Ex vivo evaluation of the cranial tibial artery and its compression through fragment rotation during tibia plateau levelling osteotomy : an angiographic three-dimensional reconstruction

Objective

 To illustrate the arterial vascularity of the proximal tibia three-dimensionally and to evaluate the impact of fragment rotation on the cranial tibial artery by tibia plateau levelling osteotomy (TPLO).

Methods

 Radiographic angiography and computed tomography (CT) were performed on 12 pelvic limbs from six large-breed canine cadavers before and after TPLO. Three-dimensional (3D) models of the stifle, including osseous and vascular structures, were obtained, and the integrity of the cranial tibial artery was assessed. Post-TPLO CT images were used to analyze compression of the cranial tibial artery by the rotated fragment.

Results

 The uncompressed cranial tibial artery caliber, measured proximally and distally to the osteotomy, was 9.52 mm² (6.07-18.90 mm²). In all adequately rotated fragments, the mean caliber of the artery on the level of the osteotomy was 1.57 mm² (0.89-2.93 mm²) after TPLO. This represented a significant decrease of approximately 81%. Only slight cross-sectional area decrease (8.8%) was seen in one limb, which was revealed to have insufficient fragment rotation (2.83 mm). Another limb only showed signs of stretching of the artery (31.51%), which was under-rotated and medially displaced. Pre-TPLO 3D reconstructions were mainly consistent with previous anatomic studies except for the distance between tibial cortex and cranial tibial artery, which appeared closer.

Conclusion

 Sufficient fragment rotation leads to compression of the cranial tibial artery. Intraoperative hemorrhage can be caused by laceration of the main cranial tibial artery or by multiple small branches reaching craniolaterally.