Transcondylar approach for dural arteriovenous fistulas of the cervicomedullary junction

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.

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.

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.

Clinical importance of the posterior meningeal artery: a review of the literature

The posterior meningeal artery, which arises from the vertebral artery, is a critical artery in neurological lesions. However, a comprehensive review of the importance of the posterior meningeal artery is currently lacking. In this study, we used the PubMed database to perform a review of the literature on the posterior meningeal artery to increase our understanding of its role in vascular lesions. The posterior meningeal artery provides the main blood supply to the paramedial and medial portions of the dura covering the cerebellar convexity. The posterior meningeal artery is often involved in dural arteriovenous fistulas occurring near the posterior fossa, and the posterior meningeal artery can be the path for transarterial embolisation or a path through which to monitor the degree of dural arteriovenous fistula embolisation. In posterior circulation ischaemia and moyamoya disease, the posterior meningeal artery can form transdural anastomoses with pial arteries at the surface of the brain, and these can help prevent ischemia. The posterior meningeal artery can also develop aneurysms, most of which are traumatic pseudoaneurysms; patients should therefore be treated in a timely manner or followed up carefully in cases of rebleeding. In addition, during a craniotomy, the posterior meningeal artery should be protected intraoperatively to avoid damaging any transdural anastomosis that may be present. In addition, when the posterior meningeal artery is the main feeding artery of an intracranial tumour, that artery is a satisfactory path for preoperative embolisation. Briefly, the posterior meningeal artery is a very important artery in neurosurgery.

Angioarchitecture of arteriovenous fistulas at the craniocervical junction: a multicenter cohort study of 54 patients

OBJECTIVE The aim of this retrospective multicenter cohort study was to assess the details of the angioarchitecture of arteriovenous fistulas (AVFs) at the craniocervical junction (CCJ) and to determine the associations between the angiographic characteristics and the clinical presentations and outcomes. METHODS The authors analyzed angiographic and clinical data for patients with CCJ AVFs from 20 participating centers that are members of the Japanese Society for Neuroendovascular Therapy (JSNET). Angiographic findings (feeding artery, location of AV shunt, draining vein) and patient data (age, sex, presentation, treatment modality, outcome) were tabulated and stratified based on the angiographic types of the lesions, as diagnosed by a member of the CCJ AVF study group, which consisted of a panel of 6 neurointerventionalists and 1 spine neurosurgeon. RESULTS The study included 54 patients (median age 65 years, interquartile range 61-75 years) with a total of 59 lesions. Five angiographic types were found among the 59 lesions: Type 1, dural AVF (22 [37%] of 59); Type 2, radicular AVF (17 [29%] of 59); Type 3, epidural AVF (EDAVF) with pial feeders (8 [14%] of 59); Type 4, EDAVF (6 [10%] of 59); and Type 5, perimedullary AVF (6 [10%] of 59). In almost all lesions (98%), AV shunts were fed by radiculomeningeal arteries from the vertebral artery that drained into intradural or epidural veins through AV shunts on the dura mater, on the spinal nerves, in the epidural space, or on the spinal cord. In more than half of the lesions (63%), the AV shunts were also fed by a spinal pial artery from the anterior spinal artery (ASA) and/or the lateral spinal artery. The data also showed that the angiographic characteristics associated with hemorrhagic presentations-the most common presentation of the lesions (73%)-were the inclusion of the ASA as a feeder, the presence of aneurysmal dilatation on the feeder, and CCJ AVF Type 2 (radicular AVF). Treatment outcomes differed among the angiographic types of the lesions. CONCLUSIONS Craniocervical junction AVFs commonly present with hemorrhage and are frequently fed by both radiculomeningeal and spinal pial arteries. The AV shunt develops along the C-1 or C-2 nerve roots and can be located on the spinal cord, on the spinal nerves, and/or on the inner or outer surface of the dura mater.

