Surgical treatment of cranial arteriovenous malformations and dural arteriovenous fistulas

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.

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.

Treatment of Ethmoidal Dural Arteriovenous Fistulas: A Meta-analysis Comparing Endovascular versus Surgical Treatment

BACKGROUND

Dural arteriovenous fistulas (DAVFs) in the anterior cranial fossa constitute approximately 1%-1.5% of intracranial vascular malformations. Depending on the drainage patterns, the diagnosis of ethmoidal DAVFs should prompt treatment because of the high risk of bleeding. Available treatments strategies are surgical treatment and the endovascular approach.

OBJECTIVE

To compare the surgical treatment with the endovascular therapy in terms of complete obliteration and perioperative adverse events.

METHODS

This study was performed according to the PRISMA guidelines. Eligible studies were identified through a search of PubMed and Cochrane until February 2019. A random effects model meta-analysis of odds ratios (OR) was conducted and the I-square was used to assess heterogeneity. Good outcome was defined as no neurologic deterioration within 30 days after the procedure.

RESULTS

Five studies comprising 81 patients were included in the meta-analysis. Surgical disconnection was superior to endovascular therapy in terms of postprocedural complete obliteration rate (surgery group, 100% [n = 65/65]; endovascular therapy, 47% [n = 15/32]; OR, 32.19; 95% confidence interval, 5.46-189.72; I² = 9.9%) and 30-day good outcome (surgery group, 98% [n = 63/64]; endovascular therapy, 47% [n = 15/32]; OR, 21.90; 95% confidence interval, 1.94-247.27; I² = 53.6%). No significant differences in terms of 30-day stroke, transient ischemic attack; visual deficit, new-onset seizure, and intracranial hemorrhage were identified.

CONCLUSIONS

Surgical treatment was superior to endovascular therapy in terms of complete obliteration and overall good outcome. Adverse event rates were similar between the 2 groups. Future studies should be conducted to validate our results.

Interhemispheric Paracallosal Approach for an Arteriovenous Malformation of the Atrium: A Novel Technique

Background: Intraventricular lesions present a surgical challenge because of the complexity of the ventricular anatomy, various perforating arteries, and eloquent brain areas surrounding the system. The ventricular atrium is particularly challenging because of the cingulate gyrus, corpus callosum, optic pathways, and significant vascular structures. We present the case of a patient for whom we used a new surgical approach to reach a lesion in the ventricular atrium. Case Report: A 26-year-old male presented with an intraventricular hemorrhage, acute hydrocephalus, and a grade III arteriovenous malformation (AVM) in the atrium of the left lateral ventricle. We approached the AVM through a posterior parietooccipital paracallosal interhemispheric approach. Instead of transecting the cingulate cortex as is traditionally done, we gently retracted the cingulate gyrus and made a small paracallosal incision to reach the atrium of the left lateral ventricle. The surgery was uneventful. The patient recovered well and was discharged home on postoperative day 3 without any deficits. Conclusion: This case illustrates a novel variation to an established approach to the ventricular atrium. With this technique, the surgeon minimizes disruption of brain tissue and thereby avoids the associated postoperative deficits associated with traditional approaches (transcortical, transcingulate, and conventional transcallosal). Tractography studies and a large cohort of patients are necessary to ensure the reproduction of good outcomes.

Embolization of cranial dural arteriovenous fistulas in the liquid embolic era: A Sydney experience

Endovascular management of dural arteriovenous fistulas has become a mainstay of treatment. In particular, modern techniques have allowed greater fistula penetration and likelihood of complete obliteration. However, the efficacy of newer agents has not been quantified outside of predominantly small case reports and case series. Furthermore, the Australian experience with fistula embolization has yet to be reported in the literature. To this aim, we performed a retrospective review of our endovascular management of a large cohort of cranial dural arteriovenous fistulas in the liquid embolic era. This retrospective case series included ninety-six consecutive patients of any Cognard grade, treated between 2005 and 2016. Liquid embolic agents were used exclusively in eighty-three cases. The overall complete obliteration rate was 89.6% with a residual fistula rate of 2%, and complication rate of 8.3%. This Sydney, Australia cohort demonstrates excellent treatment effect and safety outcomes and thus supports the primary treatment of this condition by endovascular means.

