Proatlantal Artery Research Articles

Bilateral Persistent Primitive Trigeminal Arteries Associated with Trigeminal Neuralgia

Persistent carotid-vertebrobasilar anastomoses (PCVBA) include the primitive trigeminal artery (PTA), the primitive otic artery (POA), the primitive hypoglossal artery and proatlantal arteries (ProAs). The PTA is the most commonly seen of these accounting for approximately 80-85% of PCVBAs. The PTA which connects the internal carotid artery (ICA) to the basilar artery (BA) may occasionally connect to the superior or posterior inferior cerebellar arteries without interposition to the BA. It is then referred to as a persistent trigeminal artery variant (PTAV), an anomalous carotid-cerebellar anastomosis. Bilateral occurrence of PTA is extremely rare. During vertebral artery (VA) development the anterior radicular artery of segment C1 from the proatlantal artery of Padget evolves into the intradural component of the VA (V4 segment) plus a short extradural segment (distal V3 segment). Agenesis of a single anterior radicular artery of ProA results in the absence of one distal VA associated with an unremarkable contralateral VA and the BA. Absence or hypoplasia of the terminal portion of one VA is a commonly observed anatomic variant. However, absence of the terminal portions of both VAs is exceptional. A rare case of bilateral PTAs is presented with unilateral PTA and a contralateral PTAV causing trigeminal neuralgia. Furthermore, the bilateral PTAs were associated with the absence of the proximal portion of the BA in addition to the bilateral lack of a distal VA. This finding comes as a logical consequence of the developmental anatomy of the vertebrobasilar junction and is consistent with the assumed congenital nature of the anatomic variant.

Persistent primitive first cervical intersegmental artery (proatlantal artery II) associated with subarachnoid hemorrhage of unknown origin

Proatlantal intersegmental artery is a persistent arotid–vertebral embryonic anastomosis. This artery is very are, and 2 types have been described, proatlantal artery types and II. Persistent primitive proatlantal intersegmental artery proatlantal artery type I) arises from the internal carotid artery nd transverses rostrally to enter the foramen magnum where t joins the vertebral artery. Persistent primitive first cervical ntersegmental artery (proatlantal artery type II) arises from the xternal carotid artery, runs posteriorly to join the vertebral rtery and then passes through the transverse foramen of the C1 ertebra segment. The purpose of this paper is to present a case ith proatlantal artery type II without an ipsilateral vertebral rtery. This anomaly was an incidental finding in a patient with ubarachnoid hemorrhage (SAH) of unknown origin.

Congenital external carotid–internal carotid artery anastomosis associated with contralateral non-bifurcating cervical carotid artery

Dear Sir, Non-bifurcating cervical carotid artery is a rare anatomical variation of the carotid artery in which the branches of the external carotid artery (ECA) directly arise from the common carotid artery without forming a bifurcation [1, 2]. In addition, cases of congenital EC–internal carotid artery (ICA) anastomosis at the cervical segment forming a large arterial ring have been reported, and it seems to be a variant of the non-bifurcating cervical carotid artery [3]. We wish to bring to your attention a patient showing not only a non-bifurcating cervical carotid artery on one side but also EC–IC anastomosis on the contralateral side. This case suggests that there is a relationship between a nonbifurcating cervical carotid artery and ring formation of the cervical carotid artery. A 71-year-old man underwent CT angiography (CTA) of the extracranial neck vessels, because anomalies of bilateral cervical carotid arteries were discovered at a medical checkup. CTA showed that the right distal common carotid artery changed in caliber at the level of the C6 vertebral body. The major branches of the proximal ECA arose separately from the terminal segment of the common carotid artery or proximal ICA without a proximal main trunk of the ECA (Fig. 1). Thereafter, the artery continued as a normal ICA in the cranial portion. The left carotid bifurcation was located at the level of the C6 vertebral body. The ICA and ECA anastomosed at midcervical level to form a large arterial ring at the proximal cervical segment (Fig. 1). Morimoto et al. [2] first used the term "non-bifurcating cervical carotid artery" as variations/anomalies at the cervical carotid artery in 1990. A non-bifurcating cervical carotid artery is rare, and the overall incidence of the anomaly detected by magnetic resonance angiography was 0.21% [4]. Two hypotheses have been proposed for the development of a non-bifurcating carotid artery [5–7]. The first is agenesis of the common stem of the ECA with regression failure of the hyoid artery. The second is segmental agenesis of the ICA. Embryologically, the cervical carotid arteries develop by complicated processes of regression, and the communication within the vascular network consists of the ventral aorta, dorsal aorta, aortic arches, and intersegmental arteries. The ventral aorta and dorsal aorta communicate via aortic arches. Among them, the first aortic arch (mandibular artery) further regresses, while the second aortic arch (hyoid artery) continues to the stapedial artery. It is generally thought that the ECA develops from both the ventral pharyngeal artery system and the hyoid artery system. According to Lasjaunias et al. [8], the occipital artery (OA) is formed from the proatlantal artery and arises from the primitive ICA, ECA, and vertebral artery at points determined by the sites of regression. In our case, the OAs arose from the right IC and left EC, respectively. When the K. Nakai (*) : T. Kaji : T. Kawauchi :C. Tamura Department of Radiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan e-mail: nakai@ndmc.ac.jp

