Nerve biopsy: Current indications and decision tools

Biopsy of the anterior interosseous motor branch for the pronator quadratus muscle: a safe and minimally invasive diagnostic tool for peripheral neuropathies. Anatomical surgery and surgical technique

BACKGROUND AND OBJECTIVES

Choosing the correct site for a nerve biopsy remains a challenge due to nerve sacrifice and major donor site complications, such as neuroma, as seen in sural nerve biopsy. Selecting a deeper donor nerve can help in burying nerve stumps in deep soft tissues, preventing neuroma. Moreover, using an expendable, deeply situated motor nerve can aid indiagnosis when a motor neuropathy is suspected. The authors propose using the pronator quadratus (PQ) branch for this purpose, as it is located deep between the bellies of the flexor muscles and the interosseous membrane in the forearm. This branch is expendable since the denervation of the PQ has a negligible effect on forearm pronation, which is primarily sustained by the pronator teres.

METHODS

The surgical approach is the same as the approach for anterior interosseous nerve transfer to the motor component of the ulnar nerve in the distal forearm: access is in the midline in the middle third of the forearm under local anesthesia Blunt dissection is performed, separating and retracting the flexor musculotendinous junction to reach the interosseous membrane where the PQ branch is identified. A careful dissection of the nerve branch is performed, allowing a 2 cm long segment to be cut and removed. The proximal stump is then buried into an adjacent muscle belly and the surgical site is closed.

RESULTS

The technique is safe and reproducible in experienced hands.

CONCLUSION

This technique may be especially applicable in cases where neurologists need to study motor neuropathies. Contraindications of the technique include wrist instability and high median nerve palsies.

The multiple roles of nerve biopsy in the diagnosis and prognosis of suspected immune neuropathies

INTRODUCTION

The value of a sural nerve biopsy for the diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is controversial. Evidence-based recommendations for its implementation are lacking. We investigated factors leading to biopsy and analyzed biopsy outcomes and consequences, assessed the predictability of biopsy outcomes through clinical parameters to avoid unnecessary biopsies, and compared results with electrophysiological and clinical severity to determine their prognostic value.

METHODS

190 sural nerve biopsies were analyzed in two cohorts. One consisted of 163 biopsies and the second of 72 biopsies from the prospective Immune-mediated Neuropathies Biomaterial and Data registry (INHIBIT). Both have an intersection of 45 patients. 75 data sets from patients without biopsy were used. Analysis of nerve conduction studies, treatment, overall disability sum score (ODSS), biopsy outcomes, and diagnosis was performed.

RESULTS

51% of biopsied patients received the diagnosis CIDP (77% fulfilled EFNS/PNS criteria), 21% were not CIDP typical, and 27% were unspecific. Biopsied patients responded less frequently to immunotherapies at time of biopsy than non-biopsied patients (p = 0.003). Immunotherapy was initiated more frequently after biopsy (p < 0.001) and more often with intravenous immunoglobulins (p < 0.0001). 76% of all biopsied patients met the electrophysiological criteria for CIDP. Sensory nerve action potential amplitudes of 0 µV still provide 73% of histological diagnostic value. Histologic signs of degeneration predicted ODSS worsening after 1 year (p = 0.028) but disease severity did not correlate with histological damage severity.

DISCUSSION

The main indication for nerve biopsy was the treatment of refractory cases of autoimmune neuropathies with the therapeutic consequence of treatment initiation or escalation. Sural biopsy also provided prognostic information. Even with extinguished sural SNAP, the biopsy can still have diagnostic value.

