Surgical management outcomes of intracranial arteriovenous malformations after preoperative embolization: a systematic review and meta-analysis

Curative Treatment of Brain Arteriovenous Malformations Combining Endovascular and Surgical Approaches Consecutively

BACKGROUND

Brain arteriovenous malformations (AVMs) pose a significant treatment challenge, with options including microsurgical resection, endovascular embolization, radiosurgery, or combinations thereof. We present our experience with a curative strategy combining complete endovascular treatment followed by microsurgical resection under the same anesthesia session, without relying on a hybrid operating room.

METHODS

We reviewed consecutive patients with AVM who underwent endovascular treatment and microsurgical resection in a single anesthesia session (COMBI-AVM protocol) from December 2017 to July 2022. Primary endpoints were angiographic AVM obliteration status and modified Rankin Scale score at last follow-up. AVMs were graded by the Spetzler-Martin (SM) system, comparing low-grade (SM I, SM II, SM III with nidus <3 cm) and high-grade (SM III with nidus ≥3 cm, SM IV, SM V) AVMs.

RESULTS

Of 46 patients with AVM, 34 had low-grade (73.9%) and 12 had high-grade (26.1%) AVMs. The protocol feasibility was 100%. Median anesthesia time was 8.7 hours (interquartile range, 7.6-10.6). Complete AVM removal was achieved in 45 patients (97.8%), with no recurrences at late (>6 months) follow-up in any of the 32 patients (71.1%) with available follow-up data. Good clinical outcomes (modified Rankin Scale score ≤2) were seen in 91.3% of patients. Disabling treatment-related complications occurred in 4 patients (8.6%), including 1 death (2.2%).

CONCLUSIONS

Combining maximal endovascular embolization and complete surgical resection in a single session in patients with AVM yielded a high cure rate and low morbidity, especially for low-grade lesions. This technique may make it possible to treat high-grade AVMs previously considered ineligible for surgery and reduce periprocedural morbidity.

Predictors of angiographic occlusion after embolization of intracranial arteriovenous malformations with curative intent

BackgroundEndovascular embolization is a potential alternative to open surgery for treating intracranial arteriovenous malformations (AVMs). To our knowledge, predictors of occlusion after curative embolization of AVMs remain limited in literature. Our study aims to identify predictors of radiographic occlusion after embolization of AVMs with curative intent.MethodsThis was a retrospective study of patients who underwent embolization of AVMs with curative intent at a single institution between 2007 and 2022. The primary outcome of cure was defined as radiographic occlusion of the AVM on follow-up. Univariate and multivariate analyses were performed with a P value <0.05 denoting statistical significance.ResultsSixty-six patients underwent embolization of an AVM with curative intent. The median (interquartile range (IQR)) age of the cohort was 53 (36-62), and 48.5% were male. 65.2% (n = 43) patients presented with hemorrhage. 59.1% (n = 39) of the cohort achieved cure on follow-up. Median (IQR) volume of AVM (mm3) and maximum pedicle size (mm) were significantly higher in patients who were not cured on follow-up compared to those who were cured: 14055.12 (2431.71-31235.60) and 1.9 (1.3-2.5) versus 3888 (2063-12518) and 1.3 (1.1-1.6), respectively. On multivariate regression, maximum pedicle size was associated with lower odds of cure (OR: 0.24, 95% CI: 0.07-0.82, P = 0.023).ConclusionsOur study identified maximum pedicle size to be the only significant factor associated with lower odds of radiographic occlusion after curative embolization of AVMs. Further multicenter studies are required to validate these findings.

Learning curve and embolisation strategy in single-stage surgery combined embolisation and microsurgery for brain arteriovenous malformations: results from a nationwide multicentre prospective registry study

OBJECTIVE

Single-stage surgery combining embolisation and microsurgery has been increasingly used as a stand-alone procedure to cure complex AVMs. This study aimed to investigate the learning curve and embolisation strategy for single-stage surgery for AVMs.

METHODS

This prospective cohort study used data from the nationwide Multimodality Treatment for Brain Arteriovenous Malformations (MATCH) registry in China, conducted between August 2011 and December 2023. A total of 213 complex AVMs were divided into two groups. Group 1 included the first 25 patients. The 188 cases in group 2 included patients numbered 26-213. A case-crossover design was employed to evaluate the influence of complications, unfavourable outcomes and worsening modified Rankin Scale (mRS) score. Cumulative summation analysis was performed to assess the learning curve.

