Combined staged therapy of complex arteriovenous malformations: initial experience

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.

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

Objective

To clarify the safety and efficacy of pre-operative embolization using Onyx liquid embolic agent (Onyx; ev3) compared with N-butyl cyanoacrylate (NBCA; Cordis Neurovascular, Inc.) or coils in cerebral arteriovenous malformation (AVM) surgery.

Methods

This was a retrospective review of a prospectively collected clinical database of brain AVMs treated at our institute from January 2005 to March 2021. A total of 38 consecutive patients who underwent AVM resection after pre-operative embolization were included. Based on pre-operative embolization materials, the patients were divided into the pre-Onyx group (n = 16), in which NBCA or coils were used for embolization, and the Onyx group (n = 22). Patient characteristics and treatment results were compared between the two groups.

Results

Patient characteristics were comparable between the two groups in terms of age, sex, and rupture status. While the Spetzler-Martin grade was also similar between the two groups, the location of the AVM nidus in the eloquent area was slightly higher in patients in the Onyx group (72.7%) than in patients in the pre-Onyx group (43.8%) (P = 0.09). The embolization rate was higher in the pre-Onyx group (mean: 63.0%; range: 12.7-100%) than in the Onyx group (mean: 50.0%; range: 15.8-100%), but the difference was not statistically significant (P = 0.06). The time needed for surgical removal was shorter in the Onyx group (mean: 354.8 min; range: 144-884 min) than in the pre-Onyx group (mean: 457.9 min; range: 240-1,294 min); however, this difference was not statistically significant (P = 0.13). The amount of intraoperative bleeding was significantly lower in the Onyx group (mean: 129.8 ml; range: 20-540 mL) than in the pre-Onyx group (mean: 448.8 mL; range: 120-1,550 ml) (P = 0.0008). The surgical complication rates were comparable between the two groups (pre-Onyx group, 18.8%; Onyx group, 4.5%; P = 0.29).

Conclusions

Pre-operative embolization with Onyx can significantly reduce the amount of intraoperative bleeding in AVM resection and may contribute to safe AVM surgery.

Multimodality Treatment of Brain Arteriovenous Malformations with One-Staged Hybrid Operation: Clinical Characteristics and Long-Term Prognosis

Objective

We aimed to evaluate the clinical characteristics and long-term prognosis of brain arteriovenous malformations (bAVMs) treated with multimodality management of one-staged hybrid operation.

Methods

We identified bAVM patients treated with one-staged hybrid operation from a multicenter prospective cohort study (NCT03774017) between January 2016 and June 2020. Patients were divided into unruptured and ruptured groups by the hemorrhagic presentation. Long-term (>12 months) neurological disability, postoperative complications of stroke, and nidus obliteration were evaluated and compared between groups. Prognostic predictors associated with outcomes were analyzed.

Results

A total of 130 patients were identified in the study receiving one-staged hybrid operations, including 61 unruptured cases and 69 ruptured cases. Mean age was 29.1 years old, with 78 (60.0%) being male. Patients included in the study were followed up for a mean period of 37.4 (11.07) months. The annual hemorrhagic risk was 4.2% per year. Thirteen postoperative stroke events were detected in 11 patients (8.5%). Long-term disability occurred in 6.9% of cases, and 86.2% of patients experienced an unchanged or improved neurological status at the last follow-up. All patients achieved complete obliteration on follow-up angiographies. Increased AVM volume was associated with a higher risk of postoperative stroke (odds ratio (OR) 1.021, 95% confidence interval (CI) 1.006-1.037, and P = 0.006). Poor neurological status (OR 6.461, 95% CI 1.309-31.889, and P = 0.022) and infratentorial location (OR 5.618, 95% CI 1.158-27.246, and P = 0.032) were independent predictors for long-term disability.

Conclusions

One-staged hybrid operation of embolization combined microsurgical resection can be performed as a safe and effective strategy for bAVM treatments. Long-term prognosis of complete obliteration with low rates of morbidity and mortality can be achieved. Unruptured and ruptured bAVMs acquired similar favorable outcomes after the multimodality treatment.

