The distance between the fibular collateral ligament tunnel and the common peroneal nerve allows a posterolateral corner reconstruction without neurolysis.

PURPOSE: The most popular knee posterolateral corner (PLC) reconstruction techniques describe that a common peroneal nerve (CPN) neurolysis must be done to safely address the posterolateral aspect of the knee. The purpose of this study was to measure the distance between the CPN and the fibular insertion of the FCL in different degrees of knee flexion in cadaveric specimens, to identify if tunnel drilling could be done anatomically and safely without a CPN neurolysis. METHODS: Ex vivo experimental analytical study. Ten fresh frozen human knees were dissected leaving FCL and CPN in situ. Shortest distance from the centre of the FCL distal tunnel and CPN was measured (antero-posterior and proximal-distal wire-nerve distances) at 90°, 60°, 30°, and 0° of knee flexion. Measurements between different flexion angles were compared and correlation between knee flexion angle and distance was identified. RESULTS: The mean distance between the FCL tunnel and the CPN at 90° were 21.15 ± 6.74 mm posteriorly (95% CI: 16.33-25.97) and 13.01 ± 3.55 mm distally (95% CI: 10.47-15.55). The minimum values were 9.8 mm posteriorly and 8.9 mm, respectively. These distances were smaller at 0° (p ≤ 0.017). At 90° of knee flexion, the mean distance from the fibular tip to the CPN distally was 23.46 ± 4.13 mm (20.51-26.41). CONCLUSION: Anatomic localization and orientation of fibular tunnels can be done safely while avoiding nerve neurolysis. Further studies should aim to in vivo measurements and results.

Neuropathic pain in peroneal nerve entrapment at the fibular head / Dor neuropática no aprisionamento do nervo fibular na cabeça da fíbula

Abstract Background Peroneal neuropathy at the fibular head (PNFH) is a mononeuropathy that typically presents with drop foot and sensory abnormalities over the skin area innervated by the peroneal nerve. Objective The aim of the present study was to evaluate neuropathic pain in patients with PNFH. Methods Patients with clinical and electrodiagnostic features consistent with PNFH associated with weight loss, leg postures, or prolonged sleep were included in the present retrospective cohort study. Nerve conduction studies were performed in the bilateral lower extremities of all patients. The Leeds assessment of neuropathic symptoms and signs scale (LANSS) was applied to all patients. Results Thirty-two PNFH patients (78% males) were included in the study. The LANSS score in the majority of patients was lower than 12. There was 1 patient with a LANSS score of 12. The electrodiagnostic features of 16 patients were compatible with axonal degeneration. The mean LANSS scores of PNFH patients with and without axonal degeneration were 4.3 ± 3.7 and 5.2 ± 2.9, respectively (p = 0.255). Conclusion The present study showed that neuropathic pain is a rare symptom in patients with PNFH associated with weight loss, leg postures, or prolonged sleep.

Resumo Antecedentes A neuropatia fibular na cabeça da fíbula (PNFH) é uma mononeuropatia que normalmente se apresenta com pé caído e anormalidades sensoriais sobre a área da pele inervada pelo nervo fibular. Objetivo O objetivo do presente estudo foi avaliar a dor neuropática em pacientes com PNFH. Métodos Pacientes com características clínicas e eletrodiagnósticas consistentes com PNFH associada a perda de peso, postura das pernas ou sono prolongado foram incluídos neste estudo de coorte retrospectivo. Estudos de condução nervosa foram realizados nas extremidades inferiores bilaterais de todos os pacientes. A escala de avaliação de sintomas e sinais neuropáticos de Leeds (LANSS) foi aplicada a todos os pacientes. Resultados Trinta e dois pacientes com PNFH (78%) foram incluídos no estudo. A pontuação LANSS em outros pacientes foi menor que 12. Houve 1 paciente com pontuação LANSS de 12. As características eletrodiagnósticas de 16 pacientes foram compatíveis com degeneração axonal. Os escores médios do LANSS de pacientes com PNFH com e sem degeneração axonal foram 4,3 ± 3,7 e 5,2 ± 2,9, respectivamente (p = 0,255). Conclusão O presente estudo mostrou que a dor neuropática é um sintoma raro em pacientes com PNFH associada à perda de peso, postura das pernas ou sono prolongado.

Transferencia tendinosa del tibial posterior en pie caído por lesión del nervio peroneo común / Tendon transfer of the posterior tibial in fallen foot due to lesion of the common peroneal nerve i:en

Se describe el caso clínico de un paciente de 34 años de edad, con antecedente de salud, atendido en la consulta intermunicipal de II Frente, provincia de Santiago de Cuba, por presentar, desde hacía 8 meses, una lesión en el nervio peroneo común, en la cara lateral del tercio superior de la pierna derecha, a causa de una mordida de cerdo, la cual no fue diagnosticada inicialmente, sino que se trató como una herida sin lesión neurológica. Se realizó proceder quirúrgico, consistente en una transposición tendinosa del músculo tibial posterior. Se inmovilizó el pie con una férula de yeso por 15 días, se le retiró la sutura a las 6 semanas y se indicó rehabilitación. A las 12 semanas comenzó a caminar sin dificultad y logró reincorporarse a sus actividades cotidianas.

The case report of a 34 years patient with health history is described. He was assisted in the intermunicipal visit of II Frente, province of Santiago de Cuba, due to a lesion in the common peroneal nerve during 8 months, in the lateral face of the superior third of the right leg, because of a pig bite, which was not diagnosed initially, but instead it was treated as a wound without neurological lesion. A surgical procedure was carried out, with a tendon transposition of the posterior tibial muscle. The foot was immobilized with a plaster splint for 15 days, the suture was removed 6 weeks later and rehabilitation was indicated. Twelve weeks later he began to walk without difficulty and he was able to return to his daily activities.

