Impact of Pre-operative Embolization With Onyx for Brain Arteriovenous Malformation Surgery

Microsurgery alone versus preoperative embolisation: A meta-analysis of outcomes in brain AVMs by Spetzler-Martin grade

Preoperative embolisation is frequently used an adjunct to microsurgery for brain arteriovenous malformations (AVMs), yet high-level evidence supporting its routine use remains limited. This meta-analysis compares outcomes of microsurgery alone versus combined microsurgery and preoperative embolisation, stratified by Spetzler-Martin (SM) grade. A systematic review of Embase, Medline, Scopus, Emcare, and the Cochrane Library identified 43 studies encompassing 3916 patients, equally divided between microsurgery alone (n = 1958) and combination therapy (n = 1958). Primary endpoints included functional dependence (modified Rankin Scale score > 2), angiographic obliteration, haemorrhagic complications, and intraoperative blood loss. Pooled analyses demonstrated no significant differences in functional dependence (OR 0.65, 95 % CI 0.32-1.32, p = 0.21), obliteration rates (OR 1.15, 95 % CI 0.60-2.19, p = 0.63), haemorrhagic complications (OR 1.67, 95 % CI 0.71-3.95, p = 0.20), or intraoperative blood loss (MD -98.90 mL, 95 % CI -417.38-219.57, p = 0.44). Subgroup analysis for SM grade I-II and III-V AVMs found no significant differences in outcomes between treatment modalities. For SM grade III AVMs, angiographic cure rates were comparable, though data scarcity precluded a robust assessment of functional dependence, postoperative haemorrhage, and intraoperative blood loss. While theoretical advantages exist for preoperative embolisation in higher-grade or high-flow AVMs, current evidence does not demonstrate consistent benefits in outcomes or complication rates. Further studies, particularly for SM grade III AVMs, are needed to determine whether combination therapy provides a meaningful advantage over microsurgery alone.

Microsurgical resection and endovascular embolization of a left inferior frontal and Sylvian Spetzler-Martin grade 3 arteriovenous malformation

Background

Arteriovenous malformations (AVMs) carry an estimated 2-4% annual risk of rupture, with an estimated 70-75% lifetime risk. They are typically discovered during young adulthood, occurring in approximately 5/10,000 individuals. Modalities of treatment involve endovascular treatment, Gamma Knife, microsurgical resection under general anesthesia, awake craniotomy, or a combination of these modalities.

Case Description

We present the case of a 33-year-old male presenting with headaches who was found to have an incidental left inferior frontal Spetzler-Martin Grade 3 AVM adjacent to Broca's area. Given the large size of the AVM, the patient's young age, and the lifetime risk of rupture, the patient underwent a planned 2-stage preoperative embolization and microsurgical resection under general anesthesia with intraoperative monitoring. Complete resection of the AVM was observed on postoperative digital subtraction angiography. The patient was discharged home on postoperative day 4. The patient's transient postoperative mixed aphasia had fully resolved by the time of discharge. A review of the benefits of preoperative embolization and the technical considerations of resection of a large AVM in eloquent regions of the brain are included. The patient consented to the procedure and the publication of his images. The Institutional Review Board approval was deemed unnecessary due to the retrospective, case-report nature of this work.

Conclusion

Large AVMs in the eloquent brain can present a challenge to the surgeon. Staged, multi-modality intervention involving staged preoperative embolization and functional MRI preoperative planning can be an effective treatment strategy for strategic, safe microsurgical resection under general anesthesia for AVMs in the eloquent brain.

Chronological Changes in Embolization for Cerebral Arteriovenous Malformations: Impact of Endovascular Treatment Device Advancements

Objective

Although embolization of cerebral arteriovenous malformations (AVM) is widely performed as an adjunctive therapy before microsurgery or radiosurgery, there is no high-level evidence to ascertain its effectiveness. However, the technology for endovascular devices has improved. Therefore, this study aimed to identify the chronological changes in AVM embolization due to advances in endovascular treatment devices.