Chinese Cerebrovascular Neurosurgery Society and Chinese Interventional & Hybrid Operation Society, of Chinese Stroke Association Clinical Practice Guidelines for Management of Brain Arteriovenous Malformations in Eloquent Areas

Aim: The aim of this guideline is to present current and comprehensive recommendations for the management of brain arteriovenous malformations (bAVMs) located in eloquent areas. Methods: An extended literature search on MEDLINE was performed between Jan 1970 and May 2020. Eloquence-related literature was further screened and interpreted in different subcategories of this guideline. The writing group discussed narrative text and recommendations through group meetings and online video conferences. Recommendations followed the Applying Classification of Recommendations and Level of Evidence proposed by the American Heart Association/American Stroke Association. Prerelease review of the draft guideline was performed by four expert peer reviewers and by the members of Chinese Stroke Association. Results: In total, 809 out of 2,493 publications were identified to be related to eloquent structure or neurological functions of bAVMs. Three-hundred and forty-one publications were comprehensively interpreted and cited by this guideline. Evidence-based guidelines were presented for the clinical evaluation and treatment of bAVMs with eloquence involved. Topics focused on neuroanatomy of activated eloquent structure, functional neuroimaging, neurological assessment, indication, and recommendations of different therapeutic managements. Fifty-nine recommendations were summarized, including 20 in Class I, 30 in Class IIa, 9 in Class IIb, and 2 in Class III. Conclusions: The management of eloquent bAVMs remains challenging. With the evolutionary understanding of eloquent areas, the guideline highlights the assessment of eloquent bAVMs, and a strategy for decision-making in the management of eloquent bAVMs.

Periprocedural intracranial hemorrhage after embolization of cerebral arteriovenous malformations: a meta-analysis

OBJECTIVE

The primary goal of the treatment of cerebral arteriovenous malformations (AVMs) is angiographic occlusion to eliminate future hemorrhage risk. Although multimodal treatment is increasingly used for AVMs, periprocedural hemorrhage after transarterial embolization is a potential endovascular complication that is only partially understood and merits quantification.

METHODS

Searching the period between 1990 and 2019, the authors of this meta-analysis queried the PubMed and Embase databases for studies reporting periprocedural hemorrhage (within 30 days) after liquid embolization (using cyanoacrylate or ethylene vinyl alcohol copolymer) of AVMs. Random effects meta-analysis was used to evaluate the pooled rate of flow-related hemorrhage (those attributed to alterations in AVM dynamics), technical hemorrhage (those related to procedural complications), and total hemorrhage. Meta-regression was used to analyze the study-level predictors of hemorrhage, including patient age, Spetzler-Martin grade, hemorrhagic presentation, embolysate used, intent of treatment (adjuvant vs curative), associated aneurysms, endovascular angiographic obliteration, year of study publication, and years the procedures were performed.

RESULTS

A total of 98 studies with 8009 patients were included in this analysis, and the mean number of embolization sessions per patient was 1.9. The pooled flow-related and total periprocedural hemorrhage rates were 2.0% (95% CI 1.5%-2.4%) and 2.6% (95% CI 2.1%-3.0%) per procedure and 3.4% (95% CI 2.6%-4.2%) and 4.8% (95% CI 4.0%-5.6%) per patient, respectively. The mortality and morbidity rates associated with hemorrhage were 14.6% and 45.1%, respectively. Subgroup analyses revealed a pooled total hemorrhage rate per procedure of 1.8% (95% CI 1.0%-2.5%) for adjuvant (surgery or radiosurgery) and 4.6% (95% CI 2.8%-6.4%) for curative intent. The treatment of aneurysms (p = 0.04) and larger patient populations (p < 0.001) were significant predictors of a lower hemorrhage rate, whereas curative intent (p = 0.04), angiographic obliteration achieved endovascularly (p = 0.003), and a greater number of embolization sessions (p = 0.03) were significant predictors of a higher hemorrhage rate. There were no significant differences in periprocedural hemorrhage rates according to the years evaluated or the embolysate utilized.

CONCLUSIONS

In this study-level meta-analysis, periprocedural hemorrhage was seen after 2.6% of transarterial embolization procedures for cerebral AVMs. The adjuvant use of endovascular embolization, including in the treatment of associated aneurysms and in the presurgical or preradiosurgical setting, was a study-level predictor of significantly lower hemorrhage rates, whereas more aggressive embolization involving curative intent and endovascular angiographic obliteration was a predictor of a significantly higher total hemorrhage rate.

Surgical management of complex brain arteriovenous malformations with hybrid operating technique: study protocol of a prospective registry and a pragmatic clinical trial

BACKGROUND

Complex brain arteriovenous malformations (bAVMs) in ≥3 Spetzler-Martin grades have long been challenges among cerebrovascular diseases. None of the traditional methods, such as microsurgical operation, endovascular intervention, or stereotactic radiotherapy, can completely eliminate complex bAVMs without a risk of neural function deterioration. The multistaged hybrid operation solved part of the challenge but remained risky in the installment procedures and intervals. The one-staged hybrid operation was applied in the surgical treatment of cerebrovascular diseases and proved to be a potentially safe and effective method for curing complex bAVMs. However, lacking the support of high-level evidence, its advantages remain unclear. This study was proposed to validate the benefits and risks of one-staged hybrid operation in the treatment of complex bAVMs, as well as its indications, key technologies, and workflows.

