The use of Onyx for embolization of central nervous system arteriovenous lesions in pediatric patients

Pediatric Cerebral Vascular Malformations : Current and Future Perspectives

Intracranial vascular malformations typically encountered by pediatric neurosurgeons include arteriovenous malformations, vein of Galen malformations and cavernous malformations. While these remain amongst some of the most challenging lesions faced by patients and caregivers, the past decade has produced marked advances in the understanding of the pathophysiology of these conditions, with concomitant innovations in treatment. This article will highlight present and future perspectives relevant to these diseases, with a focus on an emerging approach utilizing disease-specific mutations to develop a novel taxonomy for these conditions.

Outcomes of endovascular embolization for Vein of Galen malformations: An individual participant data meta-analysis

Introduction

Understanding outcomes after Vein of Galen malformation (VOGM) embolization has been limited by small sample size in reported series and predominantly single center studies. To address these limitations, we perform an individual-participant meta-analysis (IPMA) to identify risk factors associated with all-cause mortality and clinical outcome after VOGM endovascular embolization.

Methods

We performed a systematic review and IPMA of VOGM endovascular outcomes according to PRISMA guidelines. Individual patient characteristics including demographic, intra/post-operative adverse events, treatment efficacy (partial or complete occlusion), and clinical outcome were collected. Mixed-effects logistic regression with random effects modeling and Bonferroni correction was used (p ≤ 0.003 threshold for statistical significance). The primary and secondary outcomes were all-cause mortality and poor clinical outcome (moderate/severe developmental delay or permanent disabling injury), respectively. Data are expressed as (mean ± standard deviation (SD)) or (odds ratio (OR), 95% confidence interval (CI), I 2, p-value).

Results

Thirty-five studies totaling 307 participants quantifying outcomes after endovascular embolization for VOGM were included. Follow up time was 42 (±57) months. Our analysis contained 42% neonates (<1 month) at first embolization, 45% infants (1 month ≤2 years), and 13% children (>2 years). Complete occlusion was reported in 48% of participants. Overall all-cause mortality was 16%. Overall, good clinical outcome was achieved in 68% of participants. First embolization as a neonate [OR = 6.93; 95% CI (1.99-24.08); I 2 < 0.01; p < 0.001] and incomplete embolization [OR = 10.87; 95% CI (1.86-63.55); I 2 < 0.01; p < 0.001] were associated with mortality. First embolization as a neonate [OR = 3.24; 95% CI (1.47-7.15); I 2 < 0.01; p < 0.001], incomplete embolization [OR = 5.26; 95% CI (2.06-13.43); I 2 < 0.01; p < 0.001], and heart failure at presentation [OR = 3.10; 95% CI (1.03-9.33); I 2 < 0.01; p = 0.002] were associated with poor clinical outcomes. Sex, angioarchitecture of lesion, embolization approach (transvenous vs. transarterial), and single or multistage embolization were not associated with mortality or clinical outcome.

Conclusions

We identify incomplete VOGM embolization independently associated with mortality and poor clinical outcome. While this study provides the highest level of evidence for VOGM embolization to date, prospective multicenter studies are needed to understand the optimal treatment strategies, outcomes, and natural history after VOGM embolization.

Tantalum-specific contrast-to-noise ratio or conventional detector dose-driven exposure control in angiography: radiation dose and image quality evaluation in a porcine model

Background

The aim of this animal study was to compare the fluoroscopic image quality (IQ) and radiation dose between a tantalum (Ta)-specific contrast-to-noise ratio-driven exposure control (Ta-CEC) and a detector dose-driven exposure control (DEC) in abdominal angiography.

Methods

Nine angiography scenarios were created in seven anaesthetised pigs using Ta-based embolisation material during percutaneous liver and kidney intervention. Fluoroscopic images were acquired using three DEC protocols with different dose levels and Ta-CEC protocols with different IQ levels, sampled in small steps. Polymethyl-methacrylate and aluminium plates were used to simulate attenuation of three water equivalent thicknesses (WET). Three blinded readers evaluated the IQ of DEC and dose equivalent Ta images and selected the Ta-IQ equivalent image corresponding to the DEC image.

Results

Interobserver agreement for the IQ assessment was 0.43 for DEC, 0.56 for Ta-CEC and for the assessment of incident air kerma at the interventional reference point (K_a,r) for the Ta-IQ equivalent image 0.73. The average IQ of the dose equivalent Ta images was superior compared to the DEC images (p < 0.001) and also for every WET (26, 31, or 36 cm) and dose level (p ≤ 0.022). The average K_a,r for the Ta-IQ equivalent images was 59 ± 16% (mean ± standard deviation) lower compared to the DEC images (p < 0.001).

Conclusions

Compared to DEC, Ta-CEC significantly improved the fluoroscopic depiction of Ta, while maintaining the K_a,r. Alternatively, the K_a,r can be significantly reduced by using Ta-CEC instead of DEC, while maintaining equivalent IQ.

Review on the current treatment status of vein of Galen malformations and future directions in research and treatment

INTRODUCTION

Vein of Galen malformations (VOGMs) represent a rare pathologic entity with often catastrophic natural history. The advances in endovascular treatment in recent years have allowed for a paradigm shift in the treatment and outcome of these high-flow shunts, even though their pathogenetic mechanisms and evolution remain in part obscure.

AREAS COVERED

The overall management of VOGMs requires a tailored case-to-case approach, starting with in utero detection and reserving endovascular treatment for indicated cases. Lately, the advances in translational research with whole-genome sequencing and the coupling with cellular-level hemodynamics attempt to shed more light in the pathogenesis and evolution of these lesions. At the same time the advances in endovascular techniques allow for more safety and tailored technical strategy planning. Furthermore, the advances in MRI techniques allow a better understanding of their vascular anatomy. In view of these recent advances and by performing a PUBMED literature review of the last 15 years, we attempt a review of the evolutions in the imaging, management, endovascular treatment and understanding of underlying mechanisms for VOGMs.

EXPERT OPINION

The progress in the fields detailed in this review appears very promising in better understanding VOGMs and expanding the available therapeutic arsenal.

