Preoperative embolization of meningiomas with polyvinyl alcohol particles: The benefits are not outweighed by risks

Angiographic Features of Meningiomas Predicting Extent of Preoperative Embolization

BACKGROUND AND OBJECTIVES

Preoperative embolization is used as an endovascular adjunct to surgical resection of meningiomas. However, there is no standardized system to assess the efficacy or extent of embolization during the embolization procedure. We sought to establish a purely angiographic grading system to facilitate consistent reporting of the outcome of meningioma embolization and to characterize the anatomic and other features of meningiomas that predict the degree of devascularization achieved through preoperative embolization.

METHODS

We identified patients with meningiomas who underwent preoperative cerebral angiography and subsequent resection between 2015 and 2021. Demographic, clinical, and imaging data were collected in a research registry. We defined an angiographic devascularization grading scale as follows: grade 0 for no embolization, 1 for partial embolization, 2 for majority embolization, 3 for complete external carotid artery embolization, and 4 for complete embolization.

RESULTS

Eighty consecutive patients were included, 60 of whom underwent preoperative tumor embolization (20 underwent angiography with an intention to treat but ultimately not embolization). Embolized tumors were larger (59.0 vs 35.9 cc; P = .03). Gross total resection, length of stay, and complication rates did not differ among groups. The distribution of arterial feeders differed significantly across tumors in a location-specific manner. Both the tumor location and the identity of arterial feeders were predictive of the extent of embolization. Anterior midline meningiomas were associated with internal carotid (ophthalmic, ethmoidal) supply and lower devascularization grades (P = .03). Tumors fed by meningeal feeders (convexity, falcine, lateral sphenoid wing) were associated with higher devascularization grades (P < .01). The procedural complication rate for tumor embolization was 2.5%.

CONCLUSION

Angiographic outcomes can be graded to indicate the extent of tumor embolization. This system may facilitate consistency of reported angiographic results. In addition, arterial feeders vary in a manner predicted by tumor location, and these patterns correlate with typical degrees of devascularization achieved in those tumor locations.

Enhancing meningioma resection: a comprehensive study on the safety and effectiveness of Onyx™ presurgical embolization

Presurgical embolization (PE) has emerged as an interesting strategy to help turn brain tumor resection more amenable. This study aims to systematically review the safety and effectiveness of Onyx™ PE in meningioma resection. We followed Cochrane Collaboration and PRISMA for systematic review and meta-analysis, querying PUBMED, Cochrane Library, Web of Science, and Embase databases. Major complications were defined as other artery occlusion, visual deficits due to PE, or non temporary nerve damage, while minor included transitory conditions and others without clinical implications. A total of 186 patients were included, in which 120 were WHO grade I (80%), II (16%), and III (4%). Patient baseline characteristics and complications were distributed in groups without or with individual patient data analysis. Individual Patient Data Meta-Analysis (IPDMA) was performed on the last category, comprising 51 meningiomas that underwent Onyx™ PE. Among available data, 70%, 17%, and 13% were WHO grade I, II, and III, respectively. Considering all studies, tumor characteristics regarding grade underscored a certain homogeneity. Complications occurred at a rate of 9% (95% CI, 4 to 14%; I2 = 35%), with the rate of major complications significantly lower at only 1% (95% CI, 0 to 3%; I2 = 32%), whereas of minor complications was 7% (95% CI, 3 to 10%; I2 = 0%). Mean surgery blood loss was 668.7 (95% CI, 534.9 to 835.8; I2 = 0%) in IPDMA. Onyx™ PE is promising for safer surgical meningioma resection, despite limitations. Further studies are required to validate efficacy, enhance patient selection, and refine techniques.

Preoperative Embolization of Meningiomas Facilitates Reduced Surgical Complications and Improved Clinical Outcomes : A Meta-analysis of Matched Cohort Studies

PURPOSE

The utility of preoperative embolization (PE) of intracranial meningiomas is unclear and controversial. The aim of this study was to investigate the effect of PE on meningioma surgical resection by completing a meta-analysis of matched cohort studies.