Type II proatlantal artery (occipital subtype) with bilateral absence of the vertebral arteries

Type II proatlantal artery (occipital subtype) with bilateral absence of the vertebral arteries

Internal carotid and ipsilateral type II proatlantal artery stenoses causing simultaneous hemispheric and vertebrobasilar transient ischemia

A case of persistent proatlantal artery (PA) is described in a 60-year-old woman who presented with cerebellar ataxia, homonymous hemianopia, and aphasia. Both Doppler scan and magnetic resonance angiography (MRA) showed agenesis of both vertebral arteries, 80% stenosis of the left internal carotid artery (ICA), and an anastomotic vessel between the left external carotid artery (ECA) and the left vertebral artery (LVA) with a tight stenosis at the origin. It was thought to be a type II PA. Both lesions were successfully treated by ICA endarterectomy and common carotid artery to PA bypass. This case demonstrates the clinical significance of persistent PA in the evolution of an ischemic cerebrovascular disease.

A case of a type II proatlantal artery with arteriovenous malformation

We describe a 64-year-old woman evaluated with angiography a case of persistence of a proatlantal artery (type II) with an arteriovenous malformation associated to the posterior cerebral artery. This association has been reported once in the literature consulted. The proatlantal artery arises from external carotid artery, cranial to the origin of facial artery at the level of C4 vertebra, anteromedial to the internal carotid artery, laying on it during its course cranial, lateral and posterior. After making a loop at the level of the transverse process of C3 vertebra, it enters into the transverse foramen of C3 vertebra and continuing its course, through the transverse foramen of C2 and C1 vertebra, as vertebral artery. Winds behind the superior articular process of the atlas enters the skull through the foramen magnum and, at the lower border of the pons, joins with the vessel of the opposite side to form the basilar artery. The internal carotid artery is normal. This variation is associated with congenital arteriovenous malformations that represent the persistence of an embryonic pattern of congenital vessels.

Brainstem disconnection associated with nodular heterotopia and proatlantal arteries

We report on a patient with brainstem disconnection associated with periventricular nodular heterotopia and bilateral proatlantal intersegmental arteries. The patient was a girl born after 37 weeks of gestation with birth weight of 1,938 g. Polyhydroamnios and lack of swallowing movement were noted on fetal ultrasonography. No spontaneous body movement or respiration was observed after birth, whereas facial movement was preserved. She had marked generalized weakness and absent deep tendon reflexes. She remains alive and hospitalized at 4 years of age but requires mechanical ventilation and feeding through a gastrostomy tube. MRI showed absence of the lower pons and the medulla oblongata associated with hypoplasia of the cerebellar vermis and hemispheres. In addition, ventriculomegaly and periventricular nodular heterotopia were observed in the cerebrum. MR angiography demonstrated the absence of vertebral arteries and presence of bilateral proatlantal intersegmental arteries arising from the external carotid arteries. Array-comparative genomic hybridization analysis did not show any genomic copy number aberrations. No mutation was found in the FLNA gene or the EN2 gene. The constellation of the malformations of our patient suggested that genes related to the development of the central nervous and vascular system may be involved in the pathogenesis of brainstem disconnection.

