Three-dimensional analysis of formation failure in congenital scoliosis.

Study Design. Morphologic analysis was performed by 3-dimensional (3D) CT in 75 patients with congenital scoliosis exhibiting formation failure. Objectives. The objectives of this study were to conduct 3D analysis of the morphology of spinal malformation and to elucidate the association between malformed vertebrae and adjacent vertebrae. of Background Data. The morphology of spinal malformation has conventionally been evaluated by plain radiograph radiography. Although the usefulness of 3D CT has recently been reported, these reports have only demonstrated that this technique allows more detailed evaluation than plain radiography. Methods. We examined the morphology of the posterior components in spinal malformation of formation failure and evaluated the association between the anterior and posterior components by 3D CT. We clarified the morphologic variations of the posterior components in spinal malformation by dividing 75 cases of formation failure into solitary and multiple numbers of malformed vertebrae and into simple and complex modes of malformation between anterior and posterior components. Results. Thirty-three patients exhibited a single malformed vertebra in the entire spine (solitary malformation group), while the other 42 had multiple malformed vertebrae (total, 102 malformed vertebrae: multiple malformation group). The multiple malformation group consisted of 26 patients (57 malformed vertebrae) in whom the cause of scoliosis could be explained separately for each of the malformed vertebrae and 16 patients (45 malformed vertebrae) in whom the structure was complicated and the cause of scoliosis could not be explained for each of the malformed vertebra. Conclusion. There were morphologic variations of the posterior components of malformed vertebrae. A completely new complex malformation in which the mechanism of formation failure may differ from the conventionally proposed mechanisms was also found.