195 – 3D SPINE MORPHOLOGIC DIFFERENCES AT FIRST VISIT BETWEEN NON-EVOLUTIVE AND AN EVOLUTIVE ADOLESCENT IDIOPATHIC SCOLIOSIS

Abstract

Purpose: Prediction of progression is actually impossible in adolescent idiopathic scoliosis (AIS). Potential risk factor to consider at first visit might be morphologic parameters of the spine. The objective of this study was to compare 3D morphologic parameters of the spine in a non evolutive an in an evolutive group of AIS.

Method: A retrospective cohort study was done. Two groups were recruited with sample size based on a difference of 5 degrees for rotation parameters. First group were all surgical patients (n=19) and second group non evolutive patient (n=18). Inclusion criteria were

1. Risser sign of 0 or 1

2. Cobb angle between 11 and 40 degrees

3. AP and lateral radiograph available.

Exclusion criteria were

1. limb length discrepancy

2. syndromic or congenital scoliosis.

All spines were reconstructed in 3D with AP and lateral radiographs of the first visit and measurements were performed on the reconstruction. There were 4 categories of measurements done: Cobb angle, wedging, rotation, slenderness. Student t test were performed.

Results: There was no statistical difference between the two groups for Cobb angle in maximal plane, for lordosis and kyphosis. Differences were found for wedging of the apical disk in 3D plane (S=5,4° vs NE= 0,7° with p=0,04). For coronal orientation of the apex (S=7,8° vs NE=0,1° with p=0,01). For axial orientation of inferior junctional vertebrae (S=1,9° vs 0,1° with p=0,007). For torsion (S=−4,1° vs NE= – 1,2° with p=0,03). For ratio between height and width of T6 (S=51% vs NE=53,6% with p=0,04).

Conclusion: This study give for the first time some 3D morphologic parameters that could be use in the prediction of AIS. Some limitations exist such as the small sample size and the low level of significance. In the future those parameters will be used in the development of a prediction model base on those keys parameters that will confirm the actual findings.