Correction of the kyphotic deformity in ankylosing spondylitis by Smith-Peterson technique or by posterior vertebral wedge osteotomy is possible by anterior opening of the vertebral column. However these methods carry risks of stretching major anatomical structures such as great vessels or cauda equina and sometimes may cause superior mesenteric artery to obstruct the intestine. In 1985 Thomasen described innovative procedure which consists of a posterior vertebral body decancellation. During this procedure the sponge bone of the vertebral body is removed along with the pedicles. A wedge fracture of L2 is created, producing lordosis and closing the wedge posteriorly. By this technique he could avoid major complications. Recently as we corrected a kyphotic deformity in ankylosing spondylitis by this technique and followed for 16 months that we report this case with review of the literature.