Controversies in the role of preoperative embolization in meningioma management

Pioneering artificial intelligence-based real time assistance for intracranial liquid embolization in humans: an initial experience

BACKGROUND

Liquid embolization in neuroendovascular procedures carries the risk of embolizing an inappropriate vessel. Operators must pay close attention to multiple vessels during the procedure to avoid ischemic complications. We report our experience with real time artificial intelligence (AI) assisted liquid embolization and evaluate its performance.

METHODS

An AI-based system (Neuro-Vascular Assist, iMed technologies, Tokyo, Japan) was used in eight endovascular liquid embolization procedures in two institutions. The software automatically detects liquid embolic agent on biplane fluoroscopy images in real time and notifies operators when the agent reaches a predefined area. Safety, efficacy, and accuracy of the notifications were evaluated using recorded videos.

RESULTS

Onyx or n-butyl-2-cyanoacrylate (NBCA) was used in the treatment of arteriovenous malformation, dural arteriovenous fistula, meningioma, and chronic subdural hematoma. The mean number of true positive and false negative notifications per case was 31.8 and 2.8, respectively. No false positive notifications occurred. The precision and recall of the notifications were 100% and 92.0%, respectively. In 28.3% of the true positive notifications, the operator immediately paused agent injection after receiving the notification, which demonstrates the potential effectiveness of the AI-based system. No adverse events were associated with the notifications.

CONCLUSIONS

To the best of our knowledge, this is the first report of real time AI assistance with liquid embolization procedures in humans. The system demonstrated high notification accuracy, safety, and potential clinical usefulness in liquid embolization procedures. Further research is warranted to validate its impact on clinical outcomes. AI-based real time surgical support has the potential to advance neuroendovascular treatment.

Longitudinal Imaging of Tumor Perfusion After Preoperative Endovascular Embolization in Meningiomas: Surgical Time Window Selecting, Clinical Consideration, and Outcomes

OBJECTIVE

To quantitatively investigate the longitudinal computed tomography perfusion (CTP) imaging in meningiomas preoperatively embolized using microcatheters.

METHODS

This retrospective monocentric study included 27 patients with symptomatic supratentorial meningiomas. Quantitative computed tomography perfusion (CTP) images before and postembolization were evaluated and correlated with angiographic, immunohistochemical, and clinical data.

RESULTS

The mean age of the patients was 45 ± 18 years, with a female-to-male ratio of 1.45:1. After embolization, both the embolized (Eb) and unembolized (UEb) regions showed hypoperfusion. A steady state was achieved on days 4-6 postembolization, during which differences in regional cerebral blood volume (rCBV) (Eb 0.5 ± 0.3 ml/100 mg, UEb 3.3 ± 1.4 ml/100 mg; P < 0.05), and mean transit time (MTT) (Eb 3.5 ± 1.8 s, UEb 3.1 ± 0.4 s) were observed. The cerebral blood flow (rCBF) and time to the peak (TTP) exhibited opposite patterns between Eb and UEb. A steady state was reached in rCBF (Eb 1.7 ± 1.2 ml/100 g/min, UEb 30 ± 5.4 ml/100 g/min; P < 0.01), and TTP (Eb 5 ± 4.8 s, UEb 1.8 ± 1.5 s; P < 0.01) within 4 to 6 days. Estimated blood loss (EBL) showed significant association with the surgical time interval among the 3 groups (P < 0.05). Tissue necrosis predominated over 7 days postembolization, indicating a correlation with the devascularization process. The overall incidence of postembolized headache, seizures, extremity weakness/paralysis, and postoperational headache was 11.1%, 7.4%, 3.7%; and 7.4%, respectively. All symptoms resolved by the last follow-up (3 months).

CONCLUSION

Preoperative embolization of meningiomas using N-butyl cyanoacrylate effectively induced significant and sustained tissue transformation and decreased estimated blood loss (EBL) over 7 days. Hemodynamic fluctuations tended to stabilize within 4 to 6 days.

Scalp necrosis following preoperative endovascular embolisation of the superficial temporal artery for meningioma

A woman in her late 50s with a left frontal lobe convexity meningioma underwent an elective endovascular embolisation of the left middle meningeal artery and distal branches of the left superficial temporal artery prior to surgical resection of the tumour. On postoperative day 46, she developed scalp necrosis, leading to poor wound healing requiring wound debridement and a complex plastic surgery reconstruction with a rotational flap. Endovascular embolisation of vascular tumours prior to surgical resection does not come without risks. The lack of consistency in the literature regarding indication, technique and outcomes makes it difficult to define the exact role of preoperative meningioma embolisation.

