Middle Meningeal Artery: Anatomy and Variations

Absence of Foramen Spinosum on Computed Tomography Scan Determines Feasibility of Middle Meningeal Artery Embolization

BACKGROUND AND OBJECTIVES

Middle meningeal artery embolization (MMAE) has emerged as a novel treatment of chronic subdural hematoma. In 0.5% of patients, however, there exists an ophthalmic origin of the middle meningeal artery (MMA) known as the recurrent meningeal artery. It is known that the recurrent MMA is associated with failure of its skeletal aperture, the foramen spinosum, to form during development. The aim of this study was to investigate MMAE feasibility as a function of the presence/absence of the foramen spinosum on preprocedure computed tomography (CT) scan.

METHODS

We performed a retrospective review of 100 consecutive patients undergoing MMAE from January 2022 to December 2023 at the Medical University of South Carolina. Preprocedure CT scan of the head was reviewed, and the presence or absence of the foramen spinosum, along with laterality, was recorded. Subsequently, angiographic studies were reviewed.

RESULTS

All patients (n = 100) had preprocedural CT scan available for review. The incidence of an absent foramen spinosum was 3% (n = 3). All absent foramen spinosum were left sided (2F, 1M). All embolization attempts in these patients were aborted due to recurrent meningeal artery. 97% of patients had patent bilateral foramen spinosum (n = 97). Two of these patients possessed partial ophthalmic contribution to the MMA (2%), and embolization was not performed. In patients with patent foramen spinosum, successful embolization was achieved in 92/97 patients (94.8%).

CONCLUSION

The review of preprocedure CT scan may serve as an opportunity to identify patients with ophthalmic arterial origin of the MMA, subverting unnecessary risks associated with catheter angiography.

Pitfalls of Preoperative Embolization for Meningiomas: A Case Report on Occult Anastomosis Between the Middle and Posterior Meningeal Arteries

Preoperative embolization facilitates meningioma resection by reducing intraoperative bleeding. The middle meningeal artery (MMA) is frequently targeted; however, the presence of occult anastomoses between the MMA and the posterior meningeal artery (PMA) and their potential involvement in ischemic complications remain poorly understood. A 61-year-old woman with no prior medical history was incidentally found to have a right parietal extra-axial tumor on magnetic resonance imaging (MRI). She was neurologically intact upon admission, but perifocal cerebral edema was observed surrounding the tumor, which measured approximately 33 mm × 27 mm × 22 mm. Given the patient's condition and life expectancy, tumor resection was planned, preceded by preoperative embolization to minimize intraoperative bleeding. Angiography identified the parieto-occipital branch of the right MMA as the primary feeder, and superselective angiography showed no evidence of anastomoses. Microparticles were injected into the MMA; however, immediately afterward, the patient became comatose and exhibited transient dysarthria. Postembolization angiography revealed retrograde visualization of the vertebrobasilar system through previously undetected MMA-PMA anastomoses. Subsequent MRI confirmed extensive ischemic lesions in the posterior lobes, hippocampus, cerebellum, and thalamus. The patient later developed right hemiparesis, clumsiness, dysarthria, and memory impairment, necessitating rehabilitation. While motor symptoms resolved within 10 days, memory disturbance persisted but improved with therapy. This case highlights the risk of ischemic complications due to occult MMA-PMA anastomoses, which may become functionally significant only during embolization, even if undetectable on preprocedural superselective angiography. This dynamic vascular response underscores the need for heightened vigilance in preoperative embolization planning. Clinicians should consider the possibility of latent anastomoses emerging intraoperatively, necessitating careful embolic agent selection and procedural modifications to minimize complications. Recognizing this risk may enhance patient safety and optimize embolization strategies for meningioma treatment.

Augmentation of Ipsilateral Middle Meningeal Artery Embolization After Unilateral Chronic Subdural Hematoma Evacuation Using a Contralateral Approach: A Case Series of 26 Consecutive Patients

BACKGROUND AND OBJECTIVES

After surgical drainage of a chronic subdural hematoma (cSDH), middle meningeal artery (MMA) embolization aids in preventing the revascularization of the cSDH membranes at the capillary level and, in turn, reaccumulation. With the MMA circulation ipsilateral to the surgical side often being disrupted, there is recruitment of collaterals from the contralateral MMA tree to the ipsilateral cSDH membranes. The aim of this study was to demonstrate the ability of additive contralateral liquid embolic (LE) injection after ipsilateral surgery to augment MMA embolization. We hypothesized that contralateral LE injection may provide additional MMA embolization to the affected ipsilateral side and increase response to treatment.

METHODS

Consecutive cases of unilateral cSDH surgery with ipsilateral MMA embolization and additive contralateral LE injection were retrospectively identified from a prospectively maintained database of the senior authors.

RESULTS

Over the study period, 26 consecutive cases of recurrent cSDH after unilateral surgery were identified. There was an average age of 73 ± 2.7 years (range 27-90 years), and 14 patients (54%) were female. All 26 patients (100%) had previous burr holes or a craniotomy. The average cSDH thickness after surgery and before embolization was 10 ± 0.3 mm, and the average midline shift was 3.5 ± 0.7 mm. Of the 26 patients who underwent bilateral MMA embolization, 96% had over-the-top contralateral-to-ipsilateral LE injection and penetration, providing additional embolization to membranes of the index ipsilateral cSDH. The average cSDH thickness on follow-up was 4 ± 5 mm and midline shift of 0.2 ± 0.7 mm. Complete cSDH resolution was achieved in 7 patients (39%). Two patients had cSDH recurrence, one of which required reoperation. There were no LE or catheter-related complications.

CONCLUSION

Contralateral MMA embolization in patients who have undergone ipsilateral cSDH evacuation and traditional ipsilateral MMA embolization allows for over-the-top LE penetration of cSDH membranes, thereby further augmenting the desired ipsilateral MMA embolization.

Contemporary Management of Subdural Hematoma

This review provides a comprehensive overview of the contemporary management strategies for acute and chronic subdural hematomas, delineating their distinct clinical characteristics, risk factors, etiologies, and treatment paradigms. Through a synthesis of current evidence and emerging trends, this review explores established therapeutic strategies alongside innovative modalities under active investigation. This article equips clinicians with a nuanced understanding of optimal care pathways for both acute and chronic subdural hematomas, thus facilitating improved patient outcomes.

Intra-arterial lidocaine administration of lidocaine in middle meningeal artery for short-term treatment of subarachnoid hemorrhage-related headaches

BACKGROUND AND PURPOSE

We report short- and intermediate-term effects on headaches with intra-arterial injection of lidocaine in the middle meningeal artery in patients with severe headaches associated with subarachnoid hemorrhage.

