A Biomechanics-aware Image-guided Surgical Robotic Framework For Spatial Spinal Fixation Using a Steerable Drilling Robot and Flexible Pedicle Screws

About This Grant

Summary/Abstract: Our goal is to develop a novel semi/autonomous, minimally-invasive, image-guided neurosurgical robotic workstation that consists of (i) a biomechanics-aware design and planning module, (ii) a robotic positioning mechanism integrated with a unique sensorized steerable drilling robot, and (iii) a novel flexible pedicle screw (FPS) to enable the next generation of minimally invasive spinal fixation interventions. In this workstation, a surgeon first uses Quantitative Computed Tomography (QCT) scans of a patient to map spatial bone mineral density of the vertebra and perform pre-operative biomechanical analysis and surgical planning. Next, they can intuitively and accurately control the developed steerable drilling robotic system via an autonomous or semi- autonomous mode to execute this plan in real-time and implant flexible pedicle screws in the drilled tunnels. By providing spatial access to the regions within vertebral body, which are not currently accessible utilizing conventional rigid surgical instruments, this neurosurgical robotic workstation enables the next generation of spinal fixation called Spatial Spinal Fixation (SSF) for various bone defects in spine such as compression on the spinal cord and/or nerve roots, metastatic bone disease, and vertebral compression fractures due to severe osteoporosis. Spinal fixation (SF) is one of the standard procedures performed by the spine and orthopedic surgeons. SF is an effective treatment option for a wide range of spinal disorders such as stabilization of vertebral compression fractures, scoliosis, and disk disease. Since the 1990s, rates of SF procedures in the United States have substantially increased. For example, over 500,000 SF operations were performed in 2018 in the US, with a mean patient age of 54.2 years and a mean cost of $27K-$78K per operation (totaling $13B-$40B/year). Pedicle Screw (PS) Fixation is the gold-standard of internal spinal fixations. However, anatomical constraints and rigidity of instruments and PSs force the surgeon to typically implant the screw inside the low bone mineral density (BMD) regions of the vertebrae particularly in an osteoporotic spine. These constraints result in an increased risk of screws loosening, pullout, and subsequently a surgical failure. It is our central hypothesis that utilizing the proposed FPS in J-shape drilling tunnels, the success rate of spinal fixation procedures can be significantly improved. This improvement will happen by (i) exploiting the natural geometry of the vertebra, (2) significantly reducing the maximum stresses and strains on the bone, (3) dramatically minimizing the risk for screw loosening by distributing the exerted external loads along a continuous surface of the FPS, and (4) eliminating the risk of screw misplacement. The proposed contribution is significant, high impact, and innovative and our goal is to demonstrate that SSF procedure can significantly improve the current treatment procedures and shift the current clinical paradigm.