Functional recovery following an end to side neurorrhaphy of the accessory nerve to the suprascapular nerve: case report

Nerve Transfers-A Paradigm Shift in the Reconstructive Ladder

In this review, we present the current role of nerve transfers in the management of nerve injuries. The outcome of a literature review comparing the results of nerve graft versus nerve transfer and the experience of select surgical societies' members regarding experience and adoption of nerve transfer are reported. Nerve transfer publications have increased more than nerve graft or repair articles. The surgeon survey revealed an increase in nerve transfers and that more motor nerve transfers have been adopted into practice compared to sensory nerve transfers. The meta-analyses and systematic reviews of motor nerve transfers for shoulder and elbow function presented variable outcomes related to donor nerve selection. Comprehensive patient assessment is essential to evaluate the immediate functional needs and consider future reconstruction that may be necessary. Optimal outcome following nerve injury may involve a combination of different surgical options and more than one type of reconstruction. Nerve transfer is a logical extension of the paradigm shift from nerve repair and nerve graft and offers a new rung on the reconstruction ladder.

Nerve Transfers-A Paradigm Shift in the Reconstructive Ladder

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In this review, we present the current role of nerve transfers in the management of nerve injuries. The outcome of a literature review comparing the results of nerve graft versus nerve transfer and the experience of select surgical societies’ members regarding experience and adoption of nerve transfer are reported. Nerve transfer publications have increased more than nerve graft or repair articles. The surgeon survey revealed an increase in nerve transfers and that more motor nerve transfers have been adopted into practice compared to sensory nerve transfers. The meta-analyses and systematic reviews of motor nerve transfers for shoulder and elbow function presented variable outcomes related to donor nerve selection. Comprehensive patient assessment is essential to evaluate the immediate functional needs and consider future reconstruction that may be necessary. Optimal outcome following nerve injury may involve a combination of different surgical options and more than one type of reconstruction. Nerve transfer is a logical extension of the paradigm shift from nerve repair and nerve graft and offers a new rung on the reconstruction ladder.

Donor Distal, Recipient Proximal and Other Personal Perspectives on Nerve Transfers

This article presents a personal overview of nerve transfers and emphasizes the various factors that contribute to outcome following these surgeries. There is no "one result" for all nerve transfers. The results will vary depending on factors relating to the donor nerve and the recipient nerve, the degree of the surgical difficulty of the specific procedure, and issues relating to preoperative and postoperative rehabilitation. The general issues that influence all nerve injury and recovery, such as age of the patient, comorbidities, and time since injury, pertain to nerve transfers as well.

Neurite outgrowth on electrospun PLLA fibers is enhanced by exogenous electrical stimulation

OBJECTIVE

Both electrical stimuli (endogenous and exogenous) and topographical cues are instructive to axonal extension. This report, for the first time, investigated the relative dominance of directional topographical guidance cues and directional electrical cues to enhance and/or direct primary neurite extension. We hypothesized the combination of electrical stimulation with electrospun fiber topography would induce longer neurite extension from dorsal root ganglia neurons than the presence of electrical stimulation or aligned topography alone.

APPROACH

To test the hypothesis, neurite outgrowth was examined on laminin-coated poly-L-lactide films or electrospun fibers (2 µm in diameter) in the presence or absence of electrical stimulation. Immunostained neurons were semi-automatically traced using Neurolucida software and morphology was evaluated.

MAIN RESULTS

Neurite extension increased 74% on the aligned fibers compared to film controls. Stimulation alone increased outgrowth by 32% on films or fibers relative to unstimulated film controls. The co-presentation of topographical (fibers) with biophysical (electrical stimulation) cues resulted in a synergistic 126% increase in outgrowth relative to unstimulated film controls. Field polarity had no influence on the directionality of neurites, indicating topographical cues are responsible for guiding neurite extension.

SIGNIFICANCE

Both cues (electrical stimulation and fiber geometry) are modular in nature and can be synergistically applied in conjunction with other common methods in regenerative medicine such as controlled release of growth factors to further influence axonal growth in vivo. The combined application of electrical and aligned fiber topographical guidance cues described herein, if translated in vivo, could provide a more supportive environment for directed and robust axonal regeneration following peripheral nerve injury.

Supercharge nerve transfer to enhance motor recovery: a laboratory study

PURPOSE

To investigate the ability of a supercharge end-to-side (SETS) nerve transfer to augment the effect of regenerating native axons in an incomplete rodent sciatic nerve injury model.

METHODS

Fifty-four Lewis rats were randomized to 3 groups. The first group was an incomplete recovery model (IRM) of the tibial nerve complemented with an SETS transfer from the peroneal nerve (SETS-IRM). The IRM consisted of tibial nerve transection and immediate repair using a 10-mm fresh tibial isograft to provide some, but incomplete, nerve recovery. The 2 control groups were IRM alone and SETS alone. Nerve histomorphometry, electron microscopy, retrograde labeling, and muscle force testing were performed.

RESULTS

Histomorphometry of the distal tibial nerve showed significantly increased myelinated axonal counts in the SETS-IRM group compared with the IRM and SETS groups at 5 and 8 weeks. Retrograde labeling at 8 weeks confirmed increased motoneuron counts in the SETS-IRM group. Functional recovery at 8 weeks showed a significant increase in muscle-specific force in the SETS-IRM group compared with the IRM group.

