Introduction: Therapeutic effectiveness of deep brain stimulation depends on the precise placement of the electrode with suboptimal performance of increased side affects assocaited with poor lead placement. A potential and rare source of suboptimal lead placement presents from deformation of DBS electrodes themselves.
Methods: Routine to our practice is the careful inspection of DBS electrode prior to implant. Any irregularities noted were generally very trivial, primarily blebs of insulating material at the tip of the electrode slightly off axis to the electrode. Rarely subtle deformity in alignment of the electrode tip led to the appearence of a slightly "bent" electrode (fig. 1). In approximately 1100 electrode implants only 15 leads were not implanted were not implanted as a result of concerns about the lead irregulaties and only two implanted electrodes were replaced at the time of surgery secondary to concerns about alignment.
Results: During routine implant of a DBS lead, intraoperative flouroscopy demonstrated deflection of the electrode judged significant enough to require replacement of the electrode (fig. 2). Close attention to DBS electrodes before implant revealed several leads with a subtle deformation. Evaluation of one of the deformed leads in a simple gel revealed increased prominence of the deflection from target with removal of the indtroducing style (fig 3).
Conclusions: In over 1100 DBS electrode implants only two implanted had a deflection felt intrinsic to the electrode significant enough to justify replacement. Though exceedingly rare, it would appear prudent to carefully scrutinize electrodes for deformity prior to implant.
Patient Care: Awareness of and identification of DBS lead deformation prior to implant can prevent suboptimal lead placement and subsequent necessity for revision.
Learning Objectives: 1. Encourage close examination of the DBS electrode for any deformity prior to implant. 2. Note the possibility of lead deformation prior to implant.