An Update on Peroneal Nerve Entrapment and Neuropathy

Peroneal Nerve Entrapment in Diabetes Mellitus

This narrative mini-review discusses the association between peroneal nerve entrapment (PEN) and diabetes mellitus (DM). Generally, PEN is not a common cause of peripheral neuropathy in DM. Poor glycaemic control and DM duration are powerful risk factors for PEN. Underlying mechanisms involve neurodegeneration and entrapment of the peroneal nerve. Patients tend to present with chronic leg pain, gradual foot drop, steppage gait, or weakness of ankle dorsiflexion. Electrodiagnostic and imaging studies are very useful in diagnosis to determine the level at which entrapment occurs. Treatment varies based on the aetiology and severity of symptoms. It is initially conservative. Surgical nerve decompression management is required when entrapment is refractory to non-operative options.

Peripheral nerve injuries in the performing artist

Dancers and musicians have unique physical demands that can lead to injury of the peripheral nerves. Specific dance movements and specific instrument positions, combined with countless hours of practice and repetition, create an environment for potential nerve injury. Familiarity with these variables and recognition of the common presentations of neuropathic syndromes are essential in the evaluation of a performing artist with a suspected peripheral nerve injury. Assessment should include an understanding and analysis of their dance style or instrument playing posture, particularly in the position or motion that recreates the symptoms if possible. Practice and performance schedules should also be considered. Diagnosis may require electrodiagnostic testing, imaging, or diagnostic injections. Treatment should be comprehensive and may include modifications in practice schedule, posture/position, and technique in addition to consideration of medications, splints/orthoses, physical therapy, and injections. The instructor/teacher should be involved in the treatment plan if applicable. Complete rest in this population may not be realistic or necessary. Early and accurate diagnosis of nerve injury is important for safe return to dance or instrumental music.

Palsy of Both the Tibial Nerve and Common Peroneal Nerve Caused by a Ganglion Cyst in the Popliteal Area

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.

Nonalcoholic Fatty Liver Disease in Shift Workers and Its Effect on Peripheral Nerve Conduction: A Cross-Sectional Study

Introduction Nonalcoholic fatty liver disease (NAFLD) presents as a multisystem disorder, heightening the risk of developing type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVDs). Occupation emerges as a significant factor influencing the occurrence of NAFLD. Research indicates that individuals engaged in shift work face an elevated risk of NAFLD, alongside obesity and T2DM, attributed to disruptions in their circadian rhythm, which precipitate hepatic steatosis and inflammation. Remarkably, peripheral neuropathy has been observed in conjunction with advanced liver disorders and NAFLD in the general population. However, the correlation between NAFLD and peripheral neuropathy remains unestablished in shift workers. Objective To identify NAFLD in seemingly healthy rotating shift workers and assess any potential impact of NAFLD on nerve function in this demographic. Methods This cross-sectional study involved 73 apparently healthy nonalcoholic security guards (aged 35 to 60 years) working in rotating shifts. The study included a comprehensive assessment, beginning with a medical history, an evaluation of physical activity, and anthropometric measurements. Confirmation of NAFLD was achieved through abdominal ultrasonography (USG), followed by the analysis of biochemical parameters. Motor and sensory nerve conduction studies (NCS) were conducted on participants with normal vitamin B12 levels using the Aleron electromyograph (EMG) machine (Recorders and Medicare Systems Private Ltd, Budanpur, India). The evaluation encompassed the Median and Common Peroneal motor nerves, as well as Median and Sural sensory nerves. Recorded parameters for motor nerves included distal motor latency (DML), compound muscle action potential (CMAP) amplitude, conduction velocity (CV), and F-wave minimum latency (F-wave), while sensory nerve parameters comprised sensory onset latency (SOL), sensory nerve action potential (SNAP) amplitude, and CV. Results Among 73 healthy security guards working in rotating shifts, 76.1% were diagnosed with NAFLD through abdominal ultrasound. Following participant withdrawals and exclusions due to vitamin B12 deficiency, a comparison of NCS parameters between NAFLD (n=24) and Non-NAFLD (n=12) groups revealed no significant disparities in motor or sensory parameters, except for a slightly diminished CMAP amplitude in the peroneal nerve of NAFLD subjects (8.21±2.83mV vs ±10.22±2.30 mV, p< 0.040). However, these differences fell within normal ranges, indicating no notable impact on peripheral nerve conduction in the presence of NAFLD. Conclusion The results indicate a high prevalence of NAFLD among individuals working rotating shifts. Moreover, the investigation suggests that despite the presence of NAFLD, there is no discernible influence on motor and sensory peripheral nerve conduction, particularly in common peroneal, median, and sural nerves.