Dural arteriovenous fistula masquerading as pulsatile tinnitus: radiologic assessment and clinical implications

Pulsatile tinnitus (PT) is often an initial presenting symptom of dural arteriovenous fistula (dAVF), but it may be overlooked or diagnosed late if not suspected on initial diagnostic work-up. Here, we assess anatomical features, treatment outcomes, and clinical implications of patients with PT due to dAVF. Of 220 patients who were diagnosed with dAVF between 2003 and 2014, 30 (13.6%) presented with only PT as their initial symptom. The transverse-sigmoid sinus (70.0%) was the most common site, followed by the hypoglossal canal (10.0%) and the middle cranial fossa (6.7%) on radiologic evaluation. Regarding venous drainage patterns, sinus or meningeal venous drainage pattern was the most common type (73.3%), followed by sinus drainage with a cortical venous reflux (26.7%). PT disappeared completely in 21 (80.8%) of 26 patients who underwent therapeutic intervention with transarterial embolization of the fistula, improved markedly in 3 (11.5%), and remained the same in 2 (7.7%). In conclusion, considering that PT may be the only initial symptom in more than 10% of dAVF, not only otolaryngologists but also neurologists and neurosurgeons should meticulously evaluate patients with PT. In most cases, PT originating from dAVF can be cured with transarterial embolization regardless of location and venous drainage pattern.

Diagnosis and management of intracranial dural arteriovenous fistulas

Dural arteriovenous fistula (DAVF) is a rare type of acquired intracranial vascular malformation. Recent progress in neuroimaging technology, such as advanced MRI and CT, provides non-invasive methods to accurately diagnose DAVF, including evaluation of the hemodynamics of the drainage veins. The clinical manifestations of DAVFs vary widely and depend on the location and venous drainage pattern of arteriovenous shunting. Patients with high grade DAVFs having cortical venous reflux should receive aggressive treatment to prevent the occurrence of intracranial hemorrhage and other neurological deficits related to venous congestion. Intra-arterial or intravenous endovascular embolization remains the primary therapy for high grade DAVF, while open surgery and stereotactic radiosurgery can serve as alternative treatment options. Early and accurate diagnosis with appropriate treatment is the goal for clinical management of DAVFs to reduce symptoms and prevent the development of venous congestion and stroke.

Four-dimensional computed tomography angiography is valuable in intracranial dural arteriovenous fistula diagnosis and fistula evaluation

This study was to evaluate the value of four-dimensional computed tomography angiography (4D-CTA) in the diagnosis of intracranial dural arteriovenous fistula (DAVF). This study included 16 patients who were diagnosed to have intracranial DAVF by digital subtraction angiography (DSA). The 4D-CTA was performed by Aquilion ONE multi-detector CT scanner (Toshiba Medical Systems, Japan) equipped with 320 × 0.5 mm detector rows. Standard biplane fluoroscopy equipments (Infinix, Toshiba Medical Systems, Japan and ADVANTX LC/LP, GE Medical Systems, Milwaukee, WI, USA) were applied in the diagnosis of intra-arterial DSA. Examinations were performed to evaluate the findings of DSA and 4D-CTA in each patient. The examination results were read by two independent readers in a blind manner. All results were documented on standardized scoring sheets. In all 16 cases, the same diagnosis results of intracranial DAVF were obtained from DSA and 4D-CTA. The results of subtype (Borden and Cognard classification), venous reflux and fistula sites were also accurately exhibited in 4D-CTA. In addition, there was a little discrepancy in identifying smaller and specific arterial branches and in distinguishing fistula type (focal or diffuse) using 4D-CTA. Good-to-excellent agreements were made between 4D-CTA and DSA. Therefore, 4D-CTA could be a feasible tool for the characterization of intracranial DAVF, with respect to determining fistula site and venous drainage.