Very low peroneal nerve compound muscle action potential amplitude predicts poor outcome in patients with Guillain-Barré syndrome: a prospective cohort.

INTRODUCTION: Twenty percent of patients with Guillain-Barré syndrome (GBS) have poor outcomes despite proper management. The aim of the study was to characterize electrophysiological factors related to poor outcome in patients with GBS. METHODS: We conducted an observational study from a prospective cohort of 91 patients with GBS in a tertiary healthcare center in Mexico, from 2017 to 2019. Demographics and nerve conduction studies were performed on admission, and a 3-month follow-up for GBS disability score was ensued, allocating patients in good (GBS disability score ≤ 2) and poor outcome (GBS disability score ≥ 3) groups. A logistic regression analysis for independent walk at 3 months was performed. Kaplan-Meier estimator curves for independent walk in very low (< 20% LLN) and low-normal ( ≥20% LLN) peroneal nerve CMAPs are presented. RESULTS: From the 91 GBS patients included, 37 (40.6%) did not regain independent walk at 3 months. Axonal variants were more common in the poor outcome group (31.4% vs 59.4%, p = 0.01) as well as AIDP variants with motor conduction block (6.6% vs 42.4%, p = 0.018). Univariable analysis was statistically significant for very low median, ulnar, tibial, and peroneal CMAP amplitudes in poor outcome patients; however, multivariable analysis was only significant for very low peroneal nerve CMAP amplitude (OR 3.6 [1.1-11.5, p = 0.024]). Conversely, a greater proportion of GBS patients with low-normal CMAPs recovered independent walk at 90 days (75% vs 30%, p < 0.001). CONCLUSION: Severe axonal injury of the peroneal nerve, axonal, and AIDP with motor conduction block variants predicts worse functional outcome regarding independent walk at 3 months.

Magnetic resonance imaging evaluation of common peroneal nerve injury in acute and subacute posterolateral corner lesion: a retrospective study.

OBJECTIVE: To evaluate qualitative and quantitative magnetic resonance imaging (MRI) criteria for injury of the common peroneal nerve (CPN) in patients with acute or subacute injuries in the posterolateral corner (PLC) of the knee, as well as to evaluate the reproducibility of MRI evaluation of CPN alterations. MATERIALS AND METHODS: This was a retrospective study of 38 consecutive patients submitted to MRI and diagnosed with acute or subacute injury to the PLC of the knee (patient group) and 38 patients with normal MRI results (control group). Two musculoskeletal radiologists (designated radiologist A and radiologist B, respectively) evaluated the images. Nerve injury was classified as neurapraxia, axonotmesis, or neurotmesis. Signal strength was measured at the CPN, the tibial nerve (TN), and a superficial vein (SV). The CPN/TN and CPN/SV signal ratios were calculated. The status of each PLC structure, including the popliteal tendon, arcuate ligament, lateral collateral ligament, and biceps tendon, was classified as normal, partially torn, or completely torn, as was that of the cruciate ligaments. For the semiquantitative analysis of interobserver agreement, the kappa statistic was calculated, whereas a receiver operating characteristic (ROC) curve was used for the quantitative analysis. RESULTS: In the patient group, radiologist A found CPN abnormalities in 15 cases (39.4%)-neurapraxia in eight and axonotmesis in seven-whereas radiologist B found CPN abnormalities in 14 (36.8%)-neurapraxia in nine and axonotmesis in five. The kappa statistic showed excellent interobserver agreement. In the control group, the CPN/TN signal ratio ranged from 0.63 to 1.1 and the CPN/SV signal ratio ranged from 0.16 to 0.41, compared with 1.30-4.02 and 0.27-1.08, respectively, in the patient group. The ROC curve analysis demonstrated that the CPN/TN signal ratio at a cutoff value of 1.39 had high (93.3%) specificity for the identification of nerve damage, compared with 81.3% for the CPN/SV signal ratio at a cutoff value of 0.41. CONCLUSION: CPN alterations are common in patients with PLC injury detected on MRI, and the level of interobserver agreement for such alterations was excellent. Calculating the CPN/TN and CPN/SV signal ratios may increase diagnostic confidence. We recommend systematic analysis of the CPN in cases of PLC injury.

