Surgical Treatment for Odontoid Fractures in Patients with Long-Standing Ankylosing Spondylitis: A Report of 3 Cases and Review of the Literature

Background Ankylosing spondylitis (AS) is classified as a chronic inflammatory seronegative rheumatic arthritis. Patients with AS are more likely to sustain a fracture of the cervical spine compared with the general population. Most fractures occur in the lower cervical spine and manifest at the level of the intervertebral disc. There have been few reports about the surgical treatment for upper cervical spine fractures in patients with AS, especially odontoid fractures. We present 3 cases of odontoid fracture in patients with long-standing AS. Methods Odontoid fracture with atlantoaxial displacement was identified on radiologic imaging in 3 patients. In 1 patient, fracture was a missed diagnosis after initial trauma, and the fracture and displacement were discovered 3 months later owing to aggravation of symptoms. Posterior occipitocervical fusion with iliac autograft was performed under general anesthesia in all cases. Results All 3 patients recovered postoperatively without any complications related to surgery. Cervical radiographs obtained at 12-month follow-up demonstrated healed fracture and replacement of the atlantoaxial joint. Conclusions Odontoid fracture with atlantoaxial dislocation in patients with long-standing AS is uncommon. Clinicians must be cautious in assessing such patients with any episode of trauma. Computed tomography and magnetic resonance imaging can be helpful in demonstrating occult odontoid fractures. Posterior occipitocervical fusion with internal fixation may benefit these patients, although at the cost of sacrificing the last motion segment.