METHODS

We treated seven patients with intra-arterial lidocaine in doses up to 50 mg in each middle meningeal artery via a microcatheter bilaterally (except in one patient). We recorded the maximum intensity of headache (graded by 11-point numeric rating scale) prior to procedure and every day for the next 10 days or discharge, whichever came first. We identified changes in the middle meningeal artery pre- and post-intra-arterial lidocaine administration and quantified from Grade 0 (no change) to Grade 5 (severe narrowing or near occlusion of anterior and posterior dural branches or proximal middle meningeal artery that precludes adequate imaging of distal branches).

RESULTS

We observed improvement in severity of headaches of headache in all seven subarachnoid hemorrhage patients. The resolution of headache was immediate and complete in four patients, unilateral immediate resolution in one patient, and delayed complete resolution in patient. Two patients met the definition of severe headache (defined as 2 or more days with maximum pain scores of 8 or greater or need for 3 or more different analgesics for 2 or more days) post-lidocaine treatment. One of these patients had are lapse in headache with the severity matching pretreatment severity and required a second treatment. On analysis of angiographic data, there was consistent narrowing of middle meningeal arteries after administration of intra-arterial lidocaine and was graded as 5 in 2 arteries, 4 in 10 arteries, and 3 in 2 arteries.

CONCLUSIONS

We found that intra-arterial injection of lidocaine can result in consistent amelioration of headache in patients with subarachnoid hemorrhage. The therapeutic benefit may be related to vasoconstriction (reversal of vasodilation) in the middle meningeal arteries after administration of lidocaine.

Integrated multidisciplinary analysis of mobile digital radiographic acquisitions of the mummies of the hermits from the Sanctuary of Madonna della Corona (Trentino-Alto Adige, Italy - 17th to 19th century CE)

Paleoradiology has become a standard diagnostic method in the study of mummified or embalmed bodies. Among the various available techniques, computed tomography valuing for its ability to provide detailed information. However, computed tomography equipment is not always accessible to research teams, cannot be easily transported to all conservation sites, and raises health concerns. Therefore, mobile digital radiographic technology is often the most suitable investigative tool in specific contexts. In this study, three mummies preserved at the Sanctuary of Madonna della Corona, perched on a cliff above the Adige River Valley on the Monte Baldo at an elevation of 775 m a.s.l., were analyzed using radiographic techniques. The impossibility of transferring the bodies due to the sanctuary's remote location imposed the use of lightweight, portable equipment for the radiological examination. This article highlights next-generation X-ray technology utility, potential, and limitations in investigating clothing fabrics, restoration history, taphonomy, entomology, anthropology, and paleopathology. The interdisciplinary approach in this study has unveiled new historical and biological insights about these mummies, which, though revered in popular devotion, had previously been unknown to both Italian and international scientific communities.

A case of recurrent subdural hematoma after unilateral MMA embolization that resolved after contralateral MMA embolization

Middle meningeal artery embolization (MMAe) is rapidly emerging as a valuable intervention to decrease the risk of recurrent subdural hematoma (SDH) after surgical evacuation. The role of upfront bilateral MMAe for unilateral SDH and the value of contralateral MMAe after SDH recurrence post evacuation and ipsilateral MMAe are still unknown. Here, we report the case of an elderly patient that presented with a large acute on chronic SDH and underwent surgical drainage and ipsilateral MMAe (with Contour PVA particles, 150-250 µm). At one month follow-up, he was found to have a significant radiographic recurrence of the SDH with interval acute hemorrhage. Angiography revealed complete occlusion of the trunk of the previously embolized ipsilateral MMA, and the presence of robust anastomotic branches from the contralateral MMA crossing the midline to collateralize patent distal branches of the previously embolized MMA. Decision was made to proceed with contralateral MMAe, which resulted in near complete SDH resolution at 6 months follow-up.

Distribution of the Middle Meningeal Artery Variants in Patients Undergoing Embolization for Chronic Subdural Hematoma

BACKGROUND

The middle meningeal artery (MMA) is a major dural vessel that plays a significant role in developing chronic subdural hematomas (cSDHs). Understanding its variable anatomy is essential for the effective management of cSDH and the prevention of complications.

METHODS

MMA anatomy was retrospectively assessed in a population of 92 patients who underwent digital subtraction angiography of cerebral vessels before MMA embolization for cSDH.

RESULTS

We assessed 121 MMAs in 92 patients who underwent digital subtraction angiography for cSDH treatment from October 2020 to July 2023. The most common type in the extended Adachi classification was IC (19.82%) and the rarest was IB (6.31%). The anterior branch of the MMA was the most frequently dominant, while the most common origin of the posterior branch was observed in the distal segment. We reported 4 cases (3.31%) of the MMA arising from the ophthalmic artery.

CONCLUSIONS

The most common configuration of MMA was Adachi-type IC. The MMA most often originated from the maxillary artery. The posterior branch of the MMA was typically dominant and most frequently originated from the distal segment. There was no significant impact of Adachi type on treatment results or fluoroscopy time.

Nonopacification of Frontal and Parietal Branches After Middle Meningeal Artery Embolization: A Radiographic Benchmark

BACKGROUND

Middle meningeal artery embolization (MMAE) has revolutionized the armamentarium for chronic subdural hematoma (CSDH) treatment. Technical and angiographic benchmarks to guide procedural and clinical success are less well established.

METHODS

A single-center database was reviewed to compare outcomes after standalone MMAE with and without resultant residual angiographic opacification of frontal and parietal (F/P) branches. Primary outcome was surgical rescue for CSDH progression. Secondary outcomes included the efficiency and accumulated efficacy of hematoma resolution. Effect sizes were adjusted via multivariable regression.

RESULTS

Of 147 standalone MMAE for CSDH, the overall rate of surgical rescue was 6.8%. Nonopacification of F/P branches via proximal middle meningeal artery or meningo-ophthalmic anastomosis was achieved after 83% of procedures and was associated with a 7-fold decreased rate of surgical rescue (3.3% vs. 24%, P = 0.001). At 90-day follow-up, a higher rate of hematoma resolution ≥50% was achieved if no residual opacification was identified (82% vs. 56%, P = 0.03). The median time to 50% hematoma resolution was 44 days for the no-residual group versus 71 days for the residual group (P < 0.001). The unfavorable effects of residual opacification of F/P branches were verified in a multivariate analysis: a higher risk of surgical rescue (adjusted odds ratio 24.6; P = 0.001) and poor hematoma resolution were both confirmed (adjusted hazard ratio 0.3; P = 0.001).

