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|Leo Verhagen, MD|| |
Two decades after its introduction into clinical medicine, deep brain stimulation (DBS) has finally become part of standard care for patients with a variety of movement disorders who find insufficient benefit from medical therapy alone.
The modern DBS era started in 1987 when the Grenoble group in France, under guidance of Benabid and Pollak, reported on the efficacy of thalamic DBS for Parkinsonian tremor. In the United States it took until 1999 before the FDA approved thalamic DBS for both Parkinsonian and essential tremor not controlled by medications.
Bilateral DBS of the subthalamic nucleus was first reported to be effective for all motor symptoms (not just tremor) of advanced PD in the early nineties, but FDA approval of STN DBS (and pallidal DBS) in the United States was not granted until 2002. Finally, in 2003 bilateral pallidal DBS for dystonia was approved under a humanitarian device exemption (HDE).
There are multiple reasons why the development of DBS into a mainstream clinical therapeutic option took so long. From the regulatory and scientific point of view, a major reason was the lack of prospective, randomized, controlled trials of surgical therapy versus best medical management. From the clinical point of view, the invasiveness of the procedure, the unknown long-term benefits and side effects, and the unclear patient selection criteria, were reasons for traditional neurologists to not immediately embrace this new therapy. In addition, from a practical point of view, it took time for clinicians to realize that this multifaceted treatment option should be performed in a multidisciplinary team setting, and that such teams needed to be developed and incorporated into movement disorder centers.
Now that DBS has come of age, many of the above issues and uncertainties have been addressed and clarified. For instance, the benefits and risks associated with DBS, both acute and long-term, are now reasonably well established. In addition, over the years it has become increasingly clear what the selection criteria for DBS are; in other words, which patients are good candidates for surgery, which are not, and what pre-operative factors predict a good outcome of DBS. Furthermore, there are now well-established DBS centers that specialize in the selection, surgery and postoperative management of patients using a truly multi-disciplinary approach. As a result, more than 80,000 DBS procedures have been performed worldwide and the number of DBS surgeries will continue to increase.