End-to-side nerve grafting of the tibial nerve to bridge a neuroma-in-continuity

End-to-Side vs. Free Graft Nerve Reconstruction-Experimental Study on Rats

The long history of regeneration nerve research indicates many clinical problems with surgical reconstruction to be resolved. One of the promising surgical techniques in specific clinical conditions is end-to-side neurorrhaphy (ETS), described and then repeated with different efficiency in the 1990s of the twentieth century. There are no reliable data on the quality of recipient nerve regeneration, possible donor nerve damage, and epineural window technique necessary to be performed. This research attempts to evaluate the possible regeneration after end-to-side neurorrhaphy, its quality, potential donor nerve damage, and the influence of epineural windows on regeneration efficiency. Forty-five female Wistar rats were divided into three equal groups, and various surgical technics were applied: A-ETS without epineural window, B-ETS with epineural window, and C-free graft reconstruction. The right peroneal nerve was operated on, and the tibial nerve was selected as a donor. After 24 weeks, the regeneration was evaluated by (1) footprint analysis every two weeks with PFI (peroneal nerve function index), TFI (tibial nerve function index), and SFI (sciatic nerve function index) calculations; (2) the amplitude and latency measurements of motor evoked potentials parameters recorded on both sides of the peroneal and tibial nerves when electroneurography with direct sciatic nerve electrical stimulation and indirect magnetic stimulation were applied; (3) histomorphometry with digital conversion of a transverse semithin nerve section, with axon count, fibers diameter, and calculation of axon area with a semiautomated method were performed. There was no statistically significant difference between the groups investigated in all the parameters. The functional indexes stabilized after eight weeks (PFI) and six weeks (TFI and SFI) and were positively time related. The lower amplitude of tibial nerve potential in groups A and B was proven compared to the non-operated side. Neurophysiological parameters of the peroneal nerve did not differ significantly. Histomorphometry revealed significantly lower diameter and area of axons in operated peroneal nerves compared to non-operated nerves. The axon count was at a normal level in every group. Tibial nerve parameters did not differ from non-operated values. Regeneration of the peroneal nerve after ETS was ascertained to be at the same level as in the case of free graft reconstruction. Peroneal nerves after ETS and free graft reconstruction were ascertained to have a lower diameter and area than non-operated ones. The technique of an epineural window does not influence the regeneration result of the peroneal nerve. The tibial nerve motor evoked potentials were characterized by lower amplitudes in ETS groups, which could indicate axonal impairment.

Traumatic neuromas of peripheral nerves: Diagnosis, management and future perspectives

Traumatic neuromas are infrequent in clinical settings but are prevalent following trauma or surgery. A traumatic neuroma is not a true malignancy, rather, it is a hyperplastic, reparative nerve reaction after injury and typically manifests as a nodular mass. The most common clinical manifestations include painful hypersensitivity and the presence of a trigger point that causes neuralgic pain, which could seriously decrease the living standards of patients. While various studies are conducted aiming to improve current diagnosis and management strategies via the induction of emerging imaging tools and surgical or conservative treatment. However, researchers and clinicians have yet to reach a consensus regarding traumatic neuromas. In this review, we aim to start with the possible underlying mechanisms of traumatic neuromas, elaborate on the diagnosis, treatment, and prevention schemes, and discuss the current experiment models and advances in research for the future management of traumatic neuromas.

Better nerve regeneration with distally based fascicular turnover flap than with conventional autologous nerve graft in a rat sciatic nerve defect model

The authors hypothesize that a fascicular turnover flap will achieve better nerve regeneration in nerve gap repair than a conventional nerve graft in a rat sciatic nerve defect model. Seven-millimeter-long sciatic nerve defects were repaired with an autologous nerve graft, a proximal fascicular turnover flap, or a distal fascicular turnover flap. Following walking footprint analysis 8 weeks after the surgery, the gastrocnemius-soleus muscles of the hind limbs, nerve graft, and flaps were harvested for wet muscle weight assessment, immunohistochemistry, and transmission electron microscopy. The distal fascicular turnover flap exhibited improvement in the sciatic function index similar as that observed for the autologous nerve graft. Histologically, cross sections showed a higher staining intensity for S-100 in the distal fascicular turnover flap group than for S-100 in the nerve graft group (p = 0.01). In the longitudinal sections, the staining intensity for NF-200 was higher in the distal fascicular turnover flap group than in the nerve graft (p = 0.009) and proximal fascicular turnover flap (p = 0.004) groups. More mature capillaries were observed in the proximal (p < 0.001) and distal (p = 0.029) fascicular turnover flap groups than in the nerve graft group. Transmission electron microscopy results showed a compact, regular myelin sheath around the myelinated nerve fibers in the distal fascicular turnover flap group, unlike observations in the nerve graft and proximal fascicular turnover flap groups. This study demonstrates better nerve regeneration in nerve gap repair with the distal fascicular turnover flap than with the conventional nerve graft.

