Preoperative embolization of skull base meningiomas: A systematic review

Preoperative Radiographic Features Independently Predict High Blood Loss During Intracranial Meningioma Resection: A Case-Control Study

BACKGROUND

Surgical resection of intracranial meningioma carries the risk of several complications, including intraoperative blood loss. The objective of this study was to investigate preoperative clinical and radiographic factors predictive of intraoperative estimated blood loss (EBL).

METHODS

This case-control study evaluated EBL for all adults who underwent intracranial meningioma resection from January, 2010 to December, 2021 at our institution. Fifty cases of high EBL (i.e., ≥500 mL) and 75 instances of low EBL (i.e., <500 mL) were randomly selected. Patients were excluded if they had a recurrent meningioma, preoperative embolization, or lack of imaging data. A multivariable logistic regression model of high EBL likelihood was created.

RESULTS

A total of 92 patients met eligibility criteria, with 48 (52%) cases of high EBL. Bivariable analyses identified maximal tumor diameter, intratumoral flow voids, skull base location, and dural venous sinus invasion as potential predictors of high EBL. Multivariable regression found intratumoral flow voids (adjusted odds ratio [aOR] = 5.68 [1.52-21.23], P = 0.009), maximal tumor diameter (aOR = 1.58 [1.11-2.25] per 1-cm increase, P = 0.01), and skull base location (aOR = 3.35 [1.19-9.41], P = 0.02) to be independent predictors of high EBL.

CONCLUSIONS

Intratumoral flow voids, larger maximal tumor diameter, and skull base location were independently predictive of EBL ≥500 mL. Intratumoral flow void presence was the strongest predictor, with 5.68 times the odds of high EBL. Each 1-cm increase in tumor diameter had 58% greater odds of high EBL. Skull base location was associated with 3.35 times the odds of high EBL. These results can inform preoperative patient counseling and blood management preparation.

Quantifying extent of meningioma preoperative embolization through volumetric analysis: A retrospective case series

BACKGROUND

Endovascular embolization is an adjunct to meningioma resection. Isolating the effectiveness of embolization is difficult as MR imaging is typically performed before embolization and after resection, and volumetric assessment of embolization on 2D angiographic imaging is challenging. We investigated the correlation between 2D angiographic and 3D MR measurements of meningioma devascularization following embolization.

METHODS

We implemented a protocol for postembolization, preresection MRI. Angiographic devascularization was graded according to reduction of tumor blush from 1 (partial embolization) to 4 (complete embolization with no residual circulation supply). Volumetric extent of embolization was quantified as the percent of tumor contrast enhancement lost following embolization. Tumor embolization was analyzed according to tumor location and vascular supply.

RESULTS

Thirty consecutive patients met inclusionary criteria. Grade 1 devascularization was achieved in 7% of patients, grade 2 in 43%, grade 3 in 20%, and grade 4 in 30%. Average extent of embolization was 37 ± 6%. Extent of tumor embolization was low (<25%) in 40%, moderate (25%-75%) in 40%, and high (>75%) in 20% of patients. Convexity, parasagittal/falcine and sphenoid wing tumors were found to have distinct vascular supply patterns and extent of embolization. Angiographic devascularization grade was significantly correlated with volumetric extent of tumor embolization (p < 0.001, r = 0.758).

CONCLUSION

This is the first study to implement postembolization, preoperative MRI to assess extent of embolization prior to meningioma resection. The study demonstrates that volumetric assessment of contrast reduction following embolization provides a quantitative and spatially resolved framework for assessing extent of tumor embolization.

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.

Relevance of the Foramen of Vesalius for Preoperative Tumor Embolization in Skull Base Meningioma

OBJECTIVE

The objective of this study was to investigate the role of the foramen of Vesalius (FV) in the pathogenesis of skull base meningioma by analyzing data from various multi-image modalities.

METHODS

For this single-center retrospective study, 39 consecutive patients with skull base meningioma who underwent tumor resection between January 2020 and March 2023 were enrolled. The anatomical and pathological characteristics of the FV were evaluated using computed tomography and 3-dimensional digital subtraction angiography. The clinical significance of the FV in tumor hemodynamics and treatment, such as preoperative tumor embolization, was investigated using the 3-dimensional digital subtraction angiography/computed tomography fusion images.

