Special Poster Session 50th International Society for the Study of the Lumbar Spine Annual Meeting 2024

INTRODUCTION

The relationship between PI and lumbar lordosis in adults is well described and used to guide surgical planning. In children, the relationship is less clearly defined and the evolution of PI and segmental lordosis through growth reported in a limited fashion. Use of a radiographic measure of skeletal maturity offers an opportunity to further define the development of spinopelvic anatomy.

Using the modified Oxford Hip Score (mOHS) – described initially to predict the risk of contralateral slip in slipped capital femoral epiphysis - as a measure of skeletal maturity, the aim of this study was to report on the change in PI and segmental bony lumbar lordosis through childhood, using a CT dataset obtained from children with healthy spines.

METHODS 

CT performed for the assessment of major trauma or abdominal pathology in children aged 48 – 192 months was assessed. The PI and segmental vertebral body angles, L1-L5 inclusive, were obtained using the midsagittal CT image. Proximal lordosis (L1-3; PL), distal lordosis (L4-5; DL) and global lordosis (GL) were also noted. The mOHS was used to assess skeletal maturity comprising assessment of the femoral head (FH), greater trochanter (GT), lesser trochanter (LT), triradiate cartilage (TC) and the iliac apophysis (IL) with total scores ranging from 16-25 (least-most mature).

Pearson correlation co-efficients, linear regression and ANOVA were used to analyse relationships between variables.

RESULTS

A total of 200 consecutive scans were analysed. The mean age was 116 months (range 49-188; s.d. 41) including 66 female (33%).

There were significant positive correlations between age and all components of the mOHS: FH (r=0.783; p<0.001), GT (r=0.759; p<0.001), LT (r=0.706; p<0.001), TC (r=0.782; p<0.001), IL (r=0.628; p<0.001) and mOHS (r=0.833; p<0.001).

Significant correlation between PI and segmental lordosis values were evident at L1 (r=-0.146; p=0.039), L3 (r=0.302; p<0.001) and L4 (r=0.357; p<0.001). PI correlated significantly with PL (r=0.272; p<0.001) and GL (r=0.198; r=0.005).

 Mean PI for the entire cohort was 40.7 (s.d. 8.9; range 19.3 – 69.4). There were significant albeit weak correlations with FH (r=0.258; p<0.001), GT (r=0.225; p=0.001), LT (r=0.281; p<0.001), TC (r=0.298; p=<0.001), IL (r=0.228; p=0.001) and total mOHS (r=0.253; p<0.001). Multivariable linear regression indicated the TC the best predictor of PI.

Significant correlations were seen between L1 segmental lordosis and all components of the mOHS, the strongest with triradiate ((r=-0.406; p<0.001). L3 segmental lordosis correlated significantly with the total mOHS (r=0.145; p=0.041). L5 segmental lordosis corelated significantly with the IL (r=-0.179; p=0.011). Proximal lordosis correlated significantly with all components of the mOHS, most strongly with TC (r=-0.228; p=0.001). Global lordosis correlated significantly with LT, TC and IL, most strongly with the latter (r=-0.202; p=0.004).

DISCUSSION

In this CT-based study, the mOHS correlated weakly, albeit more so than age, with PI and proximal segmental lordosis. Of the mOHS components, triradiate cartilage status appeared to be best correlated with PI and vertebral body lordosis and should be considered in future analyses.