OBJETIVO: Avaliar critérios de identificação de lesão no nervo fibular comum (NFC) por ressonância magnética (RM) em pacientes com lesão aguda e subaguda no canto posterolateral (CPL) e avaliar a reprodutibilidade na identificação de alterações do NFC. MATERIAIS E MÉTODOS: Foram incluídos, retrospectivamente, 38 pacientes consecutivos submetidos a RM e com diagnóstico de lesão aguda ou subaguda no CPL do joelho, constituindo o grupo de pacientes. Outros 38 pacientes com RM normal foram utilizados como grupo controle. Dois radiologistas musculoesqueléticos (A e B) analisaram as imagens. A lesão neural foi classificada em neuropraxia, axoniotmese ou neurotmese. Foi medida a intensidade do sinal no NFC, no nervo tibial (NT) e em uma veia superficial (VS), e calculadas as razões de sinal NFC/NT e NFC/VS. Estruturas do CPL, incluindo tendão poplíteo, ligamento arqueado, ligamento colateral lateral e tendão do bíceps, foram classificadas como normal, rotura parcial ou rotura completa. Os ligamentos cruzados também foram avaliados segundo os mesmos critérios. O teste kappa foi utilizado para avaliar a concordância interobservador para as classificações semiquantitativas. Curva ROC foi utilizada para análise quantitativa. RESULTADOS: O radiologista A encontrou alterações no NFC em 15 casos (39,4%): 8 neuropraxias, 7 axoniotmeses e nenhuma neurotmese. O radiologista B encontrou alterações no NFC em 14 casos (36,8%): 9 neuropraxias, 5 axoniotmeses e nenhuma neurotmese. O teste kappa mostrou alta concordância interobservador. No grupo controle, a razão NFC/NT variou entre 0,63-1,1 e a razão NFC/VS variou entre 0,16-0,41. Para o grupo de pacientes, a razão NFC/NT variou entre 1,30-4,02 e a razão NFC/VS variou entre 0,27-1,08. A análise com curva ROC demonstrou alta especificidade (93,3%) com relação à razão NFC/NT, usando um valor de corte de 1,39. Houve boa especificidade (81,3%) para a razão NFC/VS usando um valor de corte de 0,41. CONCLUSÃO: As alterações do NFC são detectadas com frequência nas lesões do CPL nas imagens de RM, com concordância interobservadores quase perfeita. Usando as razões de intensidade de sinal entre o NFC e o NT e entre o NFC e a VS, aumenta a confiança no diagnóstico. Recomendamos a análise sistemática do NFC nos casos de lesão do CPL.

Magnetic resonance imaging evaluation of common peroneal nerve injury in acute and subacute posterolateral corner lesion: a retrospective study / Estudo retrospectivo das alterações do nervo fibular comum identificadas por ressonância magnética nas lesões agudas e subagudas do canto posterolateral do joelho

Abstract Objective: To evaluate qualitative and quantitative magnetic resonance imaging (MRI) criteria for injury of the common peroneal nerve (CPN) in patients with acute or subacute injuries in the posterolateral corner (PLC) of the knee, as well as to evaluate the reproducibility of MRI evaluation of CPN alterations. Materials and Methods: This was a retrospective study of 38 consecutive patients submitted to MRI and diagnosed with acute or subacute injury to the PLC of the knee (patient group) and 38 patients with normal MRI results (control group). Two musculoskeletal radiologists (designated radiologist A and radiologist B, respectively) evaluated the images. Nerve injury was classified as neurapraxia, axonotmesis, or neurotmesis. Signal strength was measured at the CPN, the tibial nerve (TN), and a superficial vein (SV). The CPN/TN and CPN/SV signal ratios were calculated. The status of each PLC structure, including the popliteal tendon, arcuate ligament, lateral collateral ligament, and biceps tendon, was classified as normal, partially torn, or completely torn, as was that of the cruciate ligaments. For the semiquantitative analysis of interobserver agreement, the kappa statistic was calculated, whereas a receiver operating characteristic (ROC) curve was used for the quantitative analysis. Results: In the patient group, radiologist A found CPN abnormalities in 15 cases (39.4%)-neurapraxia in eight and axonotmesis in seven-whereas radiologist B found CPN abnormalities in 14 (36.8%)-neurapraxia in nine and axonotmesis in five. The kappa statistic showed excellent interobserver agreement. In the control group, the CPN/TN signal ratio ranged from 0.63 to 1.1 and the CPN/SV signal ratio ranged from 0.16 to 0.41, compared with 1.30-4.02 and 0.27-1.08, respectively, in the patient group. The ROC curve analysis demonstrated that the CPN/TN signal ratio at a cutoff value of 1.39 had high (93.3%) specificity for the identification of nerve damage, compared with 81.3% for the CPN/SV signal ratio at a cutoff value of 0.41. Conclusion: CPN alterations are common in patients with PLC injury detected on MRI, and the level of interobserver agreement for such alterations was excellent. Calculating the CPN/TN and CPN/SV signal ratios may increase diagnostic confidence. We recommend systematic analysis of the CPN in cases of PLC injury.

Resumo Objetivo: Avaliar critérios de identificação de lesão no nervo fibular comum (NFC) por ressonância magnética (RM) em pacientes com lesão aguda e subaguda no canto posterolateral (CPL) e avaliar a reprodutibilidade na identificação de alterações do NFC. Materiais e Métodos: Foram incluídos, retrospectivamente, 38 pacientes consecutivos submetidos a RM e com diagnóstico de lesão aguda ou subaguda no CPL do joelho, constituindo o grupo de pacientes. Outros 38 pacientes com RM normal foram utilizados como grupo controle. Dois radiologistas musculoesqueléticos (A e B) analisaram as imagens. A lesão neural foi classificada em neuropraxia, axoniotmese ou neurotmese. Foi medida a intensidade do sinal no NFC, no nervo tibial (NT) e em uma veia superficial (VS), e calculadas as razões de sinal NFC/NT e NFC/VS. Estruturas do CPL, incluindo tendão poplíteo, ligamento arqueado, ligamento colateral lateral e tendão do bíceps, foram classificadas como normal, rotura parcial ou rotura completa. Os ligamentos cruzados também foram avaliados segundo os mesmos critérios. O teste kappa foi utilizado para avaliar a concordância interobservador para as classificações semiquantitativas. Curva ROC foi utilizada para análise quantitativa. Resultados: O radiologista A encontrou alterações no NFC em 15 casos (39,4%): 8 neuropraxias, 7 axoniotmeses e nenhuma neurotmese. O radiologista B encontrou alterações no NFC em 14 casos (36,8%): 9 neuropraxias, 5 axoniotmeses e nenhuma neurotmese. O teste kappa mostrou alta concordância interobservador. No grupo controle, a razão NFC/NT variou entre 0,63-1,1 e a razão NFC/VS variou entre 0,16-0,41. Para o grupo de pacientes, a razão NFC/NT variou entre 1,30-4,02 e a razão NFC/VS variou entre 0,27-1,08. A análise com curva ROC demonstrou alta especificidade (93,3%) com relação à razão NFC/NT, usando um valor de corte de 1,39. Houve boa especificidade (81,3%) para a razão NFC/VS usando um valor de corte de 0,41. Conclusão: As alterações do NFC são detectadas com frequência nas lesões do CPL nas imagens de RM, com concordância interobservadores quase perfeita. Usando as razões de intensidade de sinal entre o NFC e o NT e entre o NFC e a VS, aumenta a confiança no diagnóstico. Recomendamos a análise sistemática do NFC nos casos de lesão do CPL.

