Anatomical features and clinical relevance of a persistent trigeminal artery

Incidental Finding of Persistent Trigeminal Artery in a Young Woman: A Case Report

Persistent trigeminal artery disease is one of the most common types of persistent carotid-vertebrobasilar anastomoses. Usually, it is unilateral, and it can be discovered with a magnetic resonance angiography (MRA), computed tomography angiography (angioCT), or classic angiography exam. It can be associated with non-specific symptoms, such as headaches, or more specific ones, such as III or VI nerve palsy or trigeminal neuralgia, but most of the time it goes undetected, being an incidental finding and not causing any symptoms. On MRA and angioCT, it has the characteristic "tau" sign. We present the case of a young woman who, incidentally, discovered this malformation after undergoing an MRA. She had been experiencing a persistent headache without a known cause, which did not improve despite medication.

Persistent trigeminal artery in a patient with moyamoya disease:a case report and literature review

BACKGROUNDS

Persistent trigeminal artery (PTA) is a rare anastomosis between internal carotid artery (ICA) and basilar artery. In rare conditions, the PTA could be combined with others cerebrovascular anomalies, moyamoya disease (MMD) is one of them.

CASE PRESENTATION

Here, we reported one rare case of MMD associated with PTA, the patient admitted to our department for severe dizziness and headache, imaging examination suggested MMD combined with right PTA, which arising from the ipsilateral cavernous portion of ICA. The patient received phased bilaterral revascularization with no any complication. In the subsequent follow-up, the patient's symptoms and intracranial vascular condition gradually improved. Moreover, we conducted a literature review of coexistence of PTA and MMD, the results of a web of science regarding such condition, and a deep discussion providing brief insight into the status of co-occurrence of PTA and MMD, including its manifestation, treatment and outcome.

CONCLUSIONS

The coexistence of PTA and MMD was rarely reported, the pathogenesis of such condition remains unknown. We found that the features of the coexistence of PTA and MMD were diverse, revascularization might be a feasible for such patient.

New variant of persistent primitive trigeminal artery associated with duplicated basilar artery: a radiological case report

PURPOSE

This article reports a new variant of the persistent primitive trigeminal artery. This variant does not exist in Salas and Saltzman classifications.

METHODS

We analyzed CTA images of a 39-year-old male patient using RadiAnt. This work had clinical and research purposes.

RESULTS

A persistent primitive trigeminal artery arose from left internal carotid artery termination. Its course was atypical, superior, and lateral to the sella turcica. At its end, it joined a duplicated basilar artery. These morphological features are new compared to Salas and Saltzman's variants.

CONCLUSION

Anatomists, radiologists, and neurosurgeons must know this new variant. Angiographic analysis of this variant will keep the patient safe and perform the surgery. This new variant deserves to be considered in Salas and Saltzman classifications as a new type.

Case report: Spontaneous carotid-cavernous fistula associated with persistent primitive trigeminal artery aneurysm rupture

Background

The incidence of carotid cavernous fistula (CCF) associated with persistent primitive trigeminal artery (PPTA) aneurysm rupture is extremely rare. We presented a case about a spontaneous CCF secondary to a ruptured PPTA aneurysm, which was successfully embolized with coils and onyx-18 by a trans-arterial approach.

Case presentation

A 55-year-old female suffered a sudden onset of headache, left orbital pain, and pulsatile exophthalmos for a month without any history of trauma. Angiography revealed a left-sided CCF associated with a ruptured PPTA aneurysm, with major drainage to the ipsilateral superior ophthalmic vein. Through a trans-arterial approach, the fistula and ruptured PPTA aneurysm were embolized with coils and onyx-18, while the cavernous sinus and PPTA were well-preserved. However, the preserved PPTA vanished at 4 month follow-up. The patient had no neurological deficit from hospitalization to 1 year follow-up period.

Conclusion

Trans-arterial approach was a reasonable choice for spontaneous CCF associated with ruptured PPTA aneurysm. The requirement for PPTA preservation depended on individual evaluation.

