Absence and Duplicate Foramen Spinosum in the Same Patient: An Extremely Rare Variation.

The foramen spinosum, one of the important openings at the base of the cranium, is the opening through which the middle meningeal artery enters the cranium. The variations of the foramen spinosum should be well known to be an important landmark in middle fossa surgeries and to understand better the clinical conditions related to the middle meningeal artery passing through it. A total of 35 bones (32 cranial base and 3 separate sphenoid bones) of individuals of unknown age, sex, and ethnicity in the Laboratory of the Department of Anatomy, Gaziantep University, Faculty of Medicine were examined bilaterally in this study. One of the 35 bones was found to have a duplicated foramen spinosum on the left side and an absence foramen spinosum on the right side. Foramen spinosum variations should be considered in middle fossa approaches and procedures involving the middle meningeal artery.

Persistent Stapedial Artery Resulting in Direct Communication Between the Middle Meningeal and Basilar Arteries: Clinical Image.

A persistent stapedial artery originates from the petrous segment of the internal carotid artery due to failure of the regression of the embryonic stapedial artery. During embryologic development, the stapedial artery supplies the middle meningeal artery through the ventral pharyngeal artery. The presence of a persistent stapedial artery can result in direct communication between the basilar and middle meningeal arteries. We present a cerebral angiogram image of an adult patient that shows a right-sided persistent stapedial artery with communication between the right middle meningeal and basilar arteries. It is important to recognize such rare anatomic variants during endovascular interventions to avoid catastrophic complications such as nontarget embolization of the posterior circulation.

Lateral Variant of Davidoff and Schechter Dural Arteriovenous Fistula.

Dural arteriovenous fistulas represent a distinct direct pathological connection between dural arterial feeders of the meninges to cortical veins or sinuses. Vascular supply of the meninges is provided by a series of named arteries-anterior, middle, and posterior meningeal arteries, with the tentorium provided by the artery of Bernasconi and Cassinari (anterior-medial) and the artery of Davidoff and Schechter (posterior-medial). This case is the first report in the literature of a lateral distal posterior cerebral artery supplying the meninges and contributing dural feeders to a Cognard type III/Borden type III dural arteriovenous fistula.

Stapedial Artery: From Embryology to Different Possible Adult Configurations.

The stapedial artery is an embryonic artery that represents the precursor of some orbital, dural, and maxillary branches. Although its embryologic development and transformations are very complex, it is mandatory to understand the numerous anatomic variations of the middle meningeal artery. Thus, in the first part of this review, we describe in detail the hyostapedial system development with its variants, referring also to some critical points of ICA, ophthalmic artery, trigeminal artery, and inferolateral trunk embryology. This basis will allow the understanding of the anatomic variants of the middle meningeal artery, which we address in the second part of the review.

Middle Meningeal Artery: Anatomy and Variations.

The middle meningeal artery is the major human dural artery. Its origin and course can vary a great deal in relation, not only with the embryologic development of the hyostapedial system, but also because of the relationship of this system with the ICA, ophthalmic artery, trigeminal artery, and inferolateral trunk. After summarizing these systems in the first part our review, our purpose is to describe, in this second part, the anatomy, the possible origins, and courses of the middle meningeal artery. This review is enriched by the correlation of each variant to the related embryologic explanation as well as by some clinical cases shown in the figures. We discuss, in conclusion, some clinical conditions that require detailed knowledge of possible variants of the middle meningeal artery.

Bilateral persistent stapedial arteries associated with unilateral moyamoya disease: a particular anatomic variant.

PURPOSE: The persistence of the stapedial artery is a rare vascular variant that could explain the origin of the middle meningeal artery from the petrous segment of the internal carotid artery. The anatomic variations are illustrated and a summary of the possible hypothesis of the origin of the middle meningeal artery from the internal carotid artery is discussed, analysing the embryological works of the Carnegie Institute and the vascular development of the middle meningeal. METHODS AND RESULTS: The authors present a young patient showing a particular vascular variant on diagnostic imaging. These showed a bilateral internal carotid artery that gives origin of the middle meningeal artery in a patient affected by moyamoya disease. A literature review was performed to analyze the particular variant of the radiologic anatomy. CONCLUSION: The internal carotid artery origin of the middle meningeal artery is a wonderful anatomic variant that permits to understand the complex embryological development and then involution of the stapedial artery.

