Stereotactic microelectrode-guided posteroventral pallidotomy and pallidal deep brain stimulation for Parkinson's disease.

Three patients underwent stereotactic posteroventral pallidotomy, and 1 patient underwent pallidal deep brain stimulation, for medically intractable symptoms of advanced Parkinson’s disease, characterized by peak-dose levodopa dyskinesias, wearing-off fluctuations , tremor, rigidity and bradykinesia. Surgery was performed stereotactically under local anaesthesia, with eventual target coordinates der ived from a combination of magnetic resonance imaging (MRI), coregistration with an electronic brain atlas, intraoperative microelectrode neuronal recordings and microstimulation before lesioning or placement of a deep brain stimulator was done. Assessment was made at basel ine preoperatively and at 3-month intervals postoperatively, with Unified Parkinson’s Disease Rating Scale (UPDRS) and Core Assessm ent Program for Intracerebral Transplantation (CAPIT) scoring. All patients improved in dyskinesia, tremor, rigidity and bradykines ia contralateral to the lesion side, but also on the ipsilateral side to a lesser extent. The improvement was largely seen in the ‘off’ state: UPDRS by 41%, and CAPIT by 19% on the contralateral side. ‘On’ freezing was not helped. There were no deaths and no visual complicati ons, but there was one complication of a delayed contralateral upper limb dystonia after pallidotomy. The 1 patient with pallidal deep b rain stimulation (DBS) obtained similar improvement as those with pallidotomy. Posteroventral pallidotomy and pallidal stimulation i mproves all the cardinal features of Parkinson’s disease, and effectively ameliorates levodopa dyskinesias. Ann Acad Med Singapore 1998; 27:767-71