Gamma Knife Thalamotomy and Pallidotomy in Medically Intractable Parkinsonian Tremor

Objective: Six patients with advanced Parkinson's disease (PD) underwent gamma knife radiosurgical procedures between October 1992 and September 1998. Methods: Four patients underwent thalamotomy, one patient was treated with pallidotomy. One patient received caudatotomy and thalamotomy. One woman and 5 men aged between 52 and 84 years (median 68 years) were followed-up over a period between 12 and 82 months (median 49 months) with MR and neurological means (UPDRS). Results: Of the four patients with thalamotomy three showed a good response while one remained stable [Unified Parkinson's Disease Rating Scale (UPDRS) improvement, off-drug-phase, motor score: 21%]. Ameliorated were the one with combined thalamotomy and caudatotomy (UPDRS: 9%) as well as the patient with pallidotomy (UPDRS: 15%). Severe side effects and complications were not noted, transient effects included one patient with swallowing problems and one with a paraparesis. Neuropsychological testing revealed no treatment morbidity. Conclusion: Gamma knife radiosurgery offers an interesting alternative to other stereotactical procedures with low morbidity and no mortality to a selected group of patients. Thalamotomy (VOA/VIM) for tremor may be a useful treatment for patients at high risk for surgery. More experience is needed before we can make a conclusive judgement.