Conditioning Electrical Stimulation Accelerates Regeneration in Nerve Transfers.

OBJECTIVE: Compared to the upper limb, lower limb distal nerve transfer (DNT) outcomes are poor, likely due to the longer length of regeneration required. DNT surgery to treat foot drop entails rerouting a tibial nerve branch to the denervated common fibular nerve stump to reinnervate the tibialis anterior muscle for ankle dorsiflexion. Conditioning electrical stimulation (CES) prior to nerve repair surgery accelerates nerve regeneration and promotes sensorimotor recovery. We hypothesize that CES prior to DNT will promote nerve regeneration to restore ankle dorsiflexion. METHODS: One week following common fibular nerve crush, CES was delivered to the tibial nerve in half the animals, and at 2 weeks, all animals received a DNT. To investigate the effects of CES on nerve regeneration, a series of kinetic, kinematic, skilled locomotion, electrophysiologic, and immunohistochemical outcomes were assessed. The effects of CES on the nerve were investigated. RESULTS: CES-treated animals had significantly accelerated nerve regeneration (p < 0.001), increased walking speed, and improved skilled locomotion. The injured limb had greater vertical peak forces, with improved duty factor, near-complete recovery of braking, propulsive forces, and dorsiflexion (p < 0.01). Reinnervation of the tibialis anterior muscle was confirmed with nerve conduction studies and immunohistochemical analysis of the neuromuscular junction. Immunohistochemistry demonstrated that CES does not induce Wallerian degeneration, nor does it cause macrophage infiltration of the distal tibial nerve. INTERPRETATION: Tibial nerve CES prior to DNT significantly improved functional recovery of the common fibular nerve and its muscle targets without inducing injury to the donor nerve. ANN NEUROL 2020;88:363-374.

Conditioning Electrical Stimulation Is Superior to Postoperative Electrical Stimulation in Enhanced Regeneration and Functional Recovery Following Nerve Graft Repair.

Background. Autologous nerve graft is the most common clinical intervention for repairing a nerve gap. However, its regenerative capacity is decreased in part because, unlike a primary repair, the regenerating axons must traverse 2 repair sites. Means to promote nerve regeneration across a graft are needed. Postoperative electrical stimulation (PES) improves nerve growth by reducing staggered regeneration at the coaptation site whereas conditioning electrical stimulation (CES) accelerates axon extension. In this study, we directly compared these electrical stimulation paradigms in a model of nerve autograft repair. Methods. To lay the foundation for clinical translation, regeneration and reinnervation outcomes of CES and PES in a 5-mm nerve autograft model were compared. Sprague-Dawley rats were divided into: (a) CES, (b) PES, and (c) no stimulation cohorts. CES was delivered 1 week prior to nerve cut/coaptation, and PES was delivered immediately following coaptation. Length of nerve regeneration (n = 6/cohort), and behavioral testing (n = 16/cohort) were performed at 14 days and 6 to 14 weeks post-coaptation, respectively. Results. CES treated axons extended 5.9 ± 0.2 mm, significantly longer than PES (3.8 ± 0.2 mm), or no stimulation (2.5 ± 0.2 mm) (P < .01). Compared with PES animals, the CES animals had significantly improved sensory recovery (von Frey filament testing, intraepidermal nerve fiber reinnervation) (P < .001) and motor reinnervation (horizontal ladder, gait analysis, nerve conduction studies, neuromuscular junction analysis) (P < .01). Conclusion. CES resulted in faster regeneration through the nerve graft and improved sensorimotor recovery compared to all other cohorts. It is a promising treatment to improve outcomes in patients undergoing nerve autograft repair.

Side-to-side supercharging nerve allograft enhances neurotrophic potential.

