Rib deformity in scoliosis.

Rib deformity in scoliosis is of interest because it may help in the diagnosis, and also, in some pronounced cases, it may need correction by costoplasty. There are, however, debates about its use in diagnosis, because some authors think that rib deformity is not closely related to either the magnitude or the extent of rotation of the curve. In order to define the relation between rib deformity and scoliosis, 11 patients were recruited who were to undergo scoliosis surgery and thoracoplasty, and anteroposterior (AP) T1-S1 standing radiographs, computerized tomography (CT) scans, and three-dimensional (3D) reconstructions were obtained. From the radiographs, the most rotated vertebra, the Cobb angle, the apex and the type of the curve were determined. From the CT scans and 3D reconstructions, the exact level of the rib deformity measured was matched with the corresponding vertebral level. In this way, the most rotated vertebra and the most prominent part of the rib cage deformity were identified. The most rotated vertebra was found to be at the same level in both radiographs and CT scans in only five patients. In the rest of the patients, CT scans showed it either one level higher or lower than it appeared on the radiograph. The most prominent part of the rib cage deformity was at the same level as the most rotated vertebra in two patients, and in the rest of the patients it was one, two or three vertebral levels lower. There was no association between the Cobb angle, vertebral rotation and rib deformity. A CT scan is necessary preoperatively in patients who will undergo a costoplasty, to determine the exact levels of the prominence. However, a scanogram or a 3D reconstruction is required for exactly matching the most prominent part of the rib cage deformity to the corresponding vertebral level.