Outcomes of the surgical treatment of peripheral neuromas of the hand and forearm: a 25-year comparative outcome study

PURPOSE

Peripheral neuromas within the upper extremity result in significant disability. Treatment options vary, and established protocols have yet to be determined. We performed a long-term outcome comparison examining different treatment options for peripheral upper extremity neuromas to determine which method provided superior results using a validated upper extremity outcome measurement system.

METHODS

A retrospective chart review was performed for all patients undergoing surgical intervention from 1980 to 2005 for a symptomatic neuroma of the hand or forearm. Patients' charts were reviewed for medical history, etiology of neuroma, and treatment outcomes. Patients were surveyed using the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire and pain evaluation questionnaires.

RESULTS

We identified 127 eligible patients who had their index procedure performed at our institution. Fifty-six patients completed the questionnaires. In all cases, verification of a neuroma was made on pathologic and surgical examination. Follow-up averaged 240 months from the time of surgery. Mean age at the time of surgery was 40 years (range, 19-72 years). Of all the patients, 11 were treated with muscle or bone transposition, 17 with simple excision, and 28 with nerve repair and neurolysis. Mean DASH score at the final follow-up was 19.75 (range, 0-78.3). Patients who underwent neuroma excision with nerve repair had significantly lower postoperative DASH scores, averaging 11.42, compared with either muscle or bone transposition or simple excision (mean DASH score, 22.4 and 32.0, respectively, P = 0.01). The number of neuroma procedures (P = 0.04), preoperative pain severity (P = 0.03), and postoperative pain severity (P = 0.04) all affected the final DASH score. Fifteen patients (27%) required more than 1 surgery. Simple neuroma excision resulting in the highest incidence of reoperations (47%).

CONCLUSIONS

Treatment of upper extremity neuromas remains a complicated problem. Within this study, nerve repair yielded improved DASH scores compared with nerve transposition or the use of simple resection. Resection alone was associated with an unacceptable recurrence rate and should be discouraged as treatment for upper extremity neuromas. Prior surgical procedures, neuroma size, and the severity of preoperative pain may all adversely impact the success of surgical intervention.

Traumatic neuroma in continuity injury model in rodents

Traumatic neuroma in continuity (NIC) results in profound neurological deficits, and its management poses the most challenging problem to peripheral nerve surgeons today. The absence of a clinically relevant experimental model continues to handicap our ability to investigate ways of better diagnosis and treatment for these disabling injuries. Various injury techniques were tested on Lewis rat sciatic nerves. Optimal experimental injuries that consistently resulted in NIC combined both intense focal compression and traction forces. Nerves were harvested at 0, 5, 13, 21, and 65 days for histological examination. Skilled locomotion and ground reaction force (GRF) analysis were performed up to 9 weeks on the experimental (n=6) and crush-control injuries (n=5). Focal widening, disruption of endoneurium and perineurium with aberrant intra- and extrafascicular axonal regeneration and progressive fibrosis was consistently demonstrated in 14 of 14 nerves with refined experimental injuries. At 8 weeks, experimental animals displayed a significantly greater slip ratio in both skilled locomotor assessments, compared to nerve crush animals (p<0.01). GRFs of the crush- injured animals showed earlier improvement compared to the experimental animals, whose overall GRF patterns failed to recover as well as the crush group. We have demonstrated histological features and poor functional recovery consistent with NIC formation in a rat model. The injury mechanism employed combines traction and compression forces akin to the physical forces at play in clinical nerve injuries. This model may serve as a tool to help diagnose this injury earlier and to develop intervention strategies to improve patient outcomes.

Effect of end-to-side repair of proximal nerve stumps of transected peripheral nerves on the development of neuroma (experimental study)

OBJECTIVE

Neuroma is a psychologically and physically disabling problematic condition without any current standard therapy. For that reason, we investigated whether end-to-side anastomosis of the proximal end of the transected nerve into the adjacent nerve will prevent the development of neuroma in different types of nerve injuries.

