The retropharyngeal internal carotid artery
A pooled and topographic synthesis of a clinically important cervical ICA variant in which the artery approaches or abuts the pharyngeal wall, narrowing the safety margin for airway, transoral, cervical, and spine procedures.
RP-ICA is uncommon, but the procedural consequence can be major.
Five imaging cohorts contributed 150 cases among 10,066 adults. The pooled prevalence was 1.51%, but heterogeneity was substantial because definitions, modalities, and eras differed.
Five cohorts, very different estimates
The study-specific prevalence ranged from 0.07% to 7.97%, producing substantial heterogeneity.
Adults pooled
Patient-level denominator across five imaging cohorts.
RP-ICA cases
Patient-level numerator used in the meta-analysis.
I²
Marked heterogeneity across cohorts.
Study range
Definitions and imaging strategies strongly influenced estimates.
The clinically meaningful variable is distance to the pharyngeal wall
RP-ICA is most often described at the oropharynx. The artery may lie only a few millimetres from the mucosa or even contact it.
Oropharyngeal predominance, but the spectrum is broader
The review places RP-ICA within a broader retropharyngeal carotid spectrum that can also involve the CCA and, less often, the ECA.
Nasopharynx
Medialised carotids can approach the torus tubarius, pharyngeal recess, and posterior nasopharyngeal wall.
Oropharynx
The most frequently reported RP-ICA level and the key corridor for tonsillar and transoral risk.
Laryngopharynx
Medialised carotid segments can extend inferiorly and interact with hyoid-related and cervical-spine anatomy.
The carotid position may change over time
Serial imaging studies showed that retropharyngeal carotid position is not always fixed, which limits the value of remote pre-procedural imaging.
Positional change
One serial-imaging cohort documented carotid position change between studies.
Original case 1
Unilateral right retrotonsillar RP-ICA at C2–C3.
Original case 2 · left
Bilateral RP-ICA; right CPD 6.26 mm and left CPD 3.63 mm.
Where this anatomy matters most
A near-mucosal or submucosal ICA can turn routine procedures into vascular-risk procedures.
Airway management
Nasotracheal intubation and traumatic pharyngeal instrumentation can endanger a medially displaced ICA.
ENT / transoral surgery
Tonsillectomy, transoral robotic surgery, and related procedures require awareness of a reduced mucosal safety margin.
Spine surgery
Medialised carotids may enter anterior cervical operative corridors.
Dentistry / maxillofacial care
Cross-sectional imaging can reveal hazardous carotid proximity relevant to deep pharyngeal procedures and injections.