Navigating diagnostic and therapeutic challenges in ocular manifestations of Hansen's disease and trachoma: A narrative review

Neglected tropical diseases (NTDs) encompass a group of approximately 20 diseases prevalent in tropical and subtropical regions, closely associated with poverty, affecting over a billion people in low-income countries. This manuscript aims to explore the ocular manifestations and burden of two significant NTDs, namely Hansen's disease and trachoma while addressing gaps in understanding and management. Hansen's disease, caused by Mycobacterium leprae , has a long history and presents with diverse neurological and ocular manifestations. Despite the availability of treatment, ocular complications persist, leading to significant visual impairment in some cases. The manuscript emphasizes the importance of early diagnosis, regular ophthalmic examinations, and follow-ups to prevent and control ocular complications, reducing the burden of visual impairment and blindness. Trachoma, caused by Chlamydia trachomatis , remains the leading infectious cause of blindness in underdeveloped and remote areas. The manuscript highlights the clinical diagnosis and implementation of the World Health Organization's (WHO's) SAFE (surgery, antibiotics, facial hygiene, and environmental sanitation) strategy to prevent transmission and associated blindness. However, challenges in health surveillance tools and underreporting of trachoma cases are addressed, emphasizing the need for improved strategies to combat the disease effectively. Through a comprehensive review of the ocular manifestations and management of Hansen's disease and trachoma, this manuscript contributes to the existing knowledge base and enhances a deeper understanding of these NTDs. Addressing gaps in understanding and management emphasizes the importance of implementing WHO's strategies and collaborative efforts to achieve the global goal of reducing the burden of NTDs and improving community health and well-being. The manuscript underscores the significance of early intervention, preventive measures, and technological advancements, providing valuable insights for policymakers, healthcare professionals, and researchers working in the field of NTDs.

Neurosurgical Intervention for Nerve and Muscle Biopsies

(1) Background: Neurologic and musculoskeletal diseases represent a considerable portion of the underlying etiologies responsible for the widely prevalent symptoms of pain, weakness, numbness, and paresthesia. Because of the subjective and often nonspecific nature of these symptoms, different diagnostic modalities have been explored and utilized. (2) Methods: Literature review. (3) Results: Nerve and muscle biopsy remains the gold standard for diagnosing many of the responsible neurological and musculoskeletal conditions. However, the need for invasive tissue sampling is diminishing as more investigations explore alternative diagnostic modalities. Because of this, it is important to explore the current role of neurosurgical intervention for nerve and muscle biopsies and its current relevance in the diagnostic landscape of neurological and musculoskeletal disorders. With consideration of the role of nerve and muscle biopsy, it is also important to explore innovations and emerging techniques for conducting these procedures. This review explores the indications and emerging techniques for neurological intervention for nerve and muscle biopsies. (4) Conclusions: The role of neurosurgical intervention for nerve and muscle biopsy remains relevant in diagnosing many neurological and musculoskeletal disorders. Biopsy is especially relevant as a supportive point of evidence for diagnosis in atypical cases. Additionally, emerging techniques have been explored to guide diagnostics and biopsy, conduct less invasive biopsies, and reduce risks of worsening neurologic function and other symptoms secondary to biopsy.

Re-Irradiation With Proton Beam Therapy for Localized Perineural Spread Following Presacral Recurrence in Sigmoid Colon Cancer: A Case Report

This report describes the effective management of localized perineural spread (PNS) to the sacral peripheral nerves following a presacral recurrence of colon cancer using proton beam therapy (PBT). The patient, a male in his 60s with a history of sigmoid colon cancer treated with laparoscopic Hartmann's procedure, presented with presacral recurrence two years post-surgery. Radical resection was deemed infeasible, leading to a combined treatment of PBT (75 Gy relative biological effectiveness (RBE) in 25 fractions) and capecitabine. However, three years post-PBT, magnetic resonance imaging revealed swelling of the left S2 nerve with abnormal fluorodeoxyglucose uptake, indicating localized PNS. Re-irradiation with PBT (75 Gy RBE in 25 fractions) was conducted, carefully considering the overlap with the previous PBT field and aiming to minimize dosage to adjacent organs. At 1.5 years post-reirradiation, the patient remained free of recurrence. This case underscores the potential efficacy of PBT and emphasizes the need for further research to assess its broader applicability in comparable situations.

