Persistent abnormal shoulder elevation after accessory nerve injury and differential diagnosis with post-traumatic focal shoulder-elevation dystonia: report of a case and literature review.

We report on a patient with persistent abnormal shoulder posture associated with isolated neurogenic hypertrophy of the trapezius muscle due to accessory nerve injury. The patient complained of marked difficulty in shoulder elevation and abduction. Over 6-month treatment with botulinum toxin, there was a complete resolution.