Methods

This retrospective study included 24 patients who underwent 31 embolization procedures between January 2018 and August 2023. Embolization plus microsurgery, embolization plus radiosurgery, and embolization alone were performed in 15 (62.5%) patients and 21 embolization procedures, 2 (8.3%) patients and 2 procedures, and 7 (29.2%) patients and 8 procedures, respectively. We assessed chronological changes in endovascular treatment devices and evaluated clinical outcomes (ideal position of microcatheter, vessel perforations, symptomatic complications) from January 2018 to December 2020 and from January 2021 to August 2023 based on the chronological changes in endovascular treatment devices.

Results

Intermediate catheters were employed in 29 (93.5%) procedures. Brands of intermediate catheters and microcatheters significantly changed around 2021. No differences were observed in the embolic materials. The ideal position of the microcatheter was achieved significantly more in 2021-2023 than in 2018-2020 (72.1% vs. 48.4%, p = 0.04). Vessel perforation by microcatheters in 2018-2020 and 2021-2023 occurred in 3 (18.8%) and 1 (6.7%) procedures (p = 0.32), respectively. Symptomatic complications in 2018-2020 and 2021-2023 occurred in 3 (18.8%) and 0 (p = 0.08) procedures, respectively. Complete obliteration was achieved in 18 of 24 patients (75.0%). Favorable clinical outcomes (modified Rankin Scale score 0-2) were observed in 20 of 24 (83.3%) patients at the final follow-up.

Conclusion

The advancement in endovascular devices for AVM has enabled effective and safe embolization, potentially enhancing the outcomes of microsurgical interventions.

Early versus Delayed Surgical Management of Ruptured Arteriovenous Brain Malformations in a Tertiary Referral Center in Colombia, South America

BACKGROUND

Surgical timing after rupture of brain arteriovenous malformations (AVMs) is controversial. There is scarce literature on AVM surgical outcomes from developing countries. This study aims to determine if there is a difference between early and delayed surgical resection for patients with ruptured brain AVMs.

METHODS

This single-center retrospective review included patients who underwent surgical resection for ruptured brain AVMs in Colombia. Patients were stratified by the timing of surgical intervention relative to the rupture into early (≤72 hours of bleeding) and delayed (>72 hours) resection. Continuous variables were analyzed using an independent t-test, and dichotomous variables were analyzed using a χ2 test. A linear regression analysis was performed with the final mRankin score at 2 years as the dependent variable; P < 0.05 was considered significant.

RESULTS

Thirty-one patients were identified. The early treatment group included 14 (45.2%) patients, and the delayed group included 17 (54.8%) patients. The mean (SD) length of time between AVM rupture and surgical resection was 1.6 ± 1.2 days and 12.4 ± 8.4 days, respectively (P < 0.001). There were no differences regarding demographics, perioperative variables, and postoperative outcomes between groups. In the linear regression analysis, the only variable that had a significant association with the final mRankin score was the initial Glasgow Coma Scale, which had a β coefficient of -0.6341 (95% confidence interval: -0.41,-0.017, P = 0.035).

CONCLUSIONS

In this case series of 31 patients from a developing country, there were no differences in clinical outcomes at the final follow-up between acute and delayed surgical interventions for ruptured AVMs. The most important factor associated with the final outcomes was the initial Glasgow Coma Scale.

Comparison of conservative management, microsurgery only, and microsurgery with preoperative embolization for unruptured arteriovenous malformations: A propensity score weighted prospective cohort study

AIMS

To compare the efficacy and deficiency of conservative management (CM), microsurgery (MS) only, and microsurgery with preoperative embolization (E + MS) for unruptured arteriovenous malformations (AVMs).

