Can Sacropelvic Fixation Improve Outcome of Long-Segment Lumbar Spine Fusion in Patients with Degenerative Lumbar Spine Disease?

Background Data: Posterior spinal fusion has been more and more used for management of degenerative disorders of the lumbosacral spine. Long-segment fixation of three or more motion segments extending down to the sacrum has been associated with loosening or failure of S1 screws. Purpose: Comparison between fixations extending to S1 and those to S2 (S2-alar-iliac screws) with sacropelvic fixation in the management of multilevel lumbar spinal canal stenosis. Study Design: Prospective controlled cohort study. Patients and Methods: We recruited 45 patients suffering from lumbar spinal canal stenosis of 3 or more levels including 16 revision cases in the whole group. In 23 patients, posterior lumbar fusion extended to S1 and in 22 fixations extended to S2. Preand postoperative clinical evaluation included Visual Analogue Scale (VAS) for back pain and Oswestry Disability Index (ODI). Preoperative radiological evaluation included plain X-ray and MRI. Postoperative clinical evaluation included VAS and ODI and radiological evaluation included X-ray and CT. The mean follow-up duration was 14.1±1.7 months (range, 12–24) in S1 group and 14.3±1.9 months (range, 12–24) in S2 group. Results: The mean VAS improved from 8.1±0.8 to 4.9±0.9 in S1 group and from 7.7±1.2 to 1.95±0.79 in S2 group. The mean ODI improved from 77±10.5 and 76.8±10.9 to 45.9±7.3 and 29.5±8.4 in S1 and S2 groups, respectively. Two dural tears were repaired intraoperatively with no postoperative consequences. Seven cases in S1 group had loosening of S1 screw that was evident at 6-month follow-up. Conclusion: Sacropelvic fixation in the form of S2-alar-iliac screws provides a significantly more rigid construct, decreasing the incidence of loosening of S1 screws and improving the overall outcome in patients treated with long lumbar fusion. (2019ESJ199)