Computer-Aided Design and Manufacturing for Digital Orthopedics
Over the past decades, the surgical guides or templates as the high-precision technologic tools have been applied for various surgeries such as the oral implantology, oncology, nasal prosthesis implant placement, cervical or lumbar pedicle screw placement, total hip arthroplasty (THA), treatment of sacroiliac joint fracture, total knee arthroplasty (TKA), etc. The surgical template is a guide aiming at directing the drilling, osteotomy, or tumor resection, providing an accurate placement of the implant or prosthesis, etc. Therefore, with the use of it, the preoperative planning can be transferred to the actual surgical site, and the precision and safety and reliability of the surgery can be improved. The general workflow of the template design and manufacturing (shown in Fig. 5.1) is described as follows: on the basis of the original medical image data (computed tomography (CT), cone beam computed tomography (CBCT), magnetic resonance imaging (MRI), etc.), image processing (including segmentation and registration) is conducted through the preoperative planning software. Then, modeling of the critical anatomical structures is realized for 3D visualization. Based on the series of 2D images (coronal, sagittal, and axial) and the 3D-reconstructed models, preoperative planning is performed, including 2D/3D geometrical measurements, the optimization design of the position and orientation of surgical trajectory, the simulation of implant placement, etc. According to the result of preoperative planning, the surgical template can be designed using key technologies of reverse engineering, point cloud, and surface reconstruction. Then, it can be fabricated through numerical control machining, additive manufacturing (3D printing) technologies, etc., and the clinical application can be finally conducted.