Hybrid surgery for coexistence of cerebral arteriovenous malformation and primitive trigeminal artery: A case report and literature review

The primitive trigeminal artery (PTA), an abnormal carotid-basilar anastomosis, forms the vascular anomaly connection between the internal carotid artery and vertebrobasilar system. Rarely, PTA can be complicated by several other cerebrovascular disease, including arteriovenous malformations (AVMs), intracranial aneurysms, moyamoya disease, and carotid-cavernous malformations. Herein, we reported a rare case of PTA combined with an AVM in a male patient. The patient was a 28-year-old male with epileptic seizures at the onset of symptoms. Magnetic resonance imaging showed abnormal signal foci and localized softening foci formation with gliosis in the right parietal temporal lobe. Furthermore, using a digital subtraction angiogram (DSA), it was found that an abnormal carotid-basilar anastomosis had developed through a PTA originating from the cavernous portion of the right internal carotid artery (ICA) and a large AVM on the surface of the right carotid artery. The lesion of AVM tightly developed and draining into superior sagittal sinus. A hybrid operating room was used for the surgery. The main feeding arteries of the AVM originating from three major arteries, including the right middle cerebral artery, the right anterior cerebral artery, and the right posterior cerebral artery, were clipped and subsequently, then the AVM was thoroughly removed. The intraoperative DSA showed that the AVM had been resected completely. Postoperative pathological examination of the resected specimen indicated the presence of an AVM. The patient recovered well after surgery and has been symptom-free for more than 3 months. In summary, the pathogenesis of the coexistence of PTA and AVM remains unknown. As highlighted in this case report, hybrid surgery can be used to remove AVMs and can improve the patients' prognosis. To our best knowledge, this is the first case in the literature of successful AVM treatment using hybrid surgery.

A Study on the Persistent Trigeminal Artery and Its Classification Based on Magnetic Resonance Angiograph Images

BACKGROUND

The persistent trigeminal artery (PTA) is the most common remnant of primitive circulation, communicating the developing carotid and vertebrobasilar junction.

PURPOSE

This study aimed to evaluate the implementation of magnetic resonance angiography for the detection of PTA and to reclassify the variations based on Weon typing. Moreover, the correlation of various Weon types with the posterior cerebral artery (PCA), Willis ring, basilar artery (BA) dysplasia, and the relationship between PTA and arteriosclerosis were analyzed.

METHODS

From November 2017 to October 2019, a total of 48,184 patients underwent magnetic resonance angiography examination in our hospital, and 79 patients were diagnosed with PTA. Of these, 70 patients with complete radiological and clinical information were included in this study.

RESULTS

Among the 70 patients with complete data, 27 were classified as Weon type I (38.6%), 7 as type II (10%), 14 as type III (20%), 8 as type IV (11.4%), and 3 as type V (4.3%: type Va, 1 case; type Vb, 2 cases). The remaining 11 cases were PCA with mixed blood supply, so the new type VI was divided into 3 subtypes: type VIa, type VIb, and type VIc, and each subtype of type V was further refined into 4 subtypes. There were 32 cases of PTA with BA dysplasia, including 14 with type I (51.9%), 5 with type II (71.4%), 2 with type III (14.3%), 5 with type IV (62.5%), and 6 with type VI (54.5%). Cerebral infarction was found in 55 cases (78.6%) of PTA, among which 11 had a cerebral infarction in the posterior circulation blood supply area. There were 46 cases (65.7%) accompanied by intracranial arteriosclerosis, and in 6 cases, arteriosclerosis mainly occurred in the posterior circulation.

CONCLUSIONS

We redefined the classification of PTA based on Weon typing for a better understanding of clinical symptoms and surgical risks. Moreover, PTA was correlated with the fetal origin of PCA, BA dysplasia, and posterior circulation arteriosclerosis. These factors may increase the incidence of cerebral infarction in the posterior circulation blood supply area.

Anatomic Variation for the Endoscopic Endonasal Transsphenoidal Approach

Knowledge of anatomy and its variations is the key to safe and efficient surgery. The endoscopic endonasal route to the sella has evolved to become the preferred route to access a wide variety of diseases. We describe the skeletal, vascular, and neural anatomic variations that could be encountered from the nasal phase, through the sphenoid phase, to the sellar phase of the operative exposure. A preoperative checklist is also provided.

Treatment of Aneurysms in Persistent Primitive Trigeminal Arteries with Stent-Assisted Coil Embolization

Objective

Persistent primitive trigeminal artery (PPTA) is a rare condition in which a fetal carotid-basilar anastomosis persists into adulthood. PPTA aneurysms often necessitate endovascular treatment and adjunctive techniques, such as stent- or balloon-assisted techniques, are sometimes selected. This case report describes two women in their sixties with unruptured right PPTA aneurysms who underwent stent-assisted coil embolization procedures, with consideration of the anatomical features in each case.

