Fibular Nerve Repair by Lateral Sural Cutaneous Nerve Graft: Anatomic Feasibility Study and Clinical Results.

OBJECTIVE: The common fibular nerve (CFN) is the most frequently injured nerve in the lower limbs. Surgical management is necessary in approximately two thirds of patients and includes neurolysis, suture, graft repair, or nerve transfer. The distal sural nerve is the preferred donor for grafting, but it is not without complications and requires a second incision. We sought to study the surgical anatomy of the lateral sural cutaneous nerve (LSCN) with the aim of repairing CFN injuries through the same incision and as a potential source for grafting in other nerve injuries. METHODS: The popliteal fossa was dissected in 11 lower limbs of embalmed cadavers to study LSCN variations. Four patients with CFN injuries then underwent surgical repair by LSCN grafting using the same surgical approach. RESULTS: At the medial margin of the biceps femoris, the LSCN emerged from the CFN approximately 8.15 cm above the fibular head. The LSCN ran longitudinally to the long axis of the popliteal fossa, with an average of 3.2 cm medial to the fibular head. The mean LSCN length and diameter were 9.61 cm and 3.6 mm, respectively. The LSCN could be harvested in all patients for grafting. The mean graft length was 4.4 cm. Motor function was consistently recovered for foot eversion but was recovered to a lesser extent for dorsiflexion and toe extension. All patients recovered sensitive function (75% of S3). Hypoesthesia was recognized at the calf. CONCLUSIONS: LSCN harvest is a viable alternative for nerve grafting, especially for repairing short CFN injuries, thereby avoiding the need for a second incision.

Estudio biométrico de la distribución de los ramos motores del nervio fibular superficial en el compartimiento lateral de la pierna en individuos brasileiros: implicancias clínicas y variaciones / Biometric study of the distribution of the motor branches of the superficial fibular nerve in the lateral compartment of the leg in Brazilian individuals: clinical implications and variations

El propósito del presente estudio fue conocer la distribución de los ramos motores del nervio fibular superficial (NFS) y de sus respectivas penetraciones en los músculos fibulares en relación al ápice de la cabeza de la fíbula, dividiendo el compartimiento lateral de la pierna en tres regiones a fin de hacer posible una visión más segura de sus correlaciones clínicas y quirúrgicas. A través de disección, se estudiaron 60 piernas pareadas de 30 cadáveres adultos, de ambos sexos, Brasileños, con edad promedio de 44,9 años, siendo 8 de sexo femenino y 22 del masculino. Después de la disección se registraron las distancias de los puntos de penetración de los ramos del NFS en los músculos fibular largo (mFL) y corto (mFC), localizándolos en los tercios proximal, medio o distal, según fuere el caso. Se observó que el mayor número de ramos penetraron en el mFL a nivel de la parte distal del tercio proximal de la pierna, mientras que en el mFC lo hicieron en las partes proximal y distal del tercio medio de la pierna. Los ramos motores para el mFL penetraban en el vientre muscular entre 48,06 y 141,56 mm, y los ramos para el mFC lo hicieron entre 163,34 y 209,67 mm del origen del nervio. No hubo diferencias estadísticamente significativas ni entre los lados derecho e izquierdo ni entre genéros. Independiente de las diferencias metodológicas entre los estudios disponibles, el detalle de la distribución nerviosa en este compartimiento, permitirá una mayor precisión en el momento de elegirse un área para colgajo de injerto autólogo y una menor chance de lesiones iatrogénicas durante cirugías de la región.

The purpose of the present study was to know the distribution of the motor branches of the superficial fibular nerve (SFN) and their respective motor points in the fibular muscles in relation to the apex of the head of the fibula, dividing the lateral compartment of the leg in three regions in order to make possible a safer view of your clinical and surgical correlations. Through dissection, 60 paired legs of 30 adult cadavers, of both sexes, Brazilians, with an average age of 44.9 years, 8 being female and 22 male, were studied. After the dissection, the distances of the motor points of the NFS branches in the fibularis longus (FLm) and brevis (FBm) muscles were recorded, locating them in the proximal, middle or distal thirds. It was observed that the largest number of branches penetrated the FLm at the level of the distal part of the proximal third of the leg, while in the FBm they did so in the proximal and distal parts of the middle third of the leg. The motor branches for the FLm penetrated into the muscular belly between 48.06 and 141.56 mm, and the branches for the FBm did between 163.34 and 209.67 mm of the origin of the nerve. There were no statistically significant differences between the right and left sides or between genres. Regardless of the methodological differences between the available studies, the detail of the nervous distribution in this compartment will allow a greater precision at the time of choosing an area for autologous graft flap and a lower chance of iatrogenic injuries during surgeries of the region.

