Transfer of brachialis branch of musculocutaneous nerve for finger flexion: Anatomic study and case report

Surgical Strategies for Functional Upper Extremity Reconstruction After Spinal Cord Injury

Spinal cord injuries (SCI) can substantially affect independence and quality of life, particularly by limiting upper extremity function. Surgical reconstruction offers the potential to restore motion in the hand, wrist, and elbow for those with deficits following cervical spinal cord injury. Techniques such as tendon transfer, tenodesis, and arthrodesis-often used in combination-are well-established strategies for enhancing upper extremity function. Nerve transfers have more recently been employed and differ from other procedures in that they are often time sensitive and should be performed before permanent muscle atrophy occurs. A comprehensive preoperative evaluation, including clinical examination and electrodiagnostic assessment, is essential to determine the availability and strength of donor tendons and nerves. The International Classification of Surgery for the Hand in Tetraplegia (ICSHT) system is the most utilized surgical classification for determining muscle that can be used for reconstruction. Based on this classification, prioritization is given to restoring elbow extension, wrist extension, pinch, and grasp. Postoperative rehabilitative therapy balances the need for immobilization while preventing joint stiffness and may also incorporate cortical retraining strategies to activate tendon and nerve transfers. Ultimately, a collaborative, interdisciplinary approach is essential for assessing the injury, determining operative candidacy, selecting the optimal treatment strategy, and providing tailored rehabilitation. This article explores the classification of SCI as it pertains to the upper limb, provides an overview of surgical options, describes the preoperative clinical and electrodiagnostic evaluation process, and discusses reconstructive strategies aimed at improving functional outcomes in individuals with SCI.

Brachialis to Anterior Interosseous Nerve Transfer: Comprehensive Anatomic Rationale

BACKGROUND AND OBJECTIVES

Distal nerve transfers for muscle reinnervation and restoration of function after upper and lower motor neuron lesions are a well-established surgical approach. The brachialis to anterior interosseous nerve (BrAIN) transfer is performed for prehension reanimation in lower brachial plexus and traumatic cervical spinal cord injuries. The aim of the study is to shed light on the inconsistent results observed in patients who undergo the BrAIN transfer.

METHODS

An anatomic dissection was conducted on 30 fresh upper limb specimens to examine the intraneural topography of the median nerve (MN) in the upper arm at the level of the BrAIN transfer and the presence of intraneural fascicular interconnections distally.

RESULTS

Fascicular interconnections between the AIN and other MN branches were consistently found in the distal third of the upper arm. The first interconnection was at 3.85 ± 1.82 cm proximal to the interepicondylar line, and the second one, after further proximal neurolysis, was at 9.45 ± 1.16 cm from the interepicondylar line. Intraneural topography of the AIN at the transfer level varied, with dorsomedial, dorsolateral, and purely dorsal locations observed.

CONCLUSION

Consistent fascicular interconnections between the AIN and MN branches and intraneural topography variability of the MN may lead to aberrant reinnervation.

Distal nerve transfers for peripheral nerve injuries: indications and outcomes

Distal nerve transfer is a refined surgical technique involving the redirection of healthy sacrificable nerves from one part of the body to reinstate function in another area afflicted by paralysis or injury. This approach is particularly valuable when the original nerves are extensively damaged and standard repair methods, such as direct suturing or grafting, may be insufficient. As the nerve coaptation is close to the recipient muscles or skin, distal nerve transfers reduce the time to reinnervation. The harvesting of nerves for transfer should usually result in minimal or no donor morbidity, as any anticipated loss of function is compensated for by adjacent muscles or overlapping cutaneous territory. Recent years have witnessed notable progress in nerve transfer procedures, markedly enhancing the outcomes of upper limb reconstruction for conditions encompassing peripheral nerve, brachial plexus and spinal cord injuries.

Peripheral nerve transfers for dysfunctions in central nervous system injuries: a systematic review

BACKGROUND

The review highlights recent advancements and innovative uses of nerve transfer surgery in treating dysfunctions caused by central nervous system (CNS) injuries, with a particular focus on spinal cord injury (SCI), stroke, traumatic brain injury, and cerebral palsy.

METHODS

A comprehensive literature search was conducted regarding nerve transfer for restoring sensorimotor functions and bladder control following injuries of spinal cord and brain, across PubMed and Web of Science from January 1920 to May 2023. Two independent reviewers undertook article selection, data extraction, and risk of bias assessment with several appraisal tools, including the Cochrane Risk of Bias Tool, the JBI Critical Appraisal Checklist, and SYRCLE's ROB tool. The study protocol has been registered and reported following PRISMA and AMSTAR guidelines.

