Selective posterior fusion of single thoracic curve adolescent idiopathic scoliosis: experience in 72 cases

Abstract

To prospectively evaluate the strategy of surgery and choice of the fusion segments in thoracic adolescent idiopathic scoliosis (AIS) treatment. Selective posterior fusion was used on 72 AIS patients, 13 male and 59 female, aged 14.3 (12 - 18), 50 being of Lenke-type IA, 8 Lenke-type IB, and 14 Lenke-type IC. In principle the upper neutral vertebrae were selected as upper instrumented vertebrae. The lower neutral vertebrae, the vertebrae 1 level proximal to the neutral vertebrae, or stable vertebrae were chosen as the lower instrumented vertebrae based on the analysis of the correlation among the lower end vertebrae, neutral vertebrae and stable vertebrae's locations. Standing anteroposterior and lateral and side-bending radiographs were taken preoperatively, postoperatively and during the follow-up. The coronal and sagittal Cobb angle, translation and rotation of apical vertebrae, and trunk translation were evaluated to observe the curve correction and trunk balance. The patients underwent spinal fusion of 7.3 segments (4 - 10 segments) on average. Follow-up was conducted for 15.9 months (12 - 39 months). The thoracic curves' coronal Cobb angle before the operation was 56.7 degrees +/- 14.5 degrees (40 degrees - 98 degrees), and was 18.5 degrees +/- 8.3 degrees (3 degrees - 40 degrees) after the operation. The lumbar curves' coronal Cobb angle before operation was 33.9 degrees +/- 10.4 degrees (25 degrees - 69 degrees), and was 11.1 degrees +/- 6.4 degrees (0 degrees - 30 degrees ) after operation. The spontaneous correction rate was 66.9% +/- 16% (44% - 100%). The trunk translation before operation was 16.1 +/- 10.2 mm (4 - 43 mm), and was 8.2 +/- 6.1 mm (0 - 25 mm) after operation. Two patients were found with slight trunk decompensation postoperatively, but with no progression during a 2-year follow-up. Determination of the fusion levels based on the analysis of the correlation among the end vertebrae, neutral vertebrae and stale vertebrae's location helps obtain the satisfying curative effect in the management of single thoracic curve AIS.