MICROELECTRODE-GUIDED POSTEROVENTRAL MEDIAL RADIOFREQUENCY PALLIDOTOMY FOR PARKINSONS-DISEASE

The outcome of radiofrequency-guided posteroventral medial pallidotomy was investigated in 29 patients with recalcitrant Parkinson's disease . Extracellular recordings were obtained in the target region to diffe rentiate the internal from the external globus pallidus, and distinct waveforms were recorded in reich region. Stimulation of the target sit e further verified the lesion location. Of the 29 patients treated dur ing the course of 1 year, none showed any adverse side effects (such a s hemianopsia or hemiparesis) from the procedure. Significant and imme diate improvement in motor involvement (dyskinesia. rigidity, dystonia . freezing, and tremor) was observed as measured by the Unified Parkin son's Disease Rating Scale and the Hoehn and Yahr scale. Patients expe rienced improvements in their condition as measured on a self-rating s cale, and their ability to perform the activities of daily living war also significantly improved. Although the onset and duration of the ef fect of a single dose of levodopa. did not change, the number of ho;ls in an ''off'' state of dyskinesia per day was significantly decreased . These results provide further evidence, in a large group of patients . that posteroventral medial pallidotomy results in significant contro l of the motor symptoms of Parkinson's disease with a minimum of undes irable side effects.