RESULTS

We identified FV in 52% (17/27) of the finally included patients. In 10 (30%) patients, the FV was found bilaterally with no significant variation in appearance between the healthy and tumor-affected sides (P = 0.786). The mean FV diameter was significantly larger on the tumor-affected side (P = 0.010). No significant anatomical differences, like duplication and partial assimilation with the foramen ovale, were observed between the 2 sides. The FV was involved in venous skull base perfusion around the tumor in 9 cases. In 4 cases where it was the pathway for tumor feeders, preoperative tumor embolization via the FV resulted in disappearance of the tumor stain. No complications associated with endovascular treatment were observed.

CONCLUSIONS

This study elucidated the anatomical asymmetry of the FV and its role in the hemodynamics of skull base meningioma. Our findings highlight the significance of performing anatomical and pathological evaluations of the FV in determining treatment strategies, including preoperative embolization, for skull base lesions.

Tumor Embolization via the Meningohypophyseal and Inferolateral Trunk in Patients with Skull Base Tumors Using the Distal Balloon Protection Technique

BACKGROUND AND PURPOSE

Tumor embolization through the meningohypophyseal trunk and inferolateral trunk is known to be effective in skull base tumors; however, microcatheter cannulation into these arteries is difficult, and the number of cases that can be safely embolized is limited. In this study, we present a novel embolization procedure for the meningohypophyseal trunk and inferolateral trunk using the distal balloon protection technique and detail its clinical efficacy and complication risks. We developed this procedure to allow safe embolization in patients who cannot be adequately cannulated with microcatheters into these arteries.

MATERIALS AND METHODS

Patients who underwent meningohypophyseal trunk or inferolateral trunk embolization using the distal balloon protection technique for skull base tumors at our institution between 2010 and 2023 were included. In this procedure, the ICA was temporarily occluded with a balloon at the ophthalmic artery bifurcation, the microcatheter was guided to the meningohypophyseal trunk or inferolateral trunk vicinity, and embolic particles were injected into the arteries. The balloon was deflated after the embolic particles that had refluxed into the ICA were aspirated.

RESULTS

A total of 25 meningohypophyseal trunks and inferolateral trunks were embolized during 21 operations. Of these 25 arteries, only 9 (36.0%) were successfully cannulated with microcatheters. Nevertheless, effective embolization was achieved in all cases. Permanent complications occurred in only 1 case (4.8%) in which the central retinal artery was occluded during inferolateral trunk embolization, resulting in a visual field defect. No permanent complications resulting from the embolic cerebral infarction were observed. Of 16 cases that underwent MR imaging within a week after embolization, however, 11 (68.8%) demonstrated embolic cerebral infarctions.

CONCLUSIONS

In patients with skull base tumors with meningohypophyseal trunk or inferolateral trunk feeders that cannot be catheterized directly, embolization using the distal balloon protection technique for tumor supply can be considered as a salvage technique.

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.

A pregnant woman with a giant bilateral parietal hemangiopericytoma underwent multiple surgeries and radiotherapy: a case report and literature review

Intracranial hemangiopericytoma is a rare invasive tumor originating from mesenchymal fibroblasts and is prone to local recurrence and distant metastasis. This study reports a case of a 27-year-old woman who presented with severe headache, nausea and vomiting for two weeks at thirty-three weeks of gestation. Cranial magnetic resonance imaging (MRI) demonstrated a giant lesion in the bilateral parietal lobe with a size of 5.12x9.19x6.03 cm and severe edema in the surrounding brain tissue. The patient underwent four operations and 3 gamma knife radiosurgery procedures and is recovering well now. The histopathology findings showed hemangiopericytoma and STAT6 and CD34 positivity after the first and second surgeries. Because of tumor progression, the patient received gamma knife radiosurgery at 1, 3, and 4 years after the first operation. Total tumor resection was achieved in the fourth surgery. Nevertheless, the patient showed malignant transformation to from low-grade to high-grade hemangiopericytoma.

Staged Strategies to Deal with Complex, Giant, Multi-Fossa Skull Base Tumors

Given the complex and multifaceted nature of resecting giant tumors in the anterior, middle, and, to a lesser extent, the posterior fossa, we present two example strategies for navigating the intricacies of such tumors. The foundational premise of these two approaches is based on a two-stage method that aims to improve the visualization and excision of the tumor. In the first case, we utilized a combined endoscopic endonasal approach and a staged modified pterional, pretemporal, with extradural clinoidectomy, and transcavernous approach to successfully remove a giant pituitary adenoma. In the second case, we performed a modified right-sided pterional approach with pretemporal access and extradural clinoidectomy. This was followed by a transcortical, transventricular approach to excise a giant anterior clinoid meningioma. These cases demonstrate the importance of performing staged operations to address the challenges posed by these giant tumors.

