Comparison of Vertebral Rotation Corrected by Different Techniques and Anchors in Surgical Treatment of Adolescent Thoracic Idiopathic Scoliosis

Summary: A comparative study of vertebral rotation in the correction of thoracic scoliosis by different surgical techniques and/or anchors, including hooks, wires and pedicle screws on the periapical concave side from a posterior approach, and an anterior approach using screws, was performed. Vertebral rotation in AIS is effectively corrected by either the anterior approach or posterior pedicle screw fixation, especially in patients whose scoliosis is flexible, compared with the use of hooks and wires.

Purpsoe: To compare the correction of vertebral rotation by different surgical techniques and/or anchors in the treatment of adolescent idiopathic scoliosis (AIS).

Materials and Methods. A retrospective study was performed on 106 consecutive patients (6 males and 100 females) with AIS who underwent a selective thoracic fusion with different surgical techniques and/or anchors, including hooks, wires and pedicle screws on the periapical concave side from a posterior approach, and an anterior approach using screws. The inclusion criteria were as follows: younger than 20 years old, thoracic scoliosis (Lenke type 1,2,3), selective thoracic fusion, a minimum two-year follow-up, excluding thoracic hyperkyphosis. The patients were classified into Group A (anterior approach, n=27), Group H (hooks, n=39), Group S (screws, n=25) and Group W (wires, n=15). Apical vertebral rotation was evaluated by CT (Aaro) before surgery, after surgery, and after 2 years of follow-up.

Results: All four groups were identical in the age, gender, pre-operative major curve, and curve flexibility. In all groups, the coronal Cobb angle was statistically significantly improved after surgery, without any significant differences among the four groups. The RAml values in Group A, Group H and Group S were statistically significantly improved after 2 years of follow-up (P<0 .01), whereas there was no significant difference in this value for Group W. RAsag significantly improved after 2 years A only. Classification of each group into two sub-groups according to the flexibility index (>0.5 and <0 .5) gave RAsag values that showed significant improvement post-operatively (P<0.01) for the Group A and S sub-groups with a flexibility index greater than 0.5.

Conclusion: Compared with the use of hooks and wires, vertebral rotation in AIS is effectively corrected by either the anterior approach or posterior pedicle screw fixation, especially in patients whose scoliosis is flexible (a flexibility index greater than 0.5).