Abstract

Deep brain stimulation (DBS) is an universally accepted therapy for medically refractory Parkinson’s disease (PD). Both globus pallidus internus (GPi) and subthalamic nucleus (STN) stimulation are effective in improving the symptoms of PD and reducing dyskinesias. STN DBS is the most commonly performed operation for PD as compared to GPi DBS. Ventral intermediate nucleus (Vim) DBS is used occasionally in selected cases as an alternative for tremor predominant PD patients.

Patient selection is very much essential in achieving good outcomes. Good response to levodopa challenge is most important predictor of favourable long-term outcomes. The DBS surgery is typically performed in an awake state and involves stereotactic frame application, CT/MRI imaging, anatomical targeting, electrophysiological confirmation and intra-operative clinical monitoring for efficacy and adverse effects after intra-operative stimulation and implantation of the DBS lead and pulse generator.

Anatomical targeting consists of direct visualization of the target and anterior and posterior commissure in MR images, reformatting with stereotactic atlases, CT-MRI fusion, getting the entry point and trajectory from the computer-based software and accordingly getting the frame co-ordinates.

Physiological verification is achieved by microelectrode recording followed by implantation of the DBS lead and intraoperative test stimulation to assess benefits and side effects. The various aspects of DBS surgery will be discussed.

Keywords: Deep brain stimulation (DBS); Parkinson’s disease(PD); Stereotaxy