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.

Endovascular and microsurgical treatment of cerebral arteriovenous malformations: Current recommendations

Background:

Cerebral arteriovenous malformations (AVMs) can be a heterogeneous pathological entity whose management requires a complex decision-making process due to the risks associated with their treatment and natural history. Despite the recently published conclusions of the aborted Randomized Trial of Brain Unruptured AVMs (ARUBA) trial, the authors of this article believe multimodality intervention in general and microsurgical resection in particular continue to play a major role in the management of carefully selected ruptured or unruptured AVMs.

Methods:

The authors provide an overview of their methodology for endovascular intervention and microsurgical resection and share their technical nuances for successful embolization and microsurgical resection of AVMs with special emphasis on complication avoidance.

Results:

The authors have achieved successful outcomes in embolization and resection of cerebral AVMs when using their methodology.

Conclusions:

These lesions are among the most technically difficult pathological entities handled by the cerebrovascular specialist, and an overview of technical concepts to help systematize this challenging and variable endeavor can improve the safety of their treatment.

The minipterional craniotomy for anterior circulation aneurysms: initial experience with 72 patients

BACKGROUND

The pterional craniotomy is well established for microsurgical clipping of most anterior circulation aneurysms. The incision and temporalis muscle dissection impacts postoperative recovery and cosmetic outcomes. The minipterional (MPT) craniotomy offers similar microsurgical corridors, with a substantially shorter incision, less muscle dissection, and a smaller craniotomy flap.

OBJECTIVE

To report our experience with the MPT craniotomy in select unruptured anterior circulation aneurysms.

METHODS

From January 2009 to July 2013, 82 unruptured aneurysms were treated in 72 patients, with 74 MPT craniotomies. Seven patients had multiple aneurysms treated with a single MPT craniotomy. The average patient age was 56 years (range: 24-87). Aneurysms were located along the middle cerebral artery (n = 36), posterior communicating (n = 22), paraophthalmic (n = 22), choroidal (n = 1), and dorsal ICA segments (n = 1). The MPT craniotomy utilized an incision just posterior to the hairline and a single myocutaneous flap.

RESULTS

The average aneurysm size was 5.45 mm (range: 1-14). There were no instances of compromised operative corridors requiring craniotomy extension. Three significant early postoperative complications included epidural and subdural hematomas requiring evacuation, and a middle cerebral artery infarction. Average length of hospitalization was 3.96 days (range: 2-20). Two patients required reoperation for wound infections. Average follow-up was 421 days (range: 5-1618). Minimal to no temporalis muscle wasting was noted in 96% of patients.

CONCLUSION

The MPT craniotomy is a worthwhile alternative to the standard pterional craniotomy. There were no instances of suboptimal operative corridors and clip applications when the MPT craniotomy was utilized in the treatment of unruptured middle cerebral artery and supraclinoid internal carotid artery aneurysms proximal to the terminal internal carotid artery bifurcation.

Advances in Surgical Approaches to Dural Fistulas

Dural arteriovenous fistulas are abnormal connections of dural arteries to dural veins or venous sinuses originating from within the dural leaflets. They are usually located near or within the wall of a dural venous sinus that is frequently obstructed or stenosed. The dural fistula sac is contained within the dural leaflets, and drainage can be via a dural sinus or retrograde through cortical veins (leptomeningeal drainage). Dural arteriovenous fistulas can occur at any dural sinus but are found most frequently at the cavernous or transverse sinus. Leptomeningeal venous drainage can lead to venous hypertension and intracranial hemorrhage. The various treatment options include transarterial and transvenous embolization, stereotactic radiosurgery, and open surgery. Although many of the advances in dural arteriovenous fistula treatment have occurred in the endovascular arena, open microsurgical advances in the past decade have primarily been in the tools available to the surgeon. Improvements in microsurgical and skull base approaches have allowed surgeons to approach and obliterate fistulas with little or no retraction of the brain. Image-guided systems have also allowed better localization and more efficient approaches. A better understanding of the need to simply obliterate the venous drainage at the site of the fistula has eliminated the riskier resections of the past. Finally, the use of intraoperative angiography or indocyanine green videoangiography confirms the complete disconnection of fistula while the patient is still on the operating room table, preventing reoperation for residual fistulas.