Lower extremity nerve injuries and their management at a referral center in Mexico City.

OBJETIVO: Describir el manejo de las lesiones nerviosas de extremidad inferior atendidas en un centro de referencia en cirugía plástica y reconstructiva en la Ciudad de México. MÉTODO: Estudio descriptivo, transversal y retrospectivo, en el que se evaluaron los expedientes clínicos de pacientes atendidos por lesiones nerviosas de extremidad inferior entre 2010 y 2018. RESULTADOS: Se incluyeron 21 pacientes, 14 hombres (66.6%) y 7 mujeres (33.3%), con una edad promedio de 30.00 ± 8.89 años. Las lesiones en la extremidad derecha fueron más prevalentes (52.3%). El mecanismo de lesión más común fue por herida por proyectil de arma de fuego (28.5%) o por accidente automovilístico (13.6%). Los nervios más afectados fueron el ciático (38.0%) y el peroneo (38.0%), seguidos por el tibial (9.5%), el peroneo y el tibial simultáneamente (9.5%) y el femoral (4.7%). Las medidas de tratamiento más empleadas fueron las transferencias nerviosas (7 casos, 33.3%) y la aplicación de injertos nerviosos para el manejo de brechas (7 casos, 33.3%). CONCLUSIONES: La reparación de las estructuras nerviosas de la extremidad inferior ha recibido poca atención. Sin embargo, nuestro estudio muestra que es posible aplicar diversas estrategias reconstructivas microquirúrgicas, buscando mejorar los desenlaces funcionales de los pacientes. OBJECTIVE: To describe the management of lower extremity nerve injuries at a plastic and reconstructive surgery referral center in Mexico City. METHOD: A descriptive, transversal and retrospective study was performed, evaluating clinical records of patients with lower extremity nerve injuries managed in our center between 2010 and 2018. RESULTS: Twenty-one patients were included, 14 males (66.6%) and 7 females (33.3%); mean age was 30.00 ± 8.89 years. Right-sided injuries were more prevalent (52.3%). The most common etiologies were gunshot injuries (28.5%) and motor vehicle accidents (13.6%). The most frequently affected nerves were the sciatic (38.0%) and the peroneal nerves (38.0%), followed by the tibial (9.5%), simultaneous tibial and peroneal nerve injury (9.5%) and the femoral nerve (4.7%). Nerve transfers (7 cases, 33.3%) and autologous nerve grafts (7 cases, 33.3%) were the preferred surgical techniques for injury management. CONCLUSIONS: Repair of lower extremity nerve injuries has not been popularized, however our study shows that several microsurgical reconstructive strategies are available in order to improve functional outcomes.

Eficácia da estimulação elétrica com corrente russa após neurorrafia término-lateral do nervo fibular comum: análise eletroneuromiográfica e de força muscular / Eficacia de la estimulación eléctrica con la corriente rusa tras la neurorrafia término-lateral del nervio fibular común: análisis electroneuromiográfico y de fuerza muscular muscular / Efficacy of electrical Russian current stimulation after end-to-side neurorrhaphy of the common fibular nerve: electroneuromyography and muscle strength analysis

RESUMO Lesões de nervos periféricos levam a perda funcional elevada no tecido muscular. Assim, muitas pesquisas têm investigado técnicas cirúrgicas, como neurorrafias, e recursos terapêuticos, como eletroestimulação, para melhorar a funcionalidade de um músculo reinervado após lesão periférica. Este estudo tem como objetivo investigar os efeitos da eletroestimulação com corrente russa (2.500Hz, 4ms, 10 seg. de contração por 20 seg. de relaxamento, modulação de 10Hz e 100 Hz) na recuperação funcional após secção e neurorrafia término-lateral do coto distal do nervo fibular comum à face lateral do nervo tibial em ratos. Foram utilizados 25 ratos Wistar, machos, com 80 dias de vida, fornecidos pelo Biotério Central da Universidade Sagrado Coração (Bauru, SP, Brasil). Os animais foram divididos aleatoriamente em cinco grupos: grupo-controle Inicial (GCI), grupo-controle final (GCF), grupo experimental não tratado (GENT), grupo neurorrafia término-lateral com estimulação russa (GNTLER) e grupo-controle desnervado (GCD). A corrente russa foi iniciada cinco dias após neurorrafia e aplicada no músculo tibial cranial do GNTLER, 3 vezes por semana, totalizando 36 sessões. A estimulação elétrica foi eficaz para aumentar a amplitude e diminuir a latência do músculo reinervado, além de aumentar a força muscular em comparação ao GCD. Diante disso, conclui-se que a eletroestimulação de média frequência (corrente russa) foi eficiente na recuperação funcional do músculo tibial cranial após neurorrafia término-lateral do nervo fibular comum.