IFNγ protects motor neurons from oxidative stress via enhanced global protein synthesis in FUS-associated amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis type 6 (ALS6) is a familial subtype of ALS linked to Fused in Sarcoma (FUS) gene mutation. FUS mutations lead to decreased global protein synthesis, but the mechanism that drives this has not been established. Here, we used ALS6 patient-derived induced pluripotent stem cells (hIPSCs) to study the effect of the ALS6 FUSR521H mutation on the translation machinery in motor neurons (MNs). We find, in agreement with findings of others, that protein synthesis is decreased in FUSR521H MNs. Furthermore, FUSR521H MNs are more sensitive to oxidative stress and display reduced expression of TGF-β and mTORC gene pathways when stressed. Finally, we show that IFNγ treatment reduces apoptosis of FUSR521H MNs exposed to oxidative stress and partially restores the translation rates in FUSR521H MNs. Overall, these findings suggest that a functional IFNγ response is important for FUS-mediated protein synthesis, possibly by FUS nuclear translocation in ALS6.

Utilising clinical parameters to improve the selection of nerve biopsy candidates

BACKGROUND

Peripheral nerve biopsy is a valuable final diagnostic tool; however, histopathological results can be non-diagnostic.

AIMS

We aim to identify quality improvement measures by evaluating the pre-biopsy assessment and diagnostic yield of specific histopathological diagnosis.

METHODS

This was a retrospective study based on 10 years of experience with peripheral nerve biopsies at a single centre. Clinical data were obtained regarding pre-biopsy history, examination, serum and cerebrospinal fluid (CSF) investigations, neurophysiology and peripheral nerve imaging. Based upon a histopathological outcome, patients were grouped into vasculitis, granulomatous and infiltrative (diagnostic) group, or a comparison group of non-specific axonal neuropathy and normal (non-specific/normal) group.

RESULTS

From a cohort of 64 patients, 21 (32.8%) were included in the diagnostic group and 30 (46.9%) in the non-specific/normal group. Clinical parameters associated with the diagnostic group were shorter history (mean 10.2 months vs 38.1), stepwise progression (81% vs 20%), neuropathic pain (85.7% vs 56.7%), vasculitic rash (23.8% vs 0%), mononeuritis multiplex (57.1% vs 10%), asymmetry (90.5% vs 60%), raised white cell count (47.6% vs 16.7%), myeloperoxidase antibody (19.1% vs 0%) and abnormal peripheral nerve imaging (33.3% vs 10%).

CONCLUSION

Selection of patients undergoing nerve biopsy requires careful consideration of clinical parameters, including peripheral nerve imaging. Several quality improvement measures are proposed to improve yield of clinically actionable information from nerve biopsy.

What is the Next Step after an Electrodiagnostic Study in Children with Polyneuropathies? Rationale for Laboratory and Other Diagnostic Tests

The etiology of polyneuropathies varies in the pediatric population, where hereditary or metabolic disorders are far more common than in adults. However, treatable polyneuropathies, also prevalent in these settings, are those to prioritize. Moreover, diagnosing subacute and chronic symptoms in children can be challenging compared to adults. Therefore, selecting the best and most relevant laboratory investigations and paraclinical studies is critical. This taskcan be relatively challenging in countries with limited resources or insurance coverage. This study describe the various types of polyneuropathies found in children and their characteristics and suggest an algorithm for using the best laboratory tests in the context of the Iranian healthcare system.

Localization and Diagnostic Evaluation of Peripheral Nerve Disorders

OBJECTIVE

This article provides a framework for the initial evaluation of patients with suspected peripheral nerve disease. The key clinical elements of peripheral nerve diseases can help the practicing neurologist differentiate among peripheral neuropathies with similar presentations.

LATEST DEVELOPMENTS

The wide range of peripheral nerve diseases with similar clinical presentations can pose a diagnostic challenge. The large array of available testing modalities (including imaging and electrodiagnostic, autonomic, laboratory, biopsy, and genetic testing) further complicates clinical decision making. Recent developments (eg, discovery of new autoantibodies, genetic variations, and histopathologic techniques) across the peripheral neuropathy spectrum have resulted in an increased need to evaluate patients logically and with a tailored diagnostic approach.

ESSENTIAL POINTS

A careful approach that focuses on key clinical elements combined with an understanding of purposeful diagnostic testing can lead to a successful diagnosis of peripheral nerve diseases.

