GPi‐DBS for KMT2B‐Associated Dystonia: Systematic Review and Meta‐Analysis

• Published in: Movement disorders clinical practice (Hoboken, N.J.) Vol. 9; no. 1; pp. 31 - 37
• Main Authors: Rajan, Roopa, Garg, Kanwaljeet, Saini, Arti, Radhakrishnan, Divya M., Carecchio, Miryam, BK, Binukumar, Singh, Manmohan, Srivastava, Achal K.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.01.2022; Wiley Subscription Services, Inc
• Subjects: BFMDRS; deep brain stimulation; Dystonia; KMT2B; Meta-analysis; Review; Reviews; Systematic review; BFMDRS; meta‐analysis; dystonia; deep brain stimulation; KMT2B
• ISSN: 2330-1619; 2330-1619
• DOI: 10.1002/mdc3.13374

ABSTRACT Background Early evidence suggests good response to pallidal deep brain stimulation (DBS) in DYT‐KMT2B. Objectives We aimed to conduct a systematic review and meta‐analysis to assess outcomes and identify predictors of good outcome following GPi‐DBS in DYT‐KMT2B. Methods We searched MEDLINE, Cochrane and MDS‐s databases using the MeSH terms “KMT2B and DYT28”. We included studies that reported objective outcomes following GPi‐DBS in DYT‐KMT2B. The BFMDRS‐M (Burke‐Fahn‐Marsden Dystonia Rating Scale‐ Movement) total scores pre‐ and post‐surgery were used to quantify outcomes. We calculated pooled effects using a random effects meta‐analysis and used meta‐regression to identify potential effect modifiers. Multiple linear regression using individual patient data was used to identify predictors of good outcome (>50% improvement from baseline on BFMDRS‐M). Results Initial searches screened 132 s of which 34 full‐text articles were identified to be of potential interest. Ten studies reporting 42 individual patients, met the inclusion/exclusion criteria and were included in the final review. The mean age at onset was 6.4 ± 5.7 years and 40% were male. The median follow‐up was 12 months (range: 1–264 months). GPi‐DBS resulted in median BFMDRS‐M improvement of 42.7% (range: −103.5% to 95.9%) postoperatively. Pooled proportion of patients experiencing clinical improvement >50% on BFMDRS‐M was 41% (95% CI: 27%–57%). Male gender [β: 22.6, 95% CI: 8.0–37.3, P = 0.004), and higher pre‐operative BFMDRS‐M score [β: 0.62, 95% CI: 0.36–0.87, P < 0.001) were independently associated with better outcome. Conclusion KMT2B‐associated dystonia responds effectively to pallidal stimulation. The outcome is better in males and those with more severe dystonia at baseline.