Natural history and treatment of craniocervical junction dural arteriovenous fistulas

Dural arteriovenous fistulas (DAVFs) located at the craniocervical junction are rare vascular malformations with distinctive features, and their natural history and the optimal treatment strategy remains unclear. We retrospectively reviewed eight patients with craniocervical junction DAVF who were evaluated at our institution between 2009 and 2012. We also conducted a MEDLINE search for all reports of craniocervical junction DAVF between 1970 and 2013, and reviewed 119 patients from 56 studies. From a total of 127 patients, 46 (37.1%) presented with myelopathy, 53 (43.1%) with subarachnoid hemorrhage (SAH), and four (3.3%) with brainstem dysfunction. SAH was typically mild, most often Hunt and Hess Grade I or II (83.3%), and associated with ascending venous drainage via the intracranial veins (p<0.001). Higher rates of obliteration were observed after microsurgery compared to embolization. Overall, younger age (odds ratio [OR] 1.07; 95% confidence interval [CI] 1.01-1.12; p=0.011), hemorrhagic presentation (OR 0.17; 95% CI 0.06-0.50; p=0.001), and microsurgery (OR 0.23; 95% CI 0.08-0.6; p=0.004) were independently predictive of good outcome at the last follow-up. Microsurgery was the only independent predictor of overall improvement at the last follow-up (OR 4.35; 95% CI 1.44-13.2; p=0.009). Prompt diagnosis and microsurgical management, offering a greater chance of immediate obliteration, may optimize the outcomes for patients with craniocervical junction DAVF. Endovascular treatment is often not feasible due to lesion angioarchitecture, and is associated with a higher risk of lesion recanalization or recurrence. However, long term studies with newer embolic agents such as Onyx (ev3 Endovascular, Plymouth, MN, USA) are yet to be performed.

Dural arteriovenous fistulas at the craniocervical junction: a systematic review

Background

Dural arteriovenous fistulas (DAVFs) at the craniocervical junction are uncommon but clinically important abnormalities.

Objective

To investigate the clinical characteristics of patients with DAVFs at the craniocervical junction and assess angiographic features associated with bleeding at presentation.

Methods

We systematically reviewed the literature and searched PubMed and EMBASE for all relevant English language articles published between 1980 and 2014. The clinical presentation, angiographic characteristics, and treatment were assessed. The clinical differences between a subarachnoid hemorrhage (SAH) group and a non-SAH group were statistically examined.

Results

Fifty-six patients were identified after a review of the literature (mean age 55.6 years; male to female ratio=3:1). Twenty-one patients (37.5%) presented with hemorrhage including SAH and posterior fossa hemorrhage. There was no significant difference in patient age, sex, or location of the DAVF between the SAH group and the non-SAH group. Intracranial venous drainage was significantly associated with SAH (p<0.001). The presence of a varix was significantly associated with SAH (p=0.001). Open surgery had a significantly higher efficacy of initial complete obliteration than embolization (100% vs 71.4%, p<0.01).

Conclusions

DAVFs at the craniocervical junction are rare lesions, which often present with hemorrhage. Intracranial venous drainage and a venous varix are associated with increased risk of SAH. Surgical interruption of the feeding arteries or draining veins is an effective and reliable method for treating DAVFs at the craniocervical junction. Embolization is a feasible alternative to surgery in the treatment of selective DAVFs.

Analysis of venous drainage in three patients with extradural spinal arteriovenous fistulae at the craniovertebral junction with potentially benign implication

BACKGROUND

Extradural arteriovenous fistulae (AVFs) are vascular malformations that result from a direct connection between an extradural artery and vein, resulting in a high flow fistula that drains into the epidural venous system. Extradural AVFs may cause myelopathy when distended epidural veins compress the cord or when venous hypertension causes venous stasis within the spinal cord, and are uncommon causes of subarachnoid hemorrhage (SAH), although the presence of intracranial drainage is a risk factor for SAH. There are numerous reports of SAH and AVF with rostral intracranial venous drainage, implying an intradural drainage pathway. To our knowledge, a cervical spinal AVF at the craniovertebral junction (occurring between the occiput and C2) with exclusively extradural drainage and without a significant epidural component has not been described previously.

METHODS

A retrospective review was performed identifying three patients treated at our hospital with cervical spinal AVF and extradural venous drainage.

RESULTS

We present three cases of cervical spinal AVF with exclusive extradural venous drainage without accompanying intradural drainage--cranial or spinal. All three patients with exclusively extradural drainage have done well after 24 months of follow-up. The anatomical, clinical, and radiologic features are presented.

CONCLUSIONS

Patients with cervical AVF and exclusively extradural drainage pathways form a separate entity, representing a subset with a less ominous natural history.

Factors influencing the prognosis in intracranial dural arteriovenous fistulas with perimedullary drainage

OBJECTIVE

Intracranial dural arteriovenous fistulas with perimedullary venous drainage (IDAVFPD) are classified as type V dural arteriovenous fistulas. Publications are limited to single case reports and small case series. We conducted a systematic review of the literature for patients with IDAVFPD. The aim of this study is to identify the predictive factors of poor prognosis in patients with IDAVFPD.

