Bowstringing as a Complication of Deep Brain Stimulation: Case Report

OBJECTIVE: This retrospective case series describes bowstringing as a complication of deep brain stimulator implantation for Parkinson's disease, defined as abnormal tethering of leads between the pulse generator and stimulating electrode, associated with contracture of the patient's neck over the extension cable. There are no previous reports of this specific complication, which presumably has been more broadly classified under hardware-related complications. CLINICAL PRESENTATION: Bowstringing may result in discomfort, restriction of movements, and/or equipment malfunction. Patients were identified by postoperative surveillance in clinic and by review of our database of Parkinson's disease patients who had undergone subthalamic nucleus deep brain stimulator placement. The incidence of this complication was 2.6% (6/228) in our overall clinic population, composed of 0% (0/181) of patients who received a Soletra pulse generator and 12.7% (6/47) of patients who received a Kinetra pulse generator. INTERVENTION: The proportion of patients with bowstringing requiring operative revision was 83% (5/6), with 60% (3/5) patients undergoing conversion to single-channel pulse generators and 40% (2/5) undergoing revision of the original dual-channel pulse generator. CONCLUSION: Factors associated with bowstringing include the use of dual-channel pulse generators and scar lysis complicated by seroma or infection. The mean time from implantation to bowstringing was 8.6 months with a range of 0.5 to 22 months. Bowstringing is a rare but potentially serious complication, and further study is needed to accurately predict and avoid this problem.