Electrophysiological Screening to Assess Foot Drop Syndrome in Severe Acquired Brain Injury in Rehabilitative Settings

BACKGROUND

Foot drop syndrome (FDS), characterized by severe weakness and atrophy of the dorsiflexion muscles of the feet, is commonly found in patients with severe acquired brain injury (ABI). If the syndrome is unilateral, the cause is often a peroneal neuropathy (PN), due to compression of the nervous trunk on the neck of the fibula at the knee level; less frequently, the cause is a previous or concomitant lumbar radiculopathy. Bilateral syndromes are caused by polyneuropathies and myopathies. Central causes, due to brain or spinal injury, mimic this syndrome but are usually accompanied by other symptoms, such as spasticity. Critical illness polyneuropathy (CIP) and myopathy (CIM), isolated or in combination (critical illness polyneuromyopathy, CIPNM), have been shown to constitute an important cause of FDS in patients with ABI. Assessing the causes of FDS in the intensive rehabilitation unit (IRU) has several limitations, which include the complexity of the electrophysiological tests, limited availability of neurophysiology consultants, and the severe disturbance in consciousness and lack of cooperation from patients.

OBJECTIVES

We sought to propose a simplified electrophysiological screening that identifies FDS causes, particularly PN and CIPNM, to help clinicians to recognize the significant clinical predictors of poor outcomes in severe ABI at admission to IRU.

METHODS

This prospective, single-center study included 20 severe ABI patients with FDS (11 females/9 males, mean age 55.10 + 16.26; CRS-R= 11.90 + 6.32; LCF: 3.30 + 1.30; DRS: 21.45 + 3.33), with prolonged rehabilitation treatment (≥2 months). We applied direct tibialis anterior muscle stimulation (DMS) associated with peroneal nerve motor conduction evaluation, across the fibular head (NCS), to identify CIP and/or CIM and to exclude demyelinating or compressive unilateral PN.

RESULTS

At admission to IRU, simplified electrophysiological screening reported four unilateral PN, four CIP and six CIM with a CIPNM overall prevalence estimate of about 50%. After 2 months, the CIPNM group showed significantly poorer outcomes compared to other ABI patients without CIPNM, as demonstrated by the lower probability of achieving endotracheal-tube weaning (20% versus 90%) and lower CRS-R and DRS scores. Due to the subacute rehabilitation setting of our study, it was not possible to evaluate the motor results of recovery of the standing position, functional walking and balance, impaired by the presence of unilateral PN.

CONCLUSIONS

The implementation of the proposed simplified electrophysiological screening may enable the early identification of unilateral PN or CIPNM in severe ABI patients, thereby contributing to better functional prognosis in rehabilitative settings.

Sciatic and tibial neuropathies

The sciatic nerve is the body's largest peripheral nerve. Along with their two terminal divisions (tibial and fibular), their anatomic location makes them particularly vulnerable to trauma and iatrogenic injuries. A thorough understanding of the functional anatomy is required to adequately localize lesions in this lengthy neural pathway. Proximal disorders of the nerve can be challenging to precisely localize among a range of possibilities including lumbosacral pathology, radiculopathy, or piriformis syndrome. A correct diagnosis is based upon a thorough history and physical examination, which will then appropriately direct adjunctive investigations such as imaging and electrodiagnostic testing. Disorders of the sciatic nerve and its terminal branches are disabling for patients, and expert assessment by rehabilitation professionals is important in limiting their impact. Applying techniques established in the upper extremity, surgical reconstruction of lower extremity nerve dysfunction is rapidly improving and evolving. These new techniques, such as nerve transfers, require electrodiagnostic assessment of both the injured nerve(s) as well as healthy, potential donor nerves as part of a complete neurophysiological examination.