Embolic Material Migration as the Predominant Contributing Factor to Prognostic Deterioration Following Combined Tumor Resection and Preoperative Embolization

Introduction Preoperative embolization can potentially facilitate surgical resection of challenging tumors in the intracranial and facial regions; however, its clinical efficacy remains controversial, mainly due to potential morbidity risks. We explored negative factors of the combined treatment of preoperative embolization and tumor resection that affect neurological prognosis. Method This retrospective study used clinical data from 132 consecutive tumors that underwent combined treatment at multiple facilities between January 2016 and May 2021. Basic patient information, tumor characteristics, and treatment details were assessed to identify predictors of deterioration as measured using the modified Rankin scale (mRS) score at three months post-treatment. Results Among the 126 eligible combined treatments, a deterioration in the postoperative mRS score was observed in 19/126 (15.1%). Complications related to embolization and tumor resection occurred in 8/126 (6.3%) and 19/125 (15.2%) of procedures, respectively. Multivariate analyses indicated significant associations between migration of embolic material (adjusted odds ratio 13.80; 95% confidence interval 1.25-152.52; p=0.03), elevated intraoperative blood loss (p=0.04), and deterioration of postoperative mRS score. Embolic material migration was identified as the primary prognostic factor for the deterioration of score. An analysis of 192 procedures, excluding those that exclusively used coils, identified embolization targeting the accessory meningeal artery (p=0.046) and the third segment of the internal maxillary artery (p=0.03) as a risk factor for embolic material migration. Conclusions Embolic material migration is the predominant factor associated with declining neurological outcome that persists into the chronic phase after combined treatment. Given that preoperative embolization is a supplementary treatment option, a thorough understanding of vascular anatomy and striving safe procedure are critical.

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.

Surgical complications and recurrence factors for asymptomatic meningiomas: a single-center retrospective study

PURPOSE

Observation is the first management option in asymptomatic meningiomas, but when an enlargement or mass effect is observed, surgery is indicated. This study is aimed at exploring risk factors for complications and recurrence after surgery for asymptomatic meningioma. We also examined the impact of preoperative tumor embolization, which is considered controversial.

METHODS

We retrospectively reviewed 109 patients with primary asymptomatic meningiomas surgically treated at our institute between April 2007 and March 2021. Patients who only had headaches as a nonspecific complaint were included in the asymptomatic group. Complications, time to recurrence, and Glasgow Outcome Scale (GOS) score were the endpoints of the study. Risk factors for complications and recurrence were explored. Moreover, the effect of the resection on nonspecific headaches was also explored.

RESULTS

The permanent postoperative complication rate related to the surgical procedure was 1.8%. Of the total, 107 patients (98.2%) with asymptomatic meningiomas who were surgically treated achieved a GOS score of 5 1 year after the operation. Preoperative headache was present in 31 patients and improved postoperatively in 21 patients. Multivariate analysis using the Cox proportional hazard model showed that preoperative tumor embolization with > 80% resolution of tumor staining (p < 0.001) was negatively related to recurrence, whereas age (p = 0.046) and Simpson grade IV resection (p = 0.041) were positively related to recurrence.

CONCLUSION

Although surgery for asymptomatic meningiomas can, in many cases, be safe, it is not free of complications Thus, surgical intervention for asymptomatic meningiomas should be considered cautiously. However, more than half the patients with headaches showed improvement. Simpson grade IV resection cases should be assessed for recurrence, and preoperative tumor embolization might be effective in controlling recurrence.

Selective Angiographic Flat Detector Computer Tomography Blood Volume Imaging in Pre-Operative Vascular Mapping and Embolization of Hypervascular Intracranial Tumors-Preliminary Clinical Experience

Pre-operative embolization of hypervascular intracranial tumors can be performed to reduce bleeding complications during resection. Accurate vascular mapping of the tumor is necessary for both the correct indication setting for embolization and for the evaluation of the performed embolization. We prospectively examined the role of whole brain and selective parenchymal blood volume (PBV) flat detector computer tomography perfusion (FD CTP) imaging in pre-operative angiographic mapping and embolization of patients with hypervascular intracranial tumors. Whole brain FD CTP imaging with a contrast injection from the aortic root and selective contrast injection in the dural feeding arteries was performed in five patients referred for tumor resection. Regional relative PBV values were obtained pre- and post-embolization. Total tumor volumes with selective external carotid artery (ECA) supply volumes and post-embolization devascularized tumor volumes were determined as well. In all patients, including four females and one male, with a mean age of 54.2 years (range 44-64 years), the PBV scans were performed without adverse events. The average ECA supply was 54% (range 31.5-91%). The mean embolized tumor volume was 56.5% (range 25-94%). Relative PBV values decreased from 5.75 ± 1.55 before embolization to 2.43 ± 1.70 post-embolization. In one patient, embolization was not performed because of being considered not beneficial for the resection. Angiographic FD CTP imaging of the brain tumor allows 3D identification and quantification of individual tumor feeder arteries. Furthermore, the technique enables monitoring of the efficacy of pre-operative endovascular tumor embolization.

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.

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.

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.

Efficacy of endovascular intratumoral embolization for meningioma: assessment using dynamic susceptibility contrast-enhanced perfusion-weighted imaging

BACKGROUND

In preoperative embolization for intracranial meningioma, endovascular intratumoral embolization is considered to be more effective for the reduction of tumorous vascularity than proximal feeder occlusion. In this study, we aimed to reveal different efficacies for reducing tumor blood flow in meningiomas by comparing endovascular intratumoral embolization and proximal feeder occlusion using dynamic susceptibility contrast-enhanced perfusion-weighted imaging (DSC-PWI).

