Context: Subthalamic nucleus (STN) stimulation may be effective in ameliora
ting parkinsonian symptoms even to the extent to permit levodopa withdrawal
.
Objectives: To analyze the efficacy of STN stimulation in patients with Par
kinson disease (PD) and to determine if levodopa may be withdrawn after sur
gery.
Design: Before-after trial.
Setting: Referral center, hospitalized care.
Patients: Fifteen patients with advanced PD.
Interventions: Microelectrode-guided bilateral STN high-frequency stimulati
on.
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 stimulati
on 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, bra
dykinesia, 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 En
gland scores improved by 45.3%. Levodopa was withdrawn in 8 patients and th
e 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 rea
ched significance (P<.001). Stimulation of the STN achieved antiparkinsonia
n effect similar to that of treatment with levodopa. No life-threatening ad
verse effects occurred.
Conclusions: Bilateral STN stimulation safely improves all parkinsonian sym
ptoms, 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 quan
titatively comparable to that obtained with levodopa.