Microsurgical Treatment of Arteriovenous Malformations: A Single-Center Study Experience

Spetzler-Martin grade I and II cerebral arteriovenous malformations: a propensity-score matched analysis of resection and stereotactic radiosurgery in adult patients

Cerebral arteriovenous malformations (AVMs) are congenital vascular anomalies that can lead to severe complications, including hemorrhage and neurological deficits. This study compares the outcomes of microsurgical resection and stereotactic radiosurgery (SRS) for SM grade I and II AVMs. Out of a large multicenter registry, we identified 180 matched patients with SM grade I and II AVMs treated with either microsurgical resection or SRS between 2010 and 2023. The primary outcomes were AVM obliteration rates and complications; secondary outcomes included neurological status and functional outcomes measured by the modified Rankin Scale (mRS). Propensity score matching (PSM) was utilized to ensure comparability between treatment groups. After PSM, 90 patients were allocated to each treatment group. Significant differences were observed in complete obliteration rates, with resection achieving higher rates compared to SRS in overall cases (97.8% vs. 60.0%, p < 0.001), unruptured AVMs (100% vs. 58.3%, p < 0.001), and ruptured AVMs (95.2% vs. 61.9%, p < 0.001). Functional improvement rates were similar between the groups for overall cases (67.2% in resection vs. 66.7% in SRS, p = 0.95), unruptured AVMs (55.2% in resection vs. 55.6% in SRS, p > 0.9), and ruptured AVMs (78.1% in resection vs. 74.1% in SRS, p = 0.7). Symptomatic complication rates were identical between the groups (11.1% each, p > 0.9), while permanent complication rates were comparable (6.7% in resection vs. 5.6% in SRS, p = 0.8). Resection demonstrated significantly higher complete obliteration rates compared to SRS across all cases, including unruptured and ruptured AVMs. Functional improvement rates were similar between the two treatment groups, with no significant differences in symptomatic or permanent complication rates.

Surgical outcomes and risk factors for overall mortality in brain arteriovenous malformations patients: a retrospective analysis

Background

Brain arteriovenous malformations (AVMs) are challenging vascular lesions. Extensive follow-up studies are necessary to refine the therapeutic algorithm, and to improve long-term survival in these patients. The aim of the study was to assess surgical outcomes, and to evaluate overall long-term mortality in patients treated for brain AVMs.

Methods

This retrospective single-center study included 191 patients with brain AVMs, admitted between 2012 and 2022. Clinical and angiographical particularities have been analyzed, to identify factors that might influence early outcome and overall long-term mortality.

Results

Out of 79 patients undergoing surgery, 51 had ruptured AVMs with total resection achieved in 68 cases (86.1%). Deep venous drainage was associated with incomplete resection. Female sex, admission modified Rankin Scale (mRS) > 2, and eloquent location were independent predictors of poor outcomes. Multiple venous drainage was associated with a higher risk of worsened early outcome. Eloquent brain region involvement, conservative treatment, increasing age, admission mRS > 2, and comorbidities significantly decrease survival in brain AVM patients. Patients treated with interventional treatments had significantly better survival than the conservatively managed ones, when adjusting for age and admission mRS.

Conclusion

The study identified female sex, poor neurologic status on admission and eloquence as independent prognostic factors for a negative outcome after surgery. Patients who received interventional treatment had significantly better survival than patients managed conservatively. We recommend employing tailored, proactive management strategies as they significantly enhance long-term survival in brain AVM patients.

Predicting intraoperative major blood loss in microsurgery for brain arteriovenous malformations

Objective

Intraoperative blood loss poses a great challenge for brain arteriovenous malformation (AVM) microsurgery, although systematic researches are still lacking. This study aimed to identify factors predicting intraoperative major blood loss in brain AVM microsurgery and to investigate its impact on patient outcome. To deal with the fierce bleeding, we introduced a modified hemostatic method, bone-wax (BW) coated bipolar electrocoagulation.

