Clinical Experience with End-to-Side Nerve Transfer

Reverse End-to-Side Nerve Transfer for Severe Ulnar Nerve Injury: A Western Canadian Multicentre Prospective Nonrandomized Cohort Study

BACKGROUND

Reverse end-to-side (RETS) nerve transfer has become increasingly popular in patients with severe high ulnar nerve injury, but the reported outcomes have been inconsistent.

OBJECTIVE

To evaluate the "babysitting effect," we compared outcomes after anterior interosseous nerve RETS transfer with nerve decompression alone. To evaluate the source of regenerating axons, a group with end-to-end (ETE) transfer was used for comparisons.

METHODS

Electrophysiology measures were used to quantify the regeneration of anterior interosseous nerve (AIN) and ulnar nerve fibers while functional recovery was evaluated using key pinch and Semmes-Weinstein monofilaments. The subjects were followed postsurgically for 3 years.

RESULTS

Sixty-two subjects (RETS = 25, ETE = 16, and decompression = 21) from 4 centers in Western Canada were enrolled. All subjects with severe ulnar nerve injury had nerve compression at the elbow except 10 in the ETE group had nerve laceration or traction injury. Postsurgically, no reinnervation from the AIN to the abductor digiti minimi muscles was seen in any of the RETS subjects. Although there was no significant improvement in compound muscle action potentials amplitudes and pressure detection thresholds in the decompression and RETS group, key pinch strength significantly improved in the RETS group ( P < .05).

CONCLUSION

The results from published clinical trials are conflicting in part because crossover regeneration from the donor nerve has never been measured. Unlike those with ETE nerve transfers, we found that there was no crossover regeneration in the RETS group. The extent of reinnervation was also no different from decompression surgery alone. Based on these findings, the justifications for this surgical technique need to be carefully re-evaluated.

Sensorimotor Outcomes of Upper Extremity End-to-Side Nerve Transfers: A Meta-analysis

BACKGROUND

End-to-side nerve transfer (ETSNT) for treatment of peripheral nerve injuries is controversial given the myriad anatomic locations, injury types, and indications. Efficacy of ETSNT remains debated. We hypothesized differences in age, sex, transfer location, and time to surgery influence outcomes.

METHODS

We performed a search of the PubMed database for ETSNT in the upper extremity from 1988 to 2018. Age, sex, transfer location, time to surgery, donor and recipient axons, and strength and sensation outcomes as measured by Medical Research Council scale were extracted from articles. Meaningful recovery was classified as Medical Research Council Grade 3 or greater. Association between meaningful recovery and younger (<25) and older (≥25) patients, injury mechanism, sex, transfer location, donor axons, and recipient axons were calculated using a χ 2 or Fisher exact test. A logistic mixed effect model was used with time to surgery, age (categorical), transfer location, and injury type as a fixed effect, and a random paper effect was included to account for correlation among patients from the same paper.

RESULTS

One hundred fifteen patients from 11 studies were included. Neither age (continuous variable, P = 0.68) nor time to surgery ( P = 0.28) affected meaningful recovery. Injury mechanism, sex, and younger age (<25 vs ≥25 years) were not associated with meaningful recovery. Within the brachial plexus ETSNT demonstrated median M4 ± 1 postoperative strength, with trunks/cords as the primary axon donor ( P = 0.03). The musculocutaneous nerve demonstrated promising but variable results in 31 patients with median strength M3 ± 4. Digital nerves consistently demonstrated meaningful sensory recovery as both donor and recipient axons (15 of 15, 100%). Logistic regression analysis demonstrated that odds of meaningful recovery after ETSNT are significantly greater for transfers within the brachial plexus compared with the distal arm (odds ratio, 41.9; 95% CI, 1.1-1586.7, P = 0.04), but location does not significantly affect meaningful recovery ( P = 0.22).

