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

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.

Evidence in peroneal nerve entrapment: A scoping review

BACKGROUND AND PURPOSE

Daily management of patients with foot drop due to peroneal nerve entrapment varies between a purely conservative treatment and early surgery, with no high-quality evidence to guide current practice. Electrodiagnostic (EDX) prognostic features and the value of imaging in establishing and supplementing the diagnosis have not been clearly established.

METHODS

We performed a literature search in the online databases MEDLINE, Embase, and the Cochrane Library. Of the 42 unique articles meeting the eligibility criteria, 10 discussed diagnostic performance of imaging, 11 reported EDX limits for abnormal values and/or the value of EDX in prognostication, and 26 focused on treatment outcome.

RESULTS

Studies report high sensitivity and specificity of both ultrasound (varying respectively from 47.1% to 91% and from 53% to 100%) and magnetic resonance imaging (MRI; varying respectively from 31% to 100% and from 73% to 100%). One comparative trial favoured ultrasound over MRI. Variable criteria for a conduction block (>20%-≥50) were reported. A motor conduction block and any baseline compound motor action potential response were identified as predictors of good outcome. Based predominantly on case series, the percentage of patients with good outcome ranged 0%-100% after conservative treatment and 40%-100% after neurolysis. No study compared both treatments.

CONCLUSIONS

Ultrasound and MRI have good accuracy, and introducing imaging in the standard diagnostic workup should be considered. Further research should focus on the role of EDX in prognostication. No recommendation on the optimal treatment strategy of peroneal nerve entrapment can be made, warranting future randomized controlled trials.

Electrodiagnosis of Common Mononeuropathies: Median, Ulnar, and Fibular (Peroneal) Neuropathies

This article addresses common mononeuropathies seen in the electrodiagnostic laboratory. The most common mononeuropathies-median neuropathy at the wrist (carpal tunnel syndrome), ulnar neuropathy at the elbow, and fibular (peroneal) neuropathy at the fibular head-are reviewed. The causes, clinical presentations, approached to the electrodiagnostic studies (including nerve conduction studies and needle electromyography), and the typical findings are discussed.

Bilateral common peroneal neuropathy due to rapid and marked weight loss after biliary surgery: A case report

BACKGROUND

The causes of peroneal neuropathy are various, but are rarely due to weight loss. Bilateral peroneal neuropathy caused by weight loss after surgery has been reported only after bariatric surgery and there were no reports associated with other abdominal surgery. In this report, we describe a case of the bilateral peroneal neuropathy that occurred due to marked weight loss after biliary surgery.

CASE SUMMARY

A 58-year-old male did not receive adequate nutritional support after biliary surgery, and showed a massive weight loss over a short period of time (body mass index; 24.1 kg/m² to 20.5 kg/m² for 24 d). Then, foot drop occurred on both sides. Physical examination, electromyography (EMG) and magnetic resonance imaging studies were conducted and he was diagnosed as bilateral common peroneal neuropathy around the fibular head level. The patient was treated electrical stimulation therapy on both lower legs along with exercise therapy, and received sufficient oral nutritional support. The patient gradually recovered to his original weight, and the power of the dorsiflexor of bilateral ankles improved after conservative treatment. In addition, the follow-up EMG showed signs of improvement.

CONCLUSION

Any abdominal surgery that may have rapid and marked weight loss can lead to peroneal neuropathy as a complication.

Evaluation and Treatment of Foot Drop Using Nerve Transfer Techniques

Foot drop represents a complex pathologic condition, requiring a multidisciplinary approach for appropriate evaluation and treatment. Multiple etiologic factors require recognition before considering invasive/operative intervention. When considering surgical management for the treatment of foot drop, it is first and foremost imperative to establish the cause of the condition. Not all causes resulting in clinical foot drop have surgical options. Establishing a cause allows the provider to more appropriately curtail a multidisciplinary approach to working-up, and ultimately, treating the patient. The authors offer an algorithm for evaluating and treating foot drop conditions associated with lumbar spine radiculopathy and peripheral nerve lesions.

Role of nerve ultrasound versus electrophysiological studies in the evaluation of nerve injuries

Background

High-resolution ultrasonography (US) is a non-invasive, readily applicable imaging modality capable of depicting real-time static and dynamic information concerning the peripheral nerves and their surrounding tissues. Although electrophysiological studies are the gold standard in the evaluation of nerve injuries, US can be used also to evaluate the morphological changes of nerve injuries.

Objectives

To evaluate the role of the high-resolution US in the assessment of nerve injuries and to compare it to the role of electrodiagnostic studies.

Subjects and methods

A total of 30 nerves from 22 consecutive patients with clinically definite nerve injury were considered. Two independent and blinded clinicians perform electrodiagnosis and US. The clinical, neurophysiological, and US findings were collected, and the contribution of US was then classified as “ contributive” or “non-contributive”, according to whether US confirmed the clinical and neurophysiological diagnosis or not.