INTRODUCTION: Critical limitations of processed acellular nerve allograft (PNA) are linked to Schwann cell function. Side-to-side bridge grafting may enhance PNA neurotrophic potential. METHODS: Sprague-Dawley rats underwent tibial nerve transection and immediate repair with 20-mm PNA (n = 33) or isograft (ISO; n = 9) or 40-mm PNA (n = 33) or ISO (n = 9). Processed acellular nerve allograft groups received zero, one, or three side-to-side bridge grafts between the peroneal nerve and graft. Muscle weight, force generation, and nerve histomorphology were tested 20 weeks after repair. Selected animals underwent neuron back labeling with fluorescent dyes. RESULTS: Inner axon diameters, g-ratios, and axon counts were smaller in the distal vs proximal aspect of each graft (P < .05). Schwann cell counts were greater, with a lower proportion of senescent cells for groups with bridges (P < .05). Retrograde labeling demonstrated that 6.6% to 17.7% of reinnervating neurons were from the peroneal pool. DISCUSSION: Bridge grafting positively influenced muscle recovery and Schwann cell counts and senescence after long PNA nerve reconstruction.

Donor nerve axotomy and axonal regeneration after end-to-side neurorrhaphy in a rodent model.

OBJECTIVE In this study, the authors used a surgical model of end-to-side neurorrhaphy between a nerve graft and a donor tibial nerve in adult rats to investigate the optimal conditions for axonal regeneration induced by the donor nerve. They also assessed the importance of a more favorable pathway using a predegenerated nerve graft to attract regenerating axons to regrow into the graft and then directing and improving their growth toward the target in comparison with results obtained with a fresh nerve graft. METHODS End-to-side neurorrhaphy was performed between a nerve graft and a donor tibial nerve. The nerve graft was obtained from the left tibial nerve, which was either freshly removed or predegenerated 1 week prior to neurorrhaphy. The donor right tibial nerve was injured by epineurium removal alone, injured by epineurium removal with cross section of 20% or 50% of the total axons at the coaptation site, or left intact. The animals were followed postoperatively for a 6-week period, and outcomes were evaluated by optical microscopy and retrograde labeling to detect the regenerated primary sensory neurons located in the lumbar dorsal root ganglia and spinal motor neurons located in the lumbar spinal ventral horn. RESULTS At the end of the follow-up period, no regenerating axons were observed in the nerve grafts when the donor nerve was left intact, and very few axons were detected when the donor nerve was injured by epineurium removal alone. However, numerous regenerating axons appeared in the grafts when the donor nerve was axotomized, and the greatest number was achieved with a 50% cross section axotomized nerve. In the rats with a 50% cross section of the donor nerve, better nerve-like morphology of the grafts was observed, without connective adhesions. When a predegenerated nerve graft was used, more regenerating axons were attracted and elongated with a more regular shape and improved myelination. CONCLUSIONS Axonal regrowth into a nerve graft depends on axotomy of the donor nerve after end-to-side neurorrhaphy. More efficient attraction and an improved structure of the regenerating axons were achieved when a predegenerated nerve graft was used. Furthermore, a nerve graft may require a certain number of regenerating axons to maintain a nerve-like morphology.

Dynamic Changes in Local Protein Synthetic Machinery in Regenerating Central Nervous System Axons after Spinal Cord Injury.

Intra-axonal localization of mRNAs and protein synthesis machinery (PSM) endows neurons with the capacity to generate proteins locally, allowing precise spatiotemporal regulation of the axonal response to extracellular stimuli. A number of studies suggest that this local translation is a promising target to enhance the regenerative capacity of damaged axons. Using a model of central nervous system (CNS) axons regenerating into intraspinal peripheral nerve grafts (PNGs) we established that adult regenerating CNS axons contain several different mRNAs and protein synthetic machinery (PSM) components in vivo. After lower thoracic level spinal cord transection, ascending sensory axons regenerate into intraspinal PNGs but axon growth is stalled when they reach the distal end of the PNG (3 versus 7 weeks after grafting, resp.). By immunofluorescence with optical sectioning of axons by confocal microscopy, the total and phosphorylated forms of PSMs are significantly lower in stalled compared with actively regenerating axons. Reinjury of these stalled axons increased axonal localization of the PSM proteins, indicative of possible priming for a subcellular response to axotomy. These results suggest that axons downregulate protein synthetic capacity as they cease growing, yet they retain the ability to upregulate PSM after a second injury.

Repairing peripheral nerve defects by vein grafts filled with adipose tissue derived stromal vascular fraction: an experimental study in rats.

