THE RESULTS, INDICATIONS, AND PHYSIOLOGY OF POSTEROVENTRAL PALLIDOTOMY FOR PATIENTS WITH PARKINSONS-DISEASE

IN THE PAST, stereotactic surgical intervention for Parkinson's diseas e was considered indicated only in those patients with active motor ma nifestations that were refractory to pharmacological therapy, manifest ations such as tremor, rigidity, dystonia, and dyskinesia. With the re introduction and refinement of Leksell's posteroventral pallidotomy, b oth akinetic and hyperkinetic symptoms are now amenable to surgical tr eatment. We have analyzed the results of 126 patients who underwent ei ther unilateral (n = 58) or bilateral (n = 68) posteroventral pallidot omies. The Unified Parkinson's Disease Rating Scale and Hoehn and Yahr Staging Scale were used for preoperative and postoperative objective assessments. Postoperative follow-up evaluation occurred initially at 1 week and subsequently at intervals between 1 and 12 months (mean = 4 .5 months) after surgery. Although individual motor subscores on the U nified Parkinson's Disease Rating Scale were significantly reduced (n = 126, P less than or equal to 0.01), the most dramatic findings were the reversal of akinetic symptoms and the elimination of dyskinesia an d profound ''off'' periods. These clinical results, combined with intr aoperative microelectrode records revealing pallidal neuronal hyperact ivity, suggest a reconsideration of the pathophysiology of akinesia an d point to possible mechanisms of akinesia improvement by posteroventr al pallidotomy in some parkinsonian subgroups.