Methods

The authors retrospectively analyzed the clinical data of 131 patients (50/81 in intraoperative major/non-major blood loss cohort) with brain AVMs who underwent microsurgery in our center during the period between January 2018 and April 2023. According to previous studies, major blood loss was defined as blood loss of at least 1,000 mL. The accuracy and objectivity of our grouping methodology were validated by comparing the hemoglobin mass loss, hematocrit loss and factors associated with intraoperative bleeding. Potential clinical and radiological predictors for intraoperative major blood loss were evaluated using a multivariate stepwise logistic regression. And outcomes of patients in the two cohorts were also compared. At last, the performance of BW coated bipolar electrocoagulation in brain AVM microsurgery was illustrated by the case presentation, histological staining and transmission electron microscopy of the coagulated nidus vessels.

Results

Hemoglobin mass loss, hematocrit loss and factors associated with intraoperative bleeding were significant different between the two cohorts. five independent factors predicting intraoperative major blood loss were identified: (1) clinical manifestations; (2,3) location and size of the nidus; (4) deep venous drainage; and (5) the number of draining veins. And the intraoperative major blood loss can not only adversely affect the surgical progression, but also predict poor perioperative outcomes for patients. Regarding the application of BW coated bipolar electrocoagulation, we found the novel hemostatic method exerted efficient hemostatic effect and reduced the damage to the vascular structure in brain AVM microsurgery.

Conclusion

This study proposed a nomogram for neurosurgeons to predict intraoperative major blood loss in brain AVM microsurgery preoperatively. And intraoperative major blood loss is associated with poor patient outcomes. In addition, BW coated bipolar electrocoagulation, can be applied to control ferocious bleeding during brain AVM microsurgery, which still remains further researches.

The difference of functional MR imaging in evaluating outcome of patients with diffuse and compact brain arteriovenous malformation

Microsurgical resection is an effective method to treat brain arteriovenous malformations (BAVMs). Functional magnetic resonance imaging (fMRI) can evaluate the spatial relationship of nidus and eloquent. Diffuse BAVMs are related to poor outcomes postoperatively. The role of fMRI in evaluating outcomes in patients with different nidus types remains unclear. BAVM patients received microsurgical resection were included from a prospective, multicenter cohort study. All patients underwent fMRI evaluation preoperatively and were regularly followed up postoperatively. Diffuse BAVM is radiologically identified as nidus containing normal brain tissue interspersing between malformed vessels. Lesion-to-eloquent distance (LED) was calculated based on the relationship between nidus and eloquent. The primary outcome was 180-day unfavorable neurological status postoperatively. The risk of primary outcome was investigated within different BAVM nidus types. The LED's performance to predict poor outcome was evaluated using area under curve (AUC). 346 BAVM patients were included in this study. 93 (26.9%) patients were found to have a 180-day unfavorable outcome. Multivariate logistic analysis demonstrated LED (odd ratio [OR], 0.44; 0.34-0.57; P < 0.001) and mRS at admission (OR, 2.59; 1.90-3.54; P < 0.001) as factors of unfavorable outcome. Subgroup analysis showed LED and mRS at admission as factors of unfavorable outcome for patients with compact BAVMs (all P < 0.05), but not for patients with diffuse BAVMs. Subsequent analysis showed that LED performed poorly to predict the unfavorable outcome for patients with diffuse BAVMs, compared with patients with compact BAVMs (AUC as 0.69 vs. 0.86, P < 0.05). A larger cutoff value of LED to unfavorable outcome was found in patients with diffuse BAVMs (15 mm) compared with patients with compact BAVMs (4.7 mm). Usage of LED to evaluate postoperative outcome of patients with diffuse BAVMs differs from its use in patients with compact BAVMs. Specific assessment strategy considering BAVM nidus types could help improve patients' outcome. MITASREAVM cohort (unique identifier: NCT02868008, https://clinicaltrials.gov/study/NCT02868008?term=NCT02868008&rank=1 ).

