Restoration of intrinsic hand function by superficial radial nerve: an anatomical study.

BACKGROUND: The contralateral seventh cervical (cC7) nerve root transfer represents a cornerstone technique in treating total brachial plexus avulsion injury. Traditional cC7 procedures employ the entire ulnar nerve as a graft, which inevitably compromises its restorative capacity. OBJECTIVE: Our cadaveric study seeks to assess this innovative approach aimed at preserving the motor branch of the ulnar nerve (MBUN). This new method aims to enable future repair stages, using the superficial radial nerve (SRN) as a bridge connecting cC7 and MBUN. METHODS: We undertook a comprehensive dissection of ten adult cadavers, generously provided by the Department of Anatomy, Histology, and Embryology at Fudan University, China. It allowed us to evaluate the feasibility of our proposed technique. For this study, we harvested only the dorsal and superficial branches of the ulnar nerve, as well as the SRN, to establish connections between the cC7 nerve and recipient nerves (both the median nerve and MBUN). We meticulously dissected the SRN and the motor and sensory branches of the ulnar nerve. Measurements were made from the reverse point of the SRN to the wrist flexion crease and the coaptation point of the SRN and MBUN. Additionally, we traced the MBUN from distal to proximal ends, recording its maximum length. We also measured the diameters of the nerve branches and tallied the number of axons. RESULTS: Our modified approach proved technically viable in all examined limbs. The distances from the reverse point of the SRN to the wrist flexion crease were 8.24 ± 1.80 cm and to the coaptation point were 6.60 ± 1.75 cm. The maximum length of the MBUN was 7.62 ± 1.03 cm. The average axon diameters in the MBUN and the anterior and posterior branches of the SRN were 1.88 ± 0.42 mm、1.56 ± 0.38 mm、2.02 ± 0.41 mm,respectively. The corresponding mean numbers of axons were 1426.60 ± 331.39 and 721.50 ± 138.22, and 741.90 ± 171.34, respectively. CONCLUSION: The SRN demonstrated the potential to be transferred to the MBUN without necessitating a nerve graft. A potential advantage of this modification is preserving the MBUN's recovery potential.

For how long do denervated muscles in children retain the ability to regenerate?: Restoration of elbow flexion and shoulder function by partial nerve transfer in a child with long-standing poliomyelitis-like paralysis.

BACKGROUND: In infant poliomyelitis or poliomyelitis-like paresis, there has been no means of treating residual paralysis and the policy has been to wait until an affected infant has grown sufficiently to enable tendon transfer or arthrodesis. However, recent reports have described relatively good results for early surgical intervention in the form of nerve transfer. METHODS: In a 4-year and 6-month-old child we transferred a partial ulnar nerve for elbow flexor reconstruction even 3 years and 10 months after the onset of poliomyelitis-like palsy and also transferred partial accessory and radial nerves for shoulder function restoration 6 months after the first operation. RESULTS: Elbow flexor restored M4 on the British Medical Research Council scale. The shoulder subluxation resolved, however, the strengths of the deltoid and infraspinatus remained almost M1. At the most recent clinical examination, the patient was 18 years old and the active range of motion of patient's left elbow was 0°-125°, and those of the whole shoulder girdle were abduction 35°, flexion 60°, extension 30° and external rotation 0°. CONCLUSIONS: The outcomes we achieved may support partial nerve transfer techniques as viable treatment options for persistent long-standing motor deficits following poliomyelitis-like palsy in children. However, we recommend performing partial nerve transfer as early as possible after recovery from flaccid paralysis and also use of nerves that derive from narrow spinal cord segments. After denervation, children's neuromuscular systems seem to have the ability to regenerate after a much longer period than has generally been believed. This speculation is based on only a single case report; thus, more experience is needed before this generalization can confidently be made.

Radial to axillary nerve transfer.

Axillary nerve injury is common after brachial plexus injuries, particularly with shoulder luxation. Nerve grafting is the traditional procedure for postganglionic injuries. Nerve transfer is emerging as a viable option particularly in late referrals. At the proximal arm the radial and axillary nerves lie close by. Sacrificing one of the triceps muscle nerve branches induces little negative consequences. Transferring the long head of the triceps nerve branch is a good option to recover axillary nerve function. The surgical technique is presented in a video, stressing the steps to achieve a successful result. The video can be found here: https://youtu.be/WbVbpMuPxIE .

Future Perspectives in the Management of Nerve Injuries.