Impact of a contrast-to-noise ratio driven and material specific exposure control on image quality and radiation exposure in angiography

Conventional detector-dose driven exposure controls (DEC) do not consider the contrasting material of interest in angiography. Considering the latter when choosing the acquisition parameters should allow for optimization of x-ray quality and consecutively lead to a substantial reduction of radiation exposure. Therefore, the impact of a material-specific, contrast-to-noise ratio (CNR) driven exposure control (CEC) compared to DEC on radiation exposure was investigated. A 3D-printed phantom containing iron, tantalum, and platinum foils and cavities, filled with iodine, barium, and gas (carbon dioxide), was developed to measure the CNR. This phantom was placed within a stack of polymethylmethacrylate and aluminum plates simulating a patient equivalent thickness (PET) of 2.5-40 cm. Fluoroscopy and digital radiography (DR) were conducted applying either CEC or three, regular DEC protocols with parameter settings used in abdominal interventions. CEC protocols where chosen to achieve material-specific CNR values similar to those of DEC. Incident air kerma at the reference point(K_a,r), using either CEC or DEC, was assessed and possible K_a,r reduction for similar CNR was estimated. We show that CEC provided similar CNR as DEC at the same or lower K_a,r. When imaging barium, iron, and iodine K_a,r was substantially reduced below a PET of 20 cm and between 25 cm and 30 cm for fluoroscopy and Dr When imaging platinum and tantalum using fluoroscopy and DR and gas using DR, the K_a,r reduction was substantially higher. We estimate the K_a,r reduction for these materials between 15% and 84% for fluoroscopy and DR between 15% and 93% depending on the PET. The results of this study demonstrate a high potential for skin dose reduction in abdominal radiology when using a material-specific CEC compared to DEC. This effect is substantial in imaging materials with higher energy K-edges, which is beneficial, for example, in long-lasting embolization procedures with tantalum-based embolization material in young patients with arterio-venous malformations.

Transvenous Pressure Monitoring Guides Endovascular Treatment of Vein of Galen Malformation: A Technical Note

INTRODUCTION

Vein of Galen malformations (VGMs) are complex congenital arteriovenous malformations that generally require serial endovascular treatment sessions to slowly correct the high-flow fistulous connections that cause increased venous pressures and ultimately lead to the classic presentations of heart failure, hydrocephalus, and intracranial hemorrhages. Despite the advances in endovascular technology and embolic materials, the resolution of embolization is often limited to the subjective view of diminished flow on angiograms.

CASE REPORT

An 8-month-old patient with a VGM developed clinical signs of heart failure and growing head circumference with ventriculomegaly. The patient was treated endovascularly with a transvenous approach for coil embolization while undergoing continuous monitoring of the post-malformation venous pressures. The arterial and venous systolic blood pressures (SBP) were collected at serial time points and used to measure estimated 95% confidence interval bounds for arteriovenous SBP gradients and determine when sufficient coil embolization and flow reduction was thought to be achieved.

CONCLUSION

The transvenous pressure monitoring demonstrated progressively increasing pressure gradients between the arterial and venous systems that correlated with the degree of flow reduction on angiographic runs. The patient underwent successful coil embolization of the VGM and had improvement of heart failure and ventricular size in follow-up at 8-month post-op. This provides a novel technique to introduce an objective measurement that can guide the embolization of a VGM.

Treatment options and long-term outcomes in pediatric spinal cord vascular malformations: a case report and review of the literature

A 16-month-old female was admitted for prolonged fever, gait ataxia, and neurogenic bowel and bladder. Neurological exam was significant for decreased sensory and motor functions in bilateral lower extremities. Initial MRI showed a thoracic spine hematoma and diagnostic angiogram revealed a large AVM and aneurysm. The patient underwent surgical resection of the hematoma and AVM, as well as clipping and later endovascular coiling of the aneurysm. Due to significant hemorrhage perioperatively, she developed spastic paraplegia improved by baclofen and onabotulinumtoxin A injections. The aims of this paper were to conduct a systematic review of the literature on pediatric spinal cord vascular malformations and analyze trends in treatment options and long-term neurological outcomes. PubMed searches were conducted using keywords "pediatric spinal vascular malformation" and "pediatric spinal AVM", yielding 34 results after abstract screening and cross-reference. Endovascular embolization was determined to have better long-term outcomes, with 10/19 (52.6%) patients with postoperative complications associated with open vascular surgeries. Open versus endovascular surgical decisions can be difficult with unique spinal AVM pathologies in pediatric patients. Important considerations such as size, location, neurological deficits, and risk of rupture are important factors to consider in treating these patients. We recommend endovascular treatment as a first-line approach due to lower risk of hemorrhage and postoperative deficits.

Hemorrhagic Cerebrovascular Pathology in the Pediatric Population

Hemorrhagic cerebrovascular disease in the pediatric population can have devastating and long-term effects. Progress in the fields of genetics, neuroimaging, pharmacology, and surgical techniques has led to improved diagnosis and management of pediatric cerebrovascular diseases. In this review we discuss the current etiologies and medical and surgical treatments of hemorrhagic cerebrovascular pathology affecting infants and children. A special emphasis is placed on neuroendovascular treatment options. Increased knowledge about this unique pathology and the medical and therapeutic options will empower practitioners to more quickly and accurately identify and accurately treat hemorrhagic diseases in the pediatric population.

Bringing high-grade arteriovenous malformations under control: clinical outcomes following multimodality treatment in children

OBJECTIVE

Brain arteriovenous malformations (AVMs) consist of dysplastic blood vessels with direct arteriovenous shunts that can hemorrhage spontaneously. In children, a higher lifetime hemorrhage risk must be balanced with treatment-related morbidity. The authors describe a collaborative, multimodal strategy resulting in effective and safe treatment of pediatric AVMs.

METHODS

A retrospective analysis of a prospectively maintained database was performed in children with treated and nontreated pediatric AVMs at the University of California, San Francisco, from 1998 to 2017. Inclusion criteria were age ≤ 18 years at time of diagnosis and an AVM confirmed by a catheter angiogram.

RESULTS

The authors evaluated 189 pediatric patients with AVMs over the study period, including 119 ruptured (63%) and 70 unruptured (37%) AVMs. The mean age at diagnosis was 11.6 ± 4.3 years. With respect to Spetzler-Martin (SM) grade, there were 38 (20.1%) grade I, 40 (21.2%) grade II, 62 (32.8%) grade III, 40 (21.2%) grade IV, and 9 (4.8%) grade V lesions. Six patients were managed conservatively, and 183 patients underwent treatment, including 120 resections, 82 stereotactic radiosurgery (SRS), and 37 endovascular embolizations. Forty-four of 49 (89.8%) high-grade AVMs (SM grade IV or V) were treated. Multiple treatment modalities were used in 29.5% of low-grade and 27.3% of high-grade AVMs. Complete angiographic obliteration was obtained in 73.4% of low-grade lesions (SM grade I-III) and in 45.2% of high-grade lesions. A periprocedural stroke occurred in a single patient (0.5%), and there was 1 treatment-related death. The mean clinical follow-up for the cohort was 4.1 ± 4.6 years, and 96.6% and 84.3% of patients neurologically improved or remained unchanged in the ruptured and unruptured AVM groups following treatment, respectively. There were 16 bleeding events following initiation of AVM treatment (annual rate: 0.02 events per person-year).

