Nerve transfer to the triceps after brachial plexus injury: report of four cases

The 2-by-2 Inch "Key Window" in the Upper Extremity: An Anatomical Appraisal of the Accessibility and Proximity of the Major Nerves and Vessels

BACKGROUND

The brachial plexus is a network of nerves located between the neck and axilla, which receives input from C5-T1. Distally, the nerves and blood vessels that supply the arm and forearm form a medial neurovascular bundle. The purpose of this study was to illustrate that a peripheral nerve dissection via a 2 × 2 inch window would allow for identification and isolation of the major nerves and blood vessels that supply the arm and forearm.

METHODS

A right side formalin-fixed latex-injected cadaveric arm was transected at the proximal part of the axillary fold and included the scapular attachments. Step-by-step anatomical dissection was carried out and documented with three-dimensional digital imaging.

RESULTS

A 2 × 2 inch window centered 2 inches distal to the axillary fold on the medial surface of the arm enabled access to the major neurovascular structures of the arm and forearm: the median nerve, ulnar nerve, medial antebrachial cutaneous nerve, radial nerve and triceps motor branches, musculocutaneous nerve and its biceps and brachialis branches and lateral antebrachial cutaneous nerve, basilic vein and brachial artery and vein, and profunda brachii artery.

CONCLUSIONS

Our study demonstrates that the majority of the neurovascular supply in the arm and forearm can be accessed through a 2 × 2 inch area in the medial arm. Although this "key window" may not be entirely utilized in the operative setting, our comprehensive didactic description of peripheral nerve dissection in the cadaver laboratory can help in safer identification of complex anatomy encountered during surgical procedures.

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.

Histologic Analysis of Sensory and Motor Axons in Branches of the Human Brachial Plexus

BACKGROUND

The topographic distribution through histologic analysis of motor and sensory axons within peripheral nerves at the brachial plexus level is not clearly defined, as there has previously been little need to appreciate this microanatomy. A desire to better understand the topography of fascicle groups developed with the introduction of targeted muscle reinnervation.

METHODS

Fourteen bilateral brachial plexus specimens from seven fresh human cadavers were harvested at the time of organ donation, and immunofluorescent staining of motor and sensory nerves with choline acetyltransferase and Neurofilament 200 was performed to determine whether a consistent somatotopic orientation exists at the brachial plexus level.

RESULTS

There was significant variability in the number of fascicles at the level of the brachial plexus. Qualitative analysis of choline acetyltransferase staining demonstrated that although motor axons tended to be grouped in clusters, there were high degrees of variability in somatotopic orientation across specimens. The radial nerve demonstrated the highest number of total myelinated axons, whereas the median nerve exhibited the greatest number of motor axons. The ulnar nerve contained only 13 percent motor axons, which was significantly lower than the median, radial, and musculocutaneous nerves.

CONCLUSIONS

There was no consistent somatotopic organization of motor and sensory axons of the mixed major nerves of the arm just distal to the brachial plexus, but clustering of motor axons may facilitate the splitting of nerves into primarily "motor" and "sensory" fascicles.

Combined flexor carpi ulnaris and flexor carpi radialis transfer for restoring elbow function after brachial plexus injury

The result of combined agonist and antagonist muscle innervation in traumatic brachial plexus injury through the intraplexal fascicle nerve transfers with the same donor function has not yet been reported. We describe a patient with a C5-C7 traumatic brachial plexus injury who had a combined transfer of the flexor carpi radialis (FCR) fascicle to the musculocutaneous nerve and the flexor carpi ulnaris (FCU) fascicle to the radial nerve of the triceps. The patient returned for his follow-up visit 2 years after his surgery. The muscle strengths of his triceps and biceps were Medical Research Council grade 2 and 0, respectively. Compared with his uninjured side, his grip strength was 9.8%, and his pinch strength was 14.2%. Our case report provides insights on result of combined agonist and antagonist muscle innervation through combining the motor fascicle of the FCR and FCU to restore the elbow flexor and extensor. The result may not be promising.