AhR and HIF-1α Signaling Pathways in Benign Meningioma under Hypoxia

The role of hypoxia in benign meningiomas is less clear than that in the malignant meningiomas. Hypoxia-induced transcription factor 1 subunit alpha (HIF-1α) and its downstream signaling pathways play a central role in the mechanism of hypoxia. HIF-1α forms a complex with the aryl hydrocarbon receptor nuclear translocator (ARNT) protein and can compete for ARNT with aryl hydrocarbon receptor (AhR). In this work, the status of HIF-1α- and AhR-dependent signaling pathways was investigated in World Health Organization (WHO) grade 1 meningioma and patient-derived tumor primary cell culture under hypoxic conditions. mRNA levels of HIF-1α, AhR, and of their target genes as well as of ARNT and nuclear receptor coactivator NCOA2 were determined in tumor tissues from patients in whom the tumor was promptly removed either with or without prior endovascular embolization. Using the patient-derived nonembolized tumor primary cell culture, the effects of a hypoxia mimetic cobalt chloride (CoCl₂) and an activator of the AhR signaling pathway benzo(α)pyrene (B[a]P) on mRNA levels of HIF-1α, AhR, and their target genes were investigated. Our findings show active functioning of AhR signaling in meningioma tissue of patients with tumor embolization and crosstalk between HIF-1α and AhR signaling in meningeal cells under hypoxia.

Surgical Therapy of Non-Skull Base Meningiomas

In a previous chapter, the surgical management of skull base meningiomas were discussed. However, the most common meningiomas that are diagnosed and operated on are non-skull base tumors located in the parasagittal/parafalcine region and convexity, and more rarely along the tentorium, and in an intraventricular location. These tumors present their own unique set of challenges given their unique anatomy and tend to be more biologically aggressive compared to skull base meningiomas, thereby reinforcing the importance of obtaining a gross total resection if possible, in order to delay recurrence. In this chapter we will cover the surgical management of non-skull base meningiomas with technical considerations for tumors located in each of the anatomical areas listed above.

Surgical results of 158 petroclival meningiomas with special focus on standard craniotomies

Objective

The goal of this retrospective study is the evaluation of risk factors for postoperative neurological deficits after petroclival meningioma (PCM) surgery with special focus on standard craniotomies.

Materials and methods

One-hundred-fifty-eight patients were included in the study, of which 133 patients suffered from primary and 25 from recurrent PCM. All patients were operated on and evaluated concerning age, tumor size, histology, pre- and postoperative cranial nerve (CN) deficits, morbidity, mortality, and surgical complications. Tumor-specific features—e.g., consistency, surface, arachnoid cleavage, and location—were set in a four-grade classification system that was used to evaluate the risk of CN deficits and tumor resectability.

Results

After primary tumor resection, new CN deficits occurred in 27.3% of patients. Preoperative ataxia improved in 25%, whereas 10% developed new ataxia. Gross total resection (GTR) was achieved in 59.4%. The morbidity rate, including hemiparesis, shunt-dependence, postop-hemorrhage, and tracheostomy was 22.6% and the mortality rate was 2.3%. In recurrent PCM surgery, CN deficits occurred in 16%. GTR could be achieved in three cases. Minor complications occurred in 20%. By applying the proposed new classification system to patients operated via standard craniotomies, the best outcome was observed in type I tumor patients (soft tumor consistency, smooth surface, plane arachnoid cleavage, and unilateral localization) with GTR in 78.7% (p < 0.001) and 11.9% new CN deficits (p = 0.006).

Conclusion

Standard craniotomies as the retrosigmoid or subtemporal/pterional approaches are often used for the resection of PCMs. Whether these approaches are sufficient for GTR—and avoidance of new neurological deficits—depends mainly on the localization and intrinsic tumor-specific features.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11060-022-04105-5.

Tumor Embolization through Meningohypophyseal and Inferolateral Trunks is Safe and Effective

BACKGROUND AND PURPOSE

Skull base tumors are commonly supplied by dural branches of the meningohypophyseal and inferolateral trunks. Embolization through these arteries is often avoided due to technical challenges and inherent risks; however, successful embolization can be a valuable surgical adjunct. We aimed to review the success and complications in our series of tumor embolizations through the meningohypophyseal and inferolateral trunks.

MATERIALS AND METHODS

We performed a retrospective review of patients with tumor treated with preoperative embolization at our institution between 2010 and 2020. We reviewed the following data: patients' demographics, tumor characteristics, endovascular embolization variables, and surgical results including estimated blood loss, the need for transfusion, and operative time.

