Images in Neurosurgery

Os odontoideum treated with posterior C1-2 fusion

A 58-year-old male was an unrestrained driver in a high-speed tractor accident who presented to our emergency room with upper extremity paresthesias and pain in the craniocervical region. On physical examination, he had normal strength in both upper and lower extremities, but he was hyperreflexic with a Hoffman’s sign in both upper extremities. CT of the cervical spine demonstrated an abnormality called os odontoideum (Figure 1, arrow, sagittal [A] and coronal [B]). An os odontoideum is a craniovertebral abnormality in which a smooth, well-corticated odontoid process is separated from the C2 body by an obvious gap. MRI of the cervical spine demonstrated a spinal cord contusion on T2-weighted imaging (Figure 2A, arrow) and hyperintensity in the transverse ligament on short tau inversion recovery (STIR) imaging (Figure 2B, arrow), which is a sign of acute ligamentous injury. A dynamic x-ray of his neck (Figure 3) demonstrated atlantoaxial instability on flexion and extension. We performed a posterior C1-2 fusion using Harms technique followed by a C1 laminectomy (Figure 4). He wore a cervical collar postoperatively for six weeks. At last follow-up six months later, he had returned to work and reported complete resolution of neck pain and paresthesias.

Submitted by: Rimal H. Dossani, MD, Lane Fontenot, BS, MS, Brian Willis, MD
Affiliations: Louisiana State University Health Sciences Center, Shreveport, Louisiana Department of Neurosurgery

CT of the cervical spine with os odontoideumMRI of the cervical spine with a spinal cord contusionDynamic x-ray of the neck

C1-2 fusion using Harms technique