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Juan Pablo Cruz, Rene van Dijk, Timo Krings, and Ronit Agid

Dural arteriovenous fistulas (DAVFs) of the cavernous sinus are acquired arteriovenous shunts between the dural branches of the internal and external carotid arteries and the cavernous sinus. These fistulas may present with cortical venous reflux, but more commonly drain antegradely toward the superior ophthalmic vein (SOV). Transvenous embolization is the most common endovascular treatment, but in some cases transvenous access to the compartment of the shunt may not be possible. In cases with no corticovenous reflux, manual compression of the SOV is an excellent alternative treatment, which is well known but rarely reported in the literature. The authors describe a series of 3 cavernous DAVFs with anterior drainage treated successfully by intermittent manual compression of the SOV.

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Ronit Agid and Karel Terbrugge

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Kar Ming Leung, Ronit Agid, and Karel Terbrugge

✓ Patients with hereditary hemorrhagic telangiectasia (HHT) are at risk for the development of cerebral arteriovenous malformations (AVMs). The authors report a case of a spontaneously regressing cerebral AVM in a patient with HHT. The lesion was diagnosed on the basis of findings on screening magnetic resonance imaging and regressed completely before any treatment was undertaken. The spontaneous regression of cerebral AVMs is a rare and poorly understood phenomenon. Only one other instance of spontaneous regression of a cerebral AVM in a patient with HHT has been reported in the literature. The authors compare angiographic and clinical features in previously reported cases of spontaneous regression of cerebral AVMs with those in the present case to determine the characteristics common to this phenomenon.

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Ann Mansur, Alex Kostynskyy, Timo Krings, Ronit Agid, Ivan Radovanovic, and Vitor Mendes Pereira

OBJECTIVE

The aim of this study was to 1) compare the safety and efficacy of acute targeted embolization of angiographic weak points in ruptured brain arteriovenous malformations (bAVMs) versus delayed treatment, and 2) explore the angioarchitectural changes that follow this intervention.

METHODS

The authors conducted a retrospective analysis of a prospectively acquired database of ruptured bAVMs. Three hundred sixteen patients with ruptured bAVMs who presented to the hospital within 48 hours of ictus were included in the analysis. The first analysis compared clinical and functional outcomes of acutely embolized patients to those with delayed management paradigms. The second analysis compared these outcomes of patients with acute embolization to those with angiographic targets who did not undergo acute embolization. Finally, a subset of 20 patients with immediate postembolization angiograms and follow-up angiograms within 6 weeks of treatment were studied to determine the angioarchitectural changes after acute targeted embolization. Kaplan-Meier curves for survival between the groups were devised. Multivariate logistical regression analysis was conducted.

RESULTS

There were three deaths (0.9%) and an overall rerupture rate of 4.8% per year. There was no statistical difference in demographic variables, mortality, and rerupture rate between patients with acute embolization and those with delayed management. Patients with acute embolization were more likely to present functionally worse (46.9% vs 69.8%, modified Rankin Scale score 0–2, p = 0.018) and to require an adjuvant therapy (71.9% vs 26.4%, p < 0.001). When comparing acutely embolized patients to those nonacutely embolized angiographic targets, there was a significant protective effect of acute targeted therapy on rerupture rate (annual risk 1.2% vs 4.3%, p = 0.025) and no difference in treatment complications. Differences in the survival curves for rerupture were statistically significant. Multivariate analyses significantly predicted lower rerupture in acute targeted treatment and higher rerupture in those with associated aneurysms, deep venous anatomy, and higher Spetzler-Martin grade. All patients with acute embolization experienced complete obliteration of the angiographic weak point with various degrees of resolution of the nidus; however, some had spontaneous recurrence of their bAVM, while others had spontaneous resolution over time. No patients developed new angiographic weak points.

CONCLUSIONS

This study demonstrates that acute targeted embolization of angiographic weak points, particularly aneurysms, is technically safe and protective in the early phase of recovery from ruptured bAVMs. Serial follow-up imaging is necessary to monitor the evolution of the nidus after targeted and definitive treatments. Larger prospective studies are needed to validate these findings.