CONCLUSIONS

MMAE with nonopacification of F/P branches was associated with augmented efficacy. Nuanced MMAE adequately tackling culprit dural feeders should be considered for more effective procedures.

Impact of Embolisate Penetration, Type, and Technique on Results After Standalone Middle Meningeal Artery Embolization for Chronic Subdural Hematoma

BACKGROUND AND OBJECTIVES

Middle meningeal artery embolization (MMAE) has emerged as a promising modality for chronic/subacute subdural hematoma treatment; however, consensus regarding embolization technique and embolisate has not been achieved. We thus sought to compare the efficacy of distinct MMAE techniques and embolisate.

METHODS

An institutional registry was reviewed to identify patients undergoing standalone MMAE for symptomatic chronic/subacute subdural hematoma. Surgical rescue rate and time preceding 50% hematoma resolution were evaluated across 3 technical groups: aggressive penetration (AP), nonaggressive penetration with proximal coil embolization (NP-PC), and nonaggressive penetration alone (NP). Effect sizes were adjusted for demographic, neurological and radiological features through multivariable logistic and Cox regression.

RESULTS

Among 117 procedures, 33.3% achieved AP, 36.8% had NP-PC, and 29.9% had NP. The rate of surgical rescue was 2.6% after AP, 9.3% for NP-PC, and 11.4% for NP. In patients not undergoing rescue surgery, 82.4% achieved hematoma resolution ≥50% at a median imaging follow-up of 56 days; AP or NP-PC were each statistically significantly associated with enhanced hematoma resolution as compared with NP ( P = .02). Similarly, sensitivity analysis within medium-size hematoma and antiplatelet/anticoagulation-at-admission subgroups revealed a superiority of resolution after AP or NP-PC. A unique, comparative secondary analysis of liquid embolisate (Onyx vs n-butyl cyanoacrylate) revealed no impact on rate of surgical rescue or hematoma resolution.

CONCLUSION

AP was associated with the lowest rate of surgical rescue, while both AP and NP-PC were associated with improved rates of hematoma resolution.

Frontal branch of the left middle meningeal artery arising from the ophthalmic artery diagnosed by magnetic resonance angiography

PURPOSE

A case of frontal branch of the left middle meningeal artery (MMA) arising from the ophthalmic artery (OA).

METHODS

A 73-year-old woman with vertigo underwent cranial magnetic resonance (MR) imaging and cranial MR angiography using a 1.5-Tesla scanner. MR angiography was performed using a standard 3-dimensional time-of-flight technique.

RESULTS

MR imaging revealed multiple small ischemic white matter lesions. Maximum-intensity-projection (MIP) MR angiography showed no pathological arterial lesions such as steno-occlusive lesions; however, the left MMA arose from the OA. On MR angiographic source images, the tiny left MMA passed through the foramen spinosum and supplied the parieto-occipital trunk of the MMA. Thus, the left MMA arising from the OA was considered the frontal branch. The right MMA normally supplies both the frontal branch and the parieto-occipital trunk.

CONCLUSION

We present a case of MMA originating from the OA. The prevalence of this variation has been reported to be approximately 0.5%, which is not very rare. However, most reported cases are diagnosed using catheter angiography or cadaver dissection. We diagnosed this variation using MR angiography. Careful observation of MR angiographic source images is useful and important for identifying tiny arteries that cannot be visualized using MIP MR angiography.

Organization of the Middle Meningeal Artery in a Sample of Black South African Population: Clinical Correlates

BACKGROUND

The middle meningeal artery (MMA) is the leading supplier of the cranial dura and serves as a donor blood channel in craniotomy and cerebrovascular bypass procedures. However, the complex embryology of the MMA and population differences give rise to several anatomic variations that are of great importance in head injuries pertaining to the petrous and squamous parts of the temporal bone. Similarly, care must be taken to protect the artery during surgical operations that involve the maxillary artery and the vidian nerve.

AIM

To evaluate the morphometry and clinical correlates of the middle meningeal artery in the black population of South Africa.

METHODS

The current study investigated the organization of the MMA in 100 adult dry human skulls (n = 50 males: n = 50 females) by tracing its grooves and measuring the length of the MMA, its frontal branch (FB), parietal branch (PB), the angle between FB and PB, and the angle of MMA from the foramen ovale (FO) bilaterally.

RESULTS

In comparison to females, males had significantly longer left PB (P = 0.003) and a considerably larger right angle of the MMA from the FO (P = 0.018). Furthermore, the PB was significantly longer on the left side than the right side in the entire sample (P = 0.002). Other parameters had no significant differences in sex and side.

CONCLUSIONS

The longer PB and the larger angle of the MMA in males could be attributed to why there is a high incidence of chronic subdural hematomas and MMA aneurysms in males. The current study is the first to propose a possible explanation for the aforementioned findings with regard to the organization of the MMA.

Penetration of Non-Adhesive Gel-like Embolic Materials During Dural Vessels Embolization According to Characteristics of Tantalum Powder

Tantalum powder is included in the composition of Non-Adhesive Gel-like Embolic Materials (NAGLEMs) for X-ray opacity. The duration of X-ray opacity during embolization is primarily associated with the particle size, which differs in the most used NAGLEMs-ONYX (Medtronic) and SQUID (Balt). NAGLEMs are widely used for the embolization of branches of the middle meningeal artery (MMA) in patients with chronic subdural hematomas (CSDHs). Considering the size (5-15 microns) of the target dural vessels, we assumed that not only the viscosity of NAGLEMs, but also the size and shape of tantalum granules may be important for the penetration of these gel-like embolic agents and determine their behavior. A notable discrepancy in size was observed. The medium-sized granules in the SQUID 18 sample (0.443 ± 0.086 microns, M ± SD) were found to be approximately ten times smaller than the tantalum granules in the ONYX 18 sample (5.2 ± 0.33 microns, M ± SD).Tantalum granules in SQUID 18 have a regular spherical shape; in ONYX 18 they have an irregular angular shape. When comparing the behavior of gel-like embolic agents of the same viscosity during MMA embolization in patients with CSDHs (an average age of 62.2 ± 14.3 years) in the group where SQUID 18 (n = 8) was used, the gel-like embolic agent in dural vessels demonstrated significantly greater penetration ability compared with the group where ONYX 18 (n = 8) was used. Accordingly, not only the viscosity of NAGLEMs, but also the size and shape of tantalum granules can have a significant effect on the penetration ability of gel compositions.