Case Presentations

One patient presented with an aneurysm at the bifurcation of the PPTA and the basilar artery (BA), which was classified as Saltzman type 1 with a hypoplastic vertebral artery (VA)-BA system. A stent was deployed from the BA to the PPTA to cover the neck of the aneurysm and coil embolization was performed. The second patient presented with an aneurysm at the bifurcation of the PPTA and the internal carotid artery (ICA), which was classified as Saltzman type 2 with a hypoplastic VA-BA system. A stent was deployed from the PPTA to the petrous segment of the ICA covering the neck of the aneurysm and coil embolization was performed. In both patients, the 1-year follow-up digital subtraction angiography (DSA) showed that the aneurysms had not recurred.

Conclusion

The PPTA aneurysms were successfully treated with stent-assisted coil embolization. The treatment strategy should be devised in accordance with both the lesion site and the PPTA variant.

A unique variant of a right persistent hypoglossal artery arising from the common carotid artery with complex cardiovascular anomalies in a female neonatal patient

Persistent primitive hypoglossal artery is a carotid-vertebrobasilar anastomosis, which commonly arises from the internal carotid artery at the level of the C (cervical) 1-3 vertebrae. We describe a unique case of a female infant patient with this anomaly that has an unusually low origin from the distal common carotid artery just below the bifurcation at the level of roughly C5 and supplies the entire vertebrobasilar system. Additional cardiovascular anatomical variations were present: Tetralogy of Fallot and a right-sided aortic arch with mirror image branching. These singular variations are rare in the general population, but even rarer when combined. Awareness of these unusual vascular variants is clinically significant, as they may predispose the patients to early ischemic injury, hemorrhage, aneurysm formation, and can be essential in surgical planning. Therefore, radiographic imaging is of importance in proper diagnosis of such variants.

Persistent Trigeminal Artery: Neuroanatomic and Clinical Relevance

INTRODUCTION

Persistent trigeminal artery (PTA) is the most common remnant of primitive circulation communicating the developing carotid and vertebrobasilar junction. Although discovered incidentally, an altered hemodynamic may lead to an increased association of aneurysms, vascular malformations, and stroke. Neurosurgeons should be aware of the presence and significance of PTA when interpreting imaging and planning interventions.

METHODS

We retrospectively reviewed all magnetic resonance angiography and cerebral digital subtraction angiography performed between 2012 and 2017 for the presence of PTA. The radiologic and anatomic details were noted and analyzed along with the clinical profiles. We categorized the radiologic findings with respect to the available classification systems. A review of the available literature was done comparing our results.

RESULTS

We found 33 cases of incidentally detected PTA. The average age of the patients was 45.42 years. The lateral surface of the proximal cavernous internal carotid artery was the most common origin (n = 23). Only 3 cases had a medial/transsellar course. Most cases were Saltzman/Weon type I (19/33). Intracranial aneurysms were associated with 6 patients (18.18%). Trigeminal neuralgia (TN) was a presenting feature in 5 patients. None had a direct neurovascular conflict at the root entry zone.

CONCLUSIONS

Our study is one of the largest to describe the incidence of PTA. We emphasized the importance of PTA to the neurosurgeons; increased association of aneurysms, as a route for intervention in occlusive disease of the posterior fossa; risk of injury and bleeding during transsphenoidal surgery; and the association with TN. However, we found that only PTA variants are likely to be associated with TN because of their cisternal course causing NV conflict.

Persistent Trigeminal Artery Playing a Protective Role in a Case of Vertebral Artery Dissection and Stenosis

Several fetal anastomoses have been described between the carotid and vertebrobasilar circulations. These anastomoses usually revert while the P1 segment (posterior cerebral artery segment 1) develops. However, these primitive intracranial embryonic anastomes can occasionally persist in adult age. Persistence of the primitive trigeminal artery (PPTA) is the most common of these persistent fetal anastomoses. Although uncommonly identified, knowledge of this structure is crucial for clinicians who analyze cranial imaging. PPTA has been associated with intracranial aneurysms and arteriovenous malformations but it is not very clear whether or not PPTA can also play a protective role in certain cases. We present the case of a 31-year-old female who suffered from a medullary stroke due to vertebral artery dissection and the persistent trigeminal artery (PTA) possibly played an important protective role since blood flow to the brainstem was preserved via a robust collateral flow from the right internal carotid artery (ICA).

