Anterior Tarsal Tunnel Syndrome: Entrapment of the Articular Branch of Deep Peroneal Nerve: A Case Report.

CASE: A 28-year-old male patient who injured his ankle 2 years ago presented with unilateral ankle pain, tingling, and numbness for 1 year. Clinically, tenderness and positive Tinel sign were localized on anterior aspect of ankle. On exploration, deep peroneal nerve and mainly its articular branch were encased in fibrotic tissue. Decompression of both nerves resulted in symptomatic relief after surgery. CONCLUSION: High index of suspicion, a thorough medical history, meticulous clinical examination, complete knowledge of nerve anatomy, proper radiological studies, and careful surgical decompression are all necessary for the diagnosis and management of such atypical cases.

Pediatric Peroneal Nerve Palsy Secondary to Fibular Osteochondroma.

Peripheral nerve injuries due to mass effect from bony lesions can occur when the nerve exists in an anatomically constrained location, such as the common peroneal nerve at the fibular head which passes into the tight fascia of the lateral leg compartment. We report a case of a pediatric patient who developed a common peroneal nerve palsy secondary to an osteochondroma of the fibular head and describe the clinical evaluation, radiographic findings, and surgical approach. Rapid diagnosis and nerve decompression after the onset of symptoms restored full motor function at the 8-month postoperative mark.

Preoperative Imaging of Intraneural Ganglion Cysts: A Critical Systematic Analysis of the World Literature.

BACKGROUND: Advancements in imaging and an understanding of the pathomechanism for intraneural ganglion cyst formation have led to increased awareness and recognition of this lesion. However, the precise role of imaging has been advocated for but not formally evaluated. METHODS: We performed a systematic review of the world literature to study the frequency of imaging used to diagnose intraneural ganglion cysts at different sites and compared trends in identifying joint connections. RESULTS: We identified 941 cases of intraneural ganglion cysts, of which 673 had published imaging. Magnetic resonance imaging (MRI, n = 527) and ultrasonography (US, n = 123) were the most commonly reported. They occurred most frequently in the common peroneal nerve (n = 570), followed by the ulnar nerve at the elbow (n = 88), and the tibial nerve at the ankle (n = 58). A joint connection was identified in 375 cases (48%), with 62% of MRIs showing a joint connection, followed by 16% on US, and 6% on computed tomography (CT). MRI was statistically more likely to identify a joint connection than was US (P < 0.01). In the last decade, joint connections have been identified with increasing frequency using preoperative imaging, with up to 75% of cases reporting joint connections. CONCLUSIONS: Preoperative imaging plays an important role in establishing the diagnosis of intraneural ganglion cyst as well as treatment planning. Imaging has proved superior to the sole reliance of operative exposure to identify a joint connection, which is necessary to treat the underlying disease. Failure to identify cyst connections on imaging can result in an inability to truly address the underlying pathoanatomy at the time of definitive surgery, leading to a risk for clinical recurrence. Therefore, management should be guided by an intersection between new knowledge presented in the literature, clinical expertise, and surgeon experience.

The Risk of Iatrogenic Peroneal Nerve Injury in Lateral Meniscal Repair and Safe Zone to Minimize the Risk Based on Actual Arthroscopic Position: An MRI Study.