The Surgical Management of Nerve Gaps: Present and Future

Peripheral nerve injuries can result in significant morbidity, including motor and/or sensory loss, which can affect significantly the life of the patient. Nowadays, the gold standard for the treatment of nerve section is end-to-end neurorrhaphy. Unfortunately, in some cases, there is segmental loss of the nerve trunk. Nerve mobilization allows primary repair of the sectioned nerve by end-to-end neurorrhaphy if the gap is less than 1 cm. When the nerve gap exceeds 1 cm, autologous nerve grafting is the gold standard of treatment. To overcome the limited availability and the donor site morbidity, other techniques have been used: vascularized nerve grafts, cellular and acellular allografts, nerve conduits, nerve transfers, and end-to-side neurorrhaphy. The purpose of this review is to present an overview of the literature on the applications of these techniques in peripheral nerve repair. Furthermore, preoperative evaluation, timing of repair, and future perspectives are also discussed.

Results of nerve grafting in radial nerve injuries occurring proximal to the humerus, including those within the posterior cord

OBJECTIVE Results of radial nerve grafting are largely unknown for lesions of the radial nerve that occur proximal to the humerus, including those within the posterior cord. METHODS The authors describe 13 patients with proximal radial nerve injuries who were surgically treated and then followed for at least 24 months. The patients' average age was 26 years and the average time between accident and surgery was 6 months. Sural nerve graft length averaged 12 cm. Recovery was scored according to the British Medical Research Council (BMRC) scale, which ranges from M0 to M5 (normal muscle strength). RESULTS After grafting, all 7 patients with an elbow extension palsy recovered elbow extension, scoring M4. Six of the 13 recovered M4 wrist extension, 6 had M3, and 1 had M2. Thumb and finger extension was scored M4 in 3 patients, M3 in 2, M2 in 2, and M0 in 6. CONCLUSIONS The authors consider levels of strength of M4 for elbow and wrist extension and M3 for thumb and finger extension to be good results. Based on these criteria, overall good results were obtained in only 5 of the 13 patients. In proximal radial nerve lesions, the authors now advocate combining nerve grafts with nerve or tendon transfers to reconstruct wrist, thumb, and finger extension.

The zonal pattern of arterial supply to the brachial plexus and its clinical significance

PURPOSE

To provide the anatomical basis of blood supply of brachial plexus for the clinical microsurgical treatment of brachial plexus injury.

METHODS

Thirteen adult anticorrosive cadaveric specimens (8 males, 5 females) were dissected in this study. 3 fresh cases (2 males, 1 female) were used to observe the zonal pattern of arteries supplying brachial plexus, and 10 cases (6 males, 4 females) were used to observe the source and distribution of the brachial plexus arteries under microscope.

RESULTS

The brachial plexus is supplied by branches of the subclavian-axillary axis (SAA), and these branches anastomose each other. According to distribution feature, blood supply of the brachial plexus could be divided into three zones. The first zone was from the nerve roots of intervertebral foramina to its proximal trunks, which was supplied by the vertebral artery and the deep cervical artery. The second zone was from the distal nerve trunks of the brachial plexus, encompassing the divisions to its proximal cords, which was supplied by direct branches of the subclavian artery or by branches originating from the dorsal scapular artery. The third zone was from the distal portion of the cords to terminal branches of the brachial plexus, which was supplied by direct branches of the axillary artery.

CONCLUSIONS

The zonal pattern of arterial supply to the brachial plexus is a systematic and comprehensive modality to improve anatomical basis for the clinical microsurgical treatment for brachial plexus injury.

Outcomes of Transferring a Healthy Motor Fascicle From the Radial Nerve to a Branch for the Triceps to Recover Elbow Extension in Partial Brachial Plexus Palsy

BACKGROUND: Triceps reinnervation is an important objective to pursue when repairing the brachial plexus for cases with upper roots injuries, and a number of different techniques have been developed in order to restore elbow extension in such cases.

OBJECTIVE: To demonstrate the surgical outcomes associated with the technique of transferring a single healthy motor fascicle from the radial nerve of the affected arm to a branch innervating 1 of the 3 heads of the triceps.

METHODS: A retrospective study of 13 adult patients sustaining an upper trunk syndrome associated with total elbow extension palsy who underwent the proposed technique as part of the surgical planning for reconstruction of the brachial plexus.

