METHODS

In fresh frozen specimens, the origin of the axillary nerve from the posterior cord of the brachial plexus and its extra- and intra-muscular course were identified. Muscle dimensions, branching patterns and the distance from the axillary nerve origin to major branches were measured. The weights of muscle segments supplied by major branches of the axillary nerve were recorded.

RESULTS

Twenty-three cadaveric dissections were completed. The axillary nerve bifurcated within the quadrangular space in all cases. The mean distance from the origin to bifurcation of the axillary nerve was 39 ± 13 mm; from axillary nerve bifurcation to the teres minor branch was 13 ± 6 mm; and from axillary nerve bifurcation to the middle branch of anterior division was 26 ± 11 mm. The nerve to teres minor and superior lateral brachial cutaneous nerve originated from the posterior division or common trunk in all cases. No fibrous raphe were identified separating anterior, middle and posterior deltoid segments. The anterior division of axillary nerve supplied 85 ± 4% of the deltoid muscle (by weight). The posterior division supplied 15 ± 4% of the deltoid muscle (by weight). The posterior deltoid was supplied by both anterior and posterior divisions in 91.3% of cases.

CONCLUSIONS

This study demonstrates a consistent branching pattern of the axillary nerve. The anterior division of the axillary nerve innervates all three deltoid segments in most instances (85% of the deltoid by weight). This study supports the concept of re-innervation of the anterior division alone in isolated axillary nerve injuries.

Surgical Implications of Innervation Pattern of the Triceps Muscle: A Cadaveric Study

The innervation pattern of triceps is complex and not fully comprehended. Anomalous innervations of triceps have been described by various authors. We have attempted to delineate the nerve supply of the triceps and documented the anomalous innervations of its different heads. The brachial plexus and its major branches (in the region of the axilla and arm) and triceps were dissected in 36 embalmed cadaver upper limbs. Long head received one branch from radial nerve in 31 (86%) specimens. Four (11%) specimens received two branches including one that had dual innervation from the radial and axillary nerves, and one (3%) specimen had exclusive innervation from a branch of the axillary nerve. Medial head received two branches arising from the radial nerve in 34 (94%) specimens. One (3%) specimen received three branches from the radial nerve whereas one (3%) had dual supply from the radial and ulnar nerves. Lateral head received multiple branches exclusively from the radial nerve, ranging from 2 to 5, in all (100%) specimens. Knowledge of the variations in innervation of the triceps would not only help the surgeon to avoid inadvertent injury to any of the nerve branches but also offers new options for nerve and free functional muscle transfers.

Spinal accessory nerve to triceps muscle transfer using long autologous nerve grafts for recovery of elbow extension in traumatic brachial plexus injuries

OBJECTIVE

Reconstructive options for brachial plexus lesions continue to expand and improve. The purpose of this study was to evaluate the prevalence and quality of restored elbow extension in patients with brachial plexus injuries who underwent transfer of the spinal accessory nerve to the motor branch of the radial nerve to the long head of the triceps muscle with an intervening autologous nerve graft and to identify patient and injury factors that influence functional triceps outcome.

METHODS

A total of 42 patients were included in this retrospective review. All patients underwent transfer of the spinal accessory nerve to the motor branch of the radial nerve to the long head of the triceps muscle as part of their reconstruction plan after brachial plexus injury. The primary outcome was elbow extension strength according to the modified Medical Research Council muscle grading scale, and signs of triceps muscle recovery were recorded using electromyography.

RESULTS

When evaluating the entire study population (follow-up range 12–45 months, mean 24.3 months), 52.4% of patients achieved meaningful recovery. More specifically, 45.2% reached Grade 0 or 1 recovery, 19.1% obtained Grade 2, and 35.7% improved to Grade 3 or better. The presence of a vascular injury impaired functional outcome. In the subgroup with a minimum follow-up of 20 months (n = 26), meaningful recovery was obtained by 69.5%. In this subgroup, 7.7% had no recovery (Grade 0), 19.2% had recovery to Grade 1, and 23.1% had recovery to Grade 2. Grade 3 or better was reached by 50% of patients, of whom 34.5% obtained Grade 4 elbow extension.

CONCLUSIONS

Transfer of the spinal accessory nerve to the radial nerve branch to the long head of the triceps muscle with an interposition nerve graft is an adequate option for restoration of elbow extension, despite the relatively long time required for reinnervation. The presence of vascular injury impairs functional recovery of the triceps muscle, and the use of shorter nerve grafts is recommended when and if possible.