How I do it: operative nuances of the Encephalo-Duro-Mio-Synangiosis (EDMS) technique for pediatric moyamoya disease and syndrome

BACKGROUND

Moyamoya disease, a progressive occlusive arteriopathy mainly affecting the supraclinoid internal carotid artery, leads to abnormal "Moyamoya vessels" and ischemic events in children due to decreased cerebral blood flow. Surgery, especially indirect revascularization, is suggested for pediatric Moyamoya cases.

METHOD

We present the Encephalo-Duro-Mio-Synangiosis (EDMS) technique, illustrated with figures and videos, based on 14 years' experience performing 71 surgeries by the senior author (SGJ) and the Moyamoya Interdisciplinary Workteam at "Prof. Dr. J. P. Garrahan" Pediatric Hospital.

CONCLUSION

EDMS is a simple and effective treatment for Moyamoya disease, enhancing procedure precision and safety, reducing associated risks, complications, and improving clinical outcomes.

Advancements in super-selective catheterization and drug selection for intra-arterial chemotherapy for retinoblastoma: a 15-year evolution

BACKGROUND

Retinoblastoma (Rb) is the most common primary ocular malignancy of childhood. Left untreated, it is 100% fatal and carries a substantial risk of impaired vision and removal of one or both eyes. Intra-arterial chemotherapy (IAC) has become a pillar in the treatment paradigm for Rb that allows for better eye salvage and vision preservation without compromising survival. We describe the evolution of our technique over 15 years.

METHODS

A retrospective chart review was conducted of 571 patients (697 eyes) and 2391 successful IAC sessions over 15 years. This cohort was separated into three 5-year periods (P1, P2, P3) to assess trends in IAC catheterization technique, complications, and drug delivery.

RESULTS

From a total of 2402 attempted IAC sessions, there were 2391 successful IAC deliveries, consistent with a 99.5% success rate. The rate of successful super-selective catheterizations over the three periods ranged from 80% in P1 to 84.9% in P2 and 89.2% in P3. Catheterization-related complication rates were 0.7% in P1, 1.1% in P2, and 0.6% in P3. Chemotherapeutics used included combinations of melphalan, topotecan and carboplatin. The rate of patients receiving triple therapy among all groups was 128 (21%) in P1, 487 (41.9%) in P2, and 413 (66.7%) in P3.

CONCLUSIONS

The overall rate of successful catheterization and IAC started high and has improved over 15 years, and catheterization-related complications are rare. There has been a significant trend towards triple chemotherapy over time.

Traumatic middle meningeal artery aneurysm: a case report

INTRODUCTION

Traumatic intracranial aneurysms are rare, making up about 1% of all intracranial aneurysms. They can happen due to direct injury or blunt force, with the middle cerebral artery being the most frequent site. The middle meningeal artery (MMA) is the main artery that supplies the cranial dura mater, and, because of its location, is susceptible to damage after trauma. This article reported an unusual case of giant post-traumatic MMA pseudoaneurysm.

CASE

A 45 year-old man was referred to our department with a history of craniectomy. He complained of non-specific headache, but neurological examination was normal. A follow-up brain CT scan identified a right temporal fossa hyperdense mass. Digital subtraction angiography diagnosed a traumatic MMA aneurysm. The patient was treated with preoperative aneurysm embolization and surgical resection.

DISCUSSION

Traumatic MMA aneurysm is a rare presentation after head trauma. It can manifest as epidural hematoma, subdural hematoma or intraparenchymal hematoma, and sometimes resembles the present case, which was discovered incidentally.

CONCLUSION

Pseudoaneurysm is a rare complication of MMA trauma, with late presentation. It should be considered in patients with history of traumatic brain injury and temporal fossa extra-axial mass lesion with vascular characteristics.

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.

Middle meningeal artery arising from the petrous internal carotid artery: Outcome of unusual stapedial artery regression

Background

The internal and external carotid arterial systems are generally separate regarding branching patterns. However, these two systems do form collateral circulations with their terminal parts. On rare occasions, branches that belong to one arterial system may arise from the other.

Case Description

We present a rare variant of a middle meningeal artery, generally derived from the external carotid artery, arising from the internal carotid artery and entering the floor of the middle cranial fossa by traveling through a small unnamed foramen. This anatomy and embryology and other variants of the middle meningeal and petrous carotid systems are discussed.

Conclusion

Embryologically, this variant anatomy signifies an atypical regression of the distal stapedial artery and its connection to the external carotid artery. Surgeons who operate on the skull base, vascular interventionalists, and radiologists should be aware of this potential anatomical variation of the skull base.

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.

Middle Meningeal Artery Embolization for Refractory Chronic Subdural Hematoma Associated with Acute Myeloid Leukemia: A Case Report

Objective

We describe a patient with leukemia-related chronic subdural hematoma (CSDH) who was successfully treated using the combination of surgical evacuation and middle meningeal artery (MMA) embolization.

Case Presentation

A 73-year-old man without apparent head trauma history was admitted to our hospital because of acute myeloid leukemia (AML). Head CT on admission revealed mild CSDH on both sides. Medical treatment options, including chemotherapy, were started. Since a decrease in platelet count and disseminated intravascular coagulation were observed on day 4, recombinant thrombomodulin was administered. As the patient exhibited signs of altered consciousness due to the enlargement of the right CSDH on day 10, we performed surgical drainage. Despite subsequent platelet transfusion and administration of goreisan, the right CSDH recurred within a short period. On day 17, we performed the second surgery and MMA embolization in one stage. The postoperative clinical course was favorable without recurrence of the hematoma. The patient eventually died on day 123 from a deterioration of his general condition.

Conclusion

Although MMA embolization has recently been recognized as an effective treatment option for recurrent CSDH, there are no published reports addressing the efficacy of MMA embolization for refractory CSDH associated with hematological malignancies. Findings from the management of this case suggest that MMA embolization can be the effective treatment option for CSDH in patients with severe hemorrhagic diathesis due to AML.

Radiological evaluation of middle meningeal artery by 3D rotational angiography

PURPOSE

This study aimed to evaluate the topographic features and branches of the middle meningeal artery (MMA) by three-dimensional rotational angiography (3DRA) and describe its variations' radiological classification based on previous clinical examples of cadaver studies and literature.