BACKGROUND: There are many studies in the literature combining vein grafts with cell cultures, muscle, tendon, and nerve tissues, but none of them could replace isolated nerve grafts for nerve repair in clinical settings. There are studies in the literature indicating that adipose tissue derived stromal vascular fraction (SVF) enhances peripheral nerve healing. Considering these facts, an experimental study was performed in rats based on combining SVF with vein grafts for peripheral nerve defect repairs. METHODS: The study included 30 rats which were divided in three groups. In the first stage, an 8 mm nerve defect was created in tibial nerve of each rat. In Group 1, the defect was reconstructed with nerve graft, in Group 2, the defect was reconstructed with vein graft, and in Group 3, the defect was reconstructed with vein graft filled with SVF solution. After 3 months, the second surgical stage was performed and nerve biopsies were taken. Tissue samples were observed histopathologically. RESULTS: There were no statistically meaningful difference between nerve grafts, vein grafts and adipose tissue derived SVF- vein grafts combination groups considering myelin diameter and axonal diameter. Axon count was statistically superior in the nerve graft and study groups when compared to empty vein groups. CONCLUSION: In conclusion, our results support the usage of stromal vascular fraction-vein graft combination for peripheral nerve defect repairs.

Nerve Transfers for Persistent Traumatic Peroneal Nerve Palsy: The Inselspital Bern Experience.

BACKGROUND: Patients in whom conventional peroneal nerve repair surgery failed to reconstitute useful foot lift need to be evaluated for their suitability to undergo a concomitant tendon transfer procedure or nerve transfers. OBJECTIVE: To report our first clinical experience with nerve transfers for persistent traumatic peroneal nerve palsy. METHODS: Between 2007 and 2013, 8 patients were operated on for foot drop after unsuccessful nerve surgery. Six patients without fatty degeneration of the anterior tibial muscle and proximal lesion of the peroneal nerve were oriented for tibial to peroneal nerve transfer. In the other 2 cases where the anterior and lateral compartments were destructed, the anterior tibial muscle function was reconstructed with a neurotized lateral gastrocnemius transfer. For each patient, we graded postoperative results using the British Medical Research Council scheme and the Ninkovic assessment scale. RESULTS: Of the 6 patients who underwent nerve transfer of the anterior tibial muscle, 2 patients had excellent results, 1 patient had good results, 1 patient had fair results, and 2 patients had poor results. Of the 2 patients that underwent neurotized lateral gastrocnemius transfer, 1 patient achieved excellent results after tenolysis, whereas 1 patient achieved poor results. After the nerve transfer, 5 patients did not wear an ankle-foot orthosis. Four patients did not limp. Four patients were able to walk barefoot, navigate stairs, and participate in activities. CONCLUSION: Early clinical results after tibial to peroneal nerve transfer and neurotized lateral gastrocnemius transfer appear mixed. The results of nerve transfer seem, on the whole, less reliable than the literature reports on tendon transfer.

Medial plantar flap to repair defects of palm volar skin.

PURPOSE: The methods of repairing defects in fingers, volar skin of the palm and soft tissue were investigated. METHODS: From 2010 to the present, we examined 12 cases in which medial plantar skin flaps were used to repair defects in the fingers and palm. According to skin and soft tissue defects in the fingers and palm, a flap was designed using the medial plantar artery as the vessel pedicle. The flap was dissected and isolated between the abductor hallucis and flexor digitorum brevis, and transplanted to the hand. We then observed the skin colour, skin texture and tactile sensitivity of the hand, as well as the shape and function of the foot. RESULTS: Follow-up for 3-28 months showed that the flaps survived in all 12 cases, with soft skin, healthy appearance, colour consistent with the palm skin and no pigmentation. The two-point discrimination was 5-7 mm. The donor foot functioned well, and the scar at the donor site was slight and had an aesthetic appearance. CONCLUSION: The free medial plantar flap is an ideal flap for repairing soft tissue defects in the palm.

A gastrocnemius heterotopical transplant model with end-to-side neurorraphy.

