Low-grade Arteriovenous Malformations Research Articles

Primary Embolization of Cerebral Arteriovenous Malformations With Intention to Cure: A Systematic Review of Literature and Meta-Analysis.

The treatment of brain arteriovenous malformations (AVMs) involves multiple approaches, including embolization, microsurgical resection, and radiosurgery. With the advent of new embolisates, dual-lumen balloon catheters, detachable tip microcatheters, and transvenous embolization, endovascular AVM obliteration has become more effective. Although adjuvant embolization and embolization are commonly used, the safety and effectiveness of curative embolization remain unclear. We conducted a systematic literature review using PubMed, Ovid Medline, and Web of Science to identify studies reporting outcomes in patients with AVMs who underwent primary embolization with the intention to cure. We collected data on patient characteristics, AVM features, complications, and radiographic and clinical outcomes for meta-analysis. We identified 25 studies with a total of 1425 patients with 1427 AVMs who underwent curative embolization. Of these patients, 70% were low grade (pooled = 61% [39-82]), 67% were <3 cm (pooled = 78% [60-92]), and 75% were in superficial locations (pooled = 80% [72-86]). At last radiographic follow-up (mean, 16.7 ± 10.9 months), the full obliteration rate was 52% (pooled = 61% [43-77]) and retreatment rate was 25% (pooled = 17% [8.3-27]). At last clinical follow-up (mean, 24.2 ± 13.3 months), the poor clinical outcome rate was 7.9% (pooled = 4.4% [1.3-8.7]) and symptomatic complication rate was 13% (pooled = 13% [8-19]). There was no significant difference in the rate of radiographic cure, need for retreatment, and poor outcomes between ruptured and unruptured AVMs. Symptomatic complications were more common in the treatment of unruptured AVMs. The primary outcomes showed high heterogeneity (I2 = 72%-94%). Curative embolization of AVM is primarily reserved for small and low-grade AVMs, with highly variable outcomes. Our findings suggest poor radiographic outcomes and increased risk of complications. Outcomes are highly dependent on patient selection and technique used. Large multicenter prospective studies are required to further guide patient selection, categorize clinical and radiographic outcomes, and identify subgroup of patients that may benefit from curative embolization.

Outcomes of Microsurgical Resection of Low-Grade Cerebral Arteriovenous Malformations: A Prospective Observational Multicenter Study from a Low-Middle-Income Country

ObjectiveTo appraise the overall outcomes of microsurgical resection of low-grade arteriovenous malformations (AVMs) in a low-middle-income country. MethodsData was collected prospectively from three different neurosurgical centres in Pakistan for this study and it lasted for two years. According to the Spetzler-Martin (S-M) grading system, patients diagnosed with cerebral AVMs were divided into three classes A, B, and C. AVMs of grade 1 and 2 were included in Class A. Class B contained grade 3 AVMs, while Class C contained grade 4 and 5 AVMs. All male and female patients in Class A were eligible for this study. Patients were evaluated postoperatively for seizures, haemorrhage, focal neurological deficits, and AVM cure rates. Morbidity, mortality, and functional recovery were used to evaluate the outcome. Functional recovery and cure rate were observed after 6 months of follow-up. ResultsThere were a total of 22 patients. Mean age was 36.41 ± 14.32 SD years. There were 12 (54.5 %) male patients and 10 (45.5 %) female patients. 13 patients (59.1 %) presented with spontaneous intracerebral haemorrhage, while 9 patients (40.9 %) presented with seizures. 14 patients (63.6 %) had S-M grade 1 and 8 patients (36.4 %) had S-M grade 2. All patients underwent microsurgical resection. We discovered 4.5 % morbidity in our study. There was no postoperative mortality. At 6 months, an excellent functional outcome of 95.5 % (according to the Glasgow outcome scale) and 100 % cure rate was observed. ConclusionMicrosurgery is a safe and effective treatment for low-grade AVMs in terms of morbidity, mortality, functional outcome and cure rates in our country.

