ABSTRACT
<p><b>OBJECTIVE</b>To assess postoperative effects of microelectrode-guided posteroventral pallidotomy (PVP) for Parkinson's disease.</p><p><b>METHODS</b>Intraoperative microelectrode recordings and microstimulation were used to explore the globus pallidus to performance of posteroventral pallidotomy in 48 patients with Parkinson's disease (47 unilateral and 1 bilateral). Assessment was made at baseline preoperatively and at 6 months intervals postoperatively, with unified Parkinson's disease rating scale (UPDRS).</p><p><b>RESULTS</b>All patients were significantly improved on the limbs contralateral to the lesion side 6 - 34 months after operation (mean 24 months). The improvement was seen in the 'on' or 'off' state: UPDRS scores with patients on levodopa were improved by an average of 28.7%, while off medication scores showed reductions (47.6%) at 24 months. There were no deaths and no visual complications, but there were 4 patients (8.3%) of a delayed contralateral limbs dystonia after pallidotomy.</p><p><b>CONCLUSIONS</b>The techniques of microelectrode recording and microstimulation indicate the location of the internal capsule and optic tract, which allow easy identification of these structure and facilitate PVP target in conjunction with radiofrequency microelectrode stimulation.</p>