Sagittal Imbalance In Degenerative Scoliosis.Can C7 Pelvic Angle Replace SVA?

Objective: To explore whether C7 pelvic angle can evaluate the sagittal balance,and to investigate the relationship between CPA and health related quality of life of patients with adult degenerative scoliosis(ADS).Methods: The data of ADS patients who received surgical treatment in Shandong provincial hospital from February 2010 to January 2017 were retrospectively analyzed.67 ADS patients were included.The sagittal alignment parameters were measured on both preoperative and last follow-up radiographs,including pelvic incidence(PI),sacral slope(SS),pelvic tilt(PT),thoracic kyphosis(TK),lumbar lordosis(LL),sagittal vertical axis(SVA),C7/SFD,CPA.ODI scores,VAS and SRS-22 total scores were also analyzed by using SPSS version 21.0.Results: There was no significant correlation between SVA and PI,TK,SS,but negative correlation with LL,and positive correlation with PT and CPA,the same as C7/SFD.CPA has no significant correlation with PI and TK,but negatively correlate with LL and SS,and is positively correlated with PT and SVA.Sagittal plane evaluation at last follow-up: SVA had no significant correlation with PI,PT,SS,TK,C7/SFD,negative correlation with LL,and positive correlation with CPA.CPA has no significant correlation with PI,PT,SS,TK,C7/SFD and is negatively correlated with LL.Preoperative quality of life evaluation: SVA was positively correlated with preoperative VAS score and ODI score,and negatively correlated with SRS-22 total score.Preoperative C7/SFD was positively correlated with preoperative VAS score and ODI score,and negatively correlated with SRS-22 total score.CPA was positively correlated with VAS and ODI,and negatively correlated with SRS-22.The overall correlation between CPA and quality of life is stronger than that between SVA and C7/SFD.Evaluation of changes before the final follow-up: CPA was positively correlated with changes in VAS and ODI,and negatively correlated with changes in SRS-22.The change value of SVA was positively correlated with the change value of VAS and ODI,and negatively correlated with the change value of SRS-22 total score.Conclusion: CPA could better reflect spinal-pelvic sagittal balance and health related quality of life,and the guiding significance of ADS reconstructive surgery is more important.