Bending Radiographs as a Predictive Factor in Surgical Correction of Adolescent Idiopathic Scoliosis

OBJECTIVE To evaluate the use of x-rays in dorsal decubitus, as a predictive factor for surgical correction of the main thoracic curve using pedicle screws, on patients with idiopathic adolescent scoliosis. METHOD Twenty patients with idiopathic adolescent scoliosis of Lenke types 1A and 1B who were operated using a technique only involving pedicle screws by means of the posterior route were evaluated clinically and radiographically. The curve flexibility was calculated by means of active supine lateral oblique radiographs. The postoperative values for the main thoracic curve were included in a mathematical equation proposed by Cheung et al., with the aim of predicting the expected angular result from the surgical correction. The difference between the expected and actual postoperative results was then investigated regarding its statistical significance. RESULTS There was statistical significance for all the cases studied, between the values predicted before the operation and the radiographic findings immediately after the operation (p < 0.005). CONCLUSIONS It is possible to predict the percentage surgical correction of the main thoracic curve that will be achieved using pedicle screws in patients with idiopathic adolescent scoliosis of Lenke types 1A and 1B, by means of preoperative supine oblique radiographs.