Vertebral Derotation in Adolescent Idiopathic Scoliosis

The treatment of adolescent idiopathic scoliosis has evolved substantially over the years. Early designs, such as the Harrington rod, corrected coronal deformity but failed to account for normal sagittal alignment. Cotrel-Dubousset instrumentation allowed for better control of sagittal contours such as thoracic kyphosis and lumbar lordosis while maintaining coronal deformity correction. However, rotational control of scoliosis remained poor. Modern instrumentation systems with pedicle screws allow for the first time the possibility of true rotational correction, but this requires more than simple rod derotation maneuvers. Instead, a method of directly applying rotational force to a screw that has 3-column purchase is required in order to effect a derotation of individual vertebra. This is accomplished through the advent of direct vertebral rotation devices. We describe the technique to use these devices to perform rotational correction of scoliotic deformities later in the text.