Stereotactic neurosurgery for disabling tremor in multiple sclerosis: thalamotomy or deep brain stimulation?

Disabling tremor is common in multiple sclerosis and up to 75% of patients experience tremor at some point during their disease. The treatment of this tremor, however, remains challenging. Pharmacotherapy in general has been disappointing and stereotactic neurosurgery is becoming increasingly popular. However, the results of stereotactic treatments reported are variable and no systematic review has been performed. The aim of this study was to assess the role of thalamotomy and deep brain stimulation in the treatment of tremor in multiple sclerosis, and to compare the differences in efficacy and safety between the two techniques. We identified the relevant published studies and cases by searching the MEDLINE, EMBASS and the references lists of related articles, and performed a systematic review and assessment of the full texts of all articles selected. Initial tremor suppression was seen in 93.8% of patients who had thalamotomy and 96% in those who had deep brain stimulation. A total of 63.5% of patients had persistent tremor suppression at 12 months or more after thalamotomy. Twelve results for deep brain stimulation were not available in the reviewed literature. Functional improvement was seen only in 47.8% of those who underwent thalamotomy as opposed to 85.2% of those who had deep brain stimulation. While three of the four reported deaths were in patients who underwent thalamotomy, three of the four procedure-related haemorrhages followed DBS. Other common adverse effects like hemiparesis, dysarthria, swallowing difficulties, balance disorder, etc., was reported in both procedures. Numerous studies have attempted to assess the efficacy and safety of thalamotomy and DBS in the treatment of MS tremor, but no standardized outcome measures were used. Nonetheless, the data suggest that both thalamotomy and thalamic DBS are comparable procedures for tremor suppression and that adverse effects can occur with both procedures.