METHODS

28 consecutive patients were included. DSC-PWI was performed before and after embolization for intracranial meningiomas. Normalized tumor blood volume (nTBV) of voxels of interest of whole tumors were measured from the DSC-PWI data before and after embolization. ΔnTBV% was compared between the cases that received intratumoral embolization and proximal feeder occlusion.

RESULTS

ΔnTBV% in the intratumoral embolization group (42.4±29.8%) was higher than that of the proximal feeder occlusion group (15.3±14.3%, p=0.0039). We used three types of embolic materials and ΔnTBV% did not differ between treatments with or without the use of each material: 42.8±42.4% vs 28.7±20.1% for microspheres (p=0.12), 36.1±20.6% vs 28.1±41.1% for n-butyl cyanoacrylate (p=0.33), and 32.3±37.3% vs 34.1±19.0% for bare platinum coils (p=0.77).

CONCLUSIONS

The flow reduction effect of intratumoral embolization was superior to that of proximal feeder occlusion in preoperative embolization for intracranial meningioma in an assessment using DSC-PWI.

Preoperative obliteration of choroidal arteries in the treatment of large hypervascular tumors in the lateral ventricle

Background

Removal of large hypervascular tumors in the lateral ventricle still poses a surgical challenge. These tumors are usually fed from choroidal arteries, and vascular control is typically performed late during the removal. We aimed to evaluate the clinical efficacy of our strategy for persistent preoperative obliteration of feeders from the choroidal arteries to manage large hypervascular tumors in the lateral ventricle.

Methods

We retrospectively analyzed six patients with hypervascular tumors in the lateral ventricle. We first attempted to obstruct feeders using endovascular treatment, and, if unavailable, performed initial microsurgical occlusion through the temporal horn for the staged tumor removal.

Results

In all patients, feeder obliteration was successfully performed; the anterior choroidal arteries were occluded by the endovascular treatment and microsurgical occlusion in one and five patients, respectively, while the lateral posterior choroidal arteries were occluded via endovascular treatment in four patients. No patients had permanent symptoms due to feeder obliteration, and tumor devascularization was achieved at the mean rate of 69.9%. During the tumor removal, the mean blood loss volume was 253 ml. No postoperative hemorrhage had occurred, and all patients scored ≤ 2 on the modified Rankin Scale at six months post-removal.

Conclusions

Although further studies are warranted, persistent feeder obliteration of choroidal arteries could be an effective treatment strategy against large hypervascular tumors in the lateral ventricle.

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.

Clinicopathologic Factors Associated with Tumor Necrosis after Preoperative Embolization of Meningiomas

Objective

Preoperative embolization of meningiomas induces necrosis prior to surgery and facilitates resection. Lack of contrast enhancement on postembolization MRI correlates with pathological findings of necrosis and can be used to assess embolization efficacy. This study aimed to examine clinicopathologic factors associated with tumor necrosis after embolization.

Methods

A total of 119 patients with intracranial meningioma who underwent 145 surgical resections between 2010 and 2019 at our institute were reviewed. Inclusion criteria for the study were preoperative embolization with trisacryl gelatin microspheres (Embosphere) or absorbable gelatine sponge (Gelfoam). Postembolization Gd-enhanced T1-weighted and angiographic imaging, and histopathologic examination results were reviewed to evaluate the effectiveness of embolization.

Results

In all, 66 patients satisfied the inclusion criteria. In total, 36 patients were embolized with Embosphere and 30 patients were embolized with Gelfoam. Patients embolized with Embosphere had a significantly higher necrosis rate (NR) than patients with Gelfoam (21% vs. 7.1%, P <0.01). The 36 Embosphere patients were analyzed regarding clinicopathologic factors associated with NR. Tumors in 12 patients were located in the parasagittal/falx region; these patients had a significantly lower NR compared with tumors in other locations (10.6% vs. 26.2%, P = 0.016). In all, 13 patients had feeders arising from only the middle meningeal artery (MMA), which was associated with a significantly higher NR (29.3% vs. 14.4%, P = 0.015). In total, 11 patients had meningeal feeders arising from internal carotid artery (ICA), which was associated with a significantly lower NR (9.0% vs. 26.3%, P <0.01).

Conclusion

This study showed embolization agent, tumor location, and blood supply were important factors predicting necrosis after preoperative embolization.

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.

ICAR: endoscopic skull-base surgery

BACKGROUND

Endoscopic skull-base surgery (ESBS) is employed in the management of diverse skull-base pathologies. Paralleling the increased utilization of ESBS, the literature in this field has expanded rapidly. However, the rarity of these diseases, the inherent challenges of surgical studies, and the continued learning curve in ESBS have resulted in significant variability in the quality of the literature. To consolidate and critically appraise the available literature, experts in skull-base surgery have produced the International Consensus Statement on Endoscopic Skull-Base Surgery (ICAR:ESBS).

METHODS

Using previously described methodology, topics spanning the breadth of ESBS were identified and assigned a literature review, evidence-based review or evidence-based review with recommendations format. Subsequently, each topic was written and then reviewed by skull-base surgeons in both neurosurgery and otolaryngology. Following this iterative review process, the ICAR:ESBS document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:ESBS document addresses the role of ESBS in primary cerebrospinal fluid (CSF) rhinorrhea, intradural tumors, benign skull-base and orbital pathology, sinonasal malignancies, and clival lesions. Additionally, specific challenges in ESBS including endoscopic reconstruction and complication management were evaluated.

