Axillary nerve neurotization with the anterior deltopectoral approach in brachial plexus injuries

Distal Nerve Transfers in Hand and Forearm for Traumatic Brachial Plexus and Peripheral Nerve Injuries: A Narrative Review

Background

Various studies published good outcomes in brachial plexus injuries using nerve transfers for shoulder and elbow functions. However, little is known about the outcome of the distal nerve transfers in the forearm and hand. Targeting the nerve distally produces an early return of function in brachial plexus and peripheral nerve injuries (BPPNI). Therefore, researchers have focused on nerve transfers from the motor branches of the ulnar, median, and radial nerve. Similarly, sensory reinnervation is also obtained by potential donor transfers in the forearm and hand. There have been various attempts by surgeons to target the muscle and promote early reinnervation by different nerve transfers.

Conclusions

The distal nerve transfers in the forearm and hand are promising when performed early. It effectively restores hand and forearm functions and may be considered a better option than tendon transfer, which has a one-tendon-one function. This narrative review article discusses the different distal nerve transfers for various presentations of BPNNI.

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.

Is there any difference between anterior and posterior approach for the spinal accessory to suprascapular nerve transfer? A systematic review and meta-analysis

Dual nerve transfer of the spinal accessory nerve to the suprascapular nerve (SAN-SSN) and the radial nerve to the axillary nerve is considered to be the most feasible method of restoration of shoulder abduction in brachial plexus injuries. Supraspinatus muscle plays an important role in the initiation of abduction and its functional restoration is crucial for shoulder movements. There are two possible approaches for the SAN-SSN transfer: the more conventional anterior approach and the posterior approach in the area of scapular spine, which allows more distal neurotization. Although the dual nerve transfer is a widely used method, it is unclear which approach for the SAN-SSN transfer results in better outcomes. We conducted a search of English literature from January 2001 to December 2021 using the PRISMA guidelines. Twelve studies with a total 142 patients met our inclusion criteria. Patients were divided into two groups depending on the approach used: Group A included patients who underwent the anterior approach, and Group B included patients who underwent the posterior approach. Abduction strength using the Medical Research Scale (MRC) and range of motion (ROM) were assessed. The average MRC grade was 3.57 ± 1.08 in Group A and 4.0 ± 0.65 (p = 0.65) in Group B. The average ROM was 114.6 ± 36.7 degrees in Group A and 103.4 ± 37.2 degrees in Group B (p = 0.247). In conclusion, we did not find statistically significant differences between SAN-SSN transfers performed from the anterior or posterior approach in patients undergoing dual neurotization technique for restoration of shoulder abduction.

(-)-Epigallocatechin Gallate Attenuates Spinal Motoneuron Death Induced by Brachial Plexus Root Avulsion in Rats

Background:

Recent studies have indicated that epigallocatechin gallate (EGCG) benefits a variety of neurological insults. This study was performed to investigate the neuroprotective effect of EGCG after brachial plexus root avulsion in SD rats.

Methods:

One hundred twenty SD rats were randomized into the following three groups: an EGCG group, an Avulsion group, and a Sham group. There were 40 rats in each group. EGCG (100 mg/kg, i.p.) or normal saline was administered to rats immediately following the injuries. The treatment was continued from day 1 to day 7, and the animals were sacrificed on days 3, 7, 14 and 28 post-surgery for the harvesting of spinal cord samples for Nissl staining, immunohistochemistry (caspase-3, p-JNK, p-c-Jun) and western blot analysis (p-JNK, JNK, p-c-Jun, c-Jun).

Results:

EGCG treatment caused significant increases in the percentage of surviving motoneurons at days 14 and 28 (P<0.05) compared to the control animals. At days 3 and 7 after avulsion, the numbers of caspase-3-positive motoneurons in the EGCG-treated animals were significantly fewer than in the control animals (P<0.05). The numbers of p-JNK-positive motoneurons and the ratio of p-JNK/JNK were no significant differences between the Avulsion group and the EGCG-treated group after injury at any time point. The numbers of p-c-Jun-positive motoneurons and the ratio of p-c-Jun/c-Jun were significantly lower in EGCG-treated group compared with the Avulsion group at 3d and 7d after injury (p<0.05).

Conclusions:

Our results indicated that motoneurons were protected by EGCG against the cell death induced by brachial plexus root avulsion, and this effect was correlated with inhibiting c-Jun phosphorylation.

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.