CONCLUSIONS

Coordinated multidisciplinary evaluation and individualized planning can result in safe and effective treatment of children with AVMs. In particular, it is possible to treat the majority of high-grade AVMs with an acceptable safety profile. Judicious use of multimodality therapy should be limited to appropriately selected patients after thorough team-based discussions to avoid additive morbidity. Future multicenter studies are required to better design predictive models to aid with patient selection for multimodal pediatric care, especially with high-grade AVMs.

Inline Balloon Occlusion-Assisted Delivery of Ethylene Vinyl Alcohol Copolymer for Peripheral Arterial Applications: A Multicenter Case Series

PURPOSE

To assess the feasibility, safety, and efficacy of balloon-assisted delivery of ethylene vinyl alcohol copolymer (EVOH) for a range of peripheral arterial applications.

MATERIALS AND METHODS

Six academic medical centers entered retrospective data on 46 consecutive patients (27 men, 19 women; ages, 11-94 y; mean age, 50.3 y) who underwent 60 balloon-assisted EVOH procedures. The cohort was restricted to procedures involving peripheral, nonneural arteries 1-5.5 mm in diameter. Clinical indications included a wide range of vascular pathologic conditions (most commonly arteriovenous malformations [n = 20], renal angiomyolipomas [n = 8], and acute hemorrhage [n = 9]) and targeted visceral and musculoskeletal peripheral arteries. Data collected included sex, age, clinical indication, arterial pathology, arteries embolized, type of occlusion balloon microcatheter, type and concentration of EVOH agent, effectiveness as an embolic backstop, vessels protected, adequacy of EVOH cast penetration, catheter extraction, nontarget embolization, and complications.

RESULTS

Balloon occlusion prevented EVOH reflux in 59 of 60 procedures (98.3%). Nontarget EVOH embolization occurred in 2 procedures (3.3%). Adequate EVOH cast penetration and complete filling of the target pathologic structure were seen in 57 of 60 procedures (95%). Balloon deflation and uneventful extraction occurred in all procedures; small EVOH fragments detached into target arteries in 2 cases. One major (1.7%) and 2 minor (3.3%) complications occurred.

CONCLUSIONS

Balloon-assisted EVOH embolization of peripheral arteries is feasible, safe, effective, and versatile. The primary advantage of balloon-assisted EVOH embolization is the ability to apply more injection pressure to advance the EVOH cast assertively into the pathologic structure(s).

First Line Onyx Embolization in Ruptured Pediatric Arteriovenous Malformations : Safety and Efficacy

PURPOSE

Brain arteriovenous malformations (bAVM) are the main cause of pediatric intracerebral hemorrhage (pICH). Embolization with Onyx (ev3, Irvine, CA, USA) in children with ruptured bAVM has been infrequently reported. The aim of this study was to assess the safety and efficacy profile of Onyx embolization as first line endovascular treatment of ruptured pediatric bAVMs.

METHODS

Children with non-traumatic pICH due to bAVM rupture at a pediatric quaternary care center were prospectively enrolled in a registry and retrospectively analyzed between 2013 and 2018. Clinical and demographic data, treatment modalities and clinical imaging follow-up were retrieved, and detailed procedural data were retrospectively assessed by two investigators. The safety (procedural morbidity and mortality) and efficacy (obliteration and interval rebleeding) were evaluated.

RESULTS

In this study 29 children treated for a bAVM by Onyx embolization were included (14 girls, 48%; median age 11.1 years, interquartile range, IQR 8.1-12.7 years) with a total of 72 endovascular sessions (median of 2 sessions per patient IQR 1-3). The AVMs were deeply located in 23 patients (79%). No systemic complications occurred, and no child experienced embolization-related persistent neurological deficits. Non-clinically relevant complications were observed during five procedures, unrelated to Onyx. After a mean follow-up of 31 months from rupture complete obliteration rates were 100%, 89%, 29%, 14% in bAVM Spetzler Martin grades I, II, III and IV-V, respectively.

CONCLUSION

It was found that Onyx embolization is safe and represents a good option for an initial treatment approach, in a sequential treatment strategy for pediatric ruptured brain AVMs. Younger age may not be an argument to deny Onyx embolization.

What is the best therapeutic approach to a pediatric patient with a deep-seated brain AVM?

Although brain arteriovenous malformations (bAVMs) account for a very small proportion of cerebral pathologies in the pediatric population, they are the cause of roughly 50% of spontaneous intracranial hemorrhages. Pediatric bAVMs tend to rupture more frequently and seem to have higher recurrence rates than bAVMs in adults. Thus, the management of pediatric bAVMs is particularly challenging. In general, the treatment options are conservative treatment, microsurgery, endovascular therapy (EVT), gamma knife radiosurgery (GKRS), proton-beam stereotactic radiosurgery (PSRS), or a combination of the above. In order to identify the best approach to deep-seated pediatric bAVMs, we performed a systematic review, according to the PRISMA guidelines. None of the options seem to offer a clear advantage over the others when used alone. Microsurgery provides the highest obliteration rate, but has higher incidence of neurological complications. EVT may play a role when used as adjuvant therapy, but as a stand-alone therapy, the efficacy is low and the long-term side effects of radiation from the multiple sessions required in deep-seated pediatric bAVMs are still unknown. GKRS has a low risk of complication, but the obliteration rates still leave much to be desired. Finally, PSRS offers promising results with a more accurate radiation that avoids the surrounding tissue, but data is limited due to its recent introduction. Overall, a multi-modal approach, or even an active surveillance, might be the most suitable when facing deep-seated bAVM, considering the difficulty of their management and the high risk of complications in the pediatric population.

Safety and outcome of combined endovascular and surgical management of low grade cerebral arteriovenous malformations in children compared to surgery alone

PURPOSE

To evaluate the outcomes of combined preoperative embolization and microsurgical resection in comparison with microsurgical resection alone as the current standard of care for low-grade cerebral arteriovenous malformations (AVM) in the pediatric population.

MATERIALS & METHODS

We performed a single-center retrospective study of pediatric patients presenting with Spetzler-Martin (SM) grade I and II cerebral AVMs at a high-volume tertiary pediatric hospital between January 2005 and September 2016. Low grade AVM patients were divided into two groups: pre-operative embolization with subsequent microsurgical resection or microsurgical resection alone. Patient demographics, clinical and imaging presentations, AVM morphological characteristics, post-operative complications, and mid to long-term clinical outcomes were studied. Post-embolization and post-surgical outcomes were assessed prior to and after treatment, at 3 months and at final follow-up using the modified Rankin Scale (mRS) to compare both final independent (mRS 0-2) and favorable (no change or improved mRS) clinical outcomes for comparison between study groups. Statistical associations of patient demographics, AVM characteristics/SM grading, and treatment modality group with post-operative complications were performed using univariate logistic regression analysis.

