Preoperative superselective embolization of skull-base meningiomas: indications and limitations

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.

Advances in Imaging Modalities for Pediatric Brain and Spinal Cord Tumors

BACKGROUND

Neuroimaging has evolved from anatomical imaging toward a multi-modality comprehensive anatomical and functional imaging in the past decades, important functional data like perfusion-weighted imaging, permeability imaging, diffusion-weighted imaging (DWI), and diffusion tensor imaging (DTI), tractography, metabolic imaging, connectomics, event-related functional imaging, resting state functional imaging, and much more is now being offered.

SUMMARY

Precision diagnostics has proven to be essential for precision treatment. Many minimal invasive techniques have been developed, taking advantage of digital subtraction angiography and interventional neuroradiology. Furthermore, intraoperative CT and/or MRI and more recently MR-guided focused ultrasound have complemented the diagnostic and therapeutic armamentarium.

KEY MESSAGES

In the current manuscript, we discuss standard imaging sequences including advanced techniques like DWI, DTI, susceptibility-weighted imaging, and 1H magnetic resonance spectroscopy, various perfusion weighted imaging approaches including arterial spin labeling, dynamic contrast enhanced imaging, and dynamic susceptibility contrast imaging. Pre-, intra, and postoperative surgical imaging including visualize imaging will be discussed. The value of connectomics will be presented for its value in neuro-oncology. Minimal invasive therapeutic possibilities of interventional neuroradiology and image-guided laser ablation and MR-guided high-intensity-focused ultrasound will be presented for treatment of pediatric brain and spinal cord tumors. Finally, a comprehensive review of spinal cord tumors and matching neuropathology has been included.

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.

Pediatric age, posterior fossa meningioma

Meningiomas are benign, slow-growing tumors originating from arachnoid gap cells. They constitute 15%-20% of all intracranial tumors in adults and 04%-4% in the pediatric age group. Meningiomas in the posterior fossa in the pediatric period do not initially come to mind. In the case presented here, there was a cystic meningioma showing heterogenous contrast and obstructive hydrocephaly was observed associated with 4th ventricle pressure. the tumor was totally removed, then the ventriculo peritoneal shunt was applied.

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.

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.

[Surgical treatment of intracranial meningiomas in Nouakchott, Mauritania]

Meningiomas are frequently encountered tumours in neurosurgery. However, there is a paucity of data concerning their epidemiology, their clinical characteristics and their treatment compared to gliomas. This study aims to identify the epidemiological profile and to assess the quality of treatment of intracranial meningiomas (ICM) at the National Hospital Center in Nouakchott, Mauritania. We conducted a retrospective study of patients who had undergone surgery for the treatment of ICM between September 2013 and September 2016. Thirty-two patients had undergone surgery for the treatment of ICM (26.6%). The average age was 45.12 (± 13.8 years) among whom 75% were women. The average length of stay in hospital had been 13 days (± 7 days). The mean time between symptom onset and diagnosis had been 10 months (±5months). The mean size of ICM had been 5.07cm (±2.00cm) ranging from 2.5cm to 10.5cm. Complementary MRI had been performed in 46.8% of patients after brain CT scan. In our series, 38% of ICM had grown on brain convexity. The mean surgical time had been 23.91 days (±17days). The quality grade of surgical resection assigned according to Simpson score was Grade I (66%), Grade II (19%), Grade III (6%), Grade IV (9%). The histological grade assigned according to the 2007 WHO classification was Grade I (93%), Grade II-III (7%). The overall operative mortality was (n=3, 9.4%). The development of technical equipment in the department of neurosurgery, radiology and of equipment in anesthesia and intensive care will contribute to improve outcomes and to reduce mortality rates.

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.

Radiation Therapy for Residual or Recurrent Atypical Meningioma: The Effects of Modality, Timing, and Tumor Pathology on Long-Term Outcomes

BACKGROUND

Optimal use of stereotactic radiosurgery (SRS) vs external beam radiation therapy (EBRT) for treatment of residual/recurrent atypical meningioma is unclear.

