Radiation exposure associated with percutaneous fluoroscopically guided lag screw fixation for sacroiliac luxation in dogs

Authors: 
Jaron H Naiman, Eric M Zellner, Brian L Petrovsky, Thomas O Riegel, Elizabeth M Schmitt, Lingnan Yuan, Jonathan P Mochel, Karl H Kraus
Vet Surg. 2021 May 6. doi: 10.1111/vsu.13613.

Objective: To determine radiation exposure to surgical personnel and to evaluate the accuracy of a modified percutaneous lag screw fixation technique for sacroiliac luxation (SIL) under fluoroscopic guidance in dogs.

Study design: Cadaveric experimental study.

Sample population: Seventeen beagle cadavers with iatrogenic SIL.

Methods: Seventeen beagles with iatrogenic SIL underwent reduction and stabilization with 3.5-mm screws. Hypodermic needles (14 gauge) and fluoroscopy were used to orient two Kirschner wires for temporary stabilization and to guide drilling of glide and pilot holes using cannulated drill bits. Duration of surgery and radiation exposure were recorded. Postoperative computed tomographic evaluation of screw position and angulation was performed.

Results: Average time for fixation was 15.85 minutes (range, 6.37-33.5). Cumulative radiation doses of 0.4 mrem for the dominant arm of the assistant and 0 mrem for the primary surgeon were recorded. The mean dorsoventral and craniocaudal screw angles were 0.68° ± 3.4° (range - 5.4° to 9.5°) and 1.9° ± 3.2° (range - 4.3° to 9.1°), respectively. Sixteen of the 17 dogs had 100% sacral screw purchase, with the remaining case achieving 93.4% purchase.

Conclusion: Fluoroscopy-assisted percutaneous placement of 3.5-mm cortical screws in lag fashion performed with 14-gauge needles in conjunction with Kirschner wires and cannulated drill bits yielded repeatable accurate screw placement with low levels of ionizing radiation exposure to the surgical team.

Clinical significance: The described technique may be a viable method for minimally invasive osteosynthesis fixation of SIL with low levels of radiation exposure to the surgical team. These results provide evidence to support further evaluation of radiation exposure in clinical cases and can aid in study design and sample size determination.