The Internal Carotid Artery as it Relates to Endonasal Sphenoethmoidectomy

Abstract

A better understanding of the pathogenesis of chronic sinus disease has led to an increased performance of endonasal sphenoethmoid surgery. Approaching the sphenoid sinus via this route mandates that the surgeon be aware of the anomalies which may be encountered in this region, if injury to the related neurovascular structures is to be avoided. This study was therefore undertaken to evaluate a critical anatomic variation, the incidence of bony dehiscence over the carotid artery. Following cadaver sphenoethmoidectomy, the lateral wall of the sphenoid sinus was examined endoscopically and gently palpated in 188 sphenoid sinuses. An apparent dehiscence of bone was found over the carotid artery in 41 sinuses (22%), a significantly higher incidence than reported in other studies. In 3 specimens the carotid artery was exposed in the posterior ethmoid sinus. The study highlights the importance of considering this anatomic variation and of careful evaluation of the patient's computed tomographic scan, before this kind of surgery is attempted. Management of injury to the internal carotid artery in this area is also discussed.

Anatomical variations in the human paranasal sinus region studied by CT

“…Although we have found a constant asymmetry between both cavities of the sphenoid sinus, the identification of an asymmetric intersphenoid septum is very important especially when it shows a considerable deviation, as its advance marks the line of the internal carotid artery, which may protrude into the posterior ethmoid cells (Kennedy et al 1990). …”

Study of Sphenoid Sinus Anatomy in Relation to Endoscopic Surgery

“…Inspite of the complex anatomy and important surgical relationships of the sphenoid sinus, a very few recent reports focus on it (Lang, 1989;Kennedy et al, 1990;Sethi et al,.1995 ;Elwany et al, 1983 and. No such study has been reported from the Indian subcontinent.…”

Rare and Other Notable Complications in Endoscopic Sinus Surgery

“…8 Others have suggested a dehiscence rate as high as 22%. 9 Injury to the carotid can be from a laceration with immediate massive hemorrhage, pseudoaneurysm formation with delayed hemorrhage, or present with neurologic changes Box 10 Experience with management of this drastic although rare complication comes from the endoscopic skull base literature, where extended skull base approaches can have rates of ICA injury of around 5%. 11 First and foremost, it is critical to adequately and thoroughly review all imaging and specifically check for carotid dehiscence before performing surgery near the sphenoid.…”