RESUMEN Las lesiones de los nervios periféricos ocasionan una elevada pérdida funcional en el tejido muscular. De esta manera, en muchos estudios se han investigado técnicas quirúrgicas, como neurorrafias, y recursos terapéuticos, como la electroestimulación, para mejorar la funcionalidad del músculo reinervado tras una lesión periférica. El presente estudio tiene como objetivo investigar los efectos de la electroestimulación con corrente rusa (2.500Hz, 4ms, 10 seg. de contracción por 20 seg. de relajación, modulación de 10Hz y 100Hz) en la recuperación funcional tras la sección y neurorrafia término-lateral del muñón distal del nervio fibular común en la parte lateral del nervio tibial en ratas. Se utilizaron 25 ratas Wistar, machos, con 80 días de vida, proporcionadas por el Biotério Central de la Universidade do Sagrado Coração (Bauru, SP, Brasil). Se dividieron aleatoriamente los animales en cinco grupos: grupo de control inicial (GCI), grupo de control final (GCF), grupo experimental no tratado (GENT), grupo de neurorrafia término-lateral con estimulación rusa (GNTLER) y grupo de control denervado (GCD). La corriente rusa se inició cinco días tras la neurorrafia, siendo que la aplicó al músculo tibial craneal del GNTLER 3 veces a la semana, con un total de 36 sesiones. La estimulación eléctrica se mostró efectiva para aumentar la amplitud y disminuir la latencia del músculo reinervado, además de aumentar la fuerza muscular en comparación con el GCD. Por lo tanto, se concluye que la estimulación eléctrica de frecuencia media (corriente rusa) fue eficaz en la recuperación funcional del músculo tibial craneal tras la neurorrafia término-lateral del nervio fibular común.

ABSTRACT Peripheral nerve injury leads to a high functional loss of muscle tissue. Thus, many studies have investigated surgical techniques, such as neurorraphies, and therapeutic resources, such as electrical stimulation, to improve the functionality of reinnervated muscle after peripheral injury. This study aims to investigate the effects of electrical stimulation with Russian Current (2,500Hz, 4ms, 10:20 sec contraction/relaxation, modulated at 10Hz and 100Hz) in the functional recovery after section and end-to-side neurorrhaphy of the peroneal nerve distal stump common to the lateral face of the tibial nerve in rats. In this study, 25 male Wistar rats with 80 days of life were used, provided by the Universidade Sagrado Coração (USC), Bauru, SP, Brazil. The animals were randomly divided into five groups: Initial Control Group (ICG), Final Control Group (FCG), Untreated Experimental Group (UEG), End-to-Side Neurorrhaphy with Russian Stimulation Group (ENRSG), and Denervated Control Group (DCG). The Russian Current was started 5 days after neurorrhaphy and applied to the cranial tibial muscle of the ENRSG, 3 times a week, totaling 36 sessions. We observed that the electrical stimulation with Russian Current (ENRSG) was effective to increase amplitude (mV) and to decrease the latency (ms) of the reinnervated muscle, besides increasing the muscle strength when compared with the denervated control group. Therefore, we concluded that the average frequency electrical stimulation (Russian current) was efficient in the functional recovery of the cranial tibial muscle after the end-lateral neurorrhaphy of the common fibular nerve.

A rapidly progressive foot drop caused by the posttraumatic Intraneural ganglion cyst of the deep peroneal nerve.

BACKGROUND: Intraneural ganglion cysts usually arise from the articular branch of the nerve. The relationship between intraneural ganglion cysts and trauma is not clear. CASE PRESENTATION: We report a case of a 62-year-old female with a rapidly progressive foot drop caused by a posttraumatic intraneural ganglion cyst of the deep peroneal nerve. We excised the ganglion cyst and performed nerve decompression. After the surgery, the patient had a functional recovery. CONCLUSIONS: The concurrence of an intraneural ganglion cyst and trauma may increase damage to the nerve, although it is difficult to diagnosis before an operation. Early diagnosis and early proactive interventions would likely be associated with a good outcome.

Intraneural perineuriomas: diagnostic value of magnetic resonance neurography.

Intraneural perineurioma (IP) is an under-recognized hypertrophic peripheral nerve tumor. It affects young patients involving frequently the sciatic nerve and its branches and presents with a progressive, painless and predominantly motor deficit. Magnetic resonance neurography (MRN) is a useful tool to localize the lesion, evaluate its extension, and discriminate between different etiologies. We reviewed the clinical records of 11 patients with pathologically confirm IP. Eight patients were males with mean age 19 years. Initial complains were unilateral steppage (seven patients), bilateral steppage (one patient), unilateral gastrocnemius wasting (one patient), unilateral thigh atrophy (one patient), and unilateral hand weakness (one patient). Nine patients had mild painless sensory loss. Examinations revealed involvement of sciatic nerve extending into the peroneal nerve (eight patients), posterior tibial nerve (one patient), radial nerve (one patient), and femoral nerve (one patient). MRN revealed enlargement of the affected nerve isointense on T1-weighted, hyperintense on T2 fat-saturated images, and with avid enhancement on post-contrast imaging. In all patients, a nerve biopsy confirmed the diagnosis. MRN allows early and non-invasive identification of this tumor and is a key tool providing localization and differential diagnosis in patients with slowly progressive focal neuropathies.