Prophylactic Awake Peripheral VA ECMO TAVI Is Safe and Effective: A Case Series and Patient Management Algorithm

Sylvian arteriovenous malformations (sAVMs) are rare and account for approximately 8%–11% of all intracranial arteriovenous malformations (AVMs).1 Because of their proximity to eloquent structures such as the motor speech center, insular cortex, and internal capsule, microsurgical resection of sAVMs remains a challenge.Several classifications have already been suggested for sAVMs, such as Sugita and Yasargil.1,2 It is well established that for low-grade AVMs, results of the microsurgical resection are excellent and tend to favor surgery,1, 2, 3 but in high-grade AVM, a multimodal assessment is necessary for formulating treatment strategies.1In Video 1, we demonstrate the surgical resection of a ruptured sylvian temporal AVM. This AVM was localized in the superior surface of the temporal lobe, and its nidus was just beneath the cortical surface of this lobe. Because it was 5.1 cm at its largest diameter, had a deep drainage vein, and was localized adjacent to the Wernicke area, we classified it as a Spetzler-Martin grade IV AVM.4Despite the high-grade AVM, microsurgical treatment was the choice in this ruptured AVM and there was no increase in morbidity.

Topical Drug Application to Treat Infective Endocarditis – Preclinical Investigation of Novel Therapeutic Options for an Unmet Medical Need

Sylvian arteriovenous malformations (sAVMs) are rare and account for approximately 8%–11% of all intracranial arteriovenous malformations (AVMs).1 Because of their proximity to eloquent structures such as the motor speech center, insular cortex, and internal capsule, microsurgical resection of sAVMs remains a challenge.Several classifications have already been suggested for sAVMs, such as Sugita and Yasargil.1,2 It is well established that for low-grade AVMs, results of the microsurgical resection are excellent and tend to favor surgery,1, 2, 3 but in high-grade AVM, a multimodal assessment is necessary for formulating treatment strategies.1In Video 1, we demonstrate the surgical resection of a ruptured sylvian temporal AVM. This AVM was localized in the superior surface of the temporal lobe, and its nidus was just beneath the cortical surface of this lobe. Because it was 5.1 cm at its largest diameter, had a deep drainage vein, and was localized adjacent to the Wernicke area, we classified it as a Spetzler-Martin grade IV AVM.4Despite the high-grade AVM, microsurgical treatment was the choice in this ruptured AVM and there was no increase in morbidity.

Microsurgical Treatment of Deep and Eloquent AVMs.

Over the past 30years, the treatment of deep and eloquent arteriovenous malformations (AVMs) has moved away from microneurosurgical resection and towards medical management and the so-called minimally invasive techniques, such as endovascular embolization and radiosurgery. The Spetzler-Martin grading system (and subsequent modifications) has done much to aid in risk stratification for surgical intervention; however, the system does not predict the risk of hemorrhage nor risk from other interventions. In more recent years, the ARUBA trial has suggested that unruptured AVMs should be medically managed. In our experience, although these eloquent regions of the brain should be discussed with patients in assessing the risks and benefits of intervention, we believe each AVM should be assessed based on the characteristics of the patient and the angio-architecture of the AVM, in particular venous hypertension, which may guide us to treat even high-grade AVMs when we believe we can (and need to) to benefit the patient. Advances in imaging and intraoperative adjuncts have helped us in decision making, preoperative planning, and ensuring good outcomes for our patients. Here, we present several cases to illustrate our primary points that treating low-grade AVMs can be more difficult than treating high-grade ones, mismanagement of deep and eloquent AVMs at the behest of dogma can harm patients, and the treatment of any AVM should be tailored to the individual patient and that patient's lesion.

Effects of Preoperative Embolization on Spetzler-Martin Grade I and II Arteriovenous Malformations: A Propensity-Adjusted Analysis.

Cerebral arteriovenous malformations (AVMs) with low Spetzler-Martin grades (I and II) are associated with good neurological outcomes after microsurgical resection; however, the use of preoperative embolization for these lesions is controversial. To compare the neurological outcomes of preoperative embolization with no embolization in patients with low-grade AVMs. Patients with a Spetzler-Martin grade I or II AVM who underwent microsurgical resection during January 1, 1997, through December 31, 2019, were analyzed. Patients undergoing preoperative embolization were compared with patients not undergoing embolization. A propensity score was constructed from baseline characteristics and used to match intervention (embolization) and control (nonembolization) groups in a 1:1 ratio. The primary outcome was poor neurological status on last follow-up examination, defined as a modified Rankin Scale score >2 and a modified Rankin Scale score worse at follow-up than at the preoperative examination. Of the 603 patients analyzed, 310 (51.4%) underwent preoperative embolization and 293 (48.6%) did not. Patients in the embolization cohort compared with those in the nonembolization cohort had a higher percentage of Spetzler-Martin grade II AVMs (71.6% vs 52.6%, P < .001) and a lower percentage of hemorrhage (41% vs 55%, P = .001). After propensity score matching, no differences were found between paired cohorts (each N = 203) for baseline characteristics with a significant reduction in absolute standardized mean differences. No significant differences were found in primary outcomes between treatment groups in the matched or unmatched cohorts. Preoperative embolization of low-grade Spetzler-Martin AVMs is not associated with improved neurological outcomes after microsurgical resection.