RESULTS

The rate of major complications decreased from 52.00% in group 1 to 34.57% in group 2 (p=0.089), while the rate of unfavourable outcomes decreased from 44.00% in group 1 to 18.62% in group 2 (p=0.004). The distribution of the three preoperative embolisation strategies was as follows: curative: 72.00% and 19.15%, palliative: 24.00% and 67.55%, and targeted: 4.00% and 13.30%, respectively (p<0.001). Multivariable regression analysis showed that surgeon experience was associated with a lower rate of unfavourable outcomes (p=0.022, OR=0.333). The mean follow-up duration was 49.90±20.54 months. The follow-up mRS score of 5-6 decreased from 9.09% in group 1 to 0.8% in group 2 (p=0.035).

CONCLUSIONS

Performing single-stage combined surgery in 25 AVM cases is necessary to achieve reproducibility. Rates of major complications and unfavourable outcomes decreased significantly after the first 50 procedures. Palliative and targeted embolisation strategies are associated with a lower rate of unfavourable outcomes.

TRIAL REGISTRATION NUMBER

NCT04572568.

Advanced targeted microsphere embolization for arteriovenous malformations: state-of-the-art and future directions

BACKGROUND

Arteriovenous malformations (AVMs) present a significant therapeutic challenge, as current treatment modalities frequently fail to achieve complete and rapid obliteration and are associated with substantial morbidity in both the short and long term. This underscores the critical need for innovative therapeutic strategies that enable efficient AVM obliteration while minimizing patient risk. The current review aims to comprehensively assess the role of ATME in AVM management, examining its clinical efficacy, associated risks and benefits, and the economic and ethical implications to provide valuable foundation for future studies and guiding development in treatment strategies for AVMs.

RESULTS

Advanced targeted microsphere embolization (ATME) has emerged as a promising therapeutic option, initially developed for the localized treatment of AVMs and unresectable tumors, including liver cancer. By providing targeted delivery, ATME offers potential advantages over conventional approaches in achieving effective local control.

CONCLUSIONS

ATME are safe and effective for vascular disease and cancer. Although evidence for microspheres in AVMs is scarce, results are promising. Future research could refine eligibility criteria, evaluate treatment techniques, and optimize ATME.

Long-term outcomes and prognostic factors after surgery alone for brain arteriovenous malformation

OBJECTIVES

There is a paucity of data regarding the long-term hemorrhage/progression outcomes of brain arteriovenous malformation (BAVM). The purpose of this study was to examine the outcomes of surgical treatment alone over a long follow-up period.

MATERIALS AND METHODS

All patients (n = 356) harboring Grade I-III BAVMs who had been surgically treated alone between January 2010 and December 2019 were included. Univariate analysis and multivariate analysis with proportional hazard models were implemented to identify the predictors of hemorrhage-free survival (HFS) (n = 356) and progression-free survival (PFS) (n = 334).

RESULTS

Of the 356 BAVM patients, 233 were male and 123 were female (male-to-female ratio of 1.89:1). Rehemorrhage was observed in 22 (6.2%) patients. The overall HFS rates at 5, 10, and 15 years in the entire cohort were 96.0%, 92.4%, and 91.1%, respectively. A 1 cm3 increase in lesion volume (hazard ratio [HR] = 1.049, 95% confidence interval [CI] = 1.013-1.085; P = 0.007) was a significant adverse factor for HFS. The probabilities of PFS at 5, 10, and 15 years were 94.9%, 90.6%, and 85.5%, respectively. With respect to clinical predictors of PFS, only male sex (HR = 3.146, 95% CI = 1.088-9.098; P = 0.034) was a significant predictor of PFS after surgical treatment in the univariate analysis.

CONCLUSIONS

For the majority of patients, surgery remains the first-line treatment for BAVMs. Our study included a significant subset of patients who were successfully managed by surgery alone.

