Biomechanical modelling of impact-related fracture characteristics and injury patterns of the cervical spine associated with riding accidents

- A simulator test was established to mimic an impact-related accident.
- Human cervical spines were mechanically tested and their injury patterns assessed.
- Superior specimens demonstrated higher stress-to-failure than inferior ones.
- Spines in extension showed severe fractures mostly with narrowing of the spinal cord.
- A neutral spine position during an accident may reduce the severity of the injury.

BackgroundHorse-related injuries are manifold and can involve the upper and lower limbs, the trunk, spine or head. Cervical spine injuries are not among the most common injuries. However, they can be fatal and often result in neurological symptoms. This study investigated the influence of the posture of the cervical spine on the ultimate strength and the pattern of vertebrae failure with the aim to provide some guidance for protective clothing design.MethodsEighteen human cervical spines, each divided into two specimens (three vertebrae each), were subjected to a simulator test designed to mimic a spinal trauma in different postures of the specimen (neutral, flexion, extension). The stress-to-failure, the deformation at the time of fracture and the fracture patterns assessed based on CT scans were analysed.FindingsStress-to-failure of the superior specimens was lower for the flexion group compared to the others (P = 0.027). The superior specimens demonstrated higher stress-to-failure in comparison to the inferior specimens (P < 0.001). Compression in a neutral or flexed position generated mild or moderate fracture patterns. On the contrary, the placement of the spine in extension resulted in severe fractures mostly associated with narrowing of the spinal canal.InterpretationThe results imply that a neutral cervical spine position during an impaction can be beneficial. In this position, the failure loads are high, and even if a vertebral fracture occurs, the generated injury patterns are expected to be mild or moderate.