OBJECTIVE

To analyze features associated with progression after radiation therapy.

METHODS

Fifty radiation-naive patients who received SRS or EBRT for residual and/or recurrent atypical meningioma were examined for predictors of progression using Cox regression and Kaplan-Meier analyses.

RESULTS

Thirty-two patients (64%) received adjuvant radiation after subtotal resection, 12 patients (24%) received salvage radiation after progression following subtotal resection, and 6 patients (12%) received salvage radiation after recurrence following gross total resection. Twenty-one patients (42%) received SRS (median 18 Gy), and 7 (33%) had tumor progression. Twenty-nine patients (58%) received EBRT (median 54 Gy), and 13 (45%) had tumor progression. Whereas tumor volume (P = .53), SRS vs EBRT (P = .45), and adjuvant vs salvage (P = .34) were not associated with progression after radiation therapy, spontaneous necrosis (hazard ratio [HR] = 82.3, P < .001), embolization necrosis (HR = 15.6, P = .03), and brain invasion (HR = 3.8, P = .008) predicted progression in univariate and multivariate analyses. Tumors treated with SRS/EBRT had 2- and 5-year actuarial locoregional control rates of 91%/88% and 71%/69%, respectively. Tumors with spontaneous necrosis, embolization necrosis, and no necrosis had 2- and 5-year locoregional control rates of 76%, 92%, and 100% and 36%, 73%, and 100%, respectively (P < .001).

CONCLUSION

This study suggests that necrosis may be a negative predictor of radiation response regardless of radiation timing or modality.

ABBREVIATIONS

AM, atypical meningiomaEBRT, external beam radiation therapyGTR, gross total resectionLC, locoregional controlOS, overall survivalPOE, preoperative embolizationRT, radiation therapySRS, stereotactic radiosurgerySTR, subtotal resection.

Clinicopathological and molecular characteristics of pediatric meningiomas

Molecular and clinical characteristics of pediatric meningiomas are poorly defined. Therefore, we analyzed clinical, morphological and molecular profiles of pediatric meningiomas. Forty pediatric meningiomas from January 2002 to June 2015 were studied. 1p36, 14q32 and 22q-deletion were assessed by fluorescent in situ hybridization and mutations of most relevant exons of AKT, SMO, KLF4, TRAF and pTERT using sequencing. Expression of GAB1, stathmin, progesterone receptor (PR), p53 along with MIB-1 LI was examined using immunohistochemistry. There were 36 sporadic and four NF2 associated meningiomas. Among sporadic meningiomas, the majority (72.2%) of cases harbored 22q-deletion. Difference in frequency of combined 1p/14q deletion in Grade-I versus Grade-II/III tumors was not significant (13.7% vs 28.5%, P = 0.57). PR immunoreactivity was seen in 65.5% of Grade-I and 14.2% of Grade-II/III tumors (P = 0.03). The majority (97.2%) of meningiomas were immunonegative for p53. Stathmin and GAB co-expression was observed in 58.3% of cases. Notably, AKT, SMO, KLF4, TRAF7 (exon 17) and pTERT mutations were seen in none of the cases analyzed. 1p/14q codeletion was frequent in skull base as compared to non-skull base meningiomas (23% vs 11.1%, P = 0.37). All NF2 meningiomas harbored 22q-deletion and showed GAB and stathmin co-expression while none showed 1p/14q loss. Pediatric meningiomas share certain phenotypic and cytogenetic characteristics with adult counterparts, but GAB and stathmin co-expression in the majority of cases and non-significant difference in frequency of 1p/14q co-deletion between low- and high-grade meningiomas indicate an inherently aggressive nature. Characteristic AKT/SMO, KLF4/TRAF7 and pTERT genetic alterations seen in adults are distinctly absent in pediatric meningiomas.

Intra-Arterial MR Perfusion Imaging of Meningiomas: Comparison to Digital Subtraction Angiography and Intravenous MR Perfusion Imaging

BACKGROUND AND PURPOSE

To evaluate the ability of IA MR perfusion to characterize meningioma blood supply.