Hybrid surgery for dural arteriovenous fistula in the neurosurgical hybrid operating suite

Treatment of a dural arteriovenous fistula (AVF), which is difficult to access by either the surgical or endovascular approach, is challenging. A hybrid technique, combining a microsurgical approach and endovascular embolization, can provide less invasive management of dural AVFs in a modern neurosurgical hybrid operating suite. We present a case of intracerebral hemorrhage in the left cerebellum secondary to dural AVF, Cognard type IV with numerous tiny feeders from the ascending pharyngeal artery branches. No adequate arterial or venous route for endovascular embolization was found by neuroangiography. The hybrid technique, combining keyhole pterional craniotomy and embolization with n-butyl cyanoacrylate glue injection via direct cannulation of the periclival venous plexus, succeeded in obliterating the dural AVF. Intraoperative angiography showed successful embolization of the dural AVF without any complication. This report illustrates the usefulness of the neurosurgical hybrid operating suite for the treatment of difficult dural AVFs.

Hybrid surgery for dural arteriovenous fistula in the neurosurgical hybrid operating suite

Treatment of a dural arteriovenous fistula (AVF), which is difficult to access by either the surgical or endovascular approach, is challenging. A hybrid technique, combining a microsurgical approach and endovascular embolization, can provide less invasive management of dural AVFs in a modern neurosurgical hybrid operating suite. We present a case of intracerebral hemorrhage in the left cerebellum secondary to dural AVF, Cognard type IV with numerous tiny feeders from the ascending pharyngeal artery branches. No adequate arterial or venous route for endovascular embolization was found by neuroangiography. The hybrid technique, combining keyhole pterional craniotomy and embolization with n-butyl cyanoacrylate glue injection via direct cannulation of the periclival venous plexus, succeeded in obliterating the dural AVF. Intraoperative angiography showed successful embolization of the dural AVF without any complication. This report illustrates the usefulness of the neurosurgical hybrid operating suite for the treatment of difficult dural AVFs.

Temporary clamping of bilateral external carotid arteries for surgical excision of a complex dural arteriovenous fistula

Background:

Some complex dural arteriovenous fistulas (DAVFs) are lesions that typically have numerous arterial feeders. Surgery, including resection of fistulas or skeletonization of the diseased sinus, is still one of the important treatments for these lesions. However, major blood loss is usually encountered during craniotomy because of abundant arterial feeders from the scalp and transosseous vessels. We present a novel approach for obliteration of the fistulas with less blood loss.

Methods:

Our first case was a 52-year-old male who suffered from syncope and seizure. Cerebral digital subtraction angiography (DSA) revealed complex DAVFs with numerous arterial feeders from bilateral external carotid arteries (ECAs) and drainage into the superior sagittal sinus with cerebral venous reflux. The second case was a 48-year-old male presenting with chronic headache. His DSA also showed complex DAVFs along the superior sagittal sinus with cerebral venous reflux. In both cases, we performed the surgical procedure to obliterate the pathological fistulas after temporary clamping of bilateral ECAs and noted less blood loss than in the conventional surgery.

Results:

The follow-up DSA showed successful obliteration of the complex DAVFs on the first case and partial improvement on the second case followed by transarterial embolization (TAE). The symptoms of the both patients were relieved after surgery with good recovery.

Conclusion:

Temporary clamping of bilateral ECAs can improve the safety and ease the surgical excision for complex DAVFs. By using this technique, neurosurgeons can deal with aggressive DAVFs more confidently and calmly.

