Natural history and treatment of craniocervical junction dural arteriovenous fistulas

Transarterial embolization of radicular arteriovenous fistula at the craniocervical junction

Craniocervical junction arteriovenous fistula (CCJ AVF) is a rare vascular disorder. Direct surgery for CCJ AVF is generally reported to have better outcome compared to endovascular treatment. However, no certain consensus has been obtained so far. We report a case of radicular CCJ AVF treated by transarterial embolization that resulted in a good outcome. A 69-year-old man presented with subarachnoid hemorrhage primarily in the posterior cranial fossa. Based on digital subtraction angiography showed radicular CCJ AVF with varix. Transarterial embolization was performed with n-butyl-2-cyanoacrylate on day 17 after onset and successfully cured. The neurovascular anatomy of CCJ AVF is complicated, but endovascular treatment may be a treatment option with detailed understanding of angioarchitecture and selective endovascular procedure.

Clinical features, treatment strategies and outcomes of craniocervical junction arteriovenous fistulas: a cohort study of 193 patients

BACKGROUND

Craniocervical junction (CCJ) arteriovenous fistulas (AVFs) are rare. The current treatment strategies for AVFs with different angioarchitecture need to be clarified. The present study aimed to analyse the correlation between angioarchitecture and clinical characteristics, share our experience in treating this disease and identify risk factors associated with subarachnoid haemorrhage (SAH) and poor outcomes.

METHODS

A total of 198 consecutive patients with CCJ AVFs from our neurosurgical centre were retrospectively reviewed. The patients were grouped according to their clinical manifestations, and their baseline clinical characteristics, angioarchitecture, treatment strategies and outcomes were summarised.

RESULTS

The patients' median age was 56 years (IQR 47-62 years). The majority of patients were men with 166 (83.8%) patients. The most common clinical manifestation was SAH (52.0%), followed by venous hypertensive myelopathy (VHM) (45.5%). The most common CCJ AVFs type was dural AVF, with 132 (63.5%) fistulas. The most frequent fistula location was C-1 (68.7%) and dural branch of vertebral artery (70.2%) was the most involved arterial feeders for fistulas. The most common direction of venous drainage was descending intradural drainage (40.9%), followed by ascending intradural drainage (36.5%). Microsurgery was the most common treatment strategy applied for 151 (76.3%) patients, 15 (7.6%) patients were treated with interventional embolisation only, and 27 (13.6%) received both interventional embolisation and microsurgical treatment. The learning curve for microsurgery only was analysed by cumulative summation method, and the turning point was the 70th case, and blood loss in post-group was lower than that in pre-group (p=0.034). At the last follow-up, there were 155 (78.3%) patients with favourable outcomes (modified Rankin Scale(mRS)<3). Age≥56 (OR 2.038, 95% CI 1.039 to 3.998, p=0.038), VHM as the clinical manifestation (OR 4.102, 95% CI 2.108 to 7.982, p<0.001) and pretreatment mRS≥3 (OR 3.127, 95% CI 1.617 to 6.047, p<0.001) were significantly associated with poor outcomes.

CONCLUSION

The arterial feeders and direction of the venous drainage were important factors in the clinical presentations. The location of fistula and drainage vein was essential for choosing different treatment strategies. Older age, VHM onset and poor pretreatment functional status predicted poor outcomes.

Enhanced Treatment Options for Dural Arteriovenous Fistulas at the Craniocervical Junction: Endovascular Embolization Versus Microsurgery? A Single-Center 23-Year Experience

OBJECTIVE

The occurrence of dural arteriovenous fistulas (DAVFs) at the craniocervical junction (CCJ) is an uncommon vascular malformation. The diagnosis and treatment of CCJ DAVFs present a formidable challenge. This study aims to investigate the effect of endovascular embolization and microsurgery on improving patient prognosis.

METHODS

This retrospective study included patients diagnosed with CCJ DAVFs who received treatment at the First Affiliated Hospital of Fujian Medical University between January 2000 and January 2023. The clinical records, imaging data, and treatment methods were obtained from the hospital's medical record system. The patients were classified into microsurgery and embolization groups based on the surgical technique employed for treatment. The primary outcome measures were surgical-associated neurological dysfunction (SAND) and long-term neurological outcomes. The Cox proportional hazard regression was utilized to determine hazard ratios and 95% confidence intervals (CI) to assess the relationship between treatment methods and prognosis. Kaplan-Meier survival analysis was employed to evaluate the incidence of SAND in both cohorts.

RESULTS

This study recruited 46 patients with an average age of 53.72 ± 13.83 years. In the microsurgery group, there were 12 cases (26.1%) observed. While in the embolization group, there were 34 cases (73.9%). Of these patients, 16 (34.8%) experienced SAND after treatment. In the microsurgery group, there were 8 cases (75.0%), while in the embolization group, only 8 cases (23.5%) were reported. Specifically, the embolization group exhibited a significantly lower risk of SAND [adjusted hazard ratio = 0.259, 95% CI = 0.096-0.700; P = 0.008)] compared to the microsurgery group. Additionally, the combined Borden grade 2-3 was found to be significantly associated with SAND (adjusted hazard ratio = 3.150, 95% CI = 1.132-8.766; P = 0.028). The results of the Kaplan-Meier survival analysis indicated a statistically significant difference in the occurrence of favorable functional outcomes between the 2 groups (log-rank P = 0.0081).

CONCLUSIONS

CCJ DAVFs are uncommon disorders characterized by a diverse range of clinical manifestations. The functional prognosis of endovascular treatment may be superior to microsurgery.

Craniocervical dural arteriovenous fistula: Microsurgical clipping and technical nuances with ICG

A 48-year-old male with progressive congestive myelopathy had a craniocvervical DAVF treated with surgical clipping using ICG to confirm solitary inflow.

Craniocervical Junction Dural Arteriovenous Fistula and Pial Arteriovenous Fistula Presenting Concomitantly in Separate Locations with Subarachnoid Hemorrhage

Craniocervical junction dural arteriovenous fistula and pial arteriovenous fistula are rare cerebrovascular lesions. While their pathophysiology is different, both conditions can cause intracranial hemorrhage attributable to venous congestion. We present, to our knowledge, the first case report of craniocervical junction dural arteriovenous fistula and pial arteriovenous fistula presenting concomitantly in separate locations with subarachnoid hemorrhage. This case appears to have been due to increased venous hypertension caused by a merging of the venous drainage of the 2 lesions, resulting in hemorrhage.

