Levodopa Withdrawal After Bilateral Subthalamic Nucleus Stimulation in Advanced Parkinson Disease

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Abstract
FUNCTIONAL neurosurgery is a valid therapy to relieve parkinsonian symptoms and drug-induced dyskinesias in patients with advanced Parkinson disease (PD). Unilateral ablative procedures, such as posteroventral pallidotomy, have mainly contralateral effects,1-4 and bilateral pallidotomy is typically avoided because it incurs a high risk for severe adverse effects. In contrast, high-frequency deep brain stimulation (HF-DBS) for the treatment of PD is a reversible, adaptable, and safe technique even when applied bilaterally,5,6 although serious adverse events can occur.7,8 The target for HF-DBS was initially directed toward the thalamus to treat tremor,6,9 and subsequently displaced to the internal pallidum.10-12 Subthalamic nucleus (STN) blockade was shown to be effective to alleviate parkinsonian symptoms in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)–treated primates.13-16 Posteriorly, STN stimulation was performed in humans with success. This technique proved to be effective to ameliorate PD symptoms and dyskinesias.7,8,17-19 Although several studies have suggested that long-term bilateral stimulation of the STN can produce an antiparkinsonian effect similar to that obtained with levodopa treatment,18 this has not been adequately assessed, because, in these studies, levodopa had not been withdrawn after surgery. Therefore, the specific effect produced exclusively by STN stimulation has not been evaluated.