Background The last decade has witnessed a renaissance of functional stereotactic neurosurgery in the treatment of patients with movement disorders, especially advanced Parkinson’s disease (PD), essential tremor (ET) and dystonia. Ablative lesions such as thalamotomy and pallidotomy have been gradually replaced by the technique of chronic deep brain stimulation (DBS) applied to targets in the basal ganglia and thalamus, and assumed to be more lenient to the brain than stereotactic radiofrequency lesions. Since the aim of functional neurosurgery is to alleviate symptoms of these chronic, progressive, non-fatal diseases, and to improve life quality of the patients, it is imperative that the surgical procedures remain safe and do not result in complications mitigating any anticipated positive effect of the surgery on the symptoms of the disease.
Aim The aim of this thesis is to evaluate, compare and analyse the safety of various surgical procedures used to treat patients with movement disorders, and to document side effects and complications both peri operatively and in a long term follow-up. Further to compare the effects of pallidotomy and pallidal DBS, and to evaluate the longterm efficacy of Vim-DBS.
Method 256 consecutive surgical procedures, 129 DBS and 127 stereotactic lesions, were reviewed with respect to complications in 197 treated patients. In a series of 119 patients operated on with DBS during a 10 year period, the occurrence of hardware related complications (infection, breakage, erosion etc) was documented and analysed. Additionally, the interference of external magnetic field with the stimulation was documented. In one patient operated on with subthalamic nucleus DBS, a highly unusual and unexpected psychiatric side effect was carefully analysed. In 5 patients operated on with both methods (lesion and DBS) on each hemisphere, respectively, the effect and side effects of each method were compared. The long term effect and side effects of thalamic DBS was analysed in a series of patients with ET followed for 7 years.
Results There were no deaths and few severe neurological complications in this material. Unilateral ablative lesions in the pallidum were well tolerated by patients with advanced PD, while for tremor, thalamic DBS was much safer than thalamotomy, even if its effect on certain aspects of tremor could show some decrease of efficacy over time. Some of the side effects of lesioning are transient while most but not all side effects of DBS are reversible. Hardware-related complications were not uncommon especially in the early “learning curve” period, and the DBS technique, being a life-long therapy, will necessitate a life long follow up of patients. Provided safety protocols are followed and provided patient’s and carer’s education and awareness, external electromagnetic interference should not constitute a risk for patients with DBS. PD patients undergoing STN DBS should be carefully selected to avoid psychiatric or cognitive side effects, due to this brain target´s proximity to, and involvment in, non-motor associative and limbic circuitry.
Conclusions In terms of mortality and morbidity, modern stereotactic neurosurgery for movement disorders, both ablation and DBS, is a safe procedure even in advanced stages of disease. Symptoms of PD, ET and dystonia can be alleviated mainly with DBS and even unilaterally with pallidal lesions, at the expense of, in most cases, minor side-effects.
Umeå: Farmakologi och klinisk neurovetenskap , 2007. , 96 p.
deep brain stimulation, pallidotomy, thalamotomy, complications, Parkinson's disease, essential tremor