PURPOSE: To present an animal model to assess the effects of end-to-side innervation in the heterotopically transplanted model with reduced chances of neural contamination. METHODS: The medial portion of the gastrocnemius muscle in wistar male rats was isolated and its pedicle dissected and performed a flap in the abdominal portion. To prevent neural contamination in the abdominal region, the muscle was wrapped with a Goretex(r) sheet. The specimens were divided into 2 groups (G). In G1 was performed an end-to-end suture between tibial nerve of the gastrocnemius and femoral motor nerve and between the saphenous sensory nerve and the motor nerve. In G2 was performed a end-to-side suture between the tibial nerve and the motor femoral and between the tibial nerve and saphenous motor nerve. The specimens were evaluated 60 days later to check the structure of the neurorraphy. Sections were obtained proximal and distal to the coaptation site. RESULTS: The medial gastrocnemius muscle had the advantage of maintaining visible mass after 60 days. No disruption of the coaptation site was found. No major injury to the donor nerve was seen in group 2. CONCLUSION: The proposed model is simple, reproduciple and prevent the neural contamination in the flap in end-to-side suture.

Effect of FK506 nanospheres on regeneration of allogeneic nerve after transplant.

OBJECTIVE: To discuss effect of FK506 nanospheres used at different time on the regeneration of allogeneic nerve after transplant. METHODS: Single emulsion-solvent evaporation method (O/W) was adopted to prepare the FK506 nanospheres and the tibial nerve of rats after allogeneic transplantation. FK506 nanospheres were used in group A after operation immediately, in group B in 24 h after operation, and in group C in 3 d after operation while FK506 nanospheres were not used in group D; in the 4th, 8th and 12th week after operation respectively, general observation of transplanted nerves, histological examination, image analysis of myelinated fibers, wet-weight determination of musculi triceps surae, retrogradely labeling of neurons by the fluorescein and electrophysiological comparison of bilateral tibial nerve were carried out. RESULTS: FK506 nanospheres can be degraded and absorbed quickly. The neural regenerations in group A and B were similar, which were both much better than those in group C and D. The difference was statistically significant and so was the difference between group C and D. CONCLUSIONS: Drug release rate of FK506 nanospheres is accordant with the regeneration law of damaged nerves and the local application can promote the regenerations of nerves. The effect would be better if the drug is used in earlier period (within 24 h).

Minced nerve tissue in vein grafts used as conduits in rat tibial nerves.

INTRODUCTION: Peripheral nerve injuries are encountered frequently in clinical practice. In nerve repair, an end-to-end suture is the preferable choice of treatment. However, where primary closure is not possible, the defect is to be repaired with a nerve graft. METHODS: A total of 21 female Wistar rats weighing 230 to 290 g were used in the study. They were classified into the following 3 groups: (I) nerve graft, (II) vein graft, and (III) minced nerve graft. In group I, after exposure of the tibial nerve, a 1-cm-long nerve gap was created on the tibial nerve, and the defect was repaired epineurally by using the autogenous nerve. In group II, the 1-cm tibial nerve defect was repaired by using an autogenous vein graft. In group III, a 1-cm nerve graft was divided to 3 equal parts, with one of the nerve parts being minced with microscissors and placed in the vein graft lumen. Thereafter, a 1-cm tibial nerve defect was repaired by the vein graft filled with minced nerve tissue. The tibial function indices (TFIs) were calculated for functional assessment using the Bain-Mackinnon-Hunter formula. Light and electron microscopic evaluations were performed for morphometric assessment. In addition, the myelinated fibers were counted in all groups. RESULTS: The TFIs of group II were found to be the lowest among all the groups after the sixth week, whereas the TFI of group I was found to be better than the other groups after the sixth week. There was no difference in TFIs between group I and group III. On the basis of the number of myelinated fibers, there was no statistically significant difference between group I and group III, whereas the difference was significant (P<0.05) between groups I/III and group II. Presence of peripheral nerves in light microscopic evaluation revealed normal characteristics of myelinated fibers in all groups. The myelinated axon profile was near normal in the nerve graft group in electron microscopic evaluation. However, there were more degenerated axons with disturbed contours and vacuolizations in the vein graft group compared to the minced nerve graft group. CONCLUSIONS: We can conclude that using minced nerve tissue in vein grafts as a conduit increases the regeneration of nerves (almost like the nerve graft group) and it may not be caused by donor-site morbidity. It can be used in the repair of nerve defects instead of autogenous nerve grafts after further experimental evidence and clinical trials.

