Relation between patient positioning, trunk flexibility and surgical correction of the scoliotic spine

The purpose of this work is to investigate the relations between the correction of idiopathic scoliosis obtained by surgical instrumentation and the positioning of the patient on the surgical table as well as the curve reduction following the bending test. A retrospective study of preoperative standing, supine and lateral bending films as well as postoperative standing films was made using multiple regressions in order to identify the most significant parameters and define linear statistical models to predict the surgical correction. Postoperative thoracic Cobb angle is significantly associated to left and right bending Cobb angles and the post-op lumbar Cobb is associated to the supine and the left bending Cobb angles. This preliminary study suggests that such parameters should be considered in the pre-operative planning of surgery as well as in biomechanical models to obtain more adequate predictive values of the surgical outcome and to better understand the biomechanics of scoliosis surgical correction.