Major and Minor Arterial Malformations in Patients With Cutaneous Vascular Abnormalities

The association of persistent embryonic arteries and the absence of 1 carotid or vertebral arteries with facial or neck hemangioma or vascular malformation have been frequently described. The abnormalities can involve major or minor vessels. Of 22 patients of our series with this neurocutaneous syndrome, 20 had the origin of both anterior cerebral arteries from the same internal carotid artery. Thirteen patients showed absence or hypoplasia of 1 carotid artery and 10 of 1 vertebral artery; 10 showed persistence of the trigeminal artery; 3 had persistent proatlantal artery; 6 showed the absence of the posterior communicating artery; and 4 had hypoplastic posterior cerebral artery. Other less frequent abnormalities were found in 7 patients. Intellectual level of most patients was either borderline or below normal. Abnormalities in the vascularization and perfusion of the frontal lobes may contribute to the borderline or lower mental level of these patients.

Congenital and Evolving Vascular Disorders Associated with Cutaneous Hemangiomas: Case Report

Conventional arteriography in an 11-month-old boy with cardiopathy, aortic arch coarctation and haemangiomas showed the absence of the right internal carotid and vertebral arteries, hypertrophy of the right external carotid artery, with enlargement of the internal maxillary and ophthalmic arteries that supplied the right cerebral hemisphere. An MRI study showed an infarcted area in the posterior zone of the left cerebral hemisphere vascularised by the middle cerebral artery that was caused by a thrombosis during a severe bout of gastroenteritis. MRA studies performed at 16 and 23 years of age revealed progressive narrowing of the left carotid and vertebral arteries, persistence of the proatlantal and trigeminal arteries, and poor cerebral vascularisation that, at adult age, was entirely supplied through collateral arteries, branches of both external carotids, the presence of unilateral duplication of the vertebral arteries and ascending pharyngeal artery.

The right vertebral artery arising as a branch of the right internal carotid artery: report of a rare case

Atypical origins of the vertebral artery (VA) are rare anatomical findings. We present an extremely rare arrangement of the cerebral circulation in a 61-year-old male patient detected on magnetic resonance angiography, where the right VA arose as a direct branch of the cervical internal carotid artery (ICA). This likely reflects the failure of the pro-atlantal artery to regress during the third to fourth week of embryological life. Although the effect of the variant on symptomology is debateable, knowledge of the potential for the VA to arise as a branch of the ICA is pertinent to radiologists and surgeons operating on the great vessels and their branches, particularly vascular surgeons undertaking carotid endarterectomy.

Bilateral Segmental Agenesis of the Vertebrobasilar Junction: Developmental and Angiographic Anatomy

Bilateral vertebrobasilar junction agenesis is an exceptional anatomic variation. This article explores the angiographic characteristics of this variant and its embryologic mechanisms. Two observations of bilateral agenesis of the vertebrobasilar junction are reported. A case of atheromatous disease of the vertebrobasilar junction is shown to highlight characteristics distinguishing such a lesion from the reported variant. In the 2 reported cases, the distal segment of both vertebral arteries (VAs) and the proximal portion of the basilar artery (BA) were absent. In addition, distal connections of the BA with the posterior cerebral arteries (PCA) were also lacking. As a consequence, the remaining portion of the BA was isolated from its usual sources of blood supply, which was provided by a persistent carotid-basilar anastomosis. The developmental mechanism underlying bilateral agenesis of the vertebrobasilar junction likely involves the anterior radicular artery of C1. This branch of the proatlantal artery normally becomes the adult distal VA and the proximal BA. The lack of cranial connection of the BA with the PCA may be secondary to the proximal vertebrobasilar agenesis and the resulting paucity of antegrade flow within the BA. Alternatively, the absence of both the proximal and distal connections of the BA could be the result of a similar, yet unknown, developmental mechanism. From a clinical standpoint, this vascular anomaly was discovered incidentally in our 2 patients, a finding consistent with the assumed congenital nature of the variant.