BACKGROUND: Lateral meniscal repair using an all-inside meniscal repair device involves a risk of iatrogenic peroneal nerve injury. To our knowledge, there have been no previous studies evaluating the risk of injury with the knee in the standard operational figure-of-4 position with joint dilatation in arthroscopic lateral meniscal repair. PURPOSE: To evaluate and compare the risk of peroneal nerve injury and establish the safe and danger zones in repairing the lateral meniscus through the anteromedial, anterolateral, or transpatellar portal in relation to the medial and lateral borders of the popliteal tendon (PT). STUDY DESIGN: Descriptive laboratory study. METHODS: Using axial magnetic resonance imaging (MRI) studies of knees in the figure-of-4 position with joint fluid dilatation at the level of the lateral meniscus, we drew direct lines to simulate a straight all-inside meniscal repair device deployed from the anteromedial, anterolateral, and transpatellar portals to the medial and lateral borders of the PT. If the line passed through or touched the peroneal nerve, a risk of iatrogenic peroneal nerve injury was noted, and measurements were made to determine the safe and danger zones for peroneal nerve injury in relation to the medial or lateral border of the PT. RESULTS: Axial MRI images of 29 adult patients were reviewed. Repairing the lateral meniscus through the anteromedial portal in relation to the lateral border of the PT and through the anterolateral portal in relation to the medial border of the PT had a 0% risk of peroneal nerve injury. The "safe zone" in relation to the medial border of the PT through the anterolateral portal was between the medial border of the PT and 9.62 ± 4.60 mm medially from the same border. CONCLUSION: It is safe to repair the body of the lateral meniscus through the anteromedial portal in the area lateral to the lateral border of the PT or through the anterolateral portal in the area medial to the medial border of the PT. CLINICAL RELEVANCE: There is a risk of iatrogenic peroneal nerve injury during lateral meniscal repair. Thus, we recommend repairing the lateral meniscal tissue through the anteromedial portal in the area lateral to the lateral border of the PT and using the anterolateral portal in the area medial to the medial border of the PT, as neither of these approaches resulted in peroneal nerve injury. Additionally, the surgeon can decrease this risk by repairing the meniscal tissue using the all-inside meniscal device in the safe zone area.

Matched-Pair Analysis of Magnetic Resonance Images for Location of the Common Peroneal Nerve in Valgus Knees: Comparison with the Varus Knees.

This study aimed to assess the distance and angular location of the common peroneal nerve (CPN) on axial magnetic resonance imaging (MRI) in the valgus knees and compare the measurements with those obtained from the control group. We compared the location of the CPN according to the type of alignment by performing a subgroup analysis. From January 2009 to December 2019, we identified 41 knees with preoperative MRI in patients who underwent total knee arthroplasty (TKA) for valgus deformity (valgus group). We performed one-to-two matched-pair analysis to a cohort of patients who underwent MRI but were not candidates for TKA (control group), according to sex and age. The valgus group was classified according to the grading system reported by Ranawat et al, and the control group was also subdivided according to the hip-knee-ankle (HKA) angle obtained from lower extremity scanography: neutral (-3 to +3 degrees from the neutral mechanical axis), valgus (> +3 degrees), and varus alignment (< -3 degrees). Distance between the CPN and posterolateral cortex of the tibia at the knee joint (distance J) and tibial cut level (distance C) were measured. Angle of the CPN from the central anteroposterior axis of the tibia (angle α) was measured. We compared the measurements between the groups. Distance J was significantly closer in the valgus group (p < 0.001), whereas angle α was significantly smaller in the valgus group (p < 0.001). However, no significant differences were found in the subgroup analysis. Moreover, a significant correlation was found between distance J and the HKA angle (p < 0.001). The location of the CPN in the valgus knees was closer to the posterolateral cortex of the tibia at the joint level and showed a smaller angle than that in the other aligned knees. We recommend that lateral soft tissue release for valgus knees should not be performed at the joint line. The results of this study suggest that this would be less safe than a release performed at the level of the proximal tibial bone resection.

Large Schwannoma of the Deep Peroneal Nerve: A Case Report.

This article presents the case of a 32-year-old female patient with schwannoma. The patient had swelling on the anterior aspect of her right foot for 1 year with increasing pain over the past 2 months. Moreover, a positive Tinel sign was present over the swelling. Magnetic resonance imaging revealed a large schwannoma mass in the deep peroneal nerve. Consequently, the patient?s large schwannoma was completely excised along with its capsule. Schwannomas are benign tumors of the peripheral nerves that rarely exhibit malignant transformation. Treatment is considered to be curative if complete resection is achieved.

Neurolymphomatosis related to direct epineural invasion of the superficial peroneal nerve from subcutaneous B-cell lymphoma.

Neurolymphomatosis is a rare complication of systemic lymphomas, and is classically related to hematogenous spread or intraneural spread of tumor cells from the leptomeninges. Here we report a case of neurolymphomatosis related to direct epineural invasion of the superficial peroneal nerve from subcutaneous localization of B-cell lymphoma. Nerve biopsy revealed striking histological features suggestive of contiguous infiltration of the superficial peroneal nerve by subcutaneous lymphoma. We think this case report sheds new light on neurolymphomatosis pathophysiology with an unreported mechanism in B-cell lymphoma. It also points out that the clinical spectrum in neurolymphomatosis is really variable, pure sensory mononeuritis being a rare presentation. Finally, our case is also strongly illustrative of the contribution of early nerve ultrasonography in the patient diagnosis and in guidance of the nerve biopsy.

