Redefined role of angiogenesis in the pathogenesis of dural arteriovenous malformations

Dural arteriovenous fistulas of the occipital sinus secondary to trauma: Two case reports and a review of the literature

Background

Intracranial dural arteriovenous fistulas (DAVFs) involving the occipital sinus (OS) are rare vascular anomalies characterized by abnormal connections between meningeal arteries and venous sinuses or cortical veins. Trauma and venous hypertension are recognized factors in the pathogenesis of DAVFs, with previous injuries to the venous sinus and subsequent angiogenic responses contributing to abnormal arteriovenous shunt formation. The OS's variable anatomy and deep midline location add unique challenges to the diagnosis and treatment of DAVFs in this region.

Case Description

We report two cases of OS DAVFs in patients with a history of remote cranial trauma. The first case describes a 36-year-old man with a 3-year history of progressive headache, recently worsening with severe headache, nausea, and vomiting. Imaging revealed a DAVF at the OS with cortical venous reflux. After an unsuccessful attempt at transarterial embolization, transvenous embolization achieved near-complete obliteration, and the patient remained asymptomatic at the 3-year follow-up. The second case involves a 54-year-old man with a history of a high fall. He initially presented with bilateral leg numbness and urinary retention, progressing to quadriparesis. Imaging demonstrated an OS DAVF with spinal venous congestion and cervical cord compression. Following an unsuccessful transarterial approach, he underwent a suboccipital craniotomy with OS ligation. Despite complete obliteration, he remained significantly disabled at the 1-year follow-up.

Conclusion

These cases highlight the role of trauma in the development of OS DAVFs and the challenges associated with their management. Successful treatment often requires a combined approach due to complex arterial feeders and venous drainage patterns. Early intervention is crucial in preventing irreversible neurological deficits caused by prolonged venous congestion, emphasizing the need for timely diagnosis and individualized treatment strategies for DAVFs involving the OS.

Dural arteriovenous fistula may be occluded through recanalization of impaired venous sinuses

To investigate the effect and safety of recanalization of stenosed or occluded venous sinuses for dural arteriovenous fistulas (DAVFs) and possible mechanism of DAVF formation, patients with DAVF accompanied by venous sinus stenosis or occlusion treated with balloon angioplasty and/or stenting were retrospectively enrolled. The clinical data, treatment outcomes and complications were analyzed. In 7 patients enrolled, the DAVF was Cognard IIa grade in 3 (42.9% or 3/7) and IIa + b in 4 (57.1% or 4/7) patients, including complex DAVFs in 2 (28.6% or 2/7). The angioplasty procedure was successful in all (100%) patients, including complete cure in 3 (42.9% or 3/7) patients with the initial Cognard grade IIa, transformation from Cognard grade IIa + b to I in 2 (28.6% or 2/7) patients, and unchanged Cognard grade IIa + b in 2 (28.6% or 2/7) patients. The symptoms were all improved. At 3-month angiographic follow-up, 5 (71.4% or 5/7) cases were cured, whereas 2 cases still had grade I fistulas but no clinical symptoms. Staged embolization in 2 patients resulted in significant symptom improvement. At the last follow-up of a median 4 years, no clinical symptoms were present in 5 (71.4% or 5/7) patients, intermittent headache in 1 (14.3% or 1/7), and death from trauma in 1 (14.3% or 1/7). In conclusion, endovascular recanalization of occluded or stenosed venous sinuses using balloon angioplasty and stenting is able to induce occlusion of DAVFs and is a safe and efficient treatment approach for DAVFs which are possibly caused by significant pressure increase.

Microsurgical treatment for superior petrosal sinus dural arteriovenous fistulas

Superior petrosal sinus (SPS) dural arteriovenous fistulas (DAVFs) are a commonly encountered type of tentorial DAVF that occasionally requires microsurgical intervention. This study aims to analyze the tributaries of the superior petrosal vein (SPV) observed intraoperatively, their association with clinical symptoms, and venous drainage patterns. This retrospective study reviewed 34 consecutive patients with SPS DAVFs who underwent microsurgical treatment at a single institution between 2014 and 2022. The cohort had a mean age of 52.8 ± 11.8 years, with 85.3% (29/34) being male. Predominant symptoms included venous hypertensive myelopathy (VHM) (55.9%) and intraparenchymal or subarachnoid hemorrhage (23.5%). Standard retrosigmoid approach was used to ligate 94.1% (32/34) of the lesions, resulting in immediate complete fistula occlusion for all patients. Supratentorial venous drainage patterns were associated with a higher incidence of intracranial hemorrhage and venous varix (P = 0.047). Infratentorial drainage patterns were more frequently linked with VHM-related symptoms (P<0.001). Patients presenting VHM-related symptoms showed a higher prevalence of drainage through the vein of the cerebellopontine fissure (VCPF) (P = 0.01), while those with intracranial hemorrhage symptoms exhibited a higher prevalence of pontotrigeminal vein (PTV) drainage (P = 0.033) in their DAVFs. Endovascular management of SPS DAVFs carries inherent risks. Surgical treatment via standard retrosigmoid craniotomy offers favorable clinical outcomes with high rates of cure. In cases featuring infratentorial venous drainage, the predominant arterialized tributary of the SPV was the VCPF, commonly associated with VHM-related symptoms. Conversely, in cases with supratentorial venous drainage, the predominant arterialized SPV tributary was the PTV, often associated with intracranial hemorrhage symptoms.

Intracranial dural arteriovenous fistulas with pial arterial supply: A narrative review

Intracranial dural arteriovenous fistula (DAVF) is a relatively complex intracranial condition, and its clinical presentation and treatment strategies often vary significantly due to various factors. Although the cure rate of intracranial DAVF is currently high, there is still a lack of understanding of its etiology and pathogenesis. There is ongoing controversy regarding the treatment strategies for DAVF associated with the pial arteries, and there is a lack of understanding of its pathogenesis. The author conducted a brief literature review on DAVF with pial arterial supply and presented some treatment experiences from their own medical center. Large-scale retrospective cohort studies and prospective research in future are expected to address these issues.

Vasa vasorum: The role in intracranial physiology and pathophysiology

Background

Vasa vasorum (VVs) is a Latin word representing vessels of vessels. VVs are usually found on the adventitia of the parent vessel and infrequently reach the media and intima, depending on the size and type of the parent vessels and physiological and pathological conditions. The VVs include arteries, capillaries, veins, and lymphatic vessels, involving the oxygenation and nourishment of the vessel's wall to sustain its healthy state. Accumulated studies have revealed that VVs are involved in various intracranial lesions, including atherosclerotic diseases, aneurysms, and shunt diseases. The current review aims to review and integrate past and recent findings and knowledge on VVs and to facilitate our understanding of VVs and intracranial pathology involving VVs.

Methods

A literature review was carried out with a focus on the role of VVs by searching the Pubmed database.

Results

We identified 71 articles that discuss the role of VVs. We discussed the anatomical structure, physiological significance, and pathological significance of the VV.

Conclusion

VV is not only involved in the nutrition and metabolism of the vascular wall but is also deeply involved in the pathogenesis of inflammation, ischemia, and thrombosis of the vascular wall. In addition, in the central nervous system, intracranial vascular wall nutrient particularities and VVs are closely related to the pathogenesis of cerebral aneurysms, subarachnoid hemorrhage, arteriovenous shunt disease, atherosclerotic lesions, and other conditions.

