From 1982 to 1987 we operated 14 patients with severe lumbar kyphosis which has been associated with Bechtrew's disease. Of these 7 were females and 7 males of the average age of 36 years (30-45). The mean follow-up was 6 years (ranging from 3 to 8 years) All patients were submitted to a functional surgery which consisted of osteotomy of the lumbar spine and reestablishmcnt of lumbar lordosis. Indications for and osteotomy of the lumbar spine were cases of : hudge lumbar kyphosis that were exposed to permanent osification changes of the spine and without signs of the evolution of the disease. Corrective osteotomy of the spine was done in a one stage surgical procedure. The level of osteotomy was L3-L4 in 9 patients. In the remaining 5 patients osteotomy was done at the level of L2 - L3. Size of the osteotomy ranged from 2.5 to 3 cm. 'The obtained correction was fixed by means of transpedicular plate, Zielke's system or ordinary wire in 10 cases. Infour cases osteotomy remained unfixed. Posto-peratively, patients were immobilized in plaster jackets which they had to wear at least one year. All the patients were submitted to a weak-up test. In all the cases and excellent deformity correction has been achieved. In three cases the following complications occured : partial neurological deficit which completely recovered after six months, paraplegia which partially recurred and one case with recurrence of the deformity.

Keywords: osteotomy, lumbar kyphosis, ankylosing spondylilis.