Rib index is a strong surrogate of scoliometric reading in idiopathic scoliosis.

Abstract

Scoliometry is not always included in the examination protocol of IS patients. The aim of this report is to examine the degree of correlation of Segmental Rib Index (SRI) to scoliometry, in order for SRI to be used as a surrogate of scoliometric angle of trunk rotation (ATR). 66 Idiopathic Scoliosis (IS) subjects were studied, with a mean age 12.2 ± 2.9years, 18 boys and 48 girls: 20 thoracic, 22 thoracolumbar and 24 lumbar curves. The standing lateral spine radiographs (LSR) were obtained and the Segmental Rib Index (SRI) from T1 to T12 were assessed. The ATR was documented. In all 66 cases with IS the scoliometer readings (ATR) were significantly correlated to the SRI at the T6, T7 and T8 levels. In the thoracic curves SRI and ATR correlations were significant for the levels T6-T12. It was suggested that as long as the patients doesn't have scoliometer measurements, the SRI, could be used as a surrogate for scoliometry. It was also found that in thoracic, thoracolumbar and lumbar level, in both genders, changing from the flexed position to the standing position, the mean trunk asymmetry (TA) decreases. Therefore, if these patients had their TA measured using a scoliometer during the Adams test, their body asymmetry would have been greater than that measured using the SRI method on standing LSR. Consequently, it is evident that the significantly correlated SRI used as a surrogate for the scoliometric assessment of TA is reasonably a strong surrogate.