Fri., 10/14/11 Pelvis & Spine, Paper #42, 10:17 am OTA-2011
The Clinical Efficacy of Compressive Transsacral Screw Fixation for Unstable Posterior Pelvic Ring Injuries
William Min, MD; Monique Chambers, BS; Michael P. Leslie, DO;
Mark A. Lee, MD; Tania A. Ferguson, MD;
University of California, Davis Medical Center, Sacramento, California, USA
Purpose: This study was undertaken to evaluate the use of compression via transsacral (TS) intramedullary screw fixation in the management of unstable posterior pelvic ring injuries. We hypothesized that our fixation protocol of anatomic reduction, compression, and TS screw fixation would improve stability of fixation, and that TS screw fixation would not cause detectable neurovascular injuries.
Methods: We reviewed a prospectively maintained, IRB-approved database of all patients treated with our fixation protocol between January 2006 and April 2010. Patients with less than 6 months of follow-up were excluded. Postoperative pelvic radiographs were assessed for radiographic healing, fixation failure, and loss of reduction at the immediate, 6-week, 3-month, and 6-month postoperative intervals. Medical records were reviewed for changes in the neurologic examination before and after surgical management of the pelvic ring injury.
Results: 50 patients treated with 55 TS screws met inclusion criteria. 35 (70.0%) of these patients had zone II sacral fractures, 19 (38.0%) had sacroiliac fracture/dislocations, and 4 (8.0%) had spinopelvic dissociation. 37 screws were placed through the S1 body, and 18 were placed through S2. Nine patients were documented to have preoperative nerve injuries, but none had new neurologic deficits after reduction and fixation. Two patients suffered postoperative displacements. One patient had a combined injury pattern demonstrating cranial displacement, flexion, and internal rotation through a zone II sacral fracture. Although the cranial reduction was maintained, flexion and internal rotation of 5° over a retrograde ramus screw was observed at the 6-week radiograph and the patient healed in this position. The second patient had spinopelvic dissociation with gluteal necrosis and massive soft-tissue injury. She was stabilized with anterior symphyseal plating, spinopelvic fixation, and TS fixation at S1. A severe infection developed requiring removal of spinopelvic fixation. The TS screw subsequently failed by pull-out, resulting in complete hemipelvic displacement and an infected sacral nonunion.
Conclusions: Anatomic compression and transsacral screw fixation provided excellent stability and maintenance of reduction in patients with unstable posterior pelvic ring injuries. Although the placement of an intramedullary screw traversing the sacrum inherently increases the risk of neurologic encroachment, we did not observe any iatrogenic neurologic deficits with TS screw placement. Furthermore, the compression of zone II sacral fractures was not associated with neurologic injury.
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• The FDA has not cleared this drug and/or medical device for the use described in this presentation (i.e., the drug or medical device is being discussed for an “off label” use). ◆FDA information not available at time of printing. Δ OTA Grant.