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BackgroundTreatment of vein of Galen malformations (VOGMs) has improved greatly since the inception of endovascular treatment. Transvenous embolization (TVE) is an attractive option to achieve complete obliteration.ObjectiveTo review the literature on TVE of VOGM and then analyze our practice’s unique experience and evolving treatment strategies over 30 years.MethodsA retrospective review of our clinical database for patients with the diagnosis of VOGM treated between January 2004 and August 2021 was performed. A literature review of 49 relevant articles was also carried out.ResultsTVE in VOGM has evolved with initial introduction as a transtorcular (TT) approach, which then lost favor to transarterial embolization (TAE). TAE has been considered the more favorable approach in most high-volume centers. In more recent times, the transvenous embolization (TVE) approach has been revisited as a last treatment to achieve a cure after a series of TAE treatments. We presently favor beginning treatment with staged TAE to reduce flow to the lesion and, importantly, shrink the draining vein. This then allows for the performance of TVE with the Chapot pressure cooker technique (CPCT) with coils and liquid embolic embolization.ConclusionsTT TVE itself carries a high degree of risk and is most highly associated with long-term morbidities and mortality. Traditional transfemoral/transjugular TVE approaches are safe and effective in simple fistulas with a small venous pouch; however, we believe that the CPCT is the safest technique as a last-stage treatment for its security in avoiding reflux and obtaining occlusion of the small perforators.

BackgroundEndovascular treatment of intracranial vascular diseases, such as aneurysms, is often challenged by unfavorable vascular anatomy. The Bendit Steerable Microcatheter (Bendit Technologies, Tel Aviv, Israel) has bending and torqueing capabilities designed to improve navigation and stability during device delivery, with or without a guidewire. We describe our preclinical experience with the Bendit 17 and Bendit 21 microcatheters in a rabbit aneurysm model.MethodsBifurcation and side wall aneurysms were created surgically in six New Zealand rabbits. We attempted to navigate Bendit devices through the vasculature and enter the aneurysms without a guidewire. Various positions within the aneurysm were selectively explored. Angiographic imaging was used to visualize catheterization, navigation, vascular manipulations, and placement of coils, stents, and intrasaccular devices.ResultsWe successfully navigated the Bendit microcatheters to all aneurysms without a guidewire. We successfully recanalized a nearly occluded carotid artery and navigated the Bendit through a braided stent. In contrast, we were unable to navigate a comparator device with a guidewire as effectively as the Bendit. Coils were introduced at different locations within the aneurysm and could be pushed, pulled, and repositioned with the Bendit tip. Finally, we used the Bendit to deliver intrasaccular devices designed for terminal aneurysms to treat side wall aneurysms.ConclusionsBendit’s bending and torqueing abilities, combined with its stability in the bent position, enable quick navigation and optimal deployment of devices. Clinical studies are necessary to determine whether these navigation advantages lead to more efficient treatment of intracranial and peripheral aneurysms.

BackgroundIn the last few decades there has been development of innovative therapies for the treatment of craniofacial lymphatic malformations. Percutaneous sclerotherapy has demonstrated efficacy in the management of macrocystic lymphatic lesions, but it is less suitable for microcystic lesions given their size. The gravity-dependent technique is a novel augmentation of standard percutaneous sclerotherapy: the technique enables a sclerosing agent to permeate the small microchannels seen in microcystic lesions that would otherwise be difficult to treat.MethodsBetween 2005 and 2021, 124 patients with microcystic or mixed lymphatic malformations were treated using a novel gravity-dependent sclerotherapy technique. Bleomycin at a maximum dose of 15 IU per session was used as the main sclerosing agent. Fluoroscopy and ultrasound were used to ensure proper positioning of the catheter prior to injecting the sclerosing agent. The response to treatment was assessed clinically and with cross-sectional imaging.ResultsNearly all cases showed significant improvement after the gravity-dependent technique. There have been no permanent complications from sclerotherapy treatment. There was a mild transient adverse effect from bleomycin in one case of erythema and tenderness that lasted several weeks then ameliorated.ConclusionsThe gravity-dependent sclerotherapy technique is a suitable treatment option for microcystic lymphatic malformations.

