Transfer of axillary nerve branches to reconstruct elbow extension in tetraplegics: A laboratory investigation of surgical feasibility

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.

Axillary to Radial Nerve Transfer for Recovery of Elbow Extension After Spinal Cord Injury

BACKGROUND AND OBJECTIVES

Cervical spinal cord injuries (SCI) result in severe loss of function and independence. Nerve transfers have become a powerful method for restoring upper extremity function, the most critical missing function desired by this patient population. Recovery of active elbow extension allows for expansion of one's workspace to reach for objects and stabilizes control at the elbow joint. Without triceps function, a patient with a cervical SCI is rendered entirely helpless when in the supine position. Our objective was to provide a concise description of the transfer of branches of the axillary nerve (AN) to the long head of the triceps branch of the radial nerve (RN) for restoration of elbow extension after cervical SCI.

METHODS

An anterior, axillary approach is used for the transfer of the nerve branches of the AN (which may include branches to the teres minor, posterior deltoid, or even middle deltoid) to the long head of the triceps branch of the RN. Preoperative assessment and intraoperative stimulation are demonstrated to direct optimal selection of axillary branch donors.

RESULTS

The axillary approach provides full access to all branches of the AN in optimal proximity to triceps branches of the RN and allows for tension-free coaptation to achieve successful recovery of elbow extension. Final outcomes may not be achieved for 18 months. Of our last 20 patients with greater than 12-month follow-up, 13 have achieved antigravity strength in elbow extension, 4 are demonstrating ongoing progression, and 3 are definitive failures by 18 months.

CONCLUSION

The axillary to RN transfer is an important intervention for recovery of elbow extension after cervical SCI, which significantly improves quality of life in this patient population. Further large population outcomes studies are necessary to further establish efficacy and increase awareness of these procedures.

Current Concepts in Elbow Extension Reconstruction for the Tetraplegic Patient

Individuals with C5 or C6 spinal cord injury (SCI) have paralysis of the triceps brachii, and the subsequent loss of elbow extension makes it impossible to reliably use their hands above shoulder level because of the inability to hold the elbow extended against gravity. For persons with cervical SCI, elbow extension can be restored with both tendon and nerve transfers. Elbow extension is necessary for dressing, eating, wheelchair locomotion, pressure relief maneuvers, independent transfers, and reaching objects above shoulder level. Deltoid-to-triceps and biceps-to-triceps tendon transfers have established efficacy and a longer history of use. Transfer of motor branches from the axillary nerve to triceps motor branches is new with no current published prospective studies but shows early promise. This review aims to highlight the amazing potential these procedures can have on the independence and quality of life for people with quadriplegia. Despite the immense benefit possible, fewer than 14% of eligible people with cervical SCI in the United States receive upper limb reconstructive surgery. Surgical timing is critical. A broader understanding and raised awareness of reconstructive options for elbow extension in people with quadriplegia will increase recognition of eligible patients and speed referral time to the appropriate practitioner.

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.

Donor activation focused rehabilitation approach to hand closing nerve transfer surgery in individuals with cervical level spinal cord injury

STUDY DESIGN

Case Series.

OBJECTIVES

To describe the donor activation focused rehabilitation approach (DAFRA) in the setting of the hand closing nerve transfers in cervical spinal cord injury (SCI) so that therapists may apply it to treatment of individuals undergoing this procedure.

SETTING

United States of America-Academic Level 1 Trauma Center.

METHODS

We reviewed the records of individuals with cervical SCI who underwent nerve transfer to restore hand closing and post-surgery DAFRA therapy at our institution. The three post-surgery phases of DAFRA included (1) early phase (0-12 months) education, limb preparation, and donor activation exercises, (2) middle phase (12-24 months) volitional recipient muscle activation and (3) late phase (18 + months) strengthening and incorporation of motion in activities of daily living.

RESULTS

Subtle gains in hand closing were first observed at a mean of 8.4 months after hand closing nerve transfer surgery. Remarkable improvements including discontinuation of assistive devices, independence with feeding and urinary function, and measurable grip were observed. Function continued to improve slowly for one to two more years.

CONCLUSIONS

A deliberate, slow-paced (monthly for >2 years post-surgery) and incremental therapy program-DAFRA-can be used to improve outcomes after nerve transfer to restore hand closing in cervical SCI.