Additive manufactured biodegradable poly(glycerol sebacate methacrylate) nerve guidance conduits.

Entubulating devices to repair peripheral nerve injuries are limited in their effectiveness particularly for critical gap injuries. Current clinically used nerve guidance conduits are often simple tubes, far stiffer than that of the native tissue. This study assesses the use of poly(glycerol sebacate methacrylate) (PGSm), a photocurable formulation of the soft biodegradable material, PGS, for peripheral nerve repair. The material was synthesized, the degradation rate and mechanical properties of material were assessed and nerve guidance conduits were structured via stereolithography. In vitro cell studies confirmed PGSm as a supporting substrate for both neuronal and glial cell growth. Ex vivo studies highlight the ability of the cells from a dissociated dorsal root ganglion to grow out and align along the internal topographical grooves of printed nerve guide conduits. In vivo results in a mouse common fibular nerve injury model show regeneration of axons through the PGSm conduit into the distal stump after 21 days. After conduit repair levels of spinal cord glial activation (an indicator for neuropathic pain development) were equivalent to those seen following graft repair. In conclusion, results indicate that PGSm can be structured via additive manufacturing into functional NGCs. This study opens the route of personalized conduit manufacture for nerve injury repair. STATEMENT OF SIGNIFICANCE: This study describes the use of photocurable of Poly(Glycerol Sebacate) (PGS) for light-based additive manufacturing of Nerve Guidance Conduits (NGCs). PGS is a promising flexible biomaterial for soft tissue engineering, and in particular for nerve repair. Its mechanical properties and degradation rate are within the desirable range for use in neuronal applications. The nerve regeneration supported by the PGS NGCs is similar to an autologous nerve transplant, the current gold standard. A second assessment of regeneration is the activation of glial cells within the spinal cord of the tested animals which reveals no significant increase in neuropathic pain by using the NGCs. This study highlights the successful use of a biodegradable additive manufactured NGC for peripheral nerve repair.

Peroneal Nerve Palsy: Evaluation and Management.

Peroneal nerve palsy is the most common entrapment neuropathy of the lower extremity. Numerous etiologies have been identified; however, compression remains the most common cause. Although injury to the nerve may occur anywhere along its course from the sciatic origin to the terminal branches in the foot and ankle, the most common site of compressive pathology is at the level of the fibular head. The most common presentation is acute complete or partial foot drop. Associated numbness in the foot or leg may be present, as well. Neurodiagnostic studies may be helpful for identifying the site of a lesion and determining the appropriate treatment and prognosis. Management varies based on the etiology or site of compression. Many patients benefit from nonsurgical measures, including activity modification, bracing, physical therapy, and medication. Surgical decompression should be considered for refractory cases and those with compressive masses, acute lacerations, or severe conduction changes. Results of surgical decompression are typically favorable. Tendon and nerve transfers can be used in the setting of failed decompression or for patients with a poor prognosis for nerve recovery.

[A FEASIBILITY STUDY ON TRANSPOSITION OF PROXIMAL MOTOR BRANCHES FROM TIBIAL NERVE TO RECONSTRUCT DEEP FIBULAR NERVE].

