COMPUTED AIDED DESIGN OF 3D TEMPLATE FOR PEDICLE SCREW TRAJECTORY IN THORACIC VERTEBRAE

ABSTRACT Pedicle screw fixation is one of the commonly employed orthopedic surgeries due to its enhanced biomechanical advantages. However, this method is limited by the accurate placement of the screw which is often dependent on the technical expertise of the surgeon. In addition, improper fixation of the pedicle screw often results in vascular, neurological, and visceral injuries. Hence, there is a need to simulate the pedicle screw fixation preoperatively. In this study, a pedicle screw template is developed in the thoracic vertebrae (T12 region) to assess the accurate placement using CT images. The T12 region is segmented from the CT images using Materialize MIMICS innovation suite (v21.0). Using AutoCAD, the 3D pedicle screw is developed for the segmented T12 vertebrae. The simulated CAD model pedicle screw is then imported into MIMICS software and the fitting of the pedicle screw into the lamina region is evaluated. In addition, a pedicle screw navigation template is developed for the T12 thoracic vertebrae. The pedicle screw diameter and length are determined as 7 mm and 38 mm. The fitting of the developed pedicle screw model into the lamina region is evaluated and the simulation of screw insertion is assessed using MIMICS software. By this method, it is possible to measure accurate pedicle screw length and diameter from preoperative or intraoperative CT scans in real-time, thereby we can customize the pedicle screw navigation template based on the subject’s anatomical preference. Thus, this study aid in less neurovascular complications increased placement accuracy, and reduced plan time. Keywords: Pedicle screw fixation, Thoracic vertebrae, MIMICS, T12 region, AutoCAD