Comparison of spontaneous correction in thoracic curves after selective anterior versus posterior fusion in Lenke5 adolescent idiopathic scoliosis

[Objective]To compare spontaneous correction of the unfused thoracic curves after selective anterior versus posterior fusion in Lenke5 adolescent idiopathic scoliosis(AIS). [Method]A total of 72 Lenke5 AIS patients were rescruited from May 1997 to October 2005.Out of them,40 received selective anterior fusion(group A) and 32 received selective posterior fusion(group B).All had a minimum of 2-year follow-up.[Result] No complication were found in both groups at the latest follow-up.The thoracic curve was corrected from 30° to 16° for group A,33° to 18° for group B.Both groups had a better spontaneous correction of the unfused thoracic curves.The correction rate had no significant difference between groups.However,the thoracic curve was increased in four patients(2 in each group;group C),which resulted in trunk imbalance.The thoracolumbar/lumbar thoracic(TL/L:T) Cobb's ratio averaged 1.09 in the four patients whereas 1.59 in other 68 patients(group D).The flexibility of the thoracic curve had significant difference in group C and D(34.2% vs 57.3%).[Conclusion]Both of the surgical treatments can get a better spontaneous correction of the unfused thoracic curves.It is important to evaluate the.thoracolumbar/lumbar–thoracic(TL/L:T) Cobb's ratio and the flexibility of the thoracic curve before selective fusion.