Accuracy and safety of pedicle screws inserted with IGS guidance − The impact of IGS reference array position

Pedicle screw fixation was a commonly used method for stabilizing the spine and providing 3-column support. The emergence of image-guided surgery (IGS) has revolutionized spinal surgery, allowing surgeons to perform procedures with greater accuracy and safety. One of the key components of IGS systems is the use of reference arrays (RA) and image-based navigation to guide screw placement. The aim of this study was to investigate the relationship between pedicle screw placement accuracy and the distance from the IGS reference array. A total of 93 pedicle screws (18 cervical, 49 thoracic, and 26 lumbar) were inserted in 21 patients at Hospital XX between October 2017 and July 2022. The accuracy of screw placement was evaluated using post-operative CT scans. The screws were rated on the Gertzbein-Robbins (GR) classification scale, which assigned Grades 0–3 (Grade 0: Screw within pedicle, Grade 1: ≤2 mm breach, Grade 2: >2 – 4 mm breach, Grade 3: >4 mm breach). The pedicle screw placement was further divided into “Satisfactory Placement” (Grade 0–1) and “Unsatisfactory Placement” (Grade 2–3). The accuracy of screw placement was satisfactory (≤2 mm) in 80.6 % of all segments. The distance from the RA up to four segments did not significantly affect screw accuracy when using IGS guidance. Only one patient experienced a complication, which was a CSF leak likely due to a dural tear during pedicle screw fixation. The results suggested that the distance from the reference array did not significantly affect screw accuracy within the studied range (up to four segments). Therefore, for posterior spinal instrumentation within four segments from the reference array, re-scanning and re-registration may not be necessary, potentially reducing operative time.