Challenging Management of a Rare Complex Cerebral Arteriovenous Malformation in the Corpus Callosum and Post-Central Gyrus: A Case Study of a 41-Year-Old Female

Background/Objectives: Cerebral arteriovenous malformations (AVMs) are rare but complex vascular anomalies, particularly challenging when located in eloquent regions such as the corpus callosum and post-central gyrus. This report aims to highlight the management and outcomes of a 41-year-old female patient with a hemorrhagic AVM in these critical areas, emphasizing the importance of early surgical intervention and advanced imaging techniques. Methods: The patient presented with a right-sided tonic-clonic seizure and expressive aphasia, prompting imaging that revealed a complex AVM with deep venous drainage and arterial supply from the anterior cerebral artery. A multidisciplinary team performed microsurgical resection via a left parasagittal fronto-parietal craniotomy. The surgical approach prioritized hematoma evacuation followed by a stepwise dissection of the AVM nidus under intraoperative monitoring. Results: Complete resection of the AVM was confirmed through postoperative angiographic and CT imaging. The patient showed stable recovery over 15 months, with no recurrence or new neurological deficits. This case demonstrates the critical role of advanced imaging, intraoperative strategies, and a multidisciplinary approach in achieving successful outcomes. Conclusions: Microsurgical resection remains the gold standard for AVMs in eloquent and deep-seated brain regions. Early diagnosis and tailored surgical interventions are crucial for managing these high-risk cases. This case underscores the importance of integrating advanced imaging, strategic surgical planning, and intraoperative monitoring to minimize complications and optimize long-term recovery.

Comparison of Repeat Versus Initial Stereotactic Radiosurgery for Intracranial Arteriovenous Malformations: A Retrospective Multicenter Matched Cohort Study

BACKGROUND AND OBJECTIVES

Studies comparing neurological and radiographic outcomes of repeat to initial stereotactic radiosurgery (SRS) intracranial arteriovenous malformations are scarce. Our aim was to perform a retrospective matched comparison of patients initially treated with SRS with those undergoing a second radiosurgical procedure.

METHODS

We collected data from arteriovenous malformations managed in 21 centers that underwent initial and repeated radiosurgery from 1987 to 2022. Based on arteriovenous malformations volume, margin dose, deep venous drainage, deep, and critical location, we matched 1:1 patients who underwent an initial SRS for treatment-naive arteriovenous malformations and a group with repeated SRS treatment.

RESULTS

After the selection process, our sample consisted of 328 patients in each group. Obliteration in the initial SRs group was 35.8% at 3 and 56.7% at 5 years post-SRS, while the repeat SRS group showed obliteration rates of 33.9% at 3 years and 58.6% at 5 years, without statistically significant differences (P = .75 and P = .88, respectively). There were no statistically significant differences between the 2 groups for obliteration rates (hazard ratio = 0.93; 95% CI, 0.77-1.13; P = .5), overall radiation-induced changes (RIC) (OR = 1.1; 95% CI, 0.75-1.6; P = .6), symptomatic RIC (OR = 0.78; 95% CI, 0.4-1.5; P = .4), and post-SRS hemorrhage (OR = 0.68; 95% CI; P = .3).

CONCLUSION

In matched cohort analysis, a second SRS provides comparable outcomes in obliteration and RIC compared with the initial SRS. Dose reduction on repeat SRS may not be warranted.

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.

Influence of preoperative embolisation on resection of brain arteriovenous malformations: cohort study

PURPOSE

Preoperative endovascular embolisation is a widely used adjunct for the surgical treatment of brain arteriovenous malformations (AVMs). However, whether this improves completeness of AVM resection is unknown, as previous analyses have not adjusted for potential confounding factors. We aimed to determine if preoperative endovascular embolisation was associated with increased rate of complete AVM resection at first surgery, following adjustment for Spetzler-Martin grade items.

METHODS

We identified a cohort of all patients undergoing first ever AVM resection in a specialist neurosciences unit in the NHS Lothian Health Board region of Scotland between June 2004 and June 2022. Data was prospectively extracted from medical records. Our primary outcome was completeness of AVM resection. We determined the odds of complete AVM resection using binomial logistic regression with adjustment for Spetzler-Martin grading system items: maximum nidus diameter, eloquence of adjacent brain and the presence of deep venous drainage.