CONCLUSION

A critical review of the literature in ESBS demonstrates at least the equivalency of ESBS with alternative approaches in pathologies such as CSF rhinorrhea and pituitary adenoma as well as improved reconstructive techniques in reducing CSF leaks. Evidence-based recommendations are limited in other pathologies and these significant knowledge gaps call upon the skull-base community to embrace these opportunities and collaboratively address these shortcomings.

Modern day imaging of meningiomas

Meningiomas are the most common primary tumors of the central nervous system and as such they are often encountered at neuroimaging. Fortunately, meningiomas are readily diagnosed with anatomic computed tomography and magnetic resonance imaging. While conventional imaging is the mainstay for initial diagnosis and delineating tumor for treatment planning and posttreatment follow-up, the last couple of decades have given rise to advanced physiologic and metabolic imaging techniques that serve as powerful tools in the management of meningioma. These modern approaches are allowing imaging to expand its utility to include extraction of biologic and potentially prognostic information that will ultimately improve care for meningioma patients.

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.

Can we predict intraoperative blood loss in meningioma patients? Application of dynamic susceptibility contrast-enhanced magnetic resonance imaging

PURPOSE

To evaluate the potential of quantitative dynamic susceptibility contrast (DSC) perfusion MR imaging parameters as imaging biomarkers for predicting intraoperative blood loss in meningioma.

METHODS

Fifty-one non-embolized meningioma patients who had undergone preoperative DSC perfusion MR imaging were retrospectively included. The corrected relative cerebral blood volume (rCBV) and leakage coefficient (K₂) of the entire enhanced tumor were obtained using leakage correction. Tumor volume, location, grade, and other clinical variables, were also analyzed. To investigate the vascularity and vascular permeability of meningiomas, and their correlation with predicting estimated blood loss (EBL) using preoperative DSC perfusion MR imaging, the authors proposed an index reflecting the inherent tendency of meningiomas to bleed after controlling volume (i.e., EBL/cm³). Simple regression was performed to identify predictors of EBL/cm³; subsequently, the relevant variables included in the stepwise multiple linear regression.

RESULTS

On univariate analysis, EBL/cm³ was correlated with rCBV (r=0.677; P<0.001), K₂ (r=0.294; P=0.036), and tumor volume (r=-0.312, P=0.026). EBL/cm³ was not correlated with age (P=0.873), sex (P=0.404), tumor location (P=0.327), or histological grade (P=0.230). On multiple linear regression, rCBV (β=0.663 [0.463-0.864], B=1.293 [0.903-1.684; P<0.001) and K₂ (β=0.260 [0.060-0.460], B=2.277 [0.523-4.031], P=0.012), were the only independent predictors of EBL/cm³.

CONCLUSION

The rCBV and K₂ derived from DSC perfusion MR imaging in meningiomas may serve as feasible tools for clinicians to predict intraoperative blood loss and facilitate surgical planning.

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.

Non-invasive qualitative and semiquantitative presurgical investigation of the feeding vasculature to intracranial meningiomas using superselective arterial spin labeling

BACKGROUND

Intracranial meningiomas may be amenable to presurgical embolization to reduce bleeding complications. Detailed information usually obtained by digital subtraction angiography (DSA) on the contribution of blood supply from internal and external carotid artery branches is required to prevent non-target embolization and is helpful for pre-surgical planning.

PURPOSE

To investigate the contribution of the feeding vasculature to intracranial meningiomas with superselective arterial spin labelling (sASL) as an alternative to DSA.

MATERIAL AND METHODS

Consecutive patients presenting for meningioma resection were prospectively included. sASL perfusion images acquired on a clinical 3T MRI scanner were independently rated by two readers. Contribution of the external carotid artery (ECA), internal carotid artery (ICA) and vertebral/basilar artery (VA/BA) was rated as none, <50% or >50%. Correlation of sASL was performed in two patients undergoing DSA.

RESULTS

32 patients (61 ± 13 years) harboring 42 meningiomas could be included. sASL was technically successful in all patients. 19 meningiomas had ICA dominant supply, 19 had ECA dominant supply. One meningioma had mixed supply and in three meningiomas a perfusion signal could not be detected. While exclusive unilateral ECA supply was common (n = 14) and exclusive unilateral ICA was rare (n = 4), mixed supply from multiple vessels (n = 20) was a frequent finding. Interrater agreement was substantial (κ = 0.73). Agreement with DSA was perfect within our predefined categories.

CONCLUSION

sASL is able to identify the presence and extent of the feeding vasculature in intracranial meningiomas.

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.

Post-operative cardiovascular complications and time to recurrence in meningioma patients treated with versus without pre-operative embolization: a retrospective cohort study of 741 patients

PURPOSE

Preoperative embolization of radiographically suspected meningiomas is often performed to facilitate tumor resection. Its effects on the subsequent disease course of meningioma patients have not been studied in detail and randomized trials are lacking. The purpose of this study was to explore associations of preoperative meningioma embolization with postoperative outcome.