SPONSORSHIP

This work was made possible by funding from the Craig H. Neilsen Foundation Spinal Cord Injury Research on the Translation Spectrum (SCIRTS) Grant: Nerve Transfers to Restore Hand Function in Cervical Spinal Cord Injury (PI: Ida Fox).

Functional outcome after transfer of brachialis on anterior interosseous and supinator on posterior interosseous nerves: A preliminary report

OBJECTIVE

Traumatic spinal cord injury (SCI) resulting in tetraplegia is a leading cause of morbidity among young adults worldwide and its management remains challenging. Restoring hand function in these patients must be considered a top priority with great impact on their quality of life (QOL); although nerve and tendon transfer have been extensively described, type of procedure to be chosen is not standardized and few studies have determined the functional outcome of those procedure and their impact on QOL is still poorly assessed. We report a preliminary retrospective study regarding feasibility and functional outcomes of nerve transfer procedures including bilateral brachialis nerve on anterior interosseous nerve (AIN) and supinator branch on posterior interosseous nerve (PIN) for hand reanimation following SCI focusing on the impact of these procedures on QOL.

METHODS

We performed a retrospective study involving patient sustained SCI and underwent nerve transfer of brachialis branch from musculocutaneous nerve on AIN and supinator branch from the trunk of the radial nerve on the PIN. We included 11 patients (14 limbs) with traumatic SCI resulting in C4 level tetraplegia in five patients, C5 in four and C6 and C7 in one case each, with a median age of 31.5 years underwent surgery at a median of 10 months after injury; including both transfers in 10 cases and AIN reanimation only in one. Functional assessment including medical research council (MCR) grade, graded redefined assessment of strength sensation and prehension (GRASSP) and spinal cord independence measure (SCIM) were performed at least 12 months follow up.

RESULTS

Thirteen PIN innervated muscles achieved an MRC score ≥3/5 whereas AIN supplied muscles in 5 out of 15. GRASSP qualitative measure improved from a baseline value of 1 to 2, while quantitative measure passed from 1 to 3 after 12 months; the difference was statistically significant (p = .005 and p = .008, respectively). SCIM self-care sub-score also statistically significant improved from 3 to 4 at 12 months (p = .016). No complication or donor morbidity occurred.

CONCLUSIONS

Functional performance has been significantly improved by nerve transfer procedures 1 year after surgery. Nerve transfers may represent a valuable option for the restoration of the hand function in patients with tetraplegia with minor or no morbidity.

Surgical restoration of the upper limb in cervical spinal cord injury patients

Prior to the 1950s, relatively few patients who suffered a transection of the cervical spinal cord survived their injury. Improved medical care and better coordination have resulted in greater numbers of patients surviving and leaving the hospital. The pioneering work of individual surgeons during the 1960s and 1970s stimulated interest in surgical restoration of upper limb function in tetraplegic patients. Since the publication of Moberg's monograph in 1978, surgical improvement of the upper limbs is regarded as one of the options that should be offered to tetraplegic individuals to improve their function. Patients are classified according to the level of spinal cord injury and the residual motor function (international classification: groups 1 to 9). Surgical procedures are adapted to the motor level for each group of patients. Indications for these procedures are well standardized, the techniques are well mastered, and predictable results can be expected. New nerve transfer techniques have been developed in recent years; they are currently being evaluated.

Nerve transfers in tetraplegia: a review and practical guide

INTRODUCTION

Spinal cord injury (SCI) may lead to tetraplegia. Several nerve transfers have been successfully used for the restoration of the upper limb in tetraplegia. Reconstruction of an upper limb is individualized based on the functional level. In this study, the authors reviewed nerve transfers based on the injury level for the restoration of upper limb function in tetraplegia.

EVIDENCE ACQUISITION

We performed this study to review nerve transfers in tetraplegia by searching MEDLINE and EMBASE databases to identify relevant articles published through December 2020. We selected studies that reported cases in tetraplegia and extracted information on demographic data, clinical characteristics, operative details, and strength outcomes based on each injury level after surgery.

EVIDENCE SYNTHESIS

Total of 29 journal articles reporting on 275 nerve transfers in 172 upper limbs of 121 patients were included in the review. The mean time between SCI and nerve transfer surgery was 21.37 months (range: 4-156 months), and the follow-up time was 21.34 months (range: 3-38 months). The best outcomes were achieved for the restoration of wrist/finger extension and elbow extension.