Impact on Seizure Control of Surgical Resection or Radiosurgery for Cerebral Arteriovenous Malformations

BACKGROUND:

Seizures are a common presenting symptom of arteriovenous malformations (AVMs). However, the impact of treatment modality on seizure control remains unclear.

OBJECTIVE:

To compare seizure control after surgical resection or radiosurgery for AVMs.

METHODS:

We analyzed retrospectively collected information for 378 patients with cerebral AVMs treated at our institution from 1990 to 2010. The application of strict inclusion criteria resulted in a study population of 164 patients.

RESULTS:

In our cohort, 31 patients (20.7%) had Spetzler-Martin grade I AVMs, 51 (34.0%) grade II, 47 (31.3%) grade III, 20 (13.3%) grade IV, and 1 (0.7%) grade V. Of the 49 patients (30%) presenting with seizures, 60.4% experienced seizure persistence after treatment. For these patients, radiosurgery was associated with seizure recurrence (odds ratio: 4.32, 95% confidence interval: 1.24-15.02, P = .021). AVM obliteration was predictive of seizure freedom at last follow-up (P = .002). In contrast, for patients presenting without seizures, 18.4% experienced de novo seizures after treatment, for which surgical resection was identified as an independent risk factor (hazard ratio: 8.65, 95% confidence interval: 3.05-24.5, P &lt; .001).

CONCLUSION:

Although our data suggest that achieving seizure freedom should not be the primary goal of AVM treatment, surgical resection may result in improved seizure control compared with radiosurgery for patients who present with seizures. Conversely, in patients without presenting seizures, surgical resection increases the risk of new-onset seizures compared with radiosurgery, but primarily within the early posttreatment period. Surgical resection and radiosurgery result in divergent seizure control rates depending on seizure presentation.

[Intracranial dural arteriovenous fistulae. Experience after 81 cases and literature review]

OBJECTIVES

To analyse the clinical, radiological and therapeutic variables of intracranial dural arteriovenous fistulae (DAVF) treated at our institution, and to assess the validity of the Borden and Cognard classifications and their correlation with the presenting symptoms.

MATERIAL AND METHODS

The DAVF identified were retrospectively analysed. They were classified according to their location, drainage pattern and the Borden and Cognard classifications. We recorded the different treatments, their complications and efficacy.

RESULTS

There were 81DAVF identified between 1975 and 2012. The cavernous sinus (CS) location was the most frequent one. The Borden and Cognard classifications showed an interobserver Kappa index of 0.72 and 0.76 respectively. The odds ratio of aggressive presentation in the presence of cortical venous drainage (CVD) was 19.3 (2.8-132.4). No location, once adjusted by venous drainage pattern, showed significant association with an aggressive presentation. Endovascular transarterial treatment of cavernous sinus DAVF achieved symptomatic improvement of 78%, with a complication rate of 5%. The DAVF of non-CS locations, with CVD, treated surgically were angiographically shown cured in 100% of the cases, with no treatment-related complications.

CONCLUSIONS

The presence of CVD was significantly associated with aggressive presentations. The Borden and Cognard classifications showed little interobserver variability. Endovascular treatment for CS DAVF is safe and relatively effective. Surgical treatment of non-CS DAVF with CVD is safe, effective and the first choice treatment in our environment.

Down but not out

A 20-year-old Hispanic man with Down syndrome presented with progressively worsening headache, fluctuating decreased vision, and bilateral optic disk edema. Magnetic resonance imaging of the head showed an empty sella, and magnetic resonance venography showed thrombosis of left transverse and sigmoid sinuses. Catheter angiography angiogram showed a dural arteriovenous fistula in the wall of left transverse and sigmoid sinuses. The patient underwent Onyx endovascular embolization of the fistula, resulting in its angiographic obliteration, followed by resolution of his clinical signs and symptoms.