Investigation and Management of Immunoglobulin M- and Waldenström-Associated Peripheral Neuropathies

The immunoglobulin M (IgM)-associated peripheral neuropathies (PN) are a heterogeneous group of disorders representing most paraproteinemic neuropathy cases. They are associated with IgM monoclonal gammopathy of undetermined significance (MGUS) or Waldenström macroglobulinemia. Establishing a causal link between a paraprotein and neuropathy can be challenging but is necessary to adopt an appropriate therapeutic approach. The most common type of IgM-PN is Antimyelin-Associated-Glycoprotein neuropathy, but half of the cases are of other causes. Progressive functional impairment is an indication for treatment, even when the underlying disorder is IgM MGUS, involving either rituximab monotherapy or combination chemotherapy to achieve clinical stabilization.

Central and Peripheral Nervous System Complications of Vasculitis Syndromes from Pathology to Bedside: Part 2-Peripheral Nervous System

PURPOSE OF REVIEW

Peripheral nervous system vasculitides (PNSV) are a heterogeneous group of disorders with a clinical subset that may differ in prognosis and therapy. We provide a comprehensive update on the clinical assessment, diagnosis, complications, treatment, and follow-up of PNSV.

RECENT FINDINGS

Progress in neuroimaging, molecular testing, and peripheral nerve biopsy has improved clinical assessment and decision-making of PNSV, also providing novel insights on how to prevent misdiagnosis and increase diagnostic certainty. Advances in imaging techniques, allowing to clearly display the vessel walls, have also enhanced the possibility to differentiate inflammatory from non-inflammatory vascular lesions, while recent histopathology data have identified the main morphological criteria for more accurate diagnosis and differential diagnoses. Overall, the identification of peculiar morphological findings tends to improve diagnostic accuracy by defining a clearer boundary between systemic and non-systemic neuropathies. Therefore, the definition of epineurium vessel wall damage, type of vascular lesion, characterization of lymphocyte populations, antibodies, and inflammatory factors, as well as the identification of direct nerve damage or degeneration, are the common goals for pathologists and clinicians, who will both benefit for data integration and findings translation. Nevertheless, to date, treatment is still largely empiric and, in some cases, unsatisfactory, thus often precluding precise prognostic prediction. In this context, new diagnostic techniques and multidisciplinary management will be essential in the proper diagnosis and prompt management of PNSV, as highlighted in the present review. Thirty to fifty percent of all patients with vasculitis have signs of polyneuropathy. Neuropathies associated with systemic vasculitis are best managed according to the guidelines of the underlying disease because appropriate workup and initiation of treatment can reduce morbidity. Steroids, or in severe or progressive cases, cyclophosphamide pulse therapy is the standard therapy in non-systemic vasculitic neuropathies. Some patients need long-term immunosuppression. The use of novel technologies for high-throughput genotyping will permit to determine the genetic influence of related phenotypes in patients with PNSV.

[Nerve biopsy in the diagnosis of peripheral neuropathies]

The indications for nerve biopsy have diminished in recent years. This examination nevertheless remains essential in certain cases of peripheral neuropathies, making it possible to specify the diagnosis or the mechanism of injury for a therapeutic purpose. It is a simple but "invasive" procedure, which can only be performed once on the same nerve. The indications are thus discussed on a case-by-case basis and based on a range of clinical, electrophysiological, biological or even genetic arguments. This involves close collaboration between clinical physicians and pathologists. The main difficulty of this biopsy concerns the fragility of the sample and the techniques necessary for its interpretation, requiring it to be carried out in expert centers. Nerve biopsy is closely related to skin biopsy in the search for small fiber neuropathy. It is a particular technique, but very well codified. The purpose of this review is to recall the indications and contraindications of nerve biopsy, and to explain what the contributions are but also the limits of this examination as well as of skin biopsy.

Neuromuscular pathology

In this chapter, we discuss the indications for muscle, nerve, and skin biopsies, the techniques and normal processing of biopsy specimens, normal histological appearance, and the commonest histopathological abnormalities of different myopathies and neuropathies.