METHODS

We consecutively evaluated 87 cerebral hemispheres, including 32 females and 49 right sides between May 2020 and December 2021 who had undergone unilateral or bilateral cerebral and carotid artery 3D rotational angiography imaging by CCA injection and between 18 and 76-years-old. Maximum intensity projection images with 10-30 mm slice thickness were used for the morphological evaluations and measurements of MMA and its foramen, canal, and branches.

RESULTS

The diameters of the common carotid artery, internal carotid artery, and external carotid artery were significantly smaller in females than in men (p = 0.021, 0.021, and <0.001, respectively). According to the branching pattern, the most common pattern of the MMA was Type Ia (49.4%). The ophthalmic artery completely originated from MMA in the 1 (1.1%) cerebral hemisphere. The MMA arises from the ophthalmic artery in 2 cerebral hemispheres (2.3%), and the ophthalmic artery and maxillary artery in 2 cerebral hemispheres (2.3%).

CONCLUSION

It was observed that the branching pattern may show differences when compared to the cadaver studies with a radiologic evaluation with 3D-RA.

Morphometric and morphologic analysis of the foramen spinosum in the Slovenian population with clinical correlations

Background

The foramen spinosum (FS) is a pivotal passage for neurovascular structures within the skull base. We performed a detailed morphometric and morphological analysis of the FS to emphasize its clinical relevance.

Materials & Methods

The study was performed on dried skull specimens obtained from the anatomical collections of the Institute of Anatomy and Institute of Forensic Medicine of the University of Ljubljana. The morphometric and morphologic features of FS in 126 whole human skulls and 15 skull halves were analyzed, including dimensions, shape, and other anatomical variations, as well as relationships to surrounding structures. Measurements were done with a digital sliding caliper.

Results

The mean length and width of the FS were 2.45 ± 0.65 mm and 2.03 ± 0.53 mm on the right side and 2.49 ± 0.61 mm and 2.08 ± 0.48 mm on the left side. The most frequently observed shape was round (56.7%), followed by oval (28.2%), irregular (8.7%) and drop shaped (6.3%). Several anatomical variations were also noted, including FS duplication, confluences with other foramina, and FS obstruction due to marginal bony outgrowths.

Conclusion

The FS exhibits notable interindividual differences in anatomical characteristics which should be considered during neurosurgical procedures and radiological interventions in the skull base.

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.

Predicting the progression of chronic subdural hematoma based on skull density

Objective

The objective of this study was to investigate potential correlations between skull density and the progression of chronic subdural hematoma (CSDH).

Methods

Patients with unilateral CSDH were retrospectively enrolled between January 2018 and December 2022. Demographic and clinical characteristics, as well as hematoma and skull density (Hounsfield unit, Hu), were collected and analyzed.

Results

The study enrolled 830 patients with unilateral CSDH until the resolution of the CDSH or progressed with surgical treatment. Of the total, 488 patients (58.80%) necessitated surgical treatment. The study identified a significant correlation between the progression of CSDH and three variables: minimum skull density (MiSD), maximum skull density (MaSD), and skull density difference (SDD) (p < 0.001). Additionally, in the multivariable regression analysis, MiSD, MaSD, and SDD were independent predictors of CSDH progression. The MiSD + SDD model exhibited an accuracy of 0.88, as determined by the area under the receiver operating characteristic curve, with a sensitivity of 0.77 and specificity of 0.88. The model's accuracy was validated through additional analysis.

Conclusion

The findings suggest a significant correlation between skull density and the CSDH progression.

Ischemia of the parotid gland and adjacent muscles of mastication following middle meningeal artery embolization

Middle meningeal artery (MMA) embolization is commonly performed as either a first-line or adjunct treatment for chronic subdural hematomas (cSDH). We present the case of a 59 year-old male patient who presented with right hemibody weakness and cognitive impairment and was diagnosed with left-sided cSDH. A left MMA embolization was performed due to the recurrent nature of the chronic subdural hemorrhage and the history of prior craniotomy. On postoperative day 1, the patient developed sudden onset left facial swelling and tenderness, and a contrast computed tomography (CT) of the neck revealed acute ischemia in the left parotid gland, adjacent superior aspect of the left masseter muscle, the left lateral pterygoid, and left temporalis muscles. The patient was treated conservatively with antibiotics, steroids, and analgesics and reported resolution of symptoms on the three-month follow-up. To our knowledge, this is the first reported case of the ipsilateral parotid gland, temporalis muscle, adjacent superior aspect of the masseter muscle, and pterygoid muscle ischemia secondary to non-target particle embolization following MMA embolization in cSDH. Knowledge of normal and variant origin of the MMA and various anastomoses of this vessel with branches of the internal carotid artery (ICA), external carotid artery (ECA), and vertebrobasilar system is crucial to avoid complications during embolization.

Excessive Postoperative Nasal Bleeding Following Septoplasty Caused by a Branch of the Middle Meningeal Artery

Septoplasty is a widely performed procedure globally to correct a deviated nasal septum and improve nasal breathing. Life-threatening nasal bleeding as a complication of septoplasty has been reported in a few cases in the literature. In cases of massive postoperative nasal bleeding, transarterial embolization using angiography was performed for the treatment. This article documents 1 case of excessive postoperative nasal bleeding following an uneventful septoplasty, which was successfully treated with embolization of the frontal branch of the middle meningeal artery. This case represents an extremely rare occurrence, and we present it in conjunction with a literature review.

Evaluation of an in vivo preclinical model for human middle meningeal artery embolization using the posterior intercostal artery of the swine

BACKGROUND

Embolization of the middle meningeal artery (MMA) is a promising minimally invasive technique that is gaining traction in the treatment of chronic subdural hematoma. Unfortunately, the human meninges and associated arteries are significantly larger than those of conventional laboratory animals, making the development of a clinically relevant animal model for testing of embolization agents elusive.

OBJECTIVE

To introduce the posterior intercostal artery (PIA) model in swine and provide anatomical, angiographic, histological, and procedural data to validate its relevance in modeling the human MMA.

METHODS

In human cadaveric specimens, 3D angiograms of the internal maxillary arteries (n=6) were obtained and the dura with MMA were harvested and histologically processed. Angiographic and histologic data of the human MMA were compared with the swine PIA (three animals). Then, embolization of the PIA (n=48 arteries) was conducted with liquid embolization agent (Onyx, Medtronic), and angiographic and histological results were assessed acutely (four animals) and after 30 days (two animals).

RESULTS

The human MMA has equivalent diameter, length, branching pattern, 3D trajectory, and wall structure to those of swine PIAs. Each swine has 12 to 14 PIAs (6-7 per side) suitable for acute or chronic embolization, which can be performed with high fidelity using the same devices, agents, and techniques currently used to embolize the MMA. The arterial wall structure and the acute and chronic histological findings in PIAs after embolization are comparable to those of humans.

