ObjectiveAuthors evaluated the therapeutic effect of the MRI and microelectrodeguided stereotactic pallido- and pallido-thalamotomy in 33 patients with Parkinson's disease (PD), whose symptoms were refractory to pharmacological therapy. Matherial and methodsThe patients were evaluated according to the internationally standardized rating scales (UPDRS part II, III, Schawb & England, Hoehn & Yahr, and Fahn) at six timepoints: before the operation, and 2 days, 3, 6, 9 and 12 months postoperatively. The patients were divided into 2 groups. Those in group A had relief of all main parkinsonian symptoms after pallidotomy including tremor. The patients in group B had no relief of tremor after pallidotomy. For them the pallidotomy was completed by thalamotomy in the same sitting, which had resulted in cessation of tremor. ResultsThe following results were obtained by using the UPDRS part III: after pallidotomy “On state” mean: preoperative 51,2, postoperative at 2nd day 29,5 at 3, 6 and 9th month 26, and at 12th month 28,7. “Off state” mean: preoperative 64,3, postoperative at 2nd day 31,6, at 3, 6 and 9th month 26, and at 12th months 30,5. After pallidothalamotomy “On state” mean: preoperative 43,5, postoperative at 2nd day 27,9, at 3rd month 22,9, at 6th month 22,8, and at 9 and 12th month 24,5. “Off state” mean: preoperative 62,6, postoperative at 2nd day 38, at 3rd month 30, at 6th month 31,8 and at 9 and 12th month 33,8. ConclusionsFor those patients, whose tremor was not successfully controlled by pallidotomy, the combined pallido-thalamotomy was effective. The clinical symptomps, according to the rating scales, improved significantly in both groups (student t: P<0,0001), but bilateral lesioning carried higher surgical morbidity.