Fluoroscopic positioning of sacroiliac screws in 88 patients

Background: Fluoroscopic placement of guided sacroiliac screws is a well-established method of fixation of the posterior pelvic ring, leading to biomechanical results similar to an intact pelvic ring. The main problem remains the risk of neurologic injury resulting from the penetration of the intervertebral root or the vertebral canal. Methods: Eighty-eight patients in whom the posterior pelvic ring was stabilized for several indications were reviewed retrospectively. On perioperative and direct postoperative radiographs and postoperative computed tomographic (CT) scans, positioning was scored for 285 screws and compared with clinical results. Results: Depending on the type of imaging (radiography or CT scan), only 2.1% to 6.8% of the screws showed malpositioning. In several cases, the malpositioned screws did not cause any complaints. Postoperative radiographs did not show any additional value above perioperative radiographs in predicting malpositioning. Seven of 88 patients had neurologic complaints and underwent reoperation. All complaints resolved completely, and no permanent neurologic damage occurred. Positioning both sacroiliac screws in the first vertebral body had a significantly lower rate of neurologic complaints compared with the lower screw in the second vertebral body. CT scanning was able to predict neurologic complaints most accurately. Conclusion: Percutaneous sacroiliac screws can be positioned safely, in experienced hands, using perioperative fluoroscopic techniques. A position in the first vertebral body had a significantly lower incidence of neurologic injury compared with a position in the second. In case of postoperative neurologic deficit, only CT scan can predict the clinical outcome. Further research toward improving the perioperative imaging technique must be undertaken.