METHODS

Studies were performed in a suite comprised of an x-ray angiography unit and 1.5T MR scanner that permitted intraprocedural patient movement between the imaging modalities. Patients underwent intra-arterial (IA) and intravenous (IV) T2* dynamic susceptibility MR perfusion immediately prior to meningioma embolization. Regional tumor arterial supply was characterized by digital subtraction angiography and classified as external carotid artery (ECA) dural, internal carotid artery (ICA) dural, or pial. MR perfusion data regions of interest (ROIs) were analyzed in regions with different vascular supply to extract peak height, full-width at half-maximum (FWHM), relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV), and mean transit time (MTT). Linear mixed modeling was used to identify perfusion curve parameter differences for each ROI for IA and IV MR imaging techniques. IA vs. IV perfusion parameters were also directly compared for each ROI using linear mixed modeling.

RESULTS

18 ROIs were analyzed in 12 patients. Arterial supply was identified as ECA dural (n = 11), ICA dural (n = 4), or pial (n = 3). FWHM, rCBV, and rCBF showed statistically significant differences between ROIs for IA MR perfusion. Peak Height and FWHM showed statistically significant differences between ROIs for IV MR perfusion. RCBV and MTT were significantly lower for IA perfusion in the Dural ECA compared to IV perfusion. Relative CBF in IA MR was found to be significantly higher in the Dural ICA region and MTT significantly lower compared to IV perfusion.

Use of Tranexamic Acid Is Associated with Reduced Blood Product Transfusion in Complex Skull Base Neurosurgical Procedures: A Retrospective Cohort Study

BACKGROUND

Compared with other procedures, complex skull base neurosurgery has the potential for increased intraoperative blood loss yet coagulation near eloquent cranial structures should be minimized. The safety and efficacy of the antifibrinolytic, tranexamic acid in elective neurosurgical procedures is not known. Our primary objective was to determine the relationship between the use of tranexamic acid and transfusion at our institution. Our secondary objective was to determine the incidence of adverse events associated with the use of tranexamic acid.

METHODS

In this retrospective cohort study, we included all patients who underwent complex skull base neurosurgical procedures at our institution between 2001 and 2013. Tranexamic acid was introduced during these procedures in 2006. Patient and surgical variables, transfusion data, and adverse events in the perioperative period were abstracted from the medical record. The rates of transfusion and adverse events were compared between patients who did and did not receive tranexamic acid. Multivariate regression was used to identify independent predictors of perioperative transfusion.

RESULTS

We compared 245 patients who received tranexamic acid with 274 patients who did not receive the drug during the study period. The 2 groups were similar, with the exception that patients who received tranexamic acid had larger tumors (mean, 3.5 vs 2.9 cm; P < 0.001) and longer procedures (mean, 7.2 vs 6.2 hours, P < 0.001). The rate of perioperative transfusion in patients who received tranexamic acid was lower (7% vs 13%, P = 0.04). After adjusting for preoperative hemoglobin, tumor diameter, and surgical procedure category, the use of tranexamic acid was independently predictive of perioperative transfusion (adjusted odds ratio, 0.32; 95% confidence interval, 0.15-0.65, P = 0.002). The rates of thromboembolic events and seizure were similar between the 2 groups.

CONCLUSIONS

Our results demonstrate that tranexamic acid use is associated with reduced transfusion rates in our study population, with no apparent increase in seizure or thrombotic complications. Our data support the need for further randomized clinical trials to evaluate the efficacy and safety of tranexamic acid on perioperative blood loss during complex skull base neurosurgery.

