A systematic classification of the vertebral artery variable origin: clinical and surgical implications

Abstract

Several congenital anomalies regarding the right (RVA) and left (LVA) vertebral artery have been described. The current paper aims to perform a systematic literature review of the variable vertebral artery (VA) origin from the aortic arch (AOA) and its branches. The incidence of these variants and the ensuing AOA branching pattern are highlighted. Atypical origin cases were found more commonly unilaterally, while LVA presented the majority of the aberrancies. The LVA emersion from the AOA (3.6%) and the RVA from the right common carotid artery (RCCA) (0.14%) were the commonest origin variations. Aberrant RVA origin as last branch of the AOA is very rare. Eighteen cases (0.12%) with an aberrant right subclavian artery (ARSCA) were found. Among them, the RVA originated from the RCCA and right subclavian artery in 94.4 and 5.6%, respectively. Sporadic cases had an AOA origin bilaterally; RVA and LVA had a double origin in 0.027 and 0.11%, respectively. A dual origin was detected in 0.0069%, bilaterally. The atypical VA origin may coexist with: (i) an ARSCA, (ii) a common origin of brachiocephalic artery and left common carotid artery (the misnomer bovine arch) and (iii) a bicarotid trunk. The aberrant VA origin favors hemodynamic alterations, predisposing to cerebrovascular disorders and intracranial aneurysm formation. Detailed information of VA variants is crucial for both endovascular interventionists and diagnostic radiologists involved in the treatment of patients with cerebrovascular disease. Such information may prove useful to minimize the risk of VA injury in several procedures.

Two cases of dual origin left vertebral arteries with non-convergence

“…Finding two dual origin vertebral arteries in a sample of 38 individuals suggests a much higher frequency (approximately 5% of the total population) than has been previously reported [3,11] and would increase the number of reported cases by roughly 4%. This suggests the frequency of dual origin vertebral arteries is underreported.…”

“…I n typical human anatomy, the vertebral arteries (VA) originate from the subclavian arteries (SCA), enter the transverse foramen of the sixth cervical vertebra (C6), and travel within the subsequent more superior transverse foramina to enter the skull via the foramen magnum, and provide circulation to the posterior brain. Reported frequencies of VAs with aberrant origins vary widely, and have been reported in anywhere from 5 to 50% of the population [1][2][3]. Of those, left vertebral artery (LVA) variants are most common, appearing in approximately 2 to 7% of the population (as reported in a recent aggregation of studies) [1].…”

“…Of those, left vertebral artery (LVA) variants are most common, appearing in approximately 2 to 7% of the population (as reported in a recent aggregation of studies) [1]. Approximately 90% of those are part of an atypical aortic arch (AA) branching pattern [3]. The clinical significance of a more medial location of these aberrant LVAs [1,[3][4][5][6], in conjunction with their oft-observed more superior entry into the C4 transverse foramen (rather than C6) [7] result in a need to understand their frequency in the population, as well as any co-existing vascular variations.…”

“…Dual origin VAs present additional clinical concerns, as they have been previously misdiagnosed as a dissection or fenestration of the VA [5]. They have also been reported to be indicators of increased risk of dissection, and have anecdotally been linked to pain, dizziness, headache, nausea, cognitive impairment, and other pathologies [1,3]. Additionally, many reports of aberrant LVAs document a more superior transverse foramen entry than normal [1,7] but they do not explicitly discuss the presence of arteries in the more inferior foramina (which would indicate a dual origin VA), so this phenomenon may be underreported.…”

Commentary: Dealer's choice!

“…The isolated left vertebral artery (ILVA) has its origin directly off the aorta, and is the second most common (after bovine arch) aortic arch variant, occurring in 2% to 4% of patients. 1,2 In their article in this issue of the Journal, ''Transposition of the Left Vertebral Artery During Endovascular Stent-Graft Repair of the Aortic Arch,'' Piffaretti and colleagues 3 report their experience with transposition of the ILVA during stent-graft repair of the aortic arch and descending thoracic aorta. They achieved successful outcomes without neurologic sequelae in all cases.…”