Retropharyngeal internal carotid artery: a potential risk factor during nasotracheal intubation

Purpose To investigate the potential risk of the retropharyngeal internal carotid artery (RICA) during nasotracheal intubation (NTI). Methods We retrospectively surveyed 2028 patients and 90 healthy controls (HC) with neck computed tomography angiography (CTA). The incidence of RICA was analyzed, as well as the correlation between the average minimum carotid-pharyngeal distance (CPD) and the carotid-median plane distance (CMD). We also compared CPD between RICA and HC. Results RICA was observed in 91 out of the 2028 patients, reaching an incidence of 4.5% (91/2028). RICA in female patients was 65.9% (60/91) compared to 34.1% (31/91) in male patients. The incidence of RICA at nasopharynx (NP), oropharynx (OP), and hypopharynx (HP) was 31.9% (29/91), 61.5% (56/91), and 6.6% (6/91), respectively. The incidence of the mucosal eminence of the posterior wall of the pharynx in RICA was 30.8% (28/91). In 15 cases, RICA caused the pharyngeal cavity to become narrow, with an incidence of 16.5% (15/91). Moreover, CPD and CMD was positively correlated (r = 0.56, p < 0.01). The average minimum CPD of RICA was only 2.25 +/- 1.26 mm, which was much shorter than HC (17.62 +/- 1.98 mm) (t = 62.46, p < 0.01). Some CPD of RICA was even less than 1 mm, with an incidence of 20.9% (19/91). Conclusion RICA is not uncommon in asymptomatic adults. It is very close to the midline and posterior wall of the pharynx and is more likely to occur in the nasopharynx (NP) and oropharynx (OP). RICA tear is likely to occur during NTI.