P07.03.A Advances in Robotic Navigated Laser Craniotomy. An in-vivo non-recovery animal study

Abstract

Abstract Background We previously described a new frameless stereotactic intervention using robotic guided laser beam for depth electrode placement. This study tested the feasibility of a new cutting strategy for angulated precision bone channels as well as improved cut-through detection using optical coherence tomography (OCT) and a new generation of co-axial live video feed. Material and Methods Preoperative CT scans were performed to plan trajectories for bone channels angulated 45, 60, and 90° relative to the surface. The animals were prepared under general anesthesia by a trained veterinarian conforming European requirements and Good Laboratory Practice regulations. A new cutting strategy was implemented consisting of two circular paths and three different ablation phases. After cut-through detection bolts and depth electrodes were inserted. Before termination ad-hoc planned laser craniotomies were performed to evaluate possible cortex damage. Results 70 robotic guided laser beam precision bone channels were cut in four pig specimens. Bolts and depth electrodes were implanted solely guided by the trajectory given by the laser precision channels. The new cutting strategy showed no irregularities for either cylindrical (n=38, 45°=10, 60°14, 90°=14) or anti-conical (n=33, 45°=11, 60°=13, 90°=9) bone channels. Angulation and hole diameter showed no significant difference between cylindrical and anti-conical cutting strategies. The updated co-axial camera live video feed in addition to OCT reliably detected cut-through in 80% of cases. Insertion of bolts with firm fit was achieved in 94% of bone channels. All four anesthesia protocols showed no irregularities. No unintended damage to the cortex was detected after laser guided craniotomy. Conclusion The new cutting strategy showed promising results in 70 precision bone channels for angulated cylindrical and anti-conical channels in a large in-vivo non-recovery animal study. OCT signal and a new co-axial camera proved its feasibility for cut-through detection. Robotic guided laser beam techniques proved its feasibility for the placement of depth electrodes and might be a suitable option to optimize the burr hole for biopsies.