CONCLUSIONS

This PIA model in swine could be used for research and development; objective benchmarking of agents, devices, and techniques; and in the training of neurointerventionalists.

Middle Meningeal Artery Embolization for Chronic Subdural Hematoma: Predictors of Clinical and Radiographic Failure from 636 Embolizations

Background Knowledge regarding predictors of clinical and radiographic failures of middle meningeal artery (MMA) embolization (MMAE) treatment for chronic subdural hematoma (CSDH) is limited. Purpose To identify predictors of MMAE treatment failure for CSDH. Materials and Methods In this retrospective study, consecutive patients who underwent MMAE for CSDH from February 2018 to April 2022 at 13 U.S. centers were included. Clinical failure was defined as hematoma reaccumulation and/or neurologic deterioration requiring rescue surgery. Radiographic failure was defined as a maximal hematoma thickness reduction less than 50% at last imaging (minimum 2 weeks of head CT follow-up). Multivariable logistic regression models were constructed to identify independent failure predictors, controlling for age, sex, concurrent surgical evacuation, midline shift, hematoma thickness, and pretreatment baseline antiplatelet and anticoagulation therapy. Results Overall, 530 patients (mean age, 71.9 years ± 12.8 [SD]; 386 men; 106 with bilateral lesions) underwent 636 MMAE procedures. At presentation, the median CSDH thickness was 15 mm and 31.3% (166 of 530) and 21.7% (115 of 530) of patients were receiving antiplatelet and anticoagulation medications, respectively. Clinical failure occurred in 36 of 530 patients (6.8%, over a median follow-up of 4.1 months) and radiographic failure occurred in 26.3% (137 of 522) of procedures. At multivariable analysis, independent predictors of clinical failure were pretreatment anticoagulation therapy (odds ratio [OR], 3.23; P = .007) and an MMA diameter less than 1.5 mm (OR, 2.52; P = .027), while liquid embolic agents were associated with nonfailure (OR, 0.32; P = .011). For radiographic failure, female sex (OR, 0.36; P = .001), concurrent surgical evacuation (OR, 0.43; P = .009), and a longer imaging follow-up time were associated with nonfailure. Conversely, MMA diameter less than 1.5 mm (OR, 1.7; P = .044), midline shift (OR, 1.1; P = .02), and superselective MMA catheterization (without targeting the main MMA trunk) (OR, 2; P = .029) were associated with radiographic failure. Sensitivity analyses retained these associations. Conclusion Multiple independent predictors of failure of MMAE treatment for chronic subdural hematomas were identified, with small diameter (<1.5 mm) being the only factor independently associated with both clinical and radiographic failures. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Chaudhary and Gemmete in this issue.

Subdural Hematomas in Adults and Children

Subdural hematoma is a common entity encountered by the neurosurgeon. The disease has acute, subacute, and chronic forms. Management of the disease changes according to the etiology of the lesion, yet the main goals are, as with most neurosurgical interventions, decompression of neural tissue and restoration of perfusion. Due to various forms and causes of the disease such as trauma, anticoagulant/antiaggregant use, arterial rupture, oncologic hemorrhages, intracranial hypotension, and idiopathic hemorrhages, several approaches for management have been documented in the literature. Herewith, we present various up-to-date management options for the disease.

Craniovascular variation in four late Holocene human samples from southern South America

Craniovascular traits in the endocranium (traces of middle meningeal vessels and dural venous sinuses, emissary foramina) provide evidence of vascular anatomy in osteological samples. We investigate the craniovascular variation in four South American samples and the effect of artificial cranial modifications (ACM). CT scans of human adult crania from four archeological samples from southern South America (including skulls with ACM) are used for the analyses. The craniovascular features in the four samples are described, skulls with and without ACM are compared, and additionally, South Americans are compared to a previously analyzed sample of Europeans. Of the four South American samples, the Southern Patagonian differs the most, showing the most distinct cranial dimensions, no ACM, and larger diameters of the emissary foramina. Unlike previous studies, we did not find any major differences in craniovascular features between modified and non-modified skulls, except that the skulls with ACM present somewhat smaller foramina. South Americans significantly differed from Europeans, especially in the anteroposterior dominance of the middle meningeal artery, in the pattern of sinus confluence, in the occurrence of enlarged occipito-marginal sinuses, and in foramina frequencies and diameters. Craniovascular morphology is not affected by the cranial size, even in skulls with ACM, indicating a minor or null influence of structural topological factors. Concerning the samples from distinct geographic and climatic environments, it must be evaluated whether the craniovascular morphogenesis might be partially influenced by specific functions possibly associated with thermoregulation, intracranial pressure, and the maintenance of intracranial homeostasis.

Anatomy and Physiology of Headache

Headache disorders can produce recurrent, incapacitating pain. Migraine and cluster headache are notable for their ability to produce significant disability. The anatomy and physiology of headache disorders is fundamental to evolving treatment approaches and research priorities. Key concepts in headache mechanisms include activation and sensitization of trigeminovascular, brainstem, thalamic, and hypothalamic neurons; modulation of cortical brain regions; and activation of descending pain circuits. This review will examine the relevant anatomy of the trigeminal, brainstem, subcortical, and cortical brain regions and concepts related to the pathophysiology of migraine and cluster headache disorders.

The "Bright Falx" Sign-Midline Embolic Penetration Is Associated With Faster Resolution of Chronic Subdural Hematoma After Middle Meningeal Artery Embolization: A Case Series

BACKGROUND

Chronic subdural hematomas (CSDHs) are common in the elderly population and patients taking antiplatelet/anticoagulation medications. Middle meningeal artery (MMA) embolization has become an adjunctive treatment to observation and surgery. Despite many embolization techniques, best practices for optimal CSDH resolution remain unknown.

OBJECTIVE

To report a retrospective case series of MMA embolization for CSDHs regarding rate of hematoma improvement and the significance of distal embolic penetration into the falx.

METHODS

Retrospective chart review was performed on all patients who underwent MMA embolization for CSDHs between January 2017 and June 2021. Patient demographics, clinical presentation, anticoagulant use, and radiographic features were collected. Pre-embolization and postembolization computed tomography scans were analyzed for volumetric changes and assessed for midline penetration of embolic material in the falx.

