A case of superior trunk brachial plexus injury after right mini-thoracotomy mitral valve repair.

We report a case of superior trunk brachial plexus injury following a right mini-thoracotomy mitral valve repair. A 45-year-old woman with systemic lupus erythematosus, who was on steroids and immunosuppressive drugs, underwent mitral valve repair via right mini-thoracotomy. The patient was positioned in the left semisagital position with the right upper arm elevated. Postoperatively, she exhibited focal motor and sensory deficits in the right upper extremity, and a superior trunk brachial plexus injury (BPI) on the right side was diagnosed through brachial plexus MRI and electrophysiological examination. The nerve injury was likely due to excessive left lateral flexion of the head during the procedure. Sensation returned to normal 4 weeks postoperatively, and muscle strength fully recovered 3 months postoperatively. Careful attention to positioning during minimally invasive cardiac surgery is crucial to prevent nerve compression in superficial areas and excessive lateral flexion of the head.