Polysegmental lumbar osteotomies and transpedicled fixation for correction of long-curved kyphotic deformities in ankylosing spondylitis. Report on 177 cases.

Despite conservative therapy in ankylosing spondylitis, kyphotic deformities are common. Mono-segmental lumbar osteotomy had a high complication rate. Therefore, a poly-segmental lordosis osteotomy of the lumbar spine was introduced in four to six segments using trans-pedicled screws and threaded rods in eight to ten segments (isolated correction is possible for each segment). Instead of dangerous short kinking, a poly-segmental lordosis osteotomy results in harmonious lordosis with a correction per segment of about 10 degrees, and complications are decreased. Of 177 patients undergoing the operation, there was a 2.3% mortality rate with cardiopulmonary problems, 2.3% with irreversible complications, and 18.1% with reversible complications, mostly small root lesions, of which 7% were reoperated. The 173 surviving patients had a correction of 43%, and improvement in body height of 9 cm, and improvement of flexion by 57%. Fifty-three patients have been followed for more tha 18 months. the visual axis in all cases was horizontal. No pseudoarthrosis occurred. After correction, the frequent spondylodiscitis healed. Ninety-two percent were pain free compared with 15% before the operation. Loss of correction of body height was 20%, of flexion 4%, and of the lordosis 7%, which was 18% in 37 patients after three years.