CONCLUSIONS

Nerve transfer can provide a new function in tetraplegic patients' upper limbs to improve daily living activities. The type of surgical procedure should be performed based on the functional level of SCI and the individual's needs. Functional recovery occurs more in extensor muscles than flexors. Nerve transfer is a promising option in the reconstruction of upper limb function in tetraplegia.

Upper-Extremity Reconstruction in Tetraplegia: A Critical Analysis Review

Management of tetraplegia should be individualized to a patient's particular deficiencies and functional goals. Surgical decision-making for upper-extremity reconstruction in patients with tetraplegia relies on a thorough physical examination to determine which nerves and muscles remain under volitional control with adequate strength for transfer. Peripheral nerve transfers, either in conjunction with or in place of traditional tendon transfers, enable providers to offer an expanded set of surgical options for patients with tetraplegia who are seeking upper-extremity reconstruction. All upper-extremity reconstructive efforts should be carefully considered with regard to their potential effects on the availability of future reconstructive efforts.

Hand Reconstruction in Children with Spinal Cord Injury

Comprehensive programs for children who sustain traumatic spinal cord injury should incorporate optimizing hand and upper extremity function along with the other traditional pillars of rehabilitation. Children's smaller anatomy, open growth plates, and future skeletal growth, combined with the age-related psychosocial impact of these injuries, require protocols suited to these age-related issues. There is a role for surgical reconstruction, as is the case for adults with traumatic tetraplegia, and surgical outcomes are equally beneficial and long lasting. Strict adherence to surgical indications, and surgical strategies and protocols that incorporate their age-related challenges, are the keys to successful management.

Distal Nerve Transfers to the Triceps Brachii Muscle: Surgical Technique and Clinical Outcomes

PURPOSE

To report the clinical outcomes and describe the surgical technique of triceps muscle reinnervation using 2 different distal nerve transfers: the flexor carpi ulnaris (FCU) fascicle of the ulnar nerve and the posterior branch of the axillary nerve (PBAN) to the triceps nerve branch.

METHODS

A retrospective review of patients undergoing FCU fascicle of ulnar nerve or PBAN to triceps nerve branch transfer was performed. Outcome measures included preoperative and postoperative modified British Medical Research Council (MRC) score, EMG results, and complications.

RESULTS

Between September 2003 and April 2017, 6 patients were identified. Four patients with a traumatic upper trunk and posterior cord palsy underwent ulnar nerve fascicle to triceps nerve transfer. Two patients with a recovering upper trunk following a pan-brachial plexus palsy underwent PBAN to triceps nerve branch transfer. The median age was 30.0 years (range, 18-68 years). Surgery was performed at a median of 6.9 months (range, 5.0-8.9 months) postinjury, with a median follow-up of 18.4 months (range, 7.6-176.3) months. Before surgery, 4 patients exhibited grade M0 and 2 patients exhibited grade M1 triceps strength. Four patients had M5 donor muscle strength and 2 had grade M4. Postoperatively, 4 patients regained MRC grade M4 triceps muscle strength, 1 regained M3, and 1 regained M2. There was no noticeable donor muscle weakness.

CONCLUSIONS

Nerve fascicles to the FCU and PBAN are viable options for obtaining meaningful triceps muscle recovery in a select group of patients.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic V.

Nerve transfer surgery in cervical spinal cord injury: a qualitative study exploring surgical and caregiver participant experiences

PURPOSE

To investigate perceptions of surgical participants and their caregivers regarding novel nerve transfer surgery to restore upper extremity function in cervical level spinal cord injury.

MATERIALS AND METHODS

A qualitative study design was used. A multidisciplinary team developed semi-structured interview guides. Interviews were recorded, transcribed and analyzed using basic text analysis.

RESULTS

Participants had limited information about procedures to improve function after spinal cord injury. When discussing their choice to undergo nerve (as compared to traditional tendon) transfer surgery, they describe a desire to avoid post-operative immobilization. Barriers included the pre-operative testing, cost and inconvenience of travel for surgery, and understanding complex health information related to the procedure. While expectations matched descriptions of outcomes among participants and were generally positive, caregivers expressed disappointment. The long time interval for gains in function to be realized and relatively incremental gains achieved were frustrating to all.