Intramedullary feeder aneurysm of a cervical epidural arteriovenous fistula causing myelopathy: a case report and literature review

While a craniocervical junction (CCJ) epidural arteriovenous fistula (EDAVF) may present with hemorrhagic myelopathy from an associated feeder aneurysm on rare occasions, non-hemorrhagic myelopathy from such an aneurysm remains unreported. A woman in her late sixties presented with cervical myelopathy due to a non-hemorrhagic intramedullary aneurysm associated with CCJ-EDAVF. The intramedullary aneurysm originated from the spinal pial artery supplied by the anterior spinal artery. Direct surgical fistula coagulation and feeder obliteration resulted in the disappearance of the aneurysm and myelopathy improvement. This report illustrates the first case of a non-hemorrhagic intramedullary aneurysm associated with CCJ-EDAVF successfully treated with direct surgery.

Spinal Dorsal Intradural Arteriovenous Fistulas: Natural History, Imaging, and Management

In this review, we describe the pathophysiology, diagnosis, and treatment of spinal dorsal intradural arteriovenous fistulas (DI-AVFs), focusing on novel research areas. DI-AVFs compose the most common subgroup of spinal arteriovenous lesions and most commonly involve the thoracic spine, followed by lumbar and sacral segments. The pathogenesis underlying DI-AVFs is an area of emerging understanding, thought to be attributable to venous congestion and hypertension that precipitate ascending myelopathy. Patients with DI-AVFs typically present with motor, sensory, or urinary dysfunction, although a wide swath of other less common symptoms has been reported. DI-AVFs can be subdivided by spinal region, which in turn is associated with 4 distinct clinical phenotypes: craniocervical junction (CCJ), subaxial cervical, thoracic, and lumbosacral. Patients with CCJ and lumbosacral DI-AVFs have particularly interesting presentations and treatment considerations. High-value diagnostic findings on MRI include flow voids, missing-piece sign, and T2-weighted intramedullary hyperintensity. However, digital subtraction angiography is the gold standard for diagnosis and localization of DI-AVFs and for definitive treatment planning. Surgical disconnection of DI-AVFs is almost universally curative and frontline treatment, especially for CCJ and lumbosacral DI-AVFs. Endovascular techniques evolve in promising ways, such as improved visualization, distal access, and liquid embolic techniques. The pathophysiology of DI-AVFs is better understood using newly identified radiologic diagnostic markers. Despite new techniques and devices introduced in the endovascular field, surgery remains the gold-standard treatment for DI-AVFs.

FLOW-diverted Glue Embolization to Target lesions (FLOW-GET) technique for spinal vascular diseases: A technical note

We present and exemplify the flow-diverted glue embolization to target lesions (FLOW-GET) technique for spinal vascular diseases. In this technique, the occlusion of the posterior intercostal artery or dorsal muscular branch by coils diverts the injected glue from the segmental artery to the target lesions. This technique was applied to a ruptured retrocorporeal artery aneurysm and spinal dural arteriovenous fistulas. The FLOW-GET accomplished the complete obliteration of all lesions. This simple and useful technique can be applied to spinal vascular lesions even if a microcatheter is not placed in proper feeders or advanced close to the shunt points or aneurysms.

Surgical and Endovascular Treatments for Asymptomatic Arteriovenous Fistulas at the Craniocervical Junction: A Multicenter Study

OBJECTIVE

Asymptomatic craniocervical junction arteriovenous fistulas (CCJ AVFs) are rare and, thus, a consensus has not yet been reached regarding the indication of surgical interventions. This retrospective multicenter cohort study investigated the risks associated with surgery for asymptomatic CCJ AVFs and discussed the indication of surgical interventions.

METHODS

Using data from 111 consecutive patients with CCJ AVFs registered with the Neurospinal Society of Japan between 2009 and 2019, we analyzed the treatment, complications, and outcomes of 18 patients with asymptomatic CCJ AVF.

RESULTS

The median age of the patient cohort was 68 years (37-80 years), and there were 11 males and 7 females. Diagnoses were 14 patients with dural AVF, one perimedullary AVF, one radicular AVF, one epidural AVF, and one bilateral dural and epidural AVF. Initial treatment included direct surgery in 12 patients, endovascular treatment in four, and conservative treatment in two. Among 16 patients, three complications (18.7%) occurred: spinal cord infarction associated with the surgical procedure, cerebral infarction associated with intraoperative angiography, and mortal medullary hemorrhage after endovascular treatment followed by open surgery. Complete occlusion was achieved in all 12 patients in the direct surgery group and in one out of four in the endovascular treatment group.

CONCLUSIONS

Given the risk of serious complications associated with asymptomatic CCJ AVF and the fact that no case of asymptomatic CCJ AVF became symptomatic in this study, prophylactic surgery for asymptomatic CCJ AVF should be carefully considered.

Treatment of Dural Arteriovenous Fistula with Intradural Draining Vein at the Craniocervical Junction: Case Series with Special Reference to the Anatomical Considerations

BACKGROUND

Dural arteriovenous fistulas at the craniocervical junction (CCJ DAVFs) are a rare vascular disease. Endovascular treatment (EVT) and microsurgery are the primary treatment modalities for CCJ DAVFs. However, incomplete treatment or complications may occur after treatment because of the anatomical complexity.

OBJECTIVE

We analyzed the neurosurgical treatment experiences of CCJ DAVFs to recommend suitable classification and treatment options.

METHODS

CCJ DAVFs were anatomically classified into three types according to the feeding arteries and their relationships with the anterior spinal (ASAs) and lateral spinal arteries (LSAs). Type 1 was fed by the radiculomeningeal artery from the vertebral artery and was not associated with the ASA or LSA. Type 2 was fed by the radiculomeningeal artery, and the radicular artery supplied the LSA near the fistula point. Type 3 had the characteristics of type 1 or type 2 CCJ DAVFs, except the ASA also contributed to the fistula.

RESULTS

There were 5, 7, and 4 cases of type 1, type 2, and type 3 CCJ DAVFs, respectively. EVT was attempted in 12 patients, of whom only 1 (type 1) was completely cured without complications. Nine cases had residual lesions after EVT, and two had spinal cord infarction due to occlusion of the LSA. Fourteen patients underwent microsurgical treatment. In all 14 cases, CCJ DAVFs were completely obliterated after microsurgery.

CONCLUSION

In cases of type 1 CCJ DAVF, both microsurgical treatment and EVT may be considered. However, for type 2 and 3 CCJ DAVFs, microsurgery may be a superior treatment modality.

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.