End-to-side versus end-to-end neurorrhaphy at the peroneal nerve in rats

Purpose: To evaluate three different kinds of neurorrhaphy of the peroneal nerve. Methods: Eigthy rats were divided into 5 groups. Control: nerve had no intervention. End-to-end (EE): nerve was cut and elongated with a nerve graft with two end-to-end neurorrhaphies. End-to-side (ES): nerve was cut and sutured to the graft with at the lateral side of the nerve. Side-to-end (SE): the nerve was cut and sutured to the graft with end-to-end neurorrhaphy. Denervated: nerve was cut and both endings were buried into the muscle. The evaluation was done by walking track analysis, electrophysiology, body mass, cranial tibial muscle mass, nerve and muscle fibers morphometry. Results: The EE, ES and SE have the same potential of reinnervation. Conclusion: There is no functional or histological difference between these different types of neurorrhaphy.(AU)

End-to-side versus end-to-end neurorrhaphy at the peroneal nerve in rats

Abstract Purpose: To evaluate three different kinds of neurorrhaphy of the peroneal nerve. Methods: Eigthy rats were divided into 5 groups. Control: nerve had no intervention. End-to-end (EE): nerve was cut and elongated with a nerve graft with two end-to-end neurorrhaphies. End-to-side (ES): nerve was cut and sutured to the graft with at the lateral side of the nerve. Side-to-end (SE): the nerve was cut and sutured to the graft with end-to-end neurorrhaphy. Denervated: nerve was cut and both endings were buried into the muscle. The evaluation was done by walking track analysis, electrophysiology, body mass, cranial tibial muscle mass, nerve and muscle fibers morphometry. Results: The EE, ES and SE have the same potential of reinnervation. Conclusion: There is no functional or histological difference between these different types of neurorrhaphy.

Complications and outcomes of the transfibular approach for posterolateral fractures of the tibial plateau.

OBJECTIVE: Evaluate complication rates and functional outcomes of fibular neck osteotomy for posterolateral tibial plateau fractures. DESIGN: Retrospective case series. SETTING: University hospital. PATIENTS: From January 2013 to October 2014, 11 patients underwent transfibular approach for posterolateral fractures of the tibial plateau and were enrolled in the study. All patients who underwent transfibular approach were invited the return to the hospital for another clinical and imaging evaluation. INTERVENTION: Transfibular approach (fibular neck osteotomy) with open reduction and internal fixation for posterolateral fractures of the tibial plateau. MAIN OUTCOME MEASUREMENTS: Complications exclusively related to the transfibular approach: peroneal nerve palsy; knee instability; loss of reduction; nonunion and malunion of fibular osteotomy; and functional outcomes related to knee function. RESULTS: Two patients failed to follow-up and were excluded from the study. Of the 9 patients included in the study, no patients demonstrated evidence of a peroneal nerve palsy. One patient presented loss of fracture reduction and fixation of the fibular neck osteotomy, requiring revision screw fixation. There were no malunions of the fibular osteotomy. None of the patients demonstrated clinically detectable posterolateral instability of the knee following surgery. American Knee Society Score was good in 7 patients (77.8%), fair in 1 (11.1%), and poor in 1 (11.1%). American Knee Society Score/Function showed 80 points average (60-100, S.D:11). CONCLUSION: The transfibular approach for posterolateral fractures is safe and useful for visualizing posterolateral articular injury. The surgeon must gently protect the peroneal nerve during the entire procedure and fix the osteotomy with long screws to prevent loss of reduction. LEVEL OF EVIDENCE: Therapeutic level IV.

Tibial and fibular nerves evaluation using intraoperative electromyography in rats

ABSTRACT PURPOSE: To evaluate a new model of intraoperative electromyographic (EMG) assessment of the tibial and fibular nerves, and its respectives motor units in rats. METHODS: Eight Wistar rats underwent intraoperative EMG on both hind limbs at two different moments: week 0 and week 12. Supramaximal electrical stimulation applied on sciatic nerve, and compound muscle action potential recorded on the gastrocnemius muscle (GM) and the extensor digitorum longus muscle (EDLM) through electrodes at specifics points. Motor function assessment was performaced through Walking Track Test. RESULTS: Exposing the muscles and nerves for examination did not alter tibial (p=0.918) or fibular (p=0.877) function between the evaluation moments. Electromyography of the GM, innervated by the tibial nerve, revealed similar amplitude (p=0.069) and latency (p=0.256) at week 0 and at 12 weeks, creating a standard of normality. Meanwhile, electromyography of the EDLM, innervated by the fibular nerve, showed significant differences between the amplitudes (p=0.003) and latencies (p=0.021) at the two different moments of observation. CONCLUSION: Intraoperative electromyography determined and quantified gastrocnemius muscle motor unit integrity, innervated by tibial nerve. Although this study was not useful to, objectively, assess extensor digitorum longus muscle motor unit, innervated by fibular nerve.