CONCLUSIONS

People with cervical spinal cord injury and their caregivers need more information about options to restore function and about realistic range of improvements with treatment. Further work to mitigate barriers and develop health information materials around nerve transfer surgery may improve medical decision making around and appropriate use of this newer treatment option.IMPLICATIONS FOR REHABILITATIONNerve transfer surgery is a novel and acceptable means of improving upper extremity function in the setting of cervical spinal cord injury.People with cervical spinal cord injury and their caregivers need information about options to restore hand and arm function and mitigation of barriers around these treatment options.

Comparative study of single and dual nerve transfers for repairing shoulder abduction

OBJECTIVE

The purpose of this study was to compare the effects of single and dual nerve transfer for the repair of shoulder abduction in patients with upper or upper and middle trunk root avulsion.

METHODS

We carried out a retrospective analysis of 20 patients with C5-C6 or C5-C7 root avulsion treated by nerve transfer in our hospital. The patients were divided into two groups according to the different operation methods. In group A, ten patients had transferred the spinal accessory nerve to the suprascapular nerve. Ten patients in group B underwent dual nerve transfer to reconstruct shoulder abduction, including the spinal accessory nerve transfer to the suprascapular nerve and two intercostal nerves or the long head of triceps nerve branch transfer to the anterior branch of the axillary nerve. There was no difference in age, preoperative interval, follow-up time, and injury type between the two groups. We used shoulder abduction strength, shoulder abduction angle, and Samardzic's shoulder joint evaluation standard as the postoperative evaluation index. Shoulder abductor muscle strength equals or above M3 was considered to be an effective recovery.

RESULTS

Of the 20 cases, 15 obtained equals or more M3 of shoulder abduction strength, and the overall effective rate was 75%. The effective rate of shoulder abduction power in group A was 60% (6/10) while group B was 90% (9/10); however, the difference was not statistically significant (p > 0.05). The average shoulder abduction angle was 55° (SD = 19.29) in group A and 77° (SD = 20.44) in group B; the angle was significantly better in group B than that in group A (p < 0.05). Based on Samardzic's standard, the excellent and good rate of group A was 90% and in group B was 50%. The difference was statistically significant (p < 0.05).

CONCLUSION

For patients with nerve root avulsion of C5-C6 or C5-C7, repairing suprascapular nerve and axillary nerve at the same time is more effective than repairing suprascapular nerve alone in terms of shoulder abduction angle and excellent rate of functional recovery of the shoulder joint. Therefore, we recommend the repair of the suprascapular nerve and the axillary nerve simultaneously if conditions permit.

Novel Uses of Nerve Transfers

Nerve transfer surgery involves using a working, functional nerve with an expendable or duplicated function as a donor to supply axons and restore function to an injured recipient nerve. Nerve transfers were originally popularized for the restoration of motor function in patients with peripheral nerve injuries. However, more recently, novel uses of nerve transfers have been described, including nerve transfers for sensory reinnervation, nerve transfers for spinal cord injury and stroke patients, supercharge end-to-side nerve transfers, and targeted muscle reinnervation for the prevention and treatment of postamputation neuroma pain. The uses for nerve transfers and the patient populations that can benefit from nerve transfer surgery continue to expand. Awareness about these novel uses of nerve transfers among the medical community is important in order to facilitate evaluation and treatment of these patients by peripheral nerve specialists. A lack of knowledge of these techniques continues to be a major barrier to more widespread implementation.

Double Motor Nerve Transfer for All Finger Flexion in Cervical Spinal Cord Injury: An Anatomical Study and a Clinical Report

PURPOSE

To explore the feasibility of restoring all finger flexion after a cervical spinal cord injury.

METHODS

Double nerve transfer was conducted in 22 cadaver upper extremities. Donor nerves were the brachialis branch of the musculocutaneous nerve and the extensor carpi radialis brevis (ECRB) branches of the radial nerve. Recipient nerves were the anterior interosseous nerve (AIN) and the flexor digitorum profundus (FDP) branch of ulnar nerve (ulnar-FDP). Nerve transfers were evaluated on 3 parameters: surgical feasibility, donor-to-recipient axon count ratio, and distance from the coaptation site to the muscle entry of recipient nerve. A complete C6 spinal cord injury reconstruction was accomplished in a patient using a double nerve transfer of ECRB to ulnar-FDP and brachialis to AIN.

