Controversies in the role of preoperative embolization in meningioma management

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.

The safety and efficacy of preoperative embolization of meningioma with N-butyl cyanoacrylate

OBJECTIVE

Preoperative embolization of meningioma is commonly performed; however, there is no consensus on the best embolic material to reduce intraoperative blood loss and surgery time.

METHOD

We retrospectively assessed the safety and efficacy of 56 cases of preoperative embolization of the middle meningeal artery with N-butyl cyanoacrylate (NBCA) in 105 cases of surgery for meningioma. We also defined a blood loss to tumor volume ratio to compensate for bias caused by tumor volume, and analyzed limited cases (the embolized group n = 52, the non-embolized group n = 21) of the convexity, the parasagittal region, the falx, and the sphenoidal ridge.

RESULT

The blood loss to tumor volume ratio was significantly less in the embolized group (p < 0.007). Preoperative embolization could be useful for cases with the external carotid artery as the dominant feeder vessel (p < 0.02); however, the efficacy decreased for cases with an internal carotid artery feeder. Transient complications occurred in four cases (hemiparesis secondary to edema: two cases; intratumoral bleeding: one case; trigeminal nerve disorder: one case). The cases that showed a postoperative increase in edema or intratumoral bleeding were large tumors with the early filling of veins. For such cases, surgeons should pay close attention to slow injection speed and higher NBCA viscosity, not to cause the occlusion of draining vessels.

CONCLUSION

Tumor embolization with NBCA can be safely performed, and the procedure significantly reduces intraoperative blood loss.

Anterior and Posterior Ethmoidal Artery Ligation in Anterior Skull Base Meningiomas: A Review on Microsurgical Approaches

OBJECTIVE

Anterior skull base neoplastic and vascular lesions can receive significant blood supply from the anterior and posterior ethmoidal artery. Although useful in preoperative embolization of middle meningeal artery branches, endovascular techniques for the occlusion of anterior ethmoidal artery expose the parent vessel, the ophthalmic artery, to possible embolic complications, which can cause loss of vision. When dealing with anterior fossa giant meningiomas, moreover, it is not always possible to gain direct intracranial access to anterior ethmoidal arteries because of dimensions and invasiveness of these neoplasms. The aim of this review is to illustrate the anterior and posterior ethmoidal artery anatomy and the microsurgical approaches for extracranial ligation.

METHODS

We performed a literature review of the relevant microsurgical anatomy of these arteries; particular attention is given to anterior cranial fossa and medial orbital wall anatomy.

RESULTS

Our research found two surgical sites of arterial occlusion that can be best exposed with five microsurgical approaches.

CONCLUSIONS

A combination of different surgical and endovascular techniques before resection of hypervascular giant olfactory groove and planum sphenoidale meningiomas should always be considered. Microsurgical extracranial ligation of anterior and sometimes posterior ethmoidal arteries provides a safe and feasible option to limit blood loss during anterior skull base surgery.

Evaluation of Selective Arterial Embolization Effect by Chitosan Micro-Hydrogels in Hindlimb Sarcoma Rodent Models Using Various Imaging Modalities

PURPOSE

Embolization is mainly used to reduce the size of locally advanced tumors. In this study, selective arterial catheterization with chitosan micro-hydrogels (CMH) into the femoral artery was performed and the therapeutic effect was validated using different imaging methods.

METHODS

Male SD rats (n = 18, 6 weeks old) were randomly assigned into three groups: Group 1 as control, Group 2 without any ligation of distal femoral artery, and Group 3 with temporary ligation of the distal femoral artery. RR1022 sarcoma cell lines were inoculated into thigh muscle. After 1 week, CMH was injected into the proximal femoral artery. Different imaging modalities were performed during a 3-week follow-up.

RESULTS

The tumor size was significantly (P < 0.001) decreased in both Group 2 and Group 3 (P < 0.001) after selective arterial embolization therapy. (18)F-FDG-PET/CT revealed decreased intensity of (18)F-FDG uptake in tumors. The accumulation status of (125)I-CMH near the tumor was verified by gamma camera.

CONCLUSIONS

Appropriate selective arterial embolization therapy with CMH was.

Imaging of brain tumors

Neuroimaging plays a crucial role in diagnosis of brain tumors and in the decision-making process for therapy. Functional imaging techniques can reflect cellular density (diffusion imaging), capillary density (perfusion techniques), and tissue biochemistry (magnetic resonance [MR] spectroscopy). In addition, cortical activation imaging (functional MR imaging) can identify various loci of eloquent cerebral cortical function. Combining these new tools can increase diagnostic specificity and confidence. Familiarity with conventional and advanced imaging findings facilitates accurate diagnosis, differentiation from other processes, and optimal patient treatment. This article is a practical synopsis of pathologic, clinical, and imaging spectra of most common brain tumors.