RESULTS

Nine hundred six articles were retrieved, of which 35 studies were included (20 on SCI and 15 on brain injury), with 371 participants included in the surgery group and 192 in the control group. These articles were mostly low-risk, with methodological concerns in study types, highlighting the complexity and diversity. For SCI, the strength of target muscle increased by 3.13 of Medical Research Council grade, and the residual urine volume reduced by more than 100 ml in 15 of 20 patients. For unilateral brain injury, the Fugl-Myer motor assessment (FMA) improved 15.14-26 score in upper extremity compared to 2.35-26 in the control group. The overall reduction in Modified Ashworth score was 0.76-2 compared to 0-1 in the control group. Range of motion (ROM) increased 18.4-80° in elbow, 20.4-110° in wrist and 18.8-130° in forearm, while ROM changed -4.03°-20° in elbow, -2.08°-10° in wrist, -2.26°-20° in forearm in the control group. The improvement of FMA in lower extremity was 9 score compared to the presurgery.

CONCLUSION

Nerve transfer generally improves sensorimotor functions in paralyzed limbs and bladder control following CNS injury. The technique effectively creates a 'bypass' for signals and facilitates functional recovery by leveraging neural plasticity. It suggested a future of surgery, neurorehabilitation and robotic-assistants converge to improve outcomes for CNS.

Volar versus dorsal approach for supinator to posterior interosseous nerve transfer: An anatomical study in cadavers

INTRODUCTION

Supinator to posterior interosseous nerve (SPIN) transfer allows reconstruction of finger/thumb extension and thumb abduction for low radial nerve palsy, incomplete C6 tetraplegia, and brachial plexus injury affecting C7-T1. No study has compared dorsal versus volar approach to perform SPIN transfer. This comparison is studied in the present work, assessing supinator motor branch length and ability to achieve nerve transfer from either approach.

METHODS

Ten fresh frozen cadavers were randomly allocated to receive either a dorsal or volar approach to PIN and supinator radial and ulnar branches (RB = radial, UB = ulnar). Supinator head innervation patterns were documented. RB and UB lengths, forearm lengths measured from ulnar styloid to olecranon, visualization of extensor carpi radialis brevis (ECRB) motor nerve without additional dissection, and ability to perform tension-free nerve transfer were assessed.

RESULTS

Nine of 10 specimens had supinator branches innervating both heads. The ECRB nerve was visualized in all volar but only one dorsal approach. No significant differences in forearm length were found. Volar with elbow extended: mean RB length was 35 ± 7.8 mm and UB was 37.8 ± 9.3 mm. Dorsal with elbow extended: mean RB length was 30 ± 4.1 mm and UB was 38.8 ± 7.3 mm. Dorsal with elbow flexed 90°: RB was 25.6 ± 3.8 mm and UB was 34.8 ± 4.8 mm. No significant differences were found in branch lengths between approaches (dorsal vs. volar UB, p = .339; dorsal vs. volar RB, p = .117). All limbs achieved tension-free coaptation.

CONCLUSION

Neither approach demonstrated superiority in achieving tension-free nerve transfer. Volar permitted immediate identification of ECRB nerve whereas this was only visualized in one dorsal specimen without additional dissection. Overall, the volar approach allows direct coaptation in elbow extension, mimicking maximal physiologic tension for neurorrhaphy. It simultaneously permits additional procedures for pinch reconstruction via single exposure, circumventing limb/microscope maneuvering, dorsal dissection, and increased operative time. Ultimate choice of approach should depend on surgeon familiarity and potential need for additional simultaneous transfers.

The Anatomy of Nerve Transfers Used in Tetraplegic Hand Reconstruction

PURPOSE

To evaluate the anatomy of nerve transfers used to reconstruct wrist extension, hand opening, and hand closing in tetraplegic patients.

METHODS

Nerve transfers were completed on 18 paired cadaveric upper limbs. The overlap of donor and recipient nerves was measured, as well as the distance to the target muscle. Axons were counted in each nerve and branch, with the axon percentage calculated by dividing the donor nerve count by that of the recipient.

RESULTS

Transfers with overlap of the donor and recipient nerve were from the radial nerve branch to extensor carpi radialis brevis to anterior interosseous nerve (AIN) and from the branch(es) to supinator to posterior interosseous nerve. The extensor carpi radialis brevis to AIN had the shortest distance to the target, with the branch to brachialis to AIN being the longest. The nerve transfers for wrist extension had the highest axon percentage. Of the transfers for hand closing, the brachialis to AIN had the highest axon percentage, and the branch to brachioradialis to AIN had the lowest.

CONCLUSIONS

The anatomical features of nerve transfers used in tetraplegic hand reconstruction are variable. Differences may help explain clinical outcomes.

CLINICAL RELEVANCE

This study demonstrates which nerve transfers may be anatomically favorable for restoring hand function in tetraplegic patients.

