A Neurosurgical Robotic System for Minimally Invasive Spinal Fusion of Osteoporotic Vertebrae Using Flexible Pedicle Screws

摘要/摘要： 我们的长期目标是开发一种新型的半自主、微创、图像引导的神经外科手术 机器人工作站，由机器人定位机构、连续体机械手组成，灵活 器械和柔性植入物(即柔性椎弓根螺钉(FPS))，以使下一代最低限度- 以及侵入性较小的脊柱介入治疗。通过提供对椎体内区域的访问，这些区域目前是 这种神经外科机器人工作站无法使用传统的刚性手术器械进行操作，它将使 脊柱各种骨缺损的外科治疗，如脊髓和/或神经根受压， 转移性骨病，以及严重骨质疏松症引起的椎体压缩骨折。对于这个项目，我们 主要将侧重于机械设计、开发、基本控制和评估的子系统 这一新型机器人系统的目标是对骨质疏松椎体进行微创脊柱融合。 大约5400万50岁及以上的美国人患有骨质疏松症，估计造成200万人 每年仅在美国发生骨折。椎体骨折是骨质疏松性骨折中最常见的一种 (约47%)，这会导致背痛、身高下降，以及进一步的脊椎和非脊椎骨折。失败 的非手术治疗经常导致脊柱融合手术，以恢复脊柱的稳定性使用刚性 椎弓根螺钉(RPS)。然而，解剖学上的限制和器械和螺钉的刚性迫使 外科医生通常在椎骨的低骨密度(BMD)区域内植入螺钉 骨质疏松的脊椎。这会增加螺丝钉松动、拔出以及随后手术的风险。 失败了。 我们的中心假设是，利用所提出的微创机器人系统， 与RPSS的脊柱融合可以显著改善。这一改进将通过(I)开发一种 基于椎骨空间(3D)骨密度规划曲线钻进轨迹的生物力学分析模块 通过QCT扫描获得；(Ii)增加外科医生的可达性，使他们能够在高骨密度下进行钻探 使用可导向钻探机器人和曲线钻探技术对脊椎区域进行钻探；(Iii)选择性地 将FPS植入/锚定在高BMD区域内的预先计划的钻孔弯曲轨迹内， 可提高融合的拔出强度和稳定性；(4)FPS融合的生物力学分析 和/或骨水泥，以优化脊柱稳定性，防止椎体塌陷，并需要进行翻修手术。 建议的贡献是重大的、高影响的和创新的，因为它提供了消除 通过提出新的和创新的技术来解决当前脊柱融合手术的上述并发症。至 我们的知识，利用可导向的钻井机器人和FPS的机器人辅助技术还没有 为骨质疏松椎体的微创脊柱融合术而开发。我们的目标是证明 所提出的系统可以显著改善目前对骨质疏松椎体的治疗，并将目前的 临床范例。

Summary/Abstract: Our long-range goal is to develop a novel semi-autonomous, minimally-invasive, image-guided neurosurgical robotic workstation that consists of a robotic positioning mechanism, a continuum manipulator, flexible instruments, and flexible implants (i.e., flexible pedicle screws (FPSs)) to enable the next generation of minimally- and less-invasive spinal interventions. By providing access to regions within vertebral body, which currently are not accessible utilizing conventional rigid surgical instruments, this neurosurgical robotic workstation will enable surgical treatment of 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. For this project, we mainly will focus on the mechanical design, development, basic control, and assessment of the subsystems of this novel robotic system with the goal of minimally invasive spinal fusion of osteoporotic vertebrae. Approximately 54 million Americans age 50 and older have osteoporosis causing an estimated two million broken bones per year in the US only. Vertebral fractures are the most common type of osteoporotic fractures (about 47%), which can lead to back pain, loss of height, and further vertebral and non-vertebral fractures. Failure of non-surgical treatments often leads to a spinal fusion surgery to restore stability of the spine using Rigid Pedicle Screws (RPSs). However, anatomical constraints and rigidity of instruments and screws force the surgeon to typically implant the screw inside the low bone mineral density (BMD) regions of the vertebrae in an osteoporotic spine. This results in an increased risk of screws loosening, pullout, and subsequently a surgical failure. It is our central hypothesis that utilizing the proposed minimally-invasive robotic system, the success rate of spinal fusions with RPSs can be significantly improved. This improvement will happen by (i) developing a biomechanical analysis module to plan a curved drilling trajectory based on the spatial (3D) BMD in the vertebra obtained by QCT scans; (ii) increasing the reachability of the surgeons and enabling them to drill in high-BMD regions of vertebra using a steerable drilling robot and the curved-drilling technique; (iii) selectively implanting/anchoring the FPSs within the pre-planned drilled curved trajectories inside the high-BMD regions, which can improve the pullout strength and stability of fusion; (iv) Biomechanical analysis of the fusion with FPS and/or bone cemnet to optimize the spine stability, prevent vertebral collapse, and a need for revision surgery. The proposed contribution is significant, high impact, and innovative since it offers to eliminate the aforementioned complications of current spinal fusion surgery by proposing novel and innovative techniques. To our knowledge, robotically-assisted techniques utilizing a steerable drilling robot and FPSs have not been developed for a minimally invasive spinal fusion of osteoporotic vertebrae. Our goal is to demonstrate that the proposed system can significantly improve the current treatment of osteoporotic vertebrae and shift the current clinical paradigm.