Supplementary Material for: Radiofrequency lesioning for hemidystonia: a systematic review and meta-analysis with individual patient data

Background
Radiofrequency lesioning (RL) had been a mainstay in functional neurosurgery for dystonic movement disorders before the widespread adoption of deep brain stimulation (DBS). Outcomes of RL in hemidystonia have varied. This review provides a systematic analysis of RL for hemidystonia and evaluates the spectrum of clinical outcome.

Methods
A systematic literature review was performed according to PRISMA guidelines in PubMed, Embase, and Web of Science using a customized software (UiPath, NY) to identify all case reports, case series, and cohort studies reporting patients with hemidystonia treated with RF. Manuscripts were automatically searched for the term "hemidystonia". The selected manuscripts were then manually screened. Detailed information from two recent multi-patient studies was added. Clinical improvement was classified as follows: (0) no improvement; (I) mild; (II) moderate; (III) marked improvement.

Results
Twenty-eight studies with individual patient data were included, totaling 101 cases published between 1962 and 2024. Thalamotomy was performed in 80 cases, pallidotomy in 16, and both in 5. At last follow-up, 18 patients (19.35%) showed marked improvement, 41 (44.09%) moderate, 16 (17.21%) mild, and 18 (19.35%) no benefit. No significant differences in outcomes were found between targets or etiologies, though patients with traumatic brain injury tended to fare worse. A significant negative linear correlation was found between the degree of improvement and age at surgery.

Conclusion
With advancements in targeting and technology, RL may be reconsidered as a treatment option for hemidystonia. Further studies with standardized outcome assessments are needed to better characterize response variability and identify prognostic factors.