Single-stage double motor nerve transfer for all finger flexion in iatrogenic C8-T1 spinal nerve injury: a case report and review of literature

Restoration of hand function after C8-T1 spinal nerve injury is challenging. We report a case of a young patient who underwent single-stage transfer of extensor carpi radialis brevis (ECRB) branch of radial nerve to flexor digitorum superficialis (FDS) branch of median nerve and transfer of brachialis branch of musculocutaneous nerve to anterior interosseous nerve (AIN), aiming for restoration of all finger flexion in iatrogenic C8-T1 spinal nerve injury after the resection of a dumbbell-shaped C8 neurofibroma. At 18 months after the operation, the fingers and thumb functions were successfully restored. The operation might be useful for restoration of hand function in selected patients with C8, T1 brachial plexus injury. From the literature review, this is the first case that the technique of double motor nerve transfer and the transfer of ECRB branch to FDS branch were used to restore finger flexion in a patient with brachial plexus injury.

Combined Nerve and Tendon Transfers for C7-T1 Brachial Plexus Avulsion Injury

BACKGROUND

In patients with C7-T1 brachial plexus avulsions, complete loss of hand function is commonly seen. However, the reconstruction of hand function is difficult.

OBJECTIVE

To report the outcomes of hand function recovery after combined nerve and tendon transfers in C7-T1 brachial plexus injury.

METHODS

From 2012 to 2019, 8 patients with C7-T1 brachial plexus injury underwent combined nerve and tendon transfers for hand function restoration, which included the following: (1) the pronator teres motor branch to the anterior interosseous nerve and brachialis motor branch to the flexor digitorum superficialis branch for finger flexion, (2) the supinator motor branch to the posterior interosseous nerve for finger extension, (3) the brachioradialis tendon transfer for thumb opposition, and (4) the radial branch of the superficial radial nerve to the sensory branch of the ulnar nerve for sensory reconstruction. Patients were evaluated for functional improvement of finger flexion, finger extension, thumb opposition, and sensory recovery.

RESULTS

No clinical donor deficits were observed. Seven of eight patients recovered finger and thumb flexion (4 patients scored British Medical Research Council grade M4 and 3 scored M3). The average grip strength was 3.4 kg. All patients regained finger extension (4 scored M4 and 4 scored M3), thumb opposition, and protective sensation on the ulnar hand. Patients were able to use their reconstructed hands in daily lives.

CONCLUSION

Combined nerve and tendon transfers are reliable and effective. This strategy could be an option for hand function reconstruction after C7-T1 brachial plexus injury.

Nerve Transfer of Brachialis Branch to Anterior Interosseus Nerve Using In Situ Lateral Antebrachial Cutaneous Nerve Graft in Tetraplegia

PURPOSE

Reconstruction of finger motion is a therapeutic goal in tetraplegic patients. Although nerve transfer of the brachialis branch of the musculocutaneous nerve to the anterior interosseus nerve has been previously described, this results in unreliable reinnervation because the donor nerve is proximal to the target muscle. We describe an alternative technique in which nerve transfer is performed using the lateral antebrachial cutaneous nerve as a vascular in situ nerve graft. The clinical results are reported.

METHODS

Nine upper limbs of 6 patients (mean age 25 years) with tetraplegia were subjected to brachialis-to-anterior interosseus nerve transfer using the lateral antebrachial cutaneous nerve as a vascular in situ nerve graft, at a mean of 6 months after injury. Additional supinator branch transfer to the posterior interosseous nerve was performed for 6 upper limbs and to the flexor digitorum superficialis motor branch for 1 upper limb.

RESULTS

At a mean of 2 years of follow-up, thumb and finger flexion strength scored M3-M4 in 5 of the 9 limbs according to the Medical Research Council scale. Key pinch and grip pinch averaged 0.6 kg (range, 0-1.0 kg) and 2.2 kg (range, 0-8 kg), respectively. No donor-site deficit was observed.

CONCLUSIONS

Brachialis-to-anterior interosseus nerve transfer with an in situ lateral antebrachial cutaneous nerve graft can be used to reconstruct thumb and finger flexion in tetraplegic patients. Combined with supinator-to- posterior interosseous nerve transfer, simultaneous active extension of the fingers can be achieved.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic V.

Nerves transfers for functional hand recovery in traumatic lower brachial plexopathy

Background:

Distal nerve transfers are an innovative modality for the treatment of C8-T1 brachial plexus lesions. The purpose of this case series is to report the authors’ results with hand restoration function by nerve transfer in patients with lower brachial plexus injury.

Methods:

Three consecutive nerve transfers were performed in a series of 11 patients to restore hand function after injury to the lower brachial plexus: brachialis motor branch to anterior interosseous nerve (AIN) and supinator branch to the posterior interosseous nerve (PIN) in a first surgical procedure, and AIN to pronator quadratus branch of ulnar nerve between 4 and 6 months later.

