3-D Correction of Adolescent Idiopathic Scoliosis (AIS) With Differential Metals

Current posterior instrumentation devices employ pedicle screw and hook based systems to correct spinal deformity. Challenges remain for surgeons to appropriately contour the rods used to achieve the desired correction. The current practice is for the surgeon to intra-operatively contour the rod using various bending tools based on the appearance of the spine. The surgeon visually estimates the amount of bend needed and contours the rod accordingly. Changes in rod contours during implantation from the forces of correction limit the ability to achieve desired and optimal corrections. This is possibly related to both inaccurate bending estimates as well as techniques that affect the peri-implantation rod contours. These phenomena may lead to complications including but not limited to failure of hardware, coronal and/or sagittal spinal imbalance, and adjacent segment pathology or failure. The ability for the surgeon to pre-operatively calculate the proper bends to generate a predictable correction may improve patient outcomes by achieving better overall correction, better coronal and sagittal balance, reduce adjacent segment pathology.The purpose of this study is to evaluate the correction of adolescent idiopathic scoliosis deformity achieved utilizing a technique of differential rod bending with rod contours pre-operatively determined from a best-fit measure utilizing a computer-based software tool,Surgimap Spine to generate a template for manual rod contouring. The study will correlate the post-operative changes in rod contours with the correction achieved in spinal deformity. The pilot study will be used to validate the model for a prospective, randomized, multi-center, study of statistical power to compare the results of pre-operatively determined rod contours to intra-operatively determined rod contours