Application of patient-specific 3D navigation templates for pedicle screw fixation of subaxial and upper thoracic vertebrae

Abstract

Objective. To analyze the safety and accuracy of pedicle screw placement in the subaxial cervical and upper thoracic spine using patient- specific 3D navigation templates. Material and Methods. The study included 16 patients who underwent transpedicular implantation of screws in the subaxial cervical and upper thoracic vertebrae using patient-specific 3D navigation templates. A total of 88 screws were installed. All patients underwent preoperative CT angiography to assess visualization of the vertebral artery. Customized vertebral models and navigation templates were created using 3D printing technology. Models and templates were sterilized and used during surgery. The results of screw implantation, as well as the safety and accuracy of the placement, were assessed by postoperative CT. Results. The average deviation from the planned trajectory was 1.8 ± 0.9 mm. Deviation was estimated as class 1 (<2 mm) for 57 (64.77 %) screws, class 2 (2–4 mm) for 29 (32.95 %), and class 3 for two (2.27 %). The safety of screw implantation of grade 0 (the screw is completely inside the bone structure) was in 79 (89.77 %) cases, of grade 1 (<50 % of the screw diameter perforates the bone) – in 5 (5.68 %), and of grade 3 – in 2 (2.27 %). Conclusion. Using 3D navigation templates is an affordable and safe method of installing pedicle screws in the cervical and upper thoracic spine. The method can be used as an alternative to intraoperative CT navigation.

Keywords

• 3d printing
• navigation
• transpedicular fixation
• template