Morphometric analysis of vertebral deformities in a porcine scoliosis model

Abstract

Idiopathic scoliosis is a three dimensional deformity of the spine associated to local vertebral deformities such as: vertebral wedging, vertebral torsion and pedicular and neural arch asymmetry. No spontaneous animal model of scoliosis is known. Indeed, development of model are needed to better understand, the pathogenesis, the biomechanics of the disease. A scoliosis model was developed by asymmetric tethering of the thoracolumbar spine in a growing pig. This model created a reproducible structural scoliosis like deformity The purpose of this study is to describe the vertebral deformities in a porcine scoliosis model. Vertebral deformities were assessed in 5 porcine scoliosis model. The mean Cobb's angle was 39.4° +/- 6° in frontal plane and 43° +/- 8° in sagittal plane. Mean thoracic rotation was 38.4°+/-9.8°. Wedging of the vertebral body in frontal and sagital plan, pedicular and neural arch asymmetry was assessed for each vertebra. Thrirty-two vertebrae were included in this study. Mean vertebral wedging was 9,2° (+/- 3°) in frontal plan and 3,4° (+/- 1,1°) in sagittal plan. Wedging is more important for the summit vertebra and increase with Cobb's angle. Length and inclinaison of left and right pedicule was not statistically different. Nevertheless, at the summit vertebra, a trend for a smaller pedicule on the concave side of the deformity was observed. Length of the dorsal arch was similar on each side, but the dorsal arch on the concave side of the deformity tend to be more flattened. Vertebral deformities were observed in this porcine scoliosis model. The principal deformity is a wedging of the vertebral body mainly in the frontal plan. This wedging is more pronounced when the Cobb's angle increase and at the summit vertebra. Those deformities are similar to vertebral deformities observed in human idiopathic scoliosis. © 2010 International Federation for Medical and Biological Engineering.