Extreme fenestration of the right vertebral artery: magnetic resonance angiographic demonstration

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

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.

Duplicated and Hypoplastic V4 Segment of Vertebral Artery along with Duplication of Anterior Inferior Cerebellar Artery: A Case Report

Variations of V3 and V4 segments of Vertebral Artery (VA) are very rare. We report an extremely rare case of hypoplastic and duplicated V4 segment of right VA along with variant origin of right Anterior Inferior Cerebellar artery (AICA) from right Posterior Inferior Cerebellar artery (PICA). AICA was duplicated, with one vessel arising from PICA and another arising from distal Hypoplastic Vertebral Artery (HVA). HVA should be considered for the diagnosis of acute stroke of brainstem and cerebellum. Knowledge about VA variations is important to prevent iatrogenic injuries during surgeries involving posterior cranial fossa.

Developmental anomalies of the distal vertebral artery and posterior inferior cerebellar artery: diagnosis by CT angiography and literature review

PURPOSE

The aim of this study was to identify variations in the anatomy of the distal vertebral artery (VA) and posterior inferior cerebellar artery (PICA) with computed tomography (CT) angiography.

METHODS

CT angiography was performed at two hospitals. And the results were analyzed for VA anomalies.

RESULTS

Seven of the 3067 patients who received brain CT angiography in first hospital had seven intracranial VA fenestrations. Twelve of 546 patients who received CT angiography of intracranial and extracranial vessels in second hospital had 16 anatomical variations of the V3 segment. Two fenestrations of the V3 segment, three C1 origins of the PICA, seven aberrant VAs with an intradural course at the C2 level without a normal VA, and four aberrant VAs with an intradural course at the C2 level with a normal VA were observed. Seventeen of the 314 patients who received cervical CT angiography in second hospital had 21 anatomical variations of the VA. Two fenestrations of the V3 segment, six C1 origins of the PICA, three C2 origins of the PICA, one VA origin of the occipital artery, one fenestration of the V4 segment, five aberrant VAs with an intradural course at the C2 level without a normal VA, and three aberrant VAs with an intradural course at the C2 level with a normal VA were observed.

CONCLUSIONS

A certain number of anatomical variants of the distal VA and PICA may reflect variations in size and connections of the lateral or posterior spinal artery.

Unusual Finding of Vertebral Artery Fenestration in Spontaneous Deep Nuclear Hemorrhage

Vertebral artery fenestration is accidentally detected during angiography or autopsy. Spontaneous deep nuclear hemorrhage in association with vertebral artery fenestration is a very unusual finding in angiography. Such an unusual finding has not been reported in the English literature. Here, we report two cases of spontaneous deep nuclear hemorrhage that presented with features of raised intracranial pressure. Computed tomography revealed a deep nuclear acute bleed in both cases. Digital subtraction angiographic findings were normal other than the presence of a long segment vertebral artery fenestration. Both extracranial and intracranial variations were detected. Although the existence of vascular fenestration in the vertebrobasilar system produces less clinical importance, it may influence the management of cervical and intracranial pathologies to avoid iatrogenic injury. 

Vertebral Artery Injury during Routine Posterior Cervical Exposure: Case Reports and Review of Literature

Study Design Case series. Objective We report the unusual occurrence of vertebral artery injury (VAI) during routine posterior exposure of the cervical spine. The importance of preoperative planning to identify the course of the bilateral vertebral arteries during routine posterior cervical spine surgery is emphasized. Methods VAI is a rare but potentially devastating complication of cervical spinal surgery. Most reports of VAI are related to anterior surgical exposure or screw placement in the posterior cervical spine. VAI incurred during posterior cervical spinal exposure surgery is not adequately addressed in the existing literature. Two cases of VAI that occurred during routine posterior exposure of the cervical spine in the region of C2 are described. Results VAI was incurred unexpectedly in the region of the midportion of the posterior C1-C2 interval during the initial surgical exposure phase of the operation. An aberrant vertebral artery course in the V2 anatomical section in the region between C1 and C2 intervals was identified postoperatively in both patients. A literature review demonstrates a relatively high incidence of vertebral artery anomalies in the upper cervical spine; however, the literature is deficient in reporting vertebral artery injury in this region. Recommendations for preoperative vertebral artery imaging also remain unclear at this time. Conclusions Successful management of this unexpected complication was achieved in both cases. This case report and review of the literature highlights the importance of preoperative vertebral artery imaging and knowledge of the course of the vertebral arteries prior to planned routine posterior exposure of the upper cervical spine. In both cases, aberrancy of the vertebral artery was present and not investigated or detected preoperatively.

