Rotation vector, a new method for representation of three-dimensional deformity in scoliosis.

Rotation vector for three-dimensional deformity, a new concept in scoliosis, is presented. This vector quantifies three-dimensional deformity in scoliosis. Rotation vectors are calculated between pairs of end plates. Any three-dimensional malalignments (scoliosis, lordosis [or kyphosis] and rotation) existing between a pair of end plates should be cancelled perfectly by rotating one end plate against the other about an axis represented by the rotation vector. A rotation vector suggests how the deformity in scoliosis should be corrected three-dimensionally.