Eleven patients with ankylosing spondylitis had severe disabling kyphosis with forward bending of the upper part of the spine. The kyphosis was corrected by osteotomy by removal of a wedge composed of the spinous processes and the neural arch of the second lumbar vertebra and by excision of bone from the inside of the posterior part of the vertebral body of L2. By hyperextending the spine, a wedge fracture occurs in the vertebral body, producing lordosis and correction of the deformity without an anterior opening of the lumbar discs.