Treatment Of Intracranial Arteriovenous Malformations Research Articles

The impact of embolization on radiosurgery obliteration rates for brain arteriovenous malformations: a systematic review and meta-analysis.

There exists no consensus in the literature regarding the impact of pre-stereotactic radiosurgery (SRS) embolization on obliteration rates and clinical outcome after radiosurgery treatment of intracranial arteriovenous malformations (AVM). We performed a systematic review of four databases and included studies with at least 10 patients evaluating obliteration rates of intracranial AVMs treated with SRS alone (SRS cohort) and combined pre-SRS embolization followed by SRS (E + SRS cohort). Meta-analytic results were pooled together via random-effects models. A total of 43 studies, with 7103 patients, were included in our analysis. Among our included patients, complete obliteration was achieved in 51.5% (964/1871) of patients in the E + SRS cohort as compared to 61.5% (3217/5231) of patients in the SRS cohort. Meta-analysis of the pooled data revealed that obliteration was significantly lower in the E + SRS cohort (pooled OR = 0.64, 95% CI = 0.54-0.75, p < 0.0001). The use of pre-SRS embolization was significantly associated with lower AVM obliteration rates when compared to treatment with SRS alone. Our analysis seeks to provide a macroscopic insight into the complex interaction between pre-SRS embolization and brain AVM obliteration rates and prognosis. Pre-SRS embolization may still be beneficial in select patients, and further studies are needed to identify patients who benefit from neoadjuvant AVM embolization.

Complete seizure-free rates following interventional treatment of intracranial arteriovenous malformations: a systematic review and meta-analysis.

Seizures are common presenting symptoms of intracranial arteriovenous malformations (AVMs). This systematic review and meta-analysis aims to assess the current evidence regarding complete seizure freedom rates following surgical resection, stereotactic radiosurgery (SRS), and/or endovascular embolization of intracranial AVMs. A systematic review of PubMed, Ovid MEDLINE, and Ovid EMBASE was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Included manuscripts were methodically scrutinized for quality, spontaneous AVM-associated or hemorrhage-associated seizures, complete seizure-free rates following each interventional treatment, follow-up duration; determination methods of seizure outcomes, and average time-to-onset of recurrent seizures after each treatment. Manuscripts that described patients with nondisabling seizures or reduced seizure frequency in their seizure-free calculations were excluded. Seizure freedom rates following surgical resection, SRS, and endovascular embolization were compared via random-effect analysis. Thirty-four studies with a total of 1765 intracranial AVM patients presenting with spontaneous AVM-associated seizures and 408 patients presenting with hemorrhage-associated seizures were qualitatively analyzed. For patients presenting with AVM-associated seizures, the complete seizure-free rates were 73.0% (321/440 patients; 95% CI 68.8-77.1%) following surgical resection, 60.5% (376/622 patients; 95% CI 56.6-64.3%) following SRS, and 44.6% (29/65 patients; 95% CI 32.5-56.7%) following endovascular embolization alone. For patients presenting with either AVM-associated or hemorrhage-associated seizures, the complete seizure-free rates were 73.0% (584/800 patients; 95% CI 69.9-76.1%) following surgical resection, 46.4% (572/1233 patients; 95% CI 43.6-49.2%) following SRS, and 44.6% (29/65 patients; 95% CI 32.5-56.7%) following embolization. For patients presenting with either AVM-associated or hemorrhage-associated seizures, the overall improvements in seizure outcomes regardless of complete seizure freedom were 82.6% (661/800 patients; 95% CI 80.0-85.3%), 70.6% (870/1233 patients; 95% CI 68.0-73.1%), and 70.8% (46/65 patients; 95% CI 59.7-81.1%) following surgical resection, SRS, and embolization, respectively. No study reported information about the time-to-onset for recurrent seizures in any patient following treatment, as seizure outcomes were only described at the last follow-up visit. The available data suggests that surgical resection results in the highest rate of complete seizure freedom. The rate of seizure improvement following surgery increased further to 82.3% when including patients who had improved seizure frequency without achieving true seizure freedom. Complete seizure-free rates following SRS or embolization were more ambiguous and lower when compared to surgical resection. There is a need for high quality studies evaluating AVM treatment modalities and clearly defined seizure outcomes, as the current literature consists mostly of heterogenous patient populations.