Endovascular embolization is the mainstay for treatment of infantile dural sinus malformations.1 2 Distal access and flow control are limiting factors in controlled embolization.3–6 The Scepter mini catheter (Microvention, Aliso Viejo, California, USA) is a low-profile, dual-lumen balloon microcatheter designed to provide navigability in small-caliber, tortuous intracranial vessels. In this technical video, we demonstrate the staged embolization of a dural sinus malformation with multiple arteriovenous fistulae using the Scepter mini catheter (video 1). In the newborn patient, embolizations were performed through the parietal branches of the left and right middle meningeal arteries. The catheter easily navigated into the small feeding arteries. No neurological complications occurred due to the procedures. Post-embolization injections demonstrated significant flow reduction into the malformation. Three-month follow-up angiography illustrated resolution of the previously dilated left transverse sinus. Complete obliteration of the dural sinus malformation was achieved in the newborn patient.Video 1Curative embolization in two stages with the Scepter mini balloon microcatheter. ΑP, anteroposterior; CCA, common carotid artery.

BackgroundVessel tortuosity poses a challenge during endovascular treatment of neurovascular lesions. Bendit Technologies (Petah Tikva, Israel) has developed flexible, steerable microcatheters designed with unique bending and torquing capabilities.ObjectiveTo describe our first-in-human trial of Bendit21.MethodsBendit21 was used in our exploratory, prospective, multicenter, open-label, single-arm clinical study, and in two compassionate use cases. Procedures were conducted at four centers in Austria, Germany, Israel, and the United States between May 2021 and March 2022, in patients with neurovascular conditions. The primary endpoints were device-related safety events, successful navigation through the neurovasculature, and, when intended, successful delivery of contrast or therapy.ResultsTwo patients with giant aneurysms were treated successfully under compassionate use approval. The clinical study included 25 patients (mean age: 63.4±11.8 years; 32.0% female). Fourteen patients (56.0%) had aneurysms, two had arteriovenous malformations/fistulas (8.0%), one had a stroke (4.0%), four (16.0%) had intracranial stenosis, and four (16.0%) had other conditions. Bendit21 was used without a guidewire in 12/25 (48.0%) procedures. Bendit21 was successfully navigated through the vasculature without delays or spasms in all cases (100%). Contrast was delivered as intended in 7/7 (100%) cases. Therapeutic devices were delivered successfully with Bendit as intended in 14/18 (77.8%) cases; four deficiencies occurred in three patients with aneurysms, in whom delivery of coils, an intrasaccular device, or a flow diverter was attempted. There were no device-related safety events or mortalities.ConclusionsOur initial clinical experience with the Bendit21 microcatheter demonstrates its usefulness in achieving technical success in patients with challenging neurovascular conditions.

BackgroundNavigable, large diameter aspiration catheters demonstrate markedly improved recanalization rates over smaller lumen devices in suction embolectomy. We evaluated the performance of a novel aspiration catheter system designed to maximize lumen size, and compare it to other commercially available aspiration catheters.MethodsThe 6F R4Q aspiration catheter system comprises a proximal pusher wire of 117 cm length connected to a distal catheter of 25 cm length. When placed through standard guide catheters and into the cerebral circulation, the proximal catheter makes a tight seal between its outer surface and the guide catheter’s inner surface. During aspiration, in vitro flow rates and tip suction force under gentle retraction were compared among 10 commercially available aspiration catheters and the R4Q system.ResultsThe R4Q 6F, 5F, 4F, and 3F catheters achieved flow rates at least 21.9%, 24.7%, 61.9%, and 244.7% greater than the other catheters tested respectively and the R4Q 6F produced a 140.2% higher tip force than a catheter of similar size. Fluid flow rate in the R4Q 6F increased on retraction into the guide catheter, delivering a 58.2% increase from fully extended to fully retracted.ConclusionThe R4Q design demonstrates a substantial increase in aspirated flow rate and suction force due to an increased effective diameter than standard tubular catheter designs tested. The prominent increase in the aspiration parameters measured in vitro supports the potential for improved clinical results during stroke thrombectomy procedures.