Central nervous system, spinal root ganglion and brachial plexus involvement in leprosy: A prospective study

Background

Leprosy is primarily a disease of peripheral nerves. Some isolated case reports and case series have communicated imaging changes in the central nervous system (CNS) and brachial plexus in patients with leprosy.

Objectives

To study the neuroimaging abnormalities in patients with lepra bacilli-positive neuropathy in the context of CNS, spinal root ganglion, and brachial plexus.

Design

Prospective observational study

Methods

We screened newly-diagnosed patients with multibacillary leprosy presenting with neuropathy. Patients with bacilli-positive sural nerve biopsies were included in the study and subjected to magnetic resonance imaging (MRI) of the brain and spinal cord.

Results

A total of 54 patients with bacteriologically confirmed multibacillary leprosy were screened; Mycobacterium leprae was demonstrated in the sural nerve biopsies of 29 patients. Five patients (5/29; 17.24%) had MRI abnormalities in CNS, spinal root ganglion, and/or brachial plexus. Three patients had MRI changes suggestive of either myelitis or ganglionitis. One patient had T2/FLAIR hyperintensity in the middle cerebellar peduncle while 1 had T2/FLAIR hyperintensity in the brachial plexus.

Conclusion

CNS, spinal root ganglion, and brachial plexus are involved in patients with leprous neuropathy. Immunological reaction against M leprae antigen might be a plausible pathogenetic mechanism for brachial plexus and CNS imaging abnormalities.

A case of left foot drop as initial symptom of granulomatosis with polyangiitis: Triggered by COVID-19 disease?

In Granulomatosis with polyangiitis (GPA), involvement of the peripheral nervous system is frequent but its occurrence as an initial presentation is unusual. This case highlights the importance of this occurrence to permit an early diagnosis. Moreover, GPA started after a coronavirus disease 2019 infection and could have been induced by this.

The physicians should recognize peripheral neuropathy as one of the first presentations of GPA, even if it’s rare, in order to permit an early diagnosis. Moreover, this case complements previously reported cases of COVID‐19‐induced auto‐immune disease.

Skin Biopsy as a Novel Diagnostic Aid in Immune-Mediated Neuropathies

Immune-mediated neuropathies are a heterogenous group of inflammatory peripheral nerve disorders. They can be classified according to the domain where the autoimmune process begins: the internode, paranode, or node. However, conventional diagnostic tools, electrodiagnosis (EDX), and autoantibody testing do not fully address this issue. In this institutional cohort study, we investigated the value of dermal myelinated fiber analysis for target domain-based classification. Twenty-seven consecutive patients with immune-mediated neuropathies underwent skin biopsies. The sections were stained with antibodies representative of myelinated fiber domains and were scanned using a confocal microscope. Clinical and pathological features of each patient were reviewed comprehensively. Quantitative morphometric parameters were subjected to clustering analysis, which stratified patients into 3 groups. Cluster 1 ("internodopathy") was characterized by prominent internodal disruption, intact nodes and paranodes, demyelinating EDX pattern, and absence of nodal-paranodal antibodies. Cluster 2 ("paranodopathy") was characterized by paranodal disruption and corresponding antibodies. Morphological changes were restricted to the nodes in cluster 3; we designated this cluster as "nodopathy." This report highlights the utility of skin biopsy as a diagnostic aid to gain pathogenic insight and classify patients with immune-mediated neuropathies.

Pragmatic guide to peripheral nerve disease and the role of clinical biomarkers

In clinical neurology practice, there are few sensitive, specific and responsive serological biomarkers reflecting pathological processes affecting the peripheral nervous system. Instead, we rely on surrogate multimodality biomarkers for diagnosis and management. Correct use and interpretation of the available tests is essential to ensure that appropriate treatments are used and adjusted in a timely fashion. The incorrect application or interpretation of biomarkers can result in misdiagnosis and delays in appropriate treatment. Here, we discuss the uses and limitations of such biomarkers and discuss possible future developments.