RESULTS

Among 155 tumor embolization cases, we identified 14 patients in whom tumor embolization was performed using the meningohypophyseal (n = 13) or inferolateral (n = 4) trunk. In this group of patients, on average, 79% of tumors were embolized. No mortality or morbidity from the embolization procedure was observed in this subgroup of patients. The average estimated blood loss in the operation was 395 mL (range, 200-750 mL). None of the patients required a transfusion, and the average operative time was 7.3 hours.

CONCLUSIONS

Some skull base tumors necessitate embolization through ICA branches such as the meningohypophyseal and inferolateral trunks. Our series demonstrates that an effective and safe embolization may be performed through these routes.

Operative Technique: Angiomatoid Fibrous Histiocytoma—Unique Case and Management

Objective  We describe the first jugular foramen angiomatoid fibrous histiocytoma (AFH) case and the first treatment with preoperative endovascular embolization. AFH is a rare intracranial neoplasm, primarily found in pediatric patient extremities. With an increase in AFH awareness and a well-described genetic profile, intracranial prevalence has also subsequently increased.

Study Design  We compare this case to previously reported cases using PubMed/Medline literature search, which was performed using the algorithm [“intracranial” AND “angiomatoid fibrous histiocytoma”] through December 2020 (23 manuscripts with 46 unique cases).

Patient  An 8-year-old female presented with failure to thrive and right-sided hearing loss. Work-up revealed an absence of right-sided serviceable hearing and a large jugular foramen mass. Angiogram revealed primary arterial supply from the posterior branch of the ascending pharyngeal artery, which was preoperatively embolized.

Intervention  Gross total resection was performed via a translabyrinthine approach.

Conclusion  The case presented is unique; the first reported AFH at the jugular foramen and the first reported case utilizing preoperative embolization. Preoperative embolization is a relatively safe technique that can improve the surgeon's ability to perform a maximally safe resection, which may decrease the need for adjuvant radiation in rare skull base tumors in young patients.

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.

Surgical management of anterior clinoidal meningiomas: consensus statement on behalf of the EANS skull base section

BACKGROUND

The optimal management of clinoidal meningiomas (CMs) continues to be debated.

METHODS

We constituted a task force comprising the members of the EANS skull base committee along with international experts to derive recommendations for the management of these tumors. The data from the literature along with contemporary practice patterns were discussed within the task force to generate consensual recommendations.

RESULTS AND CONCLUSION

This article represents the consensus opinion of the task force regarding pre-operative evaluations, patient's counselling, surgical classification, and optimal surgical strategy. Although this analysis yielded only Class B evidence and expert opinions, it should guide practitioners in the management of patients with clinoidal meningiomas and might form the basis for future clinical trials.

Petroclival meningiomas: update of current treatment and consensus by the EANS skull base section

BACKGROUND

The optimal management of petroclival meningiomas (PCMs) continues to be debated along with several controversies that persist.

METHODS

A task force was created by the EANS skull base section along with its members and other renowned experts in the field to generate recommendations for the management of these tumors. To achieve this, the task force reviewed in detail the literature in this field and had formal discussions within the group.

RESULTS

The constituted task force dealt with the existing definitions and classifications, pre-operative radiological investigations, management of small and asymptomatic PCMs, radiosurgery, optimal surgical strategies, multimodal treatment, decision-making, and patient's counselling.

CONCLUSION

This article represents the consensually derived opinion of the task force with respect to the management of PCMs.

Advances in Multidisciplinary Management of Skull Base Meningiomas

The surgical management of Skull Base Meningiomas (SBMs) has radically changed over the last two decades. Extensive surgery for patients with SBMs represents the mainstream treatment; however, it is often challenging due to narrow surgical corridors and proximity to critical neurovascular structures. Novel surgical technologies, including three-dimensional (3D) preoperative imaging, neuromonitoring, and surgical instruments, have gradually facilitated the surgical resectability of SBMs, reducing postoperative morbidity. Total removal is not always feasible considering a risky tumor location and invasion of surrounding structures and brain parenchyma. In recent years, the use of primary or adjuvant stereotactic radiosurgery (SRS) has progressively increased due to its safety and efficacy in the control of grade I and II meningiomas, especially for small to moderate size lesions. Patients with WHO grade SBMs receiving subtotal surgery can be monitored over time with surveillance imaging. Postoperative management remains highly controversial for grade II meningiomas, and depends on the presence of residual disease, with optional upfront adjuvant radiation therapy or close surveillance imaging in cases with total resection. Adjuvant radiation is strongly recommended in patients with grade III tumors. Although the currently available chemotherapy or targeted therapies available have a low efficacy, the molecular profiling of SBMs has shown genetic alterations that could be potentially targeted with novel tailored treatments. This multidisciplinary review provides an update on the advances in surgical technology, postoperative management and molecular profile of SBMs.