Results

US was “contributive” (confirming the electrophysiological diagnosis) in 66.67% of cases (n = 20), providing information about continuity of the nerve, morphological changes after injury as swelling, scar tissue formation, or neuroma formation with sensitivity of 75% compared to the electrodiagnostic studies and accuracy of 66.67%.

Conclusion

Ultrasound can be used, when available, as a complementary tool for electrodiagnostic studies to provide anatomical information about the injured nerves in case of complete axonal lesion.

Current and future applications of ultrasound imaging in peripheral nerve disorders

Neuromuscular ultrasound (NMUS) is a rapidly evolving technique used in neuromuscular medicine to provide complimentary information to standard electrodiagnostic studies. NMUS provides a dynamic, real time assessment of anatomy which can alter both diagnostic and management pathways in peripheral nerve disorders. This review describes the current and future techniques used in NMUS and details the applications and developments in the diagnosis and monitoring of compressive, hereditary, immune-mediated and axonal peripheral nerve disorders, and motor neuron diseases. Technological advances have allowed the increased utilisation of ultrasound for management of peripheral nerve disorders; however, several practical considerations need to be taken into account to facilitate the widespread uptake of this technique.

The Interdisciplinary Management of Foot Drop

BACKGROUND

Foot drop can be caused by a variety of diseases and injuries. Although it is a common condition, its overall incidence has not been reported to date. Foot drop markedly restricts the everyday activities of persons suffering from it. There is, therefore, a need for an optimized strategy for its diagnosis and treatment that would be standardized across the medical specialties encountering patients with this problem.

METHODS

This article consists of a review on the basis of pertinent publications re- trieved by a search in the Pubmed/MEDLINE and Cochrane databases, as well as a description of the authors' proposed strategy for the diagnosis and treatment of foot drop.

RESULTS

Foot drop can be due to a disturbance at any central or peripheral location along the motor neural pathway that terminates in the dorsiflexor muscles of the foot, or at multiple locations in series. Optimal localization of the lesion(s) is a pre- requisite for appropriate treatment and a successful outcome. The most common causes are L5 radiculopathy and peroneal nerve injury. An operation by a neuro- surgeon or spinal surgeon is a reasonable option whenever there is a realistic chance that the nerve will recover. In our opinion, any patient with a subjectively disturbing foot drop and a clinically suspected compressive neuropathy of the peroneal nerve should be informed about the option of surgical decompression of the nerve at the fibular head, which can be performed with little risk. In case of a permanent foot drop, some patients can benefit from muscle-transfer surgery. For spastic foot drop, the option of botulinum toxin injections should be evaluated.

CONCLUSION

The care of patients with foot drop could be optimized by interdisciplin- ary foot-drop clinics involving all of the relevant specialists. The goals of treatment should always be improved mobility in everyday life and the prevention of falls, pain, and abnormal postures.

Imaging of Damaged Nerves

Nerve imaging is an important component in the assessment of patients presenting with suspected peripheral nerve pathology. Although magnetic resonance neurography and ultrasound are the most commonly utilized techniques, several promising new modalities are on the horizon. Nerve imaging is useful in localizing the nerve injury, determining the severity, providing prognostic information, helping establish the diagnosis, and helping guide surgical decision making. The focus of this article is imaging of damaged nerves, focusing on nerve injuries and entrapment neuropathies.

Conduction Block and Nerve Cross-Sectional Area in Multifocal Motor Neuropathy

Introduction: Motor nerve conduction block (CB) is the main electrophysiological feature of multifocal motor neuropathy (MMN). Increased cross-sectional area (CSA) can be detected by nerve ultrasound in MMN. In this study, we aim to analyze the correlation between CB and CSA in MMN.

Methods: Twelve patients with MMN were recruited. Ultrasonography tests and motor nerve conduction studies (NCSs) were performed on median and ulnar nerves simultaneously. CSA was measured at 10 consecutive sites on those nerves, meanwhile nerves were traced continuously and recorded thoroughly under ultrasound.

Results: In motor NCSs, 12 definite CB and 12 probable CB areas were detected across standard segments of median and ulnar nerves. With ultrasound studies, increased CSA was detected at 36 sites. There were 9 standard segments with CB and increased CSA, 15 segments with CB but normal CSA, and 27 segments with increased CSA but no CB.

Discussion: In MMN, motor nerve CB was not always consistent with increased CSA.

Common Entrapment Neuropathies

PURPOSE OF REVIEW

This article addresses relevant peripheral neuroanatomy, clinical presentations, and diagnostic findings in common entrapment neuropathies involving the median, ulnar, radial, and fibular (peroneal) nerves.

