Management Issues in a Case of Congenital Craniovertebral Junction Anomaly with Aberrant Retropharyngeal Midline Course of Bilateral Cervical Internal Carotid Arteries at C1-C2.

Background: Aberrant medial retropharyngeal prevertebral course of the internal carotid arteries (ICAs) is extremely uncommon. In oropharyngeal surgeries, like transoral odontoidectomy (TOO), this unrecognized aberrant retropharyngeal course of ICAs can result in devastating complications secondary to inadvertent injury of ICAs. We describe this aberrant course of ICAs in a patient with a craniovertebral junction (CVJ) anomaly with a dysmorphic C1 lateral mass on one side and discuss in detail various management issues in this complex case.

Case Description: A 44-year-old patient presented with neck pain, paresthesia in all 4 limbs, and quadriparesis. Computed tomography (CT) of the CVJ revealed os odontoideum, basilar invagination, atlantoaxial dislocation (AAD), severe malalignment of the C1-C2 facets, and an unusually thin (dysmorphic) left C1 lateral mass. Computed tomographic angiography revealed an aberrant medial retropharyngeal course of the bilateral cervical ICAs with near midline location at the level of C1 and C2. Transoral odontoidectomy (TOO) was not considered safe in view of potential injury to medially located ICAs. Normal spinal alignment with reduction of BI and AAD was achieved by C1-C2 joint distraction with placement of a spacer only in the right C1-C2 joint space followed by occipitocervical fusion. The patient experienced complete recovery after surgery with improvement of power in all 4 limbs to 5/5.

Conclusions: Identification of this rare aberrant prevertebral course of ICAs in a patient with a CVJ anomaly is critical because it precludes TOO as a treatment option. Correction of BI and AAD is possible even with a unilateral C1-C2 joint spacer when placement of a joint spacer on the other side is not technically feasible.