CONCLUSIONS

Patients undergoing ETSNT for digital nerve injury demonstrated meaningful recovery. End-to-side nerve transfer seems to be more efficacious when performed within the brachial plexus. This study did not find sex, injury mechanism, or time to surgery to significantly affect meaningful recovery. Additional study is needed to better evaluate the effectiveness of ETSNT in the upper extremity.

Teaching Hand Surgery in the Developing World: Utilizing Educational Resources in Global Health

The development of surgical capacity in the developing world is essential to address the global burden of surgical disease. Training local surgeons in low-income and middle-income countries is critical in this endeavor. The challenges to teaching hand surgery in the developing world include a shortage of local faculty, absence of a defined curriculum, no competency-based evaluation systems, few subspecialty training opportunities, and lack of financial support. To teach hand surgery in the developing world effectively, the authors suggest principles and components of a global training curriculum.

Clinical applications of end-to-side neurorrhaphy: an update

End-to-side neurorrhaphy constitutes an interesting option to regain nerve function after damage in selected cases, in which conventional techniques are not feasible. In the last twenty years, many experimental and clinical studies have been conducted in order to understand the biological mechanisms and to test the effectiveness of this technique, with contrasting results. In this updated review, we consider the state of the art about end-to-side coaptation, focusing on all the current clinical applications, such as sensory and mixed nerve repair, treatment of facial palsy, and brachial plexus injuries and painful neuromas management.

Influence of breaching the connective sheaths of the donor nerve on its myelinated sensory axons and on their sprouting into the end-to-side coapted nerve in the rat

The influence of breaching the connective sheaths of the donor sural nerve on axonal sprouting into the end-to-side coapted peroneal nerve was examined in the rat. In parallel, the effect of these procedures on the donor nerve was assessed. The sheaths of the donor nerve at the coaptation site were either left completely intact (group A) or they were breached by epineurial sutures (group B), an epineurial window (group C), or a perineurial window (group D). In group A, the compound action potential (CAP) of sensory axons was detected in ~10% and 40% of the recipient nerves at 4 and 8 weeks, respectively, which was significantly less frequently than in group D at both recovery periods. In addition, the number of myelinated axons in the recipient nerve was significantly larger in group D than in other groups at 4 weeks. At 8 weeks, the number of axons in group A was only ~15% of the axon numbers in other groups (p<0.05). Focal subepineurial degenerative changes in the donor nerves were only seen after 4 weeks, but not later. The average CAP area and the total number of myelinated axons in the donor nerves were not different among the experimental groups. In conclusion, myelinated sensory axons are able to penetrate the epiperineurium of donor nerves after end-to-side nerve coaption; however, their ingrowth into recipient nerves is significantly enhanced by breaching the epiperineurial sheets at the coaptation site. Breaching does not cause permanent injury to the donor nerve.

Outcome following nerve repair of high isolated clean sharp injuries of the ulnar nerve

OBJECTIVE

The detailed outcome of surgical repair of high isolated clean sharp (HICS) ulnar nerve lesions has become relevant in view of the recent development of distal nerve transfer. Our goal was to determine the outcome of HICS ulnar nerve repair in order to create a basis for the optimal management of these lesions.

METHODS

High ulnar nerve lesions are defined as localized in the area ranging from the proximal forearm to the axilla just distal to the branching of the medial cord of the brachial plexus. A meta-analysis of the literature concerning high ulnar nerve injuries was performed. Additionally, a retrospective study of the outcome of nerve repair of HICS ulnar nerve injuries at our institution was performed. The Rotterdam Intrinsic Hand Myometer and the Rosén-Lundborg protocol were used.

RESULTS

The literature review identified 46 papers. Many articles presented outcomes of mixed lesion groups consisting of combined ulnar and median nerves, or the outcome of high and low level injuries was pooled. In addition, outcome was expressed using different scoring systems. 40 patients with HICS ulnar nerve lesions were found with sufficient data for further analysis. In our institution, 15 patients had nerve repair with a median interval between trauma and reconstruction of 17 days (range 0-516). The mean score of the motor and sensory domain of the Rosen's Scale instrument was 58% and 38% of the unaffected arm, respectively. Two-point discrimination never reached less then 12 mm.