Complex aortic arch anomaly: Right aortic arch with aberrant left subclavian artery, fenestrated proximal right and duplicated proximal left vertebral arteries-CT angiography findings and review of the literature

Congenital aortic arch and vertebral artery anomalies are a relatively rare finding discovered on imaging either incidentally or for evaluation of entities like dysphagia or subclavian steal. Right aortic arch is an uncommon anatomical anomaly that occurs in less than 0.1% of the population, and in half of these cases the left subclavian artery is also aberrant.(1) Unilateral vertebral artery (VA) duplication is rare with an observed prevalence of 0.72% in cadavers.(2) Fenestration of the VA is more common than duplication, with a prevalence of approximately 0.23%-1.95%.(3,4) We describe the case of a 25-year-old female who was found to have a right aortic arch with aberrant left subclavian artery, duplicated left vertebral artery and a fenestrated right vertebral artery on CT angiography performed for evaluation of dysphagia. This combination of findings has not been reported before, to the best of our knowledge. We review the embryologic mechanism for the development of the normal aortic arch, right aortic arch, vertebral artery duplication and vertebral artery fenestration. The incidence of these entities, resultant symptoms and clinical implications are also reviewed. The increased associated incidence of aneurysm formation, dissection, arteriovenous malformations and thromboembolic events with fenestration is also discussed.

Vertebral Artery Fenestration

Fenestration of the vertebral artery is a rare vascular anomaly that has been observed at autopsy and on angiography. It is most commonly seen in the extracranial segments of the vertebral artery. This congenital anomaly can arise during multiple different stages of embryological development of the vertebral artery. The clinical significance is unclear, but multiple studies have reported association with other vascular anomalies. Awareness of vascular anomalies is crucial to avoid iatrogenic injuries during endovascular diagnostic and therapeutic interventions. Here, we present a case of a patient with an intracranial vertebral artery fenestration that was identified during work-up for a foramen magnum mass.

Cerebral arterial fenestrations

Arterial fenestrations are an anatomic variant with indeterminate significance. Given the controversy surrounding fenestrations we sought their prevalence within our practice along with their association with other cerebrovascular anomalies. We retrospectively reviewed 10,927 patients undergoing digital subtraction angiography between 1992 and 2011. Dictated reports were searched for the terms "fenestration" or "fenestrated" with images reviewed for relevance, yielding 228 unique cases. A Medline database search from February 1964 to January 2013 generated 304 citations, 127 cases of which were selected for analysis. Cerebral arterial fenestrations were identified in 228 patients (2.1%). At least one aneurysm was noted in 60.5% of patients, with an aneurysm arising from the fenestration in 19.6% of patients. Aneurysmal subarachnoid hemorrhage or non-aneurysmal subarachnoid hemorrhage were present in 60.1% and 15.8%, respectively. For the subset of patients with an aneurysm arising directly from a fenestration relative to those patients with an aneurysm not immediately associated with a fenestration, the prevalence of aneurysmal subarachnoid hemorrhage was 66.7% vs. 58.6% (p = 0.58). Fenestrations were more often within the posterior circulation (73.2%) than the anterior circulation (24.6%), though there was no difference in the prevalence of aneurysms within these groups (61.1% vs. 60.7%, p = 1.0). Cerebral arterial fenestrations are an anatomic variant more often manifesting at the anterior communicating arterial complex and basilar artery and with no definite pathological relationship with aneurysms.

