Dural arteriovenous fistula of the lateral foramen magnum region: A review

Surgical treatment of marginal sinus dural arteriovenous fistula: a narrative review

BACKGROUND

Dural arteriovenous fistulas of the marginal sinus (DAVFms) are uncommon and complex, with varied symptoms. Their complexity is heightened by the region's dense anastomotic network, posing risks for endovascular treatment. Surgical intervention can be effective, but this depends on thorough pre-operative understanding and optimal intra-operative visualization of the fistula.

OBJECTIVE

To review the relevant anatomy, presentation patterns of DAVFms, and provide insights for surgical treatment.

METHODS

Recent literature on DAVFms was reviewed, and three surgical cases are discussed to highlight treatment principles.

RESULTS

The symptoms of a DAVFms vary depending on its venous drainage pattern. Drainage may be either ascending towards the cranial compartment or descending towards the spinal canal. Patients suffering from DAVFms may experience hemorrhage, particularly when venous drainage is directed upwards. Congestive symptoms of the spinal cord or brainstem can occur in cases of downward venous drainage. Compared to the endovascular approach, open surgery has a higher success rate in obliterating the fistula and yields better outcomes in cases of perimedullary venous drainage. Achieving surgical success necessitates thorough preoperative evaluation and adequate surgical exposure. Brainstem hyperintensity observed on T2-weighted MRI scans is linked to a poorer prognosis for recovery.

CONCLUSION

Treating complex DAVFms often requires surgery, as endovascular methods may not be feasible. Successful surgery hinges on a precise understanding of the fistula's venous architecture and its spatial relationships, assessed using digital substraction angiography (DSA), angio-MRI, and angio-CT. Optimal intraoperative exposure is crucial for effective surgery.

Endovascular embolisation of posterior condylar canal dural arteriovenous fistula

We describe a rare case of dural arteriovenous fistula (dAVF) of the posterior condylar canal in a man in his 30s who presented with recent onset headache and neck pain and subsequently acute intracranial haemorrhage. Radiological workup showed a medulla bridging vein draining dAVF of the right posterior condylar canal supplied by a meningeal branch of the right occipital artery. A dilated venous sac was seen compressing over cerebellar tonsil on the right side. There was acute haemorrhage in the posterior fossa and fourth ventricle. He was successfully managed with transarterial endovascular embolisation via a supercompliant balloon microcatheter without any complication. The balloon microcatheter effectively prevented reflux of the liquid embolic agent into the parent artery and vasa nervosa of lower cranial nerves.

Treatment of high cervical arteriovenous fistulas in the craniocervical junction region

The craniocervical junction (CCJ) is a complex region. Rarely, arteriovenous fistulas (AVFs) can occur in the CCJ region. Currently, it is accepted that CCJ AVFs should only refer to AVFs at the C1-C2 levels. It is reasonable to assume that high cervical CCJ AVFs are being referred to when discussing CCJ AVFs. High cervical CCJ AVFs can be divided into the following four types: dural AVF, radicular AVF, epidural AVF and perimedullary AVF. Until now, it was difficult to understand high cervical CCJ AVFs and provide a proper treatment for them. Therefore, an updated review of high cervical CCJ AVFs is necessary. In this review, the following issues are discussed: the definition of high cervical CCJ AVFs, vessel anatomy of the CCJ region, angioarchitecture of high cervical CCJ AVFs, treatment options, prognoses and complications. Based on the review and our experience, we found that the four types of high cervical CCJ AVFs share similar clinical and imaging characteristics. Patients may present with intracranial hemorrhage or congestive myelopathy. Treatment, including open surgery and endovascular treatment (EVT), can be used for symptomatic AVFs. Most high cervical CCJ AVFs can be effectively treated with open surgery. EVT remains challenging due to a high rate of incomplete obliteration and complications, and it can only be performed in superselective AVFs with simple angioarchitecture. Appropriate treatment can lead to a good prognosis.