An All-Anterior Approach for Quadruple Nerve Transfer for Upper Trunk Brachial Plexus Injuries

BACKGROUND

The most commonly performed nerve transfers in upper trunk (UT) or partial brachial plexus injuries (BPIs) include the spinal accessory nerve to suprascapular nerve, Oberlin, and, lately, radial nerve (RN) (branch to triceps) to axillary nerve (AN) transfers. Routinely, the former 3 procedures are performed through an anterior approach (supraclavicular plus infraclavicular), while the triceps branch of the RN-AN transfer has been performed through a posterior approach with the patient in either the prone or semilateral position, which requires a separate incision in the posterior arm. The aim of the present study was to report the outcomes for 4 cases of quadruple nerve transfers performed for UT BPI using an all-anterior approach.

METHODS

The functional outcomes of 4 consecutive cases of UT BPI treated using an all-anterior approach were analyzed in terms of improvement in motor power and range of motion at the shoulder and elbow joints.

RESULTS

The mean age was 27.5 years (range, 16-40). All had sustained injuries from road traffic accidents. The mean injury to surgery interval was 4.5 months (range, 3-6). Of the 4 patients, 2 each had pre- and postganglionic injuries. All 4 patients had 0 of M0 power in shoulder abduction and external rotation, and elbow flexion. At a mean follow-up of 28.6 months, the average shoulder abduction was 157°, with an average of 82° of external rotation. The mean elbow flexion was 104°.

CONCLUSIONS

This technique appears to be feasible, with good-to-excellent outcomes achieved without requiring a separate posterior arm incision for the RN-AN transfer.

Innervation of the Long Head of the Triceps Brachii in Humans-A Fresh Look

The triceps brachii muscle occupies the posterior compartment of the arm in humans and has three heads. The lateral and medial heads originate from the humerus and the long head arises from the infraglenoid tubercle of the scapula. All heads form a common tendon that inserts onto the olecranon and the deep antebrachial fascia on each side of it. Each head receives its own motor branch, which all are thought to originate from the radial nerve. However, several studies reported that the motor branch of the long head of the triceps (LHT) arises from the axillary nerve or the posterior cord. Here, we dissected 27 triceps in 15 cadavers to analyze the innervation of the LHT and found only radial innervation, which contradicts those studies. We examined studies reporting that the motor branch to the LHT in humans does not arise from the radial nerve as well as studies of the triceps in primates. Occasional variations of the innervation of skeletal muscles are normal, but a change of principal motor innervation from radial to axillary nerve has important implications. This is because the axillary nerve is often involved during shoulder injuries. The precise identification of the prevalence of axillary versus radial innervation is therefore clinically relevant for surgery, nerve drafting, and occupational and physical therapy. We conclude that the primary motor branch to the LHT arises from the radial nerve but axillary/posterior cord innervations occur occasionally. We suggest the development of a standard methodology for further studies. Anat Rec, 301:473-483, 2018. © 2018 Wiley Periodicals, Inc.

Salvage of cervical motor radiculopathy using peripheral nerve transfer reconstruction

Purpose: Motor nerve transfer surgery involves re-innervation of important distal muscles using either an expendable motor branch or a fascicle from an adjacent functioning nerve. This technique is established as part of the reconstructive algorithm for traumatic brachial plexus injuries. The reproducible outcomes of motor nerve transfer surgery have resulted in exploration of the application of this technique to other paralysing conditions. The objective of this study is to report feasibility and increase awareness about nerve transfer as a method of improving upper limb function in patients with cervical motor radiculopathy of different aetiology. Results: In this case series we report 3 cases with different modes of injury to the spinal nerve roots with significant and residual motor radiculopathy that have been successfully treated with nerve transfer surgery with good functional outcomes. The cases involved iatrogenic nerve root injury, tumour related root compression and degenerative root compression. Conclusion: Nerve transfer surgery may offer reliable reconstruction for paralysis when there has been no recovery following a period of conservative management. However the optimum timing of nerve transfer intervention is not yet identified for patients with motor radiculopathy.

Outcome of reverse shoulder arthroplasty with pedicled pectoralis transfer in patients with deltoid paralysis

BACKGROUND

Management of shoulder arthritis associated with deltoid paralysis can be very challenging. The purpose of this study was to report the outcome of reverse shoulder arthroplasty with pedicled pectoralis transfer to reconstruct the anterior deltoid in patients with symptomatic shoulder arthritis and a paralyzed deltoid.