Microsurgical resection versus stereotactic radiosurgery for low-grade intracranial arteriovenous malformations: A 27-year institutional experience

The role of microsurgery and radiosurgery in the management of low-grade (Spetzler-Martin grade 1 and 2) arteriovenous malformations (AVMs) remains controversial. We aimed to compare outcomes of low-grade AVMs following microsurgery and radiosurgery using a database of AVM patients presenting between 1990 and 2017. Procedure-related complications, obliteration, and functional status at last follow-up were compared between groups. Hemorrhage-free survival was compared using Kaplan-Meier analysis with subgroup analyses by rupture status on presentation. The study involved 233 patients, of which 113 and 120 were treated with microsurgery and radiosurgery, respectively. The complication rates were statistically comparable between both treatment modalities. Mean follow-up time was 5.1 ± 5.2 years. In the complete cohort, there was no significant difference in hemorrhage-free survival between microsurgery and radiosurgery (log-rank p = 0.676, Breslow p = 0.493). When excluding procedure-related hemorrhage and partial resection, hemorrhage-free survival was significantly higher in the surgically treated cohort (log-rank = 0.094, Breslow p = 0.034). The obliteration rate was significantly higher in the surgical cohort (96% vs. 57%, p < 0.001), while functional status was similar. Microsurgery may offer superior hemorrhage-free survival in the early post-treatment period and demonstrates equivalent long-term hemorrhage control and functional outcome at 5 years compared to radiosurgery with nearly complete obliteration rates. Persistent neurologic deficits following microsurgery and symptomatic cerebral edema represent important treatment risks despite low SM grading. Appropriate patient selection even when dealing with low-grade AVMs is advised, as judicious patient selection and emphasis on technical success can minimize procedure-related hemorrhage and the incidence of subtotal resection.

Microsurgical approach for symptomatic brain AVMs – single center experience

ABSTRACT Objectives: Brain arteriovenous malformations (AVMs) represent high-flow vascular lesions made up of a complex network of feeding arteries and draining veins interposed by a nidus and without a capillary bed. The management of the AVMs represents a challenge, and the optimal treatment should be considered based on the particularities of each AVM. This paper aims to provide outcome data for the cohort of patients with AVMs that underwent surgical treatment. Methods: A retrospective review of patients who presented with AVMs between 2001 and 2019 was conducted. Patients were included if they underwent surgery, preoperative and postoperative angiographic studies were available. Results: 91 patients were included. The SM grade was 1 in 16 cases (17,6%), 2 in 27 patients (29.7%), 3 in 29 patients (31,9%), 4 in 12 cases (13.2%) and grade 5 in 7 cases (7.7%). In 58 (63.7%) cases the AVMs were ruptured. Complete microsurgical resection was achieved in 82 cases (90.1%). Unruptured AVM (87.9% vs. 63.8% for ruptured AVMs; p = 0.015), low-grade AVM (86% vs. 60.4% for grade III–V AVMs; p = 0.006) and cortical location (79.5% vs. 30.8% for deep AVM; p < 0.0001) were the factors associated with a good outcome on mRS scale. Conclusions: Microsurgical resection is the curative treatment for AVMs and offers a good functional outcome if selection criteria are met.

