Unilateral pallidotomy in advanced Parkinson's disease: a retrospective study of 26 patients.

OBJECTIVE: To evaluate the effects of unilateral pallidotomy in patients with Parkinson's disease (PD). PATIENTS AND METHODS: Twenty-six patients with PD and disabling dyskinesias, painful and/or disabling dystonia, and/or pain as part of PD despite optimal pharmacotherapy underwent unilateral pallidotomy. For assessment, the Unified Parkinson's Disease Rating Scale (UPDRS; part II and III), Hoehn and Yahr staging, the Schwab and England scale, a Dyskinesia Rating Scale, and timed tests were used. Assessment was performed in defined "off' and "on," and on average 2 months before and 7.5 months after the unilateral pallidotomy. Adverse effects were classified as transient or permanent and as major or minor. RESULTS: In the "off' phase, the median UPDRS II score improved from 26.5 to 20.5 (23%) and the median UPDRS III score improved from 47.5 to 33.0 (31%). In the "on" phase, dyskinesias contralateral to the side of the procedure improved with 88% ipsilateral dyskinesias improved only temporarily, and the total UPDRS II and III scores remained unchanged. Thirteen patients had transient adverse effects, three patients had permanent, and two patients had a combination of transient and permanent adverse effects. The transient adverse effects in two patients were classified as major. CONCLUSION: Stereotactic unilateral pallidotomy can improve symptoms and disability in the "off' phase. In the "on" phase, dyskinesias disappeared at the side contralateral to the procedure. Permanent minor complications of pallidotomy occurred in 19% of the patients.