Variability of the Middle Meningeal Artery Subject to the Shape of Skull

The effect of arterial spin labeling MR angiography (ASL-MRA) in visualizing the branches of external carotid artery

This study aimed to assess the performance of arterial-spin labeling MRA (ASL-MRA) for visualizing the external carotid artery (ECA) branches in comparison with time-of-flight MRA (TOF-MRA) and CT angiography (CTA). We retrospectively selected 31 consecutive patients, who underwent both MRAs and CTA, prior to the intra-arterial chemoradiotherapy (IACRT) for head and neck cancer. Four patients underwent IACRT bilaterally, so we analyzed 35 ECAs. Pseudo-continuous, three-dimensional ASL using a turbo field echo sequence was acquired. For the TOF-MRA and CTA, clinically used parameters were applied. Two observers evaluated each ECA branch with reference to the angiogram at the IACRT, using five-point scale, in consensus. Friedman test for multiple comparisons was applied. ASL-MRA and CTA better visualized the superior thyroid, lingual, facial, submental, transverse facial, and internal maxillary arteries (IMAs) better than TOF-MRA (p < 0.05). In addition, CTA was superior to ASL-MRA in visualizing only submental artery among these arteries (p = 0.0005). Alternatively, the ASL-MRA was superior for visualizing the middle meningeal artery (MMA) and IMA, compared to the CTA (p = 0.0001 and 0.0007, respectively). ASL-MRA was superior to the TOF-MRA and similar to the CTA in visualizing most of ECA branches. Furthermore, ASL-MRA can better visualize the periphery of MMA and IMA than CTA.

Anomalous branching of the middle meningeal artery from the basilar artery: a systematic review

Background

Anomalous origin of the middle meningeal artery (MMA) from the basilar artery is a rare congenital neurological variant that has been detected in both children and adults with diagnoses ranging from intracranial haemorrhage to ependymoma. This review aims to investigate the anatomical course of an anomalous basilar-middle meningeal artery and its clinical presentation.

Methods

A systematic search was performed in PubMed using the keywords (middle meningeal artery) and (basilar artery). Ninety-four papers were identified, of which seven were included. One paper was further identified through cross-referencing.

Results

The average age of presentation was 43 years with a male predominance (7/9). In most cases, the MMA arose between the superior cerebellar artery and the anterior inferior cerebellar artery (8/9) (versus 1 case between the anterior inferior cerebellar artery and the posterior inferior cerebellar artery). The anomaly mostly presented on the left side (6/11), but was bilateral in one case. Most of the cases showed a pontine artery branching from the basilar artery arising 5 mm to 10 mm proximal to the superior cerebellar artery, which would then assume the trajectory of the MMA. In three cases, the vessel increased in calibre near the trigeminal ganglion. Foramen spinosum absence in the anomalous side was noted in 3/6 of the patients.

Conclusion

To avoid unexpected complications during neurosurgical and neuroradiointerventional procedures, it is essential to have a clear understanding of the anomalous routes of the MMA. This is especially important when it proves to be the only available route for embolization.

Comprehensive anatomical study of meningeal arteries in dromedaries

This study provides a detailed, in-depth analysis of the anatomy, topography, and branching patterns of the meningeal arteries in dromedary camels, a subject that has not previously been thoroughly studied in animals, providing insight into the intricate biological adaptations that allow them to survive in harsh environments. By precisely examining 20 heads obtained from freshly slaughtered dromedaries, we revealed the origins and topologies of the rostral, middle, and caudal meningeal arteries using advanced casting techniques for precise rendering. Our findings indicate that the rostral meningeal artery derives from the external ethmoidal artery and primarily supplies the rostrodorsal region of the frontal lobe. The middle meningeal artery provides blood to approximately two-thirds of the brain meninges. The caudal meningeal artery is derived from the occipital artery and supplies the meninges covering the cerebellum, caudal part of the falx cerebri, and tentorium cerebelli. Significantly, our study revealed the presence of accessory branches originating from the rostral epidural rete mirabile, a finding not previously described in the existing literature. These branches supply the meninges of the frontal and lateral regions of the frontal lobes. This novel study advances our understanding of the meningeal arteries in dromedaries and has significant implications for advancements in veterinary neuroscience.

