Comparison of the Stereotactic Accuracies of Function-Guided Deep Brain Stimulation, Calculated Using Multitrack Target Locations Geometrically Inferred from Three-Dimensional Trajectory Rotations, and of Magnetic Resonance Imaging-Guided Deep Brain Stimulation and Outcomes.

OBJECTIVE: In previous studies, multitrack trajectories in deep brain stimulation (DBS) have usually been approximated. Using a geometrically more accurate method, we compared the stereotactic accuracy of DBS with multitrack microelectrode recording and awake stimulation (function group) and MRI-guided DBS (MRI group).

METHODS: One hundred and seventy-two leads used in DBS between April 2014 and January 2016 were evaluated for stereotactic errors. Targets were the subthalamic nucleus (STN, 139 leads) or globus pallidus interna (GPi, 33 leads). We geometrically calculated shifted-track targets by considering the three-dimensional stereotactic ring and arc rotations. Stereotactic errors were calculated using Euclidean distances perpendicular to trajectories. Motor outcomes according to the Unified Parkinson's Disease Rating Scale (UPDRS) part III, improvement percentages by stimulations, were analyzed in 24 patients with 1 year follow-ups.

RESULTS: Functional evaluation tended to increase stereotactic errors in the STN function group (n = 129; 1.4 ± 0.7 mm) more than in the STN MRI group (n = 10; 1.0 ± 0.6 mm; P = 0.06). Leads with higher stereotactic errors (n = 65; 1.6 ± 0.7 mm; P < 0.001) than the center-track leads (n = 64; 1.2 ± 0.7 mm) were selectively track shifted. Track-shifted leads approached MRI targets in 86% (56/65 leads). Lower stereotactic errors tended to correlate with a better outcome (P = 0.095). Distances to MRI targets >2.5 mm tended to relate to a worse outcome (P = 0.087). Stereotactic errors were lower (n = 33; 0.9 ± 0.5 mm) in the GPi MRI group.

CONCLUSIONS: Multitrack DBS using intraoperative functional evaluation resulted in worse stereotactic accuracy than did MRI-guided DBS. However, track shifts in function-guided DBS can approach MRI targets effectively.