Indications for surgical treatment of Parkinson's disease after levodopa therapy.

The results of stereotactic thalamotomy in the treatment of 32 patients with Parkinson's disease are described. The outcome is compared with reports from the literature and with the author's former results with patients not treated with levodopa preoperatively. Especially, ipsilateral tremor aggravation is caused more frequently. Also the quite disappointing results of bilateral thalamotomy are briefly mentioned. The location of the lesion and its possible relation to the side-effects are discussed. On the basis of the outcome described, the indication for the operation seems to be a tremor, not necessarily unilateral, which is resistant to all medications available for Parkinson's disease. Such medication is given for a period of some months after the pros and cons have been thoroughly discussed with the candidate.