Spontaneous Middle Meningeal Artery Aneurysms: A Case Report and Review of the Literature

Most reported aneurysms concerning the middle meningeal artery (MMA) are pseudoaneurysms; however, there have been rare reports of non-traumatic MMA aneurysms in the literature. In this paper, we present the case of a 70-year-old female with a true 5-mm aneurysm in the anterior division of the left MMA that was causing erosion through the left temporal bone and was successfully treated with coil embolization. We also present a comprehensive literature review of non-traumatic MMA aneurysms reported since 1930. These aneurysms are associated with conditions such as hypertension, Paget's disease, and intracranial meningiomas and result from flow dynamics disturbances. Treatment involves both endovascular treatment and open surgery, while rupture, especially in the elderly, results in high disability, underscoring the importance of timely intervention upon identification.

Phenotypical variability of the internal acoustic canal in the middle cranial fossa surgery

Introduction: The wide range of anatomical variability of the structures of the middle cranial fossa and the lack of reliable surgical landmarks contribute to a high level of complications in the surgical treatment of vestibular schwannomas. We hypothesized that the cranial phenotype influences the shape of the middle cranial fossa, the orientation of the pyramid of the temporal bone, and the relative topography of the internal acoustic canal. Materials and Methods: The skull base structures were studied on 54 embalmed cadavers and 60 MR images of the head and neck by photo modeling, dissection, and 3D analysis techniques. By the value of the cranial index, all specimens were subdivided into dolichocephalic, mesocephalic, and brachycephalic groups for comparison of variables. Results: The length of the superior border of the temporal pyramid, the apex to squama distance, and the width of the middle cranial fossa all peaked in the brachycephalic group. The value of the angle between the superior border of the pyramid and the axis of the acoustic canal varied from 33 to 58 º; it peaked in the dolichocephalic group and showed its smaller value in the brachycephalic one. The pyramid to squama angle had reversed distribution and dominated in the brachycephalic group. Conclusions: The cranial phenotype influences the shape of the middle cranial fossa, temporal pyramid, and internal acoustic canal. Presented in this paper data help specialists operating on the vestibular schwannoma to localize the internal acoustic canal based on the individual shape of a skull.

The Appearance of Middle Meningeal Artery Fistulae After Willis Covered Stent for Traumatic Carotid-cavernous Fistulae: Two Case Reports

INTRODUCTION

Carotid cavernous fistulae (CCF) are rare, and they occur when there is a communication between the internal carotid artery (ICA) and cavernous sinus. These lesions are associated with blunt or penetrating traumatic injuries of the carotid arteries. We present the first cases of cavernous dural arteriovenous fistulae (cDAVF) in the middle meningeal artery (MMA) after the treatment of direct CCF in the ICA with Willis-covered stents (WCSs).

CASE PRESENTATION

Our patients comprised 22 and 50-year-old males with histories of head injuries months before admission at our facility. In both patients above, cerebral angiography revealed fistulae in the right ICA and left ICA, respectively. They were treated with WCSs via the trans-artery endovascular route. In both cases, the treatments were not in the way attempted via the MMA. Subsequently, they developed cDAVF in the middle meningeal artery (MMA), which were treated with Onyx Liquid Embolic System (Onyx HD-500) (Covidien / ev3 Neurovascular) and conservatively, respectively.

CONCLUSION

These are the first cases in whom WCSs for the management of direct CCF resulted in cDAVF at the MMA. The WCSs inside the ICA could have resulted in the cDAVF via unknown mechanisms but not iatrogenic.

Imaging features of internal maxillary artery and extracranial middle meningeal artery and their relationships on head CTA

BACKGROUND

The internal maxillary artery and extracranial middle meningeal artery are vitally important. Anatomical studies of the relationship of between them using computed tomography angiography are rare.

MATERIAL AND METHODS

This study assessed 75 cases involving 150 sides. And the vascular diameters and lengths of the internal maxillary artery and middle meningeal artery were measured using a GE workstation. The distance between the zygomatic arch midpoint and the internal maxillary artery, the angle between the internal maxillary artery and middle meningeal artery were measured, and the middle meningeal artery branch and internal maxillary artery aneurysm were recorded. The internal maxillary artery course classifications were recorded. All of these parameters were statistically analysed.

RESULTS

Ages ranged from 18 to 72 (average 40.2) years, and there were 30 women (40%, 30/75) and 45 men (60%, 45/75). Internal maxillary artery length from its origin to middle meningeal artery origin was 1.37 ± 0.59 cm. The extracranial middle meningeal artery length was 1.79 ± 0.48 cm. The vessel diameters of internal maxillary artery origin, middle meningeal artery origin, and middle meningeal artery at the skull base were 2.93 ± 0.52 mm, 1.58 ± 0.43 mm, and 1.33 ± 0.43 mm, respectively. Among the 150 sides of internal maxillary artery course type, there were 138 superficial (92%, 138/150) and 12 (8%, 12/150) deep course cases. The angle between the internal maxillary artery and middle meningeal artery was 116.2 ± 35.76°.