RESULTS

In the cadaver study, nerve transfers from ECRB to AIN, brachialis to AIN, and ECRB to ulnar-FDP were all feasible. The transfer from the brachialis to ulnar-FDP was not possible. Mean myelinated axon counts of AIN, brachialis, ulnar-FDP, and ECRB were 2,903 ± 1049, 1,497 ± 606, 753 ± 364, and 567 ± 175, respectively. The donor-to-recipient axon count ratios of ECRB to AIN, brachialis to AIN, and ECRB to ulnar-FDP were 0.24 ± 0.15, 0.55 ± 0.38, and 0.98 ± 0.60, respectively. The distance from coaptation of the ECRB to the ulnar-FDP muscle entry was shorter than for the other nerve transfers (54 ± 14.29 mm). At 18 months, there was restoration of flexion in all fingers and functional improvement from double nerve transfer of the brachialis to the AIN and the ECRB to the ulnar-FDP.

CONCLUSIONS

Restoration of all finger flexion may be feasible by the ECRB to ulnar-FDP and brachialis to AIN double nerve transfer.

CLINICAL RELEVANCE

Double nerve transfer can be used in C6-C7 spinal cord injury and patients with lower arm-type brachial plexus injury who have no finger flexion but have good brachialis and ECRB.

The Use of Nerve Transfers to Restore Upper Extremity Function in Cervical Spinal Cord Injury

BACKGROUND

Nerve transfer surgery to restore upper extremity function in cervical spinal cord injury (SCI) is novel and may transform treatment. Determining candidacy even years post-SCI is ill defined and deserves investigation.

OBJECTIVE

To develop a diagnostic algorithm, focusing on electrodiagnostic (EDX) studies, to determine eligibility for nerve transfer surgery.

DESIGN

Retrospective descriptive case series.

SETTING

Tertiary university-based institution.

PATIENTS

Individuals with cervical SCI (n = 45).

METHODS

The electronic medical records of people referred to the Plastic Surgery Multidisciplinary Upper Extremity Surgery in SCI clinic from 2010-2015 were reviewed. People were considered for nerve transfers to restore elbow extension or finger flexion and/or extension. Data including demographic, clinical evaluation, EDX results, surgery, and outcomes were collected and analyzed.

MAIN OUTCOME MEASUREMENTS

EDX data, including nerve conduction studies and electromyography, for bilateral upper extremities of each patient examined was used to assess for the presence of lower motor neuron injury, which would preclude late nerve transfer.

RESULTS

Based on our criteria and the results of EDX testing, a substantial number of patients presenting even years post-SCI were candidates for nerve transfers. Clinical outcome results are heterogeneous but promising and suggest that further refinement of eligibility, long-term follow-up, and standardized assessment will improve our understanding of the role of nerve transfer surgery to restore function in people with midcervical SCI.

CONCLUSIONS

Many patients living with SCI are candidates for nerve transfer surgery to restore upper extremity function. Although the ultimate efficacy of these surgeries is not yet determined, this study attempts to report the criteria we are using and may ultimately determine the timing for intervention and which transfers are most useful for this heterogeneous population.

LEVEL OF EVIDENCE

IV.

Nerve and Tendon Transfer Surgery in Cervical Spinal Cord Injury: Individualized Choices to Optimize Function

Background: Recent adaption of nerve transfer surgery to improve upper extremity function in cervical spinal cord injury (SCI) is an exciting development. Tendon transfer procedures are well established, reliable, and can significantly improve function. Despite this, few eligible surgical candidates in the United States undergo these restorative surgeries. Evidence Acquisition: The literature on these procedures was reviewed. Results: Options to improve function include surgery to restore elbow extension, wrist extension, and hand opening and closing function. Tendon transfers are reliable and well tolerated but require weeks of immobilization and limits on extremity use. The role of nerve transfers is still being established. Early results indicate variable return of meaningful function with less immobilization but longer periods (up to years) required to gain appreciable function. Conclusion: Nerve and tendon transfer surgery sacrifice an expendable donor to restore a missing and more critical function. These procedures are well described in hand surgery; are reliable, well tolerated, and covered by insurance; and should be part of the SCI rehabilitation discussion.