METHODS

A systematic review and meta-analysis of matched cohort studies was completed to evaluate the effect of PE on meningioma resection and outcomes. Outcome measures included: intraoperative blood loss, major surgical complications, total surgical complications including minor ones, total major complications including major surgical and embolization complications, total overall complications, and postoperative functional independence defined as modified Rankin Score (mRS) of 0-2. Pooled odds ratios (OR) were determined via a fixed effects model.

RESULTS

A total of 6 matched cohort studies were identified with 219 embolized and 215 non-embolized meningiomas. There was no significant difference in intraoperative blood loss between the two groups (P = 0.87); however, the embolization group had a significantly lower odds ratio of major surgically related complications (OR: 0.37, 95% confidence interval, CI: 0.21-0.67, P = 0.0009, I2 = 0%), but no difference in minor surgical complications (P = 0.86). While there was a significantly lower odds ratio of total overall surgical and PE-related complications in PE cases (OR: 0.64, CI: 0.41-1.0, P = 0.05, I2 = 66%), there was no difference in total combined major complications between the groups (OR: 0.57, CI: 0.27-1.18, P = 0.13, I2 = 33%). Lastly, PE was associated with a higher odds ratio of functional independence on postoperative follow-up (OR: 2.3, CI: 1.06-5.02, P = 0.04, I2 = 0%).

CONCLUSION

For certain meningiomas, PE facilitates lower overall complications, lower major surgical complications, and improved functional independence. Further research is required to identify the particular subset of meningiomas that benefit from PE.

Preoperative tumor embolization prolongs time to recurrence of meningiomas: a retrospective propensity-matched analysis

BACKGROUND

Meningiomas are often embolized preoperatively to reduce intraoperative blood loss and facilitate tumor resection. However, the procedure is controversial and its effects have not yet been reported. We evaluated preoperative embolization for meningiomas and its effect on postoperative outcome and recurrence.

METHODS

We retrospectively reviewed the medical records of 186 patients with WHO grade I meningiomas who underwent surgical treatment at our hospital between January 2010 and December 2020. We used propensity score matching to generate embolization and no-embolization groups (42 patients each) to examine embolization effects.

RESULTS

Preoperative embolization was performed in 71 patients (38.2%). In the propensity-matched analysis, the embolization group showed favorable recurrence-free survival (RFS) (mean 49.4 vs 24.1 months; Wilcoxon p=0.049). The embolization group had significantly less intraoperative blood loss (178±203 mL vs 221±165 mL; p=0.009) and shorter operation time (5.6±2.0 hours vs 6.8±2.8 hours; p=0.036). There were no significant differences in Simpson grade IV resection (33.3% vs 28.6%; p=0.637) or overall perioperative complications (21.4% vs 11.9%; p=0.241). Tumor embolization prolonged RFS in a subanalysis of cases who experienced recurrence (n=39) among the overall cases before variable control (mean RFS 33.2 vs 16.0 months; log-rank p=0.003).

CONCLUSIONS

After controlling for variables, preoperative embolization for meningioma did not improve the Simpson grade or patient outcomes. However, it might have effects outside of surgical outcomes by prolonging RFS without increasing complications.

Endovascular Embolization of Intracranial Meningiomas

Although benign in histology, the hypervascularity and skull base location of meningiomas can make them surgically challenging lesions. Preoperative endovascular embolization with superselective microcatheterization of vascular pedicles may be efficacious in decreasing intraoperative transfusion requirements with equivocal postoperative functional benefit. The potential benefits of preoperative embolization should be weighed against the risks of ischemic complications. Appropriate patient selection is critical. All patients should be monitored closely postembolization, and a course of steroids can be considered to minimize neurologic symptoms.

