Spino-pelvic sagittal alignment analysis in severe adult idiopathic scoliosis

English Keywords:Idiopathic scoliosis  Severe scoliosis  Sagittal balance  Coronal plane  Pelvic alignment

English Abstract:

  【Abstract】 Objectives: To investigate the spino-pelvic sagittal alignement characters of severe scoliosis. Methods: A total of 79 asymptomatic volunteers(normal group), 83 mild scoliosis and 69 severe scoliosis patients were recruited in this series. The following coronal and sagittal parameters were measured: (1)Coronal alignments: coronal Cobb angle of the main curve, coronal balance(CB) and apical vertebral translation(AVT); (2)Sagittal alignments: thoracic kyphosis(TK), thoracolumbar kyphosis(TLK), lumbar lordosis(LL), pelvic incidence(PI), pelvic tilt(PT), sacral slope(SS), sagittal vertical axis(SVA), pelvic thickness(PTH), sacral femoral distance(SFD), sacral pelvic angle(PRS1), PI minus LL(PI-LL), ratio of PT and PI(PT/PI) and the distance between hip axis and C7PL(HA-C7PL). Correlations of the parameters between two groups were determined by using the Pearson correlation coefficient. Comparison of the values for the same parameters in different groups was done with a one-way ANOVA and rank-sum test. Results: Compared to normal group, in severe scoliosis, LL, TLK, TK and PRS1 increased significantly, PI, PT, PTH, SFD and PI-LL decreased significantly;while SVA(within normal range) increased significantly and SS decreased significantly in thoraco-lumbar/lumbar curve scoliosis. Correlations were absent between coronal parameters and sagittal parameters in normal group and mild thoracic curve scoliosis, while correlation of Cobb angle with TK existed and TLK in the other three groups. Different correlations between CB and sagittal parameters were present in mild thoraco-lumbar/lumbar curve scoliosis and severe scoliosis curves. Correlations were present between LL and TK, LL and TLK, PI and PT, PI and SS. Correlation between TK and TLK was present in normal group and severe scoliosis patients. Correlation between TK and SVA was only present in severe scoliosis patients. Correlation between LL and SVA was only present in thoraco-lumbar/lumbar curve scoliosis. Conclusions: Increased TK, TLK, LL and decreased PI, PT are common in severe scoliosis, and severe scoliosis patients tend to have a narrow and horizontal shape pelvis.