PATIENTS AND METHODS

Patients undergoing resection of an intracranial meningioma at the University Hospital Zurich 2000-2013 (N = 741) were reviewed for the inclusion of pre-operative embolization in the management strategy. Annotations included demographics, radiographic, surgical, histological and hematological parameters, cardiovascular risk factors, pre- and postoperative neurological function and gene methylation-based classification. Binary regression and Cox proportional hazards models were applied to determine factors associated with outcome.

RESULTS

Pre-operative embolization was performed in 337 patients (42%). Cardiovascular events after surgery comprised mostly deep vein thrombosis (N = 39) and pulmonary embolisms (N = 64). On multivariate analyses of post-operative cardiovascular adverse events controlling for established risk factors, there were associations with embolization (OR 2.38, 95% CI 1.37-4.00), and with female gender (OR 2.18, 95% CI 1.17-4.08). Recurrence-free survival (RFS) of embolized patients was less favorable among patients with WHO grade II or grade III meningiomas (median RFS: 4.3 vs. 7.0 years, P = 0.029) or in patients with intermediate or malignant gene methylation subtype meningiomas (median RFS: 2.0 vs. 8.2 years, P = 0.005).

CONCLUSION

Pre-operative meningioma embolization may cause adverse outcomes. Randomized trials to determine benefit-risk ratios are warranted to clarify the role of pre-operative embolization for the treatment of meningioma patients.

The evolution of cranial meningioma surgery-a single-center 25-year experience

BACKGROUND

There have been major developments in diagnostic and surgical and non-surgical techniques used in the management of meningiomas over last three decades. We set out to describe these changes in a systematic manner.

METHOD

Clinical and radiological data, surgical procedures, complications, and outcome of 817 patients who underwent surgery for primarily diagnosed meningioma between 1991 and 2015 were investigated.

RESULTS

Median age at diagnosis increased significantly from 56 to 59 years (p = .042), while tumor location and preoperative Karnofsky performance status did not change during the observation period. Availability of preoperative MRI increased, and rates of angiography and tumor embolization decreased (p < .001, each). Median duration of total, pre-, and postoperative stay was 13, 2, and 9 days, respectively, and decreased between 1991 and 2015 (p < .001, each). Median incision-suture time varied annually (p < .001) but without becoming clearly longer or shorter during the entire observation period. The use of intraoperative neuronavigation and neuromonitoring increased, while the rates of Simpson grade I and III surgeries decreased (p < .001). Rates of postoperative hemorrhage (p = .997), hydrocephalus (p = .632), and wound infection (p = .126) did not change, while the frequency of early postoperative neurological deficits decreased from 21% between 1991 and 1995 to 13% between 2011 and 2015 (p = .003). During the same time, the rate of surgeries for postoperative cerebrospinal fluid leakage slightly increased from 2 to 3% (p = .049). Within a median follow-up of 62 months, progression was observed in 114 individuals (14%). Progression-free interval did not significantly change during observation period (p > .05). Multivariate analyses confirmed the lack of correlation between year of surgery and tumor relapse (HR: 1.1, p > .05).

CONCLUSIONS

Preoperative diagnosis and surgery of meningiomas have been substantially evolved. Although early neurological outcome has improved, long-term prognosis remains unchanged.

Safety and Efficacy of Preoperative Embolization in Patients with Meningioma

Preoperative embolization for intracranial meningioma has remained controversial for several decades. In this study, we retrospectively reviewed our experience of embolization using particulate embolic material and coil to clarify the therapeutic efficacy, safety, and risk of complication. Methods  We reviewed 69 patients who underwent embolization with particulate embolic material followed by surgical resection. An additional 6 procedures were included for patients in whom recurrence was treated, for a total of 75 procedures of preoperative embolization. We analyzed the following clinical data: age, sex, tumor size pathology, complications related to embolization, and surgeon's opinion on the intraoperative ease of debulking and blood transfusion. Embolization was performed mainly from the branches of the external carotid artery. Results  No allogenic blood transfusions were needed for any patients. The surgeon had the opinion that whitening and softening of the tumor allowed for easy debulking during decompression of the tumor in most of the patients. Hemorrhagic complications were seen in two patients after embolization. Emergency tumor removal was performed in both of those patients, and they were recovered well after surgery. Transient cranial nerve palsy was seen in one patient. One ischemic complication and one allergic complication occurred. Conclusion  Preoperative embolization could give us an advantage in surgery for meningioma. The procedure reduces intraoperative blood loss and operating time by softening the tumor consistency. However, we must pay attention to the possibility of embolic complications and keep the preparation of emergency craniotomy, particularly in patients with large meningiomas.

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.

Impact of preoperative endovascular embolization on immediate meningioma resection outcomes

OBJECTIVE

Preoperative embolization of meningiomas can facilitate their resection when they are difficult to remove. The optimal use and timing of such a procedure remains controversial given the risk of embolization-linked morbidity in select clinical settings. In this work, the authors used a large national database to study the impact of immediate preoperative embolization on the immediate outcomes of meningioma resection.