Concurrent Moyamoya-like Intracranial Steno-Occlusive Disease and Dural Arteriovenous Fistulas

The simultaneous presentation of intracranial steno-occlusive disease, Moyamoya disease, or Moyamoya-like vasculopathy and dural arteriovenous fistulas (DAVFs) has been documented in very few case reports worldwide. We aimed to better characterize this association by reviewing the clinical and radiologic findings of 4 patients with concurrent intracranial steno-occlusive disease or Moyamoya-like vasculopathy and DAVFs evaluated in our institution. All 4 patients were of Asian descent. One patient presented with ischemic stroke secondary to intracranial stenosis, 2 presented with symptoms related to the DAVF, and the diagnosis was incidental in the fourth patient. Three patients underwent embolization of the DAVF, which was followed by surgical ligation in 2. One patient underwent extracranial-intracranial bypass for Moyamoya-like intracranial steno-occlusive disease. One patient is being managed conservatively with close follow-up. Our case series details findings in 4 patients with associated intracranial steno-occlusive disease and DAVFs. Further studies and reporting of similar cases are necessary to establish whether this is pure coincidence or if there is indeed a relationship between these 2 conditions, especially in certain ethnic groups.

Internal jugular vein fistula mimicking dural arteriovenous fistula after cardiac pacemaker placement

Carotid jugular arteriovenous fistulas are a documented complication of cannulation of the internal jugular vein. They may present with neck pain, headache, and cardiovascular aberrations. However, carotid jugular fistula secondary thrombus formation after jugular cannulation with radiographic presentation similar to dural arteriovenous fistula has not yet been reported in the literature. Below, we report the case of a 68-year-old male with an incidentally found carotid-jugular fistula secondary to pacemaker placement who had intracranial reflux on imaging, which was ultimately treated successfully through an endovascular approach.

Systemic immune-inflammation index in dural arteriovenous fistula: a feasible biomarker reflecting its clinical characteristics

PURPOSE

The systemic immune-inflammation index (SII), a marker of systemic inflammation, can be calculated using peripheral blood tests. Although the SII has been reported as a feasible biomarker in various cerebrovascular diseases, no studies have explored in dural arteriovenous fistula (DAVF). A retrospective cohort study was performed to test whether the SII reflects the clinical characteristics of DAVF and whether this index could serve as a feasible biomarker.

METHODS

This study included 28 patients who underwent endovascular treatment (39 sessions) for DAVF between 2014 and 2023. The SII was calculated using the following formula: platelet count multiplied by neutrophil count divided by lymphocyte count. We investigated the correlation between the SII and various clinical characteristics of DAVF, including symptom manifestation, and digital subtraction angiography findings. Additionally, we compared pre- and post-endovascular treatment changes in the SII.

RESULTS

A significantly higher SII was observed in patients with multiple lesions, clinical symptoms (particularly aggressive symptoms), pseudophelebitic pattern (PPP), and sinus occlusion. Multivariate regression analysis revealed that the presence of symptoms (coefficient 270.9, P = 0.021) and PPP (coefficient 272.4, P = 0.017) were independent factors contributing to SII elevation. Notably, following endovascular treatment, there was a significant decrease in the elevated SII in patients whose symptoms resolved (P = 0.039) and where the DAVF was angiographically cured (P = 0.012).

CONCLUSION

Elevation of the SII in patients with advanced DAVF and its decrease following endovascular treatment suggests that the SII reflects the disease condition and indicates its potential as a promising biomarker.

De novo formation of remote dural arteriovenous fistula following treated cavernous sinus dural arteriovenous fistula

Background

The development of new dural arteriovenous fistulas (DAVFs) at another location following endovascular treatment of cavernous sinus DAVFs (CSDAVFs) are extremely rare. Our aim is to review cases of de Novo DAVFs that occurred after treatment of CSDAVFs at our institution and those reported in the literature.

Methods

We reviewed all cases of CSDAVFs evaluated by 2 experienced neuroradiologists. A literature search was performed using the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines focusing on De Novo DAVFs following the endovascular treatment of cerebrovascular malformations. Addition articles were searched through the reference lists of the included articles.

Results

From June 2004 and September 2019., we identified 3 (2.5%) cases of De Novo DAVFs occurred after endovascular treatment or spontaneous obliteration of CSDAVFs from 119 treated CSDAVFs at our institute. Our review yielded 9 articles involving 12 patients with 15 de novo DAVFs, including our 3 patients. The mean age was 55.08 ± 12.9 years (range 43-69), 83.3% were females (n = 10). The new remote DAVFs occurred after endovascular treatment of CSDAVFs in 10 (83.3%) patients. The de novo DAVFs occurred following spontaneous complete regression in 2 (16.7%) patients. All de novo DAVFs developed after complete obliteration of treated CSDAVFs.

Conclusion

Sinus thrombosis and elevated venous pressure may play an important role in the pathogenesis of a de novo DAVF formation. In addition, thrombophilic abnormalities and the use of contraceptives may contribute to sinus thrombosis, leading to the development of the second remote DAVF after treatment of CSDAVFs.

Peripheral macrophages in the development and progression of structural cerebrovascular pathologies

The human cerebrovascular system is responsible for maintaining neural function through oxygenation, nutrient supply, filtration of toxins, and additional specialized tasks. While the cerebrovascular system has resilience imparted by elaborate redundant collateral circulation from supportive tertiary structures, it is not infallible, and is susceptible to developing structural vascular abnormalities. The causes of this class of structural cerebrovascular diseases can be broadly categorized as 1) intrinsic developmental diseases resulting from genetic or other underlying aberrations (arteriovenous malformations and cavernous malformations) or 2) extrinsic acquired diseases that cause compensatory mechanisms to drive vascular remodeling (aneurysms and arteriovenous fistulae). Cerebrovascular diseases of both types pose significant risks to patients, in some cases leading to death or disability. The drivers of such diseases are extensive, yet inflammation is intimately tied to all of their progressions. Central to this inflammatory hypothesis is the role of peripheral macrophages; targeting this critical cell type may lead to diagnostic and therapeutic advancement in this area. Here, we comprehensively review the role that peripheral macrophages play in cerebrovascular pathogenesis, provide a schema through which macrophage behavior can be understood in cerebrovascular pathologies, and describe emerging diagnostic and therapeutic avenues in this area.

Anticoagulation helps shrink giant venous lakes and arteriovenous fistulas in dural sinus malformation

BACKGROUND

Dural sinus malformations (DSMs) associated with high flow arteriovenous shunts are a challenging disease in babies that can lead to severe neurological damage or death. We report our treatment strategy in seven consecutive DSMs.

METHODS

We performed a retrospective analysis of seven consecutive patients from four centres, treated with transarterial embolization and anticoagulants.

RESULTS

Mean clinical and imaging follow-up was 2.8 years (IQR1-3 1.8-5.3). At baseline, the median size of the dilated venous pouch (giant lake) was 35 mm (IQR1-3 24-41) that decreased to a normal or near normal venous collector diameter of median size 11.5 mm (IQR1-3 8.5-13.8). This was achieved after a median of two embolization sessions targeted on dural feeders (IQR1-3 1.5-2.5), leaving associated pial feeders untreated. There were no cerebral hemorrhagic complications during the anticoagulation treatment. Median percentage of shunt remaining after embolization was 30% (IQR1-3 12-30), which spontaneously decreased with anticoagulation and even after discontinuation of anticoagulation, in parallel with the reduction in diameter of the dilated sinus, up to healing (or near healing). At the last clinical assessment, the modified Rankin Scale score was 0 in four patients, 1 in one patient, and 3 in two patients.

