Diagnosis of unilateral trapezius muscle palsy: 54 Cases.

INTRODUCTION: We assessed medical and surgical causes of unilateral trapezius muscle (TM) palsy and/or wasting. METHODS: Clinical and electrodiagnostic data were collected in 54 patients with TM impairment over 21 years. RESULTS: In total, 35 cases had a medical origin: neuralgic amyotrophy (NA, n = 22), idiopathic unilateral TM palsy (n = 5), regional neck radiotherapy for different conditions (n = 2), facioscapulohumeral dystrophy (FSH) (n = 4), abnormal loop of the jugular vein (n = 1), or basilar impression (n = 1). Other etiologies were neck surgery (n = 16), cervicofacial lift (n = 2), or trauma (n = 1). CONCLUSIONS: There were 5 main diagnostic findings in unilateral TM palsy: (1) dynamic examination of the scapula provides a new clinical sign; (2) NA is the most frequent medical cause; (3) in medical cases, partial preservation of the upper TM can offer good recovery; (4) FSH must be considered, especially in young patients; and (5) minor neck surgery can lead to severe TM palsy. Muscle Nerve 56: 215-223, 2017.