Microsurgical anatomy of the internal carotid artery at the skull base

The aetiology and significance of internal carotid artery variations at the skull base remain controversial after decades, with limited available literature. Approximately 10-40 per cent of the general population has parapharyngeal internal carotid artery variations. A prospective observational study was conducted on internal carotid artery variations in 36 cadavers, in a tertiary care hospital, between March 2019 to March 2020. The most common internal carotid artery variation observed in the specimens was tortuosity, in 30 per cent, followed by kinking in 18 per cent and coiling in 10 per cent. Thirty per cent of specimens had variations present bilaterally. A loop pattern of the internal carotid artery was identified. Coiling of the internal carotid artery may present as a node; hence, meticulous dissection is advocated near the skull base to avoid complications. These variations hold utmost importance for otorhinolaryngologists performing pharyngeal and nasopharyngeal surgical procedures. A detailed knowledge of anatomy, along with its variations, and surgical expertise, will help reduce the incidence of surgical complications.