Dural arteriovenous fistulas in the falx cerebri: case series and literature review.

Dural arteriovenous fistulas (DAVFs) within the falx cerebri are infrequently documented and may be linked with the falcine sinus/venous plexus. The falcine sinus/venous plexus, often regarded as a normal venous structure, can exhibit pathological characteristics, differing from the persistent fetal falcine sinus. A retrospective analysis was conducted at a single center to identify all cases of DAVFs within the falx cerebri spanning from 2002 to 2022. Demographic data, fistula features, treatment modalities, clinical outcomes, and fistula closure were collected and analyzed. Additionally, relevant literature on DAVFs in this location was reviewed. Ten cases were identified at our center, supplemented by 13 cases reported in the literature. In our cohort, patients had an average age of 49.4 ± 8.1 years, with a male predominance of 90%. Trans-arterial embolization (TAE) alone achieved immediate complete occlusion in eight cases, while conservative treatment was pursued in two cases. No treatment-related complications or fistula recurrences were observed. In the literature, seven patients underwent direct surgery, three underwent TAE, and one underwent both direct surgery and radiosurgery for complete fistula closure. No instances of fistula recurrence or treatment complications were reported. Dural arteriovenous fistulas within the falx cerebri are rare, with limited literature available. They typically present as aggressive lesions. Treatment options include direct surgery or TAE. However, due to a lack of long-term DSA follow-up, the cure and recurrence rates are unknown for endovasdcular therapy. Further investigation is warranted to elucidate the involvement of the falcine sinus/venous plexus in falx cerebri DAVFs.

Utility of susceptibility weighted imaging (SWI) and pseudo-continuous arterial spin labeling (pCASL) in diagnosis of falcine venous thrombosis in a child with transient ischemic attack.

Pediatric stroke and transient ischemic attack (TIA) are uncommon but true emergencies with a wide differential diagnosis. Diagnostic imaging plays a critical role in differentiating the diverse range of etiologies. In this case, we report a 3-year-old female with no medical history who developed acute neurological deficits and demonstrate how adjunct advanced imaging including susceptibility weighted imaging (SWI) and pseudo-continuous arterial spin labeling (pCASL) can play a significant diagnostic role in the emergent setting. Imaging was performed with a Philips Ingenia 3.0T MRI. MRI brain, MR angiography (MRA), and phase contrast angiography MR Venography (PCA-MRV) were obtained. pCASL and SWI sequences were performed using SENSE (sensitivity encoding) parallel imaging techniques. MRI/MRA brain showed no restricted diffusion, abnormal T1/T2/FLAIR signal, arterial occlusion, or irregular angioarchitecture. SWI revealed increased susceptibility along the posterior falx cerebri and right posterior parietal and occipital lobes, and pCASL showed decreased blood flow within these same regions. No falcine sinus was visualized on PCA-MRV, but SWI and pCASL findings led to diagnosis of falcine sinus thrombosis and initiation of appropriate treatment. Repeat MRI one month later showed interval resolution of the abnormal SWI findings and a now patent persistent falcine sinus visualized on PCA-MRV imaging. Routine use of SWI imaging on all brain MRIs and addition of pCASL imaging when there is concern for ischemia or infarction in the emergent setting can limit the risk of missed occult diagnoses like a thrombosed falcine sinus.

Chiari I malformation with craniosynostosis and persistent falcine sinus draining into the straight sinus.

Owing to the interconnected nature of the brain, anatomical variations in one area often coincide with, or are caused by, abnormalities in another. During dissection of a specimen with both Chiari I malformation and craniosynostosis, a persistent falcine sinus was observed to drain into the straight sinus. Such a variant should be noted by physicians as it could alter treatment plans and require more detailed imaging procedures prior to surgical correction. Herein, we report the case and discuss the possible embryological origins and clinical significance of the variant.

Persistent falcine sinus with temporo-occipital schizencephaly: case report with a review of literature in relation to the undeveloped vein of Galen and/or straight sinus.

Falcine sinus is a normal midline embryonic venous sinus present in the fetal brain and usually disappears by birth. Persistent falcine sinus (PFS) has been reported as a normal variant or along with vein of Galen (VOG) malformation, encephalocele, and other abnormalities. Schizencephaly, either closed or open type, has been reported with other associated vascular anomalies. We report a 22-month-old child, who presented with delayed milestones and referred for magnetic resonance (MR) imaging, and the child was found to have PFS with associated bilateral temporo-occipital closed-lip schizencephaly, hippocampal abnormalities, falco-tentorial dehiscence, and white matter abnormalities. The vein of Galen and straight sinus were absent, and the internal cerebral veins were seen draining into superior sagittal sinus via the falcine sinus. These set of abnormalities are unique from abnormalities reported previously in association with the falcine sinus.

