Lumbar Sagittal Shape Variation vis-à-vis Gender During Growth: A Three-Year Follow-Up Mri Study in Children from the General Population

ABSTRACT: Study Design. A longitudinal descriptive MRI study on the changes of the supine lumbar lordosis (SLL), supine sacral slope (SSS), and sagittal wedging of the vertebral body (VB) and intervertebral discs (IVD) in children from the general population.Objective. To compare the shape variation during growth of the SLL, SSS and sagittal wedging of the VB and IVD in boys and girls.Summary of Background Data. The normal shape variation of the VB, IVD, SLL and SSS during growth vis-à-vis gender in children from the general population is poorly clarified in the literature as it is usually reported in relation to pathological conditions.Methods. The SLL, SSS and sagittal wedging of all lumbar (L1-S1) VB's and IVD's, were measured twice from T2-weighted MRIs of 100 healthy children (51 boys and 49 girls), mean age 12-13 years (t0) and following almost three years later (t1) using the iQ-VIEW system. Data for Body compositions and pubertal status was collected and their correlations were analyzed.Results. At baseline (t0), most lumbar VB's were significantly more lordotic in boys (17.1º) than in girls (22.2º); however, girls manifested greater SLL and SSS (45.2º and 33.6º, respectively) than boys (40.7º and 31.4º, respectively), and all IVD's were lordotic with only the L5-S1 IVD differing between genders, being more lordotic in girls than in boys (mean difference = 2.8º). At follow up (t1), SSS became greater in boys (35.7º) than in girls (32.5º) yet all other parameters became independent of gender including all IVD's (except L5-S1) becoming significantly more lordotic, and more so in boys than in girls (total lumbar means differences being 9.0º and 3.8º, respectively). Increase in boys' heights was correlated with the increase in the L2-L4 lordotic IVD wedging (r = 0.45). Positive correlations were indicated between puberty Tanner stage and individual's height and weight (0.41