Comparative evaluation of single-level closing-wedge vertebral osteotomies for the correction of fixed kyphotic deformity of the lumbar spine - A cadaveric study

Study Design. Anatomic study. Objectives. To compare spinal osteotomies with respect to obtainable correction and change in anterior height and distance of the spinal column and to describe a modification of the decancellation closing-wedge osteotomy to obtain further correction. Summary of Background Data. Fixed kyphotic deformity of the lumbar spine can cause difficulty with sitting, lying flat, and pain and can pose a risk to adjacent spinal cord and nerves as well as impair respiratory and abdominal function. Various corrective osteotomies have been described. Osteotomies involving decancellation and a closing wedge of the apical vertebra theoretically decrease the risk to anterior vascular structures. Methods. Single-level vertebral osteotomies were performed on three groups of fresh-frozen human cadaveric lumbar spines. Group 1 underwent a conventional anterior opening-wedge/posterior closing-wedge osteotomy, Group 2 underwent a conventional decancellation posterior closing-wedge osteotomy, and Group 3 underwent our modified decancellation posterior closing-wedge osteotomy. Sagittal plane angulation as well as anterior height and distance of the spinal column were measured before and after osteotomy. Results. The mean correction was 38 degrees for Group 1, 36 degrees for Group 2, and 49 degrees for Group 3. The mean change in anterior height and distance was 20 and 30 mm, respectively, for Group 1. For Groups 2 and 3 it was only 2-4 mm. Conclusions. The authors recommend single-level posterior decancellation procedures for correction of fixed kyphotic deformities of the thoracolumbar spine to decrease the risk to anterior neurovascular structures. An additional 10-13 degrees of correction can be obtained with the authors' modification.