17 Surgical Treatment of the Right Thoracic Curve Pattern

Abstract

The right main thoracic (MT) curve pattern is the prototypic scoliotic deformity seen in adolescent idiopathic scoliosis (AIS), being found in almost 50% of all cases treated surgically. By definition, the MT curve in AIS has an apex between T2 and T11, and has the largest coronal deviation of any of the curves in this condition as measured by the Cobb-angle method. Measuring apical deviation, relative apical lordosis, and transverse-plane rotation provides a further means of describing the major curve and captures some of the three-dimensional (3D) nature of this deformity that is lost in the largely two-dimensional (2D) imaging of it. Characteristics of the minor curves proximal and distal to the MT curve are as important as the features of the 3D thoracic deformity. Many of the decisions to be made in the treatment of MT curves depend on these minorcurve characteristics. Understanding how minor curves will "respond" to surgical correction of the MT curve is critical in the treatment of scoliosis. This chapter addresses the characteristics of the right MT curve pattern in AIS and discusses the criteria used to decide when and how to address this spinal deformity. Options for selective versus nonselective fusion are discussed, as are the surgical approaches currently used for the correction of right MT curves. Specifically, the particular indications and contraindications for each approach are evaluated, and recommendations are made for surgical technique and for the selection of fusion levels in correcting such curves.