Innovative Design and Validation of Patient-Specific Instruments for Enhanced Trajectory Precision in Posterior Spinal Fusion Surgery

he pedicular screw fixation became popular in Europe by Roy-Camille in 1970 by using posterior plates and screws. Gertzbein et al. studied the accuracy of the 167 screw placements in 1989 from T8 to S1 level. The survey was shown that 81.5% of the screws were inserted with 2 (mm) or less intrusion beyond the medial board of the pedicle. In 1996, Amiot et al. performed a case-control study on pedicle screw implantation, comparing a group that used computer-assisted pedicle screw insertion with a conventional surgery group. The results showed a 15% error rate from T5 to S1 in the conventional surgery group and a 5% error rate from T2 to S1 in the computer-assisted surgery group. Cleynenbreugel et al., in 2002, validated transarticular fixation at the C1-C2 spinal level using personalized drill guides manufactured from acrylate resin by stereolithography. In 2018, research was carried out on the stability of the posterior spinal guide on cadaveric vertebrae, adding a teleoperation system to achieve appropriate fixation and ensure good stability. In 2021, Athari et al. studied the fusion of the first and second cervical vertebrae using pre-fabricated guides on cadaver samples. Despite advancements in pedicle screw fixation techniques, challenges remain, particularly regarding the accuracy of screw placement and the associated risk of complications. Previous studies have highlighted limitations in free-hand insertion methods and variations in the precision of conventional and computer- assisted techniques. This study aims to address these limitations by evaluating the efficacy of a preoperative planning guide in improving the accuracy of pedicle screw placement.