Which one is the superior target? A comparison and pooled analysis between posterior subthalamic area and ventral intermediate nucleus deep brain stimulation for essential tremor.

The efficacy and safety of posterior subthalamic area (PSA) and ventral intermediate nucleus (VIM) deep brain stimulation (DBS) in the treatment of essential tremor (ET) have not been compared in large-scale studies. We conducted a secondary analysis to identify the superior target of ET-DBS treatment. PubMed, Embase, Cochrane Library, and Google Scholar were searched for relevant studies before September 2021. The tremor-suppression efficacy and rate of stimulation-related complications (SRCR) after PSA-DBS and VIM-DBS treating ET were quantitatively compared. Secondary outcomes, including tremor subitem scores and quality of life results, were also analyzed. Subgroup analyses were further conducted to stratify by follow-up (FU) periods and stimulation lateralities. This study was registered in Open Science Framework (DOI: 10.17605/OSF.IO/7VJQ8). A total of 23 studies including 122 PSA-DBS patients and 326 VIM-DBS patients were analyzed. The average follow-up time was 12.81 and 14.66 months, respectively. For the percentage improvement of total tremor rating scale (TRS) scores, PSA-DBS was significantly higher, when compared to VIM-DBS in the sensitivity analysis (p = 0.030) and main analysis (p = 0.043). The SRCR after VIM-DBS was higher than that of PSA-DBS (p = 0.022), and bilateral PSA-DBS was significantly superior to both bilateral and unilateral VIM-DBS (p = 0.001). This study provided level IIIa evidence that PSA-DBS was more effective and safer for ET than VIM-DBS in 12-24 months, although both PSA-DBS and VIM-DBS were effective in suppressing tremor in ET patients. Further prospective large-scale randomized clinical trials are warranted in the future.