Our landmark clinical study was published in “Brain” in 2014 and the results are currently being reproduced by a study of chronically implanted patients in Germany. The outcome of our first study concluded that:
“Intraoperative directional stimulation with a smaller activated tissue volume in the subthalamic nucleus and the nucleus ventralis intermedus significantly widened the therapeutic window for DBS in comparison to omnidirectional stimulation. There were also clear differences in stimulation induced effects depending on the angular orientation of the stimulating electrode contact around the circumference of the electrode shaft”.
The conclusion was very promising reporting that:
“Although these results warrant further studies to confirm the long-term effect of directional stimulation in chronically implanted patients, they clearly suggest that directional stimulation has a strong potential for reducing side effects, widening the therapeutic window, and lowering the therapeutic current. This new approach may open the door to a better DBS therapy, by minimizing the impact of suboptimal lead placement and by prolonging battery life”.
Several studies conducted on directional leads have demonstrated the observations of our landmark clinical study 5 showing that
“Stimulation with segmented leads with reduced electrode size was associated with a significant reduction of VTA and a significant increase of radial distance in the best direction of stimulation”.
This more uniform and homogeneous stimulation is also one of the reasons for decreased side effects as “While beneficial effects were associated with activation volumes confined within the anatomical boundaries of the subthalamic nucleus at therapeutic currents, side effects were associated with activation volumes spreading beyond the nucleus’ boundaries”
4 Claudio Pollo, Alain Kaelin-Lang, Markus F. Oertel, Lennart Stieglitz, Ethan Taub, Peter Fuhr, Andres M. Lozano, Andreas Raabe, Michael Schüpbach; Directional deep brain stimulation: an intraoperative double-blind pilot study; Brain, Volume 137, Issue 7, July 2014, Pages 2015–2026.
5 T. A. Khoa Nguyen, Milan Djilas, Andreas Nowacki, André Mercanzini, Michael Schüpbach, Philipp Renaud, Claudio Pollo; Analysis of patient-specific stimulation with segmented leads in the subthalamic nucleus PLOS ONE, June 19, 2019