Morphology of Donor and Recipient Nerves Utilised in Nerve Transfers to Restore Upper Limb Function in Cervical Spinal Cord Injury

Loss of hand function after cervical spinal cord injury (SCI) impacts heavily on independence. Multiple nerve transfer surgery has been applied successfully after cervical SCI to restore critical arm and hand functions, and the outcome depends on nerve integrity. Nerve integrity is assessed indirectly using muscle strength testing and intramuscular electromyography, but these measures cannot show the manifestation that SCI has on the peripheral nerves. We directly assessed the morphology of nerves biopsied at the time of surgery, from three patients within 18 months post injury. Our objective was to document their morphologic features. Donor nerves included teres minor, posterior axillary, brachialis, extensor carpi radialis brevis and supinator. Recipient nerves included triceps, posterior interosseus (PIN) and anterior interosseus nerves (AIN). They were fixed in glutaraldehyde, processed and embedded in Araldite Epon for light microscopy. Eighty percent of nerves showed abnormalities. Most common were myelin thickening and folding, demyelination, inflammation and a reduction of large myelinated axon density. Others were a thickened perineurium, oedematous endoneurium and Renaut bodies. Significantly, very thinly myelinated axons and groups of unmyelinated axons were observed indicating regenerative efforts. Abnormalities exist in both donor and recipient nerves and they differ in appearance and aetiology. The abnormalities observed may be preventable or reversible.

Nerve transfer for sensory reconstruction of C8-T1 dermatomes in tetraplegia

OBJECTIVES

Absence of sensation in C8-T1 dermatome is a common finding in midcervical spinal cord injury. The goal was to restore sensation on the C8-T1 dermatomes by transferring sensory nerves with afferents on C5-C6 roots.

METHODS

A mean 10 months post spinal cord injury, we operated on 10 upper limbs from 5 tetraplegics averaging 23 years old. Cutaneous branches of the median nerve were transferred to the palm to the ulnar proper digital nerve of the little finger. In two patients, the lateral antebrachial cutaneous nerve was also transferred to the medial antebrachial cutaneous nerve.

RESULTS

At a mean 20 months after surgery, on the ulnar side of the hand and little finger, all patients were able to perceive 19.3 g Semmes-Weinstein monofilament pressure. Nociception was restored on the medial side of the elbow, forearm, and hand. Faulty location was a common finding, but not as a major complaint.

CONCLUSIONS

Sensory nerve transfers should be incorporated into the reconstruction of the upper limb in tetraplegics. © 2015 Wiley Periodicals, Inc. Microsurgery 36:637-641, 2016.

Nerve Transfers in Tetraplegia

Hand and upper extremity function is instrumental to basic activities of daily living and level of independence in cervical spinal cord injury (SCI). Nerve transfer surgery is a novel and alternate approach for restoring function in SCI. This article discusses the biologic basis of nerve transfers in SCI, patient evaluation, management, and surgical approaches. Although the application of this technique is not new; recent case reports and case series in the literature have increased interest in this field. The challenges are to improve function, achieve maximal gains in function, avoid complications, and to primum non nocere.

Nerve Transfers to Restore Upper Extremity Function in Cervical Spinal Cord Injury: Update and Preliminary Outcomes

BACKGROUND

Cervical spinal cord injury can result in profound loss of upper extremity function. Recent interest in the use of nerve transfers to restore volitional control is an exciting development in the care of these complex patients. In this article, the authors review preliminary results of nerve transfers in spinal cord injury.

METHODS

Review of the literature and the authors' cases series of 13 operations in nine spinal cord injury nerve transfer recipients was performed. Representative cases were reviewed to explore critical concepts and preliminary outcomes.

RESULTS

The nerve transfers used expendable donors (e.g., teres minor, deltoid, supinator, and brachialis) innervated above the level of the spinal cord injury to restore volitional control of missing function such as elbow extension, wrist extension, and/or hand function (posterior interosseous nerve or anterior interosseous nerve/finger flexors reinnervated). Results from the literature and the authors' patients (after a mean postsurgical follow-up of 12 months) indicate gains in function as assessed by both manual muscle testing and patients' self-reported outcomes measures.

CONCLUSIONS

Nerve transfers can provide an alternative and consistent means of reestablishing volitional control of upper extremity function in people with cervical level spinal cord injury. Early outcomes provide evidence of substantial improvements in self-reported function despite relatively subtle objective gains in isolated muscle strength. Further work to investigate the optimal timing and combination of nerve transfer operations, the combination of these with traditional treatments (tendon transfer and functional electrical stimulation), and measurement of outcomes is imperative for determining the precise role of these operations.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Review of Upper Extremity Nerve Transfer in Cervical Spinal Cord Injury

OBJECTIVE

 Several nerve transfers have now been successfully performed for upper limb reanimation in tetraplegia. This study was performed to review the use of nerve transfers for upper limb reanimation in tetraplegia.