Diagnostic Approach to Lower Limb Entrapment Neuropathies: A Narrative Literature Review

Entrapment neuropathies of the lower limb are a misunderstood and underdiagnosed group of disorders, characterized by pain and dysesthesia, muscular weakness, and specific provoking movements on physical examination. The most frequent of these syndromes encountered in clinical practice are fibular nerve entrapment, proximal tibial neuropathy, sural nerve neuropathy, deep gluteal syndrome or sciatic nerve entrapment, and lateral femoral cutaneous nerve entrapment, also known as meralgia paresthetica. These are commonly mistaken for lumbar plexopathies, radiculopathies, and musculotendinous diseases, which appear even more frequently and have overlapping clinical presentations. A comprehensive anamnesis, physical examination, and electrodiagnostic studies should help clarify the diagnosis. If the diagnosis is still unclear or a secondary cause of entrapment is suspected, magnetic resonance neurography, MRI, or ultrasonography should be conducted to clarify the etiology, rule out other diseases, and confirm the diagnosis. The aim of this narrative review was to help clinicians gain familiarity with this disease, with an increase in diagnostic confidence, leading to early diagnosis of nerve damage and prevention of muscle atrophy. We reviewed the epidemiology, anatomy, pathophysiology, etiology, clinical presentation, and EDX technique and interpretation of the entrapment neuropathies of the lower limb, using articles published from 1970 to 2022 included in the Pubmed, MEDLINE, Cochrane Library, Google Scholar, EMBASE, Web of Science, and Scopus databases.

Entrapment neuropathy of common peroneal nerve by fabella: A case report

BACKGROUND

Neuropathy of the common peroneal nerve caused by compression by a fabella is an extremely rare form of compression neuropathy. Involving both the superficial and deep peroneal nerves, it usually manifests as either impaired sensation from the lower lateral leg to the top of the foot or drop foot, or as a combination of both.

CASE SUMMARY

We report the case of a 58-year-old Asian female who presented with inversion of the right foot during the stance phase of gait without sensory complaints related to the lower leg. Electrodiagnostic testing revealed the neuropathy of the common peroneal nerve at the level of the knee, exclusively affecting the muscular branch of the superficial peroneal nerve. A neuromuscular ultrasound disclosed swelling of the right common peroneal nerve just before it crossed over a large fabella as well as atrophy and fatty infiltration of the right peroneus longus and peroneus brevis muscles. Surgical excision of the fabella and neurolysis were performed. Subsequently, the strength of the right foot evertors improved, but the unsteady gait with occasional falls persisted for nine months after the surgery. Therefore, another procedure was performed to transfer the split posterior tibialis tendon to the peroneus brevis in order to correct the gait.

CONCLUSION

This is the first case of neuropathy of the common peroneal nerve caused by compression by a fabella affecting exclusively the muscular branch of the superficial peroneal nerve. Clinicians should be aware of this unusual peripheral neuropathy while evaluating and treating patients with gait disturbance.

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.

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.

Ultrasound-Guided Pulsed Radiofrequency Treatment for Superficial Peroneal Nerve Entrapment in a Professional Handball Player

Peripheral nerve injury in athletes is rare but deleterious to their performance, entrapment being one of the most frequent causes. Isolated injury to the superficial peroneal nerve (SPN) is rare and often underdiagnosed. The authors reported a clinical case of a 34-year-old handball athlete who presented with neuropathic pain in the inferolateral third of the leg and dorsum of the foot, with three months of evolution, after an ankle sprain, refractory to conservative treatment. After clinical assessment and ultrasound investigation, it was considered that the pain source was likely to be an SPN entrapment. Thus, a diagnostic ultrasound-guided nerve block with 2ml of 2% lidocaine and 3ml of 0.2% ropivacaine was performed, followed by nerve hydrodissection, with a major improvement in the patient's symptoms and functionality for three weeks. Thereafter, a long-lasting alternative was made - pulsed radiofrequency (pRF). There were no complications after the procedure. As a form of neuromodulation, pRF offered pain resolution without tissue damage or painful sequela, after 3, 6, 12, and 24 months of follow-up and complete participation in sports activity, avoiding surgical treatment. With this clinical case, the authors intend to demonstrate the effectiveness of pRF in the resolution of peripheral neuropathy due to entrapment, avoiding more invasive treatment options and, in the case of an athlete, allowing an early return to play. They also intend to corroborate the advantage of using ultrasound in the diagnosis and guide of minimally invasive procedures.

