Case 8
History:
35 year old male with headaches
Findings:
There is a vessel extending from the cavernous portion of the right internal carotid artery, traversing the sella and connects to the basilar artery.
Diagnosis:
Persistent trigeminal artery
Discussion:
During fetal development (approximately 35 gestational days) the craniocerebral circulation is characterized by temporary connections between the primitive carotid and the paired dorsal longitudinal neural arteries (precursors of the vertebro-basilar system) appear. They include persistent trigeminal, ottic, hypoglossal and proatlantic intersegmental arteries.
Persistent trigeminal artery (PTA) is the most frequent (85 percent) of these primitive carotid -basilar anastomoses. These also include the sphenoidal (medial) variant documented with hyper prolactinemia arising out of compression of pituitary gland and stalk. The petrosal (lateral) variant precipitates isolated VI nerve palsy. The lateral TA arises from distal precavernous or proximal cavernous ICA. The basilar artery is often hypoplastic. The medial TA arises from cavernous portion of ICA and courses through the sella.
The instance under report is considered a petrosal variant where the PTA compressed and distorted the nerve REZ of the trigeminal nerve, precipitating the facial pain syndrome. The other associations of PTA include aneurysm, internal carotid occlusions and vascular steal phenomena between basilar and carotid systems.
