Comparison of morphometric measurements of lumbar muscles on the convex and concave sides of curvature in idiopathic scoliosis.

It has always been wondered how the muscle volumes of the lumbar region are affected on the convex and concave sides of the curvature in idiopathic scoliosis (IS) and their possible differences compared to healthy individuals. Muscular changes in individuals with IS have generally been tried to be determined by measurements such as muscle cross-sectional area. However, since the changes in the locomotor system in scoliosis affect the anatomical structures of the muscles such as origin and insertion, the reliability of muscle cross-sectional area measurement decreases. Our aim in this study was to compare the psoas major (PM) and quadratus lumborum (QL) muscle volumes, which undergo the most changes on the concave and convex side of the curvature in scoliosis, within themselves and with healthy individuals. 34 women with scoliosis and 29 healthy women were included in this descriptive retrospective study. PM and QL muscle volumes were measured bilaterally on computed tomography (CT) images of individuals in both groups and recorded as mm3. Statistical analysis was performed with IBM SPSS 23.0, P < .05 was considered significant. In the IS group, both PM and QL muscle volumes were greater on the convex side of the curve (P < .001). When the IS group was compared with the control group, both muscle volumes were significantly lower in the IS group bilaterally than in the control group (P < .001). It was observed that individuals with IS developed atrophy in the lumbar muscles of both sides of the curve, mostly on the concave side of the curve, compared to healthy individuals. We think that these results will be important in planning appropriate physical therapy for individuals with IS.