Gamma Knife Thalamotomy for Essential Tremor: A Retrospective Analysis

BACKGROUND: Gamma knife (GK) thalamotomy has been used as a treatment option for essential tremor (ET). Numerous studies on GK use in ET treatment have reported more varied responses and complication rates.METHODS: Data from 27 patients with ET who underwent GK thalamotomy were retrospectively analyzed. The Fahn-Tolosa-Marin Clinical Rating Scale for Tremor, handwriting, and spiral drawing were evaluated. Postoperative adverse events and magnetic resonance imaging findings were also evaluated.RESULTS: The mean age at GK thalamotomy was 78.1 & PLUSMN; 4.2 years. The mean follow-up period was 32.5 & PLUSMN; 19.4 months. The preoperative postural tremor, handwriting, and spiral drawing scores were 3.4 & PLUSMN; 0.6, 3.3 & PLUSMN; 1.0, and 3.2 & PLUSMN; 0.8, respectively, all of which showed significant improvements to 1.5 & PLUSMN; 1.2 (55.9% improvement, P < 0.001), 1.4 & PLUSMN; 1.1 (57.6% improvement, P < 0.001), and 1.6 & PLUSMN; 1.3 (50% improvement, P < 0.001), respectively, at the available final follow-up evaluations. Three patients presented with no improvement in tremor. Six patients presented with adverse effects, including complete hemiparesis, foot weakness, dysarthria, dysphagia, lip -umbness, and finger numbness, at the final follow-up period. Two patients presented with serious complications, including complete hemiparesis due to massive widespread edema and chronic encapsulated expanding hematoma. One patient died of aspiration pneumonia following severe dysphagia secondary to chronic encapsulated expanding hematoma.CONCLUSIONS: GK thalamotomy is an efficient procedu re for treating ET. Careful treatment planning is necessary to reduce complication rates. The prediction of radiation complications will increase the safety and effectiveness of GK treatment.