RESULTS

Thirty-four patients with low grade cerebral AVMs met the study inclusion criteria (mean age 10.6 ± 3.4 years; range 3-16 years, 22M:12 F). Twenty patients (59%) presented with ruptured AVMs. Twenty-five patients (73.5%) underwent combined treatment with embolization and microsurgical resection, while 9/34 (26.5%) underwent microsurgical resection alone. A total of 35 embolization procedures performed in 25 patients (Mode, 1; Range, 1-7) were associated with two minor post-embolization and 7 subsequent post-surgical (28%) complications, resulting in clinical deterioration in a single patient. Microsurgical resection alone was associated with 3 post-surgical complications (33%), resulting in permanent neurological disability in a single patient. There was no significance association of post-operative complications with either treatment modality group, combined treatment versus surgical resection alone [OR:1.13; 95% CI:0.23-5.62; p-value 0.88]. SM Grade II and eloquent locations were found to be significantly associated with post-surgical complications of low grade pediatric cerebral AVMs [OR 13.2 and OR 8 respectively, p-value 0.004 and 0.005). On mean follow-up time of 35.7 months, final clinical outcome was favorable in the majority of both treatment arms with no dependent (mRS>2) patients in the combined endovascular and surgical cohort. Two patients in the surgical cohort failed to achieve independent functional status, primarily due to a pre-operative morbid status (p-value 0.015). However, there was no significant difference in favorable outcomes between the treatment groups [p-value 0.14].

CONCLUSION

Our study suggests equivalent safety and favorable clinical outcomes related to combined endovascular embolization and microsurgical resection of low grade pediatric cerebral AVMs in comparison to microsurgical resection alone. On long term clinical follow-up, the vast majority of patients achieved an independent and favorable functional status irrespective of pre-operative embolization.

Coil and Onyx embolization of a torcular herophili dural arteriovenous fistula in a full-term neonate with advanced heart failure using a transumbilical approach

Neonatal dural arteriovenous fistulas (DAVFs) are rare, but if left untreated will advance to life-threatening neurological and cardiovascular compromise. Endovascular treatment is the preferred treatment modality for DAVFs. The goal of endovascular therapy is to obliterate feeding vasculature and prevent secondary complications. Endovascular access can be difficult to obtain in a neonate. The authors present the case of a full-term, normal birth weight neonate with severe congestive heart failure secondary to a congenital DAVF of the torcular herophili that was successfully treated with transumbilical arterial coil embolization and a liquid embolic agent.

Adjuvant Coil Assisted Glue Embolization of Vein of Galen Aneurysmal Malformation in Pediatric Patients

Purpose

Adjuvant coils may offer advantages in flow control during glue embolization of high flow vein of Galen aneurysmal malformation (VGAM) patients but involves specific issues such as feasibility, durability and coil mass effect. The purpose of this study is to assess the outcome of adjuvant coils in addition to transarterial glue embolization for treatment of these patients.

Materials and Methods

Five pediatric VGAM patients (age range; 11 weeks to 2 yrs 2 mos) with high flow fistulous angioarchitecture were treated with adjuvant coils 1) in the distal feeding artery and/or 2) in the vein of Galen followed by glue embolization of the shunt. The angiographic / clinical outcomes were assessed.

Results

Adjuvant coils were deployed in the distal feeding artery (n=3), vein of Galen pouch plus distal feeding artery (n=2). Additional transarterial glue embolization of the fistulae was successfully performed (n=4). Complete occlusion was achieved with coils in one case. Complete occlusion was achieved for all mural type cases (n=4). Residual feeders remained in a case of choroidal type of VGAM. No complications were noted related to the treatment. All patients showed normal development on follow up (range: 7.6 to 88.8 mo, mean 49.3 mo). Initial hydrocephalus improved on follow up despite coil mass effect in dilated vein of Galen.

Conclusion

Adjuvant coils for flow control with glue embolization may be a safe and effective treatment method for VGAM patients with high flow fistulous feeders.

Multimodality Management of Vein of Galen Malformations-An Institutional Experience

BACKGROUND

The vein of Galen aneurysmal malformation (VGM) is a rare intracranial arteriovenous fistula with a dramatic manifestation during infancy and 100% mortality without treatment. Therapeutic strategies for VGMs have changed over time as a result of advances in endovascular techniques. We present our experience and multimodality approach within the last 4 decades.

METHODS

A retrospective analysis and angiographic review were performed of patients with VGM between 1975 and 2016 at our institution.

RESULTS

Eighteen consecutive patients were identified, including 10 with choroidal and 8 with mural VGMs. In 37 endovascular interventions, a transarterial approach was mostly performed (82.8%). One patient was initially treated surgically and received 2 Gamma Knife treatments after multiple embolizations. The preferred embolization agent was histoacryl for choroidal VGMs and a combination of coils and histoacryl for mural VGMs. Total occlusion was achieved in 87.5% of mural VGMs and 11.1% of choroidal VGMs. Cerebral hemorrhages and infarction occurred only in patients younger than 1 month. At a median follow-up interval of 4.6 years, good outcome was achieved in 53.8% and poor outcome in 46.2%, with an overall mortality of 16.7%. Poor outcome was significantly associated with choroidal-type VGMs, age <1 month at first embolization, and incomplete occlusion.

CONCLUSIONS

Endovascular embolization using a transarterial approach is the therapy of choice. Gamma Knife radiosurgery can be considered as second-line therapy in a multimodal approach. Whereas treatment within the first month of life is associated with the highest mortality and complications, we did not detect any severe adverse events thereafter.

