Description of a Novel, Surgically Implanted Neuromodulatory Technique Known As Bilateral Epidural Prefrontal Cortical Stimulation (Epcs) for Treatment-Resistant Depression (TRD)

We describe the targeting, surgical technique, intraoperative testing, and postoperative programming strategy for the invasive neuromodulatory technique termed epidural prefrontal cortical stimulation (EpCS). While EpCS has been explored by several groups, the unique approach described here involves surgical placement of four epidural cortical stimulation paddles - two over the bilateral dorsolateral prefrontal cortex (DLPFC) and two over the frontopolar cortex (FPC). The safety and efficacy of this technique for treatment-resistant depression has been described previously by the authors. 5 subjects were implanted with EpCS (3 with major depression, 2 with bipolar affective disorder I, depressive type) and their depressive symptoms were followed for five years. Application of chronic electrical stimulation (10-15mA) across all four of these paddles produced a durable antidepressant response for 3 of 5 subjects at the five-year follow-up. This manuscript discusses the unique intraoperative testing strategy as well as the programming approaches employed in this study. We aim to give guidance into improving the effect size of this novel form of stimulation.