Facial Hemangioma and Hemispheric Migration Disorder: Presentation of 5 Patients

The association of cortical organization disorders with facial hemangiomas or vascular malformations has been described in only a few reports. The purpose of this study was to show the close association of these cutaneous anomalies with cortical dysplasias and intracranial vascular abnormalities. Five patients, all women, with cutaneous vascular abnormalities, 4 with hemangioma and 1 with vascular malformation, were studied with MR and MR angiography. All 5 of the patients showed cortical dysplasia. The cutaneous lesions involved the left frontal region, ipsilateral to the cerebral hemisphere with cortical dysplasia, in all of the patients. Four patients had seizures that responded well to antiepileptic drugs. Hemispheric hypoplasia was associated with the cortical dysplasia in all 5 of the patients. Arterial abnormalities were found in all of the patients, consisting of aplasia of the ipsilateral internal carotid artery in 2, persistence of the trigeminal artery in 2, persistence of both proatlantal arteries and double kinking in the internal carotid artery in 1, and origin of both anterior cerebral arteries from the same internal carotid in all 5 of the patients, 1 of whom also showed an intracavernous anterior cerebral artery origin of the same side of the hemispheric hypoplasia and polymicrogyria. Seizures and mild psychomotor delay could be caused by the cortical dysplasia and the hemispheric hypoplasia. The presence of many congenital vascular abnormalities in this series suggests that facial hemangioma and vascular malformations may be in close relationship with cortical and vascular abnormalities. The reason that the vascular and cortical abnormalities occurred in the left side in all 5 of the patients and the mechanism underlying the association of both malformations are unclear. A genetic origin is suggested.

Cutaneous Hemangioma Associated With Persistence of the Trigeminal and Both Proatlantal Arteries

The authors describe a girl who was evaluated at 7 years old because of facial segmental hemangioma associated with unilateral persistent trigeminal artery, bilateral proatlantal arteries, hypoplasia of 1 posterior cerebral artery, kinking of 1 internal carotid artery at 2 different levels, and transdural collateral vascularization supplying the posterior areas of the cerebral hemispheres. This is the first patient known to have a cutaneous hemangioma associated with bilateral proatlantal arteries despite having a unilateral facial hemangioma.

Surgical revascularization in the presence of a preserved primitive carotid-basilar communication

Anomalous arteries that connect the anterior and posterior cranial arterial systems are unusual variants that can severely alter normal patterns of cerebral blood flow. Persistent trigeminal, hypoglossal, otic, and proatlantal arteries have been described. This report illustrates the technical aspects of carotid endarterectomy with an ipsilateral preserved primitive carotid-basilar communication. Identification of the internal carotid and hypoglossal arteries, maintenance of cerebral perfusion, arteriotomy closure, preoperative imaging, the use of shunts, and reconstruction strategy are discussed. Preoperative angiography and detailed, individualized surgical strategy should be used to ensure a successful endarterectomy in patients with preserved primitive carotid-basilar communications.

Persistent carotid-vertebrobasilar anastomoses: How and why differentiating them?

The persistent carotid-vertebrobasilar anastomoses (PCVBA) can be explained by an interruption of the vertebrobasilar system (VBS) embryogenesis. We present two very rare cases of persistent anastomoses: a hypoglossal artery and a type I proatlantal artery, insisting on the angiographic criteria allowing differentiation. After a brief review of the embryogenesis of the VBS, we describe the different types of persistent anastomoses (hypoglossal, type I and II proatlantal, trigeminal and otic arteries). We will insist on the potential risks, not well-known, but typical of each anastomosis. PCVBA usually are incidental findings but imaging follow-up may be required since aneurysms may develop.