METHODS

Meningioma patients who had undergone elective resection were identified in the National (Nationwide) Inpatient Sample (NIS) for the period 2002–2014. Patients who had undergone preoperative embolization were propensity score matched to those who had not, adjusting for patient and hospital characteristics. Associations between preoperative embolization and morbidity, mortality, and nonroutine discharge were investigated.

RESULTS

Overall, 27,008 admissions met the inclusion criteria, and 633 patients (2.34%) had undergone preoperative embolization and 26,375 (97.66%) had not. The embolization group was younger (55.17 vs 57.69 years, p < 0.001) with a lower proportion of females (63.5% vs 69.1%, p = 0.003), higher Charlson Comorbidity Index (p = 0.002), and higher disease severity (p < 0.001). Propensity score matching retained 413 embolization and 413 nonembolization patients. In the matched cohort, preoperative embolization was associated with increased rates of cerebral edema (25.2% vs 17.7%, p = 0.009), posthemorrhagic anemia or transfusion (21.8% vs 13.8%, p = 0.003), and nonroutine discharge (42.8% vs 35.7%, p = 0.039). There was no difference in mortality (≤ 2.4% vs ≤ 2.4%, p = 0.82). Among the embolization patients, the mean interval from embolization to resection was 1.49 days. On multivariate analysis, a longer interval was significantly associated with nonroutine discharge (OR 1.33, p = 0.004) but not with complications or mortality.

CONCLUSIONS

Relative to meningioma patients who do not undergo preoperative embolization in the same admission, those who do have higher rates of cerebral edema and nonroutine discharge but not higher rates of stroke or death. Thus, meningiomas requiring preoperative embolization represent a distinct clinical entity that requires prolonged, more complex care. Further, among embolization patients, the timing of resection did not affect the risk of in-hospital complications, suggesting that the timing of surgery can be determined according to surgeon discretion.

Preoperative Embolization of Meningiomas: Differences in Surgical Operability and Histopathologic Changes Between Embosphere and N-butyl 2-cyanoacrylate

OBJECTIVE

This study aimed to examine whether there is a difference in the difficulty of extirpation after use of Embosphere versus n-butyl 2-cyanoacrylate (NBCA) for the embolization of meningiomas.

METHODS

Study subjects were 20 patients with meningioma who underwent embolization using either NBCA or Embosphere from April 2012 to December 2016. The difficulty of extirpation was compared and assessed in terms of objective indices, such as operative duration, perioperative bleeding, and Simpson grade, and in terms of subjective indices such as "impression on operative field" and "hardness of tumors" that the surgeon assessed using 3-point scales (dry, moderate, bloody, and soft, moderate, hard, respectively). Pathologic findings, including ischemia, necrosis, and inflammatory changes, were assessed.

RESULTS

No significant differences were found between the 2 groups regarding the mean values of operative duration (P = 0.27), perioperative bleeding (P = 0.23), and Simpson grade (P = 0.39). On the other hand, there was a significant difference with respect to the "impression on operative field" and "hardness of tumors," with reports of dry (54%; P = 0.034) and soft (81%; P = 0.0001), respectively, in the Embosphere group exceeding those of the NBCA group. The pathologic findings showed that although ischemic change (P = 0.43) and necrosis (P = 0.79) were observed in both groups, perivascular inflammation was observed only in the NBCA group (P = 0.006).

CONCLUSIONS

No relative merits were found regarding objective indices, whereas the Embosphere group had superior "ease of extirpation" as reported by the surgeon.

Tumor Volume Decrease via Feeder Occlusion for Treating a Large, Firm Trigone Meningioma

Trigone meningiomas are considered a surgical challenge, as they tend to be considerably large and hypervascularized at the time of presentation. We experienced a case of a large and very hard trigone meningioma that was effectively treated using initial microsurgical feeder occlusion followed by surgery in stages. A 19-year-old woman who presented with loss of consciousness was referred to our hospital for surgical treatment of a brain tumor. Radiological findings were compatible with a left ventricular trigone meningioma extending laterally in proximity to the Sylvian fissure. At initial surgery using the transsylvian approach, main feeders originating from the anterior and lateral posterior choroidal arteries were occluded at the inferior horn; however, only a small section of the tumor could initially be removed because of its firmness. Over time, feeder occlusion resulted in tumor necrosis and a 20% decrease in its diameter; the mass effect was alleviated within 1 year. The residual meningioma was then totally excised in staged surgical procedures after resection became more feasible owing to ischemia-induced partial softening of the tumor. When a trigone meningioma is large and very hard, initial microsurgical feeder occlusion in the inferior horn can be a safe and effective option, and can lead to necrosis, volume decrease, and partial softening of the residual tumor to allow for its staged surgical excision.

Surgical Management of Anterolateral and Posteromedial Incisural Tentorial Meningioma

BACKGROUND

Tentorial meningiomas are a broad and consistent category of tumors but their definition is still unclear and their classification uncertain.

OBJECTIVE

To report the clinical and surgical characteristics of tentorial hiatus meningiomas based on a revised classification of tentorial meningiomas.