Relevance of Simpson grading system and recurrence-free survival after surgery for World Health Organization Grade I meningioma

OBJECTIVE The clinical significance of the Simpson system for grading the extent of meningioma resection and its role as a predictor of the recurrence of World Health Organization (WHO) Grade I meningiomas have been questioned in the past, echoing changes in meningioma surgery over the years. The authors reviewed their experience in resecting WHO Grade I meningiomas and assessed the association between extent of resection, as evaluated using the Simpson classification, and recurrence-free survival (RFS) of patients after meningioma surgery. METHODS Clinical and radiological information for patients with WHO Grade I meningiomas who had undergone resective surgery over the past 20 years was retrospectively reviewed. Simpson and Shinshu grading scales were used to evaluate the extent of resection. Statistical analysis was conducted using Kaplan-Meier curves and Cox proportional-hazards regression. RESULTS Four hundred fifty-eight patients were eligible for analysis. Overall tumor recurrence rates for Simpson resection Grades I, II, III, and IV were 5%, 22%, 31%, and 35%, respectively. After Cox regression analysis, Simpson Grade I (extensive resection) was revealed as a significant predictor of RFS (p = 0.003). Patients undergoing Simpson Grade I and II resections showed significant improvement in RFS compared with patients undergoing Grade III and IV resections (p = 0.005). Extent of resection had a significant effect on recurrence rates for both skull base (p = 0.047) and convexity (p = 0.012) meningiomas. Female sex and a Karnofsky Performance Scale score > 70 were also identified as independent predictors of RFS after resection of WHO Grade I meningioma. CONCLUSIONS In this patient cohort, a significant association was noted between extent of resection and rates of tumor recurrence. In the authors' experience the Simpson grading system maintains its relevance and prognostic value and can serve an important role for patient education. Even though complete tumor resection is the goal, surgery should be tailored to each patient according to the risks and surgical morbidity.

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.

Preoperative embolization of intracranial hemangiopericytomas: case series and introduction of the transtumoral embolization technique

Background and purpose

Hemangiopericytomas (HPCs) are rare dural-based neoplasms. Preoperative embolization of these notoriously hypervascular tumors can be challenging as they often receive their dominant blood supply from pial feeders arising from the internal carotid artery (ICA) or vertebrobasilar (VB) circulation. This study reviews our historical experience with HPC embolization and introduces the transtumoral technique for backfilling pial tumor vasculature by delivering Onyx-18 through diminutive external carotid artery (ECA) feeders.

Methods

A retrospective review of all preoperative HPC embolizations performed at Anonymous University #1 (September 2002–November 2014) and Anonymous University #2 (January 2014–November 2014) is presented.

Results

Fifteen patients with pathologically confirmed HPC underwent 17 embolizations. More extensive devascularization percentages were achieved for HPCs with primarily ECA blood supply (76.4±10.7%; n=6) than with HPCs supplied via the ICA/VB circulation (57.9±26.9%; n=8; p=0.046). There was a trend towards greater devascularization of ICA/VB-dominant HPCs embolized with Onyx (70.0±34.6%; n=4) versus polyvinyl alcohol particles (33.3±15.3%; n=3). The extent of angiographic devascularization negatively correlated with intraoperative blood loss (rho=−0.71; p=0.005). There were no embolization-related complications.

Conclusions

The extent of preoperative embolization of HPCs correlates with decreased intraoperative blood loss. However, HPCs with an ICA/VB-dominant blood supply remain challenging embolization targets, demonstrating reduced devascularization percentages compared with ECA-dominant counterparts. The authors favor the use of Onyx for ICA/VB-dominant HPCs, noting a trend towards an improved devascularization rate.

The role of preoperative embolization for intracranial meningiomas

Object

As endovascular techniques have become more advanced, preoperative embolization has become an increasingly used intervention in the management of meningiomas. To date, however, no consensus has been reached on the use of this technique. To clarify the role of preoperative embolization in the management of meningiomas, the authors conducted a systematic review of case reports, case series, and prospective studies to increase the current understanding of the management options for these common lesions and complications associated with preoperative embolization.

Methods

A PubMed search was performed to include all relevant studies in which the management of intracranial meningiomas with preoperative embolization was reported. Immediate complications of embolization were reported as major (sustained) or minor (transient) deficits, death, or no neurological deficits.