CONCLUSIONS

The findings of this study elucidate the imaging features of the internal maxillary artery and extracranial middle meningeal artery and their relationships, which are helpful for the extracranial-intracranial bypass and endovascular treatment via the internal maxillary artery and middle meningeal artery.

Proximity of the middle meningeal artery and maxillary artery to the mandibular head and mandibular neck as revealed by three-dimensional time-of-flight magnetic resonance angiography

Purpose

The close topographic relationship between vascular and osseous structures in the condylar and subcondylar region and marked variability in the arterial course has been revealed by both imaging and cadaveric studies. This study aimed to verify the previously published information in a large sample and to determine a safe surgical region.

Methods

We analyzed the three-dimensional time-of-flight magnetic resonance angiography images of 300 individuals.

Results

The mean distance between the middle meningeal artery and the apex of the condyle or the most medial point of the condyle was 18.8 mm (range: 11.2–25.9 mm) or 14.5 mm (range: 8.8–22.9 mm) respectively. The course of the maxillary artery relative to the lateral pterygoid muscle was medial in 45.7% of cases and lateral in 54.3%. An asymmetric course was evident in 66 patients (22%). The mean distance between the maxillary artery and condylar process at the deepest point of the mandibular notch was 6.2 mm in sides exhibiting a medial course (range: 3.7–9.8 mm) and 6.6 mm in sides exhibiting a lateral course (range: 3.9–10.4 mm). The distances were significantly influenced by age, gender, and the course of the maxillary artery.

Conclusion

Our study emphasizes the marked inter- and intra-individual variability of the maxillary and middle meningeal arterial courses. We confirmed the proximity of the arteries to the condylar process. Extensive surgical experience and thorough preparation for each individual case are essential to prevent iatrogenic vascular injury.

Bony Tunnel Formation Associated with the Distal Segment of the Frontal Branch of the Middle Meningeal Artery

The knowledge of certain anatomical variations is fundamental and any surgeon who operates without that knowledge may encounter difficulty during surgery. In this context, there is the middle meningeal artery (MMA) which also engenders considerable clinical interest due to its location. The MMA is predominantly periosteal, irrigating the bone and dura mater. It enters the floor of the middle cranial fossa through the foramen spinosum, travels laterally through a middle fossa bony ridge, and curves anteriorly over the upper-greater wing of the sphenoid where it divides into parietal and frontal branches at a variable point. Occasionally, the distal segment of the frontal branch may pass through a bony tunnel of variable size. To the best of our knowledge, there is no evidence in the current literature on the incidence of this rare bony tunnel. Therefore, we decided to investigate the incidence of this bony tunnel in 85 dry skulls of adults (both genders) belonging to the didactic collection of the Human Anatomy Laboratory of the Universidade de Santa Cruz do Sul, Brazil. All the skulls were examined bilaterally for the presence or absence of the bony tunnel associated with the distal segment of the frontal branch of the MMA. Of the 85 skulls analyzed, the bony tunnel was present on the right side in 1.18% and on the left side in 5.88% ( p  = 0 .045 ). Thus, in the studied sample, there was a significant tendency for this bony tunnel to be formed on the left side.

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.

Ultra-high field MR angiography in human migraine models: a 3.0 T/7.0 T comparison study

BACKGROUND

Sildenafil and calcitonin gene-related peptide both dilate the intradural segments of the middle meningeal artery measured with 3.0 tesla (T) MR angiography. Here we hypothesized that an increase in field strength to 7.0 T and concomitant enhanced voxel resolution would lower variance in measurements of dilation in the intradural middle meningeal artery.

METHODS

Five subjects completed two sessions at respectively 3.0 T and 7.0 T. Each session comprised MR angiography scans once before and twice after administration of sildenafil, calcitonin gene-related peptide or placebo in a three-way, crossover, double-blind, placebo-controlled design.

RESULTS

Standard deviations of arterial circumference revealed no difference between 3.0 T and 7.0 T measurements (p = 0.379). We found a decrease in standard deviation from our original angiography analysis software (QMra) to a newer (LAVA) software package (p < 0.001). Furthermore, we found that the dilation after sildenafil and calcitonin gene-related peptide were comparable between 3.0 T and 7.0 T.