CONCLUSIONS

Anticoagulants may help to potentiate transarterial embolization in DSMs in babies by decreasing venous dilatation and reducing the remaining arteriovenous shunt, particularly the pial feeders. We did not observe recurrence of arteriovenous shunts after treatment, especially during anticoagulation treatment. Further studies are needed to support our findings.

Minor micro-rheological alterations in the presence of an artificial saphenous arteriovenous shunt, as an arteriovenous malformation model in the rat

BACKGROUND

Arteriovenous malformations (AVMs) are vascular anomalies characterized by abnormal shunting between arteries and veins. The progression of the AVMs and their hemodynamic and rheological relations are poorly studied, and there is a lack of a feasible experimental model.

OBJECTIVE

To establish a model that cause only minimal micro-rheological alterations, compared to other AV models.

METHODS

Sixteen female Sprague Dawley rats were randomly divided into control and AVM groups. End-to-end anastomoses were created between the saphenous veins and arteries to mimic AVM nidus. Hematological and hemorheological parameters were analyzed before surgery and on the 1st, 3rd, 5th, 7th, 9th, and 12th postoperative weeks.

RESULTS

Compared to sham-operated Control group the AVM group did not show important alterations in hematological parameters nor in erythrocyte aggregation and deformability. However, slightly increased aggregation and moderately decreased deformability values were found, without significant differences. The changes normalized by the 12th postoperative week.

CONCLUSIONS

The presented rat model of a small-caliber AVM created on saphenous vessels does not cause significant micro-rheological changes. The alterations found were most likely related to the acute phase reactions and not to the presence of a small-caliber shunt. The model seems to be suitable for further studies of AVM progression.

The Significance of Venous Outflow Obstruction in Dural Arteriovenous Fistulas

BACKGROUND AND OBJECTIVES

The association between venous outflow obstruction (VOO) and cranial dural arteriovenous fistulas (DAVF) is well established; however, its impact on the natural history remains unclear. This article aims to characterize its clinical significance and further describe the natural history of DAVF.

METHODS

A retrospective cohort study was performed at a tertiary neurosurgical center. Cohort characteristics were described with a focus on patients with VOO. Annualized event rates and risk factors for hemorrhage and nonhemorrhagic neurological events (NHNE) were also investigated.

RESULTS

The cohort consisted of 108 patients, 74 of which had follow-up greater than 1 month including 24 low-grade (Cognard I-IIa) fistulas (21.7 lesion-years) and 50 high-grade (Cognard IIb-V) fistulas (60 lesion-years). 18 patients with concurrent VOO were identified; most (83.3%) were high-grade DAVF and had obstruction of the direct draining sinus. Annualized rates of hemorrhage and NHNE for high-grade DAVF were 4.6% and 10.6%, respectively. Those high-grade lesions presenting with hemorrhage had a 10.9% annual rate of recurrent hemorrhage, while those presenting with NHNE had a 22.3% annual rate of subsequent NHNE. Fifteen high-grade DAVF with VOO (15.7 lesion-years) had annualized hemorrhage and NHNE rates of 6.4% and 31.9%, respectively. High radiological grade, an aggressive index presentation, and the presence of VOO were the predictors of hemorrhage and NHNE (P < .05).

CONCLUSION

This study reports a novel association between VOO and a more aggressive clinical course. DAVF with high-grade angiographic features, an aggressive index presentation, or VOO should be considered for early treatment.

An Illustrative Review of the Pathomechanisms of Symptomatic Developmental Venous Anomalies

OBJECTIVE

Symptomatic developmental venous anomalies (DVAs) are rare. Here, we illustrate the varied clinicoradiologic profiles of symptomatic DVAs and contemplate the mechanisms that render these (allegedly) benign entities symptomatic supported by a review of literature.

METHODS

Institutional databases were searched to identify cases of symptomatic DVAs. Clinical and imaging (angiographic and cross-sectional) data of 9 cases with 11 neurovascular symptoms consequent to inflow/outflow perturbations and mechanical obstruction that manifested because of the strategic topography of underlying DVAs were analyzed. A review of the existing literature on DVAs in agreement with our case series was performed on publications retrieved from the PubMed database.

RESULTS

Symptoms secondary to venous hypertension arising from flow-related perturbations were broadly divided into those arising from restricted outflow and increased inflow. Restricted outflow occurred because of collector vein stenosis (n = 2) and collector vein/DVA thrombosis (n = 3), whereas the latter pathomechanism was initiated by arterialized/transitional DVAs (n = 2). A mechanical/obstructive pathomechanism culminating in moderate supratentorial ventriculomegaly was noted in 1 case. One patient was given a diagnosis of hemorrhage associated with a cavernoma.

CONCLUSIONS

Awareness and contextualization of potential flow-related perturbations and mechanical insults that render DVAs symptomatic aid in accurate diagnosis, management, and prognostication.

De Novo Radicular Arteriovenous Fistula After Treatment of Spinal Arteriovenous Fistula: A Case Report and Literature Review

De novo spinal dural arteriovenous fistulas (AVFs) have been reported as metachronous AVFs However, metachronous spinal AVFs are extremely rare, and their pathogenesis remains uncertain. We report a case of de novo radicular AVF (RAVF) following treatment for spinal AVF at the craniocervical junction (CCJ). We also reviewed the literature and discussed the pathogenesis of metachronous spinal AVF. A 64-year-old male patient diagnosed with spinal AVF at the CCJ supplied from the right C1 segmental artery was treated with Onyx-18 (eV3 Inc, CA, USA) trans-arterial embolization, resulting in partial occlusion. Angiography showed a slight residual shunt two weeks after the embolization without another shunt lesion. A five-year follow-up spinal angiography showed de novo RAVF at the C4 level and complete occlusion of the first AVF. The second AVF was not treated because it was asymptomatic, and the patient remained asymptomatic. De novo RAVF was found to develop five years after the embolization of a CCJ-spinal AVF in a patient. This is the first case of de novo RAVF post-treatment of a spinal AVF. This case demonstrated that RAVF could develop as an acquired disease.

De novo progressive dural arteriovenous fistula with putamen hemorrhage associated with long-term Down syndrome: A case report and literature review

Dural arteriovenous fistula (DAVF) is considered an acquired change in blood flow related to factors such as craniotomy, trauma, and infection. However, several factors related to its development remain unknown. Here, we present a case of a 48-year-old man with Down syndrome and Eisenmenger syndrome. He had a history of craniotomy for multiple brain abscesses, followed by the occurrence of a de novo straight sinus (StS) DAVF within the last 2 years. The patient presented with right putamen hemorrhage due to venous congestion by a StS DAVF. The shunt flow was occluded by transarterial embolization using Onyx. Several studies have reported on DAVF models induced by venous congestion and hypoxemia. In this case, local venous congestion due to craniotomy for multiple brain abscesses was considered as one of the causes of DAVF. Complication of venous thrombosis or chronic hypoxemia due to Eisenmenger syndrome might have led to its progression. Especially in DAVF cases with Down syndrome, concomitant symptoms such as hypoxemia due to congenital heart failure and coagulopathy could worsen the disease state progressively.

Intracranial Dural Arteriovenous Fistulas

Dural arteriovenous fistulas (DAVFs) are abnormal communications between meningeal arteries and dural venous sinuses and/or cortical veins. Although many fistulas are benign and do not require treatment, some may carry a significant risk of bleeding or cause symptoms and warrant treatment. This review provides a review of various aspects of intracranial DAVFs including epidemiology, pathophysiology, clinical presentation, imaging characteristics, classification, natural history, and management options. By exploring these topics, we aim to enhance understanding of this condition and facilitate patient care.

