Template Guided Intervention: Interactive Visualization and Design for Medical Fused Deposition Models

Extended Abstract: We are combining surgical planning techniques with computer aided manufacturing systems to create custom surgical aids for orthopedic surgery. Our first application area is planning and controlling the trajectories of pedicle screws for spine surgery. The goal is to manufacture a physical jig that conforms to the contours of the patient’s vertebrae. The jig is constructed with holes that correspond to the trajectories of the pedicle screws. These holes guide the drill placement and depth, increasing the accuracy and precision of screw placement (Figure 1). These devices are created for each individual patient, one per segment, and improve accuracy without the introduction of navigation tools or increased fluoroscopic radiation dose. The intent is to use a jig to transfer the surgical plan directly to the operating room without introducing additional technology. Difficulties of computer assisted surgery remain in the laboratory without intruding into the operating room. We briefly describe our work in rapid prototyping for computer-assisted surgery. In this paper we address the design issues for the surgical planning and template design workstation. Our prototype is an interactive modified texture-based volume rendering program [2] augmented with physical user interface devices, 3D stereo viewing, polygonal primitives, and tools for constructive solid geometry (CSG) to serve as the computer aided design foundation for modeling templates.