Resident, Equine Surgery Colorado State University Fort Collins, Colorado
Computed Tomography Versus Radiographic Guidance for Internal Fixation of Central Tarsal Bone Fractures in Non-Racing Horses. Smanik L, Selberg K, Kawcak C, Stewart H, Goodrich L. Colorado State University, Fort Collins, CO.
Internal fixation of central tarsal bone (CTB) fractures in horses can be improved by an accurate understanding of fracture configuration prior to surgery. In clinical cases, CT has provided additional information not detected on preoperative radiographs that altered the surgical plan. The purpose of this equine cadaveric study was to compare the accuracy of screw placement in simulated dorsomedial-plantarolateral CTB fractures using CT and fluoroscopy compared to radiographic guidance in 10 pairs of cadaver tarsi. The techniques used for marker placement with each guidance method will also be described. For this study, one tarsus of each pair had a screw placed using CT and fluoroscopy, and the other with radiographic guidance. Postoperative CT was performed on all limbs. Preliminary analysis suggested that the average deviation of screws from perpendicular to the fracture plane was lower using radiographic guidance (3.38°) compared to CT/fluoroscopy (6.15°). There appeared to be no difference in the tendency to involve adjacent articular surfaces between groups. Subjectively, screws placed under radiographic guidance deviated more from the center of the CTB with greater variability in screw trajectory. Mild adjustments to the fluoroscopic or radiographic angle can dramatically alter the perception of screw placement within the bone. As CT imaging may not be available to every surgeon, the establishment of techniques for both CT/fluoroscopic and radiographic guidance may improve accuracy and simplify repair of these fractures using either imaging modality. Study limitations included small sample size and use of normal equine cadaver limbs.