Association between Dural AVFs and Cerebral Venous Thrombosis

BACKGROUND AND PURPOSE

Recent reports suggest an association between dural AVFs and cerebral venous thrombosis. We aimed to investigate the specific temporal and anatomic association between the 2 conditions.

MATERIALS AND METHODS

A consecutive cohort of adult patients with dural AVFs was seen at Amsterdam University Medical Centers (2007-2020). An experienced neuroradiologist re-evaluated the presence and imaging characteristics of dural AVFs and cerebral venous thrombosis on all available imaging. The temporal (previous/concurrent/subsequent) and anatomic (same/adjacent/unrelated venous sinus or vein) association between dural AVFs and cerebral venous thrombosis was determined.

RESULTS

Among 178 patients with dural AVFs, the mean age was 58.3 (SD, 13.2) years and 85 (48%) were women. Of 55 patients (31%) with cerebral venous thrombosis, 34 (62%) were women. Four patients (7%) had cerebral venous thrombosis before the development of a dural AVF, 33 (60%) had cerebral venous thrombosis at the time of dural AVF diagnosis (concurrent), and 18 (33%) developed cerebral venous thrombosis during follow-up after conservative treatment. The incidence rate of cerebral venous thrombosis after a dural AVF was 79 per 1000 person-years (95% CI, 50-124). In 45 (82%) patients with dural AVFs and cerebral venous thrombosis, the thrombosis was located in the same venous sinus as the dural AVF, whereas in 8 (15%) patients, thrombosis occurred in a venous sinus adjacent to the dural AVF.

CONCLUSIONS

One-third of patients with a dural AVF in this study were diagnosed with cerebral venous thrombosis. In almost two-thirds of patients, cerebral venous thrombosis was diagnosed prior to or concurrent with the dural AVF. In 97% of patients, there was an anatomic association between the dural AVF and cerebral venous thrombosis. These data support the hypothesis of a bidirectional association between the 2 diseases.

Petrous apex's dural arteriovenous fistula (DAVF) mimicking a pineal region tumour: a rare cause of Hakim triad

A dural arteriovenous fistula (DAVF) is a dural-based shunt between meningeal arteries and meningeal veins, sinuses and/or cortical veins; they have been classified and named according to the location and the flow pattern. Petrous apex DAVFs are located where the petrosal vein penetrates the dura mater into the superior petrosal sinus; there are only few cases reported in the literature, they can show an aggressive behaviour (subarachnoid haemorrhage, severe brainstem oedema) with a high mortality rate. The described case is, to the best of our knowledge, the first case of a DAVF presenting with symptoms mimicking idiopathic normal pressure hydrocephalus. After worsening of gait impairment, memory loss and urinary incontinence an urgent CT of the brain showed hydrocephalus and a hyperdense mass in the pineal region mimicking a pineal tumour; an emergent digital subtraction angiogram showed a left petrous apex Borden type III DAVF. A transvenous embolisation was performed obtaining a complete obliteration.

Venous stroke–a stroke subtype that should not be ignored

Based on the etiology, stroke can be classified into ischemic or hemorrhagic subtypes, which ranks second among the leading causes of death. Stroke is caused not only by arterial thrombosis but also by cerebral venous thrombosis. Arterial stroke is currently the main subtype of stroke, and research on this type has gradually improved. Venous thrombosis, the particular type, accounts for 0.5–1% of all strokes. Due to the lack of a full understanding of venous thrombosis, as well as its diverse clinical manifestations and neuroimaging features, there are often delays in admission for it, and it is easy to misdiagnose. The purpose of this study was to review the pathophysiology mechanisms and clinical features of arterial and venous thrombosis and to provide guidance for further research on the pathophysiological mechanism, clinical diagnosis, and treatment of venous thrombosis. This review summarizes the pathophysiological mechanisms, etiology, epidemiology, symptomatology, diagnosis, and treatment heterogeneity of venous thrombosis and compares it with arterial stroke. The aim is to provide a reference for a comprehensive understanding of venous thrombosis and a scientific understanding of various pathophysiological mechanisms and clinical features related to venous thrombosis, which will contribute to understanding the pathogenesis of intravenous stroke and provide insight into diagnosis, treatment, and prevention.

New insight into DAVF pathology—Clues from meningeal immunity

In recent years, with the current access in techniques, studies have significantly advanced the knowledge on meningeal immunity, revealing that the central nervous system (CNS) border acts as an immune landscape. The latest concept of meningeal immune system is a tertiary structure, which is a comprehensive overview of the meningeal immune system from macro to micro. We comprehensively reviewed recent advances in meningeal immunity, particularly the new understanding of the dural sinus and meningeal lymphatics. Moreover, based on the clues from the meningeal immunity, new insights were proposed into the dural arteriovenous fistula (DAVF) pathology, aiming to provide novel ideas for DAVF understanding.

Remodeling of the Neurovascular Unit Following Cerebral Ischemia and Hemorrhage

Formulated as a group effort of the stroke community, the transforming concept of the neurovascular unit (NVU) depicts the structural and functional relationship between brain cells and the vascular structure. Composed of both neural and vascular elements, the NVU forms the blood-brain barrier that regulates cerebral blood flow to meet the oxygen demand of the brain in normal physiology and maintain brain homeostasis. Conversely, the dysregulation and dysfunction of the NVU is an essential pathological feature that underlies neurological disorders spanning from chronic neurodegeneration to acute cerebrovascular events such as ischemic stroke and cerebral hemorrhage, which were the focus of this review. We also discussed how common vascular risk factors of stroke predispose the NVU to pathological changes. We synthesized existing literature and first provided an overview of the basic structure and function of NVU, followed by knowledge of how these components remodel in response to ischemic stroke and brain hemorrhage. A greater understanding of the NVU dysfunction and remodeling will enable the design of targeted therapies and provide a valuable foundation for relevant research in this area.

De novo dural arteriovenous fistula after mechanical thrombectomy for cerebral venous thrombosis: A case report

Background:

Although the relationship between dural arteriovenous fistula (dAVF) and cerebral venous thrombosis (CVT) has been reported, the etiology has not been clarified. Here, we report a case of de novo dAVF after mechanical thrombectomy for CVT and discuss the underlying mechanism.

Case Description:

A 61-year-old woman presented with a gradually worsening headache and was diagnosed with severe CVT. Mechanical thrombectomy was performed for the CVT because of progressive neurological deterioration despite anticoagulation therapy. Two years after the initial treatment, angiography revealed a de novo dAVF with a direct shunt of the left convexity cortical vein. Transarterial embolization with Onyx was performed and the shunt was completely obliterated.

Conclusion:

In this report, we describe a case of de novo dAVF with CVT that was treated with mechanical thrombectomy. Even if CVT improves with mechanical thrombectomy, we must be aware of the occurrence of de novo dAVF.

Sphenoparietal Sinus Dural Arteriovenous Fistulas: A Series of 10 Patients

BACKGROUND

Dural arteriovenous fistulas (DAVFs) of the sphenoparietal sinus or sphenoid wing region are uncommon lesions with unique and interesting angioarchitecture. Understanding appropriate anatomy and recognizing patterns provide important treatment implications.

OBJECTIVE

To describe a single surgeon's experience with open surgical treatment of sphenoparietal sinus DAVFs, the surgical indications for this uncommon lesion, and the microsurgical techniques related to its treatment and to review the literature on its surgical treatment.

METHODS

Consecutive cases of sphenoparietal sinus DAVF treatment conducted by a single surgeon over 24 years (1997-2020) were retrospectively reviewed. Published reports of similar cases were reviewed.

