Radiographic and Clinical Results of Freehand S2 Alar-Iliac Screw Placement for Spinopelvic Fixation An Analysis of 45 Consecutive Screws

Study Design: This was a retrospective clinical case series. Objective: The purpose of this study was to evaluate mid-term outcomes of S2 ala-iliac (S2AI) screw fixation in patients who underwent multilevel posterior spinal fusion surgery. Summary of Background Data: There have been few reports on radiographic and clinical outcomes in patients who underwent spinopelvic reconstruction surgery using S2AI screw installation. Materials and Methods: Twenty-three patients were treated by a single spinal surgeon between September 2013 and June 2014 utilizing segmental instrumentation with pedicle and S2AI screw. Instrumentation including S2AI screw was performed by a freehand technique. Surgical, radiographic, clinical outcomes and complications were evaluated to determine surgical results of S2AI screw fixation. Results: The mean follow-up period was 16.9 months (ranged, 13-22 mo). The average number of fusion levels was 7.9 vertebral bodies. There were no cases of neurological deficit and violation of acetabulum or sciatic notch. A peri-screw halo was found in 1 patient and cortical wall violation was observed in 4 patients. The number of lateral and medial breaches was 2 and 3, respectively. All of them were asymptomatic. One patient experienced sacroiliac joint pain after S2AI screw installation. There was no case of screw/rod fracture and revision surgery for S2AI screw. Conclusions: Radiographic and clinical outcomes of freehand S2AI screw fixation was acceptable. Sacroiliac joint irritation symptoms after S2AI screw fixation were rare. S2AI screw instrumentation can be a good alternative for spinopelvic fixation.