OBJECTIVE: To explore the feasibility of transposition of the proximal motor branches from tibial nerve (TN) as direct donors to suture the deep peroneal nerve (DPN) so as to provide a basis for surgical treatment of high fibular nerve injury. METHODS: Nineteen lower limb specimens were selected from 3 donors who experienced high-level amputation (2 left limbs and 1 right limb) and 8 fresh frozen cadavers (8 left limbs and 8 right limbs). The length and diameter of the three motor branches from TN (soleus, medial gastrocnemius, and lateral gastrocnemius) and the distance from the initial points to the branch point of the common peroneal nerve (CPN), as well as the length and diameter of the noninvasive separated bundles of DPN, then the feasibility of tensionless suturing between the donor nerves and the DPN bundle was evaluated. At last, part of the nerve tissue was cut out for HE and Acetylcholine esterase staining observation and the nerve fiber count. RESULTS: Gross anatomic observation indicated the average distance from the initial points of the three donor nerves to the branch point of the CPN was (71.44 ± 2.76) (medial gastrocnemius), (75.66 ± 3.20) (lateral gastrocnemius), and (67.50 ± 3.22) mm (soleus), respectively. The three donor nerves and the DPN bundles had a mean length of (31.09 ± 2.01), (38.44 ± 2.38), (59.18 ± 2.72), and (66.44 ± 2.85) mm and a mean diameter of (1.72 ± 0.08), (1.88 ± 0.08), (2.10 ± 0.10), and (2.14 ± 0.12) mm, respectively. The histological observation showed the above-mentioned four nerve bundles respectively had motor fiber number of 2,032 ± 58, 2.186 ± 24, 3,102 ± 85, and 3,512 ± 112. Soleus nerve had similar diameter and number of motor fibers to DPN bundles (P > 0.05), but the diameter and number of motor fibers of the medial and lateral gastrocnemius were significantly less than those of DPN bundles (P < 0.05). CONCLUSION: All of the three motor branches from TN at popliteal fossa can be used as direct donors to suture the DPN for treating high CPN injuries. The nerve to the soleus muscle should be the first choice.

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.

Ultrasound and neurophysiological correlation in common fibular nerve conduction block at fibular head.

OBJECTIVE: Ultrasound (US) and neurophysiological examination are useful tools in the evaluation of common fibular mononeuropathy. There is only a report comparing US and electrophysiological parameters in patients with common fibular nerve (CFN) conduction block at fibular head. We investigated the correlation between US and neurophysiologic findings in this condition. METHODS: We retrospectively reviewed patients with CFN assessed in our lab during last 2 years. Each patient underwent to clinical, neurophysiological and ultrasound evaluations. Cross sectional area (CSA) of CFN at fibular head was assessed. RESULTS: Twenty-four patients were included. Motor nerve conduction study showed a reduction of distal compound muscle action potential (CMAP) amplitude in 10 patients (mean 1.3 mV). US showed an increased CSA in 10 patients. Statistical analysis revealed a strong correlation between the increased CSA and the CMAP reduction of CFN. CONCLUSION: Our data suggest that usually US examination is normal in CFN conduction block at fibular head. However the association with axonal damage is frequently accompanied by an increase of CSA. SIGNIFICANCE: Ultrasound evaluation may represent a powerful diagnostic/prognostic tool in cases with CPN conduction block at fibular head because it usually shows normal pattern in pure conduction block and increase of CSA in associated axonal damage.

[Neurovascular lesion after total hip arthroplasty in congenital hip dysplasia--case report].

INTRODUCTION: Nowadays, the total hip arthroplasty is a very frequent surgical intervention. In some cases, vascular and nerve injuries may happen around the hip with total hip arthroplasty. Although they are very rare, they may be very dangerous for the patient in some cases. This paper presents a case of a female patient, in whom the nervous fibularis lesion was detected after the total hip arthroplasty, and the occlusion of the iliac femoral artery was revealed later during physical therapy. CASE REPORT: We described a case of a 32-year-old female patient, in whom the nervous fibularis lesion was detected after the total hip arthroplasty. The patient was referred to a ward for physical therapy. On the 19th postoperative day, she felt a vigorous ache and numbness on the left operated leg during stimulation of the paretic fibular musculature. Clinically weak inguinal arterial pulse was detected. After the examination, iliac-femoral occlusion was diagnosed. The patient was referred to the vascular surgeon. In the next few months, she was treated conservatively and eventually underwent surgery. The revascularization was achieved with a satisfactory effect. A year after the total hip replacement, the patient continued with rehabilitation and physical treatment, which lasted one and a half month and had an incomplete functional result - the patient walked with a walking stick and had weak fibular musculature ofa severe degree. The vascular status of the leg was good. CONCLUSION: In this case, neurovascular lesions led to an incomplete functional recovery of the patient and compromised the expected treatment outcome. According to the scoring system used to assess the functionality, the result was marked as poor.

An anatomic study of vascularized fibular grafts.