Biomaterials and Advanced Technologies for Hemostatic Management of Bleeding

Bleeding complications arising from trauma, surgery, and as congenital, disease-associated, or drug-induced blood disorders can cause significant morbidities and mortalities in civilian and military populations. Therefore, stoppage of bleeding (hemostasis) is of paramount clinical significance in prophylactic, surgical, and emergency scenarios. For externally accessible injuries, a variety of natural and synthetic biomaterials have undergone robust research, leading to hemostatic technologies including glues, bandages, tamponades, tourniquets, dressings, and procoagulant powders. In contrast, treatment of internal noncompressible hemorrhage still heavily depends on transfusion of whole blood or blood's hemostatic components (platelets, fibrinogen, and coagulation factors). Transfusion of platelets poses significant challenges of limited availability, high cost, contamination risks, short shelf-life, low portability, performance variability, and immunological side effects, while use of fibrinogen or coagulation factors provides only partial mechanisms for hemostasis. With such considerations, significant interdisciplinary research endeavors have been focused on developing materials and technologies that can be manufactured conveniently, sterilized to minimize contamination and enhance shelf-life, and administered intravenously to mimic, leverage, and amplify physiological hemostatic mechanisms. Here, a comprehensive review regarding the various topical, intracavitary, and intravenous hemostatic technologies in terms of materials, mechanisms, and state-of-art is provided, and challenges and opportunities to help advancement of the field are discussed.

Endovascular Treatment of Vein of Galen Malformations: A Systematic Review and Meta-Analysis

BACKGROUND

Outcomes after endovascular embolization of vein of Galen malformations remain relatively poorly described.

PURPOSE

We performed a systematic review of the literature to determine outcomes and predictors of good outcomes following endovascular treatment of vein of Galen malformations.

DATA SOURCES

We used Ovid MEDLINE, Ovid Embase, and the Web of Science.

STUDY SELECTION

Our study consisted of all case series with ≥4 patients receiving endovascular treatment of vein of Galen malformations published through January 2017.

DATA ANALYSIS

We studied the following outcomes: complete/near-complete occlusion rates, technical complications, perioperative stroke, perioperative hemorrhage, technical mortality, all-cause mortality, poor neurologic outcomes, and good neurologic outcomes. Outcomes were stratified by age-group (neonate, infant, child). A random-effects meta-analysis was performed.

DATA SYNTHESIS

A total of 27 series with 578 patients were included; 41.9% of patients were neonates, 45.0% of patients were infants, and 13.1% of patients were children. All-cause mortality was 14.0% (95% CI, 8.0%-22.0%). Overall good neurologic outcome rates were 62.0% (95% CI, 57.0%-67.0%). Overall poor neurologic outcome rates were 21.0% (95% CI, 17.0%-26.0%). Neonates were significantly less likely to have good neurologic outcomes than infants (48.0%; 95% CI, 35.0%-62.0% versus 77.0%; 95% CI, 70.0%-84.0%; P < .01). Treatment indications following the Bicêtre neonatal evaluation score resulted in significantly higher rates of good neurologic outcome (P = .04). Patients with congestive heart failure had significantly lower rates of good neurologic outcome (OR, 0.50; 95% CI, 0.28-0.88; P = .01).

LIMITATIONS

Limitations were selection and publication biases.

CONCLUSIONS

Patients receiving endovascular embolization of vein of Galen malformations experienced good long-term clinical outcomes in >60% of cases. Appropriate patient selection is key as treatment guided by the Bicêtre neonatal evaluation score was associated with improved neurologic outcomes.

A Case Report of Onyx Pulmonary Arterial Embolism Contributing to Hypoxemia During Awake Craniotomy for Arteriovenous Malformation Resection

A healthy 26-year-old man with cerebral arteriovenous malformation underwent staged endovascular embolization with Onyx followed by awake craniotomy for resection. The perioperative course was complicated by tachycardia and severe intraoperative hypoxemia requiring significant oxygen supplementation. Postoperative chest computed tomography (CT) revealed hyperattenuating Onyx embolization material within the pulmonary vasculature, and an electrocardiogram indicated possible right heart strain, supporting clinically significant embolism. With awake arteriovenous malformation resection following adjunctive Onyx embolization becoming increasingly employed for lesions involving the eloquent cortex, anesthesiologists need to be aware of pulmonary migration of Onyx material as a potential contributor to significant perioperative hypoxemia.

Pediatric intracranial dural arteriovenous fistulas: age-related differences in clinical features, angioarchitecture, and treatment outcomes

OBJECTIVE Intracranial dural arteriovenous fistulas (DAVFs) are rare in children. This study sought to better characterize DAVF presentation, angioarchitecture, and treatment outcomes. METHODS Children with intracranial DAVFs between 1986 and 2013 were retrospectively identified from the neurointerventional database at the authors' institution. Demographics, clinical presentation, lesion angioarchitecture, treatment approaches, angiographic outcomes, and clinical outcomes were assessed. RESULTS DAVFs constituted 5.7% (22/423) of pediatric intracranial arteriovenous shunting lesions. Twelve boys and 10 girls presented between 1 day and 18 years of age; boys presented at a median of 1.3 years and girls presented at a median of 4.9 years. Four of 8 patients ≤ 1 year of age presented with congestive heart failure compared with 0/14 patients > 1 year of age (p = 0.01). Five of 8 patients ≤ 1 year old presented with respiratory distress compared with 0/14 patients > 1 year old (p = 0.0021). Ten of 14 patients > 1 year old presented with focal neurological deficits compared with 0/8 patients ≤ 1 year old (p = 0.0017). At initial angiography, 16 patients harbored a single intracranial DAVF and 6 patients had 2-6 DAVFs. Eight patients (38%) experienced DAVF obliteration by the end of treatment. Good clinical outcome (modified Rankin Scale score 0-2) was documented in 77% of patients > 1 year old at presentation compared with 57% of patients ≤ 1 year old at presentation. Six patients (27%) died. CONCLUSIONS Young children with DAVFs presented predominantly with cardiopulmonary symptoms, while older children presented with focal neurological deficits. Compared with other pediatric vascular shunts, DAVFs had lower rates of angiographic obliteration and poorer clinical outcomes.

Retreatment of a choroidal vein of Galen malformation with embolization 42 years after open surgical treatment in the neonatal period

In 1976 an infant boy initially presented with a choroidal vein of Galen malformation (cVOGM). Craniotomy and clipping of the anterior cerebral artery and posterior choroidal arteries was performed, which was reported in the literature 40 years ago. The patient remained asymptomatic until age 42 when he re-presented with an isolated intraventricular hemorrhage. Angiography demonstrated cVOGM with venous sinus occlusive disease leading to venous hypertension and subsequent intraventricular hemorrhage. The angiogram also demonstrated a 'pseudo-nidus' composed of multiple arterial-to-arterial anastomoses that had developed as a result of the original surgical treatment. We embolized a portion of the lesion to reduce the venous hypertension. The patient has been asymptomatic for more than 2 years. To our knowledge, this is the first reported case of a symptomatic neonatal VOGM treated with open surgery that required embolization as an adult for a delayed hemorrhagic presentation.