Angioarchitectural features of arteriovenous fistulas at craniocervical junction predicting clinical presentation and unfavorable neurological function: insight from a multicenter cohort and pooled analysis

Arteriovenous fistulas (AVFs) at the craniocervical junction (CCJ) are uncommon conditions with complex angioarchitecture. The objective of this study was to identify the angioarchitectural features of CCJ-AVF that were predictive of clinical presentation and neurological function. The study encompassed a total of 68 consecutive patients with CCJ-AVF at two neurosurgical centers between 2014 and 2022. Additionally, a systematic review was conducted, including 68 cases with detailed clinical data obtained via PubMed database spanning 1990 to 2022. Clinical and imaging data were collected and pooled together to analyze factors associated with subarachnoid hemorrhage (SAH), myelopathy, and modified Rankin scale (mRS) at presentation. The mean age of the patients was 54.5 ± 13.1 years, with 76.5% of them being male. The most common feeding arteries were V3-medial branches (33.1%), and drainage was frequently through the anterior or posterior spinal vein/perimedullary vein (72.8%). SAH was the most common presentation (49.3%), and an associated aneurysm was identified as a risk factor for SAH (adjusted OR, 7.44; 95%CI, 2.89-19.15). Anterior or posterior spinal vein/perimedullary vein (adjusted OR, 2.78; 95%CI, 1.00-7.72) and male gender (adjusted OR, 3.76; 95%CI, 1.23-11.53) were associated with higher risk for myelopathy. Myelopathy at presentation was an independent risk factor for unfavorable neurological status (adjusted OR per score, 4.73; 95%CI, 1.31-17.12) in untreated CCJ-AVF. The present study identifies risk factors associated with SAH, myelopathy, and unfavorable neurological status at presentation in patients with CCJ-AVF. These findings may help treatment decisions for these complex vascular malformations.

Functional Vascular Anatomy and Arteriovenous Shunts of the Spine

The history of vascular anatomy of the spinal cord and spine began in the late 19th century. With recent advances in endovascular and surgical treatment of vascular lesions of the spinal cord, understanding the vascular anatomy of the spinal cord has become more important than ever. Catheter angiography is the gold standard for diagnosing vascular lesions of the spinal cord, and the vascular architecture of the spinal cord itself is relatively simple, a repetition of basic longitudinal and axial structures. This review discusses the vascular anatomy of the spine and spinal cord from the embryological point of view, as well as an overview of typical spinal arteriovenous shunt diseases mainly depending on their locations: paraspinal, epidural, dural, perimedullary, intramedullary, filum terminale/cauda equina, craniocervical junction, and related diseases.

Intraoperative identification of the lateral spinal artery in a case of craniocervical junction dural arteriovenous fistula surgically obliterated

BACKGROUND

The formation of a dural arteriovenous fistula (DAVF) at the craniocervical junction is rare. Such a fistula can be fed by the branches of the vertebral and external carotid arteries. The lateral spinal artery can branch from the vertebral artery. The feeders of a DAVF at the craniocervical junction are often diagnosed on preoperative angiography, and there is little reported evidence on the intraoperative diagnosis of the lateral spinal artery.

CASE DESCRIPTION

An 84-year-old man presented with motor weakness and sensory disturbance of the lower extremities. Edematous changes in the medulla oblongata and cervical spinal cord were observed on magnetic resonance imaging. Cerebral angiography revealed a DAVF fed by a branch of the vertebral artery, with a shunting point located in the dura of the right condyle; the main drain was the anterior spinal vein. The DAVF drain was surgically obliterated to prevent hemorrhagic events and improve neurological symptoms. Intraoperatively, an artery branching from the feeder of the DAVF was identified and preserved. The patient had a good postoperative course, and the neurological symptoms were ameliorated. Follow-up cerebral angiography revealed proximal branching of the lateral spinal artery from the feeding artery of the DAVF.

CONCLUSION

A lateral spinal artery was identified intraoperatively while a DAVF at the craniocervical junction was obliterated. This suggests that preoperative imaging should be carefully reviewed, and endovascular procedures should consider such possibilities to avoid adverse ischemic outcomes.

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.

The role of venous anatomy in guiding treatment approach for dural arteriovenous fistulas of the craniocervical junction; case series & systematic review

BACKGROUND

Dural arteriovenous fistulas (DAVF) of the craniocervical junction (CCF) are an uncommon entity with the following venous drainage pattern: inferior, superior and mixed. Patients may present with subarachnoid hemorrhage, myelopathy or brainstem dysfunction. CCJ DAVF can be treated with microsurgery or with transarterial and transvenous embolization, depending on the venous drainage pattern. We present our institutional experience of treating CCJ DAVFs along with a systematic review of the literature.

METHODS

Six patients with CCJ DAVF were treated at our institution over five years. Data was collected using electronic medical record review. Systematic review was performed on CCJ DAVF using the PubMed database from 1990 to 2021. We characterized venous drainage patterns, treatment choices, and outcomes to create a classification system.

RESULTS

50 case reports, consisting of 115 patients, were included in our review. 61 (53.0 %) patients had inferior drainage while 32 (27.8 %) patients had superior drainage and 22 (19.2 %) patients had mixed venous drainage. Patients with inferior drainage had the fistulous connection at the foramen magnum while patients with superior drainage had a fistulous connection at C1-C2 (p value = 0.026). Patients with inferior drainage were more likely to present with myelopathy while patients with superior drainage presented with hemorrhage (p value = 0.000).

CONCLUSIONS

Classifying the venous drainage pattern is essential in making treatment decision. Transvenous embolization works best with large superior venous drainage. If endovascular treatment is not an option, then surgical clipping can achieve successful cure. Transarterial embolization is a reasonable option in cases with a large arterial feeder.

Unique vascular structures of a radicular arteriovenous fistula at the craniocervical junction along the first cervical spinal nerve: A case report

Background:

An arteriovenous fistula (AVF) at the craniocervical junction (CCJ) is a rare vascular malformation. Definitive diagnosis and curative treatment of CCJ AVF are challenging.

Case Description:

A 77-year-old man presented with subarachnoid hemorrhage. Cerebral angiography showed an AVF at the CCJ, which drained into a radicular vein. The lesion was fed by a vertebral artery, anterior and lateral spinal arteries (LSAs), and the occipital artery (OA). There were two unique structures: the LSA originating from the posterior inferior cerebellar artery of the extracranial V3 segment and the OA feeding the shunt. Curative treatment involved two steps: endovascular embolization of feeders using Onyx and surgical shunt disconnection. Feeding arteries were blackened by Onyx, which helped identify the location of the shunt. The shunt was located behind the first cervical (C1) spinal nerve, and the draining vein was confirmed on the deep side of the nerve. A clip was applied to the draining vein distal to the shunt. Tiny vessels supplying the shunt were then coagulated referring to blackened arteries.

Conclusion:

A radicular AVF at the CCJ along the C1 spinal nerve had unique vascular structures. Definitive diagnosis and curative treatment were achieved by combining endovascular embolization using Onyx and direct surgery.

Congestive myelopathy due to craniocervical junction arteriovenous fistulas mimicking transverse myelitis: a multicenter study on 27 cases

BACKGROUND

The purpose was to clarify diagnostic clues and pitfalls in cranio-cervical junction arteriovenous fistulas (CCJ AVFs) with congestive myelopathy.

METHODS

In a multicenter observational study by the Neurospinal Society of Japan, we described the demographics, clinical courses, imaging findings, and outcomes of consecutive patients with CCJ AVFs presenting with congestive myelopathy between 2009 and 2019.

