Anomalous Origin and Course of the Persistent Trigeminal Artery: A Cadaveric Study with Clinical Implications.

Abstract 

Background: The persistent trigeminal artery (PTA) is the most common among the persistent embryonic carotid-basilar anastomoses. While typically asymptomatic, its presence significantly alters intracranial hemodynamics and poses unique challenges during neurovascular interventions and skull-base surgeries. This study investigates the morphological characteristics and clinical relevance of PTA discovered during routine cadaveric dissection.

Materials and Methods: A comprehensive dissection of 40 formal-fixed human cadaveric heads was conducted at the Department of Anatomy. The cavernous and petrous segments of the internal carotid artery (ICA) were meticulously exposed to identify any anomalous communications with the vertebrobasilar system.

Results: A unilateral persistent trigeminal artery was identified in one male cadaver (2.5% incidence). The artery originated from the posterolateral aspect of the cavernous segment of the ICA. It followed a lateral course to the abducens nerve, pierced the dura mater near the trigeminal ganglion, and joined the superior third of the basilar artery between the origins of the superior cerebellar and anterior inferior cerebellar arteries. Notably, the ipsilateral vertebral and proximal basilar arteries were found to be hypoplastic, indicating a fetal-type circulation where the PTA served as the primary blood supply to the posterior fossa.

Conclusion: Knowledge of PTA is vital for neurosurgeons and interventional radiologists. Its proximity to the trigeminal nerve may explain cases of trigeminal neuralgia, while its role in posterior circulation must be recognized to avoid catastrophic ischemia during carotid endarterectomy or endovascular procedures. This study reinforces the necessity of vascular imaging prior to complex transsphenoidal surgeries.

Keywords: Persistent Trigeminal Artery, Anatomical Variation, Internal Carotid Artery, Basilar Artery, Neurovascular Surgery.