Results

A total of 36 studies comprising 459 patients were included in the review. Among patients receiving preoperative embolization for meningiomas, 4.6% (n = 21) sustained complications as a direct result of embolization. Of the 21 patients with embolization-induced complications, the incidence of major complications was 4.8% (n = 1) and the mortality rate was 9.5% (n = 2).

Conclusions

Preoperative embolization is associated with an added risk for morbidity and mortality. Preoperative embolization may be associated with significant complications, but careful selection of ideal cases for embolization may help reduce any added morbidity with this procedure. Although not analyzed in the authors' study, embolization may still reduce rates of surgical morbidity and mortality and therefore may still have a potential benefit for selected patients. Future prospective studies involving the use of preoperative embolization in certain cases of meningiomas may further elucidate its potential benefit and risks.

Management of pediatric intracranial meningiomas: an analysis of 31 cases and review of literature

OBJECTIVE

The purpose of this study is to understand the epidemiology, clinical features, behavior, and the prognostic factors that influence the outcome of intracranial meningiomas in children.

METHODS

Thirty-one patients with age less than 18 years who underwent surgery for intracranial meningiomas during the period of at 1988-2012 at Voluntary Health Services Hospital, Chennai, India were studied. These formed 3.7 % of the total 831 cases of intracranial meningiomas operated at the institute.

RESULTS

The study group included 22 (71 %) males and 9 (29 %) females. The mean age of presentation was 15 years, with the youngest being 9 months old. Two (6 %) had evidence of neurofibromatosis type 2 (NF2). The most common symptoms at presentation were seizures in 11 (35.5 %), weakness of limbs in 11 (35.5 %), and raised intracranial pressure in 10 (32 %). Convexity meningiomas were seen in 16 (51 %) and skull base in 15(49 %). Multiple meningiomas was seen in two (6 %) of the patients and intraventricular location was found in one patient (3 %). Two (6 %) had evidence of NF2. Gross total excision was achieved in 26 (83 %) and subtotal excision in 5 (17 %). WHO grade I was found in 20 (64 %) and higher grade was seen in 11 (36 %). The mean follow-up was 46.2 months. Recurrence was seen in 20 patients (64 %). In patients with higher grade or with recurrence resurgery and radiotherapy was given. Three (9 %) had multiple recurrences. On a mean follow-up of 46.2 months, 25 patients (81 %) were neurologically intact, 5 (16 %) were having moderated disability, and 1 (3 %) patient died.

CONCLUSIONS

Childhood meningiomas are uncommon lesions with a slight male predominance. They can have a varied clinical presentation. Higher grade is found more frequently compared with adults. Gross total resection is the goal and in higher grade meningiomas radiotherapy helps as a good adjuvant. Though the rate of recurrence is high, resurgery and radiotherapy gives a good outcome.

Preoperative onyx embolization of meningiomas fed by the ophthalmic artery: a case series

Embolization of head and neck hypervascular tumors is a well-established therapeutic technique. Preoperative embolization reduces intraoperative blood loss, shortens the length of surgery, and decreases surgical morbility and mortality. This study assesses the safety and efficacy of preoperative embolization of meningiomas fed by the OPH by using Onyx liquid embolic agent.

Embolization of Skull Base Meningiomas and Feeding Vessels Arising From the Internal Carotid Circulation

BACKGROUND:

Practice patterns regarding the preoperative embolization of skull base tumors vary widely among institutions and are driven by surgeon preference and concerns about safety.

OBJECTIVE:

We present a recent experience at our institution with a specific focus on procedural decision-making, embolization of vessels arising from the internal carotid circulation, and complication rates.

METHODS:

During a 7.5-year period, 262 meningiomas were referred for embolization. of which 119 (45%) originated from the skull base. Tumors were categorized by location, feeding artery origin, and arteries embolized. Complication rates were reviewed.

