Correlation of electrode position and clinical outcomes in globus pallidus stimulation for dystonia

The correlation between the electrode location and the clinical outcome for internal globus pallidus (GPi) deep brain stimulation (DBS) has not been fully elucidated.

The aim of this study was to determine the discrepancies between the theoretical target planned by magnetic resonance imaging (MRI) and the actual electrode location in postoperative MRI, as well as to find the correlation between the final electrode locations and the clinical outcome after GPi DBS.

Thirty-six patients who underwent GPi DBS for dystonia were included in this retrospective study. The X coordinate was defined as the lateral distance from the midline, the Y coordinate as the anterior distance from the midcommissural point, and the Z coordinate as the inferior distance from the intercommissural line.

All coordinates showed a significant difference between theoretical and actual values for all electrode locations (p < 0.05). In particular, greater differences were exhibited for Y than for the X and Z coordinates. There was no significant difference in the accuracy of the localization of the left-side versus the right-side electrode for any coordinates. The patients whose electrodes were located within or near the posteroventral GPi showed better clinical outcomes.

The actual electrode location was slightly more posterior to the theoretically planned target. Electrodes concentrated near the posteroventral GPi tended to yield favorable outcomes.