RESULTS

MMA embolization was performed in 37 patients and 53 hemispheres. Older patients took longer to obtain complete resolution of CSDHs (r = 0.47, P = .03). Patients with larger pre-embolization (r = 0.57, P = .007) and postembolization (r = 0.56, P = .008) CSDH volumes took longer to completely resolve. Patients who had n-butyl cyanoacrylate embolization with midline penetration, as evidenced by the "bright falx" sign, had faster improvement rates than those who did not (5.64 cm3/d vs 1.2 cm3/d, P = .02).

CONCLUSION

Distal penetration of embolic material, particularly n-butyl cyanoacrylate, into the falx may lead to more rapid improvement of CSDH.

Pharyngo-tympano-stapedial middle meningeal artery variant supply to a falcotentorial dural arteriovenous fistula

The pharyngo-tympano-stapedial middle meningeal artery (PTS-MMA) variant has been described in one case report and never in the setting of arterial supply to a dural arteriovenous fistula, to our knowledge. We report the case of a middle-aged patient with severe, daily headache who presented to our institution for angiography and treatment. CT angiography and MRI demonstrated an enlarged left middle meningeal artery coursing to a large venous varix in the falcotentorial region. Dural arteriovenous fistula was confirmed by subsequent cerebral angiography. Endovascular treatment was performed but without complete obliteration of the fistula. Follow-up angiography demonstrated parasitized arterial supply from a right middle meningeal artery arising from the proximal cervical internal carotid artery coursing through the middle ear consistent with a PTS-MMA variant. The fistula was then treated surgically without recurrence at the 6-month follow-up.

Dural Immune Cells, CGRP, and Migraine

Migraine is the most common neurological disorder in the world, affecting 12% of the population. Migraine involves the central nervous system, trigeminal nerves and meninges. Recent advances have shown that targeting calcitonin gene-related peptide (CGRP) through either antibodies or small molecule receptor antagonists is effective at reducing episodic and chronic migraine episodes, but these therapeutics are not effective in all patients. This suggests that migraine does not have a singular molecular cause but is likely due to dysregulated physiology of multiple mechanisms. An often-overlooked part of migraine is the potential involvement of the immune system. Clinical studies have shown that migraine patients may have dysregulation in their immune system, with abnormal plasma cytokine levels either during the attack or at baseline. In addition, those who are immunocompromised appear to be at a higher risk of migraine-like disorders. A recent study showed that migraine caused changes to transcription of immune genes in the blood, even following treatment with sumatriptan. The dura mater is densely packed with macrophages, mast and dendritic cells, and they have been found to associate with meningeal blood vessels and trigeminal afferent endings. Recent work in mice shows activation and morphological changes of these cells in rodents following the migraine trigger cortical spreading depression. Importantly, each of these immune cell types can respond directly to CGRP. Since immune cells make up a large portion of the dura, have functional responses to CGRP, and interact with trigeminal afferents, CGRP actions on the dural immune system are likely to play key roles in migraine.

Brain Vascular Microenvironments in Cancer Metastasis

Primary tumours, particularly from major solid organs, are able to disseminate into the blood and lymphatic system and spread to distant sites. These secondary metastases to other major organs are the most lethal aspect of cancer, accounting for the majority of cancer deaths. The brain is a frequent site of metastasis, and brain metastases are often fatal due to the critical role of the nervous system and the limited options for treatment, including surgery. This creates a need to further understand the complex cell and molecular biology associated with the establishment of brain metastasis, including the changes to the environment of the brain to enable the arrival and growth of tumour cells. Local changes in the vascular network, immune system and stromal components all have the potential to recruit and foster metastatic tumour cells. This review summarises our current understanding of brain vascular microenvironments, fluid circulation and drainage in the context of brain metastases, as well as commenting on current cutting-edge experimental approaches used to investigate changes in vascular environments and alterations in specialised subsets of blood and lymphatic vessel cells during cancer spread to the brain.

Characterization of the pterygomeningeal artery based on branching pattern and muscular distribution

PURPOSE

The pterygomeningeal (accessory meningeal) artery arises from the middle meningeal or maxillary artery. Although there is the potential that this artery may be wounded by the surgery for the temporomandibular joint disorder, the current state of anatomical knowledge is insufficient. This study investigated the appearance and the branching pattern of this artery as a means to its characterization.

METHODS

The pterygomeningeal artery was dissected in 14 cadavers and its branches and their distributions to the muscles inside the mandible were examined.

RESULTS

The maxillary artery passed lateral to the lateral pterygoid muscle. The pterygomeningeal artery arose from the middle meningeal or maxillary artery. It ascended anteriorly and coursed medial or lateral to the mandibular nerve. It passed above the pterygospinous ligament and then descended. The ascending trunk gave some lateral branches to the lateral pterygoid muscle. The branches sometimes passed lateral to the mandibular nerve even if the pterygomeningeal artery coursed medial. The descending trunk was divided into middle and medial branches, which supplied the medial pterygoid muscle and the tensor veli palatini, respectively. The pterygomeningeal artery was sometimes equally bifurcate near the origin, and the counterparts passed lateral and medial to the mandibular nerve. The distributions of the medial and lateral counterparts were equivalent to those of the descending trunk and the lateral branches, respectively.

CONCLUSION

The pterygomeningeal artery contains three groups of muscular branches, which sometimes appear in a bifurcate form. Their positions relative to the mandibular nerve and the pterygospinous ligament characterize the artery; this information may help to avoid iatrogenic injury.

The Middle Meningeal Artery: Branches, Dangerous Anastomoses, and Implications in Neurosurgery and Neuroendovascular Surgery

The middle meningeal artery (MMA) has always been the workhorse corridor for devascularization of dural-based intracranial lesions and, more recently, has been established as a target for the endovascular management of chronic subdural hematomas. The MMA anatomy is complex and deceitful, and its territory of irrigation (including cranial nerves) is poorly understood. Furthermore, MMA variations and anastomoses are more frequent than expected, which may predispose to procedure-related morbidity. A literature search was conducted in electronic databases per PRISMA guidelines for studies describing normal and abnormal MMA anatomy including variations in MMA origin and dangerous anastomoses. Our institutional case series of greater than 100 MMA embolizations for management of chronic subdural hematomas were reviewed for abnormal MMA anatomy, and clinically relevant case examples are presented. In this article, we provide a comprehensive review of the MMA to provide a better understanding and appreciation of this artery, including pearls and pitfalls, that we hope will aid the neurosurgeon and neurointerventionalist in safely tackling these lesions.