CONCLUSION

From the literature, it was not possible to draw a definitive conclusion on outcome of surgical repair of HICS ulnar nerve lesions. Detailed neurological function assessment of our own patients showed that some ulnar nerve function returned. Intrinsic muscle strength recovery was generally poor. Based on this study, one might cautiously argue that repair strategies of HICS ulnar nerve lesions need to be improved.

Distal anterior interosseous nerve transfer to the deep ulnar nerve and end-to-side suture of the superficial ulnar nerve to the third common palmar digital nerve for treatment of high ulnar nerve injuries: experience in five cases

OBJECTIVE: To demonstrate the results of a double nerve transfer at the level of the hand for recovery of the motor and sensory function of the hand in cases of high ulnar nerve injuries. METHOD: Five patients underwent a transfer of the distal branch of the anterior interosseous nerve to the deep ulnar nerve, and an end-to-side suture of the superficial ulnar nerve to the third common palmar digital nerve. RESULTS: Two patients recovered strength M3 and three cases were graded as M4; recovery of protective sensation (S3+ in three patients and S4 in two) was observed in the fourth and fifth fingers, and at the hypothenar region. The monofilament test showed values of 3.61 or less in all cases and the two-point discrimination test demonstrated values of 7 mm in three cases and 5 mm in two. CONCLUSION: This technique of double nerve transfer is effective for motor and sensory recovery of the distal ulnar-innervated side of the hand.

Experimental and clinical employment of end-to-side coaptation: our experience

The last 15 years have seen a growing interest regarding a technique for nerve repair named end-to-side coaptation. Since 2000, we have carried out experimental studies on end-to-side nerve repair as well as employed this technique to a series of selected clinical cases. Here we report on the results of this experience.For experimental studies, we have used the model represented by median nerve repair by end-to-side coaptation either on the ulnar (agonistic) or the radial (antagonistic) nerve. For time course assessment of median nerve functional recovery we used the grasping test, a test which permits to assess voluntary control of muscle function. Repaired nerves were processed for resin embedding to allow nerve fibre stereology and electron microscopy. Results showed that, in either experimental group, end-to-side-repaired median nerves were repopulated by axons regenerating from ulnar and radial donor nerves, respectively. Moreover, contrary to previously published data, our results showed that voluntary motor control of the muscles innervated by the median nerve was progressively recovered also when the antagonistic radial nerve was the donor nerve.As regards our clinical experience, results were not so positive. We have treated by end-to-side coaptation patients with both sensory (n = 7, collateral digital nerves) and mixed (n = 8, plexus level) nerve lesions. Results were good, as in other series, in sensory nerves whilst they were very difficult to investigate in mixed nerves at the plexus level.Take together, these results suggest that clinical employment of end-to-side coaptation should still be considered at the moment as the ultima ratio in cases in which no other repair technique can be attempted. Yet, it is clear that more basic research is needed to explain the reasons for the different results between laboratory animal and humans and, especially, to find out how to ameliorate the outcome of end-to-side nerve repair by adequate treatment and rehabilitation.