RESULTS:

Sixty-four of 119 patients with skull base tumors (54%) underwent embolization of at least 1 feeding artery. Feeding arteries arose from the external carotid artery (ECA) circulation in 26 (22%), the internal carotid artery (ICA) circulation in 30 (25%), a combination of ECA/ICA/Vert in 54 (45%), and had only pial supply in 10 (8%). In total, 15 of 85 (18%) ICA feeding vessels were embolized. This included 9 of 28 vessels from the meningohypopheseal trunk, 3 of 4 vessels from the anterior temporal artery, 1 of 35 vessels from the ophthalmic artery, 1 of 8 vessels directly from the ICA, and 1 of 5 vessels from the inferolateral trunk. Complete devascularization occurred in 6 of 64 patients; subtotal devascularization was seen in 58 of 64. The overall angiographic complication rate for all meningiomas embolized in the study period was 2.5% (5/199). None of the complications occurred in the skull base group.

CONCLUSION:

Preoperative embolization of skull base meningiomas and ICA feeding vessels can be done with low complication rates when intraprocedural decision-making favors complication avoidance over complete devascularization.

Meningiomas in children: A study of 18 cases

BACKGROUND

Intracranial meningiomas are rare tumors in children accounting for 0.4-4.6% of all primary brain tumors in the age group of 0-18 years.

OBJECTIVE

To retrospectively analyze the epidemiological profile, clinical features, radiological findings, type of excision, histopathological findings, and overall management profile of these patients.

MATERIALS AND METHODS

Eighteen consecutive cases of meningioma in patients under 18 years of age admitted and operated at our institute between the years 1974-2005 were included in this study.

RESULTS

The mean age of patient at presentation to our hospital was 12.81 years. The male to female ratio was 1.57:1. The median preoperative duration of symptoms was 1.2 years. An increased incidence was seen in patients with neurofibromatosis. Intraventricular and skull base locations were common. Total tumor excision was achieved in all cases.

CONCLUSION

A higher incidence of atypical and aggressive meningiomas is seen in children. Children with complete resection and a typical benign histology have a good prognosis.

The utility of onyx for preoperative embolization of cranial and spinal tumors

OBJECTIVE

To assess the utility, technical factors, and complications associated with the use of Onyx (Micro Therapeutics, Inc., Irvine, CA) for preoperative embolization of cranial and spinal tumors.

METHODS

We reviewed a prospectively accumulated database for patients in whom Onyx was used for preoperative embolization of cranial and spinal tumors over a 19-month period. The patients' demographic characteristics, tumor type and location, embolic agents used, arteries catheterized, and associated complications were assessed. Specific attention was focused on technical factors associated with the use of Onyx that differed from the use of other commonly used embolic materials.

RESULTS

Ten patients (four female and six male; age range, 11-60 yr) underwent preoperative embolization with Onyx before cranial or spinal tumor resection. Tumors included three juvenile nasal angiofibromas, two meningiomas, two hemangioblastomas, two metastases (renal cell and thyroid), and one giant cell tumor. Onyx embolization was performed in 43 vessels over 11 treatment sessions. There were no complications related to the embolization procedures. Deep penetration of the embolic agent into the tumor was documented through preoperative imaging or surgical pathological specimens.

CONCLUSION

Preoperative embolization of cranial and spinal tumors can be performed safely. Specific technical advantages of Onyx included deep penetration of lesions producing extensive tumor infarction, the ability to embolize extensive portions of the tumors through fewer arterial catheterizations, and the safety of catheter withdrawal despite often substantial reflux along the embolic catheter.

Pediatric intracranial meningiomas--do they differ from their counterparts in adults?

AIM

Meningiomas are very rare in children comprising only 0.44.1% of pediatric age tumors and only 1.5-1.8% of all intracranial neoplasms. We analyzed the clinical, pathological and management profile of these rare tumors and elucidated their differences from meningiomas in adults.

METHODS

From 1990 to 2005, 33 patients belonging to the pediatric age group with intracranial meningiomas were treated in NIMHANS.

