Pallidotomy for Parkinson disease: a review of contemporary literature

Object. The authors conducted an evidence-based review of contemporary published articles on pallidotomy to obtain an appraisal of this procedure in the treatment of Parkinson disease (PD). Methods. A search of the Pubmed database performed using the key word "pallidotomy" yielded 263 articles cited between January 1, 1992, and July 1, 1999. Articles that included original, nonduplicated descriptions of patients with PD treated with radiofrequency pallidotomy were selected. In 85 articles identified for critical review, 1959 patients with PD underwent pallidotomies at 40 centers in 12 countries. There were 1735 unilateral (88.6%) and 224 bilateral procedures (11.4% ). The mean age of the patients was 61.4 +/- 3.6 years and the mean duration of PD symptoms in these patients was 12.3 +/- 1.9 years. Microelectrode recordings were used in 36.2% of cases. Outcomes were objectively documented using the Unified Parkinson Disease Rating Scale (UPDRS) in 501 (25.6%) of the cases at 6 months and in 218 (11.1%) of the cases at 1 year. There was a consensus on the benefits of pallidotomy for off period motor function and on period, drug-induced dyskinesias, with variations in the extent of symptomatic benefit across studies. At the 1-year assessment, the mean improvement in the UPDRS motor score during off periods was 45.3% and the mean improvement in contralateral dyskinesias during on periods was 56.4%. The overall mortality rate was 0.4% and the rate of persistent adverse effects was estimated at 14%. Major adverse events, including intracerebral hemorrhages, contralateral weakness, and visual field defects, occurred in 5.3% of patients reported. Conclusions. Unilateral pallidotomy is effective and relatively safe in the treatment of PD; however, limited data are available on the long-term outcome of this procedure.