Pterygovaginal artery as a target of embolization before endoscopic skull base surgery

BACKGROUND

The pterygovaginal artery (PtVA), a recurrent branch of the internal maxillary artery (IMA), can be a feeder of skull base tumors. Preoperative embolization can help endoscopic resection of hypervascular lesions, which is performed under a narrow surgical space with restricted instrumental maneuverability.

METHODS

We performed preoperative embolization in five cases with hypervascular skull base lesions supplied by the PtVA, four of which were resected via endoscopic endonasal approach. In two cases, selective PtVA embolization through the distal IMA was successfully conducted.

RESULTS

In all the cases, intraoperative bleeding during endoscopic resection was easily controlled. The medial and lateral origins of the PtVA from the IMA were demonstrated by cone-beam CT images reconstructed from three-dimensional rotational angiography, and anastomoses around the eustachian tube and soft palate were visualized by superselective angiography.

CONCLUSIONS

The PtVA embolization can be an effective strategy before endoscopic skull base tumor resection. When embolizing through the PtVA, clinicians should be aware of its anatomical variations and dangerous anastomoses. Understanding the surrounding angioarchitecture by angiographic techniques helps ensure safe embolization.

Cone-Beam Computed Tomography Fusion Technique for Vascular Assessment of Skull Base Meningiomas

OBJECTIVE

Cone-beam computed tomography (CBCT) images for skull base tumors provide detailed vascular information and localization in regard to surrounding bony structures. We report use of the CBCT fusion technique for skull base meningiomas.

METHODS

Six patients with petroclival or petrotentorial meningiomas supplied by multiple arterial systems were preoperatively evaluated using CBCT fusion imaging. Fusion images were reconstructed from three-dimensional rotational angiography with contrast agent injections from the internal carotid artery (ICA) and external carotid artery in 4 cases, vertebral artery and external carotid artery in 1 case, and ICA and vertebral artery in 1 case.

RESULTS

The feeding pedicles and tumor stains from 2 arterial systems were differentiated by separate colors. The courses and territories of the ICA dural feeders or ICA/vertebral artery pial feeders were easily distinguished from the external carotid artery dural feeders. Anastomoses between thin feeders from different arterial systems could be detected. Mixed stain (stain with both colors) was observed in some tumor compartments, suggesting dual supply from 2 arterial systems and the presence of peritumoral anastomoses. All patients underwent preoperative embolization without complications.

CONCLUSIONS

CBCT fusion images clearly visualized the feeders from each arterial system, the vascular compartments within the tumor, and possible peritumoral anastomoses. This technique provides a substantial contribution to both preoperative embolization and surgical resection of skull base meningiomas.

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.

Transarterial Embolization of a Parasellar Hypervascular Tumor

Embolization of hypervascular tumors has been widely performed for over four decades, particularly for preoperative meningioma. Several benefits of preoperative embolization have been reported, including reduced blood loss, surgical time and surgical complications, and improved outcomes. However, the technical details of both embolization and surgical procedures, and lesions widely vary. Thus, the actual benefits of preoperative embolization have not been clarified by prospective randomized studies. Procedure-related complications due to embolization developed in 3%-12% in previous studies. For parasellar lesions, both surgical resection and embolization have a higher risk of complication than for lesions at other locations because of the complicated neurovascular anatomy in the parasellar area. Therefore, close attention should be paid to the detailed vascular anatomy, embolic material, and related information for embolization and resection in individual cases to improve patient outcomes.

An Overview of Managements in Meningiomas

Meningioma is the most frequent primary tumor of the central nervous system. Important advances have been achieved in the treatment of meningioma in recent decades. Although most meningiomas are benign and have a good prognosis after surgery, clinicians often face challenges when the morphology of the tumor is complicated or the tumor is close to vital brain structures. At present, the longstanding treatment strategies of meningioma are mainly surgery and radiotherapy. The effectiveness of systemic therapy, such as chemotherapy or targeted therapy, has not been confirmed by big data series, and some clinical trials are still in progress. In this review, we summarize current treatment strategies and future research directions for meningiomas.

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.