Persistent primitive trigeminal artery associated with a cavernous carotid aneurysm. Case report and literature review

The persistent primitive trigeminal artery is the most common persistent carotid-vertebrobasilar anastomosis. Patients are usually asymptomatic and the persistent primitive trigeminal artery is commonly found incidentally on imaging. Rarely, they may present with symptoms of neurovascular conflict or cranial nerve compression syndromes as the artery may be intimately related to the cranial nerves. The basilar artery is often hypoplastic in this condition and blood supply to the posterior circulation is predominantly via the persistent primitive trigeminal artery. Recognizing the persistent primitive trigeminal artery is imperative as disease of the artery may result in ischemia of the posterior circulation. To date, there is no clear association between this artery and cerebral aneurysms. We present a rare case of a patient with a persistent primitive trigeminal artery and a concomitant cavernous carotid aneurysm together with a literature review.

Successful Microvascular Decompression For Trigeminal Neuralgia Secondary to a Persistent Trigeminal Artery

BACKGROUND AND IMPORTANCE

Persistent trigeminal artery (PTA) is a rare but important anatomic variant that contributes to trigeminal neuralgia (TN). Microvascular decompression (MVD) of the responsible vessel(s) away from the trigeminal nerve provides the most complete and durable relief from TN. The role and technique of MVD for TN associated with a PTA has not been fully defined in the literature. Furthermore, assessment of PTA anatomy intraoperatively with a microscope is challenging. We report the first 3-dimensional (3D) microscopic video and first intraoperative endoscopic video of a successful MVD of the trigeminal nerve in a patient who suffered TN from a tortuous, compressive PTA.

CLINICAL PRESENTATION

A 66-yr-old right-handed female presented with right facial pain in V2 and V3 distributions with a clinical picture of TN. Imaging demonstrated trigeminal nerve compression secondary to a PTA and MVD was performed with a 3D operative microscope and an endoscope. The PTA appeared to compress the nerve directly at the trigeminal porus and also had compressive superior cerebellar artery variant branches. The nerve was decompressed at all points of compression with Teflon pledgets along its entire cisternal length. Postoperatively, she is free with trigeminal pain episodes at 4-mo follow-up.

CONCLUSION

In cases of TN associated with a PTA, we recommend decompression along the entire length of the nerve wherever there is compression. Furthermore, we find both the operative microscope and particularly the endoscope useful to assess vascular anatomy intraoperatively.

Conventional MRI

Conventional magnetic resonance imaging (MRI) allows for a detailed noninvasive visualization/examination of posterior fossa structures and represents a fundamental step in the diagnostic workup of many cerebellar disorders. In the first part of this chapter methodologic issues, like the correct choice of hardware (magnets, coils), pro and cons of the different MRI sequences, and patient management during the examination are discussed. In the second part, the MRI anatomy of the cerebellum, as noted on the various conventional MRI sequences, as well as a detailed description of cerebellar maturational processes from birth to childhood and into adulthood, are reported. Volumetric studies on the cerebellar growth based on three-dimensional MRI sequences are also presented. Moreover, we briefly discuss two main topics regarding conventional MRI of the cerebellum that have generated some debate in recent years: the differentiation between cerebellar atrophy, hypoplasia, and pontocerebellar hypoplasia, and signal changes of dentate nuclei after repetitive gadolinium-based contrast injections. The advantages and benefits of advanced neuroimaging techniques, including ¹H magnetic resonance spectroscopy, diffusion-weighted imaging, diffusion tensor imaging, and perfusion-weighted imaging are discussed in the last section of the chapter.

Anomalies and Normal Variants of the Cerebral Arterial Supply: A Comprehensive Pictorial Review with a Proposed Workflow for Classification and Significance

Cerebral arteries may exhibit a wide range of variation from normal anatomy, which can be incidentally discovered during imaging. Knowledge of such variants is crucial to differentiate them from pathologies, to understand the etiology of certain pathologies directly related to a vascular variant, and to depict the changes in collateral circulation in patients with certain variants. Detection of particular variants may lead to the discovery of other nonvascular or vascular anomalies, especially aneurysms, and may also affect planning of endovascular or neurosurgical interventions. In this review, we summarize the variants and anomalies of cerebral arteries seen on cross-sectional imaging classified by a morphological approach and categorize their significance from a clinical perspective. This structured review is intended to serve as a guide for daily use in clinical practice.

Rare Variants of Carotid-Vertebrobasilar Anastomoses

Carotid-vertebrobasilar anastomoses generally disappear during embryogenesis. However, if a problem exists during regression, these arteries persist in adult period and are named as persistent arteries. Their persistence in adult patients is sometimes pathological and may result in the development of an aneurysm or a compressive syndrome. These anastomoses are frequently associated with proximal or distal arterial pathology. Herein, we present three rare variants of carotid-vertebrobasilar anastomoses: a persistent trigeminal artery, persistent hypoglossal artery, and a persistent otic artery. These variants should be kept in mind to avoid errors both in clinical reporting and surgical procedures.

