Discrepancy in clinical versus radiological parameters describing deformity due to brace treatment for moderate idiopathic scoliosis

BACKGROUND The shape of the torso in patients with idiopathic scoliosis is considered to reflect the shape of the vertebral column, however the direct correlation between parameters describing clinical deformity and those characterizing radiological curvature was reported to be weak. It is not clear if the management proposed for scoliosis (physiotherapy, brace, surgery) affects equally the shape of the axial skeleton and the surface of the body. The aim of the study was to compare clinical deformity of (1) idiopathic scoliosis girls being under brace treatment for radiological curves of 25 to 40 degrees and (2) non treated scoliotic girls matched for age and Cobb angle. METHODS Cross-sectional study of 24 girls wearing the brace versus 26 girls without brace treatment, matched for age and Cobb angle. HYPOTHESIS Patients wearing the brace for more than 6 months, when comparing to patients without brace, may present different external morphology of the trunk, in spite of having similar Cobb angle. Material. INCLUSION CRITERIA girls, idiopathic scoliosis, growing age (10-16 years), Cobb angle minimum 25 degrees , maximum 40 degrees . The braced group consisted of girls wearing a TLSO brace (Cheneau) for more than 6 months with minimum of 16 hours per day. The non-braced group consisted of girls first seen for their spinal deformity, previously not treated. The groups presented similar curve pattern. Methods. Scoliometer exam: angle of trunk rotation at three levels of the spine: upper thoracic, main thoracic, lumbar or thoracolumbar. The maximal angle was noted at each level and the sum of three levels was calculated. Posterior trunk symmetry index (POTSI) and Hump Sum were measured using surface topography. RESULTS Cobb angle was 34.9 degrees +/- 4.8 degrees in braced and 32.7 degrees +/- 4.9 degrees in un-braced patients (difference not significant). The age was 14.1 +/- 1.6 years in braced patients and 13.1 +/- 1.9 years in un-braced group (p = 0.046). The value of angle of trunk rotation in the main curvature was 8.4 degrees +/- 2.7 degrees in braced and 11.4 degrees +/- 2.7 degrees in un-braced patients (difference extremely significant, p = 0.0003). The value of the sum of angles of trunk rotation at three levels of the trunk was 12.8 degrees +/- 4.6 degrees in braced and 16.5 degrees +/- 3.8 degrees in un-braced patients (difference very significant, p = 0.0038). The POTSI did not differ significantly between the groups (p = 0.78), the Hump Sum values were not quite different (p = 0.07). CONCLUSION (1) Adolescent girls wearing the brace for idiopathic scoliosis of 25 to 40 degrees of Cobb angle, reveal smaller clinical rotational deformity of their back than non-treated girls having similar radiological deformity. (2) Evaluation of the results of treatment for idiopathic scoliosis should consider parameters describing both clinical and radiological deformity.