OBJECTIVE: Common peroneal (fibular) neuropathy is the most common mononeuropathy of the lower extremity. Despite this, there are surprisingly few studies on the topic, and a knowledge gap remains in the literature. As one attempts to address this knowledge gap, a core outcome set (COS) is needed to guide the planning phases of future studies to allow synthesis and comparability of these studies. The objective of this study was to develop the COS-common peroneal neuropathy (CoPe) using a modified Delphi approach.
METHODS: A 5-stage approach was used to develop the COS-CoPe: 1) stage 1, consortium development; 2) stage 2, a literature review to identify potential outcome measures; 3) stage 3, a Delphi survey to develop consensus on outcomes for inclusion; 4) stage 4, a Delphi survey to develop definitions; and 5) stage 5, a consensus meeting to finalize COS and definitions. The study followed the COS-STAndards for Development (COS-STAD) recommendations.
RESULTS: The Core Outcomes in Nerve Surgery (COINS) Consortium comprised 23 participants, all neurological surgeons, representing 13 countries. The final COS-CoPe consisted of 31 data points/outcomes covering domains of demographics, diagnostics, patient-reported outcomes, motor/sensory outcomes, and complications. Appropriate instruments, methods of testing, and definitions were set. The consensus minimum duration of follow-up was 12 months. The consensus optimal time points for assessment were preoperatively and 3, 6, 12, and 24 months postoperatively.
CONCLUSIONS: The COINS Consortium developed a consensus COS and provided definitions, methods of implementation, and time points for assessment. The COS-CoPe should serve as a minimum set of data that should be collected in all future neurosurgical studies on common peroneal neuropathy. Incorporation of this COS should help improve consistency in reporting, data synthesis, and comparability, and should minimize outcome reporting bias.

OBJECTIVE: To explore the clinical utility of ultrasound in evaluating and grading neuromuscular diseases in the lower extremities of patients with diabetes mellitus.
METHODS: A total of 126 inpatients from the Department of Diabetes at Zhangzhou Affiliated Hospital of Fujian Medical University, China, were recruited from June 2020 to December 2022. The cohort included 69 patients with type 2 diabetes mellitus (T2DM) and diabetic peripheral neuropathy (DPN group) and 57 patients with T2DM but without DPN (non-DPN group). Additionally, 80 healthy controls were included. High-frequency ultrasound was used to scan the common peroneal, sural, and tibial nerves, measuring their transverse (D1) and anteroposterior (D2) diameters, and calculating the cross-sectional area (CSA). Changes in the internal echo of the extensor digitorum brevis (EDB) muscle, including maximum thickness and CSA, were also recorded. The DPN group was further subdivided based on disease duration to assess ultrasonic changes over time and the statistical significance of these variations.
RESULTS: Ultrasonic changes such as uneven internal echo reduction, ill-defined epineurial boundaries, and obscured cribriform structures were most prevalent in the DPN group. Significant differences in ultrasound parameters (D1, D2, CSA) were observed among the groups (all P<0.05), with the most pronounced changes in the DPN group. In patients with a disease duration of over 15 years, a significant increase in CSA of lower extremity nerves and a decrease in CSA of the EDB were noted compared to those in the 5-10 years subgroup (19.89±0.98 vs 19.00±0.94; 5.25±0.74 vs 5.93±0.94; all P<0.05).
CONCLUSIONS: High-frequency ultrasound provides a valuable imaging basis for diagnosing and monitoring DPN, demonstrating significant changes in nerve and muscle parameters among diabetic patients.

A ganglion cyst is a benign mass consisting of high-viscosity mucinous fluid. It can originate from the sheath of a tendon, peripheral nerve, or joint capsule. Compressive neuropathy caused by a ganglion cyst is rarely reported, with the majority of documented cases involving peroneal nerve palsy. To date, cases demonstrating both peroneal and tibial nerve palsies resulting from a ganglion cyst forming on a branch of the sciatic nerve have not been reported. In this paper, we present the case of a 74-year-old man visiting an outpatient clinic complaining of left-sided foot drop and sensory loss in the lower extremity, a lack of strength in his left leg, and a decrease in sensation in the leg for the past month without any history of trauma. Ankle dorsiflexion and great toe extension strength on the left side were Grade I. Ankle plantar flexion and great toe flexion were Grade II. We suspected peroneal and tibial nerve palsy and performed a screening ultrasound, which is inexpensive and rapid. In the operative field, several cysts were discovered, originating at the site where the sciatic nerve splits into peroneal and tibial nerves. After successful surgical decompression and a series of rehabilitation procedures, the patient\'s neurological symptoms improved. There was no recurrence.

