Neuralgic Amyotrophy: Clinical and Epidemiological Features From a Spine Neurosurgeon's Perspective

Abstract

Abstract INTRODUCTION Neuralgic amyotrophy (NA) is a rare but serious condition characterized by the acute onset of shoulder and arm pain, weakness, and sensory loss. NA may therefore be misdiagnosed as a cervical spine disease, or as a shoulder disorder. With little literature on the behavior of NA from a spine surgeon's perspective, accurate diagnosis and subsequent counseling of patients with NA can be challenging. METHODS Data were collected from 30 patients during an 11-yr period. Neurophysiologic studies were performed in all patients. A total of 19 patients were evaluated by magnetic resonance neurography (MRN) using a 1.5-T or 3.0-T scanner. RESULTS A total of 30 patients were diagnosed with NA based on positive neurophysiologic findings. The most common clinical presentation was severe shoulder pain and weakness in 22 patients (73%). A total of 15 patients (50%) were misdiagnosed with cervical disc herniations (12 patients), a pancoast syndrome (1 patient), a cubital tunnel syndrome (1 patient), and a posterior interosseous syndrome (1 patient). In neurophysiologic studies, the most commonly involved trunk of the brachial plexus was the upper trunk in 24 patients. MRN was taken at the acute phase in all patients and showed a thickened and hyperintense trunk of the affected brachial plexus, consistent with plexitis. The prognosis was good with a functional recovery (of up to 80%) in 28 patients (93%) at final follow-up period. Among them, however, 6 patients still had mild weakness (Grade IV). Two patients did not achieve their functional motor recovery (Grade 3) at 18 mo after onset. CONCLUSION Because NA is misdiagnosed in many cases, awareness and accurate diagnosis of this disorder can help neurosurgeons determine the most appropriate treatment. To prevent unnecessary surgical procedures or studies, it is important to distinguish NA from other alternative diseases. Neurophysiologic studies are critical for diagnosis of NA, and MRN is very helpful for early diagnosis.