Efficacy and Complications of Bilateral Vim Lesioning and Bilateral Vim Deep Brain Stimulation for Essential Tremor: Parallel Single-Arm Meta-Analyses and an Exploratory Matched Indirect Comparison.

BACKGROUND: Bilateral ventral intermediate nucleus (Vim) deep brain stimulation (DBS) is an established treatment for essential tremor, but infection, lead migration or fracture, and the need for battery replacement remain concerns. Bilateral Vim lesioning may offer an alternative, although comparative evidence is limited. We aimed to estimate efficacy and complication rates and to explore differences between modalities. METHODS: We conducted a systematic review and meta-analysis. MEDLINE, EMBASE, CENTRAL, ClinicalTrials.gov, and ICTRP were searched through May 14, 2025. The protocol was registered with OSF. Eligible studies included patients with essential tremor undergoing bilateral Vim DBS or lesioning and reporting tremor outcomes and predefined complications. Risk of bias was assessed using MINORS. Mean tremor score changes were pooled using random-effects models; complication rates were synthesized using binomial generalized linear mixed models. RESULTS: Thirteen studies provided eligible single-arm data for 269 patients: 199 treated with DBS and 70 with lesioning. No randomized head-to-head trial was identified. Pooled mean changes in CRST Parts A+B were -25.4 points after DBS and -23.5 after lesioning; corresponding changes in Parts A+B+C were -33.0 and -36.5. Speech disturbance occurred in 26.1% after DBS and 15.4% after lesioning; ataxia occurred in 15.6% and 12.9%, respectively. Sensory disturbance was reported mainly after lesioning, occurring in 22.9% of lesioning patients, and often persisted. Most complications were mild; none were severe. CONCLUSIONS: Both procedures were associated with reduced tremor scores. Comparative efficacy remains uncertain, and complication profiles differed. Lesioning avoids implanted hardware but may be associated with persistent sensory symptoms.