A new instrument for DBS surgery
Deep Brain Stimulation (DBS) is the electric stimulation of regions in the brain via an implanted lead wire with a distal exposed electrode. It is generally used as an adjustable and reversible treatment for various neurophysiological motoric, stroke and tremor disorders like Parkinson’s disease, epilepsy and dystonia. The stimulation pulses are supplied to the lead wire by an implantable pulse generator (IPG), which is implanted typically in the region under the patient’s clavicle.
A new MRI-compatible surgical instrument has been realized to replace the currently used stereotactic Leksell frame. Aim of the new instrument is to increase the positioning accuracy of the electrode and thereby increase the treatment’s efficacy. Furthermore, a reduction in surgery time is expected from 5 to 6 hours down to 1 to 2 hours.
Implantation is carried out after a shortened and optimized MRI-based trajectory planning procedure. For this, an adapter disc is fixated to the back of the patient’s skull with three bone screws. The disc provides a kinematic coupling between the skull and the instrument and also between the skull and a dedicated adapter platform on the MRI table. This way, the positioning of the head in the scanner is unambiguous and the scanner’s coordinate system can be used directly for targeting purposes with the adapter disc serving as origin. The stimulation target and entry point coordinates are translated to instrument settings via an algorithm based on the instruments kinematics.
MRI-compatibility is guaranteed as the complete instrument is realized from PEEK. This includes the motorization of the electrode insertion drive, which operates as a pneumatic mechanical stepping motor.