STUDY DESIGN

In this study, hind legs of 18 Sprague-Dawley female rats were used. Six groups were formed. In group I, peroneal nerves were transected and its proximal end was attached end-to-side through the epineural window to the adjacent tibial nerve. In group II, contrary to group I, an epineural window was created in the tibial nerve and the same number of sutures were employed. In group III, tibial nerve was transected proximal to the end-to-side repair site, whereas in group IV, distal segment of the nerve was cut, and an end-to-end repair procedure was repeated. In group V, unlike group I, an approximately 1-cm segment was resected and removed distal (from tibial nerve) to the end-to-side repair site. In group VI, an epineural window was created in the tibial nerve and the same number of sutures were used, and also a 1-cm distal nerve segment was resected. The rats were followed for 2 months, and then all of the groups were evaluated histopathologically, and weights of the posterior muscle groups of hind legs were evaluated.

FINDINGS AND CONCLUSIONS

No neuroma formation was observed in the proximal stumps of peroneal nerve segments in end-to-side repair sites in groups I, III, IV, and V, and proximal stumps of the tibial nerve in group V. In group VI, neuroma formation was observed in the proximal end of the tibial nerve. When weights of the posterior muscle groups of hind legs in groups I and II were comparatively assessed, statistically significant difference was not detected. In conclusion, based on histological data obtained for proximal nerve ends and segments distal to the end-to-side repair sites, we think that end to side neurorrhaphy of the proximal end of the damaged nerve to adjacent nerve will prevent the development of neuroma without injuring the intact nerve segment.

Augmentation of partially regenerated nerves by end-to-side side-to-side grafting neurotization: experience based on eight late obstetric brachial plexus cases

OBJECTIVE

The effect of end-to-side neurotization of partially regenerated recipient nerves on improving motor power in late obstetric brachial plexus lesions, so-called nerve augmentation, was investigated.

METHODS

Eight cases aged 3-7 years were operated upon and followed up for 4 years (C5,6 rupture C7,8 T1 avulsion: 5; C5,6,7,8 rupture T1 avulsion: 1; C5,6,8 T1 rupture C7 avulsion: 1; C5,6,7 rupture C8 T1 compression: one 3 year presentation after former neurotization at 3 months). Grade 1-3 muscles were neurotized. Grade 0 muscles were neurotized, if the electromyogram showed scattered motor unit action potentials on voluntary contraction without interference pattern. Donor nerves included: the phrenic, accessory, descending and ascending loops of the ansa cervicalis, 3rd and 4th intercostals and contralateral C7.

RESULTS

Superior proximal to distal regeneration was observed firstly. Differential regeneration of muscles supplied by the same nerve was observed secondly (superior supraspinatus to infraspinatus regeneration). Differential regeneration of antagonistic muscles was observed thirdly (superior biceps to triceps and pronator teres to supinator recovery). Differential regeneration of fibres within the same muscle was observed fourthly (superior anterior and middle to posterior deltoid regeneration). Differential regeneration of muscles having different preoperative motor powers was noted fifthly; improvement to Grade 3 or more occurred more in Grade 2 than in Grade 0 or Grade 1 muscles. Improvements of cocontractions and of shoulder, forearm and wrist deformities were noted sixthly. The shoulder, elbow and hand scores improved in 4 cases.

LIMITATIONS

The sample size is small. Controls are necessary to rule out any natural improvement of the lesion. There is intra- and interobserver variability in testing muscle power and cocontractions.

CONCLUSION

Nerve augmentation improves cocontractions and muscle power in the biceps, pectoral muscles, supraspinatus, anterior and lateral deltoids, triceps and in Grade 2 or more forearm muscles. As it is less expected to improve infraspinatus power, it should be associated with a humeral derotation osteotomy and tendon transfer. Function to non improving Grade 0 or 1 forearm muscles should be restored by muscle transplantation.

LEVEL OF EVIDENCE

Level IV, prospective case series.

Neuroma-in-Continuity Model in Rabbits

The present study presents a model for creation of neuroma-in-continuity in the rabbit, confirmed by histologic study, electrophysiology, and examination of molecular markers. Twelve New Zealand rabbits were used. The lateral fascicule of the peroneal nerve with 15-mm in length was resected. In the intervals from 4 to 6 weeks postoperatively, the histology showed the typical pathologic changes of neuroma by hematoxylin-eosin (HE), Luxol fast blue, and Van-Gieson staining. As compared with the healthy nerve, the motor nerve conduction velocity (MCV) and compound motor action potential (CMAP) were found significantly slowed and reduced. The expression of ciliary neurotrophic factor (CNTF) in nerve and calcitonin gene-related peptide (CGRP) mRNA in L7, S1 dorsal root ganglia were downgraded and upgraded, respectively, with formation of neuroma-in-continuity. These electrophysiologic and molecular markers' expression data can be used as reliable parameters for evaluation of management of the neuroma-in-continuity.

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.