Virtual embolization for treatment support of intracranial AVMs using an interactive desktop and VR application

PurposeThe treatment of intracranial arteriovenous malformations (AVM) is challenging due to their complex anatomy. For this vessel pathology, arteries are directly linked to veins without a capillary bed in between. For endovascular treatment, embolization is carried out, where the arteries that supply the AVM are consecutively blocked. A virtual embolization could support the medical expert in treatment planning.MethodWe designed and implemented an immersive VR application that allows the visualization of the simulated blood flow by displaying millions of particles. Furthermore, the user can interactively block or unblock arteries that supply the AVM and analyze the altered blood flow based on pre-computed simulations.ResultsIn a pilot study, the application was successfully adapted to three patient-specific cases. We performed a qualitative evaluation with two experienced neuroradiologist who regularly conduct AVM embolizations. The feature of virtually blocking or unblocking feeders was rated highly beneficial, and a desire for the inclusion of quantitative information was formulated.ConclusionThe presented application allows for virtual embolization and interactive blood flow visualization in an immersive virtual reality environment. It could serve as useful addition for treatment planning and education in clinical practice, supporting the understanding of AVM topology as well as understanding the influence of the AVM’s feeding arteries.

Magnetic resonance imaging detected radiation-induced changes in patients with proton radiation-treated arteriovenous malformations.

BackgroundTreatment of intracranial arteriovenous malformations (AVMs) includes surgery, radiation therapy, endovascular occlusion, or a combination. Proton radiation therapy enables very focused radiation, minimizing dose to the surrounding brain.PurposeTo evaluate the presence of radiation-induced changes on post-treatment MRI in patients with AVMs treated with proton radiation and to compare these with development of symptoms and nidus obliteration.Material and MethodsRetrospective review of pre- and post-treatment digital subtraction angiography and MRI and medical records in 30 patients with AVMs treated with proton radiation. Patients were treated with two or five fractions; total radiation dose was 20–35 physical Gy. Vasogenic edema (minimal, perinidal, or severe), contrast enhancement (minimal or annular), cavitation and nidus obliteration (total, partial, or none) were assessed.Results26 of 30 patients (87%) developed MRI changes. Vasogenic edema was seen in 25 of 30 (83%), abnormal contrast enhancement in 18 of 26 (69%) and cavitation in 5 of 30 (17%). Time from treatment to appearance of MRI changes varied between 5 and 25 months (median 7, mean 10). Seven patients developed new or deteriorating symptoms that required treatment with corticosteroids; all these patients had extensive MRI changes (severe vasogenic edema and annular contrast enhancement). Not all patients with extensive MRI changes developed symptoms. We found no relation between MRI changes and nidus obliteration.ConclusionRadiation-induced MRI changes are seen in a majority of patients after proton radiation treatment of AVMs. Extensive MRI changes are associated with new or deteriorating symptoms.

Arteriovenous Malformations Treated With Frameless Robotic Radiosurgery Using Non-Invasive Angiography: Long-Term Outcomes of a Single Center Pilot Study

ObjectiveCT-guided, frameless robotic radiosurgery is a novel radiotherapy technique for the treatment of intracranial arteriovenous malformations (AVMs) that serves as an alternative to traditional catheter-angiography targeted, frame-based methods.MethodsPatients diagnosed with AVMs who completed single fraction frameless robotic radiosurgery at Medstar Georgetown University Hospital between July 20, 2006 – March 11, 2013 were included in the present study. All patients received pre-treatment planning with CT angiogram (CTA) and MRI, and were treated using the CyberKnife radiosurgery platform. Patients were followed for at least four years or until radiographic obliteration of the AVM was observed.ResultsTwenty patients were included in the present study. The majority of patients were diagnosed with Spetzler Martin Grade II (35%) or III (35%) AVMs. The AVM median nidus diameter and nidal volume was 1.8 cm and 4.38 cc, respectively. Median stereotactic radiosurgery dose was 1,800 cGy. After a median follow-up of 42 months, the majority of patients (81.3%) had complete obliteration of their AVM. All patients who were treated to a total dose of 1800 cGy demonstrated complete obliteration. One patient treated at a dose of 2,200 cGy developed temporary treatment-related toxicity, and one patient developed post-treatment hemorrhage.ConclusionsFrameless robotic radiosurgery with non-invasive CTA and MRI radiography appears to be a safe and effective radiation modality and serves as a novel alternative to traditional invasive catheter-angiography, frame-based methods for the treatment of intracranial AVMs. Adequate obliteration can be achieved utilizing 1,800 cGy in a single fraction, and minimizes treatment-related side effects.