The Impact of Angiographic Geometry on the Clinical Presentation of True Vein of Galen Aneurysmal Malformations.

BACKGROUND PURPOSE: Vein of Galen aneurysmal malformations (VGAM) may carry life-threatening and catastrophic sequelae in children. Their clinical presentations are differently variable between cardiac and cerebral syndromes. There may be a possible relationship between the Galenic angioarchitecture and the clinical presentation. We aimed to study the effect of the venous outflow impairment on the incidence of high-flow heart failure and the incidence of hydrocephalus. MATERIALS AND METHODS: The angiographies of 21 patients with true VGAM have been studied. MR angiography, 3-dimensional CT angiogram (3D CTA), and conventional digital subtraction angiography were performed for all patients with true VGAM. Transarterial embolization was done in 1 or more sessions for all cases. RESULTS: Among the 21 cases, 14 cases were mural type, 5 cases were choroidal type, and 2 cases were mixed. Hydrocephalus was observed more in infants (92.3%), mural types (92.9%), giant and supergiant (87.5%) aneurysms, and in cases with persistent limbic circle (90.91%). All cases of hydrocephalus were associated with significant stenosis (>70%) of the Falcine sinus draining system (100%). CONCLUSION: Significant stenosis (>70%) of the draining sinus is a significant factor for VGAM aneurysmal enlargement and occurrence of hydrocephalus. Probably, venous outflow impairment decreases the incidence of high-flow heart failure and increases the incidence of hydrocephalus.

Dural Sinus Thrombosis with Nonsymptomatic Persistent Falcine Sinus: A Case Report.

A 24-year-old woman was admitted to our hospital after convulsive status epilepticus. A cerebral magnetic resonance venography revealed a persistent fetal falcine sinus. Additionally, the posterior third of the superior sagittal sinus was hypoplastic and the abnormal deep venous drainage was accompanied. These abnormalities had already been detected by magnetic resonance imaging several years ago. In the present scan, we discovered a sinus thrombosis in the hypoplastic superior sagittal sinus. In the cerebral angiography, we observed delayed venous return in the left parieto-occipital lobe and hypothesized that cerebral venous stasis due to the thrombus caused the convulsive status epilepticus. The patient was treated with intravenous administration of heparin along with an antiepileptic drug, and she recovered with no neurological defects. In the present case, the falcine sinus and the anomalous venous return were likely congenital while the status epilepticus was derived from thrombosis in the hypoplastic superior sagittal sinus. Although the falcine sinus functioned as an alternative pathway for the superior sagittal sinus, the hypoplastic superior sagittal sinus itself may also play an important role as a venous drainage channel.

Venous channels of the falx cerebri in adult Japanese population: delineation using magnetic resonance imaging.

PURPOSE: Few studies have characterized the venous channels of the falx cerebri under physiological conditions. The present study aimed to explore the falx cerebri using magnetic resonance imaging (MRI). METHODS: A total of 91 patients (41 men and 50 women) with an intact falx cerebri and relevant dural sinuses underwent contrast MRI. RESULTS: In 15% of the participants, the falx cerebri contained venous channels with a patchy appearance. Seven of these channels were located in the anterior third of the falx, two were in the anterior two-thirds, and 5 were in the middle third. In 19 (21%) participants, the falcine sinus was unequivocally delineated. In 14 of them, connected the posterior third of the superior sagittal sinus and uppermost part of the straight sinus. These sinuses showed variable morphologies, presenting with linear, triangular, multi-channel, and branching appearances. The linear type was the most predominant and found in 50% of these cases. In contrast, in the remaining five participants, the falcine sinuses were coursing posteriorly, connecting the posterior third of the falx cerebri with the superior sagittal sinus. CONCLUSION: The falx cerebri may have a role as a pathway in the intracranial venous circulation. The falcine sinus has several variants with diverse morphologies.

Fate of the three embryonic dural sinuses in infants: the primitive tentorial sinus, occipital sinus, and falcine sinus.

