Preoperative embolization of intracranial meningiomas: our experience

Introduction. Meningiomas are extra-axial tumors,generally benign, originated by arachnoid cell degene-ration. They are more common in adults (40-60 years)and females. In 1973, Manelfe et al. first described preo-perative embolization of some meningiomas histotypes.Since then, the technique has remarkably improved, byusing micro-catheters and with the development ofmaterials used to perform the procedure, along withthe growing experience of neurosurgeons and neuro-radiologists. Several authors have shown that the pro-cedure reduces intraoperative bleeding. However, preo-perative embolization is still a matter of debate.Object. The objective of this study was to determinatethe benefits of preoperative embolization usingpolyvinyl alcohol (PVA) in selected patients, highlightingclinical indications to safely perform the technique.Materials and Methods. In the last 12 years, 50 patien-ts (13 males and 37 females, mean age 60.5) with adiagnosis of meningioma, underwent Digital Subtrac-tion Angiography (DSA) to assess the arterial supply ofthe tumor. 45 patients underwent endovascular preo-perative embolization of the tumor blush and 34 wereoperated on.Patients were divided into three groups: Group 1 (n =19), with preoperative embolization performed at least7 days before surgical operation, Group 2 (n = 15), withpreoperative embolization performed less than 7 daysbefore surgical operation, and Control Group (n = 16),surgically treated without previous embolization.Two criteria were chosen to perform endovascular tre-atment: a minimum tumor size of 4 cm and a tumorblood supply provided by external carotid artery (ECA)for at least 50%.Polyvinyl alcohol sponge particles (PVA) were used in32 embolized patients, Trysacril gelatin microspheres(Embospheres) were used only in 2 pts.Outcomes were evaluated taking into considerationsurgical operating time and blood transfusion during