Combined (microsurgical and endovascular) treatment of cerebral arteriovenous malformations

Objective – to analyze the results of combined microsurgical and endovascular treatment of brain arteriovenous malformations (AVM).Materials and methods. Radiological and clinical data of 19 patients who underwent preoperative endovascular embolization and resection of the AVM at the SO «Scientific-practical Center of endovascular neuroradiology NAMS of Ukraine» in 2014–2019 were analyzed. Among patients were 11 (57.9 %) women and 8 (42.1 %) men. The average age of patient was 28.4 year (from 15 to 54 years). All AVMs were I–III grade according to the Spetzler–Martin scale.Results. The average AVM size in its maximum dimension was 3.2 cm (range 3.1–6.8 cm). 14 (73.7 %) AVMs were supratentorial and 5 (26.3 %) – subtentorial, in 9 (47.4 %) cases AVMs were located in eloquent areas of the brain, in 1 (5.3 %) – in the motor area. Cerebral or subarachnoid hemorrhage were observed in 12 (63.2 %) cases, seizures – in 4 (21.1 %), headache not associated with bleeding – in 2 (10.5 %) and neurological deficiency not related to the bleeding – in 1 (3.7 %). In 16 (84.2 %) patients total AVM resection was achieved, 3 (15.8 %) patients underwent subtotal resection. Fourteen (73.7 %) patients had good results at discharge (10 (52.6 %) patients had 0 or 1 according to modified Rankin score, and 4 (21.1%) patients had 2), 5 (26.3 %) – 3 and 4. There were no mortality cases after combined endovascular and microsurgical treatment. Onset of new neurological deficits occurred in 5 (26.3 %) patients, and in 3 (15.8 %) cases it regress at discharge and in 2 (10.5 %) cases was permanent.Conclusions. Combined treatment (endovascular embolization and microsurgical resection) of AVMs of the low grade AVM (I–III grade of the Spetzler–Martin scale) allows achieving good treatment results. The use of preoperative endovascular embolization reduces blood flow through the AVM and prevents postoperative hemodynamic overload, intraoperative and/or postoperative bleeding.

Curative treatment for low-grade arteriovenous malformations

BackgroundSpetzler-Martin (SM) grade I-II (low-grade) arteriovenous malformations (AVMs) are often considered safe for microsurgery or radiosurgery. The adjunctive use of preoperative embolization to reduce surgical risk in these AVMs remains...

The future of open vascular neurosurgery: perspectives on cavernous malformations, AVMs, and bypasses for complex aneurysms.

Despite the erosion of microsurgical case volume because of advances in endovascular and radiosurgical therapies, indications remain for open resection of pathology and highly technical vascular repairs. Treatment risk, efficacy, and durability make open microsurgery a preferred option for cerebral cavernous malformations, arteriovenous malformations (AVMs), and many aneurysms. In this paper, a 21-year experience with 7348 cases was reviewed to identify trends in microsurgical management. Brainstem cavernous malformations (227 cases), once considered inoperable and managed conservatively, are now resected in increasing numbers through elegant skull base approaches and newly defined safe entry zones, demonstrating that microsurgical techniques can be applied in ways that generate entirely new areas of practice. Despite excellent results with microsurgery for low-grade AVMs, brain AVM management (836 cases) is being challenged by endovascular embolization and radiosurgery, as well as by randomized trials that show superior results with medical management. Reviews of ARUBA-eligible AVM patients treated at high-volume centers have demonstrated that open microsurgery with AVM resection is still better than many new techniques and less invasive approaches that are occlusive or obliterative. Although the volume of open aneurysm surgery is declining (4479 cases), complex aneurysms still require open microsurgery, often with bypass techniques. Intracranial arterial reconstructions with reimplantations, reanastomoses, in situ bypasses, and intracranial interpositional bypasses (third-generation bypasses) augment conventional extracranial-intracranial techniques (first- and second-generation bypasses) and generate innovative bypasses in deep locations, such as for anterior inferior cerebellar artery aneurysms. When conventional combinations of anastomoses and suturing techniques are reshuffled, a fourth generation of bypasses results, with eight new types of bypasses. Type 4A bypasses use in situ suturing techniques within the conventional anastomosis, whereas type 4B bypasses maintain the basic construct of reimplantations or reanastomoses but use an unconventional anastomosis. Bypass surgery (605 cases) demonstrates that open microsurgery will continue to evolve. The best neurosurgeons will be needed to tackle the complex lesions that cannot be managed with other modalities. Becoming an open vascular neurosurgeon will be intensely competitive. The microvascular practice of the future will require subspecialization, collaborative team effort, an academic medical center, regional prominence, and a large catchment population, as well as a health system that funnels patients from hospital networks outside the region. Dexterity and meticulous application of microsurgical technique will remain the fundamental skills of the open vascular neurosurgeon.

