Long-term follow-up of unilateral pallidotomy in advanced Parkinson's disease

Background: Although the short-term benefits of posteroventral pallidotomy for patients with advanced Parkinson's disease have been well documented, l ittle is known about the long-term outcome of the procedure. Methods: We conducted a long-term follow-up study of a cohort of 40 patient s who had undergone unilateral posteroventral medial pallidotomy between 19 93 and 1996. Twenty patients were not evaluated because they had undergone a second surgical procedure (11 patients) or had died (2) or because they h ad dementia or another debilitating illness (4), lived too far away (1), or had been lost to follow-up (2). We conducted serial postoperative assessme nts of parkinsonism in the remaining 20 patients while they were taking med ications ("on'' period) and after overnight withdrawal of the drugs ("off" period). The mean follow-up time was 52 months (range, 41 to 64). Results: The combined off-period score for activities of daily living and m otor function on the Unified Parkinson's Disease Rating Scale was 18.0 perc ent better at the last evaluation than at base line (95 percent confidence interval, 4.9 to 31.0 percent; P=0.01). Significant improvements were also evident in the off-period scores for contralateral tremor (65.4 percent imp rovement, P=0.007), rigidity (43.2 percent, P=0.03), and bradykinesia (18.2 percent, P=0.04) and in the on-period score for contralateral dyskinesia ( 70.6 percent, P<0.001). Changes in medication did not contribute to the sus tained improvement. The 20 patients who could not be included in the long-t erm analysis had similar base-line characteristics but a worse response to surgery at six months. Conclusions: In the group of patients with advanced Parkinson's disease who could be enrolled in our long-term follow-up study of unilateral posterove ntral medial pallidotomy (20 patients from the original cohort of 40), sign ificant early improvements in off-period contralateral signs of parkinsonis m were sustained for up to 5 1/2 years. There was a sustained significant i mprovement in on-period contralateral dyskinesia but not in other on-period signs of parkinsonism. (N Engl J Med 2000;342:1708-14.) (C) 2000, Massachu setts Medical Society.