Joseph Y. Margulies, Lawrence I. Karlin, and Marc A. Asher

Goals of Treatment

To establish control and correction of the curve with less blood loss and shorter fusion levels.

Diagnosis/Indications for Surgery

Anterior apical overcorrection of idiopathic scoliosis is an accepted treatment for adolescent patients with thoracolumbar and upper lumbar scoliotic curves of 40 to 65 degrees.

Contraindications

Contraindications to anterior instrumentation include kyphosis above the planned level of instrumentation, and a compensatory thoracic curve that does not bend out to 20 degrees or less on a supine forced-bend film.

Advantages

It is preferable to do a posterior correction in some cases because it can utilize a shorter fusion section. The implant assembly is used as a correcting tool during surgery, and remains in the body as part of the fixation-stabilization mechanism until bone healing occurs.

Disadvantages

Stiff curves may require posterior facet joint resection or a different plan, such as anterior discectomy followed by posterior instrumentation.

Preoperative Planning

End vertebrae are selected on the basis of standard deformity radiographs, including 36-inch posteroanterior (PA) and lateral x-ray and right and left bends. The regional apex is determined on the standing x-ray. It is the most laterally displaced portion of the Cobb curve from a line joining the center of the Cobb end vertebral bodies. If the regional apex is a vertebra, further apparent as the single most rotated vertebra, the apex vertebra plus one vertebral body above and one vertebral body below are included in the fusion. As the scoliosis reaches approximately 55 degrees or greater, it is generally necessary to add two vertebrae above and two vertebrae below the apex vertebrae. If the regional apex is a disc, then two vertebral levels above and below the apex are fused. The first caudal disc space, which reverses coronal plane angulation on convex bending, can usually be excluded.

Procedure

The patient is positioned in a lateral decubitus position so that PA and lateral x-rays can be obtained. No bolster is placed under the patient as this has a tendency to block full correction. The usual anesthetic and padding precautions are necessary.