Longitudinal Movements and Stiffness of Lower Extremity Nerves Measured by Ultrasonography and Ultrasound Elastography in Symptomatic and Asymptomatic Populations: A Systematic Review With Meta-analysis

This study was aimed at analyzing the effectiveness of ultrasonography (US) and ultrasound elastography (UE) in evaluating longitudinal sliding and stiffness of nerves. In line with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement, we analyzed 1112 publications (range: 2010-2021) extracted from MEDLINE, Scopus and Web of Science focusing on specific outcomes, including shear wave velocity (m/s), shear modulus (kPa), strain ratio (SR) and excursion (mm). Thirty-three papers were included and evaluated for overall quality and risk of bias. From the analysis of data concerning 1435 participants, mean shear wave velocity (SWV) in the sciatic nerve was 6.70 ± 1.26 m/s in controls and 7.51 ± 1.73 m/s in participants presenting with leg pain; in the tibial nerve, mean SWV was 3.83 ± 0.33 m/s in controls and 3.42 ± 3.53 m/s in participants presenting with diabetic peripheral neuropathy (DPN). The mean shear modulus (SM) was 20.9 ± 9.33 kPa for sciatic nerve, whereas it was an average of 23.3 ± 7.20 kPa for the tibial nerve. Considering 146 subjects (78 experimental, 68 controls) no significant difference was observed in SWV when comparing participants with DPN with controls (standard mean difference [SMD]: 1.26, 95% confidence interval [CI]: 0.54, 1.97), whereas a significant difference was observed in the SM (SMD: 1.78, 95% CI: 1.32, 2.25); furthermore, we found significant differences between left and right extremity nerves (SMD:1.14. 95% CI: 0.45, 1.83) among 458 participants (270 with DPN and 188 controls). No descriptive statistics are available for excursion because of the variability in participants and limb positions, whereas SR is considered only a semiquantitative outcome and therefore not comparable among different studies. Despite the presence of some limitations in study designs and methodological biases, on the basis of our findings, we can conclude that US and UE are effective methods in assessing longitudinal sliding and stiffness of lower extremity nerves in both symptomatic and asymptomatic subjects.

Ultrasound as a Useful Tool for a Peripheral Nerve Surgeon: Examples in Clinical Practice

BACKGROUND

 Peripheral nerve surgeons often require additional imaging for examination, diagnostic testing, and preoperative planning. Point-of-care ultrasound (US) is a cost-effective, accessible, and well-established technique that can assist the surgeon in diagnosing and treating select peripheral nerve pathologies. With this knowledge, the properly trained surgeon may perform US-guided nerve blocks to help accurately diagnose and treat causes of neuropathic pain. We offer this paper, not as an exhaustive review, but as a selection of various peripheral nerve pathologies, which the senior author treats, and their associated US examination findings. Our goal is to encourage other peripheral nerve surgeons to incorporate US into their practices.

METHODS

 We provide various cases from our outpatient peripheral nerve clinic demonstrating relevant US anatomy. We also review techniques for US guided nerve blocks with relevant anatomic landmarks.

RESULTS

 US imaging successfully assisted in identification and injection techniques for various peripheral nerve pathologies in a surgeon's practice. Examples were presented from the neck, trunk, upper extremity, and lower extremity.

CONCLUSION

 Our review highlights the use of US by a peripheral nerve surgeon in an outpatient private practice clinic to diagnose and treat select peripheral nerve pathologies. We encourage reconstructive surgeons to add US to their arsenal of diagnostic tools.