Persistent hypoglossal artery

It is well known that the internal carotid artery has no branches in the neck during postfetal life (von Lanz & Wachsmuth, 1955), but during embryonic development there are anastomotic connections between the internal carotid and basilar artery that rarely persist after intrauterine life (Hassen‐Khodja et al. 1992; Widmann & Sumpio, 1992; De Caro et al. 1995). The most common anomaly found incidentally on angiography is a persisting trigeminal artery, but persistent hypoglossal, otic and proatlantal arteries can also be found (Reynolds et al. 1980; Ouriel et al. 1988; Salas et al. 1998). We report a rare example of a persistent hypoglossal artery in a 64 y old female cadaver, cause of death unknown, embalmed by standard mortuary procedures for dissection during the routine anatomy course. The persistent hypoglossal artery originated from the anteromedial wall of the left internal carotid artery 2.5 cm above the bifurcation (Fig.). It extended towards the hypoglossal canal. The diameter of its lumen was 1.5 mm. During its course in the neck, it was positioned anterior to the internal carotid artery and medial to the facial and lingual arteries, the posterior belly of the digastric muscle and the convexity of the hypoglossal nerve in the neck. At 1 cm above the convexity of the hypoglossal nerve in the neck, the artery gave rise to a branch that entered the skull through the carotid canal anteromedial to the internal carotid artery (Fig. 1) and joined the basilar artery. The medial branch of the hypoglossal artery crossed the internal carotid artery on its medial side and entered the skull together with the hypoglossal nerve and joined the basilar artery. We found no other anomalies in the cerebral arterial system.

PERSISTENCE OF BOTH PROATLANTAL ARTERIES WITH OCCLUSION OF THE INTERNAL CAROTID ARTERIES

A case of bilateral persistence of the proatlantal arteries with occlusion of both internal carotid arteries is reported.

Persistent primitive proatlantal intersegmental artery (proatlantal artery I) results in 'top of the basilar' syndrome.

Persistent primitive proatlantal intersegmental artery (proatlantal artery I) is an anastomotic channel between the carotid and vertebrobasilar arterial systems. Persistence of this embryonic anastomosis is very rare. The "top of the basilar" syndrome is usually due to occlusion of thalamoperforating arteries by emboli that rise from the vertebrobasilar arterial system. In this case, however, the emboli stemmed from atherosclerotic plaques in the carotid system. A 55-year-old woman was hospitalized with top of the basilar syndrome. A brain scan showed hypodense lesions extending from the mesencephalon to both thalami. Digital subtraction angiography of the cerebral circulation was performed, which revealed a proatlantal artery I on the left side. In addition, atheromatous plaques were seen along the internal and common carotid arteries on the same side. The occurrence of proatlantal artery I is extremely rare. Top of the basilar syndrome is also rarely encountered. To our knowledge, this is the first report of a patient with both conditions.

Right proatlantal artery type I, right internal carotid occlusion, and left internal carotid stenosis: Case report and review of the literature

A 66-year-old man presented with right cerebellar infarction and ischemic lesions in the left dorsal thalamus and right upper parietal lobe. Angiography showed occlusion of the right internal carotid artery proximal to an ipsilateral proatlantal artery type I, 70% stenosis of the left internal carotid artery, and aplasia of both posterior communicating arteries. The carotid occlusion was successfully treated by thrombendarterectomy. Persistence of a proatlantal artery is a rare condition. In relation to the 38 literature reports on proatlantal arteries, this case demonstrates the clinical significance of a persistent proatlantal artery in the evolution of atypical ischemic cerebrovascular disease.

Ｐｅｒｓｉｓｔｅｎｔ ｃａｒｏｔｉｄ‐ｖｅｒｔｅｂｒａｌ ａｎａｓｔｏｍｏｓｉｓの１例

A case of persistent carotid-vertebral anastomosis with occlusion of the right internal carotid artery is reported. This 68-year-old man was admitted to our hospital with left hemiparesis. Physical examination findings on admission were within normal range except for the hemiparesis and his blood pressure was 114 over 70mmHg. Right carotid angiogram revealed an occlusion of the right internal carotid artery and an abnormal vessel connecting the right external carotid artery and right vertebral artery. The vertebral arteries were hypoplastic bilaterally. Thereafter, the patient was transferred to the rehabilitation center and spent 134 days in the hospital. This “abnormal vessel” arises from the right occipital artery which branches from the right external carotid artery at the level between the 2nd and the 3rd vertebrae. It then curves slightly superiorly and joins the third portion of the right vertebral artery. This anastomotic vessel was thought to be “proatlantal artery II” in accordance with Lasjaunias et al. or a “persistent primitive first cervical intersegmental artery” in accordance with Padget. To our knowledge, this is only the 19th case of persistent carotid-vertebral anastomosis reported in the literature.