Usefulness of a navigation system in surgery for scoliosis: segmental pedicle screw fixation in the treatment

Study design  Postoperative outcomes of segmental pedicle screw fixation were evaluated in posterior scoliosis surgery with the use of navigation system. Objectives  We report the usefulness of a navigation system and a segmental pedicle screw fixation in surgery for scoliosis. Summary of background data  Few reports on a segmental pedicle screw fixation method for scoliosis surgery using a navigation system have been published. This is the report on the usefulness of a navigation system in segmental pedicle screw fixation. Methods  We targeted 16 cases in which segmental pedicle screw fixation had been performed using a navigation system at our hospital. We inserted 264 pedicle screws in total, and we did not perform registration for each corpus vertebrate in order to shorten the duration of the surgery. We reviewed screw deviation among the items for review using Neo classification with postoperative CT images (1.25 mm). For screw deviation in this case, grade 2 or higher in the Neo classification system was designated as total deviation. Furthermore, we evaluated the registration period per corpus vertebrae, the complications, duration of surgery, blood loss, Cobb angle, and the correction rate. Results  In terms of screw deviation, 11 (4.2%) of the 264 inserted screws were classified as total deviation. However, there were no neurovascular complications during or after surgery in any cases, and all cases maintained strong internal fixation. In the relationship between the use or nonuse of registration and the deviation, four screws (3.2%) in the corpus vertebrae for which registration was performed and seven screws (5.0%) in the adjacent corpus vertebrae for which registration was not performed had deviated. The duration of registration per corpus vertebrate averaged 4 min and 24 s (58–791 s), but registration also requires a learning curve, so the duration of registration per corpus vertebrae averaged 1 min and 14 s in more recent cases, thus marking a significant shortening. Conclusion  Segmental pedicle screw fixation are excellent in regard to their fixing and correction force and have been clinically applied even in surgery for scoliosis, but the potential risk of neurovascular complications is unavoidable. The adoption of a navigation system in surgery for scoliosis is useful to increase the safety and certainty of the insertion of pedicle screws.