Results:

In all, 11 male patients underwent 33 surgical procedures. Time between brachial plexus injury and surgery was a mean of 11 months (range 4–13 months). Postoperative follow-up ranged from 12 to 24 months. We observed recovery of M3 or better finger flexion strength (AIN) and wrist extension (PIN) in 8 of the 11 surgically treated upper limbs. These patients recovered full thumb and finger extension between 6 and 12 months of surgery, without significant loss of donor function.

Conclusion:

Nerve transfers represent a way of restoring volitional control of upper extremity function in patients with C8-T1 brachial plexus injury.

Delayed Transfer of the Extensor Carpi Radialis Brevis Branch of the Radial Nerve to the Anterior Interosseous Nerve for Restoration of Thumb and Index Finger Flexion: Case Report

High median nerve injuries (HMNIs) are rare lesions involving the upper extremities and affect the median nerve from its origin to the emergence of the anterior interosseous nerve (AIN). Proximal reconstruction has long been considered the gold standard in treating HMNI, but thumb and index flexion and pinch and grip weakness are consistently not recovered. We report the surgical results of a patient affected by an HMNI with partial spontaneous recovery after a gunshot wound. AIN function was successfully restored in a delayed fashion by transferring the radial nerve branch to the extensor carpi radialis brevis to the AIN.

Comparative study of pronator teres branch transfer and brachialis motor branch transfer to the anterior interosseous nerve to treat lower brachial plexus injury in rats

Distal nerve transfer is used to treat lower brachial plexus palsy, but outcome series on these transfer procedures following lower plexus injuries are sparse. The objective of this study is to compare treatment outcomes after nerve transfer using the brachialis motor branch (BMB) versus that using the pronator teres motor branch (PTMB). One hundred twenty adult rats with C8T1 nerve root avulsion were randomly divided into three groups (40 each): A: BMB transfer to the anterior interosseous nerve (AIN), B: PTMB transfer to the AIN, and C: no repair. Electrophysiological examination result, muscle tension test result, muscle weight and muscle fiber cross-sectional area of the flexor digitorum profundus and flexor pollicis longus, and number of myelinated nerve fibers in the AIN were compared among the groups to evaluate the treatment outcome. Nerve regeneration and muscle recovery in group B was better than those in group A at 4 and 8 weeks postoperatively (P < 0.05). There was no significant difference in the myelinated nerve fibers in groups A and B at 12 and 16 weeks postoperatively. The rats in group B showed greater and more significant improvement in other measured values than those in group A (P < 0.05). In conclusion, the PTMB seems a better donor nerve than the BMB for distal nerve transfer to treat lower brachial plexus injury according to the electrophysiological and histological examination in this rat study.

Brachioradialis to flexor digitorum profundus tendon transfer to restore finger flexion

Introduction:

The main deformity following an adult lower brachial plexus injury is the loss of finger flexion. Distal nerve transfers have been used to restore finger and thumb flexion followed by tendon transfers for intrinsic replacement for opening of the fingers. When patients present beyond 6 months, only tendon transfers are applicable. Since the brachioradialis (BR) is always spared in such injuries, it is the ideal muscle to provide finger flexion. Wrist extensor power may not be normal for the use of the radial wrist extensor to serve as donor. BR to FDP transfer provides reasonable flexion range and an acceptable hand function to permit activities of daily living, when associated with ancillary procedures like opponensplasty, PIPJ arthrodesis.

Materials and Methods:

Eleven patients underwent a BR to FDP tendon transfer between January 2013 and January 2017 of which eight patients came for follow-up.

Results:

Four of the eight patients got a functionally useful hand to carry out activities of daily living with hook grip, span grasp, key pinch, chuck grip and pulp pinch. These patients also underwent simultaneous or secondary ancillary procedures. Four of the patients need secondary procedures to further improve functionality of the hand inspite of having a flexion range.

Conclusion:

The BR is an effective donor in providing adequate range and power of finger flexion in lower plexus injuries.

Brachialis muscle transfer for reconstructing digital flexion after brachial plexus injury or forearm injury

Restoration of digital flexion after brachial plexus injury or forearm injury has been a great challenge for hand surgeons. Nerve transfer and forearm donor muscle transfer surgeries are not always feasible. The present study aimed at evaluating the effectiveness of restoring digital flexion by brachialis muscle transfer. Ten lower brachial plexus- or forearm-injured patients were enrolled. After at least 12 months following surgery, the middle-finger-to-palm distance was less than 2.5 cm in six patients. In the other four patients with less satisfactory results, secondary tenolysis surgery was performed and the middle-finger-to-palm distances were reduced to 2.0-4.0 cm. The average grasp strength was 20 ± 4 kg. Elbow flexion was not adversely affected. In conclusion, brachialis muscle transfer is an effective method for reconstructing digital flexion, not only in lower brachial plexus injury, but also in forearm injury patients.

