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.