[A comparative study on the surgical outcomes of spinal fusion in adolescent idiopathic scoliosis patients with or without triradiate cartilages closed].

OBJECTIVE

To investigate the effect of potential spinal growth on the posterior-only spinal instrumentation of adolescent idiopathic scoliosis (AIS).

METHODS

From June 2003 to October 2007, 40 patients received posterior-only spinal instrumentation. Group of open triradiate cartilage (Group A) included 16 female AIS patients with mean age of 11.8, and group of closed triradiate cartilages (Group B) covered 24 female AIS patients with mean age of 13.7. The mean preoperative Cobb angles of Group A and B were 53.3° and 49.6° respectively, and the mean kyphosis in the sagittal plane was 27.7° and 27.8° respectively.

RESULTS

The post-operative Cobb angles were 22.2° (Group A) vs. 20.7° (Group B) (P = 0.34) with correction rate of 58.3% (Group A) vs. 57.7% (Group B) (P = 0.83). The mean Cobb angles at final follow-up were 24.8° (Group A) vs. 21.1° (Group B) (P = 0.05) with the correction loss of 5.3% (Group A) vs. 1.0% (Group B) (P = 0.01). In the sagittal plane, the average post-operative kyphosis was 22.5° (Group A) vs. 23.9° (Group B) (P = 0.49) with correction of 5.2° (Group A) vs. 3.9°(Group B) (P = 0.63). The mean kyphosis at final follow-up was 20.8°(Group A) vs. 24.7°(Group B) (P = 0.04) with the correction loss of -1.7° (Group A) vs. 0.8°(Group B) (P = 0.01). Group A showed obvious correction loss in the coronal plane and decrease of kyphosis in the sagittal plane. Adding on phenomenon was found in 2 cases with Lenke type I with selected fusion in Group A, but not in Group B.

CONCLUSIONS

Although similar post-operative correction is found in AIS patients with OTRC or CTRC, the loss of correction and "adding on phenomenon" are more likely to happen in patients with OTRC.