OBJECTIVE: To study the applied anatomy of the vascular and muscular innervations related to vascularized fibular grafts. METHODS: Thirty-four cadaveric lower extremities were dissected for this study. The observations included fibular length, fibular nutrient artery, arcuate arteries, and innervation of fibular muscles. The fibulas were averagely divided into four segments and the locations of relevant vessels and nerves were ascertained. RESULTS: All specimens had 1 fibular nutrient artery and 4-9 arcuate arteries except 1 specimen which had only 1 arcuate artery. The fibular nutrient artery and the first three arcuate arteries were constantly located between the distal half of the 1/4 segment and 2/4 segment of the fibula. The muscular branch of the superficial peroneal nerve passed through the surface of the periosteum in the 2/4 segment of the fibula. CONCLUSIONS: The most proximal osteotomy point locates at the midpoint of the 1/4 segment by which it ensure the maximal potential for preserving the nutrient vessels. The muscular branch of the superficial peroneal nerve is fragile to injury at the 2/4 segment of the fibula.

[Bilateral leg compartment syndrome due to severe myonecrosis caused by inappropriate use of simvastatin]. / Syndrome de compression des loges bilatéral des membres inférieurs et myonécrose sévère due à l'usage inapproprié de la simvastatine.

Bilateral leg compartment syndrome due to myonecrosis caused by inappropriate use of statins is a rare but potentially fatal complication of this lipid lowering medication. We report a case of a 39-year-old woman who presented with suspicious critical lower limb ischemia. Subsequently, bilateral leg compartment syndrome and myonecrosis developed. The primary cause of myonecrosis was due to misuse of simvastatin mistaken by the patient for a weight-reducing drug. Urgent fasciotomies were performed and the patient underwent urgent renal replacement therapy with continuous hemodialysis for acute renal failure due to myoglobinuria. After this complex treatment, the patient was discharged. She almost fully recovered with only a residual paresis of the left fibular nerve. According to literature, this is a unique case of bilateral compartment syndrome and myonecrosis with acute renal failure due to statin overdose leading to acute renal failure and bilateral fasciotomy.

The precise localization of distal motor branches of the tibial nerve in the deep posterior compartment of the leg.

The tibial nerve has been reported to be often iatrogenically injured during fibular graft harvest, high tibial osteotomy and fascial release procedures. Despite this complication, there are limited data available in the literature concerning the surgical anatomy of tibial nerve branches in the deep posterior compartment of the leg. The aim of the present study was to quantitative and localize the motor nerve points for the flexor hallucis longus (FHL), tibialis posterior (TP) and flexor digitorum longus muscles (FDL) in relation to a regional bony landmark. The range for the number of branches of the tibial nerve and the terminal motor points of each muscle were identified and measurements were made with a digital caliper from these points to the apex of the head of fibula. Three particular types in the branching of tibial nerve were determined. In 55.6% of the cases there were separate branches to each of the muscles in the deep posterior compartment of the leg (Type I). In 30.6% of the cases there were two main branches of the tibial nerve that provided motor branches (Type II). Finally, the tibial nerve had one main branch, which gave rise to separate motor branches to each of the muscles in 13.8% (Type III). In 61.1% of the cases the FHL was innervated by proximal and distal branches of the tibial nerve. In 38.9% of the cases, it was innervated only by one proximal branch. In all of our cases, the TP was innervated by both proximal and distal branches and the FDL innervated only distally. This provided a detailed anatomical description of the tibial nerve in the deep posterior compartment of the leg. Knowledge of the variable peripheral course of the tibial nerve, as well as the detailed anatomy of its motor branches may decrease iatrogenic injuries and motor loss of the foot during surgical procedures.

The medial approach to the fibula: a feasible alternative.

PURPOSE: Since the first harvesting of a microsurgical fibula in 1974 by Ueba and in 1975 by Taylor, using the fibula for osseous reconstruction has proven to be a valuable approach. The harvesting technique, which has been refined by subsequent investigators, has become increasingly standardized, today providing a clear, reproducible method. The procedure involves elevating the fibular graft from lateral, choosing the shortest route to reach the fibula. One disadvantage of this approach is that the bone often obstructs visualization of the vascular pedicle, which lies medially, promoting unintentional injury. In addition, this method is associated with some donor site morbidity, prompting further investigations into accessing the fibula. Here we present an alternative approach for harvesting the fibula and highlight the pros and cons of each approach. PATIENTS AND METHODS: Between 1999 and 2006, a total of 38 microsurgical (23 for the mandible, 9 for the extremities, and 6 for the maxilla) fibula grafts were harvested through the medial approach. RESULTS: In all cases, the patency of the posterior tibial, peroneal vessels, and the tibial nerve could be visualized. Two flaps failed (both mandible, for a success rate of 94.7%). No ischemic or wound healing complications of the lower limb were observed. CONCLUSIONS: The medial approach for harvesting the fibula is a feasible alternative to the lateral approach and provides the surgeon with a comparable likelihood of success. If for some reason access from the lateral approach is contraindicated, then the medial route should be considered.