General Principles for Preoperative Planning and Microsurgical Treatment of Pediatric Brain Arteriovenous Malformations: 2-Dimensional Operative Video.

Children with arteriovenous malformations (AVMs) are at cumulative, life-long risk of debilitating and fatal intracranial hemorrhage, especially with syndromes such as hereditary hemorrhagic telangiectasia. Cerebral angiography is the gold standard for diagnosis and allows simultaneous adjunctive embolization limiting radiation and contrast exposure and intraoperative blood loss, important in pediatric patients with low blood volume. Microsurgical resection of low-grade AVMs offers cure with minimal morbidity. The plasticity of the pediatric brain may allow resection of AVMs near eloquent regions. Multidisciplinary care offers the best outcomes in these cases. Discussion of the operative plan with all team members at the start of surgery is carried out. Confirmation that blood products are present and that the microscope, additional suction, and surgical clips are available is performed. A generous craniotomy is created, adequately exposing the lesion. The dura is carefully opened to avoid injury to draining veins. Circumferential dissection and isolation of the AVM is performed, coagulating small arterial feeders, dissecting to the lesion's apex to coagulate, and divide major deep feeders. Once all feeders have been obliterated, venous drainage is disconnected. Indocyanine green distinguishes arterial feeders from arterialized veins and confirms complete resection. Since 2008, all of our patients undergo perioperative angiography in our dedicated suite, greatly improving resection rates. Strict blood pressure control and close neurological monitoring in the intensive care unit is performed postoperatively. In conclusion, microsurgical resection of AVMs can be performed safely with low rates of morbidity. Protocols for preoperative evaluation and planning appear to improve outcomes. Anonymous video is permitted when done without identifying patient related information.

Grades of brain arteriovenous malformations and risk of hemorrhage and death.

ObjectiveTo assess the relationship of the grade of unruptured and untreated Brain Arteriovenous Malformations (AVMs), with the risk of subsequent stroke and death during follow‐up.MethodsThis prospective study was drawn from a cohort of adult patients with unruptured AVMs, who participated in the conservative treatment arm (medical management only for headache or seizures) of the randomized clinical trial of unruptured brain AVMs (ARUBA study). The grade of AVMs (Spetzler–Martin scale) was dichotomized into categories: AVMs of grades I and II were considered low grade; AVMs of grades III and IV were considered high grade. There were no grade V AVM patients in ARUBA. The primary outcome was symptomatic stroke (hemorrhagic or ischemic – documented by imaging) or death.ResultsThe conservative treatment group had 123 patients (“as treated” analysis). 71 (57.7%) had lesions characterized for this analysis as low‐grade lesions and 52 (42.2%) as high grade. From the total of 10 (8.13%) primary outcomes, three occurred (4.22%) in low‐grade AVMs and seven (13.46%) in high‐grade AVMs (P = 0.0942).InterpretationStatistical analysis of the cohort of patients with unruptured and untreated AVMs from ARUBA study showed that the graduation categories (Spetzler–Martin grades) were not associated with the outcome of subsequent stroke or death.

Linear Accelerator Stereotactic Radiosurgery of Central Nervous System Arteriovenous Malformations: A 15-Year Analysis of Outcome-Related Factors in a Single Tertiary Center.

Linear accelerator stereotactic radiosurgery is one of the modalities available for the treatment of central nervous system arteriovenous malformations (AVMs). The aim of this study was to describe our 15-year experience with this technique in a single tertiary center and the analysis of outcome-related factors. From 1998 to 2013, 195 patients were treated with linear accelerator-based radiosurgery; we conducted a retrospective study collecting patient- and AVM-related variables. Treatment outcomes were obliteration, posttreatment hemorrhage, symptomatic radiation-induced changes, and 3-year neurologic status. We also analyzed prognostic factors of each outcome and predictability analysis of 5 scales: Spetzler-Martin grade, Lawton-Young supplementary and Lawton combined scores, radiosurgery-based AVM score, Virginia Radiosurgery AVM Scale, and Heidelberg score. Overall obliteration rate was 81%. Nidus diameter and venous drainage were predictive of obliteration (P < 0.05), ruptured status and previous embolization were not related to rate of obliteration, and low-grade AVMs had higher obliteration rates. Posttreatment hemorrhage incidence was 8.72%; nidus diameter was the only predictor (P= 0.05). Symptomatic radiation-induced changes occurred in 11.79% of patients and were significantly associated with unruptured status (P < 0.05). Treatment success as a composite measure was obtained in 70.77% of patients. Receiver operating characteristic curves were presented for each scoring system and outcome measure; best area under the curve was 0.687 for Lawton combined score in the obliteration outcome. In the long-term, linear accelerator-based radiosurgery is a useful, valid, effective, and safe modality for treatment of brain AVMs.