PURPOSE: The primitive tentorial, occipital, and falcine sinuses are thought to attain the adult pattern or regress between the fetal stage and adulthood. The anatomy of these three primitive dural sinuses has seldom been studied in the infant population, and it remains unclear when these dural sinuses reach the adult condition. Using computed tomography digital subtraction venography (CT-DSV), we analyzed the anatomy of these embryonic dural sinuses in infants. METHODS: We included 13 infants who underwent CT-DSV prior to neurosurgery and 35 cases with unruptured cerebral aneurysms as normal adult controls. Three embryonic dural sinuses, i.e., the primitive tentorial, occipital, and falcine sinuses, were retrospectively analyzed in CT-DSV images of infants and adults. We also analyzed the drainage patterns of the superficial middle cerebral vein (SMCV), determined by the connection between the primitive tentorial sinus and the cavernous sinus. RESULTS: The primitive tentorial, occipital, and falcine sinuses were present in 15.4%, 46.2%, and none of the infants, respectively, and in 10.0, 8.6, and 2.9% of the adults, respectively. The difference in SMCV draining pattern between infants and adults was insignificant. The incidence of the occipital sinus was significantly higher in infants than in adults. CONCLUSIONS: The connection between the primitive tentorial sinus and the cavernous sinus appears to be established before birth. The occipital sinus is formed at the embryonic stage and mostly regresses after infancy. The falcine sinus is usually obliterated prenatally. Our findings form the basis for interventions by pediatric interventional neuroradiologists and neurosurgeons.

A review of extraaxial developmental venous anomalies of the brain involving dural venous flow or sinuses: persistent embryonic sinuses, sinus pericranii, venous varices or aneurysmal malformations, and enlarged emissary veins.

This paper is a narrative review of extraaxial developmental venous anomalies (eDVAs) of the brain involving dural venous flow or sinuses: persistent embryonic sinuses, sinus pericranii, enlarged emissary veins, and venous varices or aneurysmal malformations. The article highlights the natural history, anatomy, embryology, imaging, clinical implications, and neurosurgical significance of these lesions, which the authors believe represent a continuum, with different entities characterized by distinct embryopathologic features. The indications and surgical management options are discussed for these individual intracranial pathologies with relevant illustrations, and a novel classification is proposed for persistent falcine sinus (PFS). The role of neurointervention and/or microsurgery in specific cases such as sinus pericranii and enlarged emissary veins of the skull is highlighted. A better understanding of the pathophysiology and developmental anatomy of these lesions can reduce treatment morbidity and mortality. Some patients, including those with vein of Galen malformations (VOGMs), can present with the added systemic morbidity of a high-output cardiac failure. Although VOGM is the most studied and classified of the above-mentioned eDVAs, the authors believe that grouping the former with the other venous anomalies/abnormalities listed above would enable the clinician to convey the exact morphophysiological configuration of these lesions, predict their natural history with respect to evolving venous hypertension or stroke, and extrapolate invaluable insights from VOGM treatment to the treatment of other eDVAs. In recent years, many of these symptomatic venous malformations have been treated with endovascular interventions, although these techniques are still being refined. The authors highlight the broad concept of eDVAs and hope that this work will serve as a basis for future studies investigating the role of evolving focal venous hypertension/global intracranial hypertension and possibilities of fetal surgical intervention in these cases.

Venous anomaly analogous to vertical embryonic positioning of the straight sinus associated with atretic cephalocele at the suboccipital region.

BACKGROUND: The coexistence of venous anomalies, such as vertical embryonic positioning of the straight sinus (VEP of SS), has been reported in patients with atretic cephalocele (AC). VEP of SS has been exclusively encountered when the AC is found above the torcular. CLINICAL PRESENTATION: We report a patient with suboccipital AC associated with venous anomalies analogous to VEP of SS, consisted of the Galenic venous system which did not drain into the straight sinus in the tentorium, but into the falcine sinus instead. Differences with VEP of SS in our case had no anatomical relationship between the falcine sinus and the suboccipital AC and no large cerebrospinal fluid space around the falcine sinus. A detailed neuroradiological examination was helpful for detecting these minute anomalies.

Tadpole-shaped lateralized parietal atretic cephalocele associated with an ipsilateral lacrimal gland fistula and schizencephalic clefts.

BACKGROUND: Parietal atretic cephalocele (AC) and its associated intracranial venous anomalies, such as vertical embryonic positioning of the straight sinus (VEP of SS), have, in previous reports, been exclusively restricted to the midline. CLINICAL PRESENTATION: We report a patient with lateralized parietal AC on the right side. The AC was in the shape of a tadpole, with a large head and a long tail, extending to the proximity of the right external canthus, where a lacrimal gland fistula was observed. The superior sagittal sinus and VEP of SS were also displaced to the right side, although the sagittal suture was located at the midline. Schizencephalic clefts in the right posterior cortex were also observed. CONCLUSION: The parietal AC, which was initially located in the midline, could conceivably have been displaced to the right side by other developmental processes. However, the relationship between lateralized AC and associated multiple anomalies on the ipsilateral side is difficult to explain monogenetically. Our case study indicates that AC might have a broader spectrum of clinical symptoms than was once thought to be the case.