Isolated intermittent vertigo: A presenting feature of persistent trigeminal artery

Embryonic carotid – basilar anastomosis when persistent in adult life can present with a variety of neurological symptoms. We present a patient with isolated intermittent vertigo attributable to the embryonic anastomosis and describe the different types of persistent trigeminal artery. A 76-year-old Caucasian man presented with isolated intermittent vertigo and symptoms suggestive of anterior and posterior circulation strokes. Impaired vasomotor reactivity was demonstrated on insonation of the anterior and posterior cerebral arteries in this patient with a persistent left trigeminal artery and 75% stenosis of the left internal carotid artery (ICA). The symptom of intermittent vertigo resolved with carotid endarterectomy. Decreased flow across the stenotic segment of the ICA which subserved the posterior circulation resulted in basilar insufficiency. Hypoperfusion to the flocculonodular lobe supplied by the anterior inferior cerebellar artery is a likely cause for the intermittent vertigo.

Pseudo subclavian steal syndrome: Case report

INTRODUCTION

Vertebrobasilar insufficiency (VBI) is a condition that results from restricted blood flow to the posterior portions of the brain, which are primarily served by the vertebral and basilar arteries. It is the most common cause of vertigo in the elderly and is usually accompanied by impaired vision and sensation. Congenital abnormalities, atherosclerosis, stroke and/or trauma may all lead to decreased vertebrobasilar circulation. A syndrome called Subclavian Steal Syndrome (SSS), which manifests with similar neurological symptoms but with a different pathophysiology, may also cause VBI.

CASE PRESENTATION

A middle-aged female presented with gradual onset fainting and vertigo attacks. Cardiac, auditory and autonomic etiologies were investigated and excluded. Clinical findings and presentation were highly suggestive of subclavian steal. However, subsequent CT angiography showed normal subclavian arteries. Instead, findings included a persistent right trigeminal artery (PTA), stenosis of the right proximal internal carotid artery, atresis of the left vertebral artery and distal segment of right vertebral artery, congenitally compromised changes in vertebral circulation (bilateral absence of the posterior communicating arteries (PCOMs)) and an absent anterograde vertebrobasilar circulation. Symptoms resolved after carotid endarterectomy.

DISCUSSION

Due to the absence of a normally developed posterior circulation, the PTA was the main source of blood supply for the patient. Development of recent artheromatous changes in the right internal carotid artery, however, resulted in decreased blood through PTA, further compromising posterior circulation. This resulted in vertebrobasilar insufficiency, and manifested in symptomology similar to SSS.

CONCLUSIONS

This clinical encounter illustrates the relative contribution of anatomical and vasoocclusive factors in closely mimicking symptoms of subclavian steal syndrome.

Unusual persistent primitive trigeminal artery with a superior duplicated basilar system

A 67-year-old patient who presented with a right cerebellar hemorrhage underwent vascular workup for suspicion of underlying vascular anomalies. A diagnostic cerebral angiogram demonstrated a duplicated basilar system fed solely by a persistent primitive trigeminal artery. The findings proved to be incidental and unrelated to the patient's hemorrhage. These developmental abnormalities are consistent with embryological development.

Function of circle of Willis

Nearly 400 years ago, Thomas Willis described the arterial ring at the base of the brain (the circle of Willis, CW) and recognized it as a compensatory system in the case of arterial occlusion. This theory is still accepted. We present several arguments that via negativa should discard the compensatory theory. (1) Current theory is anthropocentric; it ignores other species and their analog structures. (2) Arterial pathologies are diseases of old age, appearing after gene propagation. (3) According to the current theory, evolution has foresight. (4) Its commonness among animals indicates that it is probably a convergent evolutionary structure. (5) It was observed that communicating arteries are too small for effective blood flow, and (6) missing or hypoplastic in the majority of the population. We infer that CW, under physiologic conditions, serves as a passive pressure dissipating system; without considerable blood flow, pressure is transferred from the high to low pressure end, the latter being another arterial component of CW. Pressure gradient exists because pulse wave and blood flow arrive into the skull through different cerebral arteries asynchronously, due to arterial tree asymmetry. Therefore, CW and its communicating arteries protect cerebral artery and blood-brain barrier from hemodynamic stress.