Traumatic Peudoaneurysm of Internal carotid Artery

Pseudoaneurysm is an extra vascular hematoma that communicates with the intra vascular space where the vascular wall has been breached and the external wall of the aneurismal sac consist of only the outer arterial layer, perivascular tissue or blood clot.
ICA (Internal Carotid Artery) lesions are one of most serious and relatively frequent complication in all mechanisms of craniofacial trauma. Several clinical manifestations can occur as cerebral neurological deficit and cranial nerve palsies. Recurrent and massive epistaxis can occur after trauma due to pseudoaneurysm of external and internal carotid arteries.
Traumatic pseudoaneurysm of internal carotid artery (TPICA) pathogenesis involves partial vessel transaction and formation of hematoma. Unclotted portion of the hematoma surrounding the vessel is filled up by circulating blood and is in continuity with the arterial lumen. The blood causes an inflammatory reaction in surrounding tissue with the development of fibrous capsule and an epithelial lining. Continuous pulsatile pressure can result in enlargement, weakening and breakdown of the fibrous wall. Clinical presentation is usually delayed, recurrent well tolerated epistaxis to severe bleed with hemodynamic instability. Skull base TPICA can present with a classical triad of unilateral blindness, orbital fractures and recurrent epistaxis. CT and MRI provide initial information to suggest TPICA diagnosis and MR or CT angiography may confirm it however the gold standard investigation is conventional carotid angiography.
TPICA can be treated by surgery or endovascular interventions. They are either deconstructive in which the affected vessel is removed from the circulation or reconstructive, where the pseudoaneurysm is embolized but the circulation by the vessel is maintained. Endovascular treatment of the pseudoaneurysm can be done with coils, stents, covered stents and detachable balloons. Before occlusion of the parent artery (ICA) a balloon test occlusion (BTO) is carried out for thirty minutes to decrease the risk of ischemic complications. During the test the patient is observed clinically for any neurological deficit and angiographicaly to detect any compromise of cerebral circulation. Those who tolerate BTO without any neurological deficit can undergo parent artery occlusion and EC –IC (external carotid to internal carotid) bypass surgery performed in patients who are unable to tolerate BTO. However 5 – 22% of patients who pass the BTO develop ischemic complications.
Because the onset of TPICA bleeding from the time of injury is variable rapid recognition and treatment ensures the best outcome.(2)