How well do radiological measurements correlate with cosmetic indices in adolescent idiopathic scoliosis with Lenke 5, 6 curve types?

STUDY DESIGN

An association study between radiologic measurements and cosmetic appearance in adolescent idiopathic scoliosis (AIS) patients with Lenke 5 and 6 curve types.

OBJECTIVE

The present study aimed at investigating the correlation between radiologic measurements and clinical cosmetic assessment indices in AIS with Lenke 5 and 6 curve types.

SUMMARY OF BACKGROUND DATA

Cosmetic truncal and pelvic distortions are of important concern to patients with AIS. In the clinical assessment of AIS, over reliance on radiologic evaluations without corresponding objective assessment of the external physical appearance is commonly practiced. Patients having the same radiologic findings could be quite different in their physical appearance and the reverse could also happen. These observations imply that discrepancies could well exist in the cosmetic versus radiologic evaluation in AIS.

METHODS

A total of 52 AIS patients with dominant lumbar/thoracolumbar curve including 36 Lenke type 5 and 16 Lenke type 6 were recruited. Cobb angles, coronal balance, thoracic containment, apical vertebral translation (AVT), pelvic oblique, apical vertebral rotation were measured in the standard long-standing posteroanterior radiographs. Waistline Height Index, Waistline Depth Index, Waistline Area Index, Waist Area Index, and hump index (α) were measured clinically and the 5 parameters combined into a composite cosmetic Index (CCI). Pearson rank correlation coefficient was used to assess measurement reliability for the cosmetic indices; correlation analysis and multiple linear regression analysis were made between the radiologic measurements and CCI.

RESULTS

The correlation coefficients between radiologic measurements and CCI ranged from -0.29 to 0.57, among which AVT was found to have the highest correlation coefficient, but not the Cobb angle. AVT, Cobb angle, coronal balance, thoracic containment were found to be significantly correlated with CCI (P < 0.05) with all correlation coefficients below 0.6. From linear regression analysis, CCI could be predicted by the equation (CCI = 98.0-1.18 x AVT-0.29 x Cobb angle) with adjusted R2 of 0.33 (implying that 33% of CCI variation could be accounted for by Cobb angle and AVT).

CONCLUSION

The present study showed that a number of radiologic indices could only partially reflect the objective cosmetic appearances in Lenke type 5 and 6 curves in AIS. Spine surgeons should put more emphasis in the clinical cosmetic evaluations and not relying solely on the radiologic assessment in AIS.