S2 iliosacral screw fixation for disruptions of the posterior pelvic ring: A report of 49 cases

Objectives: The purpose of this study was to evaluate the clinical safety and efficacy of using S2 iliosacral screws for pelvic fracture fixation. Design: Retrospective analysis of a treatment protocol in a consecutive patient series. Setting: Level I trauma center. Patients: Between 1996 and 2001, 49 patients were treated with S2 iliosacral screws. There were 9 bilateral injuries with a total of 53 S2 screws inserted. Patients ranged in age from 14 to 71 years. Follow-up averaged 19 months (range 6 months to 6 years). Preoperative and postoperative radiographic evaluation included anteroposterior, inlet and outlet pelvic x-rays and two-dimensional computerized tomography (CT) with 3-mm slice thickness. Candidates for S2 screw fixation required adequate space on CT, which was defined as a minimum of I cm between foramina on 3 sequential preoperative CT slices in conjunction with inadequate available space in S1. Intervention: S2 iliosacral screw fixation of disruptions of the posterior pelvic ring. Main Outcome Measurements: Intraoperative iatrogenic nerve root injuries, postoperative screw position, and maintenance of the fixation construct under physiologic load. Results: There were no intraoperative iatrogenic nerve injuries. However, postoperative loss of reduction requiring revision surgery occurred in 2 patients with osteopenia. One was associated with injury to the S1 nerve root, which had full return of function within I year. Satisfactory screw position was documented on postoperative CT in all cases. Conclusions: S2 iliosacral screw fixation is a safe and effective technique. However, it should be used with caution in patients with suspected pelvic osteopenia. Furthermore, any S2 screw with questionable purchase should be removed and an alternative fixation method selected.