Therapeutic progress in pediatric intracranial dural arteriovenous shunts: A review

Pediatric dural arteriovenous shunts (dAVSs) are a rare form of vascular disease: Fewer than 100 cases are reported in PubMed and the understanding of pediatric dAVS is limited. For this study, we searched in PubMed, reviewed and summarized the literature related to pediatric dAVSs. Our review revealed that pediatric dAVSs have an unfavorable natural history: If left untreated, the majority of pediatric dAVSs deteriorate. In a widely accepted classification scheme developed by Lasjaunias et al., pediatric dAVSs are divided into three types: Dural sinus malformation (DMS) with dAVS, infantile dAVS (IDAVS) and adult-type dAVS (ADAVS). In general, the clinical manifestations of dAVS can be summarized as having symptoms due to high-flow arteriovenous shunts, symptoms from retrograde venous drainage, symptoms from cavernous sinus involvement and hydrocephalus, among other signs and symptoms. The pediatric dAVSs may be identified with several imaging techniques; however, the gold standard is digital subtraction angiography (DSA), which indicates unique anatomical details and hemodynamic features. Effectively treating pediatric dAVS is difficult and the prognosis is often unsatisfactory. Transarterial embolization with liquid embolic agents and coils is the treatment of choice for the safe stabilization and/or improvement of the symptoms of pediatric dAVS. In some cases, transumbilical arterial and transvenous approaches have been effective, and surgical resection is also an effective alternative in some cases. Nevertheless, pediatric dAVS can have an unsatisfactory prognosis, even when timely and appropriate treatment is administered; however, with the development of embolization materials and techniques, the potential for improved treatments and prognoses is increasing.

Relapsing fetal bilateral hydrothorax, an isolated expression of a vein of Galen aneurysmal malformation

We report a case of bilateral fetal hydrothorax presenting at 20 weeks of pregnancy, spontaneously resolving at 22 weeks and severely relapsing at 28 weeks in a fetus with normal karyotype. The cause was a high-output heart failure caused by vein of Galen malformation.

Flow control using Scepter™ balloons for Onyx embolization of a vein of Galen aneurysmal malformation

PURPOSE

We present a technical development of the endovascular treatment technique for vein of Galen aneurysmal malformation, using Onyx™ (ethylene vinyl alcohol copolymer) delivered under flow control through double-lumen balloon microcatheters.

MATERIALS AND METHODS

An 11-month-old patient that initially presented with increasing head circumference was diagnosed with mural type vein of Galen aneurysmal malformation. Complete cure was obtained in a single endovascular treatment session. Onyx was delivered simultaneously through two double-lumen balloon microcatheters (Scepter™, Microvention, Terumo Group). In both arterial feeders, balloon inflation occluded the high-flow arterial-venous shunting and thus facilitated the controlled propagation of the embolic product in the afferent artery and the shunt point while preventing distal migration into the venous system.

RESULTS

Two years post-procedure, MR imaging showed persistent occlusion of arterial-venous shunts with complete regression of the venous dilatation. On clinical examination, the patient had no neurological deficits, and no cognitive impairment was detected at neuropsychological testing.

CONCLUSION

The use of double-lumen balloon microcatheters for flow control during delivery of Onyx represents a viable alternative for the endovascular treatment of vein of Galen aneurysmal malformations.

Anesthesia for interventional radiology

Pediatric patients in the neurointerventional radiology setting pose the dual challenges of caring for relatively sick patients in the outfield environment. For safe and successful practice, the anesthesiologist must not only understand the nuances of pediatric anesthesia and the physiologic demands of the cerebral lesions. They must also help maintain a team-based approach to safe, compassionate care of the child in this challenging setting. In this review article, we summarize key aspects of success for several of these topics.

Long-term outcome of 106 consecutive pediatric ruptured brain arteriovenous malformations after combined treatment

BACKGROUND AND PURPOSE

Childhood intracerebral hemorrhage is mainly attributable to underlying brain arteriovenous malformations (bAVMs). Multimodal treatment options for bAVMs include microsurgery and embolization, allowing an immediate cure, and radiosurgery, entailing longer obliteration times. Follow-up data on pediatric ruptured bAVMs are scarce, making it difficult to assess the risk of subsequent intracerebral hemorrhage. Our aim was to assess the clinical and angiographic outcome and to analyze risk factors for rebleeding during and after combined treatment of pediatric bAVMs.

METHODS

A prospectively maintained database of children referred to our institution between January 1997 and October 2012 for bAVMs was retrospectively queried to identify all consecutive ruptured bAVMs treated by surgery, embolization, and radiosurgery. The impact of baseline clinical and bAVM characteristics on clinical outcome, rebleeding rate, annual bleeding rate, and bAVM obliteration was studied using univariate and multivariate Cox regression analysis.

RESULTS

One hundred six children with ruptured bAVMs were followed up for a total of 480.5 patient-years (mean, 4.5 years). Thirteen rebleeding events occurred, corresponding to an annual bleeding rate of 2.71±1.32%, significantly higher in the first year (3.88±1.39%) than thereafter (2.22±1.38%; P<0.001) and in the case of associated aneurysms (relative risk, 2.68; P=0.004) or any deep venous drainage (relative risk, 2.97; P=0.002), in univariate and multivariate analysis. Partial embolization was associated with a higher annual bleeding rate, whereas initial surgery for intracerebral hemorrhage evacuation was associated with a lower risk of rebleeding.

CONCLUSIONS

Associated aneurysms and any deep venous drainage are independent risk factors for rebleeding in pediatric ruptured bAVMs. Immediate surgery or total embolization might be advantageous for children harboring such characteristics, whereas radiosurgery might be targeted at patients without such characteristics.

Challenges in pediatric neuroanesthesia: awake craniotomy, intraoperative magnetic resonance imaging, and interventional neuroradiology

This article gives a review of 3 challenges in caring for children undergoing neurosurgical and neurointerventional procedures. Anesthesiologists may have experience with certain aspects of these situations but may not have extensive experience with each clinical setting. This review addresses issues with awake craniotomy, intraoperative magnetic resonance imaging, and neurointerventional procedures in children with neurologic disease. Familiarization with these complex clinical scenarios and their unique considerations allows the anesthesiologist to deliver optimal care and helps facilitate the best possible outcome for these patients.

Vascular anomalies: hemangiomas and beyond--part 1, Fast-flow lesions

OBJECTIVE

The purpose of this study was to review the medical literature and the current classification of vascular anomalies to clarify common misconceptions and provide guidance for imaging and treatment. In this first article of a two-part series, we focus on the fast-flow vascular anomalies.

CONCLUSION

Nonuniformity of terminology across the medical literature hampers understanding of the vascular anomalies. A familiarity with the classification and biology on which this terminology is based is essential for accurate and precise diagnosis.