RESULTS

Of 202 surgically treated DAVFs, 10 lesions in 10 patients were sphenoparietal sinus DAVFs. Four patients presented with intracranial hemorrhage, 3 with headache, and 2 with pulsatile tinnitus; 1 patient was incidentally identified as having a DAVF during treatment for a ruptured aneurysm. Most patients (7 of 10) had undergone endovascular embolization previously. Nine patients had Borden type III DAVFs and one had a Borden type II fistula. Surgery in all 10 patients resulted in angiographically confirmed fistula obliteration. Clinical outcomes at the last follow-up, measured by a modified Rankin Scale (mRS) score, were excellent in 6 patients (mRS ≤ 2) and poor in 1 patient (mRS ≥ 3); late outcomes were not available for 3 patients.

CONCLUSION

Sphenoparietal sinus DAVFs are an uncommon anatomic subtype. Careful attention to angiographic detail leads to identification of the site of venous interruption and results in a high rate of surgical cure with excellent clinical outcomes.

Novel experimental model of brain arteriovenous malformations using conditional Alk1 gene deletion in transgenic mice

OBJECTIVE

Hereditary hemorrhagic telangiectasia is the only condition associated with multiple inherited brain arteriovenous malformations (AVMs). Therefore, a mouse model was developed with a genetics-based approach that conditionally deleted the causative activin receptor-like kinase 1 (Acvrl1 or Alk1) gene. Radiographic and histopathological findings were correlated, and AVM stability and hemorrhagic behavior over time were examined.

METHODS

Alk1-floxed mice were crossed with deleter mice to generate offspring in which both copies of the Alk1 gene were deleted by Tagln-Cre to form brain AVMs in the mice. AVMs were characterized using MRI, MRA, and DSA. Brain AVMs were characterized histopathologically with latex dye perfusion, immunofluorescence, and Prussian blue staining.

RESULTS

Brains of 55 Tagln-Cre+;Alk12f/2f mutant mice were categorized into three groups: no detectable vascular lesions (group 1; 23 of 55, 42%), arteriovenous fistulas (AVFs) with no nidus (group 2; 10 of 55, 18%), and nidal AVMs (group 3; 22 of 55, 40%). Microhemorrhage was observed on MRI or MRA in 11 AVMs (50%). AVMs had the angiographic hallmarks of early nidus opacification, a tangle of arteries and dilated draining veins, and rapid shunting of blood flow. Latex dye perfusion confirmed arteriovenous shunting in all AVMs and AVFs. Microhemorrhages were detected adjacent to AVFs and AVMs, visualized by iron deposition, Prussian blue staining, and macrophage infiltration using CD68 immunostaining. Brain AVMs were stable on serial MRI and MRA in group 3 mice (mean age at initial imaging 2.9 months; mean age at last imaging 9.5 months).

CONCLUSIONS

Approximately 40% of transgenic mice satisfied the requirements of a stable experimental AVM model by replicating nidal anatomy, arteriovenous hemodynamics, and microhemorrhagic behavior. Transgenic mice with AVFs had a recognizable phenotype of hereditary hemorrhagic telangiectasia but were less suitable for experimental modeling. AVM pathogenesis can be understood as the combination of conditional Alk1 gene deletion during embryogenesis and angiogenesis that is hyperactive in developing and newborn mice, which translates to a congenital origin in most patients but an acquired condition in patients with a confluence of genetic and angiogenic events later in life. This study offers a novel experimental brain AVM model for future studies of AVM pathophysiology, growth, rupture, and therapeutic regression.

Cerebral venous sinus thrombosis and dural arteriovenous fistula associated with protein S deficiency: a case series study

OBJECTIVE

To describe the characteristics of patients with cerebral venous sinus thrombosis (CVST) and dural arteriovenous fistula (AVF) associated with protein S (PS) deficiency.

METHODS

We conducted a search of medical records in Hainan General Hospital from January 2000 to December 2020 for coexistence of CVST and dural AVF associated with PS deficiency and searched PubMed、Embase and Chinese biomedical databases (CBM) for all literature describing CVST and dural AVF with PS. We analyzed clinical characteristics, location, sequence of CVST and dural AVF, level of PS, therapeutic methods and prognosis.

RESULTS

We presented 1 patient in our hospital's database combined CVST and dural AVF associated with PS, plus 5 cases reported in literature. The most common symptoms were headache, generalized seizure, disturbance of consciousness. The most frequent location of CVST was at internal cerebral vein, while transverse sinus, sigmoid sinus, parietal region in dural AVF. Two patients developed dural AVF several months or years after CVST. Clinical characteristics and level of PS were summarized.

CONCLUSION

These findings alert physicians to consider PS deficiency in patients who suffer from CVST, especially those combined with dural AVF.

Coexistence of anterior cranial fossa dural arteriovenous fistula and arteriovenous malformation with the same drainage system: illustrative case

BACKGROUND

The authors report a rare case of coexistence of dural arteriovenous fistula (DAVF) and arteriovenous malformation (AVM), with a common trunk drainer from both DAVF and AVM in the left anterior cranial fossa (ACF) with simple DAVF in the right ACF.

OBSERVATIONS

A 63-year-old female presented with seizure. Cerebral angiography showed bilateral DAVFs in the ACF and AVM in the left frontal lobe. A dilated frontal vein acted as a simple drainer of the right DAVF. In contrast, a dilated vein with large varix was the common drainer of both the left DAVF and the AVM. During surgery, indocyanine green videoangiography was performed with direct observation. In the left ACF, the drainer occlusion of the DAVF resulted in partial shrinkage of the varix and decreased distal blood flow. Additional main feeder occlusion of the AVM could decrease the blood flow further, but not completely because of the residual pial supplies for the AVM. Finally, the nidus of the AVM with varix was removed by en bloc resection.

LESSONS

Neurosurgeons should be aware of the coexistence of DAVF and AVM with a common trunk drainer. Only simple occlusion of the drainer from DAVF is not sufficient, so removal of the AVM is essential.

State of the Art and Future Direction in Diagnosis, Molecular Biology, Genetics, and Treatment of Brain Arteriovenous Malformations

Brain arteriovenous malformations (bAVMs) are uncommon and represent a heterogeneous group of lesions. Although these 2 facts have delayed research on this topic, knowledge about the pathophysiology, diagnosis, and treatment of bAVMs has evolved in recent years. We conducted a review of the literature to update the knowledge about diagnosis, molecular biology, genetic, pathology, and treatment by searching for the following terms: "Epidemiology AND Natural History," "risk of hemorrhage," "intracranial hemorrhage," "diagnosis," "angiogenesis," "molecular genetics," "VEGF," "KRAS," "radiosurgery," "endovascular," "microsurgery," or "surgical resection." Our understanding of bAVMs has significantly evolved in recent years. The latest investigations have helped in defining some molecular pathways involved in the pathology of bAVM. Although there is still more to learn and discover, describing these pathways will allow the creation of targeted treatments that could improve the prognosis of patients with bAVMs.

Endovascular Management of Intracranial Dural AVFs: Principles

Intracranial dural AVFs are abnormal communications between arteries that supply the dura mater and draining cortical veins or venous sinuses. They are believed to form as a response to venous insults such as thrombosis, trauma, or infection. Classification and management are dependent on the presence of drainage/reflux into cortical veins because such drainage markedly elevates the risk of hemorrhage or venous congestion, resulting in neurologic deficits. AVFs with tolerable symptoms and benign drainage patterns can be managed conservatively. Intolerable symptoms, presentation with hemorrhage/neurologic deficits, or aggressive drainage patterns are indications for intervention. Treatment options include microsurgical disconnection, endovascular transarterial embolization, transvenous embolization, or a combination. This is the first in a series of 3 articles on endovascular management of intracranial dural AVFs, in which we outline the principles and outcomes of endovascular treatment.

