Exposure of the External Carotid Artery Through the Posterior Triangle of the Neck: A Novel Approach to Facilitate Bypass Procedures to the Posterior Cerebral Circulation

Abstract

Background: The external carotid artery (ECA) is the main high-flow donor for extracranial-intracranial revascularization procedures. However, anatomic restraints limit the availability of ECA in posterior exposures of the craniocervical junction aimed for bypass to distal vertebral artery segments.

Objective: To examine the feasibility and safety of exposure of the ECA through the posterior triangle of the neck.

Methods: A preliminary feasibility study on the posterior neck exposure of the ECA was performed in 1 cadaveric head (2 sides) followed by a morphometric study on 9 cadaveric heads (18 sides). Through an extension of the muscular stage of the far-lateral approach, the fascial plane between the posterior belly of the digastric muscle and the capsule of the parotid gland was dissected inferior to the C1. Topographic anatomy of the exposed distal segment of the ECA was defined in detail, including bony landmarks and the facial nerve.

Results: ECA was found successfully using the proposed technique in all specimens. In 90% of the specimens, ECA was exposed without transgression of the capsule of the parotid gland. The facial nerve was not encountered during the surgical exposures.

Conclusion: ECA can be safely and effectively exposed through the posterior triangle of the neck using the proposed approach. This method can facilitate extracranial-intracranial bypass procedures to V3/V4 vertebral artery. Advantages of this novel approach are shortening the graft length and surgical timing, less invasiveness, and optimizing surgical trajectories for completion of both donor and recipient bypass anastomosis.

Keywords: Bypass; Cerebral revascularization; Digastric muscle; Facial nerve; Far-lateral approach; Parotid gland; Vertebral artery.