Onyx embolization of intracranial arteriovenous malformations in pediatric patients

OBJECT

The authors undertook this study to assess the safety and efficacy of Onyx embolization in the treatment of intracranial arteriovenous malformations (AVMs) in pediatric patients.

METHODS

All pediatric Onyx embolization of intracranial AVM cases performed consecutively at a single children's hospital over a 5-year period were collected and evaluated.

RESULTS

Twenty-five patients (mean age 10.5 years) underwent a total of 38 procedures. An aggregate of 56 pedicles were embolized (mean 1.47 per session). The Spetzler-Martin grade was determined in all cases. Onyx embolization resulted in complete obliteration of the AVM in 3 cases (12%) and partial obliteration in 22 cases (88%). A total of 23 patients underwent surgical treatment. The mean preoperative AVM devascularization in these cases was 72%. One patient was treated with radiosurgery following Onyx embolization. Overall, 10 complications occurred in a total of 38 procedures (26.3%). None of the complications resulted in permanent neurological morbidity. The rate of transient neurological complications was 10.5% (4 of 38 procedures) and the rate of transient nonneurological complications was 5.3% (2 of 38 procedures). The remaining 4 complications were clinically silent (rate of 10.5%). There were no procedure-related deaths in this study population. There was no significant difference in patients with and without complications in terms of demographic characteristics, AVM grade, or embolization features (p ≥ 0.2). Deep venous drainage was associated with higher complication rates (p = 0.03).

CONCLUSIONS

Onyx utilization is feasible for preoperative or primary embolization in the treatment of pediatric intracranial AVMs; however, the spectrum of complications encountered is broad, and attention must be paid to the technical nuances of and indications for its use to avoid many potential dangerous effects. Although the overall complication rates were higher than expected, all were either clinically silent or had only transient clinical effects. Thus, this experience suggests that Onyx embolization can be performed safely with a low rate of permanent morbidity in pediatric patients harboring these difficult lesions.

Safety and Efficacy of Onyx Embolization for Pediatric Cranial and Spinal Vascular Lesions and Tumors

BACKGROUND:

Although Onyx is widely used to embolize vascular lesions in adults, the safety and efficacy of this liquid embolic agent for use in children are not well studied.

OBJECTIVE:

To report our experience using Onyx in pediatric patients for a variety of cranial and spinal vascular lesions and tumors to determine its procedural complication rates, types, and clinical consequences and to highlight the indications for and principles of Onyx embolization in pediatric patients.

METHODS:

All pediatric Onyx embolization cases performed consecutively by the neuroendovascular services at our 2 institutions over a 5-year period were collected retrospectively and analyzed.

RESULTS:

Over the study period, 105 Onyx embolization procedures were performed in 69 pediatric patients with a mean follow-up of 112 days. Fifty-two patients harbored “primary” vascular lesions (malformations, fistulas, etc), whereas 17 patients had tumors. Complications occurred in 25 of 105 procedures (23.8%) and included ischemic infarct (7), asymptomatic nontarget embolization (4), intracerebral hemorrhage (3), microcatheter-related vessel perforation (3), retained microcatheter (2), cerebral edema (2), dimethyl sulfoxide-induced pulmonary edema (2), facial ischemia (1), and contrast-induced bronchospasm (1). Neurological morbidity occurred transiently after 10 procedures (9.5%) and permanently after 2 procedures (1.9%). There were no procedure-related deaths. Statistical analysis revealed no predictors of complications among the multiple potential risk factors evaluated.

CONCLUSION:

Our experience suggests that Onyx can be used effectively for embolization of pediatric cranial and spinal vascular lesions and tumors with low permanent morbidity; however, attention must be paid to the technical nuances of and indications for its use to avoid potential complications.

Spinal arteriovenous fistulas in children with hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant angiodysplasia with high penetrance and variable expression. The manifestations of HHT are often age related, and spinal arteriovenous fistula (AVF) may be the initial presentation of HHT in young children. Because spinal AVFs are rarely reported, however, screening is not incorporated into current clinical recommendations for the treatment of patients with HHT. The authors describe 2 cases of children younger than 2 years of age with acute neurological deterioration in the context of a spinal AVF and in whom HHT was subsequently diagnosed. One patient presented with intraventricular and subarachnoid hemorrhage and the other with acute thrombosis of an intramedullary varix. These cases highlight the potential for significant neurological morbidity from a symptomatic AVF in very young children with HHT. Given the lack of data regarding the true incidence and natural history of these lesions, these cases raise the question of whether spinal cord imaging should be incorporated into screening recommendations for patients with HHT.

The use of Onyx for embolization of peripheral vascular malformations in pediatric patients

PURPOSE

The management of congenital peripheral vascular malformations (VMs) can present a difficult therapeutic challenge. Endovascular transcatheter embolization of peripheral VMs is widely accepted as a first therapeutic option for many VMs. However, data describing the use of Onyx are limited in children with peripheral VMs. Our aim is to retrospectively evaluate the results of transcatheter arterial embolization with Onyx for peripheral VMs in children.

MATERIALS AND METHODS

We analyzed clinical and imaging records of 16 patients who underwent 25 embolization procedures by using Onyx for peripheral VMs. In eight cases, embolization procedures were performed once; in seven cases, twice; and in one case, thrice.

RESULTS

Embolization was technically complete in 4 patients and incomplete in 12 patients. Clinically, complete success was achieved in nine patients, and partial success was achieved in six patients. In one patient, reflux to the anterior and posterior tibial arteries caused peripheral ischemia, and the patient was referred to undergo plastic surgery. There were no complications in the other 15 patients.

CONCLUSION

With future studies to better characterize the safety profile of this agent in peripheral vasculature, embolization with Onyx may become a valuable treatment option for peripheral VMs in pediatric patients.

Endovascular embolization for symptomatic perimedullary AVF and intramedullary AVM: a series and a literature review

INTRODUCTION

Perimedullary arteriovenous fistula (AVF) has shunt on the spinal cord surface and it can be treated with surgery, or endovascular embolization. Intramedullary arteriovenous malformation (AVM) has its nidus in the cord and is difficult to treat either by surgery or endovascular technique. We report our experience with endovascular embolization in the treatment of perimedullary AVF and intramedullary AVM.

METHODS

Four consecutive cases of spinal perimedullary AVF and six intramedullary AVM were retrospectively reviewed. These cases were evaluated and treated at Beijing Tiantan Hospital, China, over a 2-year period. A review of previously reported cases was also performed.

