[Long-term prognosis of the hangman's fracture].

23 patients with traumatic spondylolisthesis of CII (hangman's fracture), all treated conservatively by external immobilisation and/or bed rest, were followed for an average of 9.6 years, 10 of them for 10-20 years. Radiographically two groups could be distinguished: one with bone formation between the vertebrae of CII and CIII and another without bone formation. Irrespective of the amount of bone formation their long-term prognosis was good: no new symptoms, old symptoms diminished and no limitation of neck movements. Degenerative changes in the neighbouring motor segments were not observed.