Intraneural ganglion cyst of the common peroneal nerve causing foot drop in a 12-year old child.

OBJECTIVES: Intraneural ganglia are benign fluid-filled cysts contained within the subepineurial space of peripheral nerves. The common peroneal nerve at the fibular neck is by far the most frequently involved, although other nerves can be affected as well. Although the differential diagnosis of foot drop in adults and children show some differences, clinical presentation, diagnostic workup, treatment and follow-up of intraneural ganglia are quite similar in both groups. The primary objective was to create an overview of intraneural ganglia in children, with an emphasis on diagnostic workup and potential pitfalls during neurosurgical intervention, based on all available literature concerning this topic and own center experiences. As a secondary objective, we tried to raise the awareness concerning this unique cause of foot drop in childhood. PATIENTS AND METHODS: We performed a review of the literature, in which children who developed foot drop secondary to an intraneural ganglion cyst of the common peroneal nerve were examined. A total of eleven articles obtained from MEDLINE were included. Search terms included: "pediatric", "children", "child", "intraneural ganglia", "intraneural ganglion cysts", "foot drop", "peroneal nerve" and "fibular nerve". Additional studies were identified by checking reference lists. Furthermore, we present the case of a 12-year old girl with foot drop caused by an intraneural ganglion cyst. She underwent cyst decompression with evacuation of intraneural cyst fluid and articular branch disconnection. PRISMA and CARE statement guidelines were followed. RESULTS: We hypothesize that minor injury caused a breach in the joint capsule, resulting in synovial fluid egression along the articular nerve branch, corroborating the unifying articular theory and emphasizing the need for ligation of said branch. Foot drop is a predominant characteristic, explained by the proximity of the anterior tibial muscle motor branch near the articular branch nerve. In children, satisfactory motor recovery after surgical decompression is to be expected. CONCLUSION: Sudden or progressive foot drop in children warrants an exhaustive neurophysiological and radiological workup. The management of intraneural ganglia is specific, consisting of nerve decompression, articular branch ligation and joint disarticulation, if deemed necessary. Our surgical results support the unifying articular theory and emphasize the importance of ligation and transection of the articular branch nerve, distally from the anterior tibial muscle branch, in order to prevent intraneural ganglia recurrence. This well-documented case adds depth to the current literature on this sparsely reported entity.

Determining the real site of peroneal nerve injury with knee dislocation: Earlierier is easier.

Common peroneal nerve (CPN) injury is a recognised complication of traumatic knee dislocation with a direct association between the degree of ligamentous injury and the degree of CPN injury. It is essential explore and repair these injuries in good time to reduce morbidity. Often exploration only involves the portion of this nerve associated with the joint as it courses around the fibular head. However, a recent case highlighted the importance of proximal exploration to its branching point from the sciatic nerve, a known point of fragility, even if other defects have been identified.

Intravenous contrast does not improve detection of nerve lesions or active muscle denervation changes in MR neurography of the common peroneal nerve.

OBJECTIVE: To evaluate the effect of intravenous (IV) contrast on sensitivity, specificity, and accuracy of magnetic resonance (MR) neurography of the knee with attention to the common peroneal nerve (CPN) in identifying nerve lesions and active muscle denervation changes. MATERIALS AND METHODS: A retrospective search for contrast-enhanced MR neurography cases evaluating the CPN at the knee was performed. Patients with electrodiagnostic testing (EDX) within 3 months of imaging were included and those with relevant prior surgery were excluded. Two radiologists independently reviewed non-contrast sequences and then 4 weeks later evaluated non-contrast and contrast sequences. McNemar's tests were performed to detect a difference between non-contrast only and combined non-contrast and contrast sequences in identifying nerve lesions and active muscle denervation changes using EDX as the reference standard. RESULTS: Forty-four exams in 42 patients (2 bilateral) were included. Twenty-eight cases had common peroneal neuropathy and 29, 21, and 9 cases had active denervation changes in the anterior, lateral, and posterior compartment/proximal muscles respectively on EDX. Sensitivity, specificity, and accuracy of non-contrast versus combined non-contrast and contrast sequences for common peroneal neuropathy were 50.0%, 56.2%, and 52.3% versus 50.0%, 56.2%, and 52.3% for reader 1 and 57.1%, 50.0%, and 54.5% versus 64.3%, 56.2%, and 61.4% for reader 2. Sensitivity, specificity, and accuracy of non-contrast and combined non-contrast and contrast sequences in identifying active denervation changes for anterior, lateral, and posterior compartment muscles were not significantly different. McNemar's tests were all negative. CONCLUSION: IV contrast does not improve the ability of MR neurography to detect CPN lesions or active muscle denervation changes.