METHODS

The study is being conducted from Jan 2016 to Dec 2020 with 20 cooperation centers. It consists of 2 sets. The registry set is designed as a prospective real-world registry. The trial set is designed as a prospective pragmatic clinical trial, specifically for the patients with perforating arterial feeders. The two sets share a common grouping: the traditional operation group and the one-staged hybrid operation group. The assignment is based on the clinical condition in the registry set and is randomized in the trial set. End points will be evaluated at scheduled time points. The safety and efficiency of one-staged hybrid operation in treating complex bAVMs will be validated.

DISCUSSION

The study is designed for a real-world exploration of benefits and risks of one-staged hybrid operation in the treatment of complex bAVMs. The two-set design reduces the compromise of clinical practice due to the study and improves the statistical power and research quality with a practical sample size. In the study, advantages of the one-staged hybrid operation will be evaluated and compared to those of traditional operation. A spanning development of neurosurgical operation might be facilitated by the study, which means a higher cure rate and lower disability rate in patients with complex bAVMs.

TRIAL REGISTRATION

The study was retrospectively registered in ClinicalTrials.gov ( NCT03774017 ) on 11th Dec, 2018.

Single-stage planning for total cure of grade III-V brain arteriovenous malformations by embolization alone or in combination with microsurgical resection

PURPOSE

There are no established guidelines for treatment of Spetzler-Martin grade III-V brain arteriovenous malformations (bAVMs). The purpose of this study is to report our institutional experience in total obliteration/eradication of grade III-V bAVMs by single-stage planning of embolization combined with microsurgical resection when necessary.

METHODS

All patients harboring Spetzler-Martin (S-M) grade III-V bAVMs treated with single-stage planning between January 2006 and January 2018 were retrospectively reviewed. This treatment paradigm is applicable only to surgically accessible bAVMs and does not include deep-seated bAVMs. Indications for treatment, clinical presentation, imaging characteristics, and treatment outcomes were analyzed. Outcomes were assessed based on modified Rankin Scale.

RESULTS

A total of 31 patients were identified. Seventeen patients (54.8%) presented with hemorrhage, 10 (32.3%) with seizures, 3 (9.7%) with headaches, and 1 (3.2%) with progressive neurological deficit. Based on S-M grading system, 25 patients (80.6%) harbored grade III bAVM, 5 patients had grade IV bAVMs (16.1%), and 1 patient (3.2%) had a grade V bAVM. There were no treatment-related complications in 24/31 (77.4%) patients. Of the total of seven patients with complications, four patients had clinical deterioration. The long-term (> 6-month), non-disabling morbidity (mRS ≤ 2) rate was 6.5%. The long-term, disabling morbidity rate was 3.2% with a mortality of 3.2%. Complete angiographic obliteration was achieved in 30/31 (96.8%) patients.

CONCLUSION

Single-stage treatment strategy can be considered as an alternative to multistage embolization prior to surgery in grade III-V bAVMs. In this study, a high rate of total obliteration with relatively low rates of permanent morbidity and mortality was achieved.

Onyx Embolization for Tentorial Dural Arteriovenous Fistula with Pial Arterial Supply: Case Series and Analysis of Complications

OBJECTIVE

We describe treatment with Onyx embolization in a series of cases of tentorial dural arteriovenous fistula (DAVF) with pial arterial supply. The aim of this study was to analyze the cause of intraoperative hemorrhage and to explore therapeutic strategies.

METHODS

Retrospective review was performed of 53 consecutive patients with DAVF treated by Onyx embolization between February 2009 and December 2014. Tentorial DAVF with pial arterial supply was diagnosed in 6 patients (2 women and 4 men; mean age, 47.3 years ± 10.2), and transarterial Onyx embolization was performed in these patients. Fisher exact test was used to analyze differences of incidence of procedure-related complications.

RESULTS

Intraoperative hemorrhage occurred in 2 of 6 patients with pial arterial supply. One patient died as a result of hemorrhage, and the other patient survived after craniotomy. The incidence of complications for these 6 patients (2 of 6; 33.3%) was significantly higher (P = 0.0309) compared with patients with DAVF without pial arterial supply (1 of 47; 2.1%).

CONCLUSIONS

Pial arterial supply may be a risk factor for intraoperative hemorrhage during transarterial embolization of DAVF through dural feeders. Identification of pial feeders and early superselective occlusion of such feeders are important for safe management.