Comparative evaluation of single-level closing-wedge vertebral osteotomiesfor 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 correc tion and change in anterior height and distance of the spinal column and to describe a modification of the decancellation closing-wedge osteotomy to o btain further correction. Summary of Background Data. Fixed kyphotic deformity of the lumbar spine ca n cause difficulty with sitting, lying flat, and pain and can pose a risk t o adjacent spinal cord and nerves as well as impair respiratory and abdomin al function. Various corrective osteotomies have been described. Osteotomie s involving decancellation and a closing wedge of the apical vertebra theor etically 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 conventi onal anterior opening-wedge/posterior closing-wedge osteotomy, Group 2 unde rwent a conventional decancellation posterior closing-wedge osteotomy, and Group 3 underwent our modified decancellation posterior closing-wedge osteo tomy. 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 Gro up 2, and 49 degrees for Group 3. The mean change in anterior height and di stance was 20 and 30 mm, respectively, for Group 1. For Groups 2 and 3 it w as only 2-4 mm. Conclusions. The authors recommend single-level posterior decancellation pr ocedures for correction of fixed kyphotic deformities of the thoracolumbar spine to decrease the risk to anterior neurovascular structures. An additio nal 10-13 degrees of correction can be obtained with the authors' modificat ion.