Deep brain stimulation in dystonia: sonographic monitoring of electrode placement into the globus pallidus internus.

Deep brain stimulation (DBS) of the globus pallidus internus (GPi) is an effective treatment in primary dystonia. Its success depends on the implantation accuracy of the DBS electrode into the targeted GPi. Discrepancies of up to 4 mm between the initial target, selected on preoperative MRI, and the final DBS lead location are caused mainly by caudal brain shift that occurs once the cranium is open. Nowadays, transcranial sonography (TCS) can display echogenic deep brain structures with higher image resolution compared to MRI under clinical conditions. Here, we demonstrate for the first time the use of a contemporary clinical high-end TCS system for intraoperative monitoring of DBS electrode position. Herewith, a high-resolution real-time imaging of closely located microelectrodes and of the DBS lead through the intact skull is feasible. Simultaneous color-coded sonographic imaging of arteries near the anatomical target allows further intraoperative refinement of DBS lead positioning, simultaneously preventing hemorrhages.