RESULTS

There was no significant difference in the presentations (P = 0.348), level of lesions (P = 0.350), arterial suppliers (P = 0.801), and associated vascular anomalies between perimedullary AVF and intramedullary AVM, except for age (P = 0.014) and treatment modalities (P = 0.003). The patients with perimedullary AVFs were younger in our cases; the age at onset of symptoms averaged 25.8 years compared to 31.7 years for intramedullary AVMs. There was a significant male predominance for both lesions, and a significantly higher incidence of subarachnoid hemorrhage than in spinal dural AVFs. Regarding treatment, endovascular coil embolization is frequently used in perimedullary AVF and liquid embolic agent is an effective therapeutic choice in intramedullary AVM.

CONCLUSION

Perimedullary AVF and intramedullary AVM are dissimilar with dural AVF in clinical characteristics. Our experience suggests that the endovascular treatment of spine perimedullary AVFs and intramedullary AVMs is feasible and effective. Endovascular treatment for intramedullary AVMs is still challenging, the main problem is acute ischemia injury of the spinal cord.

Intracranial Aneurysms and Vascular Malformations: Diagnosis for Therapy

In the second part of our overviewstudy the diagnosis for the treatment of our patients with intracranial vascular malformations (aneurysms / AVMF– arteriovenous malformations) is again shown in a region of about 500.000 inhabitants and just an overview of the outcome. This second part will be an overall comparison between the former diagnostic for the treatment and the here described diagnostic for the treatment (CTA, MRA, DSA rot / microsurgery, endovascular interventional techniques etc.), concerning also the topography and the demography. The future trends are also outlined.

Stretched and sheared microcatheter retained after onyx embolization of infantile myofibromatosis

We describe a rare neurointerventional complication, namely a stretched and sheared microcatheter, extending 52 cm from its point of retention within an Onyx cast in an infant patient's neck mass, to the groin. The tumor was an unusual manifestation of infantile myofibromatosis and prior attempts at resection had proven impossible due to bleeding. Recommendations regarding microcatheter selection, diagnostic workup, and management of the ensuing complication are given.

Vein of Galen aneurysmal malformation: combined transvenous and transarterial method using a "kissing microcatheter technique"

INTRODUCTION

Vein of Galen aneurysmal malformation (VGAM) is a severe pediatric neurovascular disease. Children often present with congestive heart failure in the neonatal period. In the last decades, endovascular treatment became the first therapeutic option. The purpose of this study is to report our results in the treatment of VGAM with a combined transvenous and transarterial method in the last ten years.

METHODS

In our cohort of 28 patients with VGAM, 22 patients were treated endovascularly between 1992 and 2010. In the last 10 years, a consecutive series of 14 children were treated with a combined transvenous and transarterial method. The therapeutic goal was immediate shunt reduction of the arteriovenous malformation, especially in the neonatal period. Closure of the fistulous connections was achieved by coiling using a combined transvenous and transarterial approach, called "kissing microcatheter technique".

RESULTS

Eight of 14 children presented in the neonatal period with severe congestive heart failure. The other six patients presented between the age of 2 and 17 months. One patient died due to a non-procedural complication in another hospital 2 years after the last treatment. Complete or >90% of angiographically confirmed closure of the malformation was documented in 11 of 14 patients. Normal or near-normal outcome was achieved in 9 of 13 surviving children, a non-favorable outcome was observed in four children. Control of heart failure was achieved in all patients.

CONCLUSION

Endovascular treatment of VGAM using a combined transvenous and transarterial method is a safe procedure with a low complication rate. The overall outcome can be improved, especially in the high-risk neonatal group with congestive heart failure.

Vein of Galen aneurysmal malformation: combined transvenous and transarterial method using a "kissing microcatheter technique"

INTRODUCTION

Vein of Galen aneurysmal malformation (VGAM) is a severe pediatric neurovascular disease. Children often present with congestive heart failure in the neonatal period. In the last decades, endovascular treatment became the first therapeutic option. The purpose of this study is to report our results in the treatment of VGAM with a combined transvenous and transarterial method in the last ten years.

METHODS

In our cohort of 28 patients with VGAM, 22 patients were treated endovascularly between 1992 and 2010. In the last 10 years, a consecutive series of 14 children were treated with a combined transvenous and transarterial method. The therapeutic goal was immediate shunt reduction of the arteriovenous malformation, especially in the neonatal period. Closure of the fistulous connections was achieved by coiling using a combined transvenous and transarterial approach, called "kissing microcatheter technique".

RESULTS

Eight of 14 children presented in the neonatal period with severe congestive heart failure. The other six patients presented between the age of 2 and 17 months. One patient died due to a non-procedural complication in another hospital 2 years after the last treatment. Complete or >90% of angiographically confirmed closure of the malformation was documented in 11 of 14 patients. Normal or near-normal outcome was achieved in 9 of 13 surviving children, a non-favorable outcome was observed in four children. Control of heart failure was achieved in all patients.

CONCLUSION

Endovascular treatment of VGAM using a combined transvenous and transarterial method is a safe procedure with a low complication rate. The overall outcome can be improved, especially in the high-risk neonatal group with congestive heart failure.

Safety and clinical efficacy of Onyx for embolization of extracranial head and neck vascular anomalies

BACKGROUND AND PURPOSE

Onyx was developed for embolization of central nervous system AVMs but is increasingly used extracranially because of its unique physical properties. We review our experience and results with the use of Onyx for the treatment of fast-flow extracranial vascular lesions.

MATERIALS AND METHODS

We retrospectively analyzed clinical and imaging records of 22 patients who underwent 71 extracranial embolizations from March 2007 through January 2010. The diagnoses were the following: cervicofacial AVM (n = 18), traumatic fistula (n = 3), and vessel laceration (n = 1). In 62 of 71 procedures (87%), Onyx was the sole embolic agent; it was delivered transarterially in 67/71 and percutaneously in 4/71 procedures. Clinical goals included amelioration of pain and control of bleeding. The clinical efficacy of embolization was judged by symptom control, and adverse events were assessed by clinical examination and history, both postembolization and 4 weeks postprocedure.

RESULTS

Cessation of acute bleeding was achieved in 13/14 cases, with 1 case of immediate recurrent massive epistaxis prompting reintubation and further embolization. Control of subacute bleeding episodes and pain was achieved for all patients. Following staged embolization, 7 patients underwent surgical resection without significant blood loss. Surgeons reported high satisfaction with the intraoperative handling properties of Onyx. Transient swelling, local tenderness, or numbness was encountered after 7 procedures. There were no stuck catheters, vessel dissections, or vessel ruptures and no skin discoloration.

CONCLUSIONS

Staged Onyx embolization was clinically efficacious in managing extracranial fast-flow vascular malformations and lesions, with low associated morbidity.