Os odontoideum: Etiology, diagnosis, and management

BACKGROUND There have been few reports of os odontoideum since the initial description . METHODS Forty-four patients with os odontoideum treated during the period 1980 thro ugh 1996 were reviewed. There were 33 males and 11 females. Their ages rang ed from 7 to 56 years, with an average of 24.6 years. Five patients with no symptoms were treated conservatively. Thirty-nine patients underwent opera tive treatment including nine posterior atlantoaxial fusions and 33 occipit ocervical fusions. RESULTS The patients were followed up for one to 16 years, with an average of 6.5 y ears. Five patients treated conservatively have remained stable. All 39 tre ated patients achieved solid arthrodesis. The results were satisfactory. CONCLUSIONS We conclude that fusion is indicated if atlantoaxial instability or clinica l symptoms are significant, and that occipitocervical fusion should be cons idered in the operative management of os odontoideum if atlantoaxial arthro desis is impossible. (C) 2000 by Elsevier Science Inc.