Diagnostic neuroradiology of intracranial meningiomas presenting with hemorrhagic onset: a double center 14-year experience

PURPOSE

This study aims to increase awareness of the hemorrhagic presentation of intracranial meningiomas in the emergency department and present clues for neuroradiological diagnosis, which is crucial for pertinent management. We described the prevalence of hemorrhage in a large population of meningioma patients, with emphasis on clinical presentation, computed tomography (CT), magnetic resonance (MR), and digital subtraction angiography (DSA) findings.

METHODS

This retrospective analysis has been performed at two reference institutions between January 2002 and December 2015, and includes 1304 patients with histologically proven newly diagnosed intracranial meningioma. Clinical features and neuroradiological findings of intracranial meningiomas presenting with hemorrhage have been reviewed.

RESULTS

Twenty-four patients (1.8%, 16 females, 8 males, age range: 29-88 years) were found to have spontaneous hemorrhagic onset of the newly diagnosed meningioma. A sudden onset occurred in 23/24 patients. Sixteen patients showed isolated intralesional hemorrhage, four had subdural hematomas, and the remaining four presented combined intralesional and subarachnoid (n = 2) or intraventricular (n = 2) hemorrhages. In 13 patients, CT showed both the hemorrhage and the meningioma. In the other 11 patients, diagnosis was achieved by emergency or early surgery (n = 5), MRI (n = 5), and DSA (n = 1).

CONCLUSIONS

The presence of an underlying meningioma has to be considered in the differential diagnosis of spontaneous intracranial hemorrhage, although this is a rare event. CT, MRI, and occasionally DSA were useful to obtain the diagnosis; however, in up to a fifth of patients, this was achieved at surgery.

Clinical Outcomes and Complications of Preoperative Embolization for Intracranial Giant Meningioma Tumorectomy: A Retrospective, Observational, Matched Cohort Study

Objective

The potential benefits of preoperative embolization for intracranial meningiomas are still under debate. We aimed to investigate whether preoperative embolization can improve surgical and functional outcomes, based on controlling patient- and tumor-related confounding factors.

Methods

We reviewed all meningioma cases in our department from January 2016 to May 2021. Cases in the nonembolization cohort were matched to the embolization cohort by 1:1 ratio propensity score matching, through controlling patient- and tumor-related confounds. Surgical outcomes, complications, and functional outcomes were retrospectively compared between these two groups.

Results

Sixty-six cases in each group were included in our study after being matched. We did not find any significant differences of estimated blood loss (600.00 (400) vs. 500.00 (500.00) ml, p = 0.31), decrease of HGB level (30.81 ± 15.82 vs. 26.59 ± 12.90 g/L, p = 0.09), gross total resection rate (74.24% vs. 77.27%, p = 0.68), surgical time (302.50 (136) vs. 300.00 (72) min, p = 0.48), blood transfusion rates (53.03% vs. 42.42%, p = 0.35), blood transfusion volume [650.00 (657.50) vs. 535.00 (875.00) ml, p = 0.63] between the embolization group and nonembolization group. The number of patients who experience postsurgery complications were significantly higher in the nonembolization group (39.39% vs. 21.21%, p = 0.02). Patients in the nonembolization group were more likely to have a higher rate of mRS decline postsurgery (31.82% vs. 15.15%, p = 0.04).

Conclusion

Our study showed significant lower rates of surgical complications and long-term disabilities of meningioma patients treated with preoperative embolization. There were no significant differences in estimated blood loss, surgical time, and blood transfusion volume between embolization and nonembolization groups.

