Efficacy and safety of single-trajectory posterior subthalamic area and subthalamic nucleus deep brain stimulation for dystonic tremor: a retrospective pilot study

OBJECTIVE: To evaluate the feasibility, safety, and preliminary efficacy of a novel single-lead, dual-target deep brain stimulation (DBS) approach targeting the posterior subthalamic area (PSA) and subthalamic nucleus (STN) for dystonic tremor. METHODS: This retrospective pilot study reviewed outcomes of six consecutive patients with medically refractory dystonic tremor who underwent single-lead PSA-STN DBS at our center (June-December 2024). Clinical outcomes were assessed using the BFMDRS and FTMTRS scales. A formal blinded crossover assessment was performed in three patients to compare PSA-only, STN-only, and combined stimulation. Chronic settings were selected via patient-directed optimization. RESULTS: All six patients completed follow-up (100% retention) and achieved stable chronic stimulation programs. Five patients (83.3%) independently selected combined PSA + STN stimulation; one preferred STN-only. At LFU (6-12 months postoperatively), the mean BFMDRS-Motor score decreased by 78.1% and FTMTRS by 87.1%. The crossover assessment (n = 3) showed that combined stimulation outperformed single-target stimulation. No serious adverse events occurred. All efficacy analyses are exploratory. CONCLUSION: This single-lead, dual-target PSA-STN DBS approach demonstrates feasibility and preliminary efficacy for dystonic tremor. Prospective controlled trials are warranted.