This article presents a case report of a 45-year-old male with neurofibromatosis type I (NF1) who developed a high-grade malignant peripheral nerve sheath tumor (MPNST) originating from a neurofibroma within the common peroneal nerve over popliteal fossa. MPNSTs are aggressive tumors associated with NF1, causing significant mortality. The patient underwent tumor resection surgery and received postoperative radiation therapy. Follow-up examinations showed no impairment of motor function and no tumor recurrence after regular MRI evaluation for four years. This article explores the challenges of distinguishing benign neurofibromas from malignant MPNST via MRI image and biopsy, and achieving a balance between tumor excision and preserving nerve functionality during surgical treatment. However, caution is warranted due to the risk of recurrence.

UNASSIGNED: Detailed knowledge of the anatomic course of the common peroneal nerve (CPN) is crucial for the surgical treatment of the posterolateral corner (PLC) of the knee.
UNASSIGNED: To investigate the relationship of the CPN to the PLC of the knee at different flexion angles.
UNASSIGNED: Descriptive laboratory study.
UNASSIGNED: Ten healthy volunteers were recruited to undergo magnetic resonance imaging (MRI) of the knee joint at knee flexion angles of 0°, 30°, 60°, 90°, and 120°. MRI scans at 3 levels (joint line, tibial cut, and fibular tip) were evaluated to determine (1) the distance from the CPN to the PLC and (2) the distances between the CPN and the anterior-posterior and medial-lateral tibial axes. A 3-dimensional model of the knee joint created from MRI scans of a single participant was used to simulate the creation of a fibular tunnel for PLC reconstruction and investigate the relationship between the CPN, fibular tunnel, and guide pin.
UNASSIGNED: The CPN moved posteromedially with increased knee flexion angles. As the flexion angle increased, the distances from the CPN to the anterior-posterior axis and the PLC increased significantly, while the distance to the medial-lateral axis decreased significantly at all 3 measurement levels. The distances between the CPN and anterior-posterior and medial-lateral axes were significantly different among the different knee flexion angles at the different measurement levels. There were no significant differences in the mean distance from the CPN to the posterolateral border of the tibial plateau between 0° and 30° of flexion at the fibular tip level (P = .953). There were statistically significant differences in the distance from the CPN to the PLC of the tibial plateau at the different measurement levels. The 3-dimensional model demonstrated that the position of the CPN relative to the guide pin and the bone tunnel undergoes changes during knee flexion.
UNASSIGNED: Changes in the knee flexion angle produced corresponding changes in the course of the CPN on the posterolateral aspect of the knee joint. The CPN moved posteromedially with increased knee flexion angles.
UNASSIGNED: Increasing the knee flexion angle during PLC reconstruction can effectively avoid direct injury of the CPN.

OBJECTIVE: 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).
CONCLUSIONS: 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.

UNASSIGNED: Common peroneal nerve (CPN) palsy after primary total knee arthroplasty represents a relatively rare but serious complication. Recently, there has been a growing interest in prophylactic CPN decompression in high-risk patients with significant combined valgus and flexion deformity. This study aimed to examine outcomes at our institution in those undergoing prophylactic CPN decompression at the time of total knee arthroplasty.
UNASSIGNED: A retrospective evaluation of a single-institution experience with selected patients at high risk for CPN palsy who underwent prophylactic nerve decompression through a separate incision at the time total knee arthroplasty was performed between July 1, 2018 and December 31, 2022. Patient demographics as well as perioperative and intraoperative clinical and radiographic measurements were collected and analyzed.
UNASSIGNED: A total of 14 patients (15 knees) met our inclusion criteria. The mean preoperative femorotibial angle was 18.6° of valgus (range 13°-22°). The mean preoperative flexion contracture was 4.3° (range 0°-25°). The patients with flexion contractures preoperatively had a mean combined valgus/flexion contracture deformity of 28.8° (range 23°-38°) . There was preservation of nerve function in all knees. No knees required subsequent operative intervention within 90 days of surgery.
UNASSIGNED: Early experience with prophylactic CPN release in our high-risk population demonstrates preservation of nerve function in all patients and is reasonable to consider in patients with a large preoperative combined valgus/flexion deformity. Further studies with larger sample sizes would be beneficial in verification of the results with this technique, as well as determining an angular deformity threshold for which CPN release should be considered.