METHODS

We reviewed the records of 14 patients who had undergone microsurgical removal of incisural tentorial meningioma. Two tumor subgroups, anterolateral (AL) and posteromedial (PM), were distinguished according to their site of attachment: the middle third and the posterior third of the tentorial free margin, respectively. Clinical presentation, radiological findings, surgical approaches, extent of resection, and outcome were compared.

RESULTS

The 2 subgroups differed by tumor size (larger in PM), incidence of the direction of growth (infratentorial in PM), and hydrocephalus (only in PM), as well as by some clinical aspects. Surgical approach depended on tumor location: lateral (pterional, subtemporal, and retromastoid) for AL lesions; medial (occipital or supracerebellar infratentorial) for PM lesions. Total removal (Simpson grade I-II) was performed in 64% of cases and complications occurred in 14%. Stereotactic radiosurgery was performed in cases of incomplete resection. At a mean follow-up of 104.5 mo, clinical improvement with low recurrence (9%) was achieved.

CONCLUSION

Reallocation of tentorial edge meningiomas is the premise to compare treatment and further improve the approach case-by-case. In spite of their deep site, good outcomes can be achieved in both AL and PM tentorial meningiomas. Also of note is the indolent behavior of residual tumor.

Improving Forward Infusion Pressure during Brain Tumor Embolization with the Double Catheter and Coil Technique

Endovascular embolization or embosurgery of brain tumors can be used to reduce neoplasm vascularity prior to surgical resection. Two challenges with embosurgery relate to insufficient perfusion pressure into the tumor and inadvertent escape of infused agents into parenchymal branches of the adjacent brain. This report describes a multi-catheter and coil technique to improve tumor perfusion and prevent reflux into normal branches.

Preoperative Embolization for Skull Base Meningiomas

The results of preoperative embolization for skull base meningiomas were retrospectively evaluated to confirm the efficacy of this procedure. Skull base meningiomas that were treated with preoperative embolization were evaluated in 20 patients. The occluded arteries, embolic materials, treatment time, excision rate, neurologic manifestations, and complications were analyzed. The embolic material was 80% liquid, 30% coils, and 15% particles. The surgery was normally completed within 3 to 5 hours. Blood loss was normally approximately 250 mL, excluding four patients having the following conditions: malignant meningioma, a large tumor located on the medial side of the sphenoidal ridge, the petroclival tumor, and infiltrated tumor into the sigmoid sinus. The mean excision rate was 90%, achieving a Simpson grade III, but 10% were graded as Simpson grade IV. No permanent complications due to the preoperative embolization occurred. No neurologic symptoms occurred after excision. Current cerebral endovascular treatment is sophisticated, and the complication rate has markedly decreased. Although it was impossible to compare directly with or without operative embolization, preoperative embolization should be actively used as part of the treatment for this benign tumor, with better understanding of dangerous anastomosis.

Extent of T1+C Intensity Is a Predictor of Blood Loss in Resection of Meningioma

INTRODUCTION

Surgery for meningioma is associated with significant blood loss. Preoperative embolization has been associated with reduction of blood loss and has been noted to decrease intensity on T1 + contrast sequences. We investigate potential relationships between blood loss and the extent of T1 + contrast intensity.

METHODS

Forty-two patients who underwent surgical resection of intracranial meningioma were retrospectively reviewed from August 2009 to May 2016. Clinical data were extracted (age, gender, location of meningioma, grade of meningioma, need for blood transfusion during surgery, preoperative and postoperative hematocrit level, estimated blood loss [EBL], and duration of surgery). Using OsiriX MD, the tumor volume, sinus involvement, peritumoral edema, extent of resection, and T1 index (average T1+C intensity across the tumor normalized to value at basilar artery) were assessed.

RESULTS

With EBL, univariate analysis for gender, tumor volume, and T1 index showed correlations with P value <0.1. A logistic regression to predict EBL <300 mL and ≥300 mL using the 3 variables yielded T1 index (odds ratio [OR], 31.22; 95% confidence interval [CI], 1.14-855.65), gender (OR, 0.17; 95% CI, 0.03-0.96), and tumor volume (OR, 1.05; 95% CI, 1.00-1.10) as significant predictors (all P < 0.05). With duration for surgery, gender, tumor volume, need for blood transfusion, and preoperative hematocrit exhibited P value <0.05; multivariate analysis did not show a significant model.

CONCLUSIONS

Along with gender and tumor volume, extent of T1+C intensity is also an independent predictor of EBL. This finding may be helpful for surgical management of meningioma.

Endovascular prelude for delicate meningeoma operation: A case report

Introduction: Embolization prior to surgery can make tumor resection less complicated by reducing blood loss during surgery and shortening the time of the operation. Case report: In this paper, we presented a case of a sixty-three-year-old woman who was admitted to the Clinic of Neurosurgery, Clinical Center Niš, Serbia, at November 2016, after she underwent a CT brain scan that showed a large tumor of the left cerebellopontile angle. Digital subtraction angiography presented a large, highly vascularized tumor lesion that compressed the brain stem. The patient underwent endovascular procedure, and complete embolization of the tumor vessels was established. The radiologist delivered embolization material via the left ascending pharyngeal artery. In the next 24 hours, an operation was performed i.e. radical extirpation surgery (Simpson grade I). Postoperatively, the patient's GCS was 15, with no new neurological deficit. Postoperative brain CT scan showed neither rest tumor nor blood clot inside the tumor bed. Pathohistological finding revealed atypical meningioma grade II. Conclusion: Despite some clinicians' dilemma considering the utility of preoperative embolization of meningioma vessels, we believe that a team of educated and dedicated radiologist and neurosurgeon could achieve great results in resection of large and inaccessible cranial tumors.