Relevance of Nerve Biopsy in the Diagnosis of Chronic Inflammatory Demyelinating Polyneuropathy—A Systematic Review

Chronic Inflammatory Demyelinating Polyneuropathy is an immune-mediated pathology of the peripheral nerves and nerve roots that leads to weakness and sensory symptoms. Given its clinical heterogeneity, often times diagnosis is challenging. Even though nerve conduction studies and clinical features are the main criteria used for diagnosis, supplementary investigations, such as nerve biopsies, cerebral spinal fluid examination and magnetic resonance studies, may be used in order to confirm the diagnosis. Given the fact that the hallmark in CIDP physiopathology is the demyelination process, nerve biopsies are used to demonstrate and assess the magnitude of the phenomenon. The question and the main interest of this review is whether histopathological findings are relevant for the diagnosis and can be useful in disease assessment.

Early Detection of Diabetic Peripheral Neuropathy by fMRI: An Evidence-Based Review

With the significant rise in the prevalence of diabetes worldwide, diabetic peripheral neuropathy (DPN) remains the most common complication among type 1 and 2 diabetics. The adverse sequelae of DPN, which include neuropathic pain, diabetic foot ulcers and lower-limb amputations, significantly impact quality of life and are major contributors to the biopsychosocial and economic burden of diabetes at the individual, societal and health system levels. Because DPN is often diagnosed in the late stages of disease progression by electromyography (EMG), and neuropathic pain as a result of DPN is difficult to treat, the need for earlier detection is crucial to better ascertain and manage the condition. Among the various modalities available to aid in the early detection of DPN, functional magnetic resonance imaging (fMRI) has emerged as a practical tool in DPN imaging due to its noninvasive radiation-free nature and its ability to relate real-time functional changes reflecting the local oxygen consumption of regions of the CNS due to external stimuli. This review aims to summarize the current body of knowledge regarding the utility of fMRI in detecting DPN by observing central nervous system (CNS) activity changes among individuals with DPN when compared to controls. The evidence to date points toward a tendency for increased activity in various central neuroanatomical structures that can be detected by fMRI and positively correlates with diabetic neuropathic pain.

Follow-up assessment of patients with Pure Neural Leprosy in a reference center in Rio de Janeiro—Brazil

Introduction

Pure Neural Leprosy (PNL) is a rare clinical form of leprosy in which patients do not present with the classical skin lesions but have a high burden of the disability associated with the disease. Clinical characteristics and follow up of patients in PNL are still poorly described in the literature.

Objective

This paper aims to describe the clinical, electrophysiological and histopathological characteristics of PNL patients, as well as their evolution after multidrug therapy (MDT).

Methods

Fifty-two PNL patients were selected. Clinical, nerve conduction studies (NCS), histopathological and anti-PGL-1serology were evaluated. Patients were also assessed monthly during the MDT. At the end of the MDT, all of the patients had a new neurological examination and 44 were submitted to another NCS.

Results

Paresthesia was the complaint most frequently reported by patients, and in the neurological examination the most common pattern observed was impairment in sensory and motor examination and a mononeuropathy multiplex. Painful nerve enlargement, a classical symptom of leprosy neuropathy, was observed in a minority of patients and in the motor NCS axonal injuries, alone or in combination with demyelinating features, were the most commonly observed. 88% of the patients did not present any leprosy reaction during MDT. There was no statistically significant difference between the neurological examinations, nor the NCS pattern, performed before and after the MDT.

Discussion

The classical hallmarks of leprosy neuropathy are not always present in PNL making the diagnosis even more challenging. Nerve biopsy is an important tool for PNL diagnosis as it may guide therapeutic decisions. This paper highlights unique characteristics of PNL in the spectrum of leprosy in an attempt to facilitate the diagnosis and management of these patients.

Neuropathy is responsible for most of the disability associated with leprosy disease. The pure neural leprosy (PNL), in spite of being a rare clinical presentation of that, has some singular characteristics that are still poorly studied. In this study, we selected 52 patients at the diagnosis to describe their clinical, neurophysiological and histopathological presentation patterns as well as their evolution during the multidrug therapy (MDT). We confirmed that sensitive symptoms were the most commonly described by PNL patients but neural pain is rare. Also confirmed that mononeuropathy mutiplex was the most common pattern observed at neurological examination and at the nerve conduction studies at the moment of the diagnosis. However we showed that painful nerve enlargement other cardinal signs of leprosy, besides the skin lesions, is not common in this group of patients, There was no statistically significant difference between the neurological examination and NCS performed before and after the MDT.During the MDT88.4% of the patients did not have any leprosy reaction. This may suggest that that MDT was effective in stopping disease progression. Our results highlight the difficulties in the diagnosis of PNL and the progression following MDT in an attempt to prevent further disability in PNL patients.