Bilateral anomalous origin of ophthalmic artery from middle meningeal artery and coincidence of bilateral carotid artery aneurysm: Case report and literature review.

Ophthalmic artery (OA) is known for anomalous origin and aberrant course probably attributable to its complex embryology. Anomalous origin of OA can be associated with intracranial aneurysm. Anomalous origins have been reported from middle meningeal artery (MMA), cavernous carotid, posterior communicating, anterior cerebral and basilar artery. Even though bilateral anomalous origin of OA from MMA is a rare finding, to the author's best knowledge, association of above condition with bilateral internal carotid artery aneurysms has not been described in the literature. We present a case of such anomalous bilateral OA originating from MMA and associated with bilateral internal carotid artery aneurysms. We have also reviewed the pertinent literature regarding anomalous OA origin.

Anomalous "Middle" Meningeal Artery from Basilar Artery and Implications for Neuroendovascular Surgery: Case Report and Review of Literature.

BACKGROUND: The middle meningeal artery (MMA) is an important conduit for the endovascular treatment of skull base and intracranial pathologies including, recently, subdural hematomas. A key aspect of such procedures is to perform a thorough diagnostic angiogram to detect anomalous arterial origins and "dangerous" anastomoses with branches of the internal carotid arteries. Although the most common anomaly related to the MMA is an abnormal origin from the ophthalmic artery, anomalous origin from the posterior circulation is rare. Moreover, its recognition requires a concerted effort at performing a vertebral artery angiogram irrespective of the location of the pathology (e.g., in subdural hematoma). CASE DESCRIPTION: We describe a case of anomalous origin of MMA from the basilar artery as a lateral pontine artery branch that was detected in a patient with recurrent subdural hematoma who presented for endovascular MMA embolization. CONCLUSIONS: The embryologic origin of the entity is briefly discussed, along with suggestions for managing such an anomaly during endovascular embolization.

Carotid-anterior cerebral artery (ACA) anastomosis associated with azygos ACA and ophthalmic artery arising from the middle meningeal artery: a case report.

Among variations of the anterior cerebral artery (ACA), anastomosis of its A1-A2 junction with the ophthalmic segment of the internal carotid artery is rare and described as carotid-ACA anastomosis or infraoptic course of the ACA. One common variant, an azygos ACA, demonstrates no pairing of the A2 segment. To our knowledge, association of a carotid-ACA anastomosis with an azygos ACA is not reported in the English-language literature. We report a case diagnosed by magnetic resonance angiography in which right carotid-ACA anastomosis was associated with an azygos ACA and the right ophthalmic artery originated from the middle meningeal artery.

Traumatic Arteriovenous Fistula Between Extracranial Middle Meningeal Artery and Petrosal Vein.

BACKGROUND: The incidence of traumatic arteriovenous fistula (TAVF) between the middle meningeal artery (MMA) and the petrosal vein (PV) is rare. Although TAVF has been reported involving the MMA several sinus and veins, this is the first incidence of a fistula involving the extracranial MMA and PV. CASE DESCRIPTION: We present a 47-year-old male with sudden onset of weakness of his right limb and speech difficulty a few hours before admission to our facility. He had a 6-month history of mild traumatic head injury. Initial computed tomography revealed midbrain hemorrhage while digital subtraction angiography revealed a TAVF of the left MMA. Enhanced magnetic resonance imaging, however, revealed communication between the MMA and PV. We treated the patient with coil embolization via the transarterial route. CONCLUSIONS: This is the first incidence of a fistula connecting the extracranial MMA and PV. We managed the patient with only coil embolization without any further neurologic deficits.

Incidental ethmoidal dural arteriovenous fistula coexisting with a pituitary adenoma exacerbating post-transsphenoidal epistaxis.

A 64 year-old man with pituitary adenoma developed massive epistaxis after an uneventful endoscopic transsphenoidal surgery. Angiography showed extravasation from the sphenopalatine artery, to which embolisation was performed. An incidentally coexisting ethmoidal dural arteriovenous fistula supplied by the ophthalmic artery aberrantly originated from the middle meningeal artery caused increased haemorrhage.