The articular branch of the peroneal nerve to the proximal tibiofibular joint descends at a mean height of approximately 18 mm distal to the postero-lateral tip of the fibular head.

PURPOSE: The aim of the study was to evaluate the anatomical details of the articular branch of the peroneal nerve to the proximal tibiofibular joint and to project the height of its descent in relation to the fibular length. METHODS: Twenty-five lower extremities were included in the study. Following identification of the common peroneal nerve, its course was traced to its division into the deep and superficial peroneal nerve. The articular branch was identified. The postero-lateral tip of the fibular head was marked and the interval from this landmark to the diversion of the articular branch was measured. The length of the fibula, as the interval between the postero-lateral tip of the fibular head and the tip of the lateral malleolus, was evaluated. The quotient of descending point of the articular branch in relation to the individual fibular length was calculated. RESULTS: The articular branch descended either from the common peroneal nerve or the deep peroneal nerve. The descending point was located at a mean height of 18.1 mm distal to the postero-lateral tip of the fibular head. Concerning the relation to the fibular length, this was at a mean of 5.1%, starting from the same reference point. CONCLUSION: The articular branch of the common peroneal nerve was located at a mean height of 18.1 mm distal to the the postero-lateral tip of the fibular head, respectively, at a mean of 5.1% of the whole fibular length starting from the same reference point. These details represent a convenient orientation during surgical treatment of intraneural ganglia of the common peroneal nerve, which may result directly from knee trauma and indirectly from ankle sprain.

Arthroscopic treatment of lateral ankle instability. Is there a safe zone? An anatomic study.

BACKGROUND: The purpose of this study is to describe the relative location of superficial anatomic landmarks and likely location of structures at risk in order to predict the proximity of the later and avoid their injury during the arthroscopic treatment of lateral ankle instability. METHODS: Fifteen cadaver ankles were dissected. Based on superficial anatomic landmarks, the location and distances to the structures at risk (extensor tendons, peroneus tertius, peroneal tendons, main branch or intermediate branch of the superficial peroneal nerve, and the sural nerve) were measured. RESULTS: The distance from the lateral malleolus along the peroneus brevis to its intersection by the sural nerve was 38.5±10.5mm and from it to the superficial peroneal nerve was 32.0±7.4mm. Based on the minimum distances, a rectangular area of 25mm×22mm was obtained. The anterior talofibular ligament and the proximal border of the inferior extensor retinaculum were within this area. CONCLUSIONS: Our study suggests that based on superficial anatomic landmarks, it is possible to define an anatomic area in order to avoid structures at risk. In addition to the usual precautions, these anatomical references may contribute to lower the complication rate associated to the arthroscopic treatment of lateral ankle instability.

Concurrent Schwannoma and Intraneural Ganglion Cyst Involving Branches of the Common Peroneal Nerve.

Benign peripheral nerve sheath tumors are well known to neurosurgeons and a relatively commonly seen pathology. Intraneural ganglion cysts, once thought to be rare and poorly understood, are increasingly recognized in clinical practice and better understood based on the advent of high-resolution imaging. There are few reports of different nerve lesions in the same anatomic location appearing concurrently. Herein we present a patient with 2 distinct pathologies explaining 2 distinct symptom complexes-sensory changes in the superficial peroneal distribution (from a schwannoma of the superficial peroneal nerve) and mild motor weakness in the tibialis anterior (from an intraneural ganglion cyst arising from the superior tibiofibular joint affecting this motor branch). Recognition of the 2 pathologies allowed targeted surgical approaches, which led to resolution of the symptoms.

Oblique proximal locking screw in tibial fracture intramedullary nailing: a clinical imaging study of proximity to common peroneal nerve.