RESULTS: Outcomes scored as M4 for elbow extension were noted in 9 cases (70%), M3 in 3 (23%), and M1 in 1 subject (7%). No patient considered the postoperative strength for carpal or finger extension as impaired. There were no differences in outcomes by using a fascicle activating carpal or finger extension as donor, as well as regarding the use of the branch to the medial or lateral head of the triceps as the recipient.

CONCLUSION: The technique of transferring a healthy motor fascicle from the radial nerve of the affected side to one of its nonfunctional motor branches to the triceps is an effective and safe procedure for recovering elbow extension function in patients sustaining partial injuries of the brachial plexus.

Nerve Transfers to Restore Elbow Function

The purpose of this article is to provide an overview of the various nerve transfer options for restoration of elbow function. This article describes nerve transfer strategies for elbow flexion and extension including the indications, limitations, and expected outcomes based on current literature.

Vascularized Thoracodorsal to Suprascapular Nerve Transfer, a Novel Technique to Restore Shoulder Function in Partial Brachial Plexopathy

We describe the clinical outcome of a novel nerve transfer to restore active shoulder motion in upper brachial plexus injury. The thoracodorsal nerve (TDN) was successfully used as a vascularized donor nerve to neurotize to the suprascapular nerve (SSN) in a patient with limited donor nerve availability. At 4 years follow-up, he had regained useful external rotation of the injured limb, with no significant donor site morbidity. Shoulder abduction return was less impressive, however, and reasons for this are discussed. We provide a comprehensive review of the literature on this topic and a subsequent discussion on the details of this novel technique. This is the first reported case of TDN to SSN transfer, and also the first reported case of a vascularized TDN transfer in the English language literature. We advocate direct thoracodorsal to SSN transfer as a valid surgical option for the restoration of shoulder function in patients with partial brachial plexus avulsion, when conventional nerve donors are unavailable.

Results of nerve grafting in radial nerve injuries occurring proximal to the humerus, including those within the posterior cord

OBJECT

Results of radial nerve grafting are largely unknown for lesions of the radial nerve that occur proximal to the humerus, including those within the posterior cord.

METHODS

The authors describe 13 patients with proximal radial nerve injuries who were surgically treated and then followed for at least 24 months. The patients’ average age was 26 years and the average time between accident and surgery was 6 months. Sural nerve graft length averaged 12 cm. Recovery was scored according to the British Medical Research Council (BMRC) scale, which ranges from M0 to M5 (normal muscle strength).

RESULTS

After grafting, all 7 patients with an elbow extension palsy recovered elbow extension, scoring M4. Six of the 13 recovered M4 wrist extension, 6 had M3, and 1 had M2. Thumb and finger extension was scored M4 in 3 patients, M3 in 2, M2 in 2, and M0 in 6.

CONCLUSIONS

The authors consider levels of strength of M4 for elbow and wrist extension and M3 for thumb and finger extension to be good results. Based on these criteria, overall good results were obtained in only 5 of the 13 patients. In proximal radial nerve lesions, the authors now advocate combining nerve grafts with nerve or tendon transfers to reconstruct wrist, thumb, and finger extension.

Motor Nerve Transfers

Brachial plexus and peripheral nerve injuries are exceedingly common. Traditional nerve grafting reconstruction strategies and techniques have not changed significantly over the last 3 decades. Increased experience and wider adoption of nerve transfers as part of the reconstructive strategy have resulted in a marked improvement in clinical outcomes. We review the options, outcomes, and indications for nerve transfers to treat brachial plexus and upper- and lower-extremity peripheral nerve injuries, and we explore the increasing use of nerve transfers for facial nerve and spinal cord injuries. Each section provides an overview of donor and recipient options for nerve transfer and of the relevant anatomy specific to the desired function.

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.

Motor and sensory nerve transfers in the forearm and hand

BACKGROUND

Peripheral nerve injury is a significant problem affecting more than 1 million people around the world each year and poses major challenges to the plastic and reconstructive surgeon. For high upper extremity nerve injuries, distal muscle reinnervation and functional outcomes are generally poor. Tendon transfer has been the traditional reconstructive option in these cases to restore hand function. More recently, nerve transfers have been described in the forearm and hand to recover hand and wrist function and critical sensation.