AIM: The author presents a solicited "white paper" outlining her perspective on the role of nerve transfers in the management of nerve injuries. METHODS: PubMed/MEDLINE and EMBASE databases were evaluated to compare nerve graft and nerve transfer. An evaluation of the scientific literature by review of index articles was also performed to compare the number of overall clinical publications of nerve repair, nerve graft, and nerve transfer. Finally, a survey regarding the prevalence of nerve transfer surgery was administrated to the World Society of Reconstructive Microsurgery (WSRM) results. RESULTS: Both nerve graft and transfer can generate functional results and the relative success of graft versus transfer depended on the function to be restored and the specific transfers used. Beginning in the early 1990s, there has been a rapid increase from baseline of nerve transfer publications such that clinical nerve transfer publication now exceeds those of nerve repair or nerve graft. Sixty-two responses were received from WSRM membership. These surgeons reported their frequency of "usually or always using nerve transfers for repairing brachial plexus injuries as 68%, radial nerves as 27%, median as 25%, and ulnar as 33%. They reported using nerve transfers" sometimes for brachial plexus 18%, radial nerve 30%, median nerve 34%, ulnar nerve 35%. CONCLUSION: Taken together this evidence suggests that nerve transfers do offer an alternative technique along with tendon transfers, nerve repair, and nerve grafts.

Axon Counts Yield Multiple Options for Triceps Fascicular Nerve to Axillary Nerve Transfer.

PURPOSE: To evaluate the relative axonal match between potential donor and recipient nerves, so that maximal reinnervation potential may be reached with the least chance of donor site morbidity. METHODS: In 10 fresh-frozen cadaveric specimens, the main trunk and anterior, posterior, sensory and teres minor branches of the axillary nerve were identified, as were the radial nerve branches to the long, medial, and lateral heads of the triceps. The swing distances of the triceps fascicular nerve branches and the axillary nerve branches relative to the inferior border of the teres major muscle were recorded. Histomorphological analysis and axon counts were performed on sections of each branch. RESULTS: The median number of axons in the main axillary trunk was 7,887, with 4,052, 1,242, and 1,161 axons in the anterior, posterior, and teres minor branches, respectively. All specimens had a single long head triceps branch (median, 2,302 axons), a range of 1 to 3 branches to the medial head of the triceps (composite axon count, 2,198 axons), and 1 to 3 branches to the lateral head of the triceps (composite average, 1,462 axons). The medial and lateral head branches had sufficient swing distance to reach the anterior branch of the axillary nerve in all 10 specimens, with only 4 specimens having adequate long head branch swing distances. CONCLUSIONS: It is anatomically feasible to transfer multiple branches of the radial nerve supplying the medial, lateral, and sometimes, long head of the triceps to all branches of the axillary nerve in an attempt to reinnervate the deltoid and teres minor muscles. CLINICAL RELEVANCE: Understanding the axon counts of the different possible transfer combinations will improve operative flexibility and enable peripheral nerve surgeons to reinnervate for both abduction and external rotation with the highest donor/recipient axon count ratios.

Surgical Algorithm and Results of Isolated Traumatic Axillary Nerve Injuries.

BACKGROUND: Axillary nerve injuries are common and typically occur during high-energy, traumatic events. The purpose of this study is to propose a treatment algorithm for acute isolated axillary nerve injuries and report the outcomes of surgically treated patients. METHODS: A retrospective review identified 14 patients surgically treated for an isolated axillary nerve injury. Axillary nerve neurolysis was performed for all patients, and a triceps branch of the radial nerve was transferred to the axillary nerve in patients without evidence of deltoid function following intraoperative axillary nerve stimulation. Four patients were treated with neurolysis alone and 10 patients received a transfer. Pre- and postoperative deltoid strength, shoulder abduction, and the Disabilities of the Arm, Shoulder, and Hand (DASH) outcome score were evaluated. RESULTS: At most recent follow-up, both the neurolysis and nerve transfer groups had significant improvement in deltoid strength, with 86% achieving M4 or greater. Shoulder abduction improved from a mean of 63 to 127 degrees. This difference was significant in the nerve transfer group and when all patients were analyzed together. DASH scores significantly improved from a mean of 47 to 34 when all patients were analyzed together. No patients experienced a decrease in elbow extension strength following nerve transfer. CONCLUSIONS: In patients with preserved triceps strength, a triceps branch of the radial nerve can be coapted directly to the axillary nerve in the absence of deltoid contraction following electrical stimulation. Functional improvements were seen in patients treated with neurolysis alone and in combination with nerve transfer, supporting the use of intraoperative axillary nerve stimulation to guide treatment.

Transfer of a Terminal Motor Branch Nerve to the Flexor Carpi Ulnaris for Triceps Reinnervation: Anatomical Study and Clinical Cases.