A gastrocnemius heterotopical transplant model with end-to-side neurorraphy

PURPOSE: To present an animal model to assess the effects of end-to-side innervation in the heterotopically transplanted model with reduced chances of neural contamination. METHODS: The medial portion of the gastrocnemius muscle in wistar male rats was isolated and its pedicle dissected and performed a flap in the abdominal portion. To prevent neural contamination in the abdominal region, the muscle was wrapped with a Goretex(r) sheet. The specimens were divided into 2 groups (G). In G1 was performed an end-to-end suture between tibial nerve of the gastrocnemius and femoral motor nerve and between the saphenous sensory nerve and the motor nerve. In G2 was performed a end-to-side suture between the tibial nerve and the motor femoral and between the tibial nerve and saphenous motor nerve. The specimens were evaluated 60 days later to check the structure of the neurorraphy. Sections were obtained proximal and distal to the coaptation site. RESULTS: The medial gastrocnemius muscle had the advantage of maintaining visible mass after 60 days. No disruption of the coaptation site was found. No major injury to the donor nerve was seen in group 2. CONCLUSION: The proposed model is simple, reproduciple and prevent the neural contamination in the flap in end-to-side suture. .

Clinical results of transferring a motor branch of the tibial nerve to the deep peroneal nerve for treatment of foot drop.

BACKGROUND: Foot drop is a very debilitating condition affecting patients' daily activities, and its treatment has been a challenge for neurosurgeons. Grafting the peroneal or sciatic nerve usually results in poor outcomes. Our previous anatomic study demonstrated the feasibility of transferring a motor branch of the tibial nerve to the deep peroneal nerve at the level of the popliteal fossa. OBJECTIVE: To demonstrate the outcomes obtained after the transfer of a branch of the tibial nerve to the peroneal nerve for recovery of foot drop. METHODS: A retrospective review of 13 patients with foot drop caused by injuries to a lumbar root or the sciatic or peroneal nerve, who underwent a transfer of the nerve of the soleus muscle to the deep peroneal nerve. The results were evaluated using the British Medical Research Council grading system. RESULTS: Three patients were lost to follow-up. Of the remaining 10 patients, the outcomes were considered good (Medical Research Council grade M3 or M4) in 2 patients (20%) concerning ankle dorsiflexion and in 2 patients concerning toe extension (20%). One patient reported a reduced calf circumference. CONCLUSION: The transfer of the nerve of the soleus muscle to the deep peroneal nerve demonstrated poor results in most of the patients, although favorable outcomes were observed in a few subjects. Due to the inconsistency of the results, we do not favor the routine use of this technique for the treatment of foot drop.

Dog tibial nerve regeneration across a 30-mm defect bridged by a PRGD/PDLLA/ß-TCP/NGF sustained-release conduit.

Nerve conduits have emerged as alternatives to autologous nerve grafts, but their use in large-diameter, critical nerve repairs is limited. In the previous study, we prepared a PRGD/PDLLA/ß-TCP/NGF sustained-release nerve conduit, which was made of RGD peptide modified poly{(lactic acid)-co-[(glycolic acid)-alt-(L-lysine)]} (PRGD), poly(d,l-lactic acid) (PDLLA), ß-tricalcium phosphate (ß-TCP) and nerve growth factor (NGF). Here we attempted to use the PRGD/PDLLA/ß-TCP/NGF sustained-release nerve conduit to bridge a 30-mm dog tibial nerve defect in six beagles. The other beagles were divided into group autograft (n = 6) as positive control and group PDLLA (n = 6) as negative control. After 9 months of implantation, nerve conduction velocities, the density of myelinated fibers, the mean diameter of axon, and the average thickness of myelin sheath in tibial nerves bridged with PRGD/PDLLA/ß-TCP/NGF sustained-release nerve conduits were similar to those treated with autologous nerve (p > 0.05). Neither electrophysiological nor histological restoration was obtained in group PDLLA. Evidence is thus provided in support of the use of PRGD/PDLLA/ß-TCP/NGF sustained-release nerve conduits as alternatives to autologous nerve grafts for treatment of large-diameter, critical defects in peripheral nerves.