Epineurial compartments and their role in intraneural ganglion cyst propagation: an experimental study.

New patterns of intraneural ganglion cyst formation are emerging that have not previously been explained in current pathoanatomic terms. We believe there are three important elements underlying the appearance of these cysts: (a) an articular branch of the nerve that connects to a nearby synovial joint; (b) ejected synovial fluid following the path of least resistance along tissue planes; and (c) the additional effects of pressure and pressure fluxes. The dynamic nature of cyst formation has become clearly apparent to us in our clinical, operative and pathologic practice, but the precise mechanism underlying the process has not been critically studied. To test our hypothesis that a fibular (peroneal) or tibial intraneural cyst derived from the superior tibiofibular joint could ascend proximally into the sciatic nerve, expand within it and descend into terminal branches of this major nerve, we designed a series of simple, qualitative laboratory experiments in two cadavers (four specimens, six experiments). Injecting dye into the outer or "epifascicular" epineurium of the fibular and the tibial nerves we observed its ascent, cross over and descent patterns in three of three specimens as well as its cross over after an outer epineurial sciatic injection. In contrast, injecting dye into the inner or "interfascicular" epineurium led to its ascent within the tibial nerve and its division within the sciatic nerve in one specimen and lack of cross over in a sciatic nerve injection. Histologic cross-sections of the nerves at varying levels demonstrated a tract of disruption within the outer epineurium of the nerve injected and the nerve(s) into which the dye, after cross over, descended. Those specimens injected in the inner epineurium demonstrated dye within this tract but without disruption of or dye intrusion into the outer epineurium. In no case did the dye pass through the perineurial layers. Coupled with our observations in previous detailed studies, these anatomic findings provide proof of concept that sciatic cross over occurs due to the filling of its common epineurial sheath; furthermore, these findings, support the unifying articular theory, even in cases wherein patterns of intraneural ganglion cyst formation are unusual. Additional work is needed to be done to correlate these anatomic findings with magnetic resonance imaging and surgical pathology.

Anterior innervation of the proximal tibiofibular joint.

Mucoid cysts compressing the common peroneal nerve have been reported. Whether these cysts are schwannoma or are synovial in nature is the subject of controversy in the medical literature. To contribute to this debate, the present study was designed to detail the anterior innervation of the proximal tibiofibular joint. We dissected 10 knees of five fresh cadavers after staining the tibiofibular joint under fluoroscopic guidance. Through a lateral approach near the fibular head, the common peroneal nerve was isolated then dissected distally to determine whether it or its branches ramified over the proximal tibiofibular joint. In all 10 legs, only one collateral branch was observed on the common peroneal nerve proximal to its terminal division. This collateral sent a branch to the proximal tibiofibular joint before penetrating the tibialis anterior muscle. The articular branch coursed in a superior and posterior direction approximately 1 cm to attain the tibiofibular joint. In no specimen did the deep or superficial peroneal nerves send a twig to the tibiofibular joint. This study confirms and clarifies prior descriptions of the innervation of the anterior aspect of the proximal tibiofibular joint. It clarifies the mechanisms of compression of the common peroneal nerve by synovial cysts that originate from the proximal tibiofibular joint and provides anatomical landmarks that should facilitate complete resection of these cysts.

[Fibular nerve compression due to an unusual cause. A case report]. / Kompression des Nervus peroneus communis mit ungewöhnlicher Ursache. Ein Fallbericht.

There are many factors causing a compression of the fibular nerve accompanied by a loss of function. We describe an unknown cause: a chronic low-grade infection after implantation of a knee endoprosthesis. Perforation of the capsule of the knee joint followed by discharge of polyethylene particles originating from the endoprosthesis. A granuloma developed which resulted in a compression of the peroneal nerve with sensomotor disabilities. Preoperatively we were not able to define the dignity of the tumour. Neurolysis was performed followed by excision of the tumour. The infection was treated by long term antibiotics without removal of the endoprosthesis. Histological examination revealed the definitive diagnosis.

[Nerve compression by mucoid pseudocysts: arguments favoring an articular cause in 23 patients]. / Compression nerveuse par pseudo-kyste mucoïde: à propos de 23 cas. Arguments en faveur de l'origine articulaire.

