Context: Subthalamic nucleus (STN) stimulation may be effective in ameliorating parkinsonian symptoms even to the extent to permit levodopa withdrawal.
Objectives: To analyze the efficacy of STN stimulation in patients with Parkinson disease (PD) and to determine if levodopa may be withdrawn after surgery.
Design: Before-after trial.
Setting: Referral center, hospitalized care.
Patients: Fifteen patients with advanced PD.
Interventions: Microelectrode-guided bilateral STN high-frequency stimulation.
Outcome measures: Before surgery patients were evaluated in off-medication and on-medication conditions. Dopaminergic drug dosages were reduced after surgery, aiming for complete withdrawal. Six months after surgery, patients were reeavaluated in off- and on-medication conditions, with the stimulation turned on and off.
Results: Total Unified Parkinson's Disease Rating Scale (UPDRS) motor score in the off-medication condition improved by 65.9%; and axial symptoms, bradykinesia, rigidity, and tremor improved by 65.8%, 60.4%, 66.1%, and 81.1%, respectively. UPDRS part II scores were reduced by 71.8% and Schwab and England scores improved by 45.3%. Levodopa was withdrawn in 8 patients and the overall levodopa dose was reduced 80.4%. "Off" time was reduced 89.7% and the severity of dyskinesias decreased 80.6% after surgery. All results reached significance (P<.001). Stimulation of the STN achieved antiparkinsonian effect similar to that of treatment with levodopa. No life-threatening adverse effects occurred.
Conclusions: Bilateral STN stimulation safely improves all parkinsonian symptoms, decreases or eliminates the need for levodopa, and ameliorates motor fluctuations and dyskinesias. Complete withdrawal of levodopa is feasible with this technique and the overall motor effect of STN stimulation is quantitatively comparable to that obtained with levodopa.