Introduction. Percutaneous pedicle screws (PPSs) are commonly used in posterior spinal fusion to treat spine conditions such as trauma, tumors, and degenerative diseases. Precise PPS placement is essential in preventing neurological complications and improving patient outcomes. Recent studies have suggested that intraoperative computed tomography (CT) navigation can reduce the dependence on extensive surgical expertise for achieving accurate PPS placement. However, more comprehensive documentation is needed regarding the procedural accuracy of lateral spine surgery (LSS).
Methods. This retrospective analysis reviewed cases of patients who received PPS via the LSS technique, assisted by intraoperative CT navigation, from April 2019 to September 2023. The study included 170 patients (151 undergoing lateral lumbar interbody fusion [LLIF] and 19 trauma cases), amounting to 836 PPS placements. Data were collected from medical records, focusing on PPS characteristics (using the (Ravi scale grades [Grade I: no deviation, Grade II: <2 mm, Grade III: 2–4 mm, Grade IV: >4 mm]) and the direction of PPS misplacement. Additionally, the study employed the Zdichavsky classification to assess pedicle screw positioning, with six distinct patterns ranging from 1a to 3b. There was no abnormality in screw insertion: 1a.
Results. The overall PPS deviation rate was 2.5%, with deviations more prevalent in the thoracic spine (7.4%) than in the lumbar spine (1.9%). Deviation rates for PPS placements directed upside or downside did not differ significantly. Perioperative complications related to intraoperative CT navigation occurred in three patients. In the thoracic spine, two patients exhibited 2b inner position deviations (two screws), at T7 and T12. In the lumbar spine, deviations were noted in two patients (three screws), one at L3 and two at L5. There were no 3b inner position abnormalities in the lumbar spine, whereas two patients (three screws) in the thoracic spine showed such abnormalities—one at T6 and two at T11. The most frequent deviation pattern was type 1b, with 9 screws in total (1.1%).1b is a pattern in which a screw is inserted into the vertebral body from outside the pedicle.
Discussion. In conclusion, this retrospective study sheds light on the challenges associated with achieving precise PPS placement in the lateral decubitus position, with a significantly higher deviation rate observed in the thoracic spine compared to the lumbar spine. This study emphasizes the need for ongoing research to improve PPS insertion techniques, leading to enhanced patient outcomes in spine surgery.