Risk factors for decreased distance between internal carotid artery and pharyngeal wall

The risk of disastrous bleeding during pharyngeal surgery is increased in cases of an internal carotid artery (ICA) that is medially displaced due to its anomalous course. We attempted to assess the distance between the ICA and the pharyngeal wall (DIP) and to evaluate the predisposing factors associated with ICA variation.

The course of ICA was studied in 509 CT scans, and a retrospective chart review was performed. The course of ICA and DIP were evaluated at each level of the pharynx: nasopharynx (NP), oropharynx (OP), and hypopharynx (HP).

The mean DIP value was greatest (15.8±4.6mm) at NP, decreased at OP (15.8±4.6mm), and was shortest at HP (13.5±6.0mm). DIP was significantly shorter in females compared with males at all three pharyngeal levels. Age was inversely correlated with DIP at NP and OP. Tortuous ICA was most common (51.4%), followed by straight (41.2%), kinking (6.9%), and coiling (0.5%) types. DIP was longest in the straight type and decreased as the curvature of ICA increased. The most common ICA type differed between younger (<60 years; 56.2% having the straight type) and older groups (≥60 years; 66.2% having the tortuous type). Females older than 60 years displayed a higher incidence of kinking ICA compared with males.

Hypopharynx, old age, female gender, and tortuous or kinking ICA types were risk factors for a decreased distance between the ICA and the pharyngeal wall. Meticulous examination of the pharyngeal wall should therefore be performed prior to pharyngeal surgery in patients with these associated risk factors.