RECENT FINDINGS

Entrapment neuropathies are a common issue in general neurology practice. Early diagnosis and effective management of entrapment mononeuropathies are essential in preserving limb function and maintaining patient quality of life. Median neuropathy at the wrist (carpal tunnel syndrome), ulnar neuropathy at the elbow, radial neuropathy at the spiral groove, and fibular neuropathy at the fibular head are among the most frequently encountered entrapment mononeuropathies. Electrodiagnostic studies and peripheral nerve ultrasound are employed to help confirm the clinical diagnosis of nerve compression or entrapment and to provide precise localization for nerve injury. Peripheral nerve ultrasound demonstrates nerve enlargement at or near sites of compression.

SUMMARY

Entrapment neuropathies are commonly encountered in clinical practice. Accurate diagnosis and effective management require knowledge of peripheral neuroanatomy and recognition of key clinical symptoms and findings. Clinical diagnoses may be confirmed by diagnostic testing with electrodiagnostic studies and peripheral nerve ultrasound.

Sonography of Carpal Tunnel Syndrome According to Pathophysiologic Type: Conduction Block Versus Axonal Degeneration

OBJECTIVES

The purpose of this study was to investigate sonographic findings according to the pathophysiologic type in patients with carpal tunnel syndrome.

METHODS

We retrospectively reviewed the records of 80 patients (148 hands) with carpal tunnel syndrome. Patients were classified into 3 groups according to electrophysiologic findings: (1) conduction block and conduction delay; (2) axonal degeneration; and (3) mixed. We used sonographic evaluations to assess the cross-sectional area at the distal wrist crease and the distal forearm and the wrist-to-forearm ratio of the median nerve.

RESULTS

Patients with axonal degeneration had significantly larger cross-sectional areas and wrist-to-forearm ratios than those with a conduction block (P < .05). The increased wrist-to-forearm ratio correlated with a reduced amplitude of the sensory nerve action potential, which reflects the degree of axonal degeneration.

CONCLUSIONS

The cross-sectional area and wrist-to-forearm ratio were associated with the pathophysiologic type of carpal tunnel syndrome, with larger nerve swellings seen in patients with axonal degeneration compared with those with demyelinating lesions. In addition to helping in the localization of the nerve lesion, sonography may indicate the type of nerve lesion.

Ultrasound versus MRI in common fibular neuropathy

INTRODUCTION

We prospectively compared ultrasound (US) and MRI in patients with common fibular neuropathy.

METHODS

Forty adult patients with clinical suspicion of common fibular neuropathy and 40 healthy controls underwent both US and MRI. US and MRI datasets were randomized for prospective reading.

RESULTS

The overall sensitivity of US and MRI for diagnosing fibular neuropathy was 90% (95% confidence interval [CI], 79.7%-97.3%) and 87.5% (95% CI, 71.55%-93.1%), respectively. The overall specificity of US and MRI was 92% (95% CI, 77.45%-96.1%) and 85% (95% CI, 73.3%-94.4%), respectively. The overall sensitivity and specificity of US combined with MRI were 94% (95% CI, 0.80%-0.99%) and 84% (95% CI, 0.70%-0.91%), respectively. Overall intra- and inter-observer agreements among 3 readers were 0.76% (95% CI, 0.62%-0.85%) and 0.74% (95% CI, 0.65%-0.81%).

CONCLUSIONS

US diagnostic accuracy for common fibular neuropathy was slightly higher than that of MRI. Muscle Nerve 55: 849-857, 2017.

Diagnostic Cutoff Value for Ultrasonography of the Common Fibular Neuropathy at the Fibular Head

Objective

To establish the diagnostic cutoff value of ultrasonographic measurement for common fibular neuropathy (CFN) at the fibular head (FH).

Methods

Twenty patients with electrodiagnostically diagnosed CFN at the FH and 30 healthy controls were included in the study. The cross-sectional area (CSA) of sciatic nerve at mid-thigh level, common fibular nerve at popliteal fossa (PF), and common fibular (CF) nerve at FH were measured. Additionally, the difference of CF nerve CSA at the FH between symptomatic side and asymptomatic side (ΔSx–Asx), the ratio of CF nerve CSA at FH to at PF (FH/PF), and the ratio of CF nerve CSA at the FH symptomatic side to asymptomatic side (Ratio Sx–Asx) were calculated.

Results

CSA at the FH, FH/PF, ΔSx–Asx, and Ratio Sx–Asx showed significant differences between the patient and control groups. The cutoff value for diagnosing CFN at the FH was 11.7 mm² for the CSA at the FH (sensitivity 85.0%, specificity 90.0%), 1.70 mm² for the ΔSx–Asx (sensitivity 83.3%, specificity 97.0%), 1.11 for the FH/PF (sensitivity 47.1%, specificity 93.3%), and 1.24 for the Ratio Sx–Asx (sensitivity 72.2%, specificity 96.7%).