METHODS

This article reviews the surgical principles, donor nerve options, indications, and outcomes of distal nerve transfers for high upper extremity nerve injuries.

RESULTS

The functional results of nerve transfers to date have been comparable to tendon transfers. The primary advantage is the potential for individual finger motion from a donor nerve with singular function. The disadvantage is the longer recovery time required for muscle reinnervation.

CONCLUSIONS

Nerve transfers are a viable option for peripheral nerve injuries distal to the brachial plexus. The choice of management will depend on the patient's individual goals and priorities in terms of the need or desire for individual finger movement and the length of the recovery period.

Advances in nerve transfer surgery

Peripheral nerve injuries are devastating injuries and can result in physical impairments, poor functional outcomes and high levels of disability. Advances in our understanding of peripheral nerve regeneration and nerve topography have lead to the development of nerve transfers to restore function. Over the past two decades, nerve transfers have been performed and modified. With the advancements in surgical management and recognition of importance of cortical plasticity, motor-reeducation and perioperative rehabilitation, nerve transfers are producing improved functional outcomes in patients with nerve injuries. This manuscript explores the recent literature as it relates to current nerve transfer techniques and advances in post-operative rehabilitation protocols, with a focus on indications, techniques and outcomes.

Results of surgical techniques for re-innervation of the triceps as additional procedures for patients with upper root injuries

Patients with injuries restricted to the upper and middle trunks of the brachial plexus may obtain recovery of elbow extension via the lower trunk, which makes it difficult to assess the real effect of interventions to restore the triceps function in such cases. This study aimed to determine the impact of surgical strategies for re-innervation of the triceps in individuals with partial injuries of the brachial plexus. Patients were divided into two groups. Group 1 consisted of 21 participants in whom the surgery included one technique for re-innervation of elbow extension. In this group, six different extra- or intra-plexal donors were targeted to one of the motor branches of the triceps muscle. Group 2 was composed of 24 controls in which the reconstruction did not include any intervention for recovering triceps function. The individuals who underwent intervention for re-innervation of the triceps obtained significantly better outcomes for elbow extension than the controls.

Transfer of median and ulnar nerve fascicles for lesions of the posterior cord in infraclavicular brachial plexus injury: report of 2 cases

In infraclavicular lesions of brachial plexus, severe lesions of the posterior cord often occur when medial and lateral cord function is preserved to a greater or lesser extent. In these cases, shoulder function may be preserved by activity of the muscles innervated by the suprascapular nerve, but complete paralysis exists in the deltoid, triceps, and brachioradialis, and all wrist and finger extensors. Classical reconstruction procedures consist of nerve grafts, but their results in adults are disappointing. We report an approach transferring: (1) an ulnar nerve fascicle to the motor branch of the long portion of the triceps brachii muscle, (2) a median nerve branch from the pronator teres to the motor branch of the extensor carpi radialis longus, and (3) a median nerve branch from the flexor carpi radialis to the posterior interosseous nerve. We describe the procedure and report 2 clinical cases showing the effectiveness of this technique for restoring extension of the elbow, wrist, and fingers in the common infraclavicular lesions of the brachial plexus affecting the posterior cord.

Axillary nerve repair by fascicle transfer from the ulnar or median nerve in upper brachial plexus palsy

Object

Nerve repair using motor fascicles of a different nerve was first described for the repair of elbow flexion (Oberlin technique). In this paper, the authors describe their experience with a similar method for axillary nerve reconstruction in cases of upper brachial plexus palsy.

Methods

Of 791 nerve reconstructions performed by the senior author (P.H.) between 1993 and 2011 in 441 patients with brachial plexus injury, 14 involved axillary nerve repair by fascicle transfer from the ulnar or median nerve. All 14 of these procedures were performed between 2007 and 2010. This technique was used only when there was a deficit of the thoracodorsal or long thoracic nerve, which are normally used as donors.

Results

Nine patients were followed up for 24 months or longer. Good recovery of deltoid muscle strength was seen in 7 (77.8%) of these 9 patients, and in 4 patients with less follow-up (14–23 months), for an overall success rate of 78.6%. The procedure was unsuccessful in 2 of the 9 patients with at least 24 months of follow-up. The first showed no signs of reinnervation of the axillary nerve by either clinical or electromyographic evaluation in 26 months of follow-up, and the second had Medical Research Council (MRC) Grade 2 strength in the deltoid muscle 36 months after the operation. The last of the group of 14 patients has had 12 months of follow-up and is showing progressive improvement of deltoid muscle function (MRC Grade 2).