EANO guideline on the diagnosis and management of meningiomas

Meningiomas are the most common intracranial tumors. Yet, only few controlled clinical trials have been conducted to guide clinical decision making, resulting in variations of management approaches across countries and centers. However, recent advances in molecular genetics and clinical trial results help to refine the diagnostic and therapeutic approach to meningioma. Accordingly, the European Association of Neuro-Oncology (EANO) updated its recommendations for the diagnosis and treatment of meningiomas. A provisional diagnosis of meningioma is typically made by neuroimaging, mostly magnetic resonance imaging. Such provisional diagnoses may be made incidentally. Accordingly, a significant proportion of meningiomas, notably in patients that are asymptomatic or elderly or both, may be managed by a watch-and-scan strategy. A surgical intervention with tissue, commonly with the goal of gross total resection, is required for the definitive diagnosis according to the WHO classification. A role for molecular profiling including gene panel sequencing and genomic methylation profiling is emerging. A gross total surgical resection including the involved dura is often curative. Inoperable or recurrent tumors requiring treatment can be treated with radiosurgery, if the size or the vicinity of critical structures allows that, or with fractionated radiotherapy (RT). Treatment concepts combining surgery and radiosurgery or fractionated RT are increasingly used, although there remain controversies regard timing, type, and dosing of the various RT approaches. Radionuclide therapy targeting somatostatin receptors is an experimental approach, as are all approaches of systemic pharmacotherapy. The best albeit modest results with pharmacotherapy have been obtained with bevacizumab or multikinase inhibitors targeting vascular endothelial growth factor receptor, but no standard of care systemic treatment has been yet defined.

Does preoperative embolization improve outcomes of meningioma resection? A systematic review and meta-analysis

Current evidence regarding the benefit of preoperative embolization (POE) of meningiomas is inconclusive. This systematic review and meta-analysis aims to evaluate the safety profile of the procedure and to compare outcomes in embolized versus non-embolized meningiomas. PubMed was queried for studies after January 1990 reporting outcomes of POE. Pertinent variables were extracted and synthesized from eligible articles. Heterogeneity was assessed using I², and random-effects model was employed to calculate pooled 95% CI effect sizes. Publication bias was assessed using funnel plots and Harbord's and Begg's tests. Meta-analyses were used to assess estimated blood loss and operative duration (mean difference; MD), gross-total resection (odds ratio; OR), and postsurgical complications and postsurgical mortality (risk difference; RD). Thirty-four studies encompassing 1782 preoperatively embolized meningiomas were captured. The pooled immediate complication rate following embolization was 4.3% (34 studies, n = 1782). Although heterogeneity was moderate to high (I² = 35-86%), meta-analyses showed no statistically significant differences in estimated blood loss (8 studies, n = 1050, MD = 13.9 cc, 95% CI = -101.3 to 129.1), operative duration (11 studies, n = 1887, MD = 2.4 min, 95% CI = -35.5 to 30.8), gross-total resection (6 studies, n = 1608, OR = 1.07, 95% CI = 0.8-1.5), postsurgical complications (12 studies, n = 2060, RD = 0.01, 95% CI = -0.04 to 0.07), and postsurgical mortality (12 studies, n = 2060, RD = 0.01, 95% CI = 0-0.01). Although POE is relatively safe, no clear benefit was observed in operative and postoperative outcomes. However, results must be interpreted with caution due to heterogeneity and selection bias between studies. Well-controlled future investigations are needed to define the patient population most likely to benefit from the procedure.

Preoperative embolization versus no embolization for WHO grade I intracranial meningioma: a retrospective matched cohort study

OBJECTIVE

The controversy continues over the clinical utility of preoperative embolization for reducing tumor vascularity of intracranial meningiomas prior to resection. Previous studies comparing embolization and nonembolization patients have not controlled for detailed tumor parameters before assessing outcomes.

METHODS

The authors reviewed the cases of all patients who underwent resection of a WHO grade I intracranial meningioma at their institution from 2008 to 2016. Propensity score matching was used to generate embolization and nonembolization cohorts of 52 patients each, and a retrospective review of clinical and radiological outcomes was performed.