RESULTS

88 patients (median age 40y [IQR 19-53], 55% male) underwent AVM resection. 34/88 (39%) patients underwent preoperative embolisation and complete resection was achieved at first surgery in 74/88 (84%). Preoperative embolisation was associated with increased adjusted odds of complete AVM resection (adjusted odds ratio [aOR] 8.6 [95% confidence interval (95% CI) 1.7-67.7]; p = 0.017). The presence of deep venous drainage was associated with reduced chance of complete AVM resection (aOR 0.18 [95% CI 0.04-0.63]; p = 0.009).

CONCLUSIONS

Preoperative embolisation is associated with improved chances of complete AVM resection following adjustment for Spetzler-Martin grade, and should therefore be considered when planning surgical resection of AVMs.

Clinical analysis of surgical outcome of 89 patients having large cerebral arteriovenous malformations

OBJECTIVE

The article analyzes the clinical features, morphological characteristics, surgical subtleties and long-term outcome of surgery in 89 cases of 'large' sized AVMs.

MATERIALS AND METHODS

During the period 2004 to 2022, 89 cases of 'large' arteriovenous malformations were operated in the neurosurgery departments of the authors. Large AVMs were defined as those that were more than 4 cm on either lateral or antero-posterior view of digital subtraction angiogram. The factors that determined the extent of surgical difficulties included site and eloquence of the area, number of feeding vascular territories and draining veins, degree and rate of flow, presence of flow-related aneurysms, and the physical nature of the arteriovenous malformation.

RESULTS

There were 59 males and 30 females and the average age was 32 years. Headache, giddiness and convulsions were the common presenting complaints. Six patients were unconscious after surgery. Of these, five patients died in the immediate post-operative period and one patient gradually recovered. Additionally, seven patients developed unilateral limb weakness that included hemiplegia (4 patients) and hemiparesis (3 patients) following surgery. Clinical follow-up ranged from 6 months to 18 years (average 43 months). All surviving patients are leading normal and essentially symptom free life and have recovered from their symptoms of headache, convulsions and giddiness.

CONCLUSIONS

Large AVMs are amenable to 'curative' surgery with 'acceptable' results. The surgery can be challenging and appropriate case selection that is based on the surgeons experience is vital and decisive.

Most Promising Approaches to Improve Brain AVM Management: ARISE I Consensus Recommendations

Brain arteriovenous malformations (bAVMs) are complex, and rare arteriovenous shunts that present with a wide range of signs and symptoms, with intracerebral hemorrhage being the most severe. Despite prior societal position statements, there is no consensus on the management of these lesions. ARISE (Aneurysm/bAVM/cSDH Roundtable Discussion With Industry and Stroke Experts) was convened to discuss evidence-based approaches and enhance our understanding of these complex lesions. ARISE identified the need to develop scales to predict the risk of rupture of bAVMs, and the use of common data elements to perform prospective registries and clinical studies. Additionally, the group underscored the need for comprehensive patient management with specialized centers with expertise in cranial and spinal microsurgery, neurological endovascular surgery, and stereotactic radiosurgery. The collection of prospective multicenter data and gross specimens was deemed essential for improving bAVM characterization, genetic evaluation, and phenotyping. Finally, bAVMs should be managed within a multidisciplinary framework, with clinical studies and research conducted collaboratively across multiple centers, harnessing the collective expertise and centralization of resources.

Deliberately Staged Combined Endovascular Embolization and Subsequent Microsurgery Resection for the Treatment of Cerebral Arteriovenous Malformations

OBJECTIVE

Complex cerebral arteriovenous malformations (AVMs) require a combined therapy of endovascular embolization and microsurgical resection to eliminate the lesion and maximize neurological protection, while a deliberate time interval might contribute to optimal clinical outcomes. The present study aimed to explore the feasibility of this paradigm.

METHODS

All patients who underwent deliberately planned presurgery embolization and microsurgery resection between 2015 and 2023 were reviewed, with baseline data, postoperative complications, and follow-up outcomes recorded. The modified Rankin scale (mRS) was used to evaluate clinical outcomes, with mRS 0-2 defined as good.

