Surgical targeting accuracy analysis of six methods for subthalamic nucleus deep brain stimulation

A commonly adopted surgical target in deep brain stimulation (DBS) procedures, the subthalamic nucleus (STN) is located deep within the brain and is surrounded by delicate deep-brain structures. Symptoms of Parkinson's disease can be reduced by precisely implanting a multi-electrode stimulator at a specific location within the STN and delivering the appropriate signal to the target. A number of techniques have recently been proposed to facilitate STN DBS surgical targeting and thereby improve the surgical outcome. This paper presents a retrospective study evaluating the target localization accuracy and precision of six approaches in 55 STN DBS procedures. The targeting procedures were performed using a neurosurgical visualization and navigation system, which integrates normalized and standardized anatomical and functional information into the planning environment. In this study, we employed as the "gold standard" the actual surgical target locations determined by an experienced neurosurgeon using both pre-operative image-guided surgical target/trajectory planning and intra-operative electrophysiological exploration and confirmation. The surgical target locations determined using each of the six targeting methods were compared with the "gold standards". The average displacement between the actual surgical targets and those planned with targeting approaches was 3.0 +/- 1.3 mm, 3.0 +/- 1.3 mm, 3.0 +/- 1.0 mm, 2.6 +/- 1.1 mm, 2.5 +/- 0.9 mm, and 1.7 +/- 0.7 mm for approaches based on T2-weighted MRI, a brain atlas, T1 and T2 maps, an electrophysiological database, a collection of final surgical targets from previous patients, and the combination of these functional and anatomical data, respectively. The technique incorporating both anatomical and functional data provides the most reliable and accurate target position for STN DBS.