ロボット支援下椎弓根スクリュー設置のための3Dプリントガイドテンプレートを用いた新規無放射ナビゲーション法：死体解剖学的研究

Robot-assisted spinal surgery has advanced surgical accuracy but increased radiation exposure for both staff and patients, raising safety concerns. The purpose of this study was to evaluate the clinical accuracy of thoracic pedicle screw placement performed with a 3D-printed navigation guide plate for robotic registration and to determine whether equivalent precision can be achieved without intraoperative imaging.

Seven fresh-frozen human cadaveric torsos underwent preoperative CT of the thoracic spine. Reverse-engineering principles were used to design patient-specific 3D-printed navigation guide plates that were recognized by the robot's binocular vision system (XGK-6508A). After automatic guide-pin insertion, 168 thoracic pedicle screws (T1-T12 bilaterally) were implanted. Postoperative CT assessed accuracy against preoperative planning using the Gertzbein-Robbins scale (GRS), deviation distance (DD, mm), and deviation angle (DA, °). Implantation time per screw was recorded.

98% of screws met acceptable GRS grades (Grade A 85%, Grade B 13%). Mean DD at entry and exit points was 0.4 ± 0.3 mm and 0.5 ± 0.3 mm in the sagittal plane and 0.3 ± 0.2 mm and 0.4 ± 0.2 mm in the axial plane, respectively. Mean DA was 3.2 ± 2.0 ° sagittally and 2.4 ± 4.5 ° axially. The mean implantation time per screw was 2.4 ± 1.7 min. Average insertion time decreased from 8.0 ± 4.5 min per screw in the first three cadavers (72 screws) to 1.8 ± 2.2 min in the last four (96 screws) (p = 0.012).

3D-printed navigation guide plates enable accurate, radiation-free robot-assisted thoracic pedicle screw placement. Surgical efficiency improved markedly with experience, supporting the technique as a safe alternative to conventional image-guided methods. This study involves no ionizing radiation in its methodology and transforms the traditional registration process for robots, making it safe and efficient.