The positive correlation between upper adjacent vertebral fracture and the kyphosis angle of injured vertebral body after percutaneous kyphoplasty: An in vitro study.

OBJECTIVE

To investigate the correlation between the kyphosis angle of injured vertebral body and the risk of upper adjacent vertebral fracture after percutaneous kyphoplasty (PKP) using an osteoporotic vertebral compressed fracture model.

MATERIALS AND

METHODS

24 functional spinal units (FSUs, T9 to L4) were selected from 6 elderly formalin preserved vertebral specimens to build the vertebral compressed fracture model. According to the kyphosis angle between the upper plate of upper vertebral body and the horizontal plane, group A (0°) and group B (20°) were defined, with each group comprised with 12 FSUs. The stiffness and fracture load were measured in both groups.

RESULTS

After PKP, the stiffness was (571.513 ± 83.373)N/mm and the fracture load was (1751.659 ± 112.291)N in group A, with both significantly higher than those of group B (stiffness, (307.706 ± 46.723)N/mm; fracture load, (1128.011 ± 125.417)N).

CONCLUSIONS

To reduce the risk of upper adjacent vertebral fracture, it is better to restore the height of injured vertebral body and decrease the angle of kyphosis to increase the capability of upper adjacent vertebral body against fracture.