Transarterial embolization of dural arteriovenous fistula of the inferior petrosal sinus: A report of two cases

Dural arteriovenous fistula (DAVF) of the inferior petrosal sinus (IPS) is very unusual. Endovascular embolization is a good option for the treatment of DAVF. Until now, DAVFs of the IPS have only been reported sporadically. We reported two such cases. Case 1 was a 48-year-old man with headache and diplopia. Angiography confirmed a DAVF of the distal IPS, mainly supplied by the occipital artery (OA), and the IPS was occluded, which retrogradely drained into the cavernous sinus (CS) and then into the cortical vein. The DAVF in case 1 was embolized completely via the OA to cast Onyx-18. Case 2 was a 69-year-old female who had red and swollen eyes. Angiography confirmed a DAVF of the proximal IPS, mainly supplied by the accessory meningeal artery (AMA), which drained into the CS and then into the ophthalmic vein, and the IPS was occluded. The DAVF in case 2 was embolized completely via the AMA to cast Onyx-18. After treatment, these two patients had uneventful recoveries. In our report, these two cases indicated that the DAVFs of the proximal and distal IPS shared different origins of feeding arteries. When the IPS is occluded, the transarterial approach via the main feeder, such as OA and AMA, can be feasible to cure the DAVF of the IPS.

Intraoperative DSA-guided minimal approach for craniocervical junction DAVFs obliteration

BACKGROUND

Dural arteriovenous fistulas (DAVFs) are a group of diseases involving problematic shunts between dural arteries and venous structures such as sinuses, meningeal veins, or even cortical veins. To focus on craniocervical junction dural arteriovenous fistulas (DAVFs), we introduce a minimally invasive technique with midline incision combined with intraoperative digital subtraction angiography (DSA). This hybrid technique can minimize the incision wound to an average of 6 cm which leads to less destruction and lower risk of adverse events.

METHOD

Using this minimally invasive approach, surgical obliteration was achieved in 6 patients with craniocervical junction DAVFs. A minimal midline incision was made over the C1-2 level, measuring approximately 5 to 7 cm in length. C1 hemilaminectomy was performed for DAVF obliteration followed by intraoperative DSA for confirmation of complete obliteration.

RESULTS

Among these 6 patients, the radiculomedullary artery was the most common feeding artery. The mean length of the operation (including DSA performance) was 6.5 ± 1.4 h. None of these cases showed cerebrospinal fluid leakage or exacerbation of neurological symptoms after the operation.

CONCLUSION

Using intraoperative DSA, the minimally invasive technique offers more precise but less destructive access than conventional far lateral suboccipital craniotomy. Most importantly, intraoperative DSA provided verification of complete closure for shunts that could not be examined for indocyanine green (ICG) dye because the microscope did not have a clear line of sight. In our experience, this technique shows encouraging results of fistula obliteration.

Microsurgical Obliteration of Craniocervical Junction Dural Arteriovenous Fistulas: Multicenter Experience

BACKGROUND

Dural arteriovenous fistulas (dAVFs) located at craniocervical junction are extremely rare (1%-2% of intracranial/spinal dAVFs). Their angio-architectural complexity renders endovascular embolization to be challenging given multiple small feeders with risk of embolysate reflux into vertebral artery and limited transvenous access. The available literature discussing microsurgery for these lesions is limited to few case reports.

OBJECTIVE

To report a multicenter experience assessing microsurgery safety/efficacy.

METHODS

Prospectively maintained registries at 13 North American centers were queried to identify craniocervical junction dAVFs treated with microsurgery (2006-2021).

RESULTS

Thirty-eight patients (median age 59.5 years, 44.7% female patients) were included. The most common presentation was subarachnoid/intracranial hemorrhage (47.4%) and myelopathy (36.8%) (92.1% of lesions Cognard type III-V). Direct meningeal branches from V3/4 vertebral artery segments supplied 84.2% of lesions. All lesions failed (n = 5, 13.2%) or were deemed inaccessible/unsafe to endovascular treatment. Far lateral craniotomy was the most used approach (94.7%). Intraoperative angiogram was performed in 39.5% of the cases, with angiographic cure in 94.7% of cases (median imaging follow-up of 9.2 months) and retreatment rate of 5.3%. Favorable last follow-up modified Rankin Scale of 0 to 2 was recorded in 81.6% of the patients with procedural complications of 2.6%.

CONCLUSION

Craniocervical dAVFs represent rare entity of lesions presenting most commonly with hemorrhage or myelopathy because of venous congestion. Microsurgery using a far lateral approach provides robust exposure and visualization for these lesions and allows obliteration of the arterialized draining vein intradurally as close as possible to the fistula point. This approach was associated with a high rate of angiographic cure and favorable clinical outcomes.