Multimodality treatment of intracranial arteriovenous malformations in South Island, New Zealand

Treatment of intracranial arteriovenous malformations is complex and multidisciplinary. This article presents the treatment model utilized in Christchurch, New Zealand which provides cerebrovascular surgery and interventional neuroradiology to the entire south island (approximate population of 1.1 million). A total of 40 patients treated over a 10 year period (2004–2014) are analysed here. Nine patients were managed surgically and complete resection was achieved in 100% of cases. Permanent mortality was 0% and permanent morbidity was 22% however median mRS improved from 3.0 preoperatively to 1.0 at follow up. Embolisation was utilized in 31 patients (mean age 40), of which 45% presented with haemorrhage, 39% with seizures, 10% with a headache only, and 6% with a deficit. None were found incidentally. The Spetzler-Martin grade 1 cases accounted for 10% of the cohort, 23% were grade II, 42% grade III, 23% grade IV and 3% grade V. A single aneurysm was present in 42% of cases, and multiple in 13%. The nidus was obliterated in 9.6% of cases with a morbidity rate of 6.5% and mortality rate of 3%. Modified Rankin scale improved marginally from 0.9 at diagnosis to 0.88 at final follow up (mean 22 months). There were no cases of recanalization. The total nidus obliteration rate using our algorithm of surgery alone for small accessible lesions, then staged embolization for larger lesions with adjuvant radiosurgery reserved for cases with residual nidus, was 50%.

Functional and educational outcomes after treatment for intracranial arteriovenous malformations in children

BackgroundArteriovenous malformations (AVMs) in the pediatric population are rare, yet they form the most frequent cause of hemorrhagic stroke in children. Compared to adults, children have been suggested to have beneficial neurological outcomes. However, few studies have focused on other variables than neurological outcomes. This study aims to assess the long-term functional and educational outcomes of children after multimodality approach of treatment for intracranial AVMs.MethodsAll children treated in our center between 1998 and 2016 for intracranial AVMs were reviewed. Patient characteristics, as well as AVM specifics, were collected. Functional outcomes were compared using the modified Rankin scale (mRs). Educational levels, using the International Standard Classification of Education (ISCED), were compared to the age-matched general population of the Netherlands.ResultsIn total, 25 children were included at mean age of 10 years (range 2–16 years). Nineteen patients (76%) presented with intracranial bleeding. Mean follow-up was 11.5 ± 5.3 years (range 4.1–24.4). Four (16%) of patients were treated with embolization, three (12%) with microsurgery, and 18 patients (72%) received a combination of different treatment modalities. Altogether, 21 (84%) were embolized, 14 (56%) were treated with microsurgery, and eight (32%) received stereotactic radiosurgery. One child had a worse mRs at discharge compared to admission; all others improved (n = 11) or were stable (n = 13). At follow-up, all patients scored a stable or improved mRs compared to discharge, with 23 children (92%) scoring mRs 0 or 1. These 23 children followed regular education during follow-up without specialized or adapted schooling. No significant differences in educational level with the age-matched general population were found.ConclusionThis retrospective review shows positive long-term results of both functional and educational outcomes after multidisciplinary treatment of pediatric brain AVMs.

