The persistent trigeminal artery: development, imaging anatomy, variants, and associated vascular pathologies

Abstract

The persistent trigeminal artery (PTA) is the most common and most cephalad-located embryological anastomosis between the developing carotid artery and vertebrobasilar system to persist into adulthood. As such, it is frequently reported as an incidental finding in computed tomography angiography and magnetic resonance angiography studies. Here, we review the embryology, anatomy, and angiographic imaging findings, including important variants of this commonly encountered cerebrovascular anomaly (reported incidence of PTA/PTA variants ranges from 0.1% to 0.76%). Further, the aim is to present the range of associated arterial anomalies or syndromes, as well as pathologies that are associated with a PTA: aneurysms, trigeminal cavernous fistulas, and trigeminal nerve compression. Besides summarizing the risks and clinical presentation of such pathologies, their management is discussed with endovascular strategies mostly being the primary choice for aneurysms and trigeminal cavernous fistulas. Symptomatic trigeminal nerve compression can be treated with microvascular decompression surgery. As an illustrative example, a case of a trigeminal cavernous fistula on a PTA variant is included, mainly to emphasize the importance of understanding the variant anatomy for treatment planning in such pathologies. Finally, recommendations on how to manage patients with PTA-associated vascular pathologies are advanced.

Persistent trigeminal artery as a rare cause of ischaemic lesion and migraine-like headache

“…In patients undergoing vascular examinations, PTA and its variants are reported with a frequency of 0.1-1%, depending on the imaging modality used [3,17]. In early angiographic studies, the frequency of PTA in examined groups was approximately 0.2% [25]; however, in newer reports this number is significantly higher.…”

“…In rare cases PTA can contribute to cerebral stroke, which may be induced with thrombotic changes or steal syndrome [1]. The presence of PTA may also be associated with a higher likelihood of concomitant vascular pathologies, such as: arteriovenous malformations, carotid cavernous fistulas, moyamoya disease or abnormalities of the aortic arch and its branches [3,9,17].…”

RARE TRIPLE ANATOMICAL VARIATION OF THE CEREBRAL ARTERIAL CIRCLE; Rara triple variación del círculo arterial cerebral.

“…Moreover, in case of hypoplastic or occluded VA, the only endovascular access route to the BA and its branches would have been through ICA-PTA. Likewise, BA-PTA becomes an invaluable endovascular route to the anterior circulation in case of ICA occlusion (Meckel et al, 2013). During brain angiography, PTA was filled both after carotid and vertebral injection, allowing for bidirectional blood flow.…”

“…-A medial or sphenoid group, in which the artery arises from the posteromedial aspect of the cavernous ICA coursing medial to the abducens nerve, close or into the sella turcica, and pierces the dura of the dorsum sellae. Besides being exposed to iatrogenia during sellar surgery, this variation is associated with transient ischemic attack of the posterior fossa, with symptoms such as dizziness, vertigo, gait disturbance and ataxia (Salas et al, 1998 Meckel et al, 2013). Although early reports stated there was an association between PTA and other intracranial aneurysms, a large MR angiographic study over 16415 patients concluded there was no difference in intracranial aneurysms incidence among patients with and without PTA (O'uchi and O'uchi, 2010).…”

“…It has a major protective role over the arterial supply of the brain, allowing revascularization of one or more of the circle´s vessels through the remaining patent arteries. During fetal life, the development of four transient vascular channels connecting the fetal ICA with the longitudinal neural arterial plexus (which will later form the BA) takes place, ensuring blood flow to the cerebellum and brainstem during early fetal life (Meckel et al, 2013): the otic, hypoglossal, proatlantal and trigeminal arteries.…”