Expanding indications for deep brain stimulation.

It has been three decades since the first application of deep brain stimulation (DBS) for tremors was described by Benabid. Over the years, the indications for the performance of DBS have been expanding. There are now more than 1,50,000 patients around the world who have undergone DBS for various disorders. The main appeal of DBS is in its reversibility and titratability. Though the initial interest in DBS was for pain, the main indications for DBS have been movement disorders. Despite its wide appeal and "perceived" advantage, United States Food and Drug Administration, the nodal agency for approving therapies, has been cautious and guarded in providing approvals. Only two indications, i.e., Parkinson's disease and tremors, have been approved; the two other indications, i.e., dystonia and obsessive compulsive disorder (OCD), have been granted exemption under the humanitarian device usage. However, the European community has been more liberal and several of these indications have CE (Conformite Europeene) approval. Most of them will be reviewed in this article. There have been numerous indications for which DBS has been applied, which in turn has helped to change the lives of several patients. Unfortunately, due to the paucity of the number of procedures performed and the inherent difficulty in conducting "surgical" double blind randomized trials, Class 1 or Class 2 evidence for several of these indications is lacking. Hence, it is advisable that one does not embark on using each and any target for each and any indication without having the understanding or the team backup. It is cautionary that most of these therapies should be conducted in an institutional setting with an ethics and scientific committee backup and ably assisted by an experienced team.