Conclusion

The ultrasonographic measurement and cutoff value could be a valuable reference in diagnosing CFN at the FH and improving diagnostic reliability and efficacy.

Update in Musculoskeletal Ultrasound Research

CONTEXT

Musculoskeletal ultrasound (US) research is expanding due to increased clinical utility of sonography.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

Ultrasound is widely applied in musculoskeletal imaging and sports medicine. The real-time capabilities and favorable cost profile of US make it ideal for use in diagnosis of musculoskeletal conditions. The enthusiasm for the use of US in musculoskeletal imaging has led to an increase in US research to broaden its applications.

CONCLUSION

Several recent advances have been made in conventional and novel US imaging techniques, quantitative US imaging, and US-guided interventions.

STRENGTH OF RECOMMENDATIONS TAXONOMY SORT

C.

Peripheral nerve imaging

Disorders of peripheral nerve have been traditionally diagnosed and monitored using clinical and electrodiagnostic approaches. The last two decades have seen rapid development of both magnetic resonance imaging (MRI) and ultrasound imaging of peripheral nerve, such that these imaging modalities are increasingly invaluable to the diagnosis of patients with peripheral nerve disorders. Peripheral nerve imaging provides information which is supplementary to clinical and electrodiagnostic diagnosis. Both MRI and ultrasound have particular benefits in specific clinical circumstances and can be considered as complementary techniques. These technologic developments in peripheral nerve imaging will usher in an era of multimodality assessment of peripheral nerve disorders, with clinical evaluations supported by anatomic information from imaging, and functional information from electrodiagnostic studies. Such a multimodality approach will improve the accuracy and efficiency of patient care.

Nerve Ultrasound in Peripheral Neuropathies: A Review

Peripheral neuropathies are one of the most common reasons for seeking neurological care in everyday practice. Electrophysiological studies remain fundamental for the diagnosis and etiological classification of peripheral nerve impairment. The recent technological development though of high resolution ultrasound has allowed the clinician to obtain detailed structural images of peripheral nerves. Nerve ultrasound mainly focuses on the evaluation of the cross sectional area, cross sectional area variability along the anatomical course, echogenity, vascularity and mobility of the peripheral nerves. An increase of the cross sectional area, hypervascularity, disturbed fascicular echostructure and reduced nerve mobility are some of the most common findings of entrapments neuropathies, such as the carpal or cubital tunnel syndrome. Both the cross-sectional area increase and the hypervascularity detected with the Doppler technique seem to correlate significantly with the clinical and electrophysiological severity of the later mononeuropathies. Significantly greater cross sectional area values of the clinically affected cervical nerve root are often detected in cases of cervical radiculopathy. In such cases, the ultrasound findings seem also to correlate significantly with disease duration. On the other hand, multifocal cross sectional area enlargement of cervical roots and/or peripheral nerves is often documented in cases of immune-mediated neuropathies. None of the later pathological ultrasound findings seem to correlate significantly with the electrophysiological parameters or the functional disability. The aim of this review is to provide a timely update on the role of neuromuscular ultrasound in the diagnostic of the most common entrapment and immune-mediated peripheral neuropathies in clinical practice.

Nerve ultrasound depicts peripheral nerve enlargement in patients with genetically distinct Charcot-Marie-Tooth disease

OBJECTIVE

To elucidate the ultrasound (US) features of peripheral nerves including nerve roots in patients with different types of Charcot-Marie-Tooth disease (CMT), and the association between US findings, clinical features and parameters of nerve conduction studies (NCS) in CMT1A.

METHODS

US of median, sural and great auricular nerves and the C6 nerve root was performed in patients with CMT1A (n=20), MPZ-associated CMT (n=3), NEFL-associated CMT (n=4), EGR2-associated CMT (n=1), ARHGEF10-associated CMT (n=1) and in controls (n=30). In patients with CMT1A, we analysed the correlations between US findings and the following parameters: age, CMT Neuropathy Score (CMTNS) and NCS indices of the median nerve.

RESULTS

Cross-sectional areas (CSAs) of all the nerves were significantly increased in patients with CMT1A compared with that in controls. In MPZ-associated CMT, increased CSAs were found in the median nerve at wrist and in the great auricular nerve, whereas it was not increased in patients with NEFL-associated CMT. In patients with CMT1A, there was a positive correlation between CMTNS and the CSAs in the median nerves or great auricular nerves. In median nerves in patients with CMT1A, we found a negative correlation between the nerve conduction velocity and the CSA.

CONCLUSIONS

Nerve US may aid in differentiating among the subtypes of CMT in combination with NCS. In CMT1A, the median nerve CSA correlates with the disease severity and peripheral nerve function.