Transvenous embolization for intracranial arteriovenous malformations: study protocol for a prospective, single-center cohort trial

Background and objectives: In 2010, Nguyen et al. reported a novel method for the treatment of intracranial arteriovenous malformations by transvenous embolization combined with conventional treatment. At present, although the outcome of this approach is generally good, most studies are case reports, and there is a lack of prospective cohort study for assessing the effectiveness of this method. Therefore, in this clinical trial protocol, we will assess the efficacy of transvenous embolization of draining venous unit, with the aim of helping to optimize treatment strategies for patients with intracranial arteriovenous malformations. Design: This is a prospective, single-center cohort study. Methods: We will recruit 190 patients with intracranial arteriovenous malformations from the Department of Intracranial Arteriovenous Malformation, Henan Provincial People's Hospital, China. The patients will be assigned to two groups. Participants in the control group (n = 95) will undergo conventional treatment, such as surgery, stereotactic radiosurgery and transarterial embolization. Participants in the trial group (n = 95) will receive transvenous embolization combined with conventional treatment. Outcome measures: The primary outcome measures are stroke or death within 30 days of surgery, and efficacy of treatment at 6 months postoperatively. The secondary outcome measures are the efficacy of treatment at 30 days and 24 months postoperatively, National Institutes of Health Stroke Scale scores, modified Rankin Scale scores at 1, 7 and 30 days and 3, 6, 12, 24 and 36 months postoperatively, and adverse reactions during treatment and follow-up. Discussion: Our study will provide clinical evidence for the rational use of transvenous embolization for intracranial arteriovenous malformations. Ethics and dissemination: This trial has been approved by the Medical Ethics Committee of Henan Provincial People's Hospital of China [approval number: 2017 (41)]. This trial was designed in 1 August 2017. Ethics approval was completed in 19 October 2017. This trial was registered in 11 December 2017. The recruitment of participants began in January 2018. The recruitment will be finished in January 2019. Follow-up will be completed in January 2022. Data analysis will be finished in January 2023. Trial registration: This trial had been registered in the Chinese Clinical Trial Registry (registration number: ChiCTR-OOC-17013851). Protocol version (1.0).

Endovascular treatment of small cerebral arteriovenous malformations as a primary therapy.

PurposeThe patient population that would benefit most from endovascular curative treatment of intracranial arteriovenous malformations is not clearly established. The aim of the study was to determine the effect of curative embolization of cerebral arteriovenous malformations with special regard to radiographic and clinical outcomes and procedure-related complications.Material and methodsBetween January 2009 and December 2014, 18 patients with intracranial arteriovenous malformations were embolized with Onyx with intent to cure. There were 4 women and 14 men with a mean age of 40 years (range 10-62 years). Inclusion criteria were: maximal diameter of the lesions ≤ 3 cm and arterial supply consisting of no more than 2 major arteries. There were 5 (27.8 %) patients with ruptured and 13 (72.2%) with unruptured lesions. Mean arteriovenous malformations size was 2.3 cm (range 1.5-2.9 cm).ResultsThirty-three procedures were performed in 18 patients. Total obliteration was achieved in 5 patients (27.8%). The most common reason for initial incomplete angiographic occlusion were unfavorable angioarchitectural features of arteriovenous malformations with the rate of 44.4%. The mean follow-up of patients with complete occlusion was 35.2 months (range 18-60 months). Complication rate was 12.1%. One patient had permanent neurological deficit with resulting morbidity of 5.6%. There were no deaths.ConclusionsEmbolization of intracranial arteriovenous malformations plays a limited role as a sole therapeutic modality even in terms of small lesions with two or less arterial feeders, although larger prospective series are necessary to confirm your findings. Associated complications are not trivial and should be considered when choosing this form of treatment.

Dural AVM (dAVM) in Cowden disease

Abstract Cowden disease is a rare autosomal dominant disorder first described by Rachel Cowden in 1963 as one of the phosphatase and tensin homolog (PTEN) gene hamartoma tumor syndromes. Commonly affecting multiple systems, patients typically have an increased risk of breast and thyroid cancers as well as macrocephaly and benign hamartomatous growths. Due to the benign nature of many of the symptoms, true prevalence is likely higher than reported rates. Malformations associated with PTEN gene lead to dysregulation of cell proliferation yielding increased risk of neoplasm and frequently benign growths. Associated dysregulation of angiogenesis may result in arteriovenous malformations (AVMs). Intracranial AVMs may be asymptomatic. These AVMs present a risk of rupture and subsequent morbidity and mortality. Those with Cowden disease must be monitored for development of intracranial AVMs. Patients should be made aware that treatment for intracranial AVMs may be invasive and include serial embolization.