BackgroundAnimal experimental studies are crucial for the development of endovascular devices and embolization techniques for intracranial aneurysms. The aim of the study was to describe the surgical creation technique for an aneurysm with a dilated shape and no definable aneurysm neck. The model should be reproducible in size and shape and stay patent over a long period of time. It should constitute a challenge to endovascular therapy and provide a valuable testing environment for new endovascular devices and techniques.MethodsSurgical creation of 30 no-neck aneurysms was attempted in 15 New Zealand White rabbits using a segment of jugular vein, which was transected, longitudinally opened and sutured to the anterior aspect of the common carotid artery. The first 14 aneurysms were used to develop the technique. Once the technique was mastered and the procedure was standardized, 16 consecutive aneurysms were created. For these aneurysms, digital subtraction angiography was employed after a mean of 120 days to confirm size and patency. All aneurysms were evaluated for patency.ResultsOverall aneurysm patency was 93%. Three complications occurred, two of which were related to the vascular anastomosis. Angiographic follow-up showed a median (SD) aneurysm base and height of 6.7 (0.76) mm and 3.2 (0.85) mm), respectively.ConclusionsThis technique allows creation of aneurysms without a neck which are reproducible in size and shape, and which remain patent. The model contributes to the list of aneurysm models fit for evaluation of embolization devices and techniques. It is particularly useful in exploring treatment options for wide-neck aneurysms and aneurysms which presently do not qualify for conventional coiling.

PurposeTo evaluate the clinical outcome of patients with venous malformation (VM) involving the eyelid treated with bleomycin sclerotherapy.MethodsA retrospective review was performed of 18 consecutive patients with VM involving the eyelid who underwent bleomycin sclerotherapy. Patients’ clinical presentation, details of sclerotherapy, and post-sclerotherapy resolution of the lesion as well as any procedure-related complications were evaluated.ResultsTwelve women and six men of mean age 34.3±20.4 years underwent sclerotherapy with bleomycin. Chief complaints were cosmetic disfigurations with or without hemifacial deformity (n=2), pain in engorgement area (n=2), pain and swelling from venous thrombosis (n=2), swelling or engorgement obstructing their eyesight (n=2), or eyelid dysfunction (n=1). The lesions were only in the eyelid in three patients; otherwise they were extended out of the eyelid either superiorly (n=3), laterally (n=8), inferiorly (n=8), and/or posteriorly to the orbit (n=8) to various extents. Conjunctival involvement was present in 13 patients. 14 patients had received prior treatments including surgery, laser therapy, or non-bleomycin sclerotherapy. With an average three sessions of bleomycin sclerotherapy (average total dose 34.5 mg), more than 80% shrinkage was observed in seven patients (38.9%), 50–80% shrinkage in eight patients (44.4%), and 30–50% shrinkage in two patients (11.1%). One patient had recurrence, which was successfully treated again with bleomycin. No procedure-related complications were noted.ConclusionsThe use of bleomycin appears to be a simple, safe, and effective treatment for venous malformations involving the eyelid, avoiding more elaborate and challenging surgical or laser interventions, and is even effective in full thickness lesions.

Introduction Endovascular embolization of intracranial vascular malformations with N-butyl cyanoacrylate (nBCA) using a detachable tip microcatheter allows prolonged injection and decreases the risk of catheter retention. Methods Between March and December 2013, the Apollo 1.5 cm detachable tip microcatheter was used in five patients after being approved by both the Food and Drug Administration and the institutional review board as a compassionate use device. Nine pedicles were embolized and the follow-up ranged from 1 to 3 months. Results Five of the nine catheter tips detached. The length of reflux was not directly associated with the detachment of the distal tip. There were no cases of premature microcatheter detachment during navigation, manipulation with multiple microguidewire reintroduction and guidance. There was no leak of embolic agent at the detachment zone. Follow-up showed the detached tip to be stable without migration. Conclusions A detachable tip microcatheter offers an advance in the safety and effectiveness of nBCA embolization. Catheter retrieval becomes more controlled and less traumatic. Our initial experience is encouraging, and more experience is needed to categorically ascertain its safety and efficacy.