Congestive myelopathy due to spinal dural arteriovenous fistula mimicking CNS demyelinating disease

Spinal dural arteriovenous fistula (SDAVF) is known for its ambiguous and various clinical presentations. Among these presentations, congestive myelopathy is one of the most common, yet it is challenging to correctly diagnose SDAVF at initial presentation. Several diseases present as myelopathy, including demyelinating diseases. Herein, we present two cases of congestive myelopathy due to SDAVF presenting to the emergency room (ER) with progressive quadriparesis. Even though the patients had a proper magnetic resonance imaging (MRI) examination from the initial presentation, there was a delay in making a final diagnosis. Both patients' clinical presentation and MRI mimicked central nervous system (CNS) demyelinating disease initially, and a more thorough examination revealed SDAVF. Such a delay in diagnosis can result in more neurological deterioration and may result in more sequelae. Hence, SDAVF should always be considered as a differential diagnosis when examining patients with myelopathy.

Endovascular treatment of medullary bridging vein-draining dural arteriovenous fistulas: foramen magnum vs. craniocervical junction lesions

PURPOSE

Dural arteriovenous fistulas (AVFs) draining to medullary bridging vein (MBV) are located at foramen magnum (FM) and craniocervical junction (CCJ). Such fistulas are rare but pose a challenge to endovascular management. This study was undertaken to assess clinical manifestations, angiographic features, and outcomes of endovascular treatment in patients with MBV dural AVFs.

METHODS

A number of our patients (N = 22) were diagnosed with MBV dural AVF and treated by endovascular means. There were 9 FM lesions and 13 CCJ lesions. We reviewed clinical records and imaging studies to define clinical characteristics, vascular anatomic details, and treatment outcomes, comparing FM- and CCJ-level subsets.

RESULTS

Subjects ranged from 37 to 74 years of age (mean, 57.7 years) with male predominance (2.7:1). They presented with intracranial hemorrhage (11/22, 50%), myelopathy (8/22, 36%), or nonspecific symptoms (3/22, 14%). In 17 patients (77.3%), the shunts showed complete or near-complete occlusion following endovascular treatment (FM, 100%; CCJ, 61.5%). However, seven patients experienced ischemic events (FM, 11.1%; CCJ, 46.2%) and one patient sustained a hemorrhagic complication. No hemorrhages recurred during follow-up monitoring, and myelopathic symptoms abated.

CONCLUSION

MBV dural AVFs are highly aggressive lesions for which proper diagnosis and treatment are of utmost importance. Although transarterial embolization proved highly successful in FM lesions, shunt occlusion was less frequent in the CCJ subset, with greater risk of ischemic complications.

Foramen Magnum Dural Arteriovenous Fistula Presenting With Thoracic Myelopathy: Technical Case Report With 2-Dimensional Operative Video

BACKGROUND AND IMPORTANCE

Dural arteriovenous fistulas (dAVFs) are vascular abnormalities of the central nervous system that can cause a wide array of neurological dysfunction depending on their location, flow, and propensity to rupture. Symptomatic dAVFs at the cranio-cervical junction usually result in hemorrhage or cervical myelopathy. Distantly located dAVFs of the foramen magnum are a rare cause of thoracic intrinsic myelopathy.

CLINICAL PRESENTATION

An 83-yr-old man presented with progressive lower extremity weakness, numbness, and difficulty walking along with episodes of bowel incontinence. Magnetic resonance imaging of the cervical spine demonstrated multilevel cervical disc disease with stenosis and longitudinal cervical cord signal change extending into the upper thoracic spinal cord. Cerebral and spinal angiography revealed a dAVF in the lateral foramen magnum region. Given the location, feeding vasculature, and morphology of the fistula, endovascular embolization was not attempted. Microsurgical resection with confirmative indocyanine green fluorescent imaging was performed with adequate obliteration of the fistula. The patient's neurological baseline was preserved postoperatively with improvement of lower extremity numbness.

CONCLUSION

We present a brief overview of this neuropathologic entity and demonstrate microsurgical resection of a foramen magnum dAVF through operative video. Craniocervical dAVFs should remain on the differential diagnosis of patients presenting with progressive thoracolumbar myelopathy.

Endovascular treatment strategy, technique, and outcomes for dural arteriovenous fistulas of the marginal sinus region

BACKGROUND

Dural arteriovenous fistulas (AVF) of the foramen magnum region (FMR) are technically challenging lesions to treat. Transvenous (TV), transarterial (TA), and surgical approaches have been described, but the optimum treatment strategy is not defined.