RESULTS

Twenty-seven patients were included (mean age, 70 years; male, 96%). Progressive symptoms within one day to one month were more common (63%) than chronic symptoms. Myelopathic symptoms were characterized by ascending paralysis beginning from the legs, involving the trunk and arms, and sometimes ending in the brainstem. Fifteen patients (56%) received a misdiagnosis, including acute transverse myelitis. The most common MRI findings were venous congestive edema of the cervical cord (96%) and the brainstem (63%) and surrounding vascular flow voids (100%). The mean extension of congestive edema was 5.5 ± 2.9 vertebral segments. The most common angiographic findings were a dural AVF (78%) at the C1 level (81%) with descending venous drainage (85%). Seven patients (26%) were administered steroids, which resulted in neurological decline in 3. Neurosurgical obliteration of the AVF led to improvements in MRI findings in 75% and a functional status in 67%; however, 44% remained dependent.

CONCLUSIONS

The myelopathy of CCJ AVFs was characterized by acute ascending paralysis in elderly men. A misdiagnosis was common because of the acute presentation due to a longitudinally extensive spinal cord lesion. Dilated vessels on MRI were a key finding for the correct diagnosis. What is already known on this topic? Slowly progressive myelopathy is a well-known symptom that results from impaired spinal venous drainage due to thoracolumbar AVFs. Although cranio-cervical junction arteriovenous fistulas (CCJ AVFs) constitute a treatable cause of congestive myelopathy, detailed information is not currently available due to their rarity. What does this study add? CCJ AVFs often presented with acute ascending myelopathy in elderly men due to a longitudinally extending cervical cord lesion with surrounding flow voids. Steroid pulse therapy was not effective or even harmful to congestive myelopathy, while neurosurgical treatment effectively obliterated AVFs. How might this study affect research, practice or policy? The results obtained revealed diagnostic clues and pitfalls from the largest dataset of patients with CCJ AVFs in a multicenter cohort.

A case of craniocervical junction pial arteriovenous fistula causing postoperative medullary and spinal cord edema

OBJECTIVES

Pial arteriovenous fistulas (pAVFs) are direct connections between the pial artery and vein without an intervening nidus. We report a rare case of craniocervical junction (CCJ) pAVF causing medullary and spinal cord edema resulting from surgical removal of the varix with remnant shunt after coil embolization.

CASE DESCRIPTION

A 16-year-old man presented with subarachnoid hemorrhage. Digital subtraction angiography revealed a CCJ pAVF with multiple fistulas at the 2 varices (varix A and varix B), which was fed by the bilateral lateral spinal arteries and anterior spinal artery (ASA), and drained into the median posterior vermian vein with varix (varix C) and anterior spinal vein (ASV). Varices A and B were embolized using coils, but the shunts remained in varix C. Then, varix C was surgically removed. After this operation, medullary and spinal cord edema occurred. Digital subtraction angiography showed the ASV drainage responsible for edema. Finally, surgical removal of varices A and B was performed. However, arteriovenous shunts, supplied by the ASA and drained into the ASV via the intrinsic vein, were found in the medulla oblongata and coagulated, resulting in disappearance of edema.

CONCLUSIONS

Edema was probably caused by concentration of drainage from the arteriovenous shunt in the medulla oblongata into the ASV by surgical removal of varix C acting as another draining route. High flow AVF can induce angiogenesis and secondary arteriovenous shunt. Precise analysis of the angioarchitecture is important to treat such cases without complications.

Arteriovenous fistulas in the craniocervical junction region: With vs. without spinal arterial feeders

Objective

Arteriovenous fistulas (AVFs) in the craniocervical junction (CCJ) region are a rare occurrence with special clinical manifestations. This study retrospectively reviewed patients with CCJ AVFs treated at our neurosurgical center, aiming to enhance the understanding of CCJ AVFs.

Methods

A total of 113 patients with CCJ AVFs treated at our neurosurgical center between January 2013 and December 2020 were enrolled. They were grouped as patients with CCJ AVFs with spinal arterial feeders (n = 20) and patients with CCJ AVF without spinal arterial feeders (n = 93). Clinical presentation, angiographic characteristics, intraoperative findings, and treatment outcomes were analyzed.

Results

The patients' median age was 55 years (IQR 47.5-62 years). The proportion of males in the group without spinal arterial feeders was significantly higher (p = 0.001). Subarachnoid hemorrhage (SAH) was the most common clinical presentation, especially in the group with spinal arterial feeders (p < 0.001). There were significant differences in AVF type, fistula location, and direction of the venous drainage between the two groups (p < 0.001). Intervention embolization combined with microsurgery was more common in treating AVFs with spinal arterial feeders (p = 0.006). Spinal arterial feeders did not affect the outcome (p = 0.275).

Conclusions

SAH was the most common presentation of CCJ AVFs in this study. Microsurgery and interventional embolization were optional treatment strategies. The angioarchitecture of CCJ AVFs was essential for selecting treatment strategies.

Thoracolumbar spinal dural arteriovenous fistulae present with longer arteriovenous transit compared to cranial and cervical dural fistulae

BACKGROUND

Thoraco-lumbar spinal dural arteriovenous fistulae represent a rare subset of central nervous system vascular malformations. One of the unique features of spinal dural arteriovenous fistulae is their extremely low propensity to cause hemorrhage (either parenchymal or subarachnoid), with a distinct clinical presentation of myelopathy secondary to spinal venous congestion. The exact mechanism for this unique presentation is still unclear.

METHODS

Following institutional review board approval, we retrospectively analyzed our prospectively maintained database of spinal dural arteriovenous fistulae and cranial (cr) DAVF cases presenting between 2008 and 2021. For all cases, angiograms were reviewed and arteriovenous transit times were calculated. Patient demographics, angiographic features, and clinical and radiological outcomes were assessed.

RESULTS

In total, 66 patients presenting with confirmed thoracolumbar spinal dural arteriovenous fistulaes were identified and compared to patients presenting with cervical spinal dural arteriovenous fistulaes (n  =  10), ruptured crDAVFs (n  =  32) and unruptured crDAVFs (n  =  20). Mean age in the target group was 66  ±  13 versus 57-62 in the other groups, p < 0.05 on one-way analysis of variance; with 80% males versus 50%-65% in other groups. Mean arteriovenous transit time in the thoracolumbar group measured 1.98 s ± 0.96 versus 0.25-0.5 s range in other groups (p < 0.0001 on one-way analysis of variance).

CONCLUSION

Prolonged arteriovenous transit times may represent a distinct feature of thoracolumbar spinal dural arteriovenous fistulaes. This may, amongst other factors, play a role in the observed lesser likelihood of hemorrhagic complications compared to other dural arteriovenous shunts.

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.