Conclusions

The authors conclude that fascicle transfer from the ulnar or median nerve onto the axillary nerve is a safe and effective method for reconstruction of the axillary nerve in patients with upper brachial plexus injury.

Nerve reconstruction in the hand and upper extremity

In the management of traumatic peripheral nerve injuries, the severity or degree of injury dictates the decision making between surgical management versus conservative management and serial examination. This review explores some of the recent literature, specifically addressing recent basic science advances in end-to-side and reverse end-to-side recovery, Schwann cell migration, and neuropathic pain. The management of nerve gaps, including the use of nerve conduits and acellularized nerve allografts, is examined. Current commonly performed nerve transfers are detailed with focus on both motor and sensory nerve transfers, their indications, and a basic overview of selected surgical techniques.

Efficacy of Short-Term FK506 Administration on Accelerating Nerve Regeneration

Background. The slow rate of nerve regeneration following injury can cause extended muscle denervation, leading to irreversible muscle atrophy, fibrosis, and destruction of motor endplates. The immunosuppressant FK506 (tacrolimus) has been shown to accelerate the rate of nerve regeneration and functional recovery. However, the toxic and immunosuppressive properties of FK506 make it undesirable for long-term use. Objective. To take advantage of the regeneration-enhancing effects of FK506 but avoid the potential adverse effects of long-term administration, the current study evaluates and quantifies the efficacy of short-term FK506 treatment in rat models. Methods. Clinically relevant transection and graft models were evaluated, and walking track analysis (WTA) was used to evaluate functional recovery. FK506 was administered for 5 and 10 days post transection injury and 10 and 20 days post graft injury. Both groups involving a short course were compared with the continuous administration group. Results. In the transection model, FK506 was administered for 5 and 10 days postoperatively. WTA demonstrated that 10 days of FK506 administration was sufficient to reduce functional recovery time by 29% compared with negative controls. In the graft model, FK506 was administered for 10 and 20 days postoperatively. Short treatment courses of 10 and 20 days reduced recovery time by 15% and 21%, respectively, compared with negative controls. Analysis of blood–nerve barrier (BNB) integrity demonstrated that FK506 facilitated early reconstitution of the BNB. Conclusions. The results of this study indicate that short-term FK506 delivery following nerve injury imparts a significant therapeutic effect.

Evaluation of peripheral nerve regeneration via in vivo serial transcutaneous imaging using transgenic Thy1-YFP mice

This study uses the saphenous nerve crush model in Thy1-YFP mice and serial transcutaneous imaging to evaluate the rate of nerve regeneration under various FK-506 (tacrolimus) dosing regimens and in the presence of transgenic overexpression of glial cell line-derived neurotrophic factor (GDNF). Thy1-YFP transgenic mice received saphenous nerve crush and were monitored for axonal regeneration via transcutaneous imaging for 7 days. Group A received no FK-506. Groups B and C received FK-506 at 2 or 0.5 mg/kg/day, starting three days before injury (preload). Groups D and E received FK-506 at 2 or 0.5 mg/kg/day, starting on the day of injury. Group F consisted of double transgenic mice with central overexpression of GDNF by CNS astrocytes (GFAP-GDNF/Thy1-YFP). Length and rate of axonal regeneration were measured and calculated over time. Regardless of concentration, FK-506 preload (Groups B and C) improved length and rate of axonal outgrowth compared with controls (Group A) and no preload (Groups D and E). Surprisingly, central overexpression of GDNF (GFAP-GDNF) delayed and stunted axonal outgrowth. Saphenous nerve crush in Thy1-YFP mice represents a viable model for timely evaluation of therapeutic strategies affecting the rate of nerve regeneration. FK-506 administered three days prior to injury accelerates axonal regeneration beyond injury conditioned regeneration alone and may serve as a reliable positive control for the model. GDNF overexpression in the CNS impedes early axonal outgrowth.