Stereotactic Radiosurgery for ARUBA (A Randomized Trial of Unruptured Brain Arteriovenous Malformations)-Eligible Spetzler-Martin Grade I and II Arteriovenous Malformations: A Multicenter Study.

ARUBA (A Randomized Trial of Unruptured Brain Arteriovenous Malformations) found better short-term outcomes after conservative management compared with intervention for unruptured arteriovenous malformations (AVMs). However, because Spetzler-Martin (SM) grade I-II AVMs have the lowest treatment morbidity, sufficient follow-up of these lesions may show a long-term benefit from intervention. The aim of this multicenter, retrospective cohort study is to assess the outcomes after stereotactic radiosurgery (SRS) for ARUBA-eligible SM grade I-II AVMs. We pooled SRS data for patients with AVM from 7 institutions and selected ARUBA-eligible SM grade I-II AVMs with ≥12 months follow-up for analysis. Favorable outcome was defined as AVM obliteration, no post-SRS hemorrhage, and no permanently symptomatic radiation-induced changes. The ARUBA-eligible SM grade I-II AVM cohort comprised 232 patients (mean age, 42 years). The mean nidus volume, SRS margin dose, and follow-up duration were 2.1 cm3, 22.5 Gy, and 90.5 months, respectively. The actuarial obliteration rates at 5 and 10 years were 72% and 87%, respectively; annual post-SRS hemorrhage rate was 1.0%; symptomatic and permanent radiation-induced changes occurred in 8% and 1%, respectively; and favorable outcome was achieved in 76%. Favorable outcome was significantly more likely in patients treated with a margin dose >20 Gy (83%) versus ≤20 Gy (62%; P < 0.001). Stroke or death occurred in 10% after SRS. For ARUBA-eligible SM grade I-II AVMs, long-term SRS outcomes compare favorably with the natural history. SRS should be considered for adult patients harboring unruptured, previously untreated low-grade AVMs with a minimum life expectancy of a decade.

Surgical Strategies for Acutely Ruptured Arteriovenous Malformations.

Brain arteriovenous malformations (AVMs) are focal neurovascular lesions consisting of abnormal fistulous connections between the arterial and venous systems with no interposed capillaries. This arrangement creates a high-flow circulatory shunt with hemorrhagic risk and hemodynamic abnormalities. While most AVMs are asymptomatic, they may cause severe neurological complications and death. Each AVM carries an annual rupture risk of 2-4%. Intracranial hemorrhage due to AVM rupture is the most common initial manifestation (up to 70% of presentations), and it carries significant morbidity and mortality. This complication is particularly important in the young and otherwise healthy population, in whom AVMs cause up to one-third of all hemorrhagic strokes. A previous rupture is the single most important independent predictor of future hemorrhage. Current treatment modalities for AVM are microsurgery, endovascular embolization, and radiosurgery. In acutely ruptured AVMs, early microsurgical excision is usually avoided. The standard is to wait at least 4 weeks to allow for patient recovery, hematoma liquefaction, and inflammatory reactions to subside. Exceptions to this rule are small, superficial, low-grade AVMs with elucidated angioarchitecture, for which early simultaneous hematoma evacuation and AVM excision is feasible. Emergent hematoma evacuation with delayed AVM excision (unless, as mentioned, the AVM is low grade) is recommended in patients with a decreased level of consciousness due to intracranial hemorrhage, posterior fossa or temporal lobe hematoma of >30 ml, or hemispheric hematoma of >60 ml. The applicability of endovascular techniques for acutely ruptured AVMs is not clear, but feasible options, until a definitive treatment is determined, include occluding intranidal and distal flow-related aneurysms and 'sealing' any rupture site or focal angioarchitectural weakness when one can be clearly identified and safely accessed. Radiosurgery is not performed in acutely ruptured AVMs because its therapeutic effects occur in a delayed fashion.

