Objective. To evaluate the complications of bilateral contemporaneous pallidotomy in Parkinson's disease.
Background. Posteroventral pallidotomy is a recognized alternative in the management of severe Parkinson's disease with untreatable fluctuations. Methods. Four nondemented patients with advanced (Hoehn & Yahr stage 4) dopa-responsive Parkinson's disease with on-off fluctuations of the yoyoing type underwent contemporaneous bilateral ventral pallidotomy according to the technique described by Laitinen et al (1992). All patients had preoperative and postoperative careful evaluations according to the CAPIT protocol of assessment, except for PET scan, with additive neuropsychological testing, including personality and behavioral scales.
Results. All patients had a more than 40% improvement in the motor UPDRS score in both the best on and worst off states, and a mean 60% improvement in the complication of treatment subscale with an almost complete but persistent disappearance of dyskinesia; however, there was a more than 60% decrease in mean daily duration in off time. Activities of daily living (ADL) were improved by a mean of 30%. One patient had a partially regressive corticobulbar syndrome with dysphagia and dysarthria and increased drooling without emotional lability, but also had a bilateral postoperative pretarsal blepharospasm interfering with walking, which was well responsive to botulinum toxin injections. No one had visual field loss or hemiparesis. Changes in personality and behavior were found in two patients. In spite of a 40% improvement in motor and ADL, postoperative abulia was reported by the family of one patient who lost his preoperative aggressivity and drive in life; this patient also had loss of initiative in speech, business, family life, and hobbies, and more day sleepiness and fatigue. One patient reported postoperative mental automatisms (compulsive mental counting), as well as circular thoughts and reasoning in off phase, replacing preoperative depressive off mood. None of the patients reported these symptoms during microelectrode stimulation.
Conclusions. This careful evaluation of a small sample of patients who underwent bilateral contemporaneous pallidotomy shows that subtle neuropsychological changes of opposite presentation, such as abulia, mental automatism, or obsessive compulsive behaviors, have to be looked for in the postoperative evaluation of these patients.