Background: The branching patterns of the external carotid artery vary among individuals, and consideration of the proximity of nerves is important during catheter insertion in superselective intra-arterial infusion via the superficial temporal artery. We aimed to evaluate the anatomy of the external carotid artery and its surrounding nerves for safe and accurate administration of superselective intra-arterial chemotherapy via the superficial temporal artery.
Methods: We analyzed the external carotid artery and its branches morphometrically in 28 Japanese cadavers (56 sides).
Results: Vascular tortuosity in the preauricular region of the catheter insertion site was observed in 42.9% of the sides; the main trunk of the external carotid artery was excessively tortuous in 25.0% of the sides, primarily in the preparotid region. Faciolingual and superior thyrolingual trunks were observed in 28.6 and 1.8% of the sides, respectively. The superior thyroid, lingual, facial, occipital, and maxillary arteries branched from the external carotid artery above the carotid bifurcation in 41.1% of the sides. The mean distance between the insertion site and maxillary artery was 39.5 mm, indicating the extent of catheter insertion. The auriculotemporal nerve was observed near the superficial temporal artery in the preauricular region in 44.6% of the sides; however, the clearly identifiable nerves in the exposed area were difficult to avoid.
Conclusion: Because of the branching variations observed in individuals and sides, preoperative angiography is extremely important for avoiding complications.