PURPOSE OF THE STUDY: Mucoid pseudocysts are infrequent benign tumors which can develop on all peripheral nerves near joints. The origin of these cysts remains to be determined. We searched for arguments favoring an articular origin which would have an impact on management and risk of recurrence. MATERIALS AND METHODS: Twenty-three patients (21 men and 2 women, mean age 38 years, age range 13-56 years) presented mucoid pseudocysts and were followed for a mean six years. The mucoid pseudocyst was located on the common fibular nerve at the neck of the fibula in 16 patients, on the tibial nerve at the knee in one, on the median nerve in one, on the ulnar nerve in one, and on the suprascapular nerve in two. Pain was local in 18 patients and irradiated to the concerned nerve territory in 20. Motor deficit was the inaugural feature in 17 patients. EMG was performed in all patients, ultrasound exploration in 15, computed tomography in 7 and magnetic resonance imaging in 10. All patients included in this series underwent surgery: pathological diagnosis of mucoid intra-neural pseudocyst was established in all. Systematic search for communication with the neighboring joint was performed in all cases. RESULTS: An articular communication was found in 17 patients. Mean time to recovery of muscle force (scored 5) and/or normal sensitivity was seven months in 17 patients. One patient did not achieve full recovery. Three patients experienced recurrence and required tibiofibular arthrodesis. DISCUSSION: Three theories have been proposed (cystic degeneration of schwannoma, degeneration of nerve sheath connective tIssue, and an articular origin). The articular theory appears to be the most probable. The presence of an articular pedicle in 60% of the patients, the anatomic juxtaposition between the nerves involved and neighboring joints, and occasional migration along the articular nerve as well as the cyst's mucoid content argue in favor of the articular theory. The notion of recurrence after complete minute excision is also in favor of an articular pathogenic mechanism. The diagnosis of mucoid cyst should be retained as a possibility in patients with rapidly progressive signs of nerve compression near a joint. It is important to search for articular communication before and during the surgical excision in order to limit the risk of recurrence.

Restoration of motor function of the deep fibular (peroneal) nerve by direct nerve transfer of branches from the tibial nerve: an anatomical study.

Traction injuries of the common fibular (peroneal) nerve frequently result in significant morbidity due to tibialis anterior muscle paralysis and the associated loss of ankle dorsiflexion. Because current treatment options are often unsuccessful or unsatisfactory, other treatment approaches need to be explored. In this investigation, the anatomical feasibility of an alternative option, consisting of nerve transfer of motor branches from the tibial nerve to the deep fibular nerve, was studied. In ten cadaveric limbs, the branching pattern, length, and diameter of motor branches of the tibial nerve in the proximal leg were characterized; nerve transfer of each of these motor branches was then simulated to the proximal deep fibular nerve. A consistent, reproducible pattern of tibial nerve innervation was seen with minor variability. Branches to the flexor hallucis longus and flexor digitorum longus muscles were determined to be adequate, based on their branch point, branch pattern, and length, for direct nerve transfer in all specimens. Other branches, including those to the tibialis posterior, popliteus, gastrocnemius, and soleus muscles were not consistently adequate for direct nerve transfer for injuries extending to the bifurcation of the common fibular nerve or distal to it. For neuromas of the common fibular nerve that do not extend as far distally, branches to the soleus and lateral head of the gastrocnemius may be adequate for direct transfer if the intramuscular portions of these nerves are dissected. This study confirms the anatomical feasibility of direct nerve transfer using nerves to toe-flexor muscles as a treatment option to restore ankle dorsiflexion in cases of common fibular nerve injury.

The value of inching technique in evaluating the peroneal nerve entrapment at the fibular head.

The peroneal nerve palsy at the fibular head is quite common but often difficult to diagnose both clinically and electrophysiologically. The purpose of this study was to evaluate the usefulness of the inching in mononeuropathy of the peroneal nerve at the fibular head. Recording from extensor digitorum brevis muscle the nerve was stimulated supramaximally at 1 cm intervals starting 2 cm distal and ending 8 cm proximal to the fibular head. Forty-six patients were examined: the inching was modified in 32 patients. In five of these the motor conduction using conventional method was normal, but the inching was normal or borderline in fourteen patients with reduced conduction velocity across the fibular head. Despite some limitations, the inching can be useful in evaluating patients with suspected palsy of the peroneal nerve at the fibular head.