New Software for Preoperative Diagnostics of Meningeal Tumor Histologic Types

OBJECTIVE

Meningeal tumors are neoplasms with different histologic manifestations of both benign and malignant types that determine the prognosis of tumor recurrence and its consistency. The risk of surgical treatment depends on the location, size, and consistency of the tumor. Magnetic resonance imaging (MRI) sequences can be used to identify the features of tumors, but these MRI characteristics are not well understood. The present study describes an advanced mathematical algorithm to analyze MRI data and distinguish histologic types of meningeal tumors before surgery.

METHODS

Forty-eight patients underwent surgical removal of meningeal brain tumor. All patients had preoperative MRI with a 1.5-T scanner. One radiologist and 2 neurosurgeons evaluated MRI histogram peaks of the whole tumor volume using the advanced computer algorithm.

RESULTS

Three specialists received the following mean value of histogram peaks: 15.99 ± 0.23 (± standard error of the mean [SEM]) for meningoteliomatous meningiomas; 21.24 ± 0.3 (±SEM) for fibroplastic meningiomas; 19.0 ± 0.28 (±SEM) for transitional meningiomas; 10.7 ± 0.27 (±SEM) for anatypical, anaplastic meningiomas, 11.03 ± 0.51 (±SEM) for primary intracranial fibrosarcomas and 25.72 ± 0.29 (±SEM) for meningeal hemangiopericytomas. A one-way analysis of variance test proved the difference between group means: F = 70.138, P < 0.01. The Tukey test and the Games-Howell test indicated that the difference between the tumor groups was significant. Mean deviation in agreement index between specialists was 0.98 ± 0.007 (±SEM).

CONCLUSIONS

The advanced algorithm proved high specificity, sensitivity, and interoperator repeatability.

Safety and efficacy of medium-sized particle embolisation for skull-base meningioma

AIM

To determine the effectiveness and safety of preoperative tumour embolisation for skull-base meningiomas via external carotid artery (ECA) feeders using medium-sized (150-250 μm) polyvinyl alcohol (PVA) particles.

MATERIALS AND METHODS

This study included 114 consecutive patients with skull-base meningiomas who underwent preoperative tumour embolisation using medium-sized PVA particles from January 2004 to December 2013. Tumours were categorised according to feeding artery as follows: type 1, tumour staining at ECA angiography only; type 2, tumour staining at both the ECA and internal carotid artery (ICA) angiography; or type 3, little or no tumour staining at ECA angiography. The effectiveness was based on the percent reduction in the enhanced area: >75% was considered effective, 25-75% was considered partially effective, and <25% was considered ineffective.

RESULTS

Tumour embolisation was performed in patients with dominant feeding vessels originating from the ECA. Procedural-related complications occurred in two (1.8%) patients. Post-procedural MRI images were available for 51 patients, which revealed effective embolisation in only 13 (25.5%) patients. Identification of an ICA feeding vessel was associated with ineffective embolisation (p=0.011). Effective embolisation was associated with low estimated blood loss during surgery.

CONCLUSION

ECA embolisation using medium-sized PVA is ineffective in patients in whom a definitive ICA feeding vessel was identified, even if preprocedural angiography showed that the dominant feeder originated from the ECA. When the risks of surgical morbidity and mortality are expected to be high, ICA feeder embolisation should also be considered.

Preoperative endovascular embolization of meningiomas: update on therapeutic options

In this review paper the authors analyze new therapeutic options for the embolization of meningiomas, as well as the future of meningioma treatment through recent relevant cohorts and articles. They investigate various embolic materials, types of meningiomas amenable to embolization, imaging techniques, and potential imaging biomarkers that could aid in the delivery of embolic materials. They also analyze perfusion status, complications, and new technical aspects of endovascular preoperative embolization of meningiomas. A literature search was performed in PubMed using the terms "meningioma" and "embolization" to investigate recent therapeutic options involving embolization in the treatment of meningioma. The authors looked at various cohorts, complications, materials, and timings of meningioma treatment. Liquid embolic materials are preferable to particle agents because particle embolization carries a higher risk of hemorrhage. Liquid agents maximize the effect of devascularization because of deeper penetration into the trunk and distal tumor vessels. The 3 main imaging techniques, MRI, CT, and angiography, can all be used in a complementary fashion to aid in analyzing and treating meningiomas. Intraarterial perfusion MRI and a new imaging modality for identifying biomarkers, susceptibility-weighted principles of echo shifting with a train of observations (SW-PRESTO), can relay information about perfusion status and degrees of ischemia in embolized meningiomas, and they could be very useful in the realm of therapeutics with embolic material delivery. Direct puncture is yet another therapeutic technique that would allow for more accurate embolization and less blood loss during resection.