Intramedullary nailing (IMN) is the treatment of choice in the surgical management of most tibia shaft fractures. The aim of the study was to evaluate the proximity of the common peroneal nerve (CPN) to the oblique proximal locking screw inserted from the anteromedial to the posterolateral direction. We identified all the patients who underwent the IMN of the tibia between 2008 and 2018. Patients who underwent post-operative computed tomography for any reason were identified. Patients were included if the CPN was visible on the axial slices, the proximal oblique locking screw was used, or the line of the drilling could be reconstructed. Twenty-nine patients met the inclusion criteria. The median length of the intramedullary nail was 345 mm. The median nail diameter was 10 mm. The median number of proximal interlocking screws was 2. All scans were reviewed by the musculoskeletal radiologist for verifying the visibility and marking of the CPN. The mean screw trajectory angle to the CPN was 9° (± 9°). Most of the drilling trajectories passed posterior to the CPN (79%). The depth of the intramedullary nail was on average - 8 mm (± 10 mm). A negative correlation was observed between the depth of the nail and the distance from the CPN (P < 0.001). During the insertion of the oblique proximal locking screw from the anteromedial to the posterolateral direction, the CPN is potentially at risk if the drill is allowed to plunge or an incorrectly long screw is used. Sinking the nail provides a better margin of safety.

To Block or Not to Block: Role of Ultrasonography in Guiding an Anesthetic Plan for a Patient With Charcot-Marie-Tooth Disease.

A 31-year-old man scheduled for a fifth metatarsal head resection secondary to osteomyelitis presented to the preoperative holding area for placement of an ultrasound-guided popliteal nerve block as part of a multimodal pain management plan. During the preoperative evaluation, a medical history of CharcotMarie-Tooth disease was noted. The patient had decreased range of motion and neuropathy in both lower extremities and required an assistive device when ambulating. Before placement of the block, a pre-procedure scan of the popliteal fossa revealed abnormal sonoanatomy of the distal sciatic nerve as well as the proximal tibial and common peroneal nerve branches. The surgeon was consulted regarding the ultrasonography findings, and the proposed block was abandoned. A field block proximal to the surgical site was performed under monitored anesthesia care, with an understanding that the case would convert to general anesthesia using a laryngeal mask airway if the procedure was not tolerated. The surgery was performed as planned without any difficulties, and the patient was transferred to the postanesthesia care unit. The postoperative course was uneventful, and the patient was discharged home.

Ultrasound in the diagnosis and management of fibular mononeuropathy.

INTRODUCTION: Ultrasound (US) evaluation of peripheral nerves is a noninvasive, cost-effective approach to diagnosing focal mononeuropathies and guiding surgical management. We used the intranerve ratio to evaluate for possible cut-off values in diagnosis of fibular mononeuropathies (FNs). METHODS: A retrospective analysis of FN confirmed by electrodiagnosis (EDx) was performed to identify intranerve ratio values between affected and unaffected limbs at the fibular head and popliteal fossa. RESULTS: The optimal fibular head/popliteal fossa intranerve ratio to discriminate between limbs with and without disease was 1.25 (sensitivity, 51%; specificity, 71%). There was no statistically significant difference between affected vs unaffected limbs (ratio, 1.13; P = .15) nor in subgroup analyses. However, 25% of patients had structural lesions amenable to surgery. DISCUSSION: The utility of US in diagnosis of FN is limited using intranerve ratio data, but US has a distinct advantage over EDx for identifying treatable structural lesions.

Thread common peroneal nerve release-a cadaveric validation study.

OBJECTIVE: To determine if the thread release technique can be applied to common peroneal nerve entrapment at the fibular neck. METHODS: The thread common peroneal nerve release was performed on 15 fresh frozen cadaveric lower extremity specimens. All procedures were performed under ultrasound guidance and immediately underwent post-procedural gross anatomic inspection for completeness of decompression and presence or absence of iatrogenic neurovascular injury. RESULTS: All 15 specimens demonstrated complete transection of the deep fascia of the peroneus longus overlying the common peroneal nerve. The transections extended to the bifurcation of the superficial peroneal and deep peroneal nerves. There was no evidence of any iatrogenic damage to the neurovascular bundle or adjacent tendons. The average operating time was less than 30 min. CONCLUSION: This cadaveric validation study demonstrates the accuracy of the thread common peroneal nerve release. Future pilot studies are warranted to ensure the safety of this procedure in the clinical setting.