PURPOSE: To analyze the anatomical feasibility of transferring a motor branch nerve to the flexor carpi ulnaris (FCU) to the triceps upper medial head motor branch (UMHM) and to report the resultant outcome of the restoration of elbow extension in 5 patients with extensive brachial plexus injury. METHODS: The ulnar and radial nerves were dissected in 10 cadavers. We measured the length and diameter of the branches to the FCU and the UMHM branch and counted the axons. Then, 5 male patients, mean age 30 years, underwent FCU nerve branch transfer for reconstruction of elbow extension. Elbow flexion was restored via a median nerve branch to biceps transfer. RESULTS: Mean UMHM nerve length and diameter were 86 and 1.5 mm, respectively. Mean number of branches to the FCU muscle was 2.9. Mean FCU nerve length and diameter were 50 and 1.0 mm, respectively. Mean number of myelinated fibers was 818 and 743 for the UMHM and the longest branch to the FCU, respectively. Coaptation between nerves was possible without tension. All patients recovered functional active elbow extension at a mean follow-up of 19 months with a British Medical Research Council score of M4. After surgery, all patients retained a functional FCU with a British Medical Research Council score of M4. CONCLUSIONS: Nonselective ulnar nerve fascicles at the root of the limb might not be adequate to restore elbow extension when combined with a median nerve branch transfer for elbow flexion. A selective distal ulnar motor fascicle such as a FCU motor branch could be harvested and connected to a triceps branch to restore elbow extension. Such a nerve transfer would also allow for later transfer of the still functional FCU tendon to the digital extensors. CLINICAL RELEVANCE: For patients with extensive brachial plexus injury and a preserved medial cord, transferring a motor branch nerve to the FCU is an effective technique for the reconstruction of elbow extension. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Direct radial to ulnar nerve transfer to restore intrinsic muscle function in combined proximal median and ulnar nerve injury: case report and surgical technique.

A distal median to ulnar nerve transfer for timely restoration of critical intrinsic muscle function is possible in isolated ulnar nerve injuries but not for combined ulnar and median nerve injuries. We used a distal nerve transfer to restore ulnar intrinsic function in the case of a proximal combined median and ulnar nerve injury. Transfer of the nonessential radial nerve branches to the abductor pollicis longus, extensor pollicis brevis, and extensor indicis proprius to the motor branch of the ulnar nerve was performed in a direct end-to-end fashion via an interosseous tunnel. This method safely and effectively restored intrinsic function before terminal muscle degeneration.

Trans-fracture transposition of the radial nerve during the open approach of humeral shaft fractures.

The radial nerve constitutes a major problem in humeral shaft fractures; it may be injured immediately or during closed reduction or open reduction and internal fixation with plate and screws. After fixation, the nerve always runs directly over the plate without any interposed structure. If a revision surgery is indicated, the nerve is at high risk as it is usually difficult to dissect from surrounding fibrotic scar tissue or callus formation. To avoid these complications, some authors reported transposition of the radial nerve through the fracture line. We present herein the surgical technique of the trans-fracture transposition of the radial nerve during open reduction and internal fixation of humeral shaft fractures, along with our preliminary results in 6 cases and a review of the literature.

The radio-radial nerve transfer for elbow extension restoration in C5 to C7 nerve root injury.

Extension of the elbow is required to oppose gravity; however, activation of the triceps brachii is frequently underestimated during the surgical planning for brachial plexus injuries. This report aims to describe a novel technique of distal nerve transfer designed for elbow extension reconstruction in patients sustaining a C5-C7 nerve root injury. We report a patient sustaining a brachial plexus injury with triceps palsy and preserved finger extension motion; after careful intraneural dissection of the radial nerve, a fascicle innervating the extensor digitorum communis muscle was sectioned, derouted and connected to a motor branch to the lateral head of the triceps. Eleven months after surgery, elbow extension strength scored MRC M4. No deficits on finger extension were observed.

Surgical technique of harvesting vascularized superficial radial nerve graft.

We describe our surgical technique for harvesting the free vascularized superficial radial nerve graft based on the radial artery and its venae comitantes. Anatomy and preoperative preparation are also presented, as well as the indications and some contraindications.

Combined Radial to Axillary and Spinal Accessory Nerve (SAN) to Suprascapular Nerve (SSN) Transfers May Confer Superior Shoulder Abduction Compared with Single SA to SSN Transfer.

