Surgical repositioning of misplaced subthalamic electrodes in Parkinson's disease: location of effective and ineffective leads.

There is no clear consensus regarding the optimal location for placing deep brain stimulation (DBS) electrodes within the subthalamic nucleus (STN) target region in Parkinson's disease. In cases of poor symptom control or adverse effects following lead placement, leads presumed to be inadequately positioned may be corrected by surgical revision. We retrospectively analyzed a series of 8 patients who underwent surgical lead revision, to study the anatomic boundaries of effective lead placement. Reoperation to achieve changes of 2-5 mm in DBS lead position targeting the dorsolateral part of the STN produced significant clinical improvement in these patients. Improvements were due to better symptom control, reduction of stimulation-induced adverse effects or both. In many cases, leads in a peripheral zone of the STN were repositioned to a more central location within the sensorimotor territory of the nucleus. These results are contrasted with findings in other studies demonstrating optimal lead placement in STN border zones or neighboring white-matter tracts. Copyright 2009 S. Karger AG, Basel.