RESULTS

A total of 30 patients were included in the study (15 were ruptured AVMs). The median Spetzler-Martin grade of baseline AVMs was 3 (interquartile range: 2-3). The median interval between the last embolization and microsurgery was 5 days (interquartile range: 2.25-7). The complete removal rate was 100%, and the overall permanent complication rate was 16.67%. At the last follow-up, 26 patients achieved mRS 0-2, while 28 had improved or unaltered mRS. The last follow-up mRS significantly improved from baseline and discharge (P = 0.0006 and P = 0.006). The last follow-up mRS decreased by 0.65 for each additional day of time interval before the 4.4-day inflection point (β = -0.65, P = 0.02) in the AVM ruptured cohort.

CONCLUSIONS

The deliberately staged combined procedure of embolization and microsurgery might be a safe and efficacious strategy for Spetzler-Martin grade 2-5 AVMs, 4-5 days might be an appropriate staged time interval for ruptured AVMs, although further studies are needed to substantiate these findings.

Multi-Stage Treatment for Spetzler-Martin Grades III, IV, and V Arteriovenous Malformations: Preoperative Embolization and Microsurgical Resection in a Consecutive Series of 250 Patients

PURPOSE

The treatment of high-grade brain AVMs is challenging and has no guidelines available to date. This study was aimed at reporting the experience of two centers in treating these AVMs through a multi-stage approach consisting of preoperative embolization and microsurgical resection.

METHODS

A retrospective review was performed for 250 consecutive patients with a diagnosis of high-grade brain AVM (Spetzler-Martin grades III, IV, and V) treated in two centers in Germany between January 1989 and February 2023. The analyzed data included demographic, clinical, morphological, and neurological data.

RESULTS

A total of 150 cases (60%) were classified as Spetzler-Martin grade III, 82 cases (32.8%) were classified as grade IV, and 18 cases (7.2%) were classified as grade V. Eighty-seven cases (34.8%) presented with hemorrhage. The devascularization percentages achieved were <50% in 24 (9.6%), 50-80% in 55 (22%), and >80% in 171 (68.4%) cases. The average number of sessions was 5.65 ± 5.50 and 1.11 ± 0.32 endovascular and surgical procedures, respectively, and did not significantly differ by rupture status. Death or dependency (mRS score ≥ 3) after the last follow-up was observed in 18.8% of patients and was significantly associated with age > 80 years and poor baseline neurological condition. The complete resection rate was 82.3% and was significantly associated with age > 80 years, large nidus, and deep venous drainage. Permanent disabling neurological deficit after at least 3 months of follow-up was diagnosed in 13.2% of patients and was significantly associated with age > 80 years and infratentorial locations.

CONCLUSION

A multi-stage treatment for high-grade AVMs is feasible for selected cases but comes at a functional cost. The devascularization percentage was not associated with the investigated outcomes. Age > 80 years was associated with poor safety and effectiveness outcomes; consequently, this treatment should be offered only in exceptional circumstances.

Intracranial arteriovenous malformation (AVM) or meningothelial meningioma (MM)? Outlining the similarities and differences on imaging studies for an accurate diagnosis, case report

INTRODUCTION AND IMPORTANCE

AVM and MM represent neurosurgical challenges, not only when involving eloquent brain, but also by posing a significant intraoperative haemorrhagic risk. It is a challenge in itself to establish a proper differential diagnosis between the two lesions, especially since they require distinct interventional plan of action. We present the case of a patient initially diagnosed by specialists with an intracranial AVM, which was revealed intraoperatively to be in fact an MM.

CASE PRESENTATION

A 29-years patient, transferred to our department by urgency. The patient symptoms started two weeks prior admission with severe headache and vomiting. A cerebral computer tomographic angiography (CTA) was performed and interpreted by radiologists, as a large left frontal AVM.

CLINICAL DISCUSSION

Upon through review the majority of surgical team believed the mass to be AVM. However, during surgery it turned out to be Meningioma. The patient underwent a left pterional craniotomy with removal of the tumour, classified as Simpson grade II. The pathological exam confirmed the lesion to be an MM.

CONCLUSIONS

Acquiring neuro-radiological expertise is vital for the neurosurgeon, as well as fast ability for adjusting the initial action plan with the intraoperative discoveries. An experienced eye can benefit the patient by obtain a correct diagnosis in most difficult cases.