Spinal accessory neuropathy after deep brain stimulation for Parkinson's disease.

We report a man with Parkinson's disease who developed right spinal accessory neuropathy after right subthalamic nucleus deep brain stimulator and infraclavicular pulse generator implantation. He complained of right shoulder pain and weakness in the post-operative period. He was subsequently diagnosed with a right spinal accessory nerve injury, confirmed by neuromuscular electrodiagnostic studies - electromyography (EMG) and nerve conduction (NC) -, possibly caused by a stretch injury to the nerve at the time of creation of the subcutaneous tunnel for placement of the extension lead of the deep brain stimulator system. However, he had near complete clinical resolution of the spinal accessory neuropathy within nine months after surgery. As a result of this complication, we now map the spinal accessory nerve electrophysiologically during deep brain stimulation surgery.