An Institutional Experience of Directional Deep Brain Stimulation and a Review of the Literature

Abstract

Introduction: Directional deep brain stimulation (dDBS) has been suggested to have a similar therapeutic effect when compared with the traditional omnidirectional DBS, but with an improved therapeutic window that yields optimized clinical effect owing to the ability to better direct, or "steer," electric current. We present our single-center, retrospective analysis of our experience in the use of dDBS in patients with movement disorders and provide a review of the literature.

Materials and methods: We identified all patients with Parkinson disease (PD) and essential tremor (ET) who received a dDBS system between 2018 and 2022 and retrospectively examined characteristics of their longitudinal treatment. A total of 70 leads were identified across 42 patients (28 PD, 14 ET).

Results: Three types of systems were implemented (single-segment activation, 45.2% of patients; multiple independent current control, 50.0%; and local field potential sensing-enabled, 4.7%). The subthalamic nucleus or globus pallidus internus was targeted in PD, and the ventral intermediate nucleus of the thalamus in ET. Across the entire cohort (n = 70 leads), at initial programming, 54.2% of leads (n = 38) were programmed using directional stimulation. At the most recent reprogramming, 58.6% of leads (n = 41) implemented directionality. In patients with PD, the average decrease in levodopa-equivalent daily dose at six months after implantation was 35.4% ± 39.2%. Despite the ability to steer current to relieve stimulation-induced side effects, ten leads in six patients required surgical revision owing to electrode malposition.

Conclusions: We show wide adaptability and implementation of directional stimulation, adding to the growing compendium of real-world uses of dDBS therapy. We used directionality to improve clinical response in both patients with PD and patients with ET and found that its programming flexibility was used at high rates long after implantation and initial programming. In patients with PD, dDBS led to a significant reduction in dopaminergic medication, suggesting sustained clinical improvement. Nonetheless, accurate surgical placement remains necessary to ensure optimal clinical outcomes.

Keywords: Directional DBS; Parkinson disease; essential tremor; neuromodulation; subthalamic nucleus.