Posterior Meningeal Artery Origin Patterns among 300 Cases and Their Clinical Importance.

BACKGROUND AND PURPOSE: The posterior meningeal artery (PMA) is known as a dura mater-nourishing vessel. We encountered a patient with Wallenberg syndrome during transarterial embolization of the PMA associated with the dural arteriovenous fistula (DAVF). METHODS: After development of Wallenberg syndrome in the patient, we assessed origins of the PMA patterns in 300 cases and divided them into 3 types. CASE PRESENTATION: A 63-year-old man was incidentally diagnosed as having transverse-sigmoid sinus DAVF with a cortical venous reflux. During the transarterial embolization, the patient complained of vertigo and numbness of the right extremities. Postoperatively, the patient exhibited Wallenberg syndrome. Diffusion-weighted magnetic resonance imaging showed a high-intensity area on the lateral side of the right medulla. CONCLUSIONS: While performing arterial embolization of the PMA that directly originates from the intracranial vertebral artery, the possibility of deficient brainstem nourishment must be considered.

Clinical importance of the middle meningeal artery: A review of the literature.

The middle meningeal artery (MMA) is a very important artery in neurosurgery. Many diseases, including dural arteriovenous fistula (DAVF), pseudoaneurysm, true aneurysm, traumatic arteriovenous fistula (AVF), moyamoya disease (MMD), recurrent chronic subdural hematoma (CSDH), migraine and meningioma, can involve the MMA. In these diseases, the lesions occur in either the MMA itself and treatment is necessary, or the MMA is used as the pathway to treat the lesions; therefore, the MMA is very important to the development and treatment of a variety of neurosurgical diseases. However, no systematic review describing the importance of MMA has been published. In this study, we used the PUBMED database to perform a review of the literature on the MMA to increase our understanding of its role in neurosurgery. After performing this review, we found that the MMA was commonly used to access DAVFs and meningiomas. Pseudoaneurysms and true aneurysms in the MMA can be effectively treated via endovascular or surgical removal. In MMD, the MMA plays a very important role in the development of collateral circulation and indirect revascularization. For recurrent CDSHs, after burr hole irrigation and drainage have failed, MMA embolization may be attempted. The MMA can also contribute to the occurrence and treatment of migraines. Because the ophthalmic artery can ectopically originate from the MMA, caution must be taken to avoid causing damage to the MMA during operations.

Carotid-Anterior Cerebral Artery Anastomosis Associated with Paraclinoid Aneurysm and Ophthalmic Artery Originating From Middle Meningeal Artery: Case Report and Consideration of Terminology.

BACKGROUND: We summarized 63 cases of anterior cerebral artery (ACA) anomaly with an infraoptic course reported in the literature including abstracts written in English. All cases were reported individually, with a maximum of 3 cases. This report describes our findings in another case and opinions regarding the terminology. CASE DESCRIPTION: A 78-year-old woman presented with subarachnoid hemorrhage. A carotid angiogram showed a right paraclinoid aneurysm with an anomaly of the ACA. The right ACA originated from the internal carotid artery at the level of the ophthalmic segment intradurally with an infraoptic course. The right ophthalmic artery originated from the ipsilateral middle meningeal artery. We performed an emergent endovascular coil embolization with balloon assistance, and the patient recovered well. CONCLUSIONS: Use of the terminology "infraoptic course of the ACA" versus "carotid-ACA anastomosis" was discussed. Based on the literature reports, at least one third of the cases have a normal-positioned ACA rather than the infraoptic ACA. Also, based on embryogenesis, it is thought that the infraoptic ACA is not a misplaced A1 segment, but rather persistence of an embryologic vessel. Therefore, based on the literature and embryology, we prefer the term "carotid-ACA anastomosis" rather than "infraoptic ACA." However, as a morphologic and positional description, the term "infraoptic ACA" has value. To the best of our knowledge, the present case of a carotid-ACA anastomosis associated with a paraclinoid aneurysm and ophthalmic artery originating from the middle meningeal artery is the first to appear in the literature.

