Session V - Pelvis


Fri., 10/8/04 Spine & Pelvis, Paper #30, 5:07 pm

·Radiographic and Functional Outcome of Vertically Unstable Transforaminal Sacral Fractures Treated with Spinal-Pelvic (Lumbo-Pelvic) Fixation

Henry Claude Sagi, MD (n); Eric Lindvall, DO (n);
Florida Orthopaedic Institute and Tampa General Hospital,
Tampa, Florida, USA

Purpose: We compared the efficacy of spinal pelvic fixation with the use of iliosacral screws alone in maintaining reduction of vertically unstable pelvic fractures associated with transforaminal sacral fractures. We report on the one-year functional outcome of patients treated with spinal pelvic fixation for vertically unstable transforaminal sacral fractures. We also report on a standardized method for assessing maintenance of reduction on pelvic follow-up radiographs.

Methods: Thirty patients with vertically unstable pelvic injuries associated with transforaminal sacral fractures were treated with spinal-pelvic (lumbo-pelvic) fixation. No fusions were performed. Patients were kept with touch-down weightbearing for 3 months. Follow-up was monthly for the first 3 months, then every 3 months until 1 year. Maintenance of reduction was assessed by a new standardized measurement method that used serial anteroposterior, inlet, and outlet views of the pelvis that minimized the error induced with changes in magnification and angle on follow-up radiographs. A historical cohort of 10 patients with vertically unstable transforaminal sacral fractures treated with iliosacral screws alone was retrospectively reviewed and assessed with the same standardized method for comparison. Functional outcome was assessed with version 2 of the Short-Form 36 (SF-36) and short version of the Musculoskeletal Function Assessment (MFA) questionnaires.

Results: Fourteen of the 30 patients had minimum 1-year follow-up. The average age was 32 years. Two patients had bilateral type-2 sacral fractures and four patients had contralateral sacroiliac joint dislocations. The average time from admission to surgery was 8 days. Six patients had massive de-gloving posteriorly. Three patients had iatrogenic nerve injury, two S1 and one L5, all of which resolved. There were two delayed unions (incomplete healing on CT scan after 6 months) and one infection requiring operative debridement. One patient had wound dehiscence treated with nonoperative
wound care that healed uneventfully. The average shift in position of the hemipelvis was 1% for outlet (range, 0% to 12%) and 0% for inlet (range, 0% to 7%). This result was significantly better (P <0.05) than that of the 10 patients treated with iliosacral screws alone, who had average changes of 15% for outlet (range, 5% to 28%) and 12% for inlet (range, 6% to 24%). Failure was considered a shift of more than 10% at final follow-up. There were four (40%) failures in patients with iliosacral screws, and one (7%) in a patient with spinal-pelvic fixation. Of the 14 patients, 8 have returned to their previous level of function; 3 are unhappy with their results. Functional outcomes based on SF-36 and MFA scores showed that the majority of patients continue to have low-back pain and functional disability compared with the population mean. All but four patients complained of painful and prominent fixation. Nine patients underwent removal of implants, and all nine reported relief of some of their posterior pelvic pain and increased mobility. There was no loss of reduction in any patient after removal of implants. However, mean SF-36 scores were not statistically different between those who underwent removal and those that did not. In addition, of those who underwent removal, SF-36 physical component scores did not change significantly after removal, but the mental component score improved significantly.

Conclusions/Significance: Spinal-pelvic constructs provide improved fixation for maintaining reduction of vertically unstable transforaminal sacral fractures when compared with iliosacral screws alone. A significant number of patients have chronic pain and disability despite near-anatomic reductions. This outcome may be because of fixation interfering with normal sacroiliac and lumbosacral motion, or hardware prominence. This discomfort can be diminished by removal of the implants without risk of loss of reduction. We recommend routine fixation removal after 6 months (if the fracture is healed) to allow both sacroiliac and lumbosacral motion to resume. The standardized radiographic assessment method is a useful tool to help follow maintenance of reduction on serial pelvic radiographs.