Avaliação histológica da neurorrafia término-lateral: estudo experimental em ratos

OBJETIVO: Realizar estudo histológico comparando o crescimento axonal após neurorrafia término-lateral com e sem epineurectomia. MÉTODOS: foram utilizados vinte ratos Wistar, machos, divididos em dois grupos de 10 ratos cada. Um segmento de 1,0cm do nervo tibial e, foi transposto para o lado contralateral, sendo suturado no nervo ciático D. No grupo I, a sutura foi realizada diretamente no epineuro, enquanto que no grupo II foi realizado epineurectomia. Após 4 semanas foi realizado avaliação histológica do segmento transposto e no nervo ciático D, no sitio distal à lesão. RESULTADOS: demonstrou-se baixa quantidade de fibras remielinizadas, variando de 7 a 51 fibras no Grupo I e de 10 a 91 fibras no Grupo II. Utilizou-se o teste U de Mann-Whitney, com p=0,31, demonstrando que não há diferença estatisticamente significante entre os dois grupos. Não há relação positiva entre o número de fibras remielinizadas no enxerto e no sitio distal à lesão do ciático. CONCLUSÃO: A neurorrafia término-lateral, com e sem janela epineural, não promove remielinização eficiente. Nivel de evidência: Nível II: Estudo prospectivo comparativo

Termino-lateral nerve suture in lesions of the digital nerves: clinical experience and literature review

Documented experience of treatment of digital nerve lesions with the termino-lateral (end-to-side) nerve suture is limited. Our clinical experience of this technique is detailed here alongside a systematic review of the previous literature. We performed, from 2002 to 2008, seven termino-lateral sutures with epineural window opening for digital nerve lesions. Functional outcome was analysed using the two-point discrimination test and the Semmes-Weinstein monofilament test. The results showed a sensory recovery of S3+ in six cases and S3 in one case. The mean distance found in the two-point discrimination test was 12.7 mm (range 8-18 mm). After a review of the literature, we were able to obtain homogeneous data from 17 additional patients operated by termino-lateral coaptation. The overall number of cases included in our review was 24. A sensory recovery was observed in 23 out of 24 patients. The functional results were S0 in one case, S3 in one case, S3+ in twenty cases and S4 in two cases. Excluding the one unfavourable case, the mean distance in the two-point discrimination test was 9.7 mm (range 3-18 mm). It can thus be concluded that the treatment of digital nerve lesions with termino-lateral suture showed encouraging results. Based on the results obtained in this current study we believe that in case of loss of substance, end-to-side nerve coaptation may be an alternative to biological and synthetic tubulisation when a digital nerve reconstruction by means of nerve autograft is declined by the patient.

End-to-side nerve suture in traumatic injuries of brachial plexus: review of the literature and personal case series

We used end-to-side nerve coaptation combined with standard end-to-end neurotisations to treat 11 patients who presented with complete (six cases) or incomplete (five cases) traumatic brachial plexus injuries. All patients were available for functional evaluation at a minimum of 2 years postoperatively. In three patients with shoulder abduction recovery, electromyographical studies (EMG) showed a contribution from the end-to-side neurotisation. In the remaining cases end-to-side neurotisations were unsuccessful. Our study did not demonstrate a reliable role for end-to-side nerve suture in brachial plexus surgery. We believe that at present end-to-side suture must not be a substitute for standard reconstructive techniques in brachial plexus surgery. Occasionally termino-lateral nerve sutures may represent a support to standard reconstructive procedures especially in case of severe injuries when few undamaged donor nerves are available.

End-to-side neurorrhaphy for median nerve repair after elbow tumor resection: case report

We report a case of a median to ulnar end-to-side neurorrhaphy with epineurectomy but without fascicular donor nerve section. Surgery was performed for the curative treatment of an elbow synovial sarcoma at the level of the elbow that necessitated resection of 10 cm of the median nerve. The patient was followed up for 24 months. After 4 months, a recovery of protective sensation in the territory of the median nerve was noticed and had stabilized by 1 year.