Far lateral craniotomy for disconnection of vertebral dural arteriovenous fistula: how I do it

BACKGROUND

Craniocervical junction (CCJ) vascular abnormalities can be challenging to treat because of the surrounding density of critical neurovascular anatomy. Although most dural arteriovenous fistulas (dAVFs) are now treated with endovascular surgery, dAVFs near the CCJ are often better suited for microsurgical obliteration with precise vascular control.

METHODS

We describe our microsurgical approach to treating dAVFs at the CCJ. This includes a far-lateral approach with a small incision centered over the transverse process of the atlas and circumferential skeletonization of the vertebral artery in addition to clipping the fistula to limit lesion recurrence.

CONCLUSIONS

Definitive microsurgical treatment of CCJ dAVFs can be accomplished using a minimally invasive approach.

Dural arteriovenous fistula of the craniocervical junction along the first cervical nerve: A single-center experience and review of the literature

BACKGROUND

Dural arteriovenous fistulas (DAVFs) of the craniocervical junction (CCJ) are relative rare lesions. Most studies of DAVFs of the CCJ included the fistulas at the foramen magnum, first cervical (C1), and second cervical (C2) level. DAVFs of the CCJ along C1 spinal nerve are rare vascular lesions with distinctive features. Our aim is to review cases of DAVFs of the CCJ along C1 spinal nerve at our institution.

METHODS

From June 2008 and December 2021. We reviewed a consecutive series of intracranial and spinal DAVFs at our institution and collected all patients harboring DAVFs of the CCJ along C1 spinal nerve. Medical charts were retrospectively reviewed regarding patient demographic data (i.e., gender and age), presenting symptoms and signs, treatment methods, and neurological outcome and complications after treatment. All image studies, including cranial computed tomography (CT) scan, cervical magnetic resonance imaging, CT angiography, and digital subtraction angiography (DSA) with rotational CT angiography were analyzed by experienced neuroradiologists. The authors also review of the literature of DAVFs of the C1 spinal nerve.

RESULTS

The authors identified 7 patients, including 5 men (71.4 %) and 2 women (28.6 %) with median age 54 years, range 48-72 years. Subarachnoid hemorrhage (SAH) occurred in 5 (71.4 %) patients, and progressive myelopathy in 2 (28.6 %). All fistulas except one received blood supply from the radiculomeningeal branch of the VA at C1 level. Venous aneurysms, being the source of bleeding, were detected in all fistulas with SAH. All patients except one were treated by surgical management. One fistula was treated by balloon-assisted Onyx embolization. Most patients had good neurological outcome following surgery. Complete obliteration of all fistulas treated by surgery was confirmed by follow-up DSA obtained 1 week after surgery. Two patients developed temporary pain and spasm of the trapezius muscle after the surgery. One patient resulted in poor neurological outcome and died due to sepsis and acute upper gastrointestinal bleeding one month after failed embolization. For patients with SAH, only one patient required ventriculoperitoneal shunt.

CONCLUSIONS

DAVFs of the CCJ along the first spinal nerve are rare and a unique subtype of DAVFs at the CCJ. These fistulas account for 1.74 % of all intracranial and spinal DAVFs in the present study. SAH is the major manifestation of DAVFs at C1 spinal nerve that may be overlooked on routine initial DSA. Rotational CT angiography is useful for clarification of the angioarchitecture of these fistulas, including small feeding artery and venous varix. Surgical treatment by interruption of the intradural draining vein should be the treatment of choice for C1 spinal nerve DAVF.

Subarachnoid hemorrhage due to a craniocervical junction arteriovenous fistula associated with thrombus formation in the internal jugular vein: illustrative case

BACKGROUND

A craniocervical junction arteriovenous fistula (CCJAVF) is a rare vascular malformation, and its etiology remains unclear. Here, to the best of the authors' knowledge, they present the first case of CCJAVF associated with thrombus formation in the ipsilateral internal jugular vein.

OBSERVATIONS

An 80-year-old man presented with a sudden occipital headache. Computed tomography revealed a subarachnoid hemorrhage surrounding the brainstem and upper cervical cord. Digital subtraction angiography showed a CCJAVF fed by the left C2 radiculomeningeal artery with ascending intracranial drainage and epidural plexus. After endovascular treatment, the authors retrospectively found that his ipsilateral internal jugular vein and innominate vein were occluded with a huge thrombus at admission.

LESSONS

This case suggested a restricted antegrade venous flow due to thrombus-induced progressive retrograde intracranial drainage causing hemorrhage. Venous hypertension should be considered one of the causes of hemorrhage due to CCJAVF as well as intracranial arteriovenous fistulas.

Neurosurgical versus endovascular treatment of craniocervical junction arteriovenous fistulas: a multicenter cohort study of 97 patients

OBJECTIVE

Craniocervical junction (CCJ) arteriovenous fistulas (AVFs) are treated using neurosurgical or endovascular options; however, there is still no consensus on the safest and most effective treatment. The present study compared the treatment results of neurosurgical and endovascular procedures for CCJ AVFs, specifically regarding retreatment, complications, and outcomes.

METHODS

This was a multicenter cohort study authorized by the Neurospinal Society of Japan. Data on consecutive patients with CCJ AVFs who underwent neurosurgical or endovascular treatment between 2009 and 2019 at 29 centers were analyzed. The primary endpoint was the retreatment rate by procedure. Secondary endpoints were the overall complication rate, the ischemic complication rate, the mortality rate, posttreatment changes in the neurological status, independent risk factors for retreatment, and poor outcomes.

RESULTS

Ninety-seven patients underwent neurosurgical (78 patients) or endovascular (19 patients) treatment. Retreatment rates were 2.6% (2/78 patients) in the neurosurgery group and 63% (12/19 patients) in the endovascular group (p < 0.001). Overall complication rates were 22% and 42% in the neurosurgery and endovascular groups, respectively (p = 0.084). Ischemic complication rates were 7.7% and 26% in the neurosurgery and endovascular groups, respectively (p = 0.037). Ischemic complications included 8 spinal infarctions, 2 brainstem infarctions, and 1 cerebellar infarction, which resulted in permanent neurological deficits. Mortality rates were 2.6% and 0% in the neurosurgery and endovascular groups, respectively (p > 0.99). Two patients died of systemic complications. The percentages of patients with improved modified Rankin Scale (mRS) scores were 60% and 37% in the neurosurgery and endovascular groups, respectively, with a median follow-up of 23 months (p = 0.043). Multivariate analysis identified endovascular treatment as an independent risk factor associated with retreatment (OR 54, 95% CI 9.9-300; p < 0.001). Independent risk factors associated with poor outcomes (a postoperative mRS score of 3 or greater) were a pretreatment mRS score of 3 or greater (OR 13, 95% CI 2.7-62; p = 0.001) and complications (OR 5.8; 95% CI 1.3-26; p = 0.020).

CONCLUSIONS

Neurosurgical treatment was more effective and safer than endovascular treatment for patients with CCJ AVFs because of lower retreatment and ischemic complication rates and better outcomes.