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Vitor Mendes Pereira, Patrick Nicholson, Nicole M. Cancelliere, Xiao Yu Eileen Liu, Ronit Agid, Ivan Radovanovic, and Timo Krings

OBJECTIVE

Geographic factors prevent equitable access to urgent advanced neuroendovascular treatments. Robotic technologies may enable remote endovascular procedures in the future. The authors performed a translational, benchtop-to-clinical study to evaluate the in vitro and clinical feasibility of the CorPath GRX Robotic System for robot-assisted endovascular neurointerventional procedures.

METHODS

A series of bench studies was conducted using patient-specific 3D-printed models to test the system’s compatibility with standard neurointerventional devices, including microcatheters, microwires, coils, intrasaccular devices, and stents. Optimal baseline setups for various procedures were determined. The models were further used to rehearse clinical cases. Subsequent to these investigations, a prospective series of 6 patients was treated using robotic assistance for complex, wide-necked intracranial saccular aneurysms between November 2019 and February 2020. The technical success, incidence of periprocedural complications, and need for conversion to manual procedures were evaluated.

RESULTS

The ideal robotic setup for treatment of both anterior and posterior circulation aneurysms was determined to consist of an 80-cm guide catheter with a 115-cm-long intermediate catheter, a microcatheter between 150 and 170 cm in length, and a microwire with a minimum length of 300 cm. All coils, intrasaccular devices, and stents tested were compatible with the system and could be advanced or retracted safely and placed accurately. All 6 clinical procedures were technically successful, with all intracranial steps being performed robotically with no conversions to manual intervention or failures of the robotic system. There were no procedure-related complications or adverse clinical outcomes.

CONCLUSIONS

This study demonstrates the feasibility of robot-assisted neurointerventional procedures. The authors’ results represent an important step toward enabling remote neuroendovascular care and geographic equalization of advanced endovascular treatments through so-called telestroke intervention.

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Ronit Agid, Karel TerBrugge, Georges Rodesch, Tommy Andersson, and Michael Söderman

Object

Dural arteriovenous fistulas (DAVFs) of the anterior cranial fossa are rare lesions that can cause intracranial hemorrhage. Authors of previous reports mostly have described open surgical treatment for this fistula type. The authors' purpose in the present study was to describe their experience with anterior cranial fossa DAVFs, including their endovascular treatment.

Methods

All patients with anterior cranial fossa DAVFs diagnosed and treated in 3 separate institutions during the last 23 years were retrospectively identified. Clinical charts, imaging studies, and procedural notes were evaluated.

Results

Twenty-four patients (22 males and 2 females), ranging in age from 3 to 77 years, harbored 24 DAVFs in the anterior cranial fossa. Eleven patients were primarily treated with surgical disconnection and 2 with radiosurgery. Eleven patients were treated endovascularly; 7 of these patients (63.6%) were cured. In 4 cases of failed embolization, final disconnection was achieved through surgery. In fact, surgery was effective in disconnecting the fistula in 100% of cases. All endovascular procedures consisted of transarterial injections of diluted glue (N-butyl cyanoacrylate [NBCA]), and there were no complications. Brain edema developed around the venous pouch and confusion was apparent after venous disconnection in 1 surgically treated patient. No patient suffered a hemorrhage during the follow-up period.

Conclusions

Disconnection of an anterior cranial fossa DAVF by using transarterial catheterization through the ophthalmic artery and subsequent injection of NBCA is possible with a reasonable success rate and low risk for complications. In patients with good vascular access this procedure could be the treatment of choice, to be followed by open surgery in cases of embolization failure.

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Susanna Bacigaluppi, Amir R. Dehdashti, Ronit Agid, Timo Krings, Michael Tymianski, and David J. Mikulis

The aim of this review was to evaluate the imaging tools used in diagnosis and perioperative assessment of moyamoya disease, with particular attention to the last decade.

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Hengwei Jin, Stephanie Lenck, Timo Krings, Ronit Agid, Yibin Fang, Youxiang Li, Alex Kostynskyy, Michael Tymianski, Vitor Mendes Pereira, and Ivan Radovanovic

OBJECTIVE

The goal of this study was to describe changes in the angioarchitecture of brain arteriovenous malformations (bAVMs) between acute and delayed cerebral digital subtraction angiography (DSA) obtained after hemorrhage, and to examine bAVM characteristics predicting change.

