Monolateral type I proatlantal artery with bilateral absence of vertebral arteries: description of a case and review of the literature

Embryology of the vertebral artery and variants of the adult

The vertebral arteries represent in the adult the main blood supply of the posterior cranial fossa, even if they appear relatively late during the embryological life. We reviewed all the most important steps of the vertebral artery's embryological development and the most common variants that can occur in the adult. The aim of this review is to summarize the main events of the development of this artery and to give an embryological explication for the most common variants of this artery.

Case Report: Stent Retriever Thrombectomy of Acute Basilar Artery Occlusion via the Type 1 Proatlantal Intersegmental Artery

Stent retriever thrombectomy (SRT) is one of the most effective methods for the recanalization of acute basilar artery occlusion (ABAO). The proatlantal intersegmental artery (PIA) is a rare carotid-vertebrobasilar anastomosis. Recognition of this rare form of anastomosis is particularly important for the rapid establishment of positive blood flow in patients with ABAO. In this case, the patient had a rare, left type 1 PIA. The right vertebral artery (VA) was tenuous and did not enter the cranium. We performed a thrombectomy of the ABAO by inserting a catheter via the type 1 PIA. The complete recanalization of basilar artery (BA) flow was achieved following two stent retractions; however, the patient eventually died of brain stem hemorrhage.

Aberrant course of the petrous internal carotid artery associated with ipsilateral type 1 proatlantal artery

PURPOSE

To describe an extremely rare case of an aberrant course of the petrous internal carotid artery (ICA) associated with an ipsilateral type 1 proatlantal artery (PA) that was diagnosed by cerebral magnetic resonance (MR) angiography.

CASE REPORT

The patient was a 64-year-old man with double vision. Cerebral MR imaging and MR angiography were subsequently performed using a 1.5-T scanner. MR angiography showed an aberrant course of the petrous right ICA that was associated with right type 1 PA. The left vertebral artery (VA) and proximal right VA were absent.

DISCUSSION

An aberrant course of the petrous ICA is rare but clinically significant, because it is dangerous during middle ear surgery. Type 1 PA is an extremely rare type of persistent fetal anastomosis between the carotid and vertebrobasilar systems. Type 1 PA is also clinically significant, because it is dangerous during craniovertebral junction surgery. We found no similar cases in the relevant English-language literature.

CONCLUSION

Although both variations were seen ipsilaterally and were located relatively close to each other, the embryological development of these variations is quite different. In addition, no similar case has been reported previously. Thus, these may have formed incidentally.

A Type 1 Persistent Proatlantal Artery Originating from the External Carotid Artery Detected by Computed Tomographic Angiography

A persistent proatlantal artery (PA) is rare. We report a type 1 persistent PA originating from the right external carotid artery (ECA). A 78-year-old woman presented with dizziness. Computed tomographic (CT) angiography showed a persistent PA originating from the right ECA. This persistent PA did not pass through the atlas transverse foramen. The extracranial segment of this artery in the atlas transverse process level had a more lateral position than a normal left vertebral artery. CT angiography well demonstrated the relationship with bony structures and the course of this persistent PA. This anomalous artery in our patient presented as an incidental finding. Surgeon should recognize a persistent PA when performing carotid endarterectomy or ligation of the ECA for avoidance of complication.

Congenital absence of the bilateral internal carotid artery: a review of the associated (ab)normalities from a newborn status to the eighth decade of life

PURPOSE

Due to the fact that the internal carotid artery (ICA) is responsible for nourishing two thirds of the brain volume, our aim was to inspect the morphofunctional consequences of the bilateral lack of this artery.

METHODS

In order to examine this condition, we referred to both the library archive of our Faculty of Medicine and electronic databases of anatomical and clinical reports that included the following keywords: "absence," "aplasia," or "agenesis" in combination with "internal carotid artery," "common carotid artery," or only "carotid artery."

RESULT

We found 60 recorded cases of the bilateral ICA absence in the subjects of newborn status to the eighth decade of life, which had been discovered in 20 countries. The following ten parameters were described: the embryological base, terminology, history, incidence, general data, differential diagnosis, collateral circulation, the associated vascular aplasia and/or other variants, pathophysiology, and the importance in praxis.

CONCLUSION

This review noted all the cases of the bilateral ICA aplasia published for the past 104 years. Although there were 11.6% of cases of the associated cerebral aneurysms and 1-4 cases of 16 other diseases, approximately one quarter of the cases was without any pathology.

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.

A Previously Unreported Arterial Variant of the Suboccipital Region Based on Cadaveric Dissection

Introduction Several arterial variants have been reported to occur around the posterior arch of the atlas. Understanding the various anomalies and diagnosing them preoperatively can dramatically reduce the risk of surgical insult during neurosurgical procedures. Herein we report a case of an arterial variant found just below the posterior arch of C1. Case Report During the routine dissection of the suboccipital region via a posterior approach, an unusual bulge was identified just inferior to the inferior capitis oblique muscle. With further dissection, the structure was identified as a tortuous internal carotid artery. Conclusion Arterial variants around the posterior arch of C1 are surgically significant and can result in catastrophic injuries if unappreciated. Most of these variants will be related to the vertebral artery. To our knowledge, an arterial variant of the internal carotid artery in this location, as reported herein, has not been previously reported.

Arterial variations around the atlas: a comprehensive review for avoiding neurosurgical complications

INTRODUCTION

Neurosurgical approaches often involve the atlas. Therefore, the arterial relationships and anatomical variations are of paramount importance to the neurosurgeon.

METHODS

Using standard search engines, a literature review of arterial variants near the first cervical vertebra was performed.

CONCLUSIONS

Arterial variations around the atlas are surgically significant. Awareness of their existence and course may provide better pre-operative planning and surgical intervention, potentially leading to better clinical outcomes. Three-dimensional computed tomography angiography (3D CTA) is an important tool for identifying and diagnosing such abnormalities and should be used when such vascular anomalies are suspected.

Left type I proatlantal artery with bilateral aberrant vertebral arteries and a ruptured aneurysm: a case report and review of the literature

Persistent proatlantal artery is one rare kind of persistent primitive anastomoses between carotid and basilar vascular system. This case firstly introduces a type I proatlantal artery with complex vascular anomalies of bilateral vertebral arteries and a ruptured aneurysm, which is extremely uncommon. A 43-year-old female was hospitalised for SAH and ventricular hematocele. The subsequent digital subtraction angiography and computed tomography angiography revealed a type I proatlantal artery which arises from left internal carotid artery, associating with a hypoplastic right vertebral artery, an aplastic left vertebral artery and a ruptured left posterior inferior cerebellar artery aneurysm. An interventional procedure was taken later. The present case raises awareness on the incidence of persistent primitive anastomoses which combined other complex vascular anomalies before surgical or interventional procedures, especially in view of unique blood supply to posterior circulation from the primitive vessel.