Diagnosis of Hourglass-Like Constriction Neuropathy of the Radial Nerve Using High-Resolution Magnetic Resonance Neurography: A Report of Two Cases.

Du Hwan Kim,Min Cheol Chang,Duk Hyun Sung

doi:10.3390/diagnostics10040232

Abstract

Hourglass-like constriction neuropathy is a neurological condition caused by fascicular constriction of one or more peripheral nerves, unrelated to intrinsic or extrinsic compression. It is often neglected in clinical practice, and its diagnosis is challenging. Here, we report two cases of hourglass-like constriction neuropathy in the radial nerve diagnosed using high-resolution magnetic resonance neurography (MRN). Two men, aged 47 and 19 years, developed sudden weakness in the left wrist and finger extensors. They were diagnosed with radial neuropathy between the left mid-humerus level and the elbow joint, using the electrodiagnostic test. To evaluate the cause of the nerve lesion and the lesion location, high-resolution MRN was performed. Patient 1 showed an hourglass-like constriction of the left posterior interosseous nerve within the epineurium of the left radial nerve, 8.9 cm proximal to the lateral epicondyle. Patient 2 showed two focal constrictions of the left radial nerve, 8.0 and 6.9 cm proximal to the lateral epicondyle, respectively, and distal to the radial groove. Additionally, bull’s eye signs were observed juxta-proximal to constrictions of the left radial nerve. The findings were indicative of hourglass-like constriction neuropathy. Both of the patients underwent surgery. However, at the 6-month follow-up, their motor weakness showed no improvement. MRN can be beneficial for diagnosing hourglass-like constriction neuropathy and locating the lesion.

Highlights

Hourglass-like constriction neuropathy is a neurological condition caused by fascicular constriction of one or more peripheral nerves, unrelated to intrinsic or extrinsic compression or trauma [1,2,3].Hourglass-like constriction neuropathy can manifest as sudden neurological symptoms, such as paralysis, sensory deficit and neuropathic pain [1,2,3]
The accurate diagnosis of hourglass-like constriction neuropathy is challenging, as it is not observed in conventional magnetic resonance imaging (MRI) and is usually detected during exploratory surgery [1]
Representative non-compressive causes include idiopathic neuralgic amyotrophy and hourglass-like constriction neuropathy can manifest as symptoms similar to those of idiopathic neuralgic is severe constriction neuropathy [1]

Summary

Introduction

Hourglass-like constriction neuropathy is a neurological condition caused by fascicular constriction of one or more peripheral nerves, unrelated to intrinsic or extrinsic compression or trauma [1,2,3].Hourglass-like constriction neuropathy can manifest as sudden neurological symptoms, such as paralysis, sensory deficit and neuropathic pain [1,2,3]. Hourglass-like constriction neuropathy is a neurological condition caused by fascicular constriction of one or more peripheral nerves, unrelated to intrinsic or extrinsic compression or trauma [1,2,3]. No treatment protocol for hourglass-like constriction neuropathy has been established, but surgery has proven beneficial [3]. The accurate diagnosis of hourglass-like constriction neuropathy is challenging, as it is not observed in conventional magnetic resonance imaging (MRI) and is usually detected during exploratory surgery [1]. The bull’s eye sign is a specific finding of hourglass-like constriction neuropathy [6]. It refers to Diagnostics 2020, 10, 232; doi:10.3390/diagnostics10040232 www.mdpi.com/journal/diagnostics

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Discussion

Conclusion