METHODS

We prospectively included unruptured AVMs undergoing CM, MS, and E + MS from our institution between August 2011 and August 2021. The primary outcomes were long-term neurofunctional outcomes and hemorrhagic stroke and death. In addition to the comparisons among CM, MS, and E + MS, E + MS was divided into single-staged hybrid and multi-staged E + MS for further analysis. Stabilized inverse probability of treatment weighting using propensity scores was applied to control for confounders by treatment indication across the three groups.

RESULTS

Of 3758 consecutive AVMs admitted, 718 patients were included finally (266 CM, 364 MS, and 88 E + MS). The median follow-up duration was 5.4 years. Compared with CM, interventions (MS and E + MS) were associated with neurological deterioration. MS could lower the risk of hemorrhagic stroke and death. Multi-staged E + MS was associated with neurological deterioration and higher hemorrhagic risks compared with MS, but the hybrid E + MS operation significantly reduced the hemorrhage risk.

CONCLUSION

In this study, unruptured AVMs receiving CM would expect better neurofunctional outcomes but bear higher risks of hemorrhage than MS or E + MS. The single-staged hybrid E + MS might be promising in reducing inter-procedural and subsequent hemorrhage.

Impact of tailored multimodal treatment for unruptured brain arteriovenous malformation: comparison with a randomized trial of unruptured brain arteriovenous malformations

PURPOSE

The first randomized controlled study on unruptured brain arteriovenous malformations (bAVM), the ARUBA trial, demonstrate the superiority of medical management; however, it failed to completely rule out the efficacy of therapeutic interventions due to several limitations. This study aimed to examine the outcomes of multimodal interventional treatment for bAVM in terms of safety and efficacy.

METHODS

We reviewed 226 consecutive patients with unruptured bAVM admitted to our institute between 2002 and 2022. Treatment methods were divided into medical management and therapeutic intervention, including microsurgery, stereotactic surgery, and endovascular intervention. First, the choice of therapeutic modalities was assessed in the pre-ARUBA (before February 2014) and post-ARUBA (after March 2014) eras. Second, the incidence of symptomatic stroke or death and functional prognosis with a modified Rankin scale (mRS) score of ≥2 at 5 years was compared between the medical management and therapeutic intervention.

RESULTS

In the pre- and post-ARUBA groups, 73% and 84% of patients underwent therapeutic interventions, respectively (p = 0.053). The rate of symptomatic stroke or death was lower in patients who underwent interventional therapies than in those who underwent medical management (9.7% vs. 22%, p = 0.022); however, the opposite was observed in the ARUBA trial (31% vs. 10%). The annual incidence of stroke or death was also lower in the interventional therapy group (4.3%/y vs. 1.8%/year, hazard ratio = 0.45, 95% confidence interval: 0.18-1.08, p = 0.032). The rate of mRS score of ≥2 after a 5-year follow-up was 18% and 6% in the medical treatment and intervention groups (p = 0.14).

CONCLUSIONS

The therapeutic intervention rate did not decrease, even after the publication of the ARUBA trial. The rate of stroke or death was lower in the intervention group, indicating that a tailored choice of multimodality is safe and effective for managing unruptured bAVM.

An overview of interventional radiology techniques for the diagnosis and management of vascular anomalies: Part 2

Minimally invasive percutaneous and endovascular strategies performed by interventional radiologists have become the mainstays of treatment for vascular anomalies with improved outcomes, decreased complication rates, and less morbidity. The aim of this article is to introduce physicians who care for patients with vascular anomalies to state-of-the-art advancements in interventional radiology for diagnosis and treatment. Part 2 of this review discusses embolization, endovenous laser ablation, and image-guided percutaneous biopsy. Please see Part 1 for a discussion of sclerotherapy and cryoablation. Select vascular anomalies will be discussed as examples to highlight IR diagnostic and/or treatment techniques.