Muscle reinnervation in one or two stages?: experimental study in rats with end-to-side nerve graft.

PURPOSE: To compare muscle reinnervation in one and two surgical stages using end-to-side neurorrhaphy (ESN) without donor nerve injury. METHODS: The experiment was performed on four groups of 20 rats. Group 1 (G1), one stage, received the graft which was sutured to the tibial nerve, with ESN, and its free stump was sutured end-to-end to the distal stump of the sectioned peroneal nerve (PN), all in the same operation. In Group 2 (G2), two stages, the nerve graft was sutured to the tibial nerve, with ESN. Two months later the PN was sectioned and its distal stump connected to the distal stump of the graft as in G1. Normal control group (Gn) received the graft only sutured to the tibial nerve, with ESN. Denervated control group (Gd), as well received the graft and had the PN sectioned and its two stumps buried in adjacent musculature, with the aim of denervating the cranial tibial muscle (CTM), the target of this study. The parameters used to evaluate CTM reinnervation were muscle mass, muscle fiber's minimum diameter and area. RESULTS: The mean CTM mass, the average of the muscular fibers areas and the average of the muscular fiber minimum diameters was higher (all p<0.0001) in G2 than in G1. Comparing the four groups, these parameters had their maximum expression in Gn and the minimum in Gd, as expected. CONCLUSION: The two stages showed better muscle reinnervation than one stage.

Muscle reinnervation in one or two stages?: experimental study in rats with end-to-side nerve graft / Reinervação muscular em um ou dois estágios?: estudo experimental em ratos com enxerto de nervo término-lateral

PURPOSE: To compare muscle reinnervation in one and two surgical stages using end-to-side neurorrhaphy (ESN) without donor nerve injury. METHODS: The experiment was performed on four groups of 20 rats. Group 1 (G1), one stage, received the graft which was sutured to the tibial nerve, with ESN, and its free stump was sutured end-to-end to the distal stump of the sectioned peroneal nerve (PN), all in the same operation. In Group 2 (G2), two stages, the nerve graft was sutured to the tibial nerve, with ESN. Two months later the PN was sectioned and its distal stump connected to the distal stump of the graft as in G1. Normal control group (Gn) received the graft only sutured to the tibial nerve, with ESN. Denervated control group (Gd), as well received the graft and had the PN sectioned and its two stumps buried in adjacent musculature, with the aim of denervating the cranial tibial muscle (CTM), the target of this study. The parameters used to evaluate CTM reinnervation were muscle mass, muscle fiber's minimum diameter and area. RESULTS: The mean CTM mass, the average of the muscular fibers areas and the average of the muscular fiber minimum diameters was higher (all p<0.0001) in G2 than in G1. Comparing the four groups, these parameters had their maximum expression in Gn and the minimum in Gd, as expected. CONCLUSION: The two stages showed better muscle reinnervation than one stage.

OBJETIVO: Comparar a reinervação muscular com enxerto de nervo em um e dois tempos operatórios, utilizando a neurorrafia término-lateral (NTL) sem lesão do nervo doador. MÉTODOS: Vinte ratos foram distribuídos em quatro grupos. O grupo 1 (G1), um estágio, recebeu o enxerto que foi suturado ao nervo tibial (NT), por meio de NTL, e seu coto livre foi suturado por NTL ao coto distal do nervo peroneal (NP), seccionado a um centímetro do NT, na mesma cirurgia. O grupo 2 (G2), dois estágios, recebeu o enxerto de nervo na primeira cirurgia, como já descrito. Dois meses depois, na segunda cirurgia, o NP foi seccionado e seu coto distal ligado ao coto distal do enxerto como em G1. O grupo controle de normalidade (Gn) recebeu o enxerto da mesma forma, apenas. E o grupo controle de denervação (Gd), além de receber o enxerto, teve o NP seccionado e seus cotos sepultados na musculatura adjacente, com a finalidade de denervar o músculo tibial cranial (MTC), alvo deste estudo. Os parâmetros utilizados para avaliar a reinervação do MTC foram massa muscular, diâmetro mínimo da fibra muscular e área. RESULTADOS: O grupo G2 apresentou superioridade (p<0,0001) em relação ao G1 na massa do MTC, no diâmetro mínimo e na área das fibras musculares. Na comparação entre os quatro grupos, estes mesmos parâmetros tiveram sua expressão máxima em Gn e mínima em Gd, como era esperado. CONCLUSÃO: A reinervação muscular em dois estágios apresenta melhor resultado quando comparada à técnica em um tempo.

