Directional PSA Versus STN DBS for TD-PD

This single-center trial utilizes directional deep brain stimulation (DBS) current-steering technology to compare the clinical efficacy and tolerability of the posterior subthalamic area (PSA) versus the subthalamic nucleus (STN) for the treatment of tremor-dominant Parkinson's disease (TD-PD) within the same subject. The study is optimized into a two-phase framework to maximize patient safety and protocol compliance: Phase 1: Two-month post-implantation, acute mapping is conducted to define the therapeutic window for PSA and STN configurations in a blinded randomized order. If a configuration induces immediate, unmanageable adverse events before reaching efficacy, it is classified as "intolerant" and excluded from that participant's subsequent chronic phase. Phase 2 (Chronic Crossover): Participants with tolerated configurations are entered into a chronic randomized phase with a blinded sequence of 2-month PSA or STN chronic stimulation. Following the core two-arm crossover, all eligible patients transition into an open-label, exploratory sequential add-on phase of 2-month with combined PSA+STN stimulation to evaluate potential synergistic benefits. All participants will then be followed-up up to 12 months after surgery.