BackgroundIntracranial vascular malformations in children are being addressed through a variety of treatment modalities including open surgery, external beam radiation, and image-guided neuroendovascular procedures. These patients often receive multiple treatments and incur serial exposures to ionizing radiation which has been linked to tumor development in population-based data.ObjectiveThis study quantifies the effect of collimation on exposures from single procedures and over patient lifetimes to estimate excess risk of lifetime tumor development.Methods215 patients aged 0–21 years from a single center took part in the study. Radiation exposure from neuroendovascular procedures was tabulated and converted to brain doses using modeled data and extrapolated to risk ratios using results of population-based estimates found in the literature.ResultsLifetime and per procedure risk was highest in patients with brain arteriovenous malformations, brain arteriovenous fistulas, and vein of Galen malformations, a reflection of our institutional referral patterns. Across all pathologies the per procedure excess relative risk decreased from 13.4 to 2.3 when full collimation was employed. Lifetime excess relative risk decreased from 49.0 to 7.7 for full collimation.ConclusionsThis is the first study to quantify the effect of collimation on lifetime and per procedure risk of tumor development in a pediatric population. In addition to collimation, technical and operator-based aspects of the neurointerventional suite are discussed to further reduce patient exposure without sacrificing image quality.

BackgroundOcclusion of canine bifurcation and sidewall aneurysms was undertaken with a new liquid embolic agent (PHIL 35) assisted by a high-density partially retrievable stent (FRED) with preservation of the carotid artery.MethodsThree dogs were used as acute preparations for development of the technique and two were used for chronic studies lasting 90 days. In one animal we intentionally did not completely fill the aneurysm to determine the long-term results of incomplete treatment. The degree of occlusion, carotid artery compromise, and dislodgement and/or migration of embolic material in treated aneurysms were assessed.ResultsAll aneurysms planned for complete obliteration were totally occluded successfully. By design, we partially occluded one aneurysm. In this aneurysm, angiography performed at 30 days revealed less filling, but at 90 days it had persistent small residual filling. We did not detect any distal embolization during the injection and no angiographic occlusions, change in configuration, or delayed migration of the embolic material were found. In the inspected stent, no foreign material was noted. In four animals we successfully removed the stent with preservation of the integrity of the carotid artery. In the fifth we intentionally left both stents deployed.ConclusionsWe have developed a new treatment for cerebral aneurysms using a combination of a retrievable stent and a new liquid embolic agent.

Purpose To develop a simple and reproducible grading system to assess the outcome of treatment for LM. Methods and technique The availability of noninvasive MRI imaging lends itself to a reliable and reproducible ability to compare pretreatment, during treatment and after treatment imaging, and the burden of disease that remains after treatment Materials 20 consecutive cases of H&N LM before and after treatment, was reviewed by 2 independent diagnostic neuroradiologists using our 7 points grading system 1: Complete disappearance 2: Significant near-complete disappearance. 3: Significant decrease in the residual malformation. 4: Decrease of the malformation at one region but increase in another area. 5: Decrease of the malformation but presence of a new area of noncystic changes 6: No change or minimal change. 7: Worsening of pretreatment imaging. Results Both scored the same on all 20 exams. Conclusion Our grading system is simple, and reproducible in LM throughout the body, permitting objective comparison between different treatments. Disclosures A. Berenstein: None.

Purpose To describe the use of bleomycin in a foam preparation and or undiluted in slow flow vascular lesions that involve the conjunctiva as the sole treatment Material and methods 5 patients with venous malformations, and 2 with lymphatic malformations involving the conjunctiva were treated with various combination bleomycin injections in to the lesion under direct puncture, using various needles and or angio-catheters; and monitored with US or DSA. Results There was significant improvement, or near total resolution in all patients with a follow up of up to 3 years, there were no complications Conclusions The use of bleomycin in various forms appears as a simple, safe and very effective treatment for low flow vascular lesions involving the conjunctiva, avoiding more elaborated and challenging surgical intervention. Disclosures A. Berenstein: None.