Current surgical results with low-grade brain arteriovenous malformations.

Resection is an appealing therapy for brain arteriovenous malformations (AVMs) because of its high cure rate, low complication rate, and immediacy, and has become the first-line therapy for many AVMs. To clarify safety, efficacy, and outcomes associated with AVM resection in the aftermath of A Randomized Trial of Unruptured Brain AVMs (ARUBA), the authors reviewed their experience with low-grade AVMs-the most favorable AVMs for surgery and the ones most likely to have been selected for treatment outside of ARUBA's randomization process. A prospective AVM registry was searched to identify patients with Spetzler-Martin Grade I and II AVMs treated using resection during a 16-year period. Of the 232 surgical patients included, 120 (52%) presented with hemorrhage, 33% had Spetzler-Martin Grade I, and 67% had Grade II AVMs. Overall, 99 patients (43%) underwent preoperative embolization, with unruptured AVMs embolized more often than ruptured AVMs. AVM resection was accomplished in all patients and confirmed angiographically in 218 patients (94%). There were no deaths among patients with unruptured AVMs. Good outcomes (modified Rankin Scale [mRS] score 0-1) were found in 78% of patients, with 97% improved or unchanged from their preoperative mRS scores. Patients with unruptured AVMs had better functional outcomes (91% good outcome vs 65% in the ruptured group, p = 0.0008), while relative outcomes were equivalent (98% improved/unchanged in patients with ruptured AVMs vs 96% in patients with unruptured AVMs). Surgery should be regarded as the "gold standard" therapy for the majority of low-grade AVMs, utilizing conservative embolization as a preoperative adjunct. High surgical cure rates and excellent functional outcomes in patients with both ruptured and unruptured AVMs support a dominant surgical posture for low-grade AVMS, with radiosurgery reserved for risky AVMs in deep, inaccessible, and highly eloquent locations. Despite the technological advances in endovascular and radiosurgical therapy, surgery still offers the best cure rate, lowest risk profile, and greatest protection against hemorrhage for low-grade AVMs. ARUBA results are influenced by a low randomization rate, bias toward nonsurgical therapies, a shortage of surgical expertise, a lower rate of complete AVM obliteration, a higher rate of delayed hemorrhage, and short study duration. Another randomized trial is needed to reestablish the role of surgery in unruptured AVM management.

Radiosurgery for low-grade intracranial arteriovenous malformations

Low-grade, or Spetzler-Martin (SM) Grades I and II, arteriovenous malformations (AVMs) are associated with lower surgical morbidity rates than higher-grade lesions. While radiosurgery is now widely accepted as an effective treatment approach for AVMs, the risks and benefits of the procedure for low-grade AVMs, as compared with microsurgery, remain poorly understood. The authors of this study present the outcomes for a large cohort of low-grade AVMs treated with radiosurgery. From an institutional radiosurgery database comprising approximately 1450 AVM cases, all patients with SM Grade I and II lesions were identified. Patients with less than 2 years of radiological follow-up, except those with complete AVM obliteration, were excluded from analysis. Univariate and multivariate Cox proportional-hazards and logistic regression analyses were used to determine factors associated with obliteration, radiation-induced changes (RICs), and hemorrhage following radiosurgery. Five hundred two patients harboring low-grade AVMs were eligible for analysis. The median age was 35 years, 50% of patients were male, and the most common presentation was hemorrhage (47%). The median AVM volume and prescription dose were 2.4 cm(3) and 23 Gy, respectively. The median radiological and clinical follow-up intervals were 48 and 62 months, respectively. The cumulative obliteration rate was 76%. The median time to obliteration was 40 months, and the actuarial obliteration rates were 66% and 80% at 5 and 10 years, respectively. Independent predictors of obliteration were no preradiosurgery embolization (p < 0.001), decreased AVM volume (p = 0.005), single draining vein (p = 0.013), lower radiosurgery-based AVM scale score (p = 0.016), and lower Virginia Radiosurgery AVM Scale (Virginia RAS) score (p = 0.001). The annual postradiosurgery hemorrhage rate was 1.4% with increased AVM volume (p = 0.034) and lower prescription dose (p = 0.006) as independent predictors. Symptomatic and permanent RICs were observed in 8.2% and 1.4% of patients, respectively. No preradiosurgery hemorrhage (p = 0.011), a decreased prescription dose (p = 0.038), and a higher Virginia RAS score (p = 0.001) were independently associated with postradiosurgery RICs. Spetzler-Martin Grade I and II AVMs are very amenable to successful treatment with stereotactic radiosurgery. While patient, physician, and institutional preferences frequently dictate the final course of treatment, radiosurgery offers a favorable risk-to-benefit profile for the management of low-grade AVMs.

