Segmental Rib Index and Spinal Deformity: Scoliogenic Implications.

The aim of this report is to evaluate the segmental rib index (RI) from the T1 to T12 spinal levels in mild and moderate idiopathic scoliosis (IS) curves of thoracic, thoracolumbar and lumbar type by gender. The relationship of segmental RI to the frontal plane radiological deformity presented as the Cobb angle and to the posterior truncal surface deformity presented as the scoliometric readings of Angle of Trunk Rotation (ATR) in these patients is also assessed. Any statistically significant relationship between these parameters would be very important for biomechanical relations in rib cage (RC) deformity presented as rib hump deformity (RHD) and deformity in the spine, and would thus provide valuable information about scoliogeny. The segmental rib index (RI) is presented in 83 boys and girls with mild and moderate IS. The measurements include the scoliometric readings for truncal asymmetry (TA), the Cobb angle assessment and the segmental RI from T1-T12. The statistical package SPSS 23 was used for statistical analysis. The TA was documented and the Cobb angle is presented by gender and curve type. The segmental RI of thoracic, thoracolumbar and lumbar curves are presented for the first time. The correlations of the segmental RI to surface deformity presented as rib hump deformity (RHD) in all IS patients, and particularly in thoracic curves, to Cobb angle by gender and age and the comparison of the segmental RI index of asymmetric but not scoliotic children to the scoliotic peers by curve (in thoracic, thoracolumbar, lumbar curves) in boys and girls are presented. The findings emphasize the significant protagonistic role of thoracic asymmetry in relation to the spinal deformity, mainly in girls for the thoracic and in boys for the thoracolumbar curves. The cut-off point of age of the examined scoliotics was 14 years, which is when the RI shows a stronger correlation with spinal deformity, namely when thoracic deformity is decisively effective in the development of thoracic spinal deformity, in terms of Cobb angle. In summary, the results of this study may provide scoliogenic implications for IS, as far as the role of the thorax is concerned.