Retropharyngeal internal carotid artery: a review of three cases

The internal carotid artery (ICA) can take multiple pathways as it extends from the carotid bifurcation to the skull base. An aberration of its normal pathway may place the ICA in a retropharyngeal position in close proximity to the posterior pharyngeal wall. Radiographic classification is based on its proximity to the pharynx and/or pathway. We present a series of three cases of retropharyngeal ICAs, our goal is to report and classify these variations.

CASE 1: Retropharyngeal right ICA. Minimum distance to the pharyngeal wall was ~ 4.9 mm (high risk of vascular injury) with a tortuous pathway. CASE 2: Bilateral retropharyngeal ICA. ICAs were in contact with the posterior pharyngeal wall (very high risk of vascular injury). The left has a kinking pathway, the right tortuous. CASE 3: Bilateral retropharyngeal ICA. Minimum distances of the right and left ICAs to the posterior pharyngeal wall were ~ 3.5 mm and ~ 3.3 mm, respectively (high risk of vascular injury). The right has a kinking pathway, the left tortuous.

Closeness of the vessel to the retropharyngeal wall increases the risk of surgical and non-surgical complications. Noteworthy is that the position of the artery is not constant and can change in position over periods of time.

Knowledge of the anatomy and variations of the ICA is important for oral and maxillofacial radiologists and surgeons to enable clinicians to take necessary precautions to decrease complications if performing any procedure in the region.