Exposure of the internal carotid artery near the skull base: the posterolateral anatomic approach.

Internal carotid injuries in zone III near the base of the skull are technically the most challenging of the carotid injuries. Diagnostic angiography is important to evaluate the exact site and extent of injury and the presence or absence of prograde flow in the injured segment. Vascular repair in this area is highly dependent on the adequacy of surgical exposure. Previous approaches have emphasized displacement of the mandible either by subluxation or mandibulotomy. Problems related to mandibulotomy, such as intraoral contamination, infection, and nonunion, are potential complications of this approach to the high carotid artery. In addition, it does not give adequate exposure of the internal carotid artery at the critical area, near the base of the skull. Experience gained from the extended radical neck dissection exposing the internal carotid artery up to the skull base has demonstrated that a posterolateral anatomic approach can provide superior exposure of the high carotid artery with lower morbidity and shortened operative time. This surgical approach involves cutting the sternomastoid muscle close to the mastoid and dissecting all the tissues away from the surface of the mastoid. Dividing the posterior belly of the digastric and styloid group of muscles assists in exposure of the internal carotid artery. Rarely, dissection of the facial nerve and removal of the tail of parotid add additional access to this area. This article describes the stepwise anatomic approach to the internal carotid artery near the base of the skull.