CONCLUSIONS

Our findings suggest no gain from the increase in voxel resolution but cemented dilatory findings from earlier. The implemented software update improved variance in circumference measurements in the intradural middle meningeal artery, which should be exploited in future studies.

TRIAL REGISTRATION

The study is part of a parent study, which is registered at ClinicalTrials.gov ( NCT03143465 ).

Perivascular neurotransmitters: Regulation of cerebral blood flow and role in primary headaches

In order to understand the nature of the relationship between cerebral blood flow (CBF) and primary headaches, we have conducted a literature review with particular emphasis on the role of perivascular neurotransmitters. Primary headaches are in general considered complex polygenic disorders (genetic and environmental influence) with pathophysiological neurovascular alterations. Identified candidate headache genes are associated with neuro- and gliogenesis, vascular development and diseases, and regulation of vascular tone. These findings support a role for the vasculature in primary headache disorders. Moreover, neuronal hyperexcitability and other abnormalities have been observed in primary headaches and related to changes in hemodynamic factors. In particular, this relates to migraine aura and spreading depression. During headache attacks, ganglia such as trigeminal and sphenopalatine (located outside the blood-brain barrier) are variably activated and sensitized which gives rise to vasoactive neurotransmitter release. Sympathetic, parasympathetic and sensory nerves to the cerebral vasculature are activated. During migraine attacks, altered CBF has been observed in brain regions such as the somatosensory cortex, brainstem and thalamus. In regulation of CBF, the individual roles of neurotransmitters are partly known, but much needs to be unraveled with respect to headache disorders.

The Value of the Middle Meningeal Artery in Cerebrovascular Bypass Surgery: An Anatomic Feasibility Study

BACKGROUND

Over the past decade, there has been a revival and a renewed interest for cerebrovascular bypass procedures. The superficial temporal artery (STA) has its value as a reliable donor vessel; however, a possible role for the middle meningeal artery (MMA) as a donor artery is still unclear.

OBJECTIVE

To assess the feasibility of using the MMA as a donor vessel in cerebrovascular surgery.

METHODS

We performed cadaveric dissections on 12 fresh specimens (23 sides) after bilateral silicone injection into the internal and external carotid arteries. We compared the size, diameter, and possibility to perform a bypass to the middle cerebral artery for both the MMA and the STA. Measurements were done using an electrical caliper. Additional measurements of the MMA and STA were performed on 20 random angiograms.

RESULTS

There was no statistically significant difference in diameter of the MMA at its ostium being 2.4 mm, compared to 2.7 mm for the STA ostium (t-test; P = .21). The MMA could be mobilized over 4.1 cm, whereas the STA over 8.3 cm. Finally, the mean diameter of the donor vessel at the site of the anastomosis was 1.6 mm versus 1.9 mm for MMA and STA, respectively (P = .0026). We were able to perform an MMA and middle cerebral artery anastomosis on 17 sides.

CONCLUSION

These results suggest that the MMA is a potentially valuable donor vessel to be used in selected cases. The availability of a suitable MMA branch should be assessed preoperatively on the angiogram.

Traumatic arteriovenous fistula between the extracranial middle meningeal artery and the pterygoid plexus: A case report and literature review

The formation of a traumatic arteriovenous fistula (AVF) between the extracranial middle meningeal artery (MMA) and the pterygoid plexus (PP) is very rare, and understanding of this condition is limited. This paper reports the case of an 8-year-old who suffered minor injuries after a high fall four months prior to admission and showed good recovery after one month. However, the child gradually developed exophthalmos of the left eye and conjunctival redness one month prior to admission. Auscultation revealed an intracranial murmur near the left side of the face, in the temporal region. A digital subtraction angiography (DSA) showed rupture of the left extracranial MMA and an AVF between the MMA and the PP. The blood drained toward the cavernous sinus, resulting in retrograde blood flow into the ophthalmic vein and the cortical vein. The diagnosis was an AVF between the MMA and the PP, and a combination of coils and Onyx liquid embolic agent was employed to perform AVF embolization. Follow-up six months later indicated no recurrence of the AVF, and the patient showed good recovery with a normal-appearing left eye. The AVF in this case drained toward the cavernous sinus, and symptoms of increased intracranial venous system pressure were apparent, similar to those produced by fistulas between the internal carotid artery and the cavernous sinus. This condition is very rare, and the use of coils in combination with Onyx for AVF embolization is novel, warranting the reporting of the current case.

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.