LEVEL OF EVIDENCE

IV.

Outcome of Finger Extension After Nerve Transfer to Repair C7-T1 Brachial Plexus Palsy in Rats: Comparative Study of the Supinator Motor Branch Transfer to the Posterior Interosseous Nerve and the Contralateral C7 Transfer to the Lower Trunk

BACKGROUND

Functional recovery following supinator motor branch transfer requires further investigation.

OBJECTIVE

To compare the outcome of finger extension after supinator motor branch transfer or contralateral C7 (cC7) transfer in C7-T1 brachial plexus palsies in rats.

METHODS

In this study, 120 adult rats underwent C7-T1 nerve root avulsion and received different nerve transfer repairs: group A, cC7 nerve transfer to the lower trunk; group B, supinator motor branch nerve transfer to the posterior interosseous nerve (PIN); and group C, no repair. The ethology of the rats, latency and amplitude of the compound muscle action potential from the PIN, muscle mass and muscle fiber cross-sectional area of the extensor digitorum communis and extensor carpi ulnaris, and number of myelinated nerve fibers in the PIN were examined postoperatively.

RESULTS

There was no finger extension in group C. We observed finger extension in groups A and B 50.2 ± 5.66 and 13.1 ± 2.08 days postoperatively, respectively. Finger extension restoration in group B was greater than that in group A at 4, 8, and 12 weeks postoperatively ( P < .05). Sixteen weeks after surgery, the recovery rate of the myelinated nerve fibers in group A was marginally higher than that in group B, but the difference was not significant. Of the other measured values, group B showed a greater and significant improvement compared to group A ( P < .05).

CONCLUSION

Supinator motor branch transfer allows for faster recovery and is a more effective procedure for restoring finger extension in C7-T1 brachial plexus palsies.

Multiple nerve and tendon transfers: a new strategy for restoring hand function in a patient with C7-T1 brachial plexus avulsions

C7-T1 brachial plexus palsies result in a loss of finger motion and hand function. The authors have observed that finger flexion motion can be recovered after a brachialis motor branch transfer. However, finger flexion strength after this procedure merely corresponds to Medical Research Council Grades M2-M3, lowering the grip strength and practical value of the reconstructed hand. Therefore, they used 2 donor nerves and accomplished double nerve transfers for stronger finger flexion. In a patient with a C7-T1 brachial plexus injury, they transferred the pronator teres branch to the anterior interosseous nerve and the brachialis motor branch to the flexor digitorum superficialis branch for reinnervation of full finger flexors. Additionally, the supinator motor branch was transferred for finger extension, and the brachioradialis muscle was used for thumb opposition recovery. Through this new strategy, the patient could successfully accomplish grasping and pinching motions. Moreover, compared with previous cases, the patient in the present case achieved stronger finger flexion and grip strength, suggesting practical improvements to the reconstructed hand.

Nerve Transfers for the Restoration of Wrist, Finger, and Thumb Extension After High Radial Nerve Injury

High radial nerve injury is a common pattern of peripheral nerve injury most often associated with orthopedic trauma. Nerve transfers to the wrist and finger extensors, often from the median nerve, offer several advantages when compared to nerve repair or grafting and tendon transfer. In this article, we discuss the forearm anatomy pertinent to performing these nerve transfers and review the literature surrounding nerve transfers for wrist, finger, and thumb extension. A suggested algorithm for management of acute traumatic high radial nerve palsy is offered, and our preferred surgical technique for treatment of high radial nerve palsy is provided.

Neurotization of free gracilis transfer with the brachialis branch of the musculocutaneous nerve to restore finger and thumb flexion in lower trunk brachial plexus injury: an anatomical study and case report

OBJECTIVE

To investigate the feasibility of using free gracilis muscle transfer along with the brachialis muscle branch of the musculocutaneous nerve to restore finger and thumb flexion in lower trunk brachial plexus injury according to an anatomical study and a case report.

METHODS

Thirty formalin-fixed upper extremities from 15 adult cadavers were used in this study. The distance from the point at which the brachialis muscle branch of the musculocutaneous nerve originates to the midpoint of the humeral condylar was measured, as well as the length, diameter, course and branch type of the brachialis muscle branch of the musculocutaneous nerve. An 18-year-old male who sustained an injury to the left brachial plexus underwent free gracilis transfer using the brachialis muscle branch of the musculocutaneous nerve as the donor nerve to restore finger and thumb flexion. Elbow flexion power and hand grip strength were recorded according to British Medical Research Council standards. Postoperative measures of the total active motion of the fingers were obtained monthly.

