Endoscopic endonasal study of the internal carotid artery course and variations

Background: With the advance in endoscopic sinus surgery, more procedures are being performed to address challenging lesions and, of particular concern, those around the internal carotid artery (ICA). Despite the current progress in the understanding of endoscopic paranasal sinus anatomy, little information is available about the course and variations of the closely related ICA as seen endoscopically. In this study, we show an endoscopic analysis of the ICA course in a series of advanced endoscopic dissections. Methods: Ten cadaver heads (20 sides) have been endoscopically dissected. Using an extended approach, a wide sphenoidotomy has been performed as far laterally as the pterygoid base, The latter also has been drilled posteriorly and the ICA was fully exposed from its petrous part up to its termination below the anterior perforated substance of the brain. High-quality endoscopic pictures were produced by coupling the video images with a digital recording system. Results: The ICA course, landmarks, and segments have been defined and analyzed. The ICA was found to have a variable course that was well appreciated using the multiangled, magnified endoscopic view. The importance of such variation was established in relation to the nearby anatomic structures as well as possible lesions involving this area. Conclusion: The results of this study provide the endoscopic sinus and skull base surgeon with a better understanding of the endoscopic course and variations of the ICA. In experienced hands, such endoscopic orientation should allow safer as well as more effective management of closely related lesions.