Percutaneous Fluoroscopically Guided Lag Screw Fixation for Sacroiliac Luxation

Introduction: Sacroiliac luxation (SIL) is the traumatic separation of the wing of the ilium from the sacrum. The purpose of this study is to describe the surgical technique and evaluate the accuracy of lag screw fixation for SIL in dogs utilizing a novel fluoroscopically assisted percutaneous MIO technique. We hypothesize that this technique will achieve similar results to previously documented MIO techniques with low radiation exposure to personnel.

Materials and Methods: 17 beagles with iatrogenic SIL underwent reduction and stabilization with 3.5 mm screws. 14 G hypodermic needles and fluoroscopy were used to orient 2 K-wires for temporary stabilization and to guide drilling of glide and pilot holes using cannulated drill bits. Surgeons were able to step away during aiming, after initial reduction, and K-wire stabilization. Surgical time and radiation exposure were recorded. Postoperative CTs were performed to assess screw angulation and purchase.

Results: The average time for surgical fixation was 15.85 minutes. A cumulative radiation dose of 0.4 mrem for the dominant arm of the assistant and 0 mrem for the primary surgeon was recorded. The mean DVA and CCA screw angles were 0.68° and 1.9°. 16/17 dogs had 100% sacral screw purchase with the remaining case achieving 93.4%.

Discussion/Conclusion: Accuracy of screw placement was not significantly different (p > 0.05) from the previously published MIO values of 1.2° (DVA) and 1.6° (CCA). Use of needles instead of a hand-held drill guide for aiming resulted in accurate screw placement and minimal radiation exposure to personnel in adherence with ALARA guidelines.

Acknowledgment: No proprietary interest. Funded by faculty startup funds