Persistent primitive hypoglossal artery associated with Chiari II malformation: Diagnosis and clinical implications

Unusual case of persistent primitive hypoglossal artery with anterior choroidal artery aneurysm in Chiari type I malformation

Persistent primitive hypoglossal artery (PPHA) is a rare form of persistent embryonic carotid-basilar anastomosis. We present an unusual case of PPHA and an anterior choroidal artery (AChoA) aneurysm associated with Chiari type I malformation. A 45-year-old woman presented with transient dizziness. Magnetic resonance imaging revealed Chiari type I malformation and a left AChoA aneurysm. Digital subtraction angiography incidentally revealed a left PPHA. To the best of our knowledge, this is the first reported case of Chiari malformation in conjunction with PPHA and aneurysms. In this case, the perfusion of the posterior circulation is completely dependent on PPHA. It is very important to identify such variant vessels and complex angioarchitecture before planning neuroendovascular or surgical intervention to prevent possible risks.

Fatal Subarachnoid Hemorrhage from an Aneurysm of a Persistent Primitive Hypoglossal Artery: Case Series and Literature Overview

BACKGROUND

Persistent carotid-basilar connections have a prevalence of 0.14%. Recognizing such persistent fetal anastomoses between the carotid and the vertebrobasilar circulation is of great importance because they are reportedly associated with an increased prevalence of intracranial aneurysms.

METHODS

We report the case of a 15-year-old female patient who presented with a World Federation of Neurosurgical Societies grade 5 subarachnoid hemorrhage from an aneurysm at the junction of a persistent primitive hypoglossal artery and the posterior inferior cerebellar artery origin. Supratentorially, unfortunately, there was no parenchymal blush or cortical venous return. Eventually, a multidisciplinary decision was made to withdraw care.

RESULTS

Fifty-seven cases were reported in the literature to date of persistent hypoglossal arteries, 16 of which presented with an associated aneurysm, 5 with an arteriovenous malformation, and 6 with a subarachnoid hemorrhage. Our case is the youngest patient reported so far. Hypoplasia or aplasia of the vertebral artery often were encountered (36 and 13 cases, respectively), as well as carotid artery stenosis (15 cases).

CONCLUSIONS

Although uncommon, it is important to recognize persistent carotid-basilar connections, since they have a considerable hemodynamic impact on the posterior cerebral circulation via the carotid system. A critical reduction in the carotid blood flow will, therefore, have ischemic consequences in the posterior cerebral territories. In addition, such connections might be associated with anomalies of the vessel wall and be predisposed to aneurysm formation. The endovascular neurointerventionalist, as well as the vascular and skull base neurosurgeon, need to be aware of their anatomy and variations.

Unilateral Aplasia versus Bilateral Aplasia of the Vertebral Artery: A Review of Associated Abnormalities

Morphological characteristics of 108 cases of uni- and bilateral aplasia of the vertebral artery (VA) in reports or images of retrospective studies, including one recent case, published between 1967 and 2016 are analyzed. Incidence, gender, persistence of carotid-vertebrobasilar anastomosis (CVBA), associated with other vascular variants, and vascular pathology in each group of uni- and bilateral VA aplasia are mutually compared. Most of the cases of VA aplasia in ages 31 to 80 were discovered in USA, Japan, and India. The bilateral VA aplasia is more common in the male gender than in the female one. The side of the VA aplasia had a significant effect on the side of CVBA persistence. Associated aplasia of other arteries was more common in cases of unilateral VA aplasia. The left VA was more commonly hypoplastic in cases of single right VA aplasia than the right VA in cases of single left VA aplasia. Aneurysms of definitive arteries were more frequent in cases of single right VA aplasia than in cases of single left VA aplasia. We claim that the aplasia of the VA probably depends on genetic factors in some races, while diseases are expressed usually in persons over 30 years of age.