Postmortem analysis of bilateral subthalamic electrode implants in Parkinson's disease.

This is the second neuropathological report detailing bilateral electrodes targeting the subthalamic nucleus (STN) in idiopathic Parkinson's disease (PD). The patient presented with unilateral tremor-dominant parkinsonism. Bilateral STN stimulation was carried out 7 years later due to significant disease progression and severe motor fluctuations. The patient exhibited bilateral improvements in rigidity and bradykinesia both intraoperatively and postoperatively. The patient died 2 months later from aspiration pneumonia. Neuropathological examination confirmed both the diagnosis of PD and the electrode placements. The tip of the left electrode was located medially and posteriorly in the left STN and the tip of the right electrode entered the base of the thalamus/zona incerta immediately above the right STN. Tissue changes associated with the subthalamic electrode tracts included mild cell loss, astrogliosis, and some tissue vacuolation. Our postmortem analysis indicates little tissue damage associated with STN stimulation for PD.