METHODS

This is a retrospective study of a prospective institutional bAVM database. The authors included all patients with ruptured bAVMs who had DSA in both acute and delayed phases, with no interval treatment of their bAVM, between January 2000 and April 2017. The authors evaluated the existence or absence of angioarchitectural changes. Demographic data, radiological characteristics of hemorrhages, and angioarchitectural features of the bAVMs of the two patients’ groups were analyzed. Univariate and multivariate logistic analyses were performed to identify predictors of angioarchitectural change.

RESULTS

A total of 42 patients were included in the series. Seventeen (40.5%) patients had angioarchitectural changes including bAVM only visible on the delayed DSA study (n = 8), spontaneous thrombosis of the AVM (n = 3), or alteration of the size or the opacification of the nidus (n = 6). The factors associated with angioarchitectural changes were a small nidus (3.8 ± 7.9 ml vs 6.1 ± 9.5 ml, p = 0.046), a superficial location (94.1% vs 5.9%, p = 0.016), and a single superficial draining vein (58.8% vs 24.0%, p = 0.029).

CONCLUSIONS

Angioarchitectural changes can be seen in 40% of ruptured bAVMs between the acute- and delayed-phase DSA. A small nidus, a superficial location, and a single superficial draining vein were statistically associated with the occurrence of angioarchitectural changes. These changes included either enlargement or spontaneous occlusion of the bAVM, as well as subsequent diagnosis of a bAVM following an initial negative DSA study.

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Marlise P. dos Santos, Jingwen Zhang, Diana Ghinda, Rafael Glikstein, Ronit Agid, Georges Rodesch, Donatella Tampieri, and Karel G. terBrugge

Intraspinal tumors comprise a large spectrum of neoplasms, including hemangioblastomas, paragangliomas, and meningiomas. These tumors have several common characteristic imaging features, such as highly vascular mass appearance in angiography, hypointense rim and serpentine flow voids in MRI, and intense enhancement after intravenous contrast administration. Due to their rich vascularity, these tumors represent a special challenge for surgical treatment. More recently, the surgical treatment of intraspinal vascular tumors has benefited from the combination of endovascular techniques used to better delineate these lesions and to promote preoperative reduction of volume and tissue blood flow. Endovascular embolization has been proven to be a safe procedure that facilitates the resection of these tumors; hence, it has been proposed as part of the standard of care in their management.

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Sean T. O’Reilly, Eef Jacobus Hendriks, Marie-Christine Brunet, Ze’ev Itsekson, Rabab Al Shahrani, Ronit Agid, Patrick Nicholson, Karel terBrugge, Ivan Radovanovic, and Timo Krings

OBJECTIVE

Spinal dural arteriovenous fistulas (SDAVFs) typically represent abnormal shunts between a radiculomeningeal artery and radicular vein, with the point of fistulization classically directly underneath the pedicle of the vertebral body, at the dural sleeve of the nerve root. However, SDAVFs can also develop in atypical locations or have more than one arterial feeder, which is a variant of SDAVF. The aim of this study was to describe the incidence and multidisciplinary treatment of variant SDAVFs in a single-center case series.

METHODS

Following institutional review board approval, the authors retrospectively analyzed their prospectively maintained database of patients with SDAVFs who presented between 2008 and 2020. For all patients, spinal digital subtraction angiograms were reviewed and variant SDAVFs were identified. Variant types of SDAVFs were defined as cases in which the fistulous point was not located underneath the pedicle. Patient demographics, angiographic features, clinical outcomes, and treatment modalities were assessed.

RESULTS

Of 59 patients with SDAVFs treated at the authors’ institution, 4 patients (6.8%) were identified as having a variant location of the shunt zone, pinpointed on the dura mater at the intervertebral level, further posteriorly within the spinal canal. In 3 cases (75%), a so-called bimetameric arterial supply was demonstrated.

CONCLUSIONS

Recognition of the variant type of SDAVF is crucial for management, as correct localization of the fistulous point and bimetameric supply are critical for successful surgical disconnection, preventing delay in achieving definitive treatment.