A Percutaneous Spinal Surgical Procedure Using a Biplanar Fluoroscopy-Guided Robot System

초록

Most of medical robot systems have been applied to the laparoscopic operations, orthopedic operations, and brain surgery areas. There are only a few practical cases reported on the use of the robot system for spinal surgery in literature up to now. Most of current spinal surgical procedures at hospitals rely on surgeon’s experience only with aid of fluoroscopy, computer tomography (CT), or magnetic resonance images (MRI) yet in open spinal surgery. Pedicle screw instrumentation is widely used in the lumbar spine as a means of stabilization of degenerative spinal disease. Indications for pedicle screw insertion include stabilization in the setting of trauma, deformity, and reconstruction. Main problem is the risk of iatrogenic injury due to mal-positioning of the pedicle screws. In the lumbar spine, Castro, et. Al [1996] reported a pedicle violation rate of 29%. Odgers, et al [1996] reported underplacement of 239 pedicle screws from T11 to L5 and observed a pedicle wall penetration rate of 10%, of which 18 were medially and 6 were laterally. Thus, it is required to develop a safe guide system like a robot to assist the percutaneous pedicle screw instrumentation. This work proposes a percutaneous spinal surgical procedure. A bi-planar fluoroscopy and a surgical robotic system were developed to conduct a fluoroscopy-guided surgery for spinal fusion. The surgical planning is prepared by a surgeon through analysis of the bi-planar fluoroscopic image. The major role of the system is to assist a surgeon for inserting a pedicle screw in spinal fusion. The self-made bi-planar fluoroscopy is used as a reference coordinate to which the robot position and the target position are initialized. During operation, it provides the surgeon with real time intra-operative images. A surgical robotic system that is composed of a 5-DOF SCARA type manipulator and an automatic bed was developed. Thebi-planar fluoroscopy, the robotic system, and motion planning algorithm are integrated to perform a phantom and a cadaver experiment. Compared to pure navigation systems as well as conventional methods for spinal fusion, the developed fluoroscopy-guided robotic system is able to achieve better accuracy through compensating for the portending movement of the surgical area.