Extracellular matrix deformations of the porcine recurrent laryngeal nerve in response to hydrostatic pressure

Damage to the recurrent laryngeal nerve (RLN) caused by supraphysiological compression or tension imposed by adjacent tissue structures, such as the aorta, may contribute to onset of idiopathic unilateral vocal fold paralysis (iUVP) resulting in difficulty speaking, breathing, and swallowing. We previously demonstrated in adolescent pigs that the right RLN epineurium exhibits uniform composition of adipose tissue, with larger quantities along its length within the neck region in contrast to the left RLN that shows greater collagen composition in the thoracic region and greater quantities of adipose tissue in the neck region. In contrast, the epineurium in piglets was primarily composed of collagen tissue that remained uniform along the length of the left and right RLNs. Tensile testing of the left and right RLN in piglets and pigs showed associated differences in strain by RLN side and segment by age. The goal of this study was to investigate how external hydrostatic compression of the RLN affects the nerve's connective tissue and microstructure. RLN segments were harvested from the distal (cervical/neck) regions and proximal (subclavian for the right RLN, thoracic for the left RLN) regions from eight adolescent pigs and nine piglets. RLN segments were isolated and assessed under fluid compression to test hypotheses regarding epineurium composition and response to applied forces. Second harmonic generation (SHG) imaging of epineurial collagen was conducted at 0, 40, and 80 mmHg of compression. The cartesian strain tensor, principal strain (Eps1), and principal direction of the RLN collagen fibers were determined at each pressure step. Significantly larger values of the 1st principal strain occurred in the proximal segments of the pig left RLN when compared to the same segment in piglets (p = 0.001, pig = 0.0287 [IQR = 0.0161 - 0.0428], piglet = 0.0061 [IQR = 0.0033 - 0.0156]). Additionally, the median transverse strain Eyy) for the second pressure increment was larger in the right proximal segment of pigs compared to piglets (p < 0.001, pig = 0.0122 [IQR = 0.0033 - 0.0171], piglet = 0.0013 [IQR = 0.00001 - 0.0028]). Eyy values were significantly larger in the right proximal RLN versus the left proximal RLNs in pigs but not in piglets (p < 0.001). In contrast to piglets, histological analysis of pig RLN demonstrated increased axial alignment of epineurial and endoneurial collagen in response to compressive pressure. These findings support the hypothesis that the biomechanical response of the RLN to compressive pressure changed from being similar to being different between the right and left RLNs during development in the porcine model. Further investigation of these findings associated with age-related onset of idiopathic UVP may illuminate underlying etiologic mechanisms. STATEMENT OF SIGNIFICANCE: Damage to the recurrent laryngeal nerve (RLN) caused by compression imposed by the aorta may contribute to the onset of left-sided idiopathic unilateral vocal fold paralysis resulting in difficulty speaking, breathing, and swallowing. The goal of this study was to investigate how compression affects the connective tissue and microstructure of the RLN. We quantified the pressure induced deformation of the RLN using multiphoton imaging as a function of both location (proximal versus distal) and age (piglets, adolescent pigs). Our results demonstrate that the biomechanical response of the RLN to compression changes in the right versus left RLN throughout development, providing further evidence that the the left RLN is exposed to increasing dynamic loads with age.

Biological Approach in the Treatment of External Popliteal Sciatic Nerve (Epsn) Neurological Injury: Review

The external popliteal sciatic nerve (EPSN) is the nerve of the lower extremity most frequently affected by compressive etiology. Its superficial and sinuous anatomical course is closely related to other rigid anatomical structures and has an important dynamic neural component. Therefore, this circumstance means that this nerve is exposed to multiple causes of compressive etiology. Despite this fact, there are few publications with extensive case studies dealing with treatment. In this review, we propose to carry out a narrative review of the neuropathy of the EPSN, including an anatomical reminder, its clinical presentation and diagnosis, as well as its surgical and biological approach. The most novel aspect we propose is the review of the possible role of biological factors in the reversal of this situation.