Imaging Characteristics of Tongue Hematoma and Pseudoaneurysm Following Tooth Extraction Requiring Emergency Liquid Embolization

Our case describes the imaging characteristics of a tongue hematoma and lingual artery pseudoaneurysm following oral surgery, treated with a liquid embolic agent prior to repeat instrumentation. Identifying particular imaging cues that suggest underlying vascular pathology is essential to prevent unnecessary, potentially fatal instrumentation. A liquid embolizing agent can be used to endovascularly treat an unstable pseudoaneurysm in the oral cavity.

Comparative outcome of endovascular embolization with microsurgery in managing acute spontaneous cerebral hemorrhage in pediatric patients, an institutional experience

OBJECTIVES

A few previous studies have reported the role of embolization with curative intent in the treatment of the early phase of a spontaneous cerebral hemorrhage in pediatric patients, and its efficacy needs to be compared with surgery at the same time risk factors for hemorrhage following early embolization in such patients need to be evaluated.

METHODS

From a pool of 80 pediatric (< 18 years) who had undergone treatment for ruptured AVM with hemorrhage at our center between July 2018 and July 2022, we identified 36 patients with spontaneous bleeding due to AVM. Out of which, 20 were treated solely by embolization (group 1), while the remaining patients were treated surgically (with and without adjuvant embolization) (group 2).

RESULT

Spetzler-Martin's grading of the lesion suggested seven lesions < 3 and 13 lesions ≥ 3 in the embolization group. Similarly, seven lesions were < 3 and nine ≥ 3 Spetzler-Martin grade in the surgery group. Incomplete embolization was associated with hemorrhage in two patients treated with curative intent and four patients treated with embolization as adjuvant in the surgery group (p = 0.01). On follow-up, 18 patients in the embolization group and 12 in the surgery group had Glasgow outcome scores ≥ 4 (p = 0.273).

CONCLUSION

In the pediatric age group, incomplete embolization is the significant risk factor for hemorrhage in AVMs treated after a hemorrhagic stroke. Embolization with curative intent is as effective as surgery in treating such lesions as adjuvant embolization with careful patient selection.

Intra- and post-operative acute hemorrhagic complications of Onyx embolization of brain arteriovenous malformations: A single-center experience

Background

The intra- and post-operative acute (within 72 h) hemorrhagic complications of endovascular treatment (EVT) for a brain arteriovenous malformation (BAVM) are disastrous. Thus, further experiential summaries are required to fully understand them.

Materials and methods

This was a retrospective study of 25 patients with consecutive BAVM who were treated via EVT with Onyx embolization and suffered intra- and post-operative acute hemorrhage. The clinical and imaging data of the patients were recorded, analyzed, and discussed.

Result

Twenty-five patients were aged 11-70 years (mean, 37.2 ± 16.1 years), of whom 12 were female (48%, 12/25). Of the 25 hemorrhagic complications, 17 (68%, 17/25) were intraoperative, and 8 (32%, 8/25) were post-operative and occurred between 1 and 12 h after EVT. Of 17 intraoperative hemorrhages, 13 (76.5%, 13/17) were due to high-pressure Onyx casting. Of eight post-operative hemorrhages, six (75%, 6/8) were attributed to normal perfusion pressure breakthrough. The degree of nidus Onyx embolization was more than 2/3 or complete in seven (87.5%, 7/8) BAVMs. Draining vein occlusion was observed in eight (32%, 8/25) of 25 BAVMs. After hemorrhage, conservative treatment was administered in 12 (48%, 12/25) cases, and surgical management was performed in other cases. There were eight cases of mortality; the remaining 17 patients had follow-up data. Among them, 15 patients had good outcomes, with Glasgow Outcome Scale scores of 5 and 4, accounting for 60% (15/25).

Conclusion

In EVT for BAVMs, intra- and post-operative acute hemorrhagic complications are disastrous; only 60% of patients have a good outcome. Therefore, high-pressure Onyx casting or casting too much Onyx at one time to pursue a high degree of nidus embolization should be performed cautiously, and primary draining vein occlusion should be avoided. In short, EVT needs to be performed carefully.