METHODS

 Medline and Embase (1950 to February 11, 2015) were searched using a search strategy designed to include any studies that reported cases of nerve transfer in persons with cervical spinal cord injury (SCI).

RESULTS

 A total of 103 manuscripts were selected initially and full-text analysis produced 13 studies with extractable data. Of these manuscripts, 10 reported single cases and 3 reported case series. Eighty-nine nerve transfers have been performed in 57 males and 2 females with a mean age of 34 years. The mean SCI level was C6 (range: C5-7), time to surgery post-SCI was 19.9 months (range: 4.1-156 months), and follow-up time was 18.2 months (range: 3-60 months). All case reports recorded a Medical Research Council (MRC) score of 3 or 4 for recipient muscle power, but two early case series reported more variable results.

CONCLUSION

 This review documents the current status of nerve transfer surgery for upper limb reanimation in tetraplegia and summarizes the functional results in 59 cases with 89 nerve transfers performed, including 15 cases of double-nerve transfer and 1 case of triple-nerve transfer.

Nerve transfers for elbow and finger extension reconstruction in midcervical spinal cord injuries

OBJECT

The objective of this study was to report the results of elbow, thumb, and finger extension reconstruction via nerve transfer in midcervical spinal cord injuries.

METHODS

Thirteen upper limbs from 7 patients with tetraplegia, with an average age of 26 years, were operated on an average of 7 months after a spinal cord injury. The posterior division of the axillary nerve was used to reinnervate the triceps long and upper medial head motor branches in 9 upper limbs. Both the posterior division and the branch to the middle deltoid were used in 2 upper limbs, and the anterior division of the axillary nerve in the final 2 limbs. For thumb and finger extension reconstruction, the nerve to the supinator was transferred to the posterior interosseous nerve.

RESULTS

In 22 of the 27 recipient nerves, a peripheral type of palsy with muscle denervation was identified. At an average of 19 months follow-up, elbow strength scored M4 in 11 upper limbs and M3 in 2, according to the British Medical Research Council scale. Thumb extension scored M4 in 8 upper limbs and scored M3 in 4. Finger extension scored M4 in 12 hands. No donor-site deficits were reported or observed.

CONCLUSIONS

Nerve transfers are effective at restoring elbow, thumb, and finger extension in patients with a midcervical spinal cord injury, which occurs in the majority of patients with a peripheral type of palsy with muscle denervation in their upper limbs. Efforts should be made to perform operations in these patients within 12 months of injury.

Thoracodorsal nerve transfer for triceps reinnervation in partial brachial plexus injuries

PURPOSE

To report the clinical outcomes of thoracodorsal nerve (TDN) transfers to the triceps motor branches for elbow extension restoration in patients with partial brachial plexus injuries (BPI).

METHODS

Eight male patients of mean age 23 years and suffering from a partial BPI underwent direct coaptation of the TDN to the nerve of the upper medial and long heads of the triceps, an average 6 months after their accident.

RESULTS

Seven patients achieved M4 elbow extension strength and one patient M3, according to the BMRC scale, after a mean follow-up of 21 months.

DISCUSSION

Direct TDN transfer might be a valid surgical procedure for the restoration of elbow extension in patients with partial BPI.

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.

Single-stage surgery combining nerve and tendon transfers for bilateral upper limb reconstruction in a tetraplegic patient: case report

A 39-year-old tetraplegic patient had paralysis of elbow, thumb, and finger extension and thumb and finger flexion. We transferred axillary nerve branches to the triceps long and upper medial head motor branches, supinator motor branches to the posterior interosseous nerve, and brachioradialis tendon to the flexor pollicis longus and flexor superficialis of the index finger. Surgery was performed bilaterally 18 months after spinal cord injury. At 12 months after surgery, we performed bilateral distal radioulnar arthrodesis percutaneously. By 22 months postoperatively, we observed triceps strength scoring M3 bilaterally and full metacarpophalangeal joint extension scoring M4 bilaterally. The thumb span was 53 and 66 mm from the proximal index phalanx on the right and left sides, respectively. Pinch strength measured 1.5 kg on the left side and 2.0 kg on the right. Before surgery, the patient was incapable of grasping; after surgery, a useful grasp had been restored bilaterally.

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.