RESULTS

In total, 52 consecutive patients who underwent embolization (mean follow-up 34.8 ± 31.5 months) were compared to 52 patients who did not undergo embolization (mean follow-up 32.8 ± 28.7 months; p = 0.63). Variables controlled for included patient age (p = 0.82), tumor laterality (p > 0.99), tumor location (p > 0.99), tumor diameter (p = 0.07), tumor invasion into a major dural sinus (p > 0.99), and tumor encasement around the internal carotid artery or middle cerebral artery (p > 0.99). The embolization and nonembolization cohorts did not differ in terms of estimated blood loss during surgery (660.4 ± 637.1 ml vs 509.2 ± 422.0 ml; p = 0.17), Simpson grade IV resection (32.7% vs 25.0%; p = 0.39), perioperative procedural complications (26.9% vs 19.2%; p = 0.35), development of permanent new neurological deficits (5.8% vs 7.7%; p = 0.70), or favorable modified Rankin Scale (mRS) score (a score of 0-2) at last follow-up (96.0% vs 92.3%; p = 0.43), respectively. When comparing the final mRS score to the preoperative mRS score, patients in the embolization group were more likely than patients in the nonembolization group to have an improvement in mRS score (50.0% vs 28.8%; p = 0.03).

CONCLUSIONS

After controlling for patient age, tumor size, tumor laterality, tumor location, tumor invasion into a major dural sinus, and tumor encasement of the internal carotid artery or middle cerebral artery, preoperative meningioma embolization intended to decrease tumor vascularity did not improve the surgical outcomes of patients with WHO grade I intracranial meningiomas, but it did lead to a greater chance of clinical improvement compared to patients not treated with embolization.

Angiography and embolization of meningiomas

The preoperative embolization of meningiomas has been part of the surgical treatment of large meningiomas for over 45 years. During that time there have been huge advances in the field of endovascular surgery with respect to techniques and instrumentation. Angiography and embolization are usually reserved for the largest tumors where there are concerns over potential blood loss with surgical excision. In this chapter, we discuss the technical aspects of angiography and embolization as well as results and complications.

Postembolization Change in Magnetic Resonance Imaging Contrast Enhancement of Meningiomas Is a Better Predictor of Intraoperative Blood Loss Than Angiography

BACKGROUND

Preoperative embolization of meningiomas to reduce tumor vascularity and intraoperative blood loss remains controversial. Incomplete devascularization on angiography is not significantly correlated with intraoperative estimated blood loss (EBL). Magnetic resonance imaging (MRI) may provide a better assessment of devascularization and prediction of EBL.

METHODS

We retrospectively analyzed patients undergoing preoperative embolization for intracranial meningiomas. Cohorts based on postembolization devascularization (>50% vs. ≤50%) were compared.

RESULTS

Of 84 patients with meningioma undergoing preoperative embolization, 35 (42%) had a postembolization MRI before resection and met study inclusion criteria. The mean tumor diameter was 4.9 ± 1.3 cm, and mean intraoperative EBL was 576 ± 341 mL. Compared with MRI, angiography overestimated devascularization in 22 patients (63%). Using pre- versus postembolization MRIs, 17 (49%) patients had a >50% decrease in enhancement, which was associated with lower mean intraoperative blood loss (444 ± 255 mL) compared with 17 patients with ≤50% devascularization (700 ± 374 mL) (P = 0.03). On angiography, the 22 (63%) patients who demonstrated >50% devascularization during embolization did not statistically differ in intraoperative EBL when compared with 13 (37%) patients with <50% angiographic devascularization. Patients with a ≤50% decrease in contrast enhancement on postembolization MRI were 9 times more likely to lose >500 mL blood intraoperatively during resection (95% confidence interval 1.6-54, P = 0.01).

CONCLUSIONS

Postembolization contrast-enhanced MRI is a better predictor of intraoperative blood loss during meningioma resection than postembolization angiography, which overestimates the degree of embolic devascularization. Postembolization preoperative MRI is warranted for optimal patient management.