Clinical and Radiological Features of Intramuscular Orbital Amyloidosis: A Case Series and Literature Review

PURPOSE

Orbital amyloidosis of the extraocular muscles (EOMs) is a rare condition, and its clinicoradiological features are not well elucidated. This study describes the characteristic clinical signs, MRI features, and potential treatment options.

METHODS

Retrospective multicenter case series and literature review of EOM amyloidosis.

RESULTS

Five cases were identified for inclusion. Common clinical findings were diplopia, ophthalmoplegia, and proptosis. Systemic amyloidosis was more likely to present with multiple muscle involvement, but no particular pattern was observed with localized disease. On MRI, amyloid deposition was characterized as a heterogeneous intramuscular mass with T2 hypointensity and post contrast enhancement. Management is dependent on the extent of disease and functional impairment; options include surgical debulking and radiation therapy.

CONCLUSION

EOM amyloidosis is uncommon. The combination of clinical and radiologic findings described in this study should lead to its clinical suspicion.

Translating morphology from bench side to bed side via neurophysiology: 8-min protocol for peripheral neuropathy research

BACKGROUND

Peripheral neuropathy treatment is not always satisfactory. To fill this gap, inferences from bench side are warranted, where morphological and pathogenetic determinations can be performed. Nerve conduction studies (NCS) are ideal to translate results from preclinical to clinical setting.

NEW METHODS

We propose a comprehensive 8-minute protocol for sensory-motor neurophysiological assessment, similar to routine clinical practice: sensory proximal and distal caudal nerves, motor caudal nerve, and sensory digital nerve recordings were used and tested in 2 different experimental settings. In Experiment 1 we compared control (CTRL) animals to a severe sensory-motor polyneuropathy (animals treated with vincristine [VCR]), and in Experiment 2 CTRL animals were compared to a mild sensory polyneuropathy (animals treated with oxaliplatin [OHP]). NCS were performed after 1-month of chemotherapy and matched with confirmatory neuropathological analyses.

RESULTS

VCR treated animals showed, at NCS, a relevant sensory-motor polyneuropathy ensued at the end of treatment; whereas, OHP animals showed a mild distal sensory neuropathy. These patterns were confirmed by neuropathological analysis.

COMPARISON WITH EXISTING METHODS

In literature, the majority of proposed neurophysiological protocols relies mainly on a single nerve testing, rather than a combination of them, and only a few studies tested both caudal and sciatic nerve branches, nevertheless not aiming at fully reproduce clinical protocols (e.g., seeking for length-dependency); to provide evidence of appropriateness of our protocol we applied a gold standard: neuropathology.

CONCLUSION

The simple and rapid protocol here presented can be suggested as a good translation outcome measure in preclinical setting.

Nerve biopsy: Current indications and decision tools

After initial investigation of patients presenting with symptoms suggestive of neuropathy, a clinical decision is made for a minority of patients to undergo further assessment with nerve biopsy. Many nerve biopsies do not demonstrate a definitive pathological diagnosis and there is considerable cost and morbidity associated with the procedure. This highlights the need for appropriate selection of patients, nerves and neuropathology techniques. Additionally, concomitant muscle and skin biopsies may improve the diagnostic yield in some cases. Several advances have been made in diagnostics in recent years, particularly in genomics. The indications for nerve biopsy have consequently changed over time. This review explores the current indications for nerve biopsies and some of the issues surrounding its use. Also included are comments on alternative diagnostic modalities that may help to supplant or reduce the use of nerve biopsy as a diagnostic test. These primarily include extraneural biopsy and neuroimaging techniques such as magnetic resonance neurography and nerve ultrasound. Finally, we propose an algorithm to assist in deciding when to perform nerve biopsies.