METHODS

We present the case of a 48-year-old man who underwent surgical interruption of IDAVFPD. A complete MEDLINE search was then undertaken for all articles reporting outcomes data for IDAVFPD. According to the results we have divided the patient population into two groups: I, those patients who showed improvement after treatment, and II: those patients who did not show improvement. We conducted a comparative statistical analysis of the epidemiologic, clinical, radiologic, and therapeutic parameters between the two groups.

RESULTS

A total of 37 articles comprising with 58 cases were included for analysis with an average follow-up of 12 months. There were 36 patients in group I and 22 in group II. The average age was 57.8 years in group I and 54.3 years in group II (P=0.32). Onset of symptoms was acute or subacute in 57% of patients in group I, and in 50% of patients in group II (P=0.62). Bulbar signs were present in 28% of cases in group I and in 36% of cases in group II (P=0.49). Hyperintensity of the brainstem on T2-weighted sequence magnetic resonance imaging was more common in patients in group II (78%) compared with patients in group I (45%) (P=0.012). Patients who underwent surgical procedure have shown good outcomes compared to patients treated with endovascular approach (P=0.039).

CONCLUSIONS

The poor outcomes were correlated to the presence of brainstem signal abnormalities on magnetic resonance imaging, whereas the prognosis does not depend on age, sex, clinical presentation, or anatomic characteristics of the fistula.

Posterolateral Approaches to the Craniovertebral Junction

OBJECTIVE

The indications and operative technique for a number of posterolateral approaches to the craniovertebral junction (CVJ) are reviewed.

METHODS

The literature addressing posterolateral approaches to the CVJ is reviewed, and illustrative cases are presented.

RESULTS

The far lateral approach and its variants, including the transcondylar, supracondylar, and paracondylar approaches, are an effective means of addressing intradural anterior and anterolateral CVJ lesions. These approaches provide exposure of the lower third of the clivus, the foramen magnum, and the upper cervical spine; do not cross contaminated regions; and enable a watertight dural closure to be performed. They are associated with minimal morbidity and usually do not significantly decrease the stability of the CVJ.

CONCLUSION

All surgeons treating lesions of the CVJ should be familiar with the posterolateral approach and its modifications.

Intracranial subarachnoid hemorrhage resulting from cervical spine dural arteriovenous fistulas: literature review and case presentation

Cervical dural arteriovenous fistulas (dAVFs) are a rare cause of intracranial subarachnoid hemorrhage (SAH) but should be considered when other sources are not found. Subarachnoid hemorrhage caused by dAVF is thought to occur as a result of venous hypertension in most cases. The clinical presentation, acute onset of severe headache, is similar to that in patients with other causes of SAH; however, severe neurological deficits (Hunt and Hess Grade IV and V SAH) have not been reported in SAH caused by cervical dAVFs. Patients with this type of SAH commonly report suboccipital headache, neck pain, and nausea, and thus these hemorrhages can be easily dismissed as perimesencephalic SAH. Vigilant evaluation with 4-vessel cerebral angiography, including selective catherization of both proximal vertebral arteries, should be performed. The practice of unilateral vertebral artery injection with reflux into the contralateral vertebral and posterior inferior cerebellar arteries has the potential to overlook cervical dAVF. Magnetic resonance imaging may be useful to evaluate for other causes of SAH but is probably not sensitive for the identification of a cervical dAVF. Surgical treatment of this lesion has an excellent outcome.

Dural arteriovenous fistula of the lumbar spine presenting with subarachnoid hemorrhage. Case report and review of the literature

The authors report on a patient presenting with subarachnoid hemorrhage (SAH) that was initially attributed to an aneurysm of the right internal carotid artery. During surgical exploration and placement of a clip, however, it was observed that the aneurysm had not ruptured. Diagnostic workup including spinal magnetic resonance imaging revealed a vascular malformation of the lumbar spinal canal within a subarachnoid hematoma. Spinal angiography demonstrated a spinal dural arteriovenous fistula (DAVF) (Type I spinal arteriovenous malformation) with a feeding vessel arising from the L-4 radicular artery. In the literature, SAH due to spinal DAVFs is rare; only cases of dural fistulas of the craniocervical junction and the cervical spine have been reported. This is the first case of SAH that can be attributed to a lumbar DAVF. Although unusual even in cases of cervical DAVF, SAH as a presenting symptom may occur in spinal DAVF of any location. Nontraumatic SAH should not be prematurely attributed to the rupture of an intracranial aneurysm if the clinical findings and imaging results are inconclusive.