Entrance and origin of the extracranial vertebral artery found on computed tomography angiography

Left Vertebral Artery Arising Directly From the Arch of the Aorta With a Prevailing Vascular Problem: A Case Report

Aberrant origin of the vertebral artery is a rare case. Due to its important clinical significance during operations in the superior mediastinum and the root of the neck, the variations of this artery should be clarified, and any cadaveric case should be explored specifically if accompanied by any vascular problem. In this cadaveric case, the embalmed male cadaver was found to have a pacemaker wire inserted in the heart through the superior vena cava, denoting a vascular incompetence due to sinus arrhythmia. The left vertebral artery was found to originate from the aortic arch, positioned between the left common carotid artery and the left subclavian artery. It traveled upward behind the left common carotid artery, passing in front of the stellate ganglion and the ventral rami of cervical spinal nerves before entering the left foramen transversarium of the C6 vertebra. This atypical left vertebral artery, which had an unusual origin from the arch of aorta, was distinct from the right vertebral artery, that typically arises from the right subclavian artery. Also, the left atypical artery was found to be narrower and longer than the right one. Additionally, the left common carotid artery exhibited an unusual origin from the beginning of the brachiocephalic trunk. The present case report would be of significance for vascular surgeons in designing surgical intervention in the root of the neck and for clinicians responsible for monitoring patients with variant vertebral arteries to effectively manage potential vascular complications.

Basilar Artery Occlusion Caused by Extracranial Vertebral Artery Dissection on Its Entry into the Transverse Foramen of the C6 Vertebra: Case Report

Objective

Basilar artery occlusion (BAO) is an infrequent form of acute life-threatening stroke and may occur secondary to vertebral artery dissection (VAD). VAD, which occurs spontaneously and sometimes results from mechanical stress or blunt force trauma to the neck, sometimes occurs in the V1-V2 junction, but there are not many reported cases of those. Herein, we report a pictorially illustrative and clinically informative case of VAD in the V1-V2 junction following BAO.

Case Presentation

The patient was a 27-year-old woman who was transferred to our hospital with abrupt severe unconsciousness. On admission, she presented with generalized convulsions and respiratory arrest, and pan-scan CT and CTA indicated BAO. We performed mechanical thrombectomy and achieved recanalization of the basilar artery, and she was diagnosed with BAO secondary to the right VAD at the entry of the C6 transverse foramen (V1-V2 junction). In hindsight, she had scapula and back pain before the onset. She recovered with a modified Rankin scale score of 3 after 90 days from the onset.

Conclusion

VAD sometimes occurs at its entry into the transverse foramen of the C6 vertebra. In this case, VAD may be affected by minor trauma and potentially histological fragility due to the embryonic development process. Although BAO is sometimes difficult to diagnose because it presents with various symptoms, BAO secondary to VAD should be considered in cases of abrupt severe unconsciousness preceded by neck, scapula, or back pain in young and healthy persons.

Mapping of Anatomic Variants of the Proximal Vertebral Artery in Relation to Embryology

BACKGROUND AND PURPOSE

Variations in the origins and courses of the vertebral arteries are relatively rare but may be clinically meaningful. We hypothesize a relationship between variant origins of the vertebral arteries and their levels of entry to the foramina transversaria.

MATERIALS AND METHODS

In this retrospective study of CT angiograms, we document the frequency and types of vertebral artery variants, correlating origins with levels of entry to the foramina transversaria.

RESULTS

Vertebral artery variants were observed in 18.7% of a sample of 460 CT angiograms of the neck. Right-sided variants were less common than left (44.2% versus 68.6%, with 12.8% bilateral) and more common than previously thought. The most common variant on both sides was a variant origin proximal to the normal vertebral artery origin and entry at C5. Most right vertebral arteries originating within 2 cm of the origin of the right subclavian artery and left vertebral arteries originating between the left common carotid and subclavian arteries were "high-entry" variants. Most "low-entry" variants, entering at C7, took origin from the arch just distal to the left subclavian artery or at a common origin with the costocervical trunk. Multiple origins or accessory vertebral arteries were also described, and each moiety followed the same rules described for single origins. A map of vertebral artery origins mirrored the map of aortic arch embryology.

CONCLUSIONS

Vertebral artery variants follow certain well-defined patterns that correlate with the embryology of the aortic arch and great vessels.

The Vertebral Artery: A Systematic Review and a Meta-Analysis of the Current Literature

(1) Background. The anatomical variations of the vertebral arteries (VAs) have a significant impact both in neurosurgery and forensic pathology. The purpose of this study was to evaluate the variational anatomy of the vertebral artery. We evaluated anatomical aspects regarding the V1 and V2 segments of the VA: origin, course, tortuosity, hypoplasia, and dominance, and established the prevalence of each variation. (2) Methods. We conducted a systematic search in PubMed and Google Scholar databases, up to December 2022. Sixty-two studies, comprising 32,153 vessels, were included in the current meta-analysis. We used a random-effects model with a DerSimonian-Laird estimator. The confidence intervals were set at 95%. The heterogeneity between studies was assessed using I². The funnel plot and Egger's regression test for plot asymmetry were used for the evaluation of publication bias. Statistical significance was considered at p < 0.05. (3) Results. The most common site for the origin of both VAs was the subclavian artery. The aortic arch origin of the left VA had a prevalence of 4.81%. Other origins of the right VAs were noted: aortic arch (0.1%), right common carotid artery (0.1%), and brachiocephalic trunk (0.5%). Ninety-two percent of the VAs entered the transverse foramen (TF) of the C6 vertebra, followed by C5, C7, C4, and least frequently, C3 (0.1%). Roughly one out of four (25.9%) VAs presented a sort of tortuosity, the transversal one representing the most common variant. Hypoplasia occurred in 7.94% of the vessels. Left VA dominance (36.1%) is more common, compared to right VA dominance (25.3%). (4) Conclusions. The anatomy of the VA is highly irregular, and eventual intraoperative complications may be life-threatening. The prevalence of VA origin from the subclavian artery is 94.1%, 92.0% of the VAs entered the TF at C6, 26.6% were tortuous, and 7.94% were hypoplastic.