Dilated MMA sign in cDAVF and other arterial feeders on 3D TOF MRA

Background

Among the varied causes of pulsatile tinnitus, the condition that can cause severe mortality and morbidity is a cranial dural arteriovenous fistula (cDAVF). This study aimed to assess the diagnostic accuracy of the dilated middle meningeal artery on three-dimensional time-of-flight magnetic resonance angiography in cranial dural arteriovenous fistula and to identify other feeders that can aid in the detection of these lesions.

Method

Magnetic resonance angiography and digital subtraction angiography data of all patients with cranial dural arteriovenous fistula treated in a single tertiary referral center between 2007–2020 were included. The middle meningeal artery and other feeders recorded from digital subtraction angiography were assessed on magnetic resonance angiography.

Results

The overall agreement between readers in identifying the dilated middle meningeal artery was substantial (κ = 0.878, 95% confidence interval: 0.775–0.982). The dilated middle meningeal artery indicated the presence of a cranial dural arteriovenous fistula with a sensitivity of 79.49% (95% confidence interval: 66.81–92.16), specificity of 100% (95% confidence interval: 100.00–100.00), and negative predictive value of 94.56% (95% confidence interval: 90.89–98.02). An area under the curve of 0.8341 was observed for the ipsilateral middle meningeal artery, with a sensitivity of 92.2% and a specificity of 75.0% at a cut-off of 0.30 mm for identifying a cranial dural arteriovenous fistula. Of 73 other feeders, the occipital, meningohypophyseal trunk, ascending pharyngeal, and posterior meningeal arteries contributed to a large proportion visualized on magnetic resonance angiography (83.6% (41/49)).

Conclusion

The dilated middle meningeal artery sign is useful for identifying a cranial dural arteriovenous fistula. Dilatation of the occipital and ascending pharyngeal arteries and meningohypophyseal trunk should be assessed to facilitate the detection of a cranial dural arteriovenous fistula, particularly in the transverse-sigmoid and petrous regions.

Intra-arterial injection of lidocaine into middle meningeal artery to treat intractable headaches and severe migraine

BACKGROUND AND PURPOSE

We report the results of intra-arterial injection of lidocaine in the middle meningeal artery in patients with intractable headache or status migrainosus.

METHODS

We treated four patients with intra-arterial lidocaine (2 mg/ml) in doses up to 50 mg in each middle meningeal artery via a microcatheter bilaterally (except in one patient). In two patients with intractable headache, the daily maximum intensity of headache (graded by 11-point numeric rating scale) was recorded for 7 days postprocedure. In two patients with status migrainosus, migraine-related disability 3 months prior and after treatment using MIDAS (Migraine Disability Assessment) questionnaire was recorded.

RESULTS

Intra-arterial lidocaine reduced the headache intensity from 8/10 and 10/10 to 0/10 in the two patients with intractable headaches for 2 days (day 0 and day 1) postprocedure. Despite recurrence of headache on day 2, the intensity was less than preprocedure intensity up to the last day recorded (by 3 and 2 points on day 7). In the two patients with status migrainosus, there was immediate reduction in headache intensity following intra-arterial lidocaine. The post treatment 3-month MIDAS score was lower in both patients compared with pretreatment 3-month score; 3 versus 30 and 55 versus 90. Severe disability preprocedure by MIDAS was reduced to little or no disability postprocedure in one patient.

CONCLUSIONS

Intra-arterial lidocaine resulted in amelioration of headache in patients with intractable headache and those with status migrainosus with improvement lasting longer than the short half-life of lidocaine possibly related to central desensitization.

Neuroanatomy of cranial dural vessels: implications for subdural hematoma embolization

Adoption of middle meningeal artery embolization in the management of chronic subdural hematomas has led to a renewed interest in dural vascular anatomy. The readily identifiable major dural arteries and potential hazards associated with their embolization are well described. Less emphasized are several levels of intrinsic dural angioarchitecture, despite their more direct relationship to dural based diseases, such as subdural hematoma and dural fistula. Fortunately, microvascular aspects of dural anatomy, previously limited to ex vivo investigations, are becoming increasingly accessible to in vivo visualization, setting the stage for synthesis of the old and the new, and providing a rationale for the endovascular approach to subdural collections in particular. In contrast with traditional anatomical didactics, where descriptions advance from larger trunks to smaller pedicles, we present a strategic approach that proceeds from a fundamental understanding of the dural microvasculature and its relationship to larger vessels.

Sphenoidal artery: review of the literature and analysis of a dissected arterially injected fetal orbit

PURPOSE

The sphenoidal artery is considered a component of the complex and dangerous arterial anastomoses of the human orbitocranial region, particularly with the advent of interventional neuroimaging. The objective of this publication was to analyze the various descriptions of the sphenoidal artery in the literature as related to relevant photographs of a dissected arterially injected fetal middle cranial fossa and orbit.

METHODS

Publications dealing with middle meningeal-ophthalmic arterial anastomoses, focusing on the sphenoidal artery, were reviewed. A relevant dissection of a fetal specimen was analyzed.

RESULTS

The literature dealing with the sphenoidal artery is at times not in agreement. The nomenclature and anatomy of its passage through the superior orbital fissure or Hyrtl canal have variable descriptions. Photographs of the skull base of a dissected arterially injected fetal specimen show bilateral prominent orbital branches of the middle meningeal arteries. These branches entered both orbits in a course similar to the diagrammatic representations of the sphenoidal artery, and give rise to several major intraorbital arteries. This study provides the only photographic image in the literature of this variation in a human fetal anatomic dissection.

CONCLUSIONS

Review of the literature dealing with the sphenoidal artery shows inconsistent nomenclature and conflicting descriptions of its anastomotic connections, and varying evolutionary and embryologic theories. Analysis of the dissected fetal skull base indicates that the sphenoidal artery is not a distinct artery but just a middle meningeal orbital arterial branch, an important component of the complex and dangerous arterial anastomoses of the human orbitocranial region.

Anatomic and Embryologic Analysis of the Dural Branches of the Ophthalmic Artery

The ophthalmic artery has one of the most fascinating embryologic developments among the craniofacial arteries. Most of the ophthalmic artery orbital branches develop from the formation and regression of the stapedial artery and share their origin with dural branches of the ophthalmic artery. The concomitant embryologic development of the ophthalmic artery and middle meningeal artery explains adequately the important varieties of anastomosis between these 2 arteries. It also explains the presence of many dural branches from the ophthalmic artery. In this review, we focused on dural branches of the ophthalmic artery with the description of rare variations possible, in particular the ophthalmic artery origin of the middle meningeal artery and the ophthalmic artery origin of the marginal tentorial artery.