There is a strong need for the development of core outcome sets (COS) across nerve surgery to allow for improved data synthesis, meta-analyses, and reporting consistency. Development of a core outcome set typically starts with assessing the literature for previously reported outcome measures. Common peroneal neuropathy (CPN) is the most common compressive mononeuropathy of the lower extremity and can result in pain, motor, and sensory deficits. A COS for COmmon PEroneal neuropathy (COS-COPE) is needed to improve future study design and comparison and synthesis of data. The goal of the current study was to assess the literature for outcomes reported in studies on CPN as the first step in the development of a COS.
A systematic review of the literature from 2000 to 2023 was performed utilizing PubMed and Medical Subject Headings (MeSH). Identified articles were screened according to study inclusion/exclusion criteria. Outcome measures reported in each included study were recorded and categorized into motor, sensory, pain, composite foot/ankle score, electrodiagnostics, function/disability patient-reported outcome (PRO), psychological, or other outcomes. Descriptive statistics were performed.
A total of 31 articles met criteria for inclusion. A motor outcome was reported in 26 (83.9%) studies; 12 (38.7%) reported a sensory outcome; 8 (25.8%) reported a pain outcome; 4 (12.9%) reported a composite foot/ankle score; 3 (9.7%) reported electrodiagnostics; 1 (3.2%) reported a function/disability PRO; 1 (3.2%) reported a psychological outcome; 2 (6.5%) reported an imaging outcome; 3 (9.7%) reported other outcomes. Across the studies, 29 distinct outcome measures were reported.
The outcomes reported in studies on CPN are varied and inconsistent. It is likely that a combination of motor, sensory, pain, and functional outcomes will be needed in a COS to best study CPN. These data will serve as a baseline for the ultimate development of the COS-COPE.

Variations in the anatomical division of the sciatic nerve are not uncommon. In this case report, we are presenting a rare variation of the sciatic nerve in relation to the superior gemellus and the presence of anomalous muscle. To the best of our knowledge, the anomalous communicating branches of the posterior cutaneous femoral nerve with tibial and common peroneal nerve and the presence of an anomalous muscle originating from the greater sciatic notch and inserting at ischial tuberosity have not been reported yet in the literature. This anomalous muscle found can be named as \'Sciaticotuberosus\' after its origin and insertion. Such variations hold clinical significance as they may contribute to piriformis syndrome, coccydynia, non-discogenic sciatica, and popliteal fossa block failure leading to local anesthesia toxicity and blood vessel traumatization. The current classifications of division of the sciatic nerve are based on its relation to the piriformis muscle. In our case report, the variation of the sciatic nerve in relation to the superior gemellus suggests the need for the revision of current classification systems. Category-like division of the sciatic nerve in relation to the superior gemellus muscle can be added.

Neurofibroma (NF) is a tumour of peripheral nerves, which would be seldom seen in the limbs, particularly in children\'s limbs. Soft, skin-coloured papules or small sub-mucosal nodules appear as these lesions. Neurofibroma is classified into three types: localized, diffuse, and plexiform. The vast majority of nerve injury is sporadic and localized, with an incredibly low risk of tumour formation. Neurofibromatosis can present as multiple skin lesions along with bone deformities in which a full investigation is critical where an undiscovered widespread illness may arise. This case study describes a neurofibroma on the common peroneal nerve of the left lower limb in a 6-year-old child who visited our hospital with chief complaints of pain and swelling around the left proximal leg.