Clinical outcomes report in different brachial plexus injury surgeries: a systematic review

Brachial plexus injury is a lesion that results in loss of function of the arm, and there are multiple ways of surgically approaching its treatment. Controlled trials that compare all surgical repair strategies and their clinical outcomes have not been performed. A systematic review was conducted to identify all articles that reported clinical outcomes in different surgeries (nerve transfer, nerve graft, neurolysis, end-to-end, multiple interventions, and others). Advanced search in PubMed was performed using the Mesh terms "brachial plexus injury" as the main topic and "surgery" as a subtopic, obtaining a total of 2153 articles. The clinical data for eligibility extraction was focused on collecting motor, sensory, pain, and functional recovery. A statistical analysis was performed to find the superior surgical techniques in terms of motor recovery, through the assessment of heterogeneity between groups, and of relationships between surgery and motor recovery. The frequency and the manner in which clinical outcomes are recording were described. The differences that correspond to the demographics and procedural factors were not statistically significant among groups (p > 0.05). Neurolysis showed the highest proportion of motor recovery (85.18%), with significant results between preoperative and post-operative motor assessment (p = 0.028). The proportion of motor recovery in each group according to the surgical approach differed significantly (X² = 82.495, p = 0.0001). The motor outcome was the most reported clinical outcome (97.56%), whereas the other clinical outcomes were reported in less than 15% of the included articles. Unexpectedly, neurolysis, a technique displaced by new surgical alternatives such as nerve transfer/graft, demonstrated the highest proportion of motor recovery. Clinical outcomes such as pain, sensory, and functional recovery were infrequently reported. These results introduce the need to re-evaluate neurolysis through comparative clinical trials, as well as to standardize the way in which clinical outcomes are reported.

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.

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.

Transfer of the musculocutaneous nerve branch to the brachialis muscle to the triceps for elbow extension: anatomical study and report of five cases

We report the study of the anatomical feasibility of transferring the nerve to the brachialis muscle to the upper medial head motor branch that innervate the triceps, and outcomes of such transfers in restoring elbow extension in five patients with posterior cord lesion of the brachial plexus. The length of the branches to the brachialis muscle measured 7.6 cm and the triceps upper medial head motor branch was 5 cm in 10 adult cadavers. Five male patients were treated with this transfer 5 months after the injury (range 4 to 6 months) after posterior cord injury of the brachial plexus with a mean follow-up of 31 months (range 28 to 36 months). Elbow extension scored M4 in all cases. No complications occurred. These preliminary results suggest that transferring the nerve to the brachialis muscle is an effective technique for the reconstruction of elbow extension after posterior cord brachial plexus injuries.

LEVEL OF EVIDENCE

IV.

Nerve Transfers to Restore Shoulder Function

The restoration of shoulder function after brachial plexus injury represents a significant challenge facing the peripheral nerve surgeons. This is owing to a combination of the complex biomechanics of the shoulder girdle, the multitude of muscles and nerves that could be potentially injured, and a limited number of donor options. In general, nerve transfer is favored over tendon transfer, because the biomechanics of the musculotendinous units are not altered. This article summarizes the surgical techniques and clinical results of nerve transfers for restoration of shoulder function.

Erythropoietin Attenuates the Apoptosis of Adult Neurons After Brachial Plexus Root Avulsion by Downregulating JNK Phosphorylation and c-Jun Expression and Inhibiting c-PARP Cleavage

In the present study, the effects of erythropoietin (EPO) on preventing adult neurons from apoptosis (introduced by brachial plexus avulsion) were examined, and the mechanism was analyzed. Fifty injury rat models were established in this study by using micro-hemostat forceps to pull out brachial plexus root from the intervertebral foramen in supine position. These models were divided into EPO group (avulsion + 1000 U/kg subcutaneously on alternate days) and control group (avulsion + normal saline). C5-T1 spinal cord was harvested at days 1, 2, 4, 7, and 14. Compared with the control group, the apoptosis of spinal motoneurons was significantly decreased on days 4 and 7 in the EPO group, which was also approved by TUNEL examination results. The detection of p-JNK and expression of c-Jun and cleavage of cleaved PARP (c-PARP) were also examined by immunohistochemistry and were increased immediately at day 1, and peaked at day 2, day 2, and day 4 in control group, respectively. However, the amounts were decreased and delayed by EPO treatment significantly at the same time points. In conclusion, the apoptosis of adult spinal motorneurons was associated with JNK phosphorylation, c-Jun expression, and caspase activity, and EPO-mediated neuronal protective effect is proved by downregulating the JNK phosphorylation and c-Jun expression and inhibiting of c-PARP cleavage.

Radial to axillary nerve neurotization for brachial plexus injury in children: a combined case series

OBJECT

Axillary nerve palsy, isolated or as part of a more complex brachial plexus injury, can have profound effects on upper-extremity function. Radial to axillary nerve neurotization is a useful technique for regaining shoulder abduction with little compromise of other neurological function. A combined experience of this procedure used in children is reviewed.