RESULTS

There were 19 male and 14 female children. The duration of symptoms ranged from 1 to 60 months. The study had a mean follow-up of 23.4 months. The commonest presenting symptoms were headache (90.9%) and visual disturbances (51.5%). Three patients had associated neurofibromatosis. Calcification was noticed in 22% of the tumors. Intraventricular meningiomas were the commonest (24.2%). Gross total or near total resection was possible in 22 out of 33 patients. Nine patients had reversible postoperative motor deficits. Fibrous meningioma was the commonest histological subtype (24.2%). Five patients had atypical or anaplastic subtypes. Adjuvant radiotherapy was administered in 4 patients. Six patients had recurrences and underwent surgery. Ten patients required either staged procedures or multiple surgeries for the recurrence/residual tumors.

CONCLUSION

Pediatric meningiomas are rare tumors and differ from those in adults by their male predominance, atypical locations, higher rates of malignant subtypes, recurrence and association with neurofibromatosis. Surgical management is challenging because of atypical location.

Embolization in the External Carotid Artery

The technical skill set of peripheral interventional radiologists is well-suited to the performance of most transcatheter embolization procedures in the external carotid artery (ECA). These procedures center in large part on hypervascular tumors, epistaxis, and trauma. ECA embolization in the trauma patient is well-defined, albeit in small patient series. The transcatheter treatment of epistaxis is still mostly reserved for cases that are intractable to conservative therapy. Preoperative embolotherapy for vascular tumors remains popular, although it is somewhat controversial in terms of its risk-benefit ratio. The purpose of this review is to highlight pertinent anatomy, selected technical procedural aspects, and the available literature to better characterize the role of ECA embolization in the hands of the practicing peripheral interventionist.

Low Morbidity Associated With the Use of Nbca Liquid Adhesive for Preoperative Transarterial Embolization of Central Nervous System Tumors

OBJECTIVE

To determine the safety and efficacy of preoperative embolization of central nervous system (CNS) tumors with n-butyl cyanoacrylate (NBCA) liquid adhesive.

METHODS

Over a 6-yr period, 35 consecutive patients (12 women, 23 men; mean age, 42 yr; range, 6 mo to 75 yr) with a CNS tumor underwent preoperative embolization with NBCA. Tumor type, location, endovascular and surgical treatment, percent of tumor embolization, estimated blood loss, and neurological deficits related to embolization were evaluated retrospectively.

RESULTS

One hundred feeding arteries were embolized (mean, 3 vessels/patient). In only one case (3%) a normal artery was inadvertently occluded by the embolization. During follow-up the resulting neurological deficit resolved completely. There were no neurological deficits or inadvertent embolization events in the remaining 34 cases. The mean percent of tumor embolized was 68%, but did not significantly correlate with operative blood loss (Pearson's correlation coefficient, r = 0.049).

CONCLUSION

In experienced hands, CNS tumors can be embolized with NBCA liquid adhesive with a high degree of safety and efficacy. We believe that adroit embolization technique with NBCA and other embolisates should be part of the contemporary neuroendovascular armamentarium.

Volumetric thermal devascularization of large meningiomas

Object. Controlling hemorrhage is crucial in the safe and efficient removal of large meningiomas. Intravascular embolization is not always a satisfactory means of accomplishing this goal because of the procedure's hemostatic effect and risk of complications. The authors in this study used a volumetric thermal ablation technique incorporating radiofrequency energy, image guidance, and local temperature control to devascularize tumor tissue.

Methods. Five patients with large meningiomas were treated. The target and orientation of the radiofrequency thermal ablation (RFTA) were simulated preoperatively to maximize devascularization of the lesion without thermal injury to adjacent critical structures. Image fusion, three-dimensional reconstruction, and image-guided methods provided for optimized trajectories and targets for insertion of the RFTA needle. During ablation, local temperatures of the tissue being cauterized were monitored continuously to limit the ablated lesion to within the target volume.

The effects of devascularization and the softening of the tumor parenchyma facilitated lesion removal. The intracranial ablated meningioma changed into necrotic tissue and shrank within a few months. Histopathological examination of the ablated lesion revealed sharply demarcated coagulation necrosis.

Conclusions. Volumetric thermal devascularization can be applied safely in the treatment of large meningiomas to facilitate surgical manipulation of the lesion as well as to reduce its size palliatively. The procedure's usefulness should be studied further in a larger number of cases with different tumor characteristics.

