Unilateral pallidotomy versus bilateral subthalamic nucleus stimulation in Parkinson's disease: one year follow-up of a randomised observer-blind multi centre trial

Background. To investigate whether STN stimulation is more efficacious than unilateral pallidotomy in advanced Parkinson's disease (PD) one year after surgery. Method. Thirty-four patients with advanced PD were randomly assigned to unilateral pallidotomy or bilateral STN stimulation. Outcome measures were parkinsonian symptoms in off and on phases (UPDRS 3), dyskinesias, functional status, Parkinson's disease quality of life questionnaire, the effects on separate symptoms, timed tests, patient diaries, dopaminergic drugs changes, adverse effects, and global outcome scale. Patients were assessed before surgery, six months and one year after surgery. The primary outcome measure was the off phase UPDRS 3 at six months follow-up. Findings. The off phase UPDRS 3 score improved from 46.5 to 32 points in the pallidotomy patients and from 51.5 to 24 in the STN stimulation patients (p = 0.002). On phase UPDRS 3 and off phase Schwab and England functional scale improved significantly in favour of the STN stimulation patients. Dopaminergic drugs reduction was larger in the STN group although the difference between the treatment groups was not significant. One patient in each group had a major adverse effect. Conclusions. Bilateral STN stimulation is more efficacious than unilateral pallidotomy in advanced PD up to one year after surgery.