Surgical therapy for multiple sclerosis tremor: a 12‐year follow‐up study

Background and purpose: Severe multiple sclerosis (MS) tremor causes disability poorly responsive to medication. Deep brain stimulation (DBS) or thalamotomy can suppress tremor, but long‐term outcomes are unclear. Methods: Nine patients with MS tremor underwent disability measures at baseline and 12 months post‐surgery (six thalamotomy, three DBS) in 1997–1998 (previously reported, Matsumoto et al., Neurology 2001;57:1876–82). We report the prospective 12‐year follow‐up of this cohort for tremor, disability, and death. Results: Surgery was initially successful in all. Tremor recurred in all patients within median 3 months, although two DBS patients were tremor‐free for 5 years. Median tremor‐free survival (tremor‐free time/survival time) was 4.3%. At 12‐year follow‐up, four survivors (two thalamotomy, two DBS) (Expanded Disability Status Scale scores 8–8.5) were severely disabled. Five patients were dead (four thalamotomy, one DBS) median 5.8 years post‐operative. Conclusions: Surgery benefit for severe tremor was overall short‐lived (median 3 months), with long‐term poor prognosis. Although two DBS patients had sustained 5‐year tremor‐suppression, the observed progressive disability and death in this cohort bear importance for long‐term success in future MS tremor surgery trials.