Nerve transfers in the forearm and hand

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

Sex-related differences in recovery of cutaneous nociception after end-to-side nerve repair in the rat

Sex-related differences in the recovery of cutaneous nociception after end-to-side nerve repair were examined in rats. Recovery of nociception in the dorsal foot was determined by skin pinch test 19 weeks after the proximal end of the distal stump of the transected peroneal nerve was sutured to the side of the adjacent intact sural nerve (end-to-side nerve coaptation). Axon sprouts in the recipient peroneal nerve were counted by light and electron microscopy. Recovery of nociception due to axon sprouting through the end-to-side coaptation was found in 87% of females and in 60% of males. The area of nociception was not significantly different (P=0.59) between females and males (13+/-8% and 11+/-9%, respectively). The number of myelinated axons in the recipient peroneal nerve (but not of unmyelinated axons) was significantly larger (P=0.028) in females (median=512, 25th and 75th percentiles: 467 and 594) than in males (median=322, 25th and 75th percentiles: 239 and 468). The majority of these axons in females and males were thin fibres, and recipient nerves in both groups were responsive to nerve pinch test. In conclusion, collateral sprouting of thin myelinated nociceptive axons into the end-to-side coapted nerve is more abundant in female than in male rats. However, recovery of cutaneous mechano-nociception due to sprouting of these axons was not different between the two sexes. Possible reasons are discussed.

RESULTS OF END-TO-SIDE NERVE COAPTATION IN SEVERE OBSTETRIC BRACHIAL PLEXUS LESIONS

OBJECTIVE

Options for nerve repair are limited in brachial plexus lesions with multiple root avulsions because an insufficient number of proximal nerve stumps are available to serve as lead-out for nerve grafts. End-to-side nerve repair might be an alternative surgical technique for repair of such severe lesions. In this technique, an epineurial window is created in a healthy nerve, and the distal stump of the injured nerve is coapted to this site. Inconsistent results of end-to-side nerve repairs in traumatic nerve lesions in adults have been reported in small series. This article evaluates the results of end-to-side nerve repair in obstetric brachial plexus lesions and reviews the literature.

METHODS

A retrospective analysis was performed of 20 end-to-side repairs in 12 infants. Evaluation of functional recovery of the target muscle was performed after at least 2 years of follow up (mean, 33 mo).

RESULTS

Five repairs failed (25%). Seven times (35%) good function (Medical Research Council at least 3) of the target muscle occurred in addition to eight partial recoveries (40%). In the majority of patients, however, the observed recovery cannot be exclusively attributed to the end-to-side repair. The reinnervation may be based on axonal outgrowth through grafted or neurolyzed adjacent nerves. It seems likely that recovery was solely based on the end-to-side repair in only two patients. No deficits occurred in donor nerve function.

CONCLUSION

This study does not convincingly show that the end-to-side nerve repair in infants with an obstetric brachial plexus lesion is effective. Its use cannot be recommended as standard therapy.

Simultaneous end-to-side coaptations of two severed nerves to a single healthy nerve in rats

Object

This experimental study was designed to evaluate functional and sensory outcomes and morphological features observed after simultaneous end-to-side coaptations of distal stumps of two nerves to a single neighboring nerve. Studies were performed using both parallel and end-to-side coaptation (PEC) and serial end-to-side coaptation (SEC) methods in a rat model.

Methods

In the PEC group, distal stumps of the sural and common fibular nerves were coapted to the intact tibial nerve 1 cm apart from each other in an end-to-side fashion. In the SEC group, identical surgical procedures apart from the coaptation method were conducted. For the coaptation method in this group, the distal stump of the common fibular nerve was first coapted to the side of the intact tibial nerve, and then the distal stump of the sural nerve was coapted to the side of the common fibular nerve 1 cm apart from the first coaptation site.

Nonoperated contralateral sides were used as controls. Nerve regeneration in both groups was evaluated functionally, electrophysiologically, and histomorphometrically.

Conclusions

When there is a need for two end-to-side coaptations of two severed nerves, PEC is the recommended method of choice to obtain better axonal regeneration into both nerves.

A unique case of total foot-to-hand transfer in an infant with monodactyly

A unique case of total foot-to-hand transfer, including the calcaneus, in an 8 month-old infant with monodactyly is described. Several technical and psychological aspects of the case are also discussed.