Trigeminal neuralgia secondary to arteriovenous malformation in the brainstem: a case report and a brief review

Trigeminal neuralgia, a condition characterized by high intensity, paroxysmal and unilateral pain, can be characterized as secondary when associated with conditions such as multiple sclerosis and tumors. However, among these secondary cases, there are also arteriovenous malformations, characterized by a nidus mass of vessels separated by parts of sclerotic tissues, responsible for a small portion of the neuralgias of the trigeminal nerve. The case report described is of a 54-year-old male patient who has a brainstem AVM and refers to lancing and paroxysmal pain in the right hemiface in the territories of V2 and V3 after feeding and brushing the teeth. The treatment of this patient was done from the insertion of a balloon from the foramen ovale, accessed by the Meckel fossa and the trigeminal ganglion. The literature review demonstrated, from the analysis of gender, age, vascularization, localization and treatments of reports of TGN secondary to brainstem AVM, the reduced number of cases described.

Dural arteriovenous fistulas in cerebral venous thrombosis: Data from the International Cerebral Venous Thrombosis Consortium

BACKGROUND AND PURPOSE

To explore the prevalence, risk factors, time correlation, characteristics and clinical outcome of dural arteriovenous fistulas (dAVFs) in a cerebral venous thrombosis (CVT) population.

METHODS

We included patients from the International CVT Consortium registries. Diagnosis of dAVF was confirmed centrally. We assessed the prevalence and risk factors for dAVF among consecutive CVT patients and investigated its impact on clinical outcome using logistic regression analysis. We defined poor outcome as modified Rankin Scale score 3-6 at last follow-up.

RESULTS

dAVF was confirmed in 29/1218 (2.4%) consecutive CVT patients. The median (interquartile range [IQR]) follow-up time was 8 (5-23) months. Patients with dAVF were older (median [IQR] 53 [44-61] vs. 41 [29-53] years; p < 0.001), more frequently male (69% vs. 33%; p < 0.001), more often had chronic clinical CVT onset (>30 days: 39% vs. 7%; p < 0.001) and sigmoid sinus thrombosis (86% vs. 51%; p < 0.001), and less frequently had parenchymal lesions (31% vs. 55%; p = 0.013) at baseline imaging. Clinical outcome at last follow-up did not differ between patients with and without dAVF. Additionally, five patients were confirmed with dAVF from non-consecutive CVT cohorts. Among all patients with CVT and dAVF, 17/34 (50%) had multiple fistulas and 23/34 (68%) had cortical venous drainage. Of 34 patients with dAVF with 36 separate CVT events, 3/36 fistulas (8%) were diagnosed prior to, 20/36 (56%) simultaneously and 13/36 after (36%, median 115 [IQR 38-337] days) diagnosis of CVT.

CONCLUSIONS

Dural arteriovenous fistulas occur in at least 2% of CVT patients and are associated with chronic CVT onset, older age and male sex. Most CVT-related dAVFs are detected simultaneously or subsequently to diagnosis of CVT.

The role of mural cells in hemorrhage of brain arteriovenous malformation

Brain arteriovenous malformation (bAVM) is the most common cause of intracranial hemorrhage (ICH), particularly in young patients. However, the exact cause of bAVM bleeding and rupture is not yet fully understood. In bAVMs, blood bypasses the entire capillary bed and directly flows from arteries to veins. The vessel walls in bAVMs have structural defects, which impair vascular integrity. Mural cells are essential structural and functional components of blood vessels and play a critical role in maintaining vascular integrity. Changes in mural cell number and coverage have been implicated in bAVMs. In this review, we discussed the roles of mural cells in bAVM pathogenesis. We focused on 1) the recent advances in human and animal studies of bAVMs; 2) the importance of mural cells in vascular integrity; 3) the regulatory signaling pathways that regulate mural cell function. More specifically, the platelet-derived growth factor-B (PDGF-B)/PDGF receptor-β (PDGFR-β), EphrinB2/EphB4, and angiopoietins/tie2 signaling pathways that regulate mural cell-recruitment during vascular remodeling were discussed in detail.

Variations and management for patients with craniocervical junction arteriovenous fistulas: Comparison of dural, radicular, and epidural arteriovenous fistulas

Background:

Craniocervical junction arteriovenous fistulas (CCJAVFs) are known to be rare, but variations and clinical behaviors remain controversial.

Methods:

A total of 11 CCJAVF patients (M: F=9:2, age 54–77 years) were investigated. Based on the radiological and intraoperative findings, they were categorized into three types: dural AVF (DAVF), radicular AVF (RAVF), and epidural AVF (EDAVF).

Results:

There were four symptomatic patients (subarachnoid hemorrhage in two, myelopathy in one, and tinnitus in one) and seven asymptomatic patients in whom coincidental CCJAVFs were discovered on imaging studies for other vascular diseases (arteriovenous malformation in one, intracranial DAVF in two, ruptured cerebral aneurysm in two, and carotid artery stenosis in two). Of these 11 patients, 2 (18.2%) had multiple CCJAVFs. Of 14 lesions, the diagnoses were DAVF in 5, RAVF in 3, and EDAVF in 6 (C1–C2 level ratio =5:0, 2:1, 3:3). Patients with DAVF/RAVF in four lesions with intradural venous reflux underwent surgery, although an RAVF remained in one lesion after embolization/radiation. Since all six EDAVFs, two DAVFs, and one RAVF had neither feeder aneurysms nor significant symptoms, no treatment was provided; of these nine lesions, one DAVF and one RAVF remained unchanged, whereas six EDAVFs showed spontaneous obliteration within a year. Unfortunately, however, one DAVF bled before elective surgery.

Conclusion:

CCJAVFs have many variations of shunting site, angioarchitecture, and multiplicity, and they were frequently associated with coincidental vascular lesions. For symptomatic DAVF/RAVF lesions with intradural drainage, surgery is preferred, whereas asymptomatic EDAVFs without dangerous drainage may obliterate during their natural course.

Spontaneous regression of a symptomatic developmental venous anomaly with capillary stain

BACKGROUND

Developmental venous anomalies are considered benign lesions; however, they can become symptomatic. A capillary stain, which is an atypical angiographical feature of developmental venous anomalies, is reported to be relevant to symptomatic developmental venous anomalies.

CASE DESCRIPTION

A 20-year-old man with no pertinent medical history had an epileptic seizure. Magnetic resonance imaging showed severe focal oedema and gadolinium contrast enhancement in the right precentral gyrus and inferior frontal gyrus adjacent to the Sylvian fissure, indicating venous congestion; these presentations had not been observed on magnetic resonance imaging 8 months before. Digital subtraction angiography revealed a developmental venous anomaly with capillary stain. After conservative treatment, the brain oedema resolved spontaneously and contrast enhancement of the lesion reduced significantly.

CONCLUSION

We report a rare case of a symptomatic developmental venous anomaly with unique radiological characteristics and its natural and clinical evolution. Despite the presence of a capillary stain, our patient exhibited temporary exacerbations and spontaneous regression, suggesting that the capillary stain was associated with a reversible condition. This is the first report to detail the spatiotemporal changes of a developmental venous anomaly with capillary stain through imaging, suggesting that regular follow-up imaging is warranted in the management of patients with developmental venous anomalies.