METHODS

A retrospective review of the authors' experience across 3 tertiary care centers with brachial plexus and peripheral nerve injury in children (younger than 18 years) revealed 7 cases involving patients with axillary nerve injury as part of an overall brachial plexus injury with persistent shoulder abduction deficits. Two surgical approaches to the region were used.

RESULTS

Four infants (ages 0.6, 0.8, 0.8, and 0.6 years) and 3 older children (ages 8, 15, and 17 years) underwent surgical intervention. No patient had significant shoulder abduction past 15° preoperatively. In 3 cases, additional neurotization was performed in conjunction with the procedure of interest. Two surgical approaches were used: posterior and transaxillary. All patients displayed improvement in shoulder abduction. All were able to activate their deltoid muscle to raise their arm against gravity and 4 of 7 were able to abduct against resistance. The median duration of follow-up was 15 months (range 8 months to 5.9 years).

CONCLUSIONS

Radial to axillary nerve neurotization improved shoulder abduction in this series of patients treated at 3 institutions. While rarely used in children, this neurotization procedure is an excellent option to restore deltoid function in children with brachial plexus injury due to birth or accidental trauma.

Outcome of contralateral C7 transfer to two recipient nerves in 22 patients with the total brachial plexus avulsion injury

The treatment of total brachial plexus avulsion injury is difficult with unfavorable prognosis. This report presents our experience on the contralateral C7 (CC7) nerve root transfer to neurotize two recipient nerves in the patients with total BPAI. Twenty-two patients underwent CC7 transfer to two target nerves in the injured upper limb. The patients' ages ranged from 13 to 48 years. The entire CC7 was transferred to pedicled ulnar nerve in the first stage. The interval between trauma and surgery ranged from 1 to 13 months. The ulnar nerve was transferred to recipients (median nerve and biceps branch or median nerve and triceps branch) at 2-13 months after first operation. The motor recovery of wrist and finger flexor to M3 or greater was achieved in 68.2% of patients, the sensory recovery of median nerve area recovered to S3 or greater in 45.5% of patients. The functional recovery of elbow flexor to M3 or greater was achieved in 66.7% of patients with repair of biceps branch and 20% of patients with repair of the triceps branch (P < 0.05). There were no statistical differences in median nerve function recovery at comparisons of the age younger and older than 20-years-old and the intervals between trauma and surgery. In conclusion, the use of CC7 transfer for repair two recipient nerves might be an option for treatment of total BPAI. The functional recovery of the repaired biceps branch appeared to be better than that of the triceps branch.

Valproic acid protection against the brachial plexus root avulsion-induced death of motoneurons in rats

In this study, the role of valproic acid (VPA) in protecting motoneuron after brachial plexus root avulsion was investigated in adult rats. Sixty rats were used in this study, and underwent the brachial plexus root avulsion injury, which was created by using a micro-hemostat forceps to pull out brachial plexus root from the intervertebral foramen. The animals were divided into two groups, VPA group administered with VPA dissolved in drinking water (300 mg/kg) daily, and control group had drinking water every day. The spinal cords (C5-T1) were harvested at day 1, 2, 3, 7, 14, and 28 for immunohistochemistry analysis, TUNEL staining, Nissl staining, and electron microscopy, respectively. The results showed that with VPA administration, the survival of motoneurons was promoted and the cell apoptosis was inhibited. The number of c-Jun and Bcl-2 positive motoneurons was increased immediately after avulsion both in control and VPA group, however, the percent of c-Jun positive motoneurons was decreased and the percent of Bcl-2 positive motoneurons was increased by VPA treatment significantly. Our results indicated that motoneurons were protected by VPA against cell death induced by brachial plexus root avulsion through c-Jun inhibition and Bcl-2 induction.

Feasibility of an endoscopic approach to the axillary nerve and the nerve to the long head of the triceps brachii with the help of the Da Vinci Robot

Surgery to transfer the axillary nerve and the nerve of the long head of the triceps presents two obstacles: 1) the access portals are not standardized and 2) the nerves are for their larger part approached through large incisions. The goal of this study was to explore the feasibility of an endoscopic microsurgical approach. The posterior aspect of a cadaver shoulder was approached through three communicating mini-incisions. The Da Vinci robot camera was installed on a central trocart, and the instrument arms on the adjacent trocarts. A gas insufflation distended the soft tissues up to the lateral axillary space. The branches of the axillary nerve and the nerve to the long head of the triceps brachii muscle were identified. The dissection of the axillary nerve trunk and its branches was easy. The posterior humeral circumflex veins and artery were dissected as well without any difficulty. Finding the nerve to the long head of the triceps brachii was found to be more challenging because of its deeper location. Robots properties allow performing conventional microsurgery: elimination of the physiologic tremor and multiplication of the movements. They also facilitate the endoscopic approach of the peripheral nerves, as seen in our results on the terminal branches of the axillary nerve and the nerve to the long head of the triceps brachii.