Tibial and fibular nerves evaluation using intraoperative electromyography in rats

PURPOSE:To evaluate a new model of intraoperative electromyographic (EMG) assessment of the tibial and fibular nerves, and its respectives motor units in rats.METHODS:Eight Wistar rats underwent intraoperative EMG on both hind limbs at two different moments: week 0 and week 12. Supramaximal electrical stimulation applied on sciatic nerve, and compound muscle action potential recorded on the gastrocnemius muscle (GM) and the extensor digitorum longus muscle (EDLM) through electrodes at specifics points. Motor function assessment was performaced through Walking Track Test.RESULTS:Exposing the muscles and nerves for examination did not alter tibial (p=0.918) or fibular (p=0.877) function between the evaluation moments. Electromyography of the GM, innervated by the tibial nerve, revealed similar amplitude (p=0.069) and latency (p=0.256) at week 0 and at 12 weeks, creating a standard of normality. Meanwhile, electromyography of the EDLM, innervated by the fibular nerve, showed significant differences between the amplitudes (p=0.003) and latencies (p=0.021) at the two different moments of observation.CONCLUSION:Intraoperative electromyography determined and quantified gastrocnemius muscle motor unit integrity, innervated by tibial nerve. Although this study was not useful to, objectively, assess extensor digitorum longus muscle motor unit, innervated by fibular nerve.(AU)

A histomorphometric study of unmyelinated fibers of the fibular nerve in Wistar rats / Histomorfometria das fibras amielínicas do nervo fibular em ratos Wistar

ABSTRACT There are few histomorphometric studies on the unmyelinated fibers of the fibular nerve in rats, and the number of experimental studies using this nerve has been increasing in the last years. Sixty-two percent of the endoneurial area from 10 fibular nerves of adult Wistar rats was scanned by electron microscopy, and digitized. The total number of unmyelinated axons (1.882 ± 271) was significantly lesser, and their axon diameters (0.2 µm to 2.8 µm) significantly higher than that determined in previous studies. The histogram peaked at 1 µm. The differences could be due to the nerve sampled area, the number and the age of the animals evaluated, and the laboratory techniques used. This study brings new and referential data to be used in experimental investigations involving histomorphometric evaluation of the rat fibular nerve.

RESUMO Embora o nervo fibular de ratos venha sendo incluído progressivamente em maior número de estudos experimentais nos últimos anos, há poucos estudos a respeito das suas fibras amielínicas. Os nervos fibulares de 10 ratos Wistar adultos foram avaliados através de microscopia óptica e eletrônica. Varredura sistemática através de microscopia eletrônica de transmissão das áreas fasciculares da porção distal no nervo foi realizada. Em média, 62% da área endoneural foi digitalizada. O número total de axônios amielínicos encontrados (1.882 ± 271) foi significativamente menor e as medidas dos diâmetros axonais (0,2 µm a 2,8 µm) maiores do que o determinado em estudos prévios. O pico do histograma foi constituído por fibras de 1µm. As diferenças podem ser devidas à amostragem de maior área endoneural, ao número e à idade dos animais avaliados, e as técnicas laboratoriais utilizadas. Os dados obtidos podem ser considerados referenciais para o nervo fibular de ratos Wistar adultos.

Transferencia tendinosa de tibial posterior en parálisis del nervio peróneo común: ¿El fin del pie caído? / Tendinous transfer of posterior tibial in paralysis of the common peroneal nerve: The end of the fallen foot?

INTRODUCCIÓN: la lesión del nervio peróneo común es la más frecuente del miembro inferior, resultando en pie caído y marcha en steppage. La reconstrucción nerviosa tiene un resultado desfavorable en la mayoría de las series. Una alternativa terapéutica a dicha reconstrucción es la transferencia del tendón del músculo tibial posterior, cuyo objetivo es lograr la dorsiflexión activa del pie. El objetivo de este trabajo es analizar los resultados obtenidos con esta cirugía. MATERIAL Y MÉTODOS: se analizaron una serie de pacientes a los que se realizó una transferencia de tendón de tibial posterior por pie caído, entre los meses de enero 2008 y junio 2012. Sólo se incluyeron en el análisis aquellos que presentaban un seguimiento de al menos 12 meses. La técnica empleada en todos los procedimientos fue la vía subcutánea, circunferencial, con fijación tendón-tendón, y usando como blanco los tendones del tibial anterior, extensor propio del hallux, extensor común de los dedos y peróneos laterales. La escala de Stanmore fue empleada para analizar los resultados. RESULTADOS: en el período analizado, fueron realizadas 22 transferencias de tibial posterior, de los cuales 19 poseían un seguimiento adecuado. Diez de esos 19 pacientes mostraron un resultado excelente (52,3%), cinco bueno (26,7%), dos pacientes regular (10,5%) y dos malo (10,5 %), de acuerdo a la escala mencionada. Sólo una complicación se verificó en un caso, la pérdida de tensión de la sutura tendinosa, que requirió una nueva cirugía. CONCLUSIÓN: la transferencia tendinosa de tibial posterior es un procedimiento con una alta tasa de éxito, tanto es nuestra serie como en otras publicadas en la literatura. Atento a los resultados generalmente pobres que posee la reconstrucción nerviosa primaria directa, consideramos que en casos seleccionados la técnica de transferencia tendinosa es la primera elección en el pie caído

INTRODUCTION: common peroneal nerve injury is the most frequent nerve deficit affecting the lower limbs, resulting in foot drop and stepagge. Primary surgical nerve repair has an unfavorable outcome in most series. An alternative is posterior tibial tendon transfer, a procedure designed to achieve active dorsiflexion. The aim of this paper is to analyze the results obtained with this surgery. METHODS: between January 2008 and June 2012, all patients submitted for posterior tibial tendon transfer with a minimum follow-up of 12 months, were analyzed. Subcutaneous route was used for the transfer, and tendon-to-tendon suture was employed, using as targets the anterior tibial, extensor hallucis longus, extensor digitorum longus and peroneal tendons. Stanmore scale was used for analysis. RESULTS: a total of 22 patients were operated in the studied period, but 19 who had a minimum follow-up were included in these analysis. The results were excellent in 10 patients (52,3%), good in 5 (26,7%), fair in in 2 patients (10,5%) and poor in 2 (10,5%), according to Stanmore scale. CONCLUSIONS: this tendon transfer has a high rate of success, both in our series and in the literature. Considering the poor results that primary nerve repairs has, we believe that posterior tibial tendon transfer is the first choice for the treatment of foot drop in selected cases

