Experimental Investigation of Biomechanical Properties Influencing Electrode Deviation in Deep Brain Stimulation*

Parkinson's disease, a debilitating neurodegenerative disorder, is often treated with Deep Brain Stimulation (DBS) surgery, which requires precise electrode placement in specific brain regions for optimal outcomes. Understanding probe-tissue interaction during DBS is critical, especially because the brain is a highly non-homogeneous medium, presenting a significant challenge. To address this challenge, our study investigates factors influencing electrode deviation, focusing on the radiofrequency (RF) probe used in DBS surgery and the fluid-structure interaction (FSI) between the electrode and a multilayer agar gel model. The RF probe was initially inserted into the multilayer gel block, followed by the electrode after the RF probe's removal. Various gel interface angles and concentration gradients were systematically adjusted to study their effects. Mechanical properties of the gels were characterized using magnetic resonance elastography (MRE). High-speed imaging captured the dynamics of the probe channel's opening and closing, and the electrode's deflection relative to the target area. Our findings highlight the significant impact of gel interface angles on electrode deflection, identifying them as the most critical factor affecting precision. This research lays the groundwork for future studies involving actual brain tissue and aims to enhance the precision of DBS surgery, ultimately improving patient outcomes.