RESULTS

The mean length and diameter of the brachialis muscle branch of the musculocutaneous nerve were 52.66±6.45 and 1.39±0.09 mm, respectively, and three branching types were observed. For the patient, the first gracilis contraction occurred during the 4th month. A noticeable improvement was observed in digit flexion one year later; the muscle power was M4, and the total active motion of the fingers was 209°.

CONCLUSIONS

Repairing injury to the lower trunk of the brachial plexus by transferring the brachialis muscle branch of the musculocutaneous nerve to the anterior branch of the obturator nerve using a tension-free direct suture is technically feasible, and the clinical outcome was satisfactory in a single surgical patient.

Double Distal Intraneural Fascicular Nerve Transfers for Lower Brachial Plexus Injuries

PURPOSE

To evaluate outcomes following transfer of the supinator motor branch of the radial nerve (SMB) to the posterior interosseous nerve (PIN) and the pronator teres motor branch of median (PTMB) to the anterior interosseous nerve (AIN) in patients with lower brachial plexus injuries.

METHODS

Since December 2010, 4 patients have undergone combined transfer of the SMB to PIN and PTMB to AIN for lower brachial plexus palsies. The study was prospectively designed, and the patients were followed for 4 years to monitor their functional improvement.

RESULTS

One patient failed to return after his 4-month postoperative visit. The other 3 patients all regained M4 thumb and finger extension, and 2 recovered M4 thumb and finger flexion at the final evaluation, a mean 30 months after the nerve transfer surgeries.

CONCLUSIONS

Combined transfer of the SMB to PIN and PTMB to AIN may lead to successful recovery of digital extrinsic flexion and extension in lower brachial plexus injuries.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Targeted Muscle Reinnervation of the Brachium: An Anatomic Study of Musculocutaneous and Radial Nerve Motor Points Relative to Proximal Landmarks

PURPOSE

Targeted muscle reinnervation (TMR) offers enhanced prosthetic use by harnessing additional neural control from unused nerves in the amputated limb. The purpose of this study was to document the location and number of motor end plates to each muscle commonly used in TMR in the brachium relative to proximally based bony landmarks.

METHODS

We dissected 18 matched upper limbs (9 fresh-frozen cadavers). The locations of each of the nerves' muscular insertions into the medial biceps and brachialis were measured relative to the anterolateral tip of the acromion. The terminal branches to the lateral triceps were measured relative to the posterolateral tip of the acromion. Both the number of branches and the location of the muscular insertions were documented. Common descriptive statistics were used to describe the data.

RESULTS

There was a median of 2 branches to the medial biceps located 19.6 cm from the anterolateral tip of the acromion (range, 15-25 cm). There was a median of 3.5 branches to the brachialis located 24.2 cm from the anterolateral tip of the acromion (range, 19-27.5 cm). There was a median of 2.5 branches to the lateral triceps located 21.6 cm from the posterolateral tip of the acromion (range, 11-29 cm). The mean distances to the primary branch muscle and the number of smaller branches were not significantly different when compared by sex or side.

CONCLUSIONS

Motor points for the medial biceps, brachialis, and lateral triceps can be identified reliably using proximal landmarks in targeted muscle reinnervation.

CLINICAL RELEVANCE

The data obtained from this study may assist the surgeon in localizing the nerve branches and muscular insertions for the commonly used muscles for TMR of the brachium.

Origination of the muscular branches of the median nerve: an electrophysiological study

BACKGROUND

In lower brachial plexus injury, finger flexion after brachialis motor branch transfer is relatively weak. We sought to screen potential branches of the median nerve from the upper trunk for strengthening finger flexion in addition to the brachialis motor branch. However, the spinal origin of the muscular branches of the median nerve based on electrophysiological study was unclear.

OBJECTIVE

To determine the spinal origin of the muscular branches of the median nerve.

METHODS

An intraoperative electrophysiological study was carried out in 18 patients who underwent contralateral C7 nerve transfer. After exposure of the brachial plexus nerve roots on the healthy side, the amplitude of the compound muscle action potential of each median nerve-innervated muscle was recorded while the different nerve roots were stimulated.

RESULTS

The pronator teres received fibers from C5, C6, and C7. It had more contribution from C5 and C6 than from C7 (P<.05). The flexor carpi radialis was innervated mainly by C6 and C7. The nerve branches of the palmaris longus and flexor digitorum superficialis stemmed primarily from C7 and the lower trunk, and no significant difference was found between them (P>.05). The flexor digitorum profundus, flexor pollicis longus, pronator quadratus, and abductor pollicis brevis were innervated predominantly by the lower trunk (P<.05).

CONCLUSION

This electrophysiological study indicates that the pronator teres branch might be the most feasible alternative donor nerve to supplement the brachialis motor branch and strengthen finger flexion after lower brachial plexus injury.