OBJECTIVE

To report treatment strategies and outcomes for FMR-AVF at a single, high-volume referral center.

METHODS

A retrospective review from January 2010 to August 2020 identified patients with FMR-AVF at a single referral center. Angiographic features, treatment (observation, endovascular, surgical), and follow-up of angiographic and clinical results were recorded. The technical aspects of TV embolization are then presented in detail.

RESULTS

29 FMR-AVF were identified in 28 patients. Of these, 24/29 (82.8%) were treated and 5/29 (17.2%) were observed. Treatment was endovascular in 21/24 (87.5%), combined (endovascular+surgical) in 2/24 (8.3%), and surgical in 1/24 (4.2%). Endovascular treatments were 76.2% TV, 14.3% TA, and 9.5% combined TV/TA. Sufficient follow-up data were available for 20/28 (71.4%) with mean follow-up of 16.8 months. No AVF recurrence was seen for TA/TV, combined endovascular/surgical, or surgical groups, and there was one recurrence (7.1%) in the TV group. Symptomatic improvement was seen in all groups: TV (71.4% complete, 28.6% partial), TA (66.7% complete, 33.3% no follow-up), TV+TA (100% partial), endovascular/surgical (100% complete), and surgical (100% partial). Minor non-neurologic complications included 1/14 (7.1%) in the TV group and 1/3 (33.3%) in the TA/TV group.

CONCLUSION

Endovascular treatment is safe and effective for most FMR-AVF. TV embolization has a high cure rate with few complications.

[Vascular malformations of the head and neck]

Vascular malformations are congenital anomalies of the vascular system that often affect the head and neck region. Vascular malformations are typically present at birth and proportionately grow with the patient. In contrast to vascular tumors, they are composed of dysplastic vessels rather than proliferating cells. The most commonly used classification is that of the International Society for the Study of Vascular Anomalies (ISSVA). According to this classification, simple malformations include venous, capillary, lymphatic, arteriovenous malformations, and arteriovenous fistulas. Symptoms depend on the affected anatomical structures and can range from swelling to life-threatening bleeding, airway obstruction or blindness. Management options for vascular malformations include conservative approaches, surgical intervention, sclerotherapy and embolisation as determined by type of malformation, location and associated complications. This article provides an overview of the major types of vascular malformations that affect the head and neck.

Transvenous embolization of a posterior condylar canal fistula causing pulsatile tinnitus

Dural arteriovenous fistulas of the skull base commonly present with pulsatile tinnitus. In our experience, transvenous embolization of dural arteriovenous fistulas of the skull base represents a safe and effective treatment modality due to its precision in treatment of the site of convergence of all feeding arteries and the low risk of ischemic complications. We present a case of an adult patient who presented to our institution with pulsatile tinnitus several months following a motor vehicle accident. Cerebral angiography demonstrated a dural arteriovenous fistula at the junction of the posterior condylar vein and suboccipital venous plexus supplied by branches of the vertebral artery, occipital artery, and ascending pharyngeal artery. In this operative video we demonstrate this technique and provide an in-depth discussion of our treatment decision-making process and the anatomical considerations involved in treating this lesion.

Clinical importance of the superficial temporal artery in neurovascular diseases: A PRISMA-compliant systematic review

The superficial temporal artery (STA) plays a very important role in neurovascular diseases and procedures. However, until now, no comprehensive review of the role of STA in neurovascular diseases from a neurosurgical perspective has ever been published. To review research on the clinical importance of STA in neurovascular diseases, a literature search was performed using the PubMed database. Articles were screened for suitability and data relevance. This paper was organized following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. According to the literature, STA is one of the terminal branches of the external carotid artery and can give off scalp, muscle, and transosseous branches. STA-middle cerebral artery (MCA) bypass is very useful for intracranial ischemic diseases, including moyamoya disease, chronic ICA and MCA insufficiency, and even acute ischemic stroke. For intracranial complex aneurysms, STA bypass remains a major option that can serve as flow replacement bypass during aneurysmal trapping or insurance bypass during temporary parent artery occlusion. Occasionally, the STA can also be involved in dural AVFs (DAVFs) via to its transosseous branches. In addition, the STA can be used as an intraoperative angiography path and the path to provide endovascular treatments. Therefore, STA is a very important artery in neurovascular diseases.