BACKGROUND: The restoration of shoulder function after brachial plexus injury is a high priority. Shoulder abduction and stabilization can be achieved by nerve transfer procedures including spinal accessory nerve (SAN) to suprascapular nerve (SSN) and radial to axillary nerve transfer. The objective of this study is to compare functional outcomes after SAN to SSN transfer versus the combined radial to axillary and SA to SSN transfer. METHODS: This retrospective chart review included 14 consecutive patients with brachial plexus injury who underwent SAN to SSN transfer, 4 of whom had both SA to SSN and radial to axillary nerve transfer. RESULTS: SAN to SSN transfer achieved successful shoulder abduction (≥M3) in 64.3% of this cohort (9/14). During the long-term follow-up, patients achieved an average increase of 67.5° in shoulder abduction. There was no association between motor recovery and time from injury to surgery, age, body mass index (BMI), sex, or smoking status. The 4 patients who had SAN to SSN combined with radial to axillary nerve transfer demonstrated a statistically significant increase in the range of abduction (median, 90° vs. 42.5°, respectively; P = 0.022) compared with those who had SAN to SSN transfer alone; however, the difference in Medical Research Council (MRC) grades (MRC > M3) did not reach statistical significance (P = 0.07). CONCLUSIONS: Patients with brachial plexus injury and an intact C7 root could benefit from radial to axillary transfer in addition to SAN to SSN transfer. There was no association between recovery of shoulder abduction and time interval from injury to surgery, age, sex, smoking, and BMI.

Arterialized Posterior Interosseous Nerve Graft for Digital Neuroma.

Painful neuromas are not uncommon following nerve injury, and are especially bothersome in the hand, with severe cases resulting in significant disability. Outcomes of neuroma surgery are unpredictable regardless of technique. It is recognized that optimal soft tissue environment influences nerve healing more than the specific nerve graft technique, and it is in this context, we present a novel technique of transferring a posterior interosseous nerve graft along with vascularized synovial and fat tissue based on a branch of the posterior interosseous artery to provide healthy soft tissue for nerve healing of neuroma in continuity about the hand and digits.

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

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

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

BACKGROUND: The most commonly performed nerve transfers in upper trunk (UT) or partial brachial plexus injuries (BPIs) include the spinal accessory nerve to suprascapular nerve, Oberlin, and, lately, radial nerve (RN) (branch to triceps) to axillary nerve (AN) transfers. Routinely, the former 3 procedures are performed through an anterior approach (supraclavicular plus infraclavicular), while the triceps branch of the RN-AN transfer has been performed through a posterior approach with the patient in either the prone or semilateral position, which requires a separate incision in the posterior arm. The aim of the present study was to report the outcomes for 4 cases of quadruple nerve transfers performed for UT BPI using an all-anterior approach. METHODS: The functional outcomes of 4 consecutive cases of UT BPI treated using an all-anterior approach were analyzed in terms of improvement in motor power and range of motion at the shoulder and elbow joints. RESULTS: The mean age was 27.5 years (range, 16-40). All had sustained injuries from road traffic accidents. The mean injury to surgery interval was 4.5 months (range, 3-6). Of the 4 patients, 2 each had pre- and postganglionic injuries. All 4 patients had 0 of M0 power in shoulder abduction and external rotation, and elbow flexion. At a mean follow-up of 28.6 months, the average shoulder abduction was 157°, with an average of 82° of external rotation. The mean elbow flexion was 104°. CONCLUSIONS: This technique appears to be feasible, with good-to-excellent outcomes achieved without requiring a separate posterior arm incision for the RN-AN transfer.

"In Situ Vascular Nerve Graft" for Restoration of Intrinsic Hand Function: An Anatomical Study.

BACKGROUND: In combined high median and ulnar nerve injury, transfer of the posterior interosseous nerve branches to the motor branch of the ulnar nerve (MUN) is previously described in order to restore intrinsic hand function. In this operation a segment of sural nerve graft is required to close the gap between the donor and recipient nerves. However the thenar muscles are not innervated by this nerve transfer. The aim of the present study was to evaluate whether the superficial radial nerve (SRN) can be used as an "in situ vascular nerve graft" to connect the donor nerves to the MUN and the motor branch of median nerve (MMN) at the same time in order to address all denervated intrinsic and thenar muscles. METHODS: Twenty fresh male cadavers were dissected in order to evaluate the feasibility of this modification of technique. The size of nerve branches, the number of axons and the tension at repair site were evaluated. RESULTS: This nerve transfer was technically feasible in all specimens. There was no significant size mismatch between the donor and recipient nerves Conclusions: The possible advantages of this modification include innervation of both median and ulnar nerve innervated intrinsic muscles, preservation of vascularity of the nerve graft which might accelerate the nerve regeneration, avoidance of leg incision and therefore the possibility of performing surgery under regional instead of general anesthesia. Briefly, this novel technique is a viable option which can be used instead of conventional nerve graft in some brachial plexus or combined high median and ulnar nerve injuries when restoration of intrinsic hand function by transfer of posterior interosseous nerve branches is attempted.