Anatomy of the falcine sinus during the prenatal period.

BACKGROUND: The falcine sinus in the falx cerebri is rarely encountered in adults, appearings in approximately 2.1% of CT examinations of adult patients. Some authors have studied the plexus rather than the sinus, a rare form of the venous pathway between the layers of the cerebral falx, which connects the superior sagittal sinus with the inferior sagittal sinus and the straight sinus. The aim of this study was to analyse the anatomy of the falcine sinus in the prenatal period, which will fill a gap in the literature. MATERIALS AND METHODS: This study consisted of 50 foetuses with a v-tube length of 89-229 mm and the equivalent of 15-28 weeks of intrauterine development on the Scammon and Calkins scale. METHOD: Blood vessels were filled with latex LBS 3022, and analysis was performed using the Scion Image for Windows 4.0.3.2 and Image J. We used various linear and nonlinear transformations. RESULTS: In 20 cases, intraventricular and periventricular haemorrhages were detected. The other cases showed sinuses in the cerebral falx, specifically in the back parts of the falx, and were described as oblique, straight, wavy, or network. A very rich venous network is located around the superior sagittal sinus; the middle section grew twice its length and the back section grew three times its width, reaching the lowest areas of the cerebral falx, the inferior sagittal sinus, and the straight sinus. Anastomotic intersinual loops appeared. There were three forms of venous weave crescents: isolated limited to the area adjacent to the superior sagittal sinus, partly merging with the straight sinus and a fully developed falcine sinus, which appeared in the older age groups with the most primitive forms being plexiform. Their remains a plurality of channels within the same superior sagittal sinus that show a predominance in the posterior segment. CONCLUSION: The location of the falcine sinus has been mostly associated with the rear one-third of the cerebral falx and should be considered during neurosurgery, because the front two-thirds of the cerebral falx are called the "safe zone". Knowledge of the falcine sinus anatomy is important for descriptions in neuroimaging examinations.

Prevalence of persistent falcine sinus as an incidental finding in the pediatric population.

OBJECTIVE: Persistence of the embryologic falcine sinus can be a congenital or acquired phenomenon related to a defect of the straight sinus. Previous studies have stated that it is rare for the falcine sinus to persist without an additional abnormality of the brain such as a vein of Galen malformation or venous sinus thrombosis. The purpose of this article is to show that persistent falcine sinus is not an uncommon isolated finding in the pediatric population. MATERIALS AND METHODS: We performed a retrospective review of pediatric brain MRIs to identify patients with a persistent falcine sinus and subsequently recorded whether there were findings in addition to the straight sinus defect. RESULTS: Thirty-one patients were identified as having a persistent falcine sinus, five of whom had no other congenital or acquired abnormality of the brain other than a defect in the straight sinus. CONCLUSION: Our data support the hypothesis that persistent falcine sinus is not an uncommon isolated finding in the pediatric population.

Large parietal midline defect with unusual ridge-like structure at the rim and persistent falcine sinus.

BACKGROUND: Midline cranial defects can be divided into lesions with intracranial tissue herniation (cranium bifidum cysticum) and lesions mainly with ossification failure (cranium bifidum occultum). Herniated cephaloceles mostly require surgical resection, while persisted parietal foramina might become smaller with age. CLINICAL CASE: Here, we report a neonate with large symmetric midline skull defect at high parietal area. A mild bulging mass was noticed. Interestingly, unlike sac herniation, it was surrounded by bony ridges extended from the rim of the calvarial defect, which suggests aberrant ossification. Persistent falcine sinus was also detected. At the corrected age of 11 months, the size of the skull defect had decreased spontaneously, favoring the diagnosis of parietal bone ossification defect. Potential mechanisms resulting in the special appearance of skull bone were discussed. CONCLUSION: Incomplete closing of the parietal foramina might be expected due to the aberrant ridge formation. We suggest protective measures for the calvarial defect.

Persistent falcine sinus in the newborn: 3 case reports of associated anomalies.

The falcine sinus is a normal embryonic structure that is situated between the 2 layers of the falx cerebri and drains the deep cerebral venous system into the superior sagittal sinus. It normally involutes after birth and is uncommon in adults. Although it is often an isolated and incidental finding, it can also be associated with a number of other conditions including but not limited to vein of Galen arterial malformations (VGAM), atretic parietal cephaloceles, acrocephalosyndactyly (Apert syndrome), absence of the corpus callosum, absence of the tentorium, osteogenesis imperfecta, or Chiari II malformations. We present a case series of 3 pediatric patients born with a persistent falcine sinus and an associated condition, including a VGAM, an APC, and a sinus thrombosis. The purpose of this article is to highlight the importance of understanding anatomic variations in the cerebral venous system to help aid in the proper diagnosis and treatment of associated pathologies.