Purpose To describe a novel gravity technique of sclerotherapy for microcytic LM. Methods and technique A 23 angiocatheter connected to a tubing field with the sclerosing agent, is passed through and through the lesion, the angiocatheter is slowly withdraw, with the tubing at 15 cm of H2O, as a microchannel is entered, the fluid will permeate the microchannel. As the channel(s) fill the tubing needs to be further elevated and that part of the lesion is field, the angiocatheter is slowly further withdrawn, and as a new channel is entered the fluid column starts advancing. Materials From 2009–2015 in 154 patients with LM, 34 were microcytic, (500 micron range), treated using the gravity technique, with Doxycycline and or Bleomycin Results Significant improvement was noted in most patients, usually towards the 2 or 3rd treatment, both clinically and by cross section imaging. No complications occurred. Conclusion Our gravity technique permits treating lesions with true microcytic channels in a safe and effective manner. Disclosures A. Berenstein: None.

Background The development of de novo dural arteriovenous fistula(s) following endovascular embolization of a prior high-flow pial arteriovenous fistula (PAVF) has not previously been reported and the natural history is unknown. The anatomic basis, pathophysiologic mechanism, management and outcome are discussed. Methods Treatment-completed congenital PAVFs treated at our center between January 2005 and August 2011 were analyzed retrospectively. Among 16 cases of PAVFs treated by endovascular embolization, four developed de novo dural arteriovenous fistulas during treatment or on follow-up that were not present before treatment. Information was collected from the clinical case records, imaging by MRI on presentation and during follow-up, all angiographic images and records during each of the procedures and during follow-up. Results The time interval between the last embolization and identification of a dural fistula ranged from 3 to 14 months. Ten fistulas were identified in four patients, seven of which were embolized, four with glue, two with Onyx18 and one with absolute alcohol. None recanalized, while one patient developed fistula in an adjacent location that was subsequently treated with radiosurgery. Not all fistulas need treatment; small fistulas with a minimal flow can safely be observed. Conclusions De novo dural fistulas following endovascular embolization of high-flow PAVFs is not an uncommon development. They are mostly asymptomatic and develop anywhere along the drainage of the fistula, maturing over time and diagnosed during follow-up studies, emphasizing the need for follow-up angiography. They can be effectively treated by endovascular embolization. Localized refractory dural fistulas can be dealt with by radiosurgery.

Introduction Pial arteriovenous fistulas (AVF) are vascular disorder of the brain consisting of a direct connection between arteries and veins without a nidus located in the subpial space, and are frequently associated with venous varix. Materials and Results This study reviewed a series of 16 children with congenital pial AVF, treated between January 2005 and August 2011. All cases presented before 5 years of age and the mode of presentation varied with age. Fourteen had a single fistula while two had multiple fistulas, one among them had cutaneous features suggestive of RASA1 mutation. MRI is the preferred initial imaging, to demonstrate anatomical location, feeders, venous varix and regional, hemispheric or diffuse cerebralmalacia. Digital subtraction angiography performed during the first therapeutic attempt showed venous varix along with arterial enlargement as the most common angio-architecture. All cases were embolized with N-butyl-cyanoacrylate (NBCA) with or without coiling of the venous sac to attain flow control. Hypotension and a higher concentration of glue were used to aid controlled glue injections. Dural AVF and reactive angiogenesis are not uncommon sequlae found on follow-up angiogram. Outcomes were excellent in 75% and good in 19%. Conclusion Congenital pial AVF are caused by a missed step in vascular development during the early embryonic stage. Transarterial endovascular embolizaiton using NBCA with or without using coils to attain flow control is the treatment of choice, with low morbidity. The efficacy of treatment is high as demonstrated by the high cure rate. Follow-up angiogram is mandatory to look for recanalization, reactive angiogenesis and denovo dural AVF development.