A prospective comparison of surgical outcomes of two different surgical techniques in correcting thoracic adolescent idiopathic scoliosis

Abstract

INTRODUCTION: The “X-Factor Index” (i.e. extraneous factors that may affect curve correction) has recently been introduced to complement the Fulcrum Bending Correction Index (FBCI) in reflecting the true corrective ability for adolescent idiopathic scoliosis (AIS) surgery. Our study assessed the outcome of two surgical techniques and to determine the contribution of surgical technique to the X-Factor Index. METHODS: Fifty-four patients (85% females; mean age: 12 years) with thoracic AIS underwent posterior spinal fusion with instrumentation using two different techniques, by two different surgeons, without direct apical derotation but similar pedicle screw fixation strategy, were prospectively assessed. In technique A (n=25), after locking only the distal most pedicle screw on the concave side, curve correction was achieved from the convex side using the differential rod contouring technique. In technique B (n=29), the deformity correction was achieved from the concave side. The FBCI was used to compare the correction achieved. RESULTS: The median FBCI for groups A and B were 112.1 and 128.3, but did not significantly differ (p=0.278). When curve flexibility was overall greater than 50%, individuals in Group B (median, 123.8) had more curve correction than Group A (median, 109.4) (p=0.030) but this finding was not noted in individuals with higher flexibilities (e.g. 60 % and greater). CONCLUSION: The corrective ability of thoracic AIS depends to a degree on the inherent flexibility of the curve. Although there were suggestions that surgical technique may improve curve correction, statistical significance was not noted. However, larger studies are needed for further validation.