Ischemic complications in the neurosurgical and endovascular treatments of craniocervical junction arteriovenous fistulas: a multicenter study

OBJECTIVE

A recent comparative analysis between neurosurgical and endovascular treatments for craniocervical junction (CCJ) arteriovenous fistulas (AVFs) revealed better treatment outcomes in the neurosurgery group than in the endovascular group. This finding was attributed to the higher than expected rate of ischemic complications in the endovascular group than in the neurosurgery group (26% vs 7.7%, p = 0.037). The aim of the present study was to describe ischemic complications associated with treatments for CCJ AVFs.

METHODS

This descriptive study was authorized by the Neurospinal Society of Japan. Data from 97 consecutive patients with CCJ AVFs who underwent neurosurgical (n = 78) or endovascular (n = 19) treatment between 2009 and 2019 were collected from 29 centers. The primary endpoints were details on ischemic complications and their risk factors. Secondary endpoints were details on other complications.

RESULTS

Among all major complications, ischemic complications were the most common (11% of 97 patients), followed by hemorrhagic complications (7.2%), hydrocephalus (2.1%), and CSF leakage (2.1%). Ischemic complications included 8 spinal, 2 brainstem, and 1 cerebellar infarctions. Iatrogenic occlusion of the anterior or posterior spinal artery from the radiculomedullary or radiculopial arteries caused these complications. Ischemic complications resulted in neurological deficits, including motor paresis, sensory disturbances, and brainstem dysfunction. The modified Rankin Scale score was 3 or higher in 36% of patients with ischemic complications at the final follow-up of 23 months. Risk factors associated with ischemic complications were endovascular treatment (OR 4.3, 95% CI 1.1-16) and spinal feeding arteries (OR 3.8, 95% CI 1.03-14). Most of the other complications were addressed by additional treatment without permanent neurological deficits.

CONCLUSIONS

Among ischemic complications associated with treatments for CCJ AVFs, spinal infarctions were the most common and were mostly attributed to endovascular procedures for CCJ AVFs fed by spinal arteries. These results support the use of neurosurgery as the first-line treatment for CCJ AVFs.

Incidence and clinical characteristics of spinal arteriovenous shunts: hospital-based surveillance in Okayama, Japan

OBJECTIVE

There have been no accurate surveillance data regarding the incidence rate of spinal arteriovenous shunts (SAVSs). Here, the authors investigate the epidemiology and clinical characteristics of SAVSs.

METHODS

The authors conducted multicenter hospital-based surveillance as an inventory survey at 8 core hospitals in Okayama Prefecture between April 1, 2009, and March 31, 2019. Consecutive patients who lived in Okayama and were diagnosed with SAVSs on angiographic studies were enrolled. The clinical characteristics and the incidence rates of each form of SAVS and the differences between SAVSs at different spinal levels were analyzed.

RESULTS

The authors identified a total of 45 patients with SAVSs, including 2 cases of spinal arteriovenous malformation, 5 cases of perimedullary arteriovenous fistula (AVF), 31 cases of spinal dural AVF (SDAVF), and 7 cases of spinal epidural AVF (SEAVF). The crude incidence rate was 0.234 per 100,000 person-years for all SAVSs including those at the craniocervical junction (CCJ) level. The incidence rate of SDAVF and SEAVF combined increased with advancing age in men only. In a comparative analysis between upper and lower spinal SDAVF/SEAVF, hemorrhage occurred in 7/14 cases (50%) at the CCJ/cervical level and in 0/24 cases (0%) at the thoracolumbar level (p = 0.0003). Venous congestion appeared in 1/14 cases (7%) at the CCJ/cervical level and in 23/24 cases (96%) at the thoracolumbar level (p < 0.0001).

CONCLUSIONS

The authors reported detailed incidence rates of SAVSs in Japan. There were some differences in clinical characteristics of SAVSs in the upper spinal levels and those in the lower spinal levels.

Clinical heterogeneity of low flow spinal arteriovenous fistulas; a case series

Background

Spinal AVF (SAVF), a potentially treatable cause of myelopathy, remains a challenging diagnosis. Its rarity and non-specific imaging findings often result in misdiagnosis despite a high index of clinical suspicion. The classically described high T2 signal in the spinal cord or prominent vascular flow voids in the intradural space were not infrequently missed on initial imaging, only to be picked up at follow-up imaging after progression of symptoms. Additionally, small sized fistulas(< 1 mm) and SAVF involving less frequent locations like the craniocervical junction in a patient presenting with paraplegia further complicates the diagnosis. On rare occasions, acute atypical presentation following a surgery adds to the conundrum. Definite diagnosis with spinal angiography, the gold-standard modality requires the expertise of highly skilled interventionists which may otherwise lead to false negative findings. We describe four SAVF patients with unconventional presentations, highlighting less described clinical findings.

Case presentation

First was a 50-year-old man presented with spastic paraparesis and was found to have an AVF at the cervical region arising from the vertebral artery. Second, a 45-year-old man with acute paraplegia post-operatively, initially treated for a transverse myelitis before lumbar region AVF was detected. Thirdly, a 27-year-old man presented with subacute lower thoracic myelopathy and deteriorated after corticosteroid treatment. The last patient, who initially appeared to have conus medullaris/cauda equina syndrome had a SAVF at the mid thoracic level. Presentation varied with some exhibiting acute deterioration mimicking other spinal cord pathology such as inflammatory disorders. All patients eventually underwent endovascular treatment with successful embolization of SDAVF. None of them exhibited further neurological deterioration after embolization.

Conclusion

Successful treatment of SAVF is possible provided the diagnosis is made early, allowing timely intervention. Certain clues may aid the diagnosis. Firstly, arteriovenous fistula can be located distant to the clinical localization of myelopathy resulting in the unexpected longitudinally extensive spinal cord signal change. This clinical-radiological discrepancy can be a useful clue in diagnosing SAVF. Secondly, an acute myelopathic presentation immediately post-surgery may be related to SAVF. Other SAVF feature of note includes progressive myelopathy mimicking immune-mediated myelitis among young adults below 30 years of age refractory to immune therapy.

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.

Usefulness of arterial spin labeling in the evaluation for dural arteriovenous fistula of the craniocervical junction

In the diagnosis of an intracranial dural arteriovenous fistula (DAVF), arterial spin labeling (ASL), a sequence of magnetic resonance imaging (MRI) to depict high-blood-flow intracranial lesions, has been reported as a useful and noninvasive tool, not only to predict the presence of cortical venous drainage and draining veins, but also to confirm persistent obliteration after treatment. However, such utility of ASL has not been reported in DAVF of the craniocervical junction (CCJDAVF) because of the rarity of this disease and uncertainty in the acquisition of precise images.

