[Medial posteroventral pallidotomy for the treatment of Parkinson's disease]

Abstract

Stereotactic medial posteroventral pallidotomy for treatment of Parkinson's disease attracts increasing attention. We report on the preliminary results of 12 patients at 1 year after microelectrode-guided unilateral pallidotomy. The primary indications were severe bradykinesia and levodopa-induced dyskinesias. After radiofrequency lesioning all patients had immediate improvement of contralateral parkinsonian signs. Postoperative magnetic resonance imaging confirmed the localization of the lesions. At the 1-year follow-up, all patients had sustained benefit. The global improvement was rated as moderate in six cases, and as marked in six other cases. The mean values of various subscores of the Unified Parkinson's Disease Rating Scale (UPDRS) showed highly significant changes in the "off" state (pre/postoperatively): UPDRS Motor score (60.3/31). UPDRS Activities of Daily Living (ADL) score (33.2/18.3), gait/postural stability score (13.8/7.0), and subscores for contralateral rigidity (4.9/2.1), tremor (7.1/1.4) and bradykinesia (11.6/5.3). There was also significant improvement of ipsilateral bradykinesia and rigidity. Furthermore, we found significant changes of the mean values of the UPDRS ADL and motor "on" scores, an increase of the percentage of "on" time with reduced on-off fluctuations, and a decrease of the percentage of levodopa-induced dyskinesias, with marked improvement or complete abolition of contralateral dyskinesias in particular. The preoperative levodopa regimen was maintained, in general, or only slightly modified, if necessary. Two patients had transient complications: one patient suffered postoperative pneumonia and altered mental status; another patient displayed mild Broca's aphasia secondary to a small stroke involving the dorsal thalamus and the adjacent white matter. There were no persistent side effects at the 1-year follow-up. Contemporary unilateral pallidotomy is an effective and promising therapeutical option for surgical treatment of advanced Parkinson's disease.