Lateral spinal profile in school-screening referrals with and without late onset idiopathic scoliosis 10 degrees-20 degrees.

INTRODUCTION: The aim of this report is a) to study the lateral spinal profile, (LSP), in school-screening referrals with and without late onset idiopathic scoliosis of small curves 10 degrees - 20 degrees Cobb angle and b) to validate LSP's aetiological importance in idiopathic scoliosis pathobiomechanics. METHODS AND MATERIAL: The spinal radiographs of 133 children, 47 boys and 86 girls with a mean age of 13.28 and 13.39 years respectively and Axial Trunk Inclination (ATI) > or = 7 degrees, were examined. The Cobb angle was appraised from the anteroposterior standing radiographs and the segmental spinal profile was assessed. A line was drawn down the posterior surface of each vertebral body from T1 to L5 on lateral standing radiographs, and the angle of this line from the vertical was recorded. Intervertebral values for LSP, (ILSP), that is the result of the subtraction of two consecutive spinal levels LSP, were also calculated. The data were then statistically analyzed.
RESULTS: The statistical descriptives of LSP and intervertebral LSP are presented for several groups of children, namely in those: 1) with straight spines, 2) with spinal curvature having a Cobb angle less than 10 degrees, and 3) in scoliotic children with a) thoracic, b) thoracolumbar and c) lumbar curves of 10 degrees-20 degrees. A correlation of the LSP with Cobb angle for the various types of curves for boys and girls is also presented. It is shown that the kyphotic segmental angulation is slightly less and the lordotic one almost normal in scoliotics, compared with the values of normal children. It is interesting to note that the LSP correlated with Cobb angle shows: a) a positive correlation pattern at T6, T7, T8 and T9 for thoracic curves of scoliotic boys and b) a negative correlation pattern at T3, T4 and T5 spinal levels of lumbar curves for scoliotic girls. DISCUSSION: The observed differences of the LSP are mainly located at the lumbar spine, suggesting that factors acting on the lumbar spine in sagittal plane contribute to the development of AIS. The minor hypokyphosis of the thoracic spine and its minimal differences observed in the studied small curves with nonscoliotics in this report add to the view that the reduced kyphosis, by facilitating axial rotation, could be viewed as being permissive, rather than as aetiological, in the pathogenesis of idiopathic scoliosis.