Evaluation of Intracranial Dural Arteriovenous Fistulas: Comparison of Unenhanced 3T 3D Time-of-flight MR Angiography with Digital Subtraction Angiography.

PURPOSE: We compared gross characterization of intracranial dural arteriovenous fistulas (DAVFs) between unenhanced 3-tesla 3-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography (MRA) and digital subtraction angiography (DSA). METHODS: We subjected 26 consecutive patients with intracranial DAVF to unenhanced 3T 3D TOF MRA and to DSA. Two independent sets of observers inspected the main arterial feeders, fistula site, and venous drainage pattern on MRA and DSA images. Interobserver and intermodality agreements were assessed by k statistics. RESULTS: Interobserver agreement was excellent for fistula site (κ = 0.919; 95% confidence interval [CI], 0.805 to 1.000), good for main arterial feeders (κ = 0.711; 95% CI, 0.483 to 0.984), and very good for venous drainage (κ = 0.900; 95% CI, 0.766 to 1.000). Intermodality agreement was excellent for fistula site (κ = 0.968; 95% CI, 0.906 to 1.000) and good for main arterial feeder (κ = 0.809; 95% CI, 0.598 to 1.000) and venous drainage (κ = 0.837; 95% CI, 0.660 to 1.000). CONCLUSION: Gross characterization of intracranial DAVF was similar for both imaging modalities, but unenhanced 3T 3D TOF MRA cannot replace DSA.

Arteriovenous fistula of the middle meningeal artery--a rare complication after arthroscopic temporomandibular joint surgery readily amenable to endovascular treatment.

The development of a traumatic arteriovenous fistula after arthroscopic surgery of the temporomandibular joint (TMJ) is an unusual event that has been limited to a few case reports. These have generally involved the superficial temporal artery and surrounding venous outlets. No cases of either postoperative or post-traumatic arteriovenous fistulas involving the extracranial middle meningeal artery (MMA), which is located on the medial surface of the TMJ, have been previously reported. We report, to our knowledge, the first case of this unusual complication and describe its successful endovascular management.

Unilateral absence of foramen spinosum with bilateral ophthalmic origin of the middle meningeal artery: case report and review of the literature.

Bilateral ophthalmic origin of the middle meningeal artery with an unilateral absence of foramen spinosum has not yet been described. We report on a skull with endocranial meningeal grooves indicating bilateral ophthalmic origin of the middle meningeal artery, however, its branches were normal both in their position and distribution. In addition, a rare venous sinus variation was present unilaterally - a sinus of Hyrtl. Imaging identification of the anomalous origin of the middle meningeal artery is important while planning surgical and endovascular interventions in the middle cranial fossa and the orbit.

Persistent stapedial arteries in human: from phylogeny to surgical consequences.

The stapedial artery is an embryonic artery which disappears during the tenth week in utero, in human species. During its short life, this artery shapes the stapes and transforms the middle meningeal artery from the internal carotid artery to a branch of the external carotid system. Nevertheless, a persistent stapedial artery is seen in 0.2-4.8 per thousand of human adults. This persistence is usually asymptomatic but can sometimes cause pulsatile tinnitus or conductive hearing loss. Despite the risk of facial palsy, hearing loss and even hemiplegia argued by several authors, some surgeons have succeeded in coagulation without side effects. Reviewing the literature, we seek to enlighten the actual knowledge about the persistent stapedial artery to evaluate the risk to coagulate it. Embryologic studies explain the four types of persistent stapedial arteries: the hyoido-stapedial artery, the pharyngo-stapedial artery, the pharyngo-hyo-stapedial artery and aberrant internal carotid with persistent stapedial artery. Phylogenetic studies show that the stapedial artery persists in adulthood in many vertebrates. Its disappearance is therefore either a random effect or an adaptative convergence. This adaptation could be partially linked to the negative allometry of the stapes. Practically, the risk to coagulate a stapedial artery seems limited thanks to anastomoses, for example with the stylomastoid artery. The risk of hemiplegia reported is in fact an extrapolation of variation in rats' embryos. A persistent stapedial artery can therefore reasonably be coagulated, with special attention to the facial nerve, because the facial canal is always dehiscent where the artery penetrates.