Cerebral venous drainage in patients with dural arteriovenous fistulas: correlation with clinical presentation

OBJECTIVE

Dural arteriovenous fistulas (DAVFs) are abnormal, acquired arteriovenous connections within the dural leaflets. Their associated symptoms may be mild or severe and are related to the patient's venous anatomy. With the hypothesis that the patient's venous anatomy determines the development of symptoms, the authors aimed to identify which venous anatomy elements are important in the development of major symptoms in patients with a DAVF.

METHODS

A multicenter study was performed based on the retrospective analysis of cerebral angiographies with systematic assessment of brain drainage pathways (including fistula drainage) in patients over 18 years of age with a single DAVF. The patients were divided into two groups: those with minor (group 1, n = 112) and those with major (group 2, n = 89) symptoms. Group 2 was subdivided into two groups: patients with hemorrhage (group 2a, n = 47) and patients with severe nonhemorrhagic symptoms (group 2b, n = 42).

RESULTS

The prevalence of stenosis in DAVF venous drainage and the identification of tiny anastomoses between venous territories were significantly higher in group 2 (32.6% and 19.1%, respectively) compared with group 1 (2.68% and 5.36%, respectively). Stenosis of DAVF venous drainage was significantly more frequent in group 2a than in group 2b (51.1% vs 11.9%, p < 0.001). Group 2b patients had increased prevalence of shared use of the cerebral main drainage pathway (85.0% vs 53.2%, p = 0.002), the absence of an alternative route (45.0% vs 17.0%, p = 0.004), and the presence of contrast stagnation (62.5% vs 29.8%, p = 0.002) compared with group 2a patients. In patients with high-grade fistulas, the group with major symptoms had increased prevalence of a single draining direction (31.3% vs 8.33%, p = 0.003), stenosis in the draining vein (35.0% vs 6.25%, p = 0.000), the absence of an alternative pathway for brain drainage (31.3% vs 12.5%, p = 0.017), and the presence of contrast stagnation (48.8% vs 22.9%, p = 0.004).

CONCLUSIONS

Major symptoms were observed when normal brain tissue venous drainage was impaired by competition with DAVF (predominance in group 2b) or when DAVF venous drainage had anatomical characteristics that hindered drainage, with consequent venous hypertension on the venous side of the DAVF (predominance in group 2a). The same findings were observed when comparing two groups of patients with high-grade lesions: those with major versus those with minor symptoms.

De Novo Dural Arteriovenous Fistula on Draining Veins of Previously Treated Pial Arteriovenous Malformation: a Case Report

A 71-year-old man, with a pial micro-arteriovenous malformation (pAVM) draining into the confluence of the vein of Trolard and the vein of Labbé was surgically removed, sparing these cortical veins. 4-months MR and angiographic controls showed a de novo dural arteriovenous fistula (dAVF) draining into the previously spared cortical veins. It was removed using intraoperative motor evoked potentials (MEP). This is the first case of iatrogenic dAVF developing on the same draining vein of a previously treated pAVM. De novo dAVFs are generally iatrogenic. This case suggests that the unresected venous drainage of an AVM might be the substratum for neo-angiogenetic processes; moreover inflammation related to surgery might be the trigger factor for the development of the dAVF.

Dural arteriovenous fistula formation following bilateral middle meningeal artery embolization for the treatment of a chronic subdural hematoma: a case report

Here is reported a case of dural arteriovenous fistula (DAVF) formation following middle meningeal artery (MMA) embolization. A 64-year-old male patient was operated for a bilateral CSDH by burr-hole craniostomy. Prophylactic post-operative MMA embolization was performed with 300-500-μm calibrated microparticles. The patient was admitted 3 months later for a left CSDH recurrence. Digital subtraction angiography demonstrated formation of a superior sagittal sinus DAVF fed by both superficial temporal arteries. This case highlights the possible role of local tissue hypoxia as a significant component of DAVF pathogenesis. Moreover, it has potential implications for MMA embolization as a management strategy for CSDH.

Brain vascular biology

The complex development of the brain vascular system can be broken down by embryonic stages and anatomic locations, which are tightly regulated by different factors and pathways in time and spatially. The adult brain is relatively quiescent in angiogenesis. However, under disease conditions, such as trauma, stroke, or tumor, angiogenesis can be activated in the adult brain. Disruption of any of the factors or pathways may lead to malformed vessel development. In this chapter, we will discuss factors and pathways involved in normal brain vasculogenesis and vascular maturation, and the pathogenesis of several brain vascular malformations.

Perimedullary arteriovenous fistulas of the craniovertebral junction: A systematic review

Perimedullary arteriovenous fistulas (PMAVFs) are uncommon vascular malformations, and they rarely occur at the level of the craniovertebral junction (CVJ). The therapeutic management is challenging and can include observation alone, endovascular occlusion, or surgical exclusion, depending on both patient and malformation characteristics. A systematic literature search was conducted using MEDLINE, Scopus, and Google Scholar databases, searching for the following combined MeSH terms: (perimedullary arteriovenous fistula OR dural arteriovenous shunt) AND (craniocervical junction OR craniovertebral junction). We also present an emblematic case of PMAVF at the level of the craniovertebral junction associated to a venous pseudoaneurysm. A total of 31 published studies were identified; 10 were rejected from our review because they did not match our inclusion criteria. Our case was not included in the systematic review. We selected 21 studies for this systematic review with a total of 58 patients, including 20 females (34.5%) and 38 males (65.5%), with a female/male ratio of 1:1.9. Thirty-nine out of 58 patients underwent surgical treatment (67.2%), 15 out of 58 patients were treated with endovascular approach (25.8%), 3 out of 58 patients underwent combined treatment (5.2%), and only 1 patient was managed conservatively (1.7%). An improved outcome was reported in 94.8% of cases (55 out of 58 patients), whereas 3 out of 58 patients (5.2%) were moderately disabled after surgery and endovascular treatment. In literature, hemorrhagic presentation is reported as the most common onset (subarachnoid hemorrhage in 63% and intramedullary hemorrhage in 10%), frequently caused either by venous dilation, due to an ascending drainage pathway into an intracranial vein, or by the higher venous flow rates that can be associated with intracranial drainage. Hiramatsu and Sato stated that arterial feeders from the anterior spinal artery (ASA) and aneurysmal dilations are associated with hemorrhagic presentation. In agreement with the classification by Hiramatsu, we defined the PMAVF of the CVJ as a vascular lesion fed by the radiculomeningeal arteries from the vertebral artery and the spinal pial arteries from the ASA and/or lateral spinal artery. Considering the anatomical characteristics, we referred to our patient as affected by PMAVF, even if it was difficult to precisely localize the arteriovenous shunts because of the complex angioarchitecture of the fine feeding arteries and draining veins, but we presumed that the shunt was located in the point of major difference in vessel size between the feeding arteries and draining veins. PMAVFs of CVJ are rare pathologies of challenging management. The best diagnostic workup and treatment are still controversial: more studies are needed to compare different therapeutic strategies concerning both long-term occlusion rates and outcomes.

Angio-architecture of complex cranial dural arteriovenous fistulas: A single centre retrospective review of treatment modalities and outcomes

INTRODUCTION

Cranial dural arteriovenous fistulas (DAVFs) are rare vascular lesions that often harbour complex angio-architectural features. This subtype of DAVF may require multiple, multimodality, or hybrid treatments. In this paper we aim to identify specific angio-architectural features that are present in complex cranial DAVFs and we report our series with respect to treatment modalities and outcomes.

METHODS

Twenty-five cranial Borden type II and III cranial DAVFs were treated at our Institution from 2013 to 2017. We classified nine (36%) as complex based on specific angio-architectural features. Treatment strategies were based on fistula location, angiographic features and patient's presenting condition. Phone interviews were used to confirm outcome at 6 and 12 months.

