410 A Novel Robotic-Enabled MIS System for Patient-Specific Spinal Fixation in High Risk Bone Density

INTRODUCTION: Spinal fixation for patients with osteoporotic or tumor-weakened vertebrae require targeting patient-specific areas of strength to reinforce and reduce failure risk. Current approaches for these high-risk patients often fail due to poor fixation forces of rigid pedicle screws. We report using flexible robotic tools to create curvilinear screw trajectories as a novel minimally-invasive system, providing a personalized patient-specific approach. METHODS: A structured framework facilitates information exchange between surgeon and robot for a patient-specific image-guided approach. The framework starts with pre-operative quantitative CT scans with which the surgeon can identify high bone mineral density (BMD) areas suitable for implant placement. This then guides the robotic system in creating arbitrary curvilinear pathways for implant insertion, ensuring stronger fixation. RESULTS: The framework was validated through testing on phantom vertebrae and bovine samples. In simulated testing on high-resolution CT obtained from an osteoporotic patient’s lumbar vertebra, Finite Element (FE) analysis of axial loading revealed a decrease of 80.1% of stress and 77.5% of strain with our system compared to standard pedicle screws. In a bovine bone model, drilling forces during insertion saw a maximum of 3.04 N, well within validated safe ranges for human pedicles. The drilling and implant system together demonstrated errors less than 1 mm in radius when placing flexible implants in sawbone phantom models, in both axial and sagittal planes. CONCLUSIONS: By employing a robotic-enabled and patient-specific approach to spinal fixation, utilizing curvilinear drilling trajectories and flexible implants to target high-density regions, we open up the potential for a new paradigm in spinal fixation for high-risk vertebrae, such as in osteoporosis or tumor.