Analyze The Influence Of Shoulder Balance With Right Shoulder Height Lenke 1 Adolescent Idiopathic Scoliosis Following Orthomorphia

Objective: To investigate the changes of radiographic shoulder height in patients with Lenke type 1 adolescent idiopathic scoliosis(AIS)with preoperative right higher shoulder after selective thoracic fusion,and analyse the factors associated with postoperative shoulder imbalance.Methods: A retrospective review of 41 Lenke type 1 AIS patients with preoperative right higher shoulder were treated with posterior correction from January 2012 to December 2017.According to postoperative radiographic shoulder height,the cases were divided into two groups:Group A,which has the postoperative shoulder balance and the Number is 31;Group B,which has the postoperative shoulder imbalance and the Number is 9.In preoperative,three months follow-up and the last follow-up(at least 2 years),X-rays were taken to measure imaging indices,including radiographic shoulder height(RSH),the proximal thoracic curve Cobb angle,the main thoracic curve Cobb angle,clavicle angle(CA),clavicle chest cage angle difference(CCAD)and T1 tilt angle.The correlation between the last follow-up RSH and preoperative imaging indices were analyzed,and the correlation between the last follow-up RSH and correction rate of the proximal,main thoracic curve and CA change also been analyzed.Results:Comparison between two groups in 41 patients with preoperative right higher shoulder,there are no significant difference including sex,age,Risser stage,preoperative RSH,preoperative thoracic kyphosis and preoperative lumbar lordosis(p>0.05).After operation,the patients in two groups both got satisfactory correction of RSH,PT curves and MT curves(p<0.05).There are significant difference between two groups including preoperative CA,CCAD and proximal thoracic curve flexibility(p<0.05),but there are no significant difference including main thoracic curve flexibility,PT curves and MT curves(p>0.05).In each group,there are significant difference of CA and CCAD in the follow-ups(p<0.05),but no significant difference of T1 tilt(p>0.05).Correlation analysis showed that preoperative CA and CCAD are positively correlated with the last follow-up RSH(p<0.05,r>0)and the proximal thoracic curve flexibility is negatively corrected with the last follow-up RSH(p<0.05,r<0),and there is a positive correlation among CA change,the proximal thoracic curve correction rate,the main thoracic curve correction rate,the main thoracic curve angle change with the RSH change(p<0.05,r>0).Meanwhile,the CA change is significantly collected with the main thoracic curve correction rate as well as the main thoracic curve angle change(p<0.05,r>0),while other preoperative imaging indices are no significantly correlated with the postoperative RSH(p>0.05).Conclusion: Preoperative CA,CCAD and flexibility of the proximal thoracic curve may be predictors of postoperative shoulder balance,while overcorrection of the proximal thoracic curve and main thoracic curve may cause a postoperative shoulder imbalance.