Os odontoideum: presentation, diagnosis, and treatment in a series of 78 patients.

OBJECT: The most contentious issue in the management of os odontoideum surrounds the decision to attempt atlantoaxial fusion in patients with asymptomatic lesions. The authors examined the clinical presentation and outcome in patients with os odontoideum who underwent surgical stabilization, with an emphasis on 3 patients who initially received conservative treatment and suffered delayed neurological injury.

METHODS: Seventy-eight patients (mean age 20.5 years; median 15 years) were identified in a 17-year retrospective review. The median follow-up period was 14 months (range 1-115 months). Neck pain was the most common symptom (64%), and 56% of patients presented after traumatic injury. Eighteen patients had neurological signs or symptoms at presentation, and an additional 15 had a history of intermittent or prior neurological symptoms. Fifteen patients had undergone > or = 1 attempt at atlantoaxial fusion elsewhere.

RESULTS: Seventy-seven patients underwent posterior fusion and rigid screw fixation combined with a graft/wire construct: 75 had C1-2 fusion and 2 had occipitocervical fusion. One patient had an odontoid screw placed. Fusion was achieved in all patients at a median of 4.8 months (range 2-17 months). Approximately 90% of patients had resolution or improvement of their neck pain or neurological symptoms.

CONCLUSIONS: The authors believe that patients with os odontoideum are at risk for future spinal cord compromise. Forty-four percent of our patients had myelopathic symptoms at referral, and 3 had significant neurological deterioration when a known os odontoideum was left untreated. This risk of late neurological deterioration should be considered when counseling patients. Stabilization using internal screw fixation techniques resulted in 100% fusion, whereas 15% of patients had previously undergone unsuccessful wire and external bracing attempts.