Predicament and challenge in the treatment of intracranial arteriovenous malformation

Predicament and challenge in the treatment of intracranial arteriovenous malformation

Efficacy analysis of Onyx embolization in combination with gamma knife surgery for the treatment of intracranial arteriovenous malformation

Objective To investigate the effectiveness and safety of Onyx embolization in combination with gamma knife surgery for the treatment of intracranial arteriovenous malformations (AVMs). Methods A total of 86 patients with AVM admitted to the Neurological intervention Center, Beijing Neurosurgery Institute, Capital Medical University and treated with Onyx embolization in combination with gamma knife surgery from April 2004 to September 2011 were analyzed retrospectively. The related complications and clinical prognosis of embolization were counted and analyzed. During the embolization of AVMs, the combined high risk of bleeding (intracranial aneurysms, hemodynamic aneurysms, and AVM-related arteriovenous fistula) were assessed and embolized. According to the risk factors and embolization or not, the intracranial AVMs with high risk factors were divided into either a targeted embolization group or a non-targeted embolization group. The effect of targeted embolization on hemorrhage risk was assessed. Results The overall annual hemorrhage rate in patients with AVM was 1.66%, and the ruptured AVM was 2.26%, the unruptured AVM was 1.08%, and the annual mortality rate was 0.74%. One of 16 patients with embolization related complications had permanent neurological dysfunction. Twenty-four of 29 patients complicated with intranidal aneurysm underwent targeted embolization; 4 of 5 patients with hemodynamic aneurysm underwent targeted embolization; and 8 of 9 patients with arteriovenous fistula underwent targeted embolization. Chi square test showed that the hemorrhage complications of the targeted embolization group was significantly lower than that of the non-targeted embolization group (P<0.01). Conclusion The targeted embolization in combination with gamma knife surgery may decrease the risk of intracranial AVM hemorrhage, improve clinical prognosis and occur less permanent complications. This method is suitable for the treatment of intracranial AVMs of larger volume and those can not be cured with a single program. Key words: Intracranial arteriovenous malformations; Cerebral angiography; Radiotherapy; Hemorrhage; Postoperative complication