Predictors of preoperative endovascular embolization of meningiomas: subanalysis of anatomic location and arterial supply

Introduction

Endovascular embolization of intracranial meningiomas is commonly used as an adjunct to surgical resection. We sought to describe the anatomic locations and vascular supplies of meningiomas to identify characteristics predictive of successful preoperative endovascular embolization.

Methods

We conducted a retrospective review of 139 meningioma cases receiving cerebral angiograms for possible preoperative endovascular embolization at our institution between December 2000 and March 2017. The extent of embolization, arterial supply, anatomic location, and procedural complications were recorded for each case. Univariate and multivariate analyses were performed to identify tumor characteristics that predicted successful embolization.

Results

Of the total meningioma patients undergoing preoperative angiography, 78% (108/139) were successfully embolized, with a 2.8% periprocedural complication rate (3/108). Within the subset of patients with successful embolization, 31% (33/108) achieved complete angiographic embolization. Significant multivariate predictors of embolization (either partial or complete) were convexity/parasagittal locations (OR 5.15, 95% CI 0.93 to 28.54, p=0.060), meningohypophyseal trunk (MHT, OR 4.65, 95% CI 1.63 to 13.23, p=0.004), middle meningeal artery (MMA, OR 10.89, 95% CI 3.43 to 34.64, p<0.001), and ascending pharyngeal artery supply (APA, OR 9.96, 95% CI 1.88 to 52.73, p=0.007). Significant predictors for complete embolization were convexity/parasagittal locations (OR 4.79, 95% CI 1.66 to 13.84, p=0.004) and embolized APA supply (OR 6.94, 95% CI 1.90 to 25.39, p=0.003). Multiple arterial supply was a negative predictor of complete embolization (OR 0.38, 95% CI 0.15 to 0.98, p=0.05).

Conclusions

Tumor characteristics can be used to predict the likelihood of preoperative meningioma embolization. Parasagittal and convexity meningiomas, and those with APA supply, are most likely to achieve complete angiographic embolization.

Preoperative Embolization Versus Direct Surgery of Meningiomas: A Meta-Analysis

BACKGROUND

Preoperative embolization (POE) of meningioma has been established to facilitate surgical resection, which may reduce intraoperative blood loss and surgical time. However, no consensus has been achieved in meningioma treatment and no meta-analysis has been conducted. The purpose of this study was to perform a systematic review and meta-analysis and provide evidence of the efficacy of meningioma treatment with POE and direct surgery.

METHODS

This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. A systematic search was performed using PubMed and EMBASE. Meta-analysis was performed using the risk ratio of overall complication, mean difference (MD) of blood loss, and surgical time. The I² statistic was used to assess the heterogeneity.

RESULTS

Eight studies (1 randomized controlled trial and 7 non-randomized controlled trials) were included, in which 510 patients met the inclusion criteria. We found that preoperative embolization for patients with meningioma did not increase the overall complication rate (risk ratio = 0.92, 95% confidence interval [CI] 0.61-1.38) and can significantly reduce intraoperative blood loss (MD = -65.10, 95% CI -124.76 to -20.82) and surgical time (MD = -38.48, 95% CI -64.03 to -12.93) compared with the control patients. No significant publication bias was observed.

CONCLUSIONS

This meta-analysis supports the hypothesis that POE of meningioma is a useful adjunct in meningioma treatment. This technique helps reduce blood loss and surgical time during meningioma resection.

Preoperative embolization of skull base meningiomas: current indications, techniques, and pearls for complication avoidance

Skull base meningiomas are technically challenging tumors to treat because of their deep vascular supply that can preclude early devascularization during resection. Preoperative embolization of these arterial feeders is thought to decrease blood loss and facilitate resection; however, given the complex and varied anatomy of these skull base lesions, preoperative embolization is not without risk. It is essential for both endovascular and skull base neurosurgeons to understand these risks in light of the potential benefits. The authors review the vascular anatomy of skull base meningiomas, indications for preoperative devascularization, endovascular techniques, and published results regarding embolization of these lesions.