The influence of coronal deformity on sagittal parameters of adolescent idiopathic scoliosis

English Keywords:Adolescent idiopathic scoliosis  Coronal deformity  Sagittal alignments  Radiographic study

English Abstract:

  【Abstract】 Objectives: To investigate the relationship between coronal deformity and sagittal alignments of patients with adolescent idiopathic scoliosis(AIS). Methods: The X-rays of AIS patients were retrospectively reviewed from June 2006 to October 2012. The parameters were measured included: Cobb angles of structural curves, thoracic kyphosis(TK), lumbar lordosis(LL), sacral slope(SS), pelvic incidence(PI), pelvic tilt(PT), spino-sacral angle(SSA) and C7 translation ratio(C7TR). Lenke and Roussouly classifications of all patients were recorded to compare the sagittal parameters of the subjects with different Lenke curve types(CT), Lenke lumbar modifiers(LM) and curve amounts(CA). Correlation analysis was performed between coronal and sagittal parameters. Results: A total of 165 AIS patients with 45 males and 120 females was recruited. The mean age was 14.8±2.0 years old. The amount of subjects from Lenke 1 to Lenke 6 was 70, 33, 15, 21, 17 and 9 respectively. The mean PI was 43.0°±9.3°. No significant differences of parameters in each group were found except for TK and PT among different CT groups. TK, LL and PT among different CA groups was significantly different(P<0.05), while only TK showed such difference in each LM group. The subjects with different Lenke types had similar distribution of Roussouly classification(P=0.753). Besides, the Cobb angle of main thoracic curve was negatively correlated with LL, SS and SSA(P<0.05). No significant correlation was found between Cobb angle of lumbar curves and sagittal parameters. Conclusions: Coronal deformities in AIS patients can affect the values of some sagittal spinopelvic parameters, but don′t not change the distribution of sagittal postural patterns. AIS patients in different types have different TK, LL and PT values while a similar PI value. And the above relationships between coronal and sagittal parameters should be considered in the correction surgery of AIS patients.