METHODS

This study included 31 patients with an average age of 51 years (range, 27-73 years). All patients had chronic deltoid paralysis with significant loss of function due to progressive arthritis associated with rotator cuff deficiency. All patients underwent reverse shoulder arthroplasty with pedicled pectoralis muscle transfer. Additional transfers were performed in patients with no preoperative external rotation: 5 underwent latissimus transfer, and 3 underwent direct lower trapezius transfer to the infraspinatus.

RESULTS

At an average follow-up of 37 months, 29 patients had significant improvements in pain; the shoulder subjective value; the Disabilities of the Arm, Shoulder and Hand score; and shoulder range of motion, mainly flexion of 83° and external rotation of 15°. Two patients sustained postoperative acromial fractures and had persistent pain after surgery with minimal improvement in shoulder flexion and external rotation. One of them had a failed attempt at open reduction-internal fixation of the acromion.

CONCLUSION

Reverse shoulder arthroplasty with pedicled pectoralis transfer is a promising procedure that may lead to improved pain and function in patients with shoulder arthritis associated with deltoid paralysis.

Triceps motor branch transfer for isolated axillary nerve injury: Outcomes in 9 patients

INTRODUCTION

Triceps motor branch transfer has been used for more than ten years to restore deltoid function after axillary nerve injury. However, there have been few reports of the outcome of this procedure in isolated axillary nerve injury.

HYPOTHESIS

Triceps motor branch transfer could be an effective method to restore deltoid function for patients with isolated axillary nerve injury.

MATERIALS AND METHODS

Nine patients who underwent triceps motor branch transfer for treatment of isolated axillary nerve injury were followed up for at least 22 months. Shoulder abduction was assessed for all patients. The DASH outcome questionnaire was completed by every patient. Electrophysiological study was performed on 7 patients.

RESULTS

All patients regained≥90° (mean, 137°) shoulder abduction. Mean DASH score decreased from 35.2 before surgery to 13.1 at the last follow-up. There was no noticeable weakness of elbow extension in any patient.

DISCUSSION

Triceps motor branch transfer provided good results and may be a feasible alternative to nerve grafting for the treatment of complete isolated axillary nerve injury.

TYPE OF STUDY

IV, retrospective cohort study.

Axonal components of nerves innervating the human arm

OBJECTIVE

Axons traveling within the brachial plexus are responsible for the dexterous control of human arm and hand movements. Despite comprehensive knowledge on the topographical anatomy of nerves innervating the human upper limbs, the definite quantity of sensory and motor axons within this neural network remains elusive. Our aim was to perform a quantitative analysis of the axonal components of human upper limb nerves based on highly specific molecular features from spinal cord level to the terminal nerves at wrist level.

METHODS

Nerve specimen harvest at predefined harvesting sites (plexus roots and cords as well as major nerves originating from the brachial plexus innervating the arm and hand) was performed in 9 human heart-beating organ donors. Double immunofluorescence staining using antibodies against choline-acetyltransferase and neurofilament was performed to differentiate motor and sensory axons on nerve cross sections.

RESULTS

Three hundred fifty thousand axons emerge from the spinal cord to innervate the human upper limb, of which 10% are motor neurons. In all nerves studied, sensory axons outnumber motor axons by a ratio of at least 9:1. The sensory axon contribution increases when moving distally, whereas only 1,700 motor axons reach the hand to innervate the intrinsic musculature.

INTERPRETATION

Our results suggest that upper limb motor execution, and particularly dexterous coordination of hand movement, require an unexpectedly low number of motor neurons, with a large convergence of afferent input for feedback control. Ann Neurol 2017;82:396-408.

Restoration of shoulder abduction in brachial plexus avulsion injuries with double neurotization from the spinal accessory nerve: a report of 13 cases

In upper (C5-C7) and total (C5-T1) root avulsion brachial plexus injury, a method of double neurotization from a single donor spinal accessory nerve to two target nerves (suprascapular nerve and axillary nerve) may be done, leaving donor nerves available for reconstruction procedures to restore other aspects of upper limb function. A mean range of shoulder abduction of 91° (SD 25°) was achieved through this procedure in our study of 13 cases, of which seven cases were C5-C7 root avulsion and six cases were C5-T1 root avulsion brachial plexus injuries. Six of the former group and three of the latter group achieved >90° shoulder abduction. The technique of double neurotization from a single donor nerve provides favourable results in restoring shoulder abduction in avulsion brachial plexus injuries.

LEVEL OF EVIDENCE

IV.