Long-term follow-up review of cases of Parkinson's disease after unilateral or bilateral thalamotomy.

Follow-up reviews were carried out on 86 of 103 patients with Parkinson's disease who underwent unilateral or bilateral ventrolateral (VL) thalamotomy in the period from 1964 to 1969. Of these 86 patients, 64 received unilateral surgery, and 22 bilateral surgery. The follow-up periods were at least 10 years from the operation (from the second intervention in cases with bilateral procedures). In the group that received unilateral surgery, no progression after surgery was seen in three of six patients classified preoperatively in Grade I (Hoehn and Yahr's Grade 1), nine of 20 patients in Grade IIa (Hoehn and Yahr's Grade 2), 13 of 23 patients in Grade IIb (Hoehn and Yahr's Grade 3), and six of 15 patients in Grade III (Hoehn and Yahr's Grade 4). In the group that received bilateral surgery, one of three patients in Grade I and one of 11 patients in Grade IIa before the second intervention maintained continuous full social activities for over 10 years after the second surgery without any medication. In addition, eight of 11 patients classified preoperatively in Grade IIa and five of eight patients in Grade IIb seemed to show no progression after the second operation; four of 22 patients stopped taking their medication because of improvement in their symptoms. No patient who received bilateral surgery had progression of the disease to death. Observations suggested the efficacy of thalamic surgery, not only for improvement of motor symptoms but also for reducing progression of the disease, although no control study was made. Thalamotomy is still used to treat Parkinson's disease as an alternative to current medical treatments, such as L-dopa therapy.