Influence of upper fused vertebra on postoperative shoulder balance for Lenke type 1 adolescent idiopathic scoliosis

English Keywords:Adolescent idiopathic scoliosis  Lenke type 1  Shoulder balance  Upper fused vertebra

English Abstract:

  【Abstract】 Objectives: To analyze the influence of upper fused vertebra on postoperative shoulder balance in Lenke type 1 adolescent idiopathic scoliosis(AIS) patients with preoperative leveled shoulders. Methods: A total of 32 Lenke type 1 AIS patients with preoperative leveled shoulders was included in the study. There were 6 boys and 26 girls with an average age of 14.9 years old(range, 13-19 years). The average preoperative proximal thoracic curve was 23.7°±8.0°(range 10°-36°), and the average preoperative main thoracic curve was 47.5°±6.9°(range 40°-62°). Thirty-two patients undergoing posterior thoracic fusion were divided into two groups: group A(n=19) included those who had a proximal fusion to T3; group 2(n=13) included those who had a proximal fusion to T4. There was no significant difference in demographics or baseline characteristics between group A and B including age at operation, Risser stage, flexibility of proximal and main thoracic (PT and MT) curves(P>0.05). Based on analysis of variance, radiographic parameters were compared among preoperation, 1 year follow-up and the final follow-up including PT and MT curve Cobb angle, apical vertebral translation(AVT), trunk shift, radiographic shoulder height(RSH), coracoids process height(CPH) and clavicle angle(CA). Results: In group A, the follow-up time ranged from 2 to 4.5 years with an average time of 3.6±1.3 years; while in group B, the follow-up time ranged from 2 to 4.8 years with a mean time of 3.1±2.1 years, which showed no difference between two groups(P>0.05). At preoperation, 1 year follow-up and the final follow-up, there were no significant differences in radiographic outcomes between group A and B including PT and MT curve Cobb angle, AVT, trunk shift, RSH, CPH and CA(P>0.05). For all patients, PT and MT curve Cobb angle, AVT, trunk shift, RSH, CPH and CA at 1 year follow-up and the final follow-up were both better than those before surgery(all P<0.05); while the values of RSH, CPH and CA at final follow-up were lower than those at 1 year follow-up(P<0.05). All patients obtained the balanced shoulders after surgery. Conclusion: For the Lenke type 1 AIS patient with leveled shoulder, proximal fusion to T4 can produce equivalent correction of scoliosis and shoulder balance.