Strategies on the treatment of intracranial arteriovenous malformations

Surgical treatment of intracranial arteriovenous malformation (AVM) is one of the most difficult tasks for neurosurgeons, especially, for patients with large size AVM or AVM at the eloquent and deep location. Recent advent of endovascular treatment and radiosurgery may replace the role of surgery and decrease the difficulty of treatment of AVM to some extend but not all. Surgical excision with or without preoperative embolization remains the main modality of treatment of intracranial AVMs. However, the procedure of embolization itself also carries certain percentage of risk. Selection of this treatment modality needs to be carefully evluated.For small deep seated AVM and small AVM at the eloquent area, radiosurgery is another therapeutic option. However, the efficacy to achieve obliteration of the AVM by radiosurgery is only 60%-70% in general. Combined embolization and radiosurgery has been advocated as an option for treating large complex AVM. However, current treatment results failed to demonstrate any superiority of the result from this combined treatment.Palliative treatment with partial obliteration of the AVM nidus toreduce arteriovenous shunting is considered to be useful for the decrease of the occurrence of steal phenomenon, however, it may also increase shear stress of the abnormal vascular architecture and resulted in increase rate of hemorrhage.From 1989 to 2011, a total of 367 patients with cerebral AVM were treated at the National Taiwan University Hospital and its’ affiliate hospitals. Of these 367 patients, 143 patients underwent microsurgery as the solo treatment and 214 patients received embolization. In the later group, 25 patients had their AVMs cured after one or multiple sessions of endovascular treatment. The other 189 patients in this group, endovascular treatment can only be applied for the reduction of the flow and the size of the AVM. These patients finally underwent microsurgery as the definite treatment. The treatment morbidity was 11% in microsurgical group and 9% inendovascular group. There were 2 mortalities in surgical group (o.6 %) and 2 in endovascular group (0.9 %).Our current selection criteria for different therapeutic modality and surgical strategy for intracranial AVM will be discussed. Surgical treatment of intracranial arteriovenous malformation (AVM) is one of the most difficult tasks for neurosurgeons, especially, for patients with large size AVM or AVM at the eloquent and deep location. Recent advent of endovascular treatment and radiosurgery may replace the role of surgery and decrease the difficulty of treatment of AVM to some extend but not all. Surgical excision with or without preoperative embolization remains the main modality of treatment of intracranial AVMs. However, the procedure of embolization itself also carries certain percentage of risk. Selection of this treatment modality needs to be carefully evluated. For small deep seated AVM and small AVM at the eloquent area, radiosurgery is another therapeutic option. However, the efficacy to achieve obliteration of the AVM by radiosurgery is only 60%-70% in general. Combined embolization and radiosurgery has been advocated as an option for treating large complex AVM. However, current treatment results failed to demonstrate any superiority of the result from this combined treatment. Palliative treatment with partial obliteration of the AVM nidus toreduce arteriovenous shunting is considered to be useful for the decrease of the occurrence of steal phenomenon, however, it may also increase shear stress of the abnormal vascular architecture and resulted in increase rate of hemorrhage. From 1989 to 2011, a total of 367 patients with cerebral AVM were treated at the National Taiwan University Hospital and its’ affiliate hospitals. Of these 367 patients, 143 patients underwent microsurgery as the solo treatment and 214 patients received embolization. In the later group, 25 patients had their AVMs cured after one or multiple sessions of endovascular treatment. The other 189 patients in this group, endovascular treatment can only be applied for the reduction of the flow and the size of the AVM. These patients finally underwent microsurgery as the definite treatment. The treatment morbidity was 11% in microsurgical group and 9% inendovascular group. There were 2 mortalities in surgical group (o.6 %) and 2 in endovascular group (0.9 %). Our current selection criteria for different therapeutic modality and surgical strategy for intracranial AVM will be discussed.

Treatment of Brain Arteriovenous Malformations With Stereotactic Radiosurgery Following Embolization

Treatment of intracranial arteriovenous malformations (AVMs) is complex and multimodal. Some series have suggested embolization (embo) followed by stereotactic radiosurgery (SRS) is associated with poor outcomes. We examine the effect of post-embo SRS for AVMs.

Clinical features and endovascular treatment of intracranial arteriovenous malformations in pediatric patients

The purpose of this study was to characterize clinical features and evaluate the clinical outcome of endovascular embolization treatment intracranial arteriovenous malformations in pediatric patients. A cohort of children (age ≤ 18 years) with arteriovenous malformations (AVMs) from 2000 to 2012 was included. Predictors studied included patient gender, age, and angioarchitectural features, including AVM location, nidus morphology and size, venous drainage, and associated aneurysms. Treatment method, complications and outcomes were recorded. The features of AVMs were evaluated before the treatment. One hundred twenty-seven children (77 males, mean age 13.2 years) were included; 90/127 (70.9 %) children were presented with hemorrhage. AVM size and deep venous drainage were independently associated with hemorrhage; 66/127 patients (52 %) treated with endovascular embolization. Complete obliteration at the end of all endovascular procedures was achieved in 14/66 patients (21.2 %), with an average of 78 % (range, 20-100 %) volume reduction. A mean of 2.9 (range, 1-9) feeding pedicles was embolized per patient. Overall, nine complications occurred in a total of 123 procedures (7.3 %). There was no procedure-related death in this study population. There was no significant difference between patients with and without complications in terms of AVM grade, demographic characteristics, or embolization features. AVM size and deep venous drainage were independently associated with hemorrhage in pediatric patients. Endovascular procedure is feasible and safe for pediatric AVMs, and complete embolization can be achieved in small AVMs, while large AVMs can be adequately reduced in size for additional microsurgery or stereotactic radiosurgery.