CONCLUSIONS

An SETS transfer enhanced recovery from an incomplete nerve injury as determined by histomorphometry, motoneuron labeling within the spinal cord, and muscle force measurements.

CLINICAL RELEVANCE

An SETS distal nerve transfer may be useful in nerve injuries with incomplete regeneration such as proximal Sunderland II- or III-degree injuries, in which long regeneration distance yields prolonged time to muscle reinnervation and suboptimal functional recovery.

Side-to-side neurorrhaphy for high-level peripheral nerve injuries

Background

The results of peripheral nerve repair, especially for high-level peripheral nerve injuries, have been unsatisfactory. The method of side-to-side neurorrhaphy was developed in our laboratory from 1994 to 2002. This method involves suturing the injured nerve to a nearby donor nerve in a side-to-side manner. This study was performed to assess the clinical results of side-to-side neurorrhaphy in patients with high-level peripheral nerve injuries.

Methods

Twenty-five patients with various types of high-level peripheral nerve injuries who underwent side-to-side neurorrhaphy were studied. The British Medical Research Council (BMRC) scale was used to assess recovery of nerve function.

Results

Average follow-up duration was 3.2 years. Before surgery the patients had a nerve function of M0/S0 to M1/S1. After side-to-side neurorrhaphy, 7 patients had a score of M3/S4, 8 patients a score of M3/S3 and 10 patients a score of M2/S3. The total useful recovery rate (BMRC grade ≥3) was 60% for motor function and 100% for sensory function. Side-to-side neurorrhaphy did not result in any significant loss of donor nerve function. There was significant correlation between both the type of injury and the time interval between injury and surgery and motor nerve function. Age, gender and location of the injured nerve did not correlate with sensory or motor nerve function.

Conclusion

Side-to-side neurorrhaphy appears to be promising as a feasible method for repair of high-level peripheral nerve injuries.

Reverse end-to-side nerve transfer: from animal model to clinical use

PURPOSE

Functional recovery after peripheral nerve injury is predominantly influenced by time to reinnervation and number of regenerated motor axons. For nerve injuries in which incomplete regeneration is anticipated, a reverse end-to-side (RETS) nerve transfer might be useful to augment the regenerating nerve with additional axons and to more quickly reinnervate target muscle. This study evaluates the ability of peripheral nerve axons to regenerate across an RETS nerve transfer. We present a case report demonstrating its potential clinical applicability.

METHODS

Thirty-six Lewis rats were randomized into 3 groups. In group 1 (negative control), the tibial nerve was transected and prevented from regenerating. In group 2 (positive control), the tibial and peroneal nerves were transected, and an end-to-end (ETE) nerve transfer was performed. In group 3 (experimental model), the tibial nerve and peroneal nerves were transected, and an RETS nerve transfer was performed between the proximal end of the peroneal nerve and the side of the denervated distal tibial stump. Nerve histomorphometry and perfused muscle mass were evaluated. Six Thy1-GFP transgenic Sprague Dawley rats, expressing green fluorescent protein in their neural tissues, also had the RETS procedure for evaluation with confocal microscopy.

RESULTS

Nerve histomorphometry showed little to no regeneration in chronic denervation animals but statistically similar regeneration in ETE and RETS animals at 5 and 10 weeks. Muscle mass preservation was similar between ETE and RETS groups by 10 weeks and significantly better than negative controls at both time points. Nerve regeneration was robust across the RETS coaptation of Thy1-GFP rats by 5 weeks.

CONCLUSIONS

Axonal regeneration occurs across an RETS coaptation. An RETS nerve transfer might augment motor recovery when less-than-optimal recovery is otherwise anticipated.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic I.

Adult peripheral nerve disorders: nerve entrapment, repair, transfer, and brachial plexus disorders

LEARNING OBJECTIVES

After reading this article, the participant should be able to: 1. Describe the pathophysiologic bases for nerve injury and how they apply to patient evaluation and management. 2. Recognize the wide variety of injury patterns and associated patient complaints and physical findings associated with peripheral nerve pathology. 3. Evaluate and recommend further tests to aid in defining the diagnosis. 4. Specify treatment options and potential risks and benefits.

SUMMARY

Peripheral nerve disorders comprise a gamut of problems, ranging from entrapment neuropathy to direct open traumatic injury and closed brachial plexus injury. The pathophysiology of injury defines the patient's symptoms, examination findings, and treatment options and is critical to accurate diagnosis and treatment. The goals of treatment include management of the often associated pain and improvement of sensory and motor function. Understanding peripheral nerve anatomy is critical to adopting novel nerve transfer procedures, which may provide superior options for a variety of injury patterns.

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

These case reports review the clinical outcomes of 4 patients who underwent nerve transfer to a triceps motor branch of the radial nerve. Mean follow-up was 26 ± 15 months. Two patients had a transfer using an ulnar nerve fascicle to the flexor carpi ulnaris muscle, yielding a motor recovery of grade M5 elbow extension strength in one case and M4+ in the other. In 1 patient, a thoracodorsal nerve branch was used as the donor; this patient recovered M4 strength. One patient had a transfer using a radial nerve fascicle to the extensor carpi radialis longus muscle and recovered M5 strength. These outcomes indicate that expendable fascicles of the ulnar, thoracodorsal, and radial nerves are viable donors in the surgical reconstruction of elbow extension.