The median nerve consistently drives flexion of the distal phalanx of the ring and little fingers: Interest in finger flexion reconstruction by nerve transfers

Surgeons believe that in high ulnar nerve lesion distal interphalangeal joint (DIP) flexion of the ring and little finger is abolished. In this article, we present the results of a study on innervation of the flexor digitorum profundus of the ring and little fingers in five patients with high ulnar nerve injury and in 19 patients with a brachial plexus, posterior cord, or radial nerve injury. Patients with ulnar nerve lesion were assessed clinically and during surgery for ulnar nerve repair we confirmed complete lesion of the ulnar nerve in all cases. In the remaining 19 patients, during surgery, either the median nerve (MN) or the anterior interosseous nerve (AIN) was stimulated electrically and DIP flexion of the ring and little fingers evaluated. All patients with high ulnar nerve lesions had active DIP flexion of the ring and little fingers. Strength scored M4 in the ring and M3-M4 in the little finger. Electrical stimulation of either the MN or AIN produced DIP flexion of the ring and little fingers. Contrary to common knowledge, we identified preserved flexion of the distal phalanx of the ring and little fingers in high ulnar nerve lesions. On the basis of these observations, nerve transfers to the AIN may provide flexion of all fingers.

Restoration of hand function in C7-T1 brachial plexus palsies using a staged approach with nerve and tendon transfer

Brachial plexus palsies of C7-T1 result in the complete loss of hand function, including finger and thumb flexion and extension as well as intrinsic muscle function. The task of reanimating such a hand remains challenging, and so far there has been no reliable neurological reconstructive method for restoring hand function. The authors aimed to establish a reliable strategy to reanimate the paralyzed hand. Two patients had sustained C7-T1 complete lesions. In the first stage of the operative procedure, a supinator motor branch to posterior interosseous nerve transfer was performed with brachialis motor branch transfer to the median nerve to restore finger and thumb extension and flexion. In the second stage, the intact brachioradialis muscle was used for abductorplasty to restore thumb opposition. Both patients regained good finger extension and flexion. Thumb opposition was also attained, and overall hand function was satisfactory. The described strategy proved effective and reliable in restoring hand function after C7-T1 brachial plexus palsies.

Pronator Teres Branch Transfer to the Anterior Interosseous Nerve for Treating C8T1 Brachial Plexus Avulsion

BACKGROUND:

The treatment of C8T1 avulsion is challenging for neurosurgeons. Various methods for the restoration of finger flexion are used. However, most of these methods have different disadvantages and cannot restore the full active range of motion of the fingers.

OBJECTIVE:

To determine the feasibility of the pronator teres branch transfer to the anterior interosseous nerve with anatomic study and to use this method in 1 case.

METHODS:

The upper limbs of 15 fresh cadavers were dissected to identify the main trunk of the median nerve, the pronator teres branch, and the anterior interosseous nerve. The mean number and length of the pronator teres branches were recorded. The anterior interosseous nerve was dissected atraumatically to the most proximal level where the fibers of the anterior interosseous nerve did not mingle with the fibers of the main trunk of the median, which was defined as the atraumatic level of the anterior interosseous nerve. A line joining the most protruding point of the medial condyle and lateral condyle of the humerus was used as a measurement landmark. Pronator teres branch transfer to the anterior interosseous nerve was performed in 1 patient with C8T1 avulsion.

RESULTS:

The mean number of the pronator teres branches was 2.37 ± 0.49. The mean length of the pronator teres branches was 9.64 ± 0.71 mm. The mean distance between the point where the pronator teres branches originated and the landmark line was 3.87 ± 0.34 mm. The mean distance between the atraumatic level of the anterior interosseous nerve and the landmark line was −5.46 ± 0.73 mm. Transfer of the pronator teres was used to innervate the anterior interosseous nerve in 1 patient with C8T1 avulsion. When assessed 14 months after the operation, a full active range of motion of the fingers had been restored, and the patient's finger flexor muscles had regained grade 4 power.

CONCLUSION:

The pronator teres can be transferred to the anterior interosseous nerve directly at the elbow level. This operation was performed successfully in 1 patient, who exhibited finger flexion recovery.

Brachial plexus injury in adults: Diagnosis and surgical treatment strategies

Adult post traumatic Brachial plexus injury is unfortunately a rather common injury in young adults. In India the most common scenario is of a young man injured in a motorcycle accident. Exact incidence figures are not available but of the injuries presenting to us about 90% invole the above combination This article reviews peer-reviewed publications including clinical papers, review articles and Meta analysis of the subject. In addition, the authors' experience of several hundred cases over the last 15 years has been added and has influenced the ultimate text. Results have been discussed and analysed to get an idea of factors influencing final recovery. It appears that time from injury and number of roots involved are most crucial.