Evaluation of surgical treatment for intracranial arteriovenous malformations

The main purpose of the treatment of intracranial arteriovenous malformations (AVMs) is complete obliteration of the nidus to prevent primary or recurrent intracranial hemorrhage and protect neurological functions maximally. Currently, microsurgical resection, endovascular embolization, or stereotactic radiosurgery are the most commonly used therapies which are utilized either alone or in combination. This study will discuss the pros and cons of the three therapeutic methods of AVMs in order to determine the optimal treatment. The choice of a multimodality treatment should follow the principle of improving the cure rate and avoiding complications as much as possible.

Onyx embolization of intracranial arteriovenous malformations in pediatric patients

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. 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. 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). 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.

Population-Based Estimates of Neuroendovascular Procedures: Results of a State-Wide Study

Background: The Brain Attack Coalition identified the availability of neuroendovascular procedures as an essential component of a comprehensive stroke center. Objective: To provide population-based estimates of neuroendovascular procedures. Methods: State-wide estimates of cervicocerebral angiograms, endovascular ischemic stroke treatments, carotid angioplasty and stent placements, intracranial angioplasty and stent placements, endovascular treatment of intracranial aneurysms, and endovascular treatment of intracranial arteriovenous malformations (AVMs) were obtained. We calculated the annual incidence rates of various neuroendovascular and neurosurgical procedures (per 100,000 persons). For the denominator, total persons in each year were categorized in 10-year age intervals. Results: The incidence of carotid endarterectomy (387.6 per 100,000 persons) and carotid stent placement (34.7 per 100,000 persons) peaked at 75–84 years. The incidence of aneurysm embolization also peaked in that population bracket (67.9 per 100,000 persons), yet there was a dramatic reduction in the incidence of surgical aneurysm treatment (3.6 per 100,000 persons) in those aged 75–84 years. There was a prominent reduction in the incidence of all procedures in the population aged ≥85 years, except for intravenous/intra-arterial thrombolytic use in ischemic stroke. The incidence of ischemic stroke increased almost by 50% in the population aged ≥85 years compared to those aged 75–84 years. However, the incidence of endovascular procedures for acute ischemic stroke decreased from 22.8 per 100,000 persons in the population aged 75–84 years to 13.2 per 100,000 persons in the population aged ≥85 years. Conclusions: A marked disproportion of neuroendovascular procedures performed and disease prevalence was noted in persons aged ≥85 years, an increasing segment of the population according to recent Census.

Repeat Radiosurgery for Intracranial Arteriovenous Malformations

Despite a high success rate in the stereotactic radiosurgical treatment of intracranial arteriovenous malformations (AVMs) that cannot be safely resected with microsurgery, some patients must be managed after treatment failure. To provide an update on the use of repeat linear accelerator radiosurgery as a treatment for failed AVM radiosurgery at the University of Florida. We reviewed 103 patients who underwent repeat radiosurgical treatment for residual AVM at the University of Florida between December 1991 and December 2007. Each of these patients had at least 2 radiosurgical treatments for the same AVM. Patient information, including AVM nidus volume, prescription dose, age, and sex, was collected at the time of initial treatment and again at the time of retreatment. Patients were followed up after treatment with magnetic resonance, computed tomography, and angiographic imaging at standard intervals to determine the status of their AVM. The median follow-up after retreatment was 31 months. Between the first and second treatments, the median AVM nidus volume was decreased by 69% (from a median volume of 12.7 to 4.0 cm), allowing the median prescribed dose to be increased from 1500 cGy on initial treatment to 1750 cGy on retreatment. The final obliteration rate on retreatment was 65.3%. After salvage retreatment, 5 patients (4.9%) experienced radiation-induced complications, and 6 patients (5.8%) experienced posttreatment hemorrhage. Repeat radiosurgery is a safe and effective salvage treatment for AVMs.

O-012 Onyx embolization of intracranial arteriovenous malformations in pediatric patients

ObjectiveThe use of ethylene-vinyl alcohol copolymer (Onyx) in the treatment of intracranial arteriovenous malformations (AVMs) has increased the cure rate of endovascular embolization compared with the use of liquid adhesive...