Long-term hardware-related complications of deep brain stimulation

OBJECTIVE: To determine the incidence of long-term hardware-related complications of deep brain stimulation (DBS). METHODS: The study design is a retrospective chart review of a single-surgeon, single-institution experience with DBS in 84 consecutive cases from 1993 to 1999. Only patients with a minimum follow-up of I year were considered. Five patients were excluded because trial stimulation failed to achieve pain relief (n = 4) or because the procedure was aborted owing to hemorrhage (n = 1). Seventy-nine patients received 124 permanent DBS electrode implants. RESULTS: The mean follow-up period was 33 months, and the cumulative follow-up time was 217 patient-years or 310 electrode-years. Overall, 20 patients (25.3%) had 26 hardware-related complications involving 23 (18.5%) of the electrodes. There were 4 lead fractures, 4 lead migrations, 3 short or open circuits, 12 erosions and/or infections, 2 foreign body reactions, and one cerebrospinal fluid leak. The hardware-related complication rate per electrode-year was 8.4%. The most common complications were related to the electrode connectors. A significant finding was a high number of complications involving erosions or infections, which occurred in 7 of 12 instances as a late complication (beyond 12 mo). CONCLUSION: Long-term follow-up reveals that hardware-related complications occur in a significant number of patients. Factors that lead to such complications must be identified and addressed to maximize the important benefits of DBS therapy.