Surgical technique of a partial tibial nerve transfer to the tibialis anterior motor branch for the treatment of peroneal nerve injury.

Injuries to the common peroneal nerve can be functionally debilitating with few treatment options. Traditionally, tendon transfers and ankle-foot orthotics have been the standard treatment of foot drop with satisfactory patient outcomes. The purpose of this manuscript is to describe an alternative surgical technique option to obtain ankle dorsiflexion in patients with foot drop using a partial nerve transfer from the tibial nerve to the motor branch of the tibialis anterior.

The embracing end-to-side neurorrhaphy in rats.

PURPOSE: Compare two new methods with the traditional end-to-side neurorrhaphy. METHODS: Rats were divided into four groups. In A-L group the peroneal nerve was sectioned and the distal stump was connected to the lateral of the tibial nerve (donor) with two 10-0 nylon points. In A-R group two perineurium flaps embraced the donor nerve. In the B-R group a suture embraced the donor nerve. Group B-L was the control. After six months tibial cranial muscle mass and morphometry of the distal stump of the peroneal nerve were evaluated. RESULTS: Muscle mass in groups A-R, A-L and B-R were lower than B-L group (p<0.0001) an equal between themselves (p>0.05). Groups A-R, B-R and A-L had a lower number of nerve fibers when compared with B-L (p=0.0155, p=0.016, p=0.0021). CONCLUSION: The three types of neurorrhaphy showed no differences related to muscle mass and number of nerve fibers suggesting that the embracing with a single suture has great potential due its simplicity and usefulness in deep areas.

The embracing end-to-side neurorrhaphy in rats / A neurorrafia término-lateral abraçante em ratos

PURPOSE: Compare two new methods with the traditional end-to-side neurorrhaphy. METHODS: Rats were divided into four groups. In A-L group the peroneal nerve was sectioned and the distal stump was connected to the lateral of the tibial nerve (donor) with two 10-0 nylon points. In A-R group two perineurium flaps embraced the donor nerve. In the B-R group a suture embraced the donor nerve. Group B-L was the control. After six months tibial cranial muscle mass and morphometry of the distal stump of the peroneal nerve were evaluated. RESULTS: Muscle mass in groups A-R, A-L and B-R were lower than B-L group (p<0.0001) an equal between themselves (p>0.05). Groups A-R, B-R and A-L had a lower number of nerve fibers when compared with B-L (p=0.0155, p=0.016, p=0.0021). CONCLUSION: The three types of neurorrhaphy showed no differences related to muscle mass and number of nerve fibers suggesting that the embracing with a single suture has great potential due its simplicity and usefulness in deep areas.

OBJETIVO: Comparar dois novos métodos com o método tradicional da neurorrafia término-lateral. MÉTODOS: Os ratos foram separados em quatro grupos. No grupo A-E o nervo peroneal foi seccionado e o coto distal foi suturado à lateral do nervo tibial com dois pontos de nylon 10-0. No grupo A-D duas abas de epi-perineuro abraçaram o nervo doador. No grupo B-D foi realizada sutura com um único ponto abraçando o nervo doador. O grupo B-E foi o controle. Após seis meses foram observados massa do músculo tibial cranial e morfometria do coto distal do nervo peroneal. RESULTADOS: Foi encontrada menor massa muscular nos grupos A-D, A-E e B-D quando comparados com o grupo B-E (p<0.0001) e mesma massa quando comparados entre si (p>0,05). Os grupos A-D, A-E e B-D apresentaram menor número de fibras nervosas quando comparados ao grupo B-E (p=0,0155; p=0,016; p=0,0021) e mesmo número quando comparados entre si. CONCLUSÃO: Os três tipos de neurorrafia não apresentaram diferenças relacionadas à massa muscular e número de fibras nervosas sugerindo que a sutura abraçante com apenas um ponto apresente grande potencial em áreas cirúrgicas mais profundas.