Vertebral end‐plate failure in porcine‐and bovine models of spinal fracture instrumentation

Abstract

The use of mature porcine and immature bovine spines as models for the assessment of spinal fracture instrumentation is commonplace. By comparing the load-displacement characteristics of these spine segments and observing the fracture type, this study investigated the tendency of immature bovine spines to fail prematurely at the vertebral physis, disrupting biomechanical evaluation of spinal fracture fixation devices. Load to failure of the spines was determined using the Instron Universal Testing Machine and a specially designed endcap. In axial compression, the 10–16-week-old calf spines failed at 12,845 ± 1,466 N, compared with mature pig spines at 17,300 ± 5,170 N (p < 0.05). Axial compression with flexion caused consistent failure through an end-plate in both species: 995 ± 156 N for the calf spines and 2,025 ± 575 N for the porcine spines (p < 0.005). It was concluded that the tendency for immature bovine spines to fail more readily at the cartilaginous end-plate makes the calf spine a less desirable model.