Outcome of unilateral pallidotomy in advanced Parkinson's disease: cohort study of 32 patients

Objectives-In a randomised trial to study the efficacy of unilateral pallid otomy in patients with advanced Parkinson's disease, patients having pallid otomy within 1 month after randomisation were compared with patients having pallidotomy 6 months after the primary outcome assessment. Of the 37 patie nts enrolled 32 had a unilateral pallidotomy. The follow up study of these patients is presented to report (1) clinical outcome; (2) adverse effects; (3) cognitive and behavioural effects; (4) relation between lesion location and outcome; and (5) preoperative patient characteristics predictive for g ood outcome. Methods-Outcome measures were the motor section of the unified Parkinson's disease rating scale (UPDRS), levodopa induced dyskinesias, disability, qua lity of life, and a comprehensive neuropsychological assessment. Multivaria te logistic regression was used to identify preoperative patient characteri stics independently associated with good outcome. Results-Off phase assessment showed a reduction in parkinsonism from 49 to 36.5 points on the UPDRS 6 months after surgery. Improvements were also dem onstrated for activities of daily living and quality of life. In the on pha se dyskinesias were reduced. All effects lasted up to 12 months after surge ry. Three patients had major permanent adverse effects. Besides worsening o f verbal fluency after left sided surgery, systematic cognitive deteriorati on was not detected. Patients taking less than 1000 levodopa equivalent uni ts (LEU)/day were more likely to improve. Conclusions-The positive effects of unilateral pallidotomy are stable up to I year after surgery. Patients taking less than 1000 LEU per day were most likely to improve.