Endovascular Management of Falcine Dural Arteriovenous Fistula-A Case Report and Review of Literature.

Cranial dural arteriovenous (AV) fistulas are abnormal connections between the branches of dural arteries to dural veins or venous sinuses. They are most frequently located at the transverse sinus and cavernous sinus. They can occur at every cranial dural sinus. Dural AV fistula of falx cerebri is rare. A 62-year-old female presented with signs and symptoms of raised intracranial pressure. Radiological imaging revealed a dural AV fistula at the posterior one-third falx cerebri. She underwent transarterial embolization, and complete obliteration of the fistula was achieved. A detailed digital subtraction angiography study is warranted in patients with seemingly benign complaints like recurrent headaches, and falcine dural AV fistula should be identified and treated in the nick of time. We describe a very rare falcine dural AV fistula case and its management.

Atretic cephaloceles with different imaging phenotypes - Case series with review of literature.

Atretic cephaloceles (ACs) are congenital skull defects with herniation of rudimentary intracranial structures through the defect and associated with persistent falcine sinus or embryonic positioning of straight sinus. We describe five cases of ACs, out of which only one had embryonic straight sinus. Three cases had other intracranial malformations such as hypoplasia of corpus callosum, dysplastic tectum in one child and parieto-occipital polymicrogyria with falcotentorial dehiscence in the other, and frontal horn deformity and cortical dysplasia in the third. The prognosis of AC depends on the coexistent intracranial abnormalities and this highlights the role of magnetic resonance imaging in diagnosing the other associated anomalies for prediction of prognosis and planning of necessary surgical management.

A case of traumatic acute interhemispheric subdural hematoma due to injured dural branch of anterior cerebral artery.

Background: The precise causes of traumatic acute interhemispheric subdural hematoma (AISDH) are unclear in most cases, and there are few cases, where the sources of bleeding are directly confirmed intraoperatively. We report a rare case of traumatic AISDH, in which a damaged dural branch of anterior cerebral artery (ACA) to the cerebral falx was identified as the cause of bleeding during hematoma removal. Case Description: A 61-year-old man with a history of craniotomy for the left putaminal hemorrhage at the age of 50 fell from a bed, bruised his head, and lost consciousness. Computed tomography of the head showed AISDH of 2.5cm in thickness, which was removed through a parietal parasagittal craniotomy under the microscope. Intraoperatively, the bleeding source was revealed to be a damaged dural branch from ACA to the cerebral falx. There was no rebleeding during his stay in our hospital. Conclusion: In this case, intraoperative findings revealed that the cause of bleeding was a damage to the dural branch of ACA. A vascular study is mandatory to rule out a vascular malformation in similar cases.

Parietal Encephalocele With Fenestrated Superior Sagittal Sinus and Persistent Falcine Sinus.

We present a case of a newborn with a fenestrated superior sagittal sinus and persistent falcine sinus with a parietal encephalocele. The patient was born full-term without any associated pregnancy complications other than meconium-stained amniotic fluid at delivery. Following delivery, MRI brain demonstrated midline parietal encephalocele, persistent falcine sinus, fenestration of the superior sagittal sinus at the level of the encephalocele, subependymal heterotopia, and thick tectum. The patient underwent resection and repair on day 2 of life. MRI performed at 15 weeks of life showed a mild increase in the size of lateral ventricles. The patient did not require a ventriculoperitoneal shunt. This is a novel case that provides a valuable contribution to the existing body of literature about congenital encephalocele associated with persistent falcine sinus, fenestrated superior sagittal sinus, subependymal heterotopia, and thick tectum.

Two cases of persistent falcine and occipital sinuses.

BACKGROUND: The coexistence of falcine and occipital sinuses is rare and its natural course has not been reported. CASE REPORTS: Two patients with persistent falcine and occipital sinuses are described. Both patients had straight sinuses. In one, both the transverse and sigmoid sinuses were hypoplastic and the patient had an acquired Chiari I malformation. The other patient had no other venous anomalies and had a normal posterior cranial fossa. CONCLUSION: The coexistence of falcine and occipital sinuses can lead to an acquired Chiari I malformation. These cases suggest the importance of checking other venous and brain anomalies in this situation.