Posterior branch of the axillary nerve transfer to the lateral triceps branch for restoration of elbow extension: case report

We report a nerve transfer to the triceps using the posterior branch of the axillary nerve to restore elbow extension in an 18-year-old woman with a C7-T1 injury. Elbow extension strength improved from M0 to M4, whereas deltoid strength was minimally affected. Her Disabilities of the Arm, Shoulder and Hand score improved 14 points. This method may be considered for restoring triceps function in lower pattern brachial plexus injury.

Nerve transfer strategies for spinal cord injury

BACKGROUND

Spinal cord injury (SCI) is a devastating condition, which beleaguers its victims with long-term health issues. Nerve transfer is a feasible option for restoration of critical limb function in patients with SCI that potentially improves independence and quality of life.

METHODS

This article delineates the general principles of nerve transfer and its specific application pertinent to SCI. The available nerve transfer strategies are described based on the targeted limb function, mostly involving critical upper extremity function. The role of nerve transfer for paraplegia, diaphragm reanimation, and bladder reinnervation is also discussed.

RESULTS

Nerve transfer offers several advantages over the traditionally used tendon transfer.

CONCLUSIONS

Nerve transfer does not require prolonged immobilization and provides greater functional gain for a given transfer. Reconstruction of several facets of upper limb function potentially can be performed in a single stage. The merits of nerve transfer deserve further study to evaluate its value for spinal cord injury in humans.

The clinical practice of reconstructive neurosurgery

Surgical interventions to improve function following nervous system injury have been in development since the early 1900s. Only recently these have been assimilated into a coherent approach which can be applied to injuries of the brain, spinal cord and peripheral nerves. In addition to pharmacological and stimulation based interventions, surgical manipulation of the peripheral nerves and muscles of the extremity can offer functional enhancement for a variety of limb impairments. In order to plan an effective surgical intervention, neurophysiological assessment of the injury and residual motor control is essential. Effective implementation of these surgical interventions can enhance function and quality of life for many individuals whose activity has been limited as a result of nervous system injury.

Transfer of the Distal Terminal Motor Branch of the Extensor Carpi Radialis Brevis to the Nerve of the Flexor Pollicis Longus

BACKGROUND:

In tetraplegics, thumb and finger motion traditionally has been reconstructed via orthopedic procedures. Although rarely used, nerve transfers are a viable method for reconstruction in tetraplegia.

OBJECTIVE:

To investigate the anatomic feasibility of transferring the distal branch of the extensor carpi radialis brevis (ECRB) to the flexor pollicis longus (FPL) nerve and to report our first clinical case.

METHODS:

We studied the motor branch of the ECRB and FPL in 14 cadaveric upper limbs. Subsequently, a 24-year-old tetraplegic man with preserved motion in his shoulder, elbow, wrist, and finger extension, but paralysis of thumb and finger flexion underwent surgery. Seven months after trauma, we transferred the brachialis muscle with a tendon graft to the flexor digitorum profundus. The distal nerve of the ECRB was transferred to the FPL nerve.

RESULTS:

The branch to the ECRB entered the muscle in its anterior and proximal third. After sending out a first collateral, the nerve runs for 2.4 cm alongside the muscle and bifurcates intramuscularly. A main branch from the anterior interosseous nerve, which entered the muscle 3 cm from its origin on the radius, innervated the FPL. The ECRB and FPL nerves had similar diameters (∼1 mm) and numbers of myelinated fibers (∼180). In our patient, 14 months after surgery, pinching and grasping were restored and measured 2 and 8 kg strength, respectively.

CONCLUSION:

Transfer of the ECRB distal branch to the FPL is a viable option to reconstruct thumb flexion.

Results and current approach for Brachial Plexus reconstruction

We review our experience treating 335 adult patients with supraclavicular brachial plexus injuries over a 7-year period at the University of Southern Santa Catarina, in Brazil. Patients were categorized into 8 groups, according to functional deficits and roots injured: C5-C6, C5-C7, C5-C8 (T1 Hand), C5-T1 (T2 Hand), C8-T1, C7-T1, C6-T1, and total palsy. To restore function, nerve grafts, nerve transfers, and tendon and muscle transfers were employed. Patients with either upper- or lower-type partial injuries experienced considerable functional return. In total palsies, if a root was available for grafting, 90% of patients had elbow flexion restored, whereas this rate dropped to 50% if no roots were grafted and only nerve transfers performed. Pain resolution should be the first priority, and root exploration and grafting helped to decrease or eliminate pain complaints within a short time of surgery.