Twenty consecutive patients with idiopathic Parkinson's disease underwent s
tereotactic posteroventral pallidotomy. Schwab and England ADL scores in th
e "off' state were improved by 18% and in the "on" state the scores decline
d by 2%. Three patients also reported marked improvement in "off'' state dy
stonia. One-year data are available on 12 patients who underwent evaluation
s according to the Core Assessment Program for Intracerebral Transplantatio
n protocol preoperatively and at 3, 6, and 12 months after surgery. Signifi
cant improvements in Unified Parkinson's Disease Rating Scale sections II a
nd III scores in the "off" state, composite "off' state scores of bradykine
sia and rigidity, contralateral tremor in the "off' state, and contralatera
l dyskinesias were observed. Although there was reduction in the daily levo
dopa dose, this did not reach statistical significance. Major complications
(15%) included hemiparesis (one of 20) and visual field cuts (two of 20);
minor complications (45%) included mild cognitive dysfunction (four of 20),
reading difficulty not related to visual disturbance (one of 20), and 5-10
lb weight gain (four of 20).