Spinal nerve origins of the muscular branches of the radial nerve: an electrophysiological study

BACKGROUND

In injuries of the lower brachial plexus, finger flexion can be restored by nerve or tendon transfer. However, there is no technique that can guarantee good recovery of finger and thumb extension.

OBJECTIVE

To determine the spinal nerve origins of the muscular branches of the radial nerve and identify potential intraplexus donor nerves for neurotization of the posterior interosseous nerve in patients with lower brachial plexus injuries.

METHODS

An intraoperative electrophysiological study was carried out during 16 contralateral C7 nerve transfers. The compound muscle action potential of each muscle innervated by the radial nerve was recorded while the C5-T1 nerves were individually stimulated.

RESULTS

The triceps brachii muscle primarily received root contributions from C7. The C5 and C6 nerve roots displayed greater amplitudes for the brachioradialis and supinator muscles compared with those of the C7, C8, and T1 nerve roots (P < .05). The extensor carpi radialis branch was innervated by C5, C6, and C7, and no significant differences were detected between them (P > .05). The amplitudes obtained for the extensor digitorum communis branch were the largest from C7 and C8, without a significant difference between them (P > .05), whereas the amplitudes of the extensor carpi ulnaris and extensor pollicis longus were largest from the C8 root (P < .05).

CONCLUSION

The supinator muscle branch is likely the best donor nerve for the repair of lower brachial plexus injuries affecting muscles that are innervated by the posterior interosseous nerve.

Brachialis-to-extensor carpi radialis longus selective nerve transfer to restore wrist extension in tetraplegia: case report

Active wrist extension allowing tenodesis grip is the key function in high-level tetraplegic patients. It is absent and cannot be restored by traditional tendon transfer in patients who have no transferable muscle below the elbow. We present a 36-year-old man with high-level tetraplegia treated 12 months after injury who regained active wrist extension after transfer of the brachialis muscle branch of the musculocutaneous nerve to the extensor carpi radialis longus muscle branch of the radial nerve. No functional deficit of elbow flexion occurred after reconstruction.

Transfer of the nerve to the brachioradialis muscle to the anterior interosseous nerve for treatment for lower brachial plexus lesions: case report

In lower lesions of the brachial plexus (C8-T1) there is good function of the shoulder, elbow, and wrist, although that of the hand is impaired. Reconstruction of finger flexion is generally obtained by tendon transfer. We present a case report involving transfer of the motor nerve branch of the brachioradialis muscle to the anterior interosseous nerve to restore finger flexion in acute lower brachial plexus lesion.

Clinical use of supinator motor branch transfer to the posterior interosseous nerve in C7–T1 brachial plexus palsies

Object

In C7–T1 brachial plexus palsies, finger extension and flexion are absent. At the authors' institution, finger flexion has been successfully reconstructed by transferring the brachialis motor branch to the anterior interosseous nerve. However, there is no reliable method for restoring finger extension. In the present study, the authors examined the surgical results of transferring the supinator motor branch to the posterior interosseous nerve.

Methods

Since October 2007, the authors have performed a supinator motor branch transfer to the posterior interosseous nerve in 4 patients. The patients underwent follow-up every 3–4 months postoperatively.

Results

Finger extension appeared between 5 and 9 months in the first 3 cases and demonstrated promising improvement over time. One recent case remains under follow-up.

Conclusions

A supinator motor branch to posterior interosseous nerve transfer leads to reliable recovery of thumb and finger extension. Therefore, it is a viable option for C7–T1 brachial plexus palsies.

Nerve transfers in the forearm and hand

In the forearm, vital and expendable functions have been identified, and tendon transfers use these conventions to maximize function and minimize disability. Using similar concepts, distal nerve transfers offer a reconstruction that often is superior to reconstruction accomplished by traditional grafting. The authors present nerve transfer options for restoring motor and sensory deficits within each nerve distribution on the forearm and hand.

ORIGINATION OF THE BRACHIALIS BRANCH OF THE MUSCULOCUTANEOUS NERVE

OBJECTIVE

To test an innovative method to study the origin of a specific nerve or of the nerve fibers innervating a given muscle on the healthy upper limb of a human being and to find the rationale for the brachialis branch of musculocutaneous nerve transfer.

METHODS

An intraoperative electrophysiological study was conducted comprising 27 cases of contralateral C7 transfer. The goal of the study was to record compound muscle action potential of the brachialis muscle while various nerve roots of the brachial plexus were stimulated.

RESULTS

Analysis of compound muscle action potential suggested that the brachialis branch of the musculocutaneous nerve is composed of fibers from the C5, C6, and C7 nerve roots and that the C5 and C6 nerve roots are the major origin for the brachialis branch of musculocutaneous nerve fibers.

CONCLUSION

The technique proposed here was a more direct and functional method of tracing the origin of a specific nerve or of the nerve fibers innervating a given muscle on the healthy upper limb of a live patient.