Reducible and irreducible os odontoideum in childhood treated with posterior wiring, instrumentation and fusion. Past or present?

BACKGROUND: The aim of the study was to evaluate the results of instrumented rod and wire fusion in children with craniovertebral junction (CVJ) instability and os odontoideum.

METHODS: We evaluated seven children (mean age 9.85 years) with Down and Morquio's syndromes and primary os odontoideum. X-ray, computerized tomography (CT) scan and magnetic resonance (MR) imaging of the CVJ showed reducible instability in all of the cases but one. All the children underwent surgical correction by means of posterior wiring, instrumentation, fusion and external orthosis. A posterior wiring technique was also utilized in the only child with irreducible preoperative atlantoaxial instability, which, however, proved to be reducible under general anesthesia.

FINDINGS: At maximum follow-up (observation range 28 to 106 months, mean 59.42 months), the clinical picture was improved in all the patients. The postoperative neuroradiological investigations demonstrated satisfactory bony fusion with neural decompression in all patients.

CONCLUSIONS: A wiring technique to correct atlantoaxial instabilities has been shown to be more relevant in these children with syndromic atlantoaxial dislocation and os odontoideum due to its simplicity, safety (continuous fluoroscopic assistance is not necessary and there is no risk of neuro-vascular injuries) and lower costs (no complex hardware devices; no neuronavigation systems are required). Preoperative irreducibility of the C1-C2 shift is not an absolute criterion for transoral decompression in children since os odontoideum can be reduced under general anesthesia.