RESULTS

Four patients (45%) presented with acute hydrocephalus, and 3 (33%) with intracranial hemorrhage. Multiple and combined treatment sessions were needed for all complex DAVFs. Five patients required 2 endovascular procedures each. One patient had 2 surgeries. The first line of treatment was endovascular in 6 cases (67%) and surgery in 3 (33%). Two treatment-related (22%) complications occurred. Complete disconnection was achieved in 5 out of 9 patients (55%). Two patients with an incomplete disconnection refused further treatment and were well at last follow up, with a partially treated fistula and persistent CVR. The other 3 patients concluded treatment after the end of our data collection period. At 1 year, 7/9 patients had stable or improved clinical symptoms, and 8/9 patients had GOS of 4 or 5.

CONCLUSIONS

Complex cranial DAVF often require a multidisciplinary approach and multiple treatment sessions should be expected. Specific angio-architectural features that increase DAVF complexity include multiple arterial feeders, especially transosseous or pial, reflux into multiple cortical veins, sinus occlusion/entrapment, venous aneurysms, segmental stenosis, medial or deep location, and association with the deep venous system.

Intraosseous Cannulation of a Calvarial Diploic Vein for Embolization of a Symptomatic Dural Arteriovenous Fistula: A Technical Case Report

BACKGROUND AND IMPORTANCE

Dural arteriovenous fistulas (DAVFs) may present unique challenges for treatment depending on the anatomy and pattern of venous drainage. If endovascular techniques are to be employed, the DAVF must be amenable to transvenous or transarterial therapy. When access of peripheral vasculature does not provide a straightforward path, less conventional options may be available. This case highlights a novel, technically simple, and effective approach for the treatment of a subset of DAVFs, with venous drainage through calvarial diploic veins, that would make endovascular treatment otherwise challenging or impossible.

CLINICAL PRESENTATION

We present a case of a 66-yr-old female patient who was diagnosed with a symptomatic DAVF located along the sphenoid ridge with a large intraosseous channel containing the draining vein of the fistula. This lesion was successfully treated with transcranial endovascular embolization via direct intraosseous cannulation of the calvarial diploic vein. This novel approach obviated the need for a full-thickness craniotomy, afforded only minimal bone loss, and preserved the integrity of the dura. A 3-mo follow-up angiogram confirmed complete cure of the DAVF with no residual arteriovenous shunt. At 20 mo postembolization, the patient was symptom free, with no reported neurologic deficits. Complete diagnostic work-up, treatment planning in a multidisciplinary environment, and a novel approach for endovascular embolization utilizing a hybrid operating suite played key roles in the successful implementation of this technique.

CONCLUSION

This is the first report of direct intraosseous cannulation of a calvarial diploic vein for successful transcranial endovascular embolization of a symptomatic DAVF.

Subdural hematoma from an acquired dural arteriovenous fistula following external ventricular drain placement for subarachnoid hemorrhage

Objective: Intracranial dural arteriovenous fistulas represent pathological connections between dural arteries and dural veins, dural sinuses or meningeal veins in the absence of an intervening capillary bed. They are thought to be acquired secondary to trauma, surgery, sinus thrombosis, venous hypertension or arterial dysplasia. Methods: A 66-year-old Asian female presented with subarachnoid hemorrhage secondary to ruptured 2-mm saccular aneurysm of the left middle cerebral artery associated with fusiform dilatation. It was successfully treated with endovascular coiling. A right frontal external ventricular drain was also placed to treat her hydrocephalus. On post-bleed day 10, she became acutely unresponsive with a fixed and dilated right pupil. Head CT was obtained and revealed an acute right subdural hematoma which was emergently evacuated. Results: No obvious bleeders were identified during surgery. Patient improved and repeat catheter angiography a week later showed a new dural arteriovenous fistula fed by the anterior falcine artery and the middle meningeal artery to a cortical vein draining into the superior sagittal sinus. Conclusion: We hope that the present report will raise awareness to treating physicians to be cognizant of this unusual complication in their differential diagnosis when treating patients with an EVD in place.

Dural arteriovenous fistulas and headache features: an observational study

BACKGROUND

Dural arteriovenous fistulas are intracranial vascular malformations, fed by dural arteries and draining venous sinuses or meningeal veins. Clinical course varies widely and ranges from benign with spontaneous remission to fatal, due to cerebral hemorrhage. In a 10-year single institution experience, clinical presentation of dural arteriovenous fistulas, and in particular headache and angiographic features, as well as long-term outcome were analyzed.

METHODS

Data of 42 intracranial dural arteriovenous fistulas of 40 patients concerning demographic characteristics, medical history and risk factors, clinical presentation and headache features, location and neuroimaging findings, as well as treatment and outcome, were collected. Furthermore, we used the modified-Rankin Scale to assess the long-term outcome, by telephone contact with patients and/or their relatives.

RESULTS

Patients aged between 25 and 89 years (mean age 55.8 ± 15.5). According to different clinical presentation and evolution, related to their unique drainage pattern into the cavernous sinus, we examined the carotid-cavernous fistulas separately from other dural arteriovenous fistulas. Interestingly, we found that the migraine-like headache was the major onset symptom of dural arteriovenous fistulas different from carotid-cavernous fistulas (p = 0.036). On the other hand, non-migraine-like headache was a typical characteristic of carotid-cavernous fistulas (p = 0.003). Moreover, ocular symptoms were more frequently observed in carotid-cavernous fistulas (92.9% p < 0.001). Seventy percent of patients did not report any impact on quality of life (mRS 0 or 1) at follow-up.

CONCLUSIONS

These findings suggest a link between the site of lesion and clinical features of the headache, a symptom that usually leads to hospitalization. In particular, ocular symptoms accompanying non-migraine-like headache should be promptly recognized and raise the suspicion of a carotid-cavernous fistula, while migraine-like headache may suggests other dural arteriovenous fistulas. This study provides new significant insights on headache and its characteristics as a presentation symptom in dural arteriovenous fistulas.

Incidence of hereditary thrombophilia in patients with cranial dural arteriovenous fistulae

Dural arteriovenous fistulas (DAVFs) can develop as consequence of prior venous sinus thrombosis. However, the prevalence of prothrombotic conditions in patients with intracranial DAVFs is unknown and there is no consensus on the indications to screen for procoagulable conditions in these patients. We performed a retrospective review of patients presenting to our institution for management of cranial DAVF. Patient and DAVF characteristics were noted, in particular the incidence of hereditary thrombophilia (HT) detected by laboratory evaluation. Respective comparisons of patients with and without HT were performed using comparative statistics. There were 165 patients presenting for management of 171 DAVFs. A large proportion of DAVF were located at a large dural sinus (42.7%), which included superior sagittal, transverse, and sigmoid sinuses. On multivariate logistic regression analysis cortical venous drainage was independently associated with hemorrhagic presentation (OR 8.23, 95% CI 1.78-38.08; p = 0.007). A HT was detected in 18 of 61 patients (29.5%) who underwent a thrombophilia work-up. Location at a large dural sinus was not more common in patients with a HT (55.0% vs 54.5%; p = 0.97). There was also no difference in the presence of cortical venous drainage (56.5% vs 38.6%; p = 0.22) or hemorrhage on presentation (15.9% vs 5.0%; p = 0.22) in patients with and without a HT. In HT were found to be highly prevalent in our cohort, though our results do not suggest their presence greatly influences DAVF pathophysiology. Screening for procoagulable states is indicated in selected patients with an intracranial DAVF.