Transarterial Embolization of Brain Arteriovenous Malformations

Background: Embolization is a safe curative tool in low-gradearteriovenous malformations (AVMs). N-butyl cyanoacrylate(NBCA) and Onyx are comparable to each other depending onthe lesion characteristics.Methods: Starting in 2003, 70 patients (31 males, 39 females;mean age, 29.7y; range, 7 to 72y) with intracranial AVMs wereembolized with NBCA and/or Onyx. Forty-four patients pre-sented with hemorrhage. AVMs were SM grade I in 4 patients,grade II in 21 patients, grade III in 32 patients, grade IV in 9patients, and grade V in 4 patients. AVMS were <3cm in 37patients.Findings: Angiographic cure was achieved in 35 patients (50%,35/70). NBCA was used in 45 AVMs, Onyx was used in 19AVMs, and both agents were used together in 6 AVMs. Per-manent neurological deficits occurred in 1 (1.43%) patient andtransient deficits in 7 (10%/patient, 6.73%/procedure). Hemo-rrhagic complications occurred in 7 patients (10% of patients,6.73% of procedures). Angiographic cure was 75% (3/4) ingrade I AVMs, 61.9% (13/21) in grade II, 43.75% (14/32) ingrade III, 44.44% (4/9) in grade IV, and 25% (1/4) in grade V.AVMs <3cm were cured in 72.97% of patients. There was noprocedure-related mortality. Follow-up for cured cases rangedfrom 6 months to 3 years.Conclusion: Low-grade AVMs can be embolized to cure usingOnyx and NBCA or in combination with high degree of safetyand efficacy. Both agents are similar in cure rate for small-sizedand medium-sized AVMs but with increased number of super-selective navigations and sessions in cases of NBCA with thepossibility of increased complications. Embolization is essentialfor management of high-grade AVMs as a part of the multi-modality approach.Key Words: arteriovenous malformations, Onyx, N-butyl cya-noacrylate (NBCA), superselective, embolization(Neurosurg Q 2013;00:000–000)

Analysis of X-knife and surgery in treatment of arteriovenous malformation of brain

The goal of treatment in arteriovenous malformation (AVM) is total obliteration of the AVM, restoration of normal cerebral function, and preservation of life and neurological function. To analyze the results of X-knife and surgery for AVM of the brain. The endpoints for success or failure were as follows: success was defined as angiographic obliteration and failure as residual lesion, requiring retreatment, or death due to hemorrhage from the AVM. From May 2002 to May 2007, 54 patients were enrolled for this study. Grade I AVM was seen in 9%, grade II in 43%, grade III in 26%, grade IV in 9%, and grade V in 13%. Thirty-eight patients were treated by microsurgical resection out of which Grade I was seen in 5 patients, Grade II was seen in 17 patients, Grade III was seen in 9 patients and Grade V was seen in 7 patients. Rest of the sixteen patients were treated by linear accelerator radiosurgery out of which Grade II was seen in 6 patients, Grade III was seen in 5 patients and Grade IV was seen in 5 patients. The follow up was in range of 3-63 months. In follow up, digital subtraction angiography/ magnetic resonance angiography (DSA/MRA) was performed 3 months after surgery and 1 year and 2 years after stereotactic radiosurgery (SRS). Among the patients treated with X-knife, 12/16 (75%) had proven angiographic obliteration. Complications were seen in 4/16 (25%) patients. Among the patients treated with microsurgical resection, 23/38 (61%) had proven angiographic obliteration. Complications (both intraoperative and postoperative) were seen in 19/38 (50%) patients. Sixty-one percent of patients were candidates for surgical resection. X-knife is a good modality of treatment for a low-grade AVM situated in eloquent areas of the brain and also for high-grade AVMs, when the surgical risk and morbidity is high.