New guidelines for endoscopic localization of the anterior ethmoidal artery: a cadaveric study.

Objectives: To determine objective data to improve the methods of identification of the anterior ethmoidal artery during endoscopic dissection.

Study Design: Cadaveric dissection of adult human heads.

Methods: A 0 degrees, 4-mm rigid endoscope was used to guide uncinectomy and frontoethmoidectomy. The location of the anterior ethmoidal artery was first determined visually and then confirmed by passing a needle through the anterior ethmoidal foramen from the orbit into the nose in all cases. The distances were endoscopically measured using a simple ruler between two nasal landmarks and the anterior ethmoidal artery.

Results: Fifty-six nasal fossae in 28 cadavers were dissected endoscopically. The median distance between the artery and the "axilla" formed by the anterior attachment of the middle turbinate to the lateral nasal wall was 20 mm (range, 17-25 mm), irrespective of the side. The measurement differed by less than 2 mm between the sides in the same individual. The median distance between the artery and the "axilla" formed by the medial and lateral crura of the lower lateral cartilage (superomedial edge of the nostril) was 62 mm (range, 55-75 mm) for both sides. The artery was found to be in direct alignment with the two "axillae" formed by the middle turbinate and the nostril edge.

Conclusions: The distance between the ethmoidal artery and the axilla of the middle turbinate showed the least intraindividual and interindividual variations. The tip of the endoscope (or the ruler) points directly at the anterior ethmoidal artery in the fovea ethmoidalis when its edge is aligned with the two nasal landmarks. These simple guidelines can aid the identification of the artery in endoscopic frontoethmoidectomy.