The effective injection zone at the popliteal crease for tibial and common peroneal nerve blocks and its relation with the origin point of the medial and lateral sural cutaneous nerves / Zona de inyección eficaz en el pliegue poplíteo para el bloqueo de los nervios tibial y fibular común y su relación con el punto de origen de los nervios cutáneo sural medial y lateral

A popliteal nerve block may be used to provide anesthesia and extended analgesia of the lower extremity, to ameliorate severe and long lasting postoperative pain. The aim of this study was to elucidate the anatomical location of tibial (TN) and common peroneal (CPN) nerves in the popliteal crease for effective nerve block. Fifty fresh specimens from 27 adult Chinese cadavers (16 males and 11 females, age range from 35 to 87 years) were investigated. Twenty-two cadavers were used to identify nerve locations and 5 cadavers were used to determine the depths of nerves in cross section. TN was found to be located at 50% from the most lateral point of the popliteal crease at 1.4 cm deep to the surface. In 20% of the 50 specimens, the medial sural cutaneous nerve branched out below or at the popliteal crease, whereas the CPN was located at 26.0% from the most lateral point of the popliteal crease and at 0.7 cm deep to the surface. Furthermore, in 6.0% of specimens the lateral sural cutaneous nerve branched out below or at the popliteal crease. This study suggests that the TN and CPN leave the sciatic nerve at variable distances from the popliteal crease. However, we believe that the results of the present study about the location of TN and CPN at the popliteal crease offer a good guide to optimal nerve block.

El bloqueo nervioso poplíteo puede ser utilizado para proporcionar anestesia y analgesia prolongada del miembro inferior y para aliviar el dolor postoperatorio severo y duradero. El objetivo fue determinar la localización anatómica de los nervios tibial (NT) y fibular común (NFC) en el pliegue poplíteo para un bloqueo nervioso efectivo. Se utilizaron 50 miembros inferiores frescos pertenecientes a 27 cadáveres adultos chinos (16 hombres y 11 mujeres, rango de edad entre 35-87 años). Se utilizaron 22 cadáveres para identificar la localización de los nervios y los 5 restantes para determinar la profundidad de los nervios en una sección transversal. El NT se encontró en el 50% de los casos desde el punto más lateral del pliegue poplíteo a 1,4 cm de la superficie. En el 20% de 50 muestras, el nervio cutáneo sural medial se ramificó por debajo o en el pliegue poplíteo, mientras que el NFC se encontró en el 26% de los casos desde el punto más lateral del pliegue poplíteo a 0,7 cm de la superficie. Además, en el 6% de las muestras, el nervio cutáneo sural lateral se ramificó por debajo o en el pliegue poplíteo. Nuestros resultados sugieren que el NT y NFC emergen del nervio ciático a distancias variables del pliegue poplíteo. Creemos que los resultados sobre la ubicación de NT y NFC en el pliegue poplíteo ofrecen una buena guía para el adecuado bloqueo nervioso.

Peroneal nerve reconstruction by using glycerol-preserved veins: histological and functional assessment in rats

PURPOSE: To compare the degree of neural regeneration in rats upon interposition of autologous nerve graft, autogenous vein, glycerol-preserved autogenous vein, and glycerol-preserved allogeneic vein using qualitative and quantitative histological analyses as well as functional assessments. METHODS: Peroneal nerves were reconstructed differently in four groups of animals. Functional assessments were performed pre- and postoperatively for a period of six weeks. After six weeks, the animals were sacrificed and histological evaluations were performed. RESULTS: Histological patterns of autogenous veins without preservation showed pronounced neoangiogenesis and extensive axonal rarefaction, as confirmed by axonal counting and functional assessments. Glycerol-preserved veins had results similar to the control. CONCLUSIONS: Glycerol-preserved autogenous or allogeneic veins showed similar results to autograft results. The autogenous vein (without preservation in glycerol) presented histological and functional outcomes statistically lower than other groups.

Effect of electrical stimulation of the cranial tibial muscle after end-to-side neurorrhaphy of the peroneal nerve in rats

PURPOSE: To investigate the efficiency of electrical stimulation in the muscle maintenance and nerve regeneration after end-to-side neurorrhaphy (ESN). METHODS: Sixty male Wistar rats (Rattus norvegicus) were divided into four experimental groups. Control group (Control), Denervated Group (Denervated); Group with End-to-side neurorrhaphy (ESN); Group with End-to-side neurorrhaphy and electrical stimulation (ESN + ES). We perform electrical stimulation in rats after they had undergone muscle reinnervation by ESN. We collected morphometric and functional data. RESULTS: When comparing the mass of the treated side of cranial tibial muscle (CTM) and that of normal side of CTM, the group ESN + ES (26.12%) exhibited lower mass loss than that of group ESN (37.23%). The peroneal functional index showed that group ESN + ES equaled that of the Control group and showed an evolution of 60.5% while group ESN showed an evolution of 9.5%. In measuring maximum strength of CTM, the group ES + ESN outperformed group ESN. The muscle and nerve morphometry showed superiority of group ES+ESN over ESN group in all parameters. CONCLUSION: Electrical stimulation is an effective means of maintaining functional muscle and nerve regeneration after end-to-side neurorrhaphy.