Clinicopathologic assessment and grading of embolized meningiomas: a correlative study of 64 patients

BACKGROUND

Preoperative embolization of meningiomas is commonly performed to minimize intraoperative bleeding, thereby facilitating surgery and reducing the necessity for transfusion. However, the resulting necrosis and compensatory proliferation reportedly have hampered subsequent histologic grading.

METHODS

The clinicopathologic features of 64 meningiomas embolized between 1989 and 1997 were assessed. Tumors were graded according to recently published criteria.

RESULTS

A good embolization result (> 75% reduction in angiographic blush) was achieved in 52%. Histologically, embolized meningiomas showed higher frequencies of necrosis (89%), nuclear atypia (72%), macronucleoli (58%), sheeting (31%), high mitotic index (30%), and brain invasion (14%) when compared with nonembolized counterparts. Median mitotic and MIB-1 indices were slightly elevated (1.5 of 10 high-power fields and 1.6%, respectively). A significant degree of necrosis (> 10%) was found in 43% and was only roughly correlated with extent of angiographic blush reduction or embolization particle size. Histologic grade was benign in 57.8%, atypical in 40.6%, and anaplastic in 1.6%. At last follow-up, there were 13 recurrences, 11 in the atypical/anaplastic (41%) versus 2 in the benign (5%) subsets (P = 0.001).

CONCLUSIONS

The authors conclude that 1) their grading scheme accurately stratifies embolized meningiomas, 2) extent of necrosis is difficult to predict using standard clinical parameters, and 3) their high incidence of atypical meningioma more likely reflects patient selection biases rather than artifacts induced by the embolization procedure.

Meningiomas of the orbit: contemporary considerations

Meningiomas are the most frequently occurring benign intracranial neoplasms. Compared with other intracranial neoplasms they grow slowly, and they are potentially amenable to a complete surgical cure. They cause neurological compromise by direct compression of adjacent neural structures. Orbital meningiomas are interesting because of their location. They can compress the optic nerve, the intraorbital contents, the contents of the superior orbital fissure, the cavernous sinus, and frontal and temporal lobes. Because of its proximity to eloquent neurological structures, this lesion often poses a formidable operative challenge. Recent advances in techniques such as preoperative embolization and new modifications to surgical approaches allow surgeons to achieve their surgery-related goals and ultimately optimum patient outcome. Preoperative embolization may be effective in reducing intraoperative blood loss and in improving intraoperative visualization of the tumor by reducing the amount of blood obscuring the field and allowing unhurried microdissection. Advances in surgical techniques allow the surgeon to gain unfettered exposure of the tumor while minimizing the manipulation of neural structures. Recent advances in technology—namely, frameless computer-assisted image guidance—assist the surgeon in the safe resection of these tumors. Image guidance is particularly useful when resecting the osseous portion of the tumor because the tissue does not shift with respect to the calibration frame. The authors discuss their experience and review the contemporary literature concerning meningiomas of the orbit and the care of patients harboring such lesions.

Preoperative tumor embolization

We performed an embolization of tumors which we considered to need preoperative embolization, such as deep-seated tumors, or hypervascular tumors. We experienced 12 such cases in the two-year period from September 1996. Eight cases were meningiomas, one case was a hemangiopericytoma, one case was an angiofibroma and two cases were glomus tumors. As embolic material, we usually use estrogen-alcohol and polyvinyl acetate which soften the tumor. When a provacative test is either impossible or positive, the distal induction of a microcatheter is impossible or a dangerous anastomosis is present, we select polyvinyl alchol particles (120 approximately 250mum) and liquid coils. We performed an embolization of a very hypervascular tumor, juvenile angiofibroma, by a direct tumor puncture, using a mixure of N-butylcyanoacrylate, lipiodol and tantalum powder. Angiography in all cases showed a reduction of the tumor stain. The embolic method should be selected based on a combination of such factors as the purpose of embolization, the identification of the feeding artery and the histological findings.