Analysis of Posterior Trunk Symmetry Index (POTSI) in scoliosis. Part 2

Moire pictures of fifty-five normal children and 195 cases of scoliosis pat ients were analyzed. Among them 40 cases were treated surgically by 3-D Har rington instrumentation. Cobb angle, and the coronal plane asymmetry indice s (FAI, HDI:), POTSI and Hump Sum were analyzed. A slight trunk asymmetry w ere detected in the normal children. The mean values of all the parameters in the scoliosis group were significantly larger than those in the normal c ases (p<0.01). A weak correlation was found between POTSI and Cobb angle (r =0.435, p<0.0001). The preoperative POTSI of 46.9 decreased to 24.3 postope ratively. Lateral curvature: and trunk deformity including hump and trunk a symmetry should be evaluated separately because these are three different m ajor factors of scoliois. Therefore, Cobb angle, Hump Sum and POTSI must be measured in the evaluation of scoliosis treatment. The new parameter intro duced here as POTSI is clinically useful to assess the trunk deformity quan titatively.