Stimulation of globus pallidus

Abstract

In recent years, the subthalamic nucleus (STN)and globus pallidus internus (GPi) have been targeted with deep brain stimulation (DBS) for the treatment of Parkinson’s disease (PD). Because there are unique clinical effects associated with DBS treatment in each target, the target should be selected depending on an individual patient’s symptoms. Here, we provide a detailed introduction to our surgical method of GPi-DBS. In order for DBS to be maximally effective, the most important part of the procedure is optimal electrode positioning at the target. To do so, each step of the surgery, including stereotactic head frame placement, target coordinate determination, microelectrode recordings (MERs), and macrostimulation should be accurately performed. To reduce the risk of placement error, it is important to position the stereotactic frame with its axes orthogonal to the standard anatomic planes of the brain. During stereotactic surgical procedures, there are two possible approaches for locating the target: Indirect targeting, aiming at a target with coordinates relative to anatomical landmarks, or direct targeting, aiming at a visible target with absolute coordinates using the stereotactic space of the frame as a reference. Image-guided stereotactic procedures alone are not adequate for placing a DBS lead; physiological studies are also important for confirming final placement. We routinely use MERs and macrostimulation for physiological confirmation. The electrode track location is estimated by measuring the length of the area where high-frequency discharges are recorded. Macrostimulation is the most useful tool during GPi targeting because it can confirm if the location is the so-called.