A Progressive Anatomic Algorithm for Transcervical Approaches to the Internal Carotid Artery at the Skull Base: A Comparative Anatomic Study

Background: Open surgical approaches to the internal carotid artery (ICA) have been well described including extended transcervical approaches and variations of the infratemporal fossa approach. From the carotid artery bifurcation to its entrance into the carotid canal, a multitude of benign and malignant pathology can often involve the ICA requiring meticulous dissection and progressive surgical approaches. However, though the operative approaches to the ICA have been described, direct comparisons of the surgical exposure attained with various open operative techniques has not been studied. In this cadaver study, we strive to demonstrate the operative techniques, surgical limits, and amount of ICA exposure gained through a progressive series of operative dissections and present an anatomical algorithm that will be useful when choosing the most ideal surgical approach depending on the nature and extent of the pathology.

Methods: Six, latex-injected adult cadaver heads were dissected in the following five consecutive approaches: transcervical approach with submandibular gland removal, posterior extension of the transcervical approach, transcervical approach with parotidectomy, parotidectomy with lateral mandibulectomy, and transcervical/parotidectomy with mandibulectomy. In each of these approaches, progressive measurements of the amount of ICA exposure attained was measured with a 10-cm surgical ruler.

Results: In all surgical approaches, measurements were made from the carotid artery bifurcation to the superior limit achieved. In the initial transcervical approach with submandibular gland removal, the distance of ICA visualized was 1.5 cm (SD, 0.5). With the posterior extension of the transcervical approach, 2.9 cm (SD, 0.7) of ICA exposure was visible. With the parotidectomy, an additional 0.8 cm of visualization was achieved for a total of 4.0 cm (SD, 1.0) of ICA visualized from the bifurcation. On releasing the angle of the mandible via a mandibulectomy, a total of 4.6 cm (SD, 1.2) of the ICA from the carotid bifurcation could be visualized and accessed directly. Finally, with a mandibulectomy, 6.9 cm (SD, 1.3) of the ICA from the carotid bifurcation to its superior limit at the carotid canal could be directly approached.

Conclusion: Through progressive dissection, we were able to demonstrate variations in exposure of the ICA through open surgical techniques. By understanding the limits of surgical exposure attained, decisions regarding the best surgical approach with the least morbidity while maximizing exposure required for intended pathology can be made. Through these cadaveric dissections, we present an anatomical algorithm for approaching the ICA through open surgical corridors.