Unilateral pallidotomy for Parkinson's disease: results after more than 1 year

Objective-To examine follow up results of unilateral ventral medial pallido tomy in 22 patients with advanced Parkinson's disease more than 1 year afte r the operation in comparison with their results (previously reported) at 3 months. Methods-Twenty patients who had undergone unilateral pallidotomy were asses sed with the core assessment programme for intracerebral transplantation (C APIT) protocol preoperatively, at 3 months postoperatively, and again after a median postoperative follow up of 14 months. Two further patients had on ly one evaluation 3 months postoperatively. Results-The reduction of contralateral dyskinesias (median 67%) at 3 months was slightly attenuated after 1 year to 55% (both p<0.001 compared with ba seline). A less pronounced effect on ipsilateral and axial dyskinesias decr eased from 39% to 33% (p<0.005 and p<0.01), and from 50% to 12.5% (p<0.001 and p<0.01), respectively. However, there was no significant change between the 3 month and the follow up assessment. The modest improvement of the co ntralateral unified Parkinson's disease rating scale (UPDRS) motor score in the "off" state remained improved compared with preoperative levels, but l ess significantly (26%, p<0.001, and 18%, p<0.01). The activities of daily living (ADL) subscore of the UPDRS in the off state remained improved with median changes of 23% and 22% at follow up (both p<0.005). There was no sig nificant improvement of "on" state or ipsilateral off state motor scores. M edian modified Hoehn and Yahr scores in off and on state were unchanged, as was the time spent off. Speech in off had significantly deteriorated by 1 year after the operation. Conclusions-The beneficial effects of unilateral pallidotomy persist for at least 12 months and, dyskinesias are most responsive to this procedure.