Fenestrated vertebral artery

Fenestrations of the vertebral arteries (VAs) are usually identified angiographically. A left fenestrated vertebral artery (fVA) is reported here, identified in an adult specimen by microdissection. The distal segment of this VA was fenestrated and it consisted of two arms, the caudal one being larger than the cranial one. The caudal end of the rostral arm and the left posterior inferior cerebellar artery (PICA) were inserted at the same point. The anterior spinal artery was leaving the caudal arm of the fVA. On that side the anterior inferior cerebellar artery (AICA) was rudimentary, its cerebellar hemispheric territory being supplied by the PICA. The rostral arm of the fVA and the AICA were united by an anastomosis coursing on the ventral side of the olive. The AICA-to-fVA anastomosis, as well as the PICA, were supplying perforator arteries of the retro-olivary sulcus. Anatomical details of various arterial morphologies are important during specific surgical and interventional procedures.

Fenestration and duplication of the vertebral artery: the anatomical and clinical points of view

The vertebral artery (VA) acts as a foundation for the posterior circulation of the head and neck. It presents a number of anomalies that can be easily visualized thanks to modern imaging techniques, such as MR and CT angiography or color Doppler ulrasonography. Determining the appropriate terminology for those anomalies can be sometimes more challenging than their recognition. One particular challenge concerns the differentiation between VA fenestration and duplication. Because of the different clinical prognoses associated with those anomalies, confusion should be avoided. Knowledge of the morphological anomalies associated with the VA is important for both radiologists and head and neck surgeons, because any injury to the VA can result in a threat to the vascular supply of the brain stem, the cerebral or cerebellar hemispheres, the thalamus, cervical nerve roots and particularly the lateral medulla (Wallenberg's syndrome). This article analyses world literature concerning the issue of VA fenestration and duplication to facilitate a differential diagnosis.

Fenestrations of the intracranial vertebrobasilar system diagnosed by MR angiography

INTRODUCTION

Fenestrations of cerebral arteries are most common in the vertebrobasilar (VB) system, and magnetic resonance (MR) angiographic studies of these variations are sparse.

METHODS

We retrospectively reviewed MR angiographic images of 3,327 patients; images were obtained using two 1.5-T imagers and picked up fenestrations of the intracranial vertebral artery (VA), VB junction, and basilar artery (BA) for evaluation.

RESULTS

In 92 patients, we found 93 fenestrations (2.80%), which included 18 of the intracranial VA (0.54% prevalence), 6 of the VB junction (0.18%), and 69 of the BA (2.07%). Most VA fenestrations were large, and the posterior inferior cerebellar artery arose from the fenestrated segment in 10 patients (56%). Fenestrations of the VB junction were small and triangular. Sixty-five (94%) of the 69 BA fenestrations were located at the proximal segment and had small slit-like configurations. The anterior inferior cerebellar artery arose from the fenestrated segment in 27 patients (37%). We found 18 cerebral aneurysms in 16 (17%) of the 92 patients with fenestration but detected only one aneurysm at the fenestration.

CONCLUSION

The overall prevalence of fenestrations of the intracranial VB system was 2.77%. We found associated cerebral aneurysms relatively frequently but rarely at the fenestration.

Case reports: management of intractable upper extremity pain with continuous subarachnoid block at the low cervical level without impairment of upper extremity function

We present a case of continuous subarachnoid block for the treatment of refractory cancer pain in the shoulder and upper extremity on the right side of the patient. The catheter tip was placed in the subarachnoid space close to the nerve roots on the right side at the height of C5 corresponding to the painful region. Until the patient died, his pain was controlled with infusions of bupivacaine (30-58.7 mg/d) and morphine (2-19.6 mg/d) for 120 days during which upper extremity function was not disturbed and respiratory function and performance status were improved. This case suggests continuous subarachnoid block at the low cervical level is useful for refractory cancer pain in the shoulder and upper extremity.