Deep Brain Stimulation in Patients Suffering from Movement Disorders - Stereotactic Procedure and Intraoperative Findings

Introduction: Deep brain stimulation (DBS) is the method of choice in the treatment of various movement disorders. Methods: Between 1998 and 2009, we performed DBS in 100 patients (F : M = 37 : 63; median 56 yrs /12-73 yrs/). Fourteen patients suffered from essential tremor (ET), 2 from tremor of other aetiology (T), 73 from Parkinson's disease (PD), 10 from generalized (GD) and 1 from cervical (CD) dystonia. Implantation was targeted in the ventral intermedial thalamus (VIM) for ET, T and PD, subthalamic nucelus (STN) for PD and internal pallidum (GPi) for GD, CD and PD. Intracerebral electrodes were totally implanted into 187 nuclei. We evaluated stimulation parameters, while clinical response and parameters determined the accuracy of implantation. Results: The lowest effective amplitude of stimulation ranged from 0.3 to 2.5 V (median 1 V). The therapeutic interval ranged from 0 to 5 V (median 2.5 V). Tremor was eliminated in 92.9% of cases, rigidity in 94.7% and akinesia in 18.9%. The central trajectory was used for final electrode implantation in 56.7% of procedures. In STN the trajectory passed through the nucleus in the range of 3.5-7.5 mm (median 5mm). The difference of coordinates between expected and real position of electrodes was: Delta X = 0.5 (0-1.5), Delta Y = 0.7 (0-1.7), Delta Z = 0,5 (0-1.7). The most frequent side effects were paraesthesias (VIM 38%) and dysarthria (STN 28.3%). Overall morbidity occurred in 21% of patients. Conclusion: The results showed accurate targeting and optimal implantation technique with minimal morbidity.