Unruptured Brain Arteriovenous Malformations: A Systematic Review and Meta-Analysis of Mortality and Morbidity in Aruba-Eligible Studies

BACKGROUND

Treating unruptured brain arteriovenous malformations (bAVMs) represent significant challenges, with numerous uncertainties still in debate. The ARUBA trial induced further investigation into optimal management strategies for these lesions. Here, we present a systematic-review and meta-analysis focusing on ARUBA-eligible studies, aiming to correlate patient data with outcomes and discuss key aspects of these studies.

METHODS

Following PRISMA guidelines, we conducted a systematic-review. Variables analyzed included bAVM Spetzler-Martin (SM) grade, treatment modalities, and outcomes such as mortality and neurological deficits. We compared studies with a minimum of 50% cases classified as SM 1-2 lesions and those with less than 50% in this category. Similarly, a comparison between studies with at least 50% microsurgery-cases and those with less than 50% was performed. We examined correlations between mortality incidence, SM distribution, and treatment modalities.

RESULTS

Our analysis included 16 studies with 2.417 patients. The frequency of bAVMs SM-grade 1-2 ranged from 44% to 76%, SM-grade 3 from 19% to 48%, and SM 4-5 from 5 to 23%. Notably, studies with more than 50% cases presenting lesions SM-grade 1-2 presented significantly lower mortality rates than those with less than 50% cases of SM 1-2 lesions (P < 0.001). No significant difference in mortality rates or neurological deficits was identified between studies with more than 50% of microsurgery-cases and those with less than 50%.

CONCLUSIONS

The analysis revealed that studies with a higher proportion of bAVMs presenting SM 1-2 lesions were associated with lower mortality rates. Mortality did not show a significant association with treatment modalities.

Enhancing the quality of evidence, comparability, and reproducibility in brain arteriovenous malformations treated with open surgery research: a systematic review and proposal of a reporting guideline for surgical and clinical outcomes

Brain Arteriovenous Malformations (bAVMs) are rare but high-risk developmental anomalies of the vascular system. Microsurgery through craniotomy is believed to be the mainstay standard treatment for many grades of bAVMs. However, a significant challenge emerges in the existing body of clinical studies on open surgery for bAVMs: the lack of reproducibility and comparability. This study aims to assess the quality of studies reporting clinical and surgical outcomes for bAVMs treated by open surgery and develop a reporting guideline checklist focusing on essential elements to ensure comparability and reproducibility. This is a systematic literature review that followed the PRISMA guidelines with the search in Medline, Embase, and Web of Science databases, for studies published between January 1, 2018, and December 1, 2023. Included studies were scrutinized focusing on seven domains: (1) Assessment of How Studies Reported on the Baseline Characteristics of the Patient Sample; (2) Assessment and reporting on bAVMs grading, anatomical characteristics, and radiological aspects; (3) Angioarchitecture Assessment and Reporting; (4) Reporting on Pivotal Concepts Definitions; (5) Reporting on Neurosurgeon(s) and Staff Characteristics; (6) Reporting on Surgical Details; (7) Assessing and Reporting Clinical and Surgical Outcomes and AEs. A total of 47 studies comprising 5,884 patients were included. The scrutiny of the studies identified that the current literature in bAVM open surgery is deficient in many aspects, ranging from fundamental pieces of information of methodology to baseline characteristics of included patients and data reporting. Included studies demonstrated a lack of reproducibility that hinders building cumulative evidence. A bAVM Open Surgery Reporting Guideline with 65 items distributed across eight domains was developed and is proposed in this study aiming to address these shortcomings. This systematic review identified that the available literature regarding microsurgery for bAVM treatment, particularly in studies reporting clinical and surgical outcomes, lacks rigorous scientific methodology and quality in reporting. The proposed bAVM Open Surgery Reporting Guideline covers all essential aspects and is a potential solution to address these shortcomings and increase transparency, comparability, and reproducibility in this scenario. This proposal aims to advance the level of evidence and enhance knowledge regarding the Open Surgery treatment for bAVMs.