We report a case of CCJDAVF presenting with myelopathy. Preoperative ASL images showed an abnormal high-intensity signal in the craniocervical junction, consistent with the anterior spinal vein and draining veins, which were also identified by digital subtraction angiography. After successful surgical treatment for the disease, MRI and 4-dimensional computed tomography angiography (4DCTA) confirmed complete disappearance of CCJDAVF. The ASL images also showed no abnormal intensity signal. The patient was followed-up using ASL, and no recurrence of high-intensity signal was observed.

As repetitive image examination is mandatory in the follow-up of a patient with DAVF to exclude recurrence, ASL is highly beneficial because of the unnecessity of an exogenous contrast medium and high credibility to depict the disease. The craniocervical junction may be out of the field of view in routine MRI. Special attention must be paid to setting the field of view and post labeling delay (PLD) to obtain precise images of ASL in CCJDAVF.

Arteriovenous Fistula at the Craniocervical Junction Found After Cervical Laminoplasty for Ossification of the Posterior Longitudinal Ligament

Ossification of the posterior longitudinal ligament (OPLL) is common in East Asia. Arteriovenous fistula at the craniocervical junction (CCJ-AVF), in contrast, is rare. As OPLL occurs most often in the cervical region, these 2 conditions can coexist in the cervical spinal canal of a single patient. We report a case of CCJ-AVF found after cervical laminoplasty (CLP) for OPLL. A 68-year-old man experienced progressive myelopathy due to cervical OPLL. Magnetic resonance imaging (MRI) revealed a high-intensity area inside the spinal cord. CLP was performed and his symptoms immediately improved. Three months after CLP, however, myelopathy recurred. MRI revealed an exacerbated and enlarged high-intensity area inside the cord from the medulla oblongata to the C4/5 level with a flow void around the cord. Left vertebral artery angiography revealed CCJ-AVF with ascending and descending draining veins. Direct surgery was performed to interrupt shunt flow into the draining veins. The patient’s symptoms improved to a limited degree. In this case, increased pressure inside the spinal canal due to OPLL might have decreased the shunt flow of the CCJ-AVF. Thus, the venous congestion induced by CCJ-AVF might have been exacerbated after the pressure was removed by CLP. Magnetic resonance angiography screening could help detect concurrent CCJ-AVF and OPLL.

Far Lateral Approach for Disconnection of Craniocervical Junction Dural Arteriovenous Fistula Presented with Myelopathy and Hydrocephalus

We report a case of craniocervical junction dural arteriovenous fistula (dAVF) presented with myelopathy and normal pressure hydrocephalus, and was treated with hybrid approach of embolization and surgical disconnection. A 68-year-old gentleman presented with 1 year history of unsteady gait and sphincter disturbance. Magnetic resonance imaging (MRI) showed abnormally enlarged and tortuous vessels over right cerebellomedullary cistern. Digital subtraction angiogram (DSA) showed Cognard's type-V dAVF at craniocervical junction. Catheter embolization was performed via external carotid artery and finally surgical disconnection was done with far lateral approach ( Fig. 1 ). Postoperative DSA showed no more arteriovenous shunting ( Fig. 2 ). Clinically the patient improved after a course of rehabilitation. Dural AVF at craniocervical junction is rare and its clinical presentation can be highly variable from subarachnoid hemorrhage to brainstem dysfunction. Identification of the exact fistula site is essential in surgical planning. Surgery is effective and safe to achieve complete obliteration and good clinical outcome. 123456

The link to the video can be found at: https://youtu.be/xI48stSlWpY .

Surgical Management for Craniocervical Junction Arteriovenous Fistula Targeting the Intradural Feeder

BACKGROUND

Craniocervical junction arteriovenous fistula (CCJAVF) has a variety of forms, including dural and perimedullary arteriovenous fistulas. Owing to this anatomic variety, the terminologies for classifying CCJAVF, most of which aim to describe angiographic structures, have yet to be firmly established, and the current taxonomic classifications do not facilitate surgical strategies. Herein we focused on the existence of intradural feeder vessels, allowing the identification of 2 types of CCJAVF. This retrospective study aimed to assess the usefulness of our diagnostic classification for CCJAVF surgery.

METHODS

We divided CCJAVF into 2 types: CCJAVF with an intradural feeder vessel and CCJAVF without an intradural feeder vessel. For the former type, we set the surgical goal of interrupting the intradural feeder and the draining veins behind the posterior spinal nerve. For the latter type, the surgical goal was to interrupt the draining veins behind the posterior spinal nerve. We retrospectively analyzed the outcomes of our surgical cases.

RESULTS

Of 12 patients with CCJAVF, 8 underwent direct surgery. No patients showed exacerbation of neurological symptoms after surgery. One patient needed a second operation for residual shunt, and another patient developed an asymptomatic angiographic recurrence in the epidural space detected on follow-up imaging. The overall outcomes of surgical cases were good with an average modified Rankin Scale score of 1.0.

CONCLUSIONS

Our results indicate that our diagnostic classification for CCJAVF has the potential to simplify CCJAVF treatment without compromising patient outcomes.

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.

Sphenoid dural arteriovenous fistulas

Sphenoid wing dural AVFs represent a rare clinical entity. These lesions may be asymptomatic or present with focal neurologic deficits, intracranial venous hypertension, or intracranial hemorrhage. Diagnosis is based on clinical findings and diagnostic imaging. They are alternatively classified as lesions of either the greater or lesser wings of the sphenoid bone. We performed a search of the PubMed database of studies evaluating the clinical behavior and surgical and endovascular therapies of these lesions. Dural AVFs draining into the superficial middle cerebral vein and/or laterocavernous sinus, or rather, lesions of the greater wing of the sphenoid, exhibit a greater likelihood of developing an aggressive clinical course, with higher probability of cortical venous reflux and consequent intracranial venous hypertension, intracranial hemorrhage, and symptomatic presentation. Dural AVFs of the sphenoparietal sinus, that is, lesions of the lesser wing of the sphenoid, typically exhibit a more benign clinical course, as there is a prominent epidural venous drainage into the cavernous sinus, reducing the risk of cortical venous reflux, and consequently, the probability of intracranial venous hypertension, hemorrhage, and floridly symptomatic presentation. These lesions may be treated via surgical clipping of the fistulous point, transarterial or transvenous embolization, and/or stereotactic radiosurgery. Though surgical intervention was the principal therapy due to facility of craniotomy access to the fistulous point, embolization has become standard of care permitted by innovation in endovascular technology. The natural history, clinical presentation, angioarchitecture, diagnosis, and management of these lesions are reviewed and discussed.

Transvenous embolization for craniocervical junction epidural arteriovenous fistula with a pial feeder aneurysm

Arteriovenous fistulas at the craniocervical junction are rare vascular malformations with frequent hemorrhagic presentations, which may have a concurrent pial feeder aneurysm. A 65-year-old man presented with subarachnoid hemorrhage and angiography showed an epidural arteriovenous fistula at the C-2 level with an anterior spinal feeder aneurysm without perimedullary venous drainage. Transarterial coil embolization of the ruptured aneurysm and partial Onyx embolization of the shunt led to thrombosis of the aneurysm. However, three years later angiography showed an increased shunt flow and recurrence of the aneurysm. Transvenous embolization of the shunt using coils and Onyx yielded complete obliteration of the shunt, thus leading to occlusion of the aneurysm. This case demonstrates that partial transarterial embolization of arteriovenous fistula leaves a risk of rebleeding, whereas complete obliteration of the shunt with a transvenous approach can lead to disappearance of the flow-related aneurysm without embolization of the aneurysm itself.

Results of 1940 embolizations for dural arteriovenous fistulas: Japanese Registry of Neuroendovascular Therapy (JR-NET3)

OBJECTIVE

Embolization is the most common treatment for dural arteriovenous fistulas (dAVFs). A retrospective, multicenter observational study was conducted in Japan to clarify the nature, frequency, and risk factors for complications of dAVF embolization.

METHODS

Patient data were derived from the Japanese Registry of Neuroendovascular Therapy 3 (JR-NET3). A total of 40,169 procedures were registered in JR-NET3, including 2121 procedures (5.28%) in which dAVFs were treated with embolization. After data extraction, the authors analyzed complication details and risk factors in 1940 procedures performed in 1458 patients with cranial dAVFs treated with successful or attempted embolization.

RESULTS

Transarterial embolization (TAE) alone was performed in 858 cases (44%), and transvenous embolization (TVE) alone was performed in 910 cases (47%). Both TAE and TVE were performed in one session in 172 cases (9%). Complications occurred in 149 cases (7.7%). Thirty-day morbidity and mortality occurred in 55 cases (2.8%) and 16 cases (0.8%), respectively. Non-sinus-type locations, radical embolization as the strategy, procedure done at a hospital that performed dAVF embolization in fewer than 10 cases during the study period, and emergency procedures were independent risk factors for overall complications.

CONCLUSIONS

Complication rates of dAVF embolization in Japan were acceptable. For better results, the risk factors identified in this study should be considered in treatment decisions.

Efficacy of Intraarterial Fluorescence Video Angiography in Surgery for Dural and Perimedullary Arteriovenous Fistula at Craniocervical Junction

OBJECTIVE

Confirming the exact location of a fistula and the origins of draining veins during surgery for dural and perimedullary arteriovenous fistulas (AVFs) is crucial but sometimes inadequately performed, which can result in incomplete elimination of the lesion. Intraoperative digital subtraction angiography (DSA) is the gold standard for confirming the hemodynamics of an AVF; however, it cannot reveal the location of an AVF in the operative field. In this study, the efficacy of intraoperative intraarterial fluorescence video angiography during surgery for craniocervical junction dural and perimedullary AVFs was investigated.

METHODS

We repeatedly employed this technology to evaluate its usefulness in revealing the flow dynamics and anatomy of AVFs and to confirm complete elimination of the fistula.

RESULTS

Seven AVFs were included in this study. Their locations were C1 in 5 cases and C2 in 2 cases. Intraarterial fluorescence video angiography precisely revealed the locations of 3 dural AVFs, 1 perimedullary AVF, and 3 co-occurring dural and perimedullary AVFs. Frame-by-frame review of the fluorescence video angiography clearly demonstrated that fluorescence appeared earlier in the perimedullary AVF than in the draining vein through the dural AVF after intraarterial injection in all 3 co-occurring cases. Complete elimination of the AVF was also confirmed in all cases by fluorescence video angiography, as well as intraoperative and follow-up DSA.

CONCLUSIONS

Intraarterial fluorescence video angiography, particularly frame-by-frame review, enables surgeons to distinguish the flow dynamics of AVFs and contributes to the planning of effective surgical strategies for optimal results.

Usefulness of preoperative cone beam computed tomography and intraoperative digital subtraction angiography for dural arteriovenous fistula at craniocervical junction: Technical case report

Background:

Direct surgery is commonly selected for the treatment of cranio-cervical junction dural arteriovenous fistula and its outcome is more satisfactory than that of embolization. Intraoperative treatment evaluation is relatively easy in embolization, whereas in direct surgery it can be difficult.

Case Description:

A 67-year-old male suffered a subarachnoid hemorrhage. On three-dimensional (3D) images of preoperational cone-beam computed tomography (CBCT), the structure of the draining vein was depicted in detail along with the surrounding bone structures. The radial artery penetrated the dura mater, and it was found that there were two veins derived from the radiculospinal vein; one was the anterior radicular vein descending toward the dorsal side (the shallow layer of the surgical field) and the other was the anterior spinal medullary vein ascending toward the ventral side (the deep layer of the surgical field) and flowing out to the anterior spinal vein.

Conclusion:

Without detailed assessments with preoperative CBCT, the surgery might have been done with dissection of only the anterior radicular vein in the shallow layers. For identification of the draining vein located deep in the surgical field, such as the cranio-cervical junction, careful assessments using 3D CBCT images are important.

Dural Arteriovenous Fistulas at the Craniocervical Junction: A Series Case Report

BACKGROUND

Craniocervical junction dural arteriovenous fistulas (CJDAVFs) are rare vascular malformations with unclear clinical characteristics. This study investigated the clinical characteristics and outcomes of patients with CJDAVFs.

METHODS

Thirty-eight patients with CJDAVFs who had undergone either conservative or surgical treatment were retrospectively analyzed.

RESULTS

Eleven (28.9%) patients were women and 27 (71.1%) were men (median age, 52.5 years). Two (5.3%) had myelopathy, and 36 (94.7%) had subarachnoid hemorrhage (SAH). Three patients had SAH recurrence before treatment. Five patients (13.9%) with SAH initially had negative results on angiography, which may have been due to a low-flow fistula without varicose veins (P = 0.034) and acute hydrocephalus (P = 0.084). Coincidental vascular lesions were noted in 5 patients (13.2%). Caudal drainage was mainly found in patients with myelopathy, whereas superolateral drainage was frequently observed in patients with SAH (P = 0.021). Thirty-six (94.7%) patients underwent microsurgery; of these, 33 (91.7%) had favorable outcomes and 3 (8.3%) had unfavorable outcomes. The main neurosurgical complications included acute hydrocephalus in 4 (10.5%) and new-onset mild persistent myelopathy in 6 (15.7%). According to the univariate analysis, the presence of myelopathy predicted poor outcomes, whereas SAH predicted favorable outcomes (P = 0.004). However, the multivariate analysis did not show statistical significance.

CONCLUSIONS

SAH is a common presenting sign of CJDAVF that may be overlooked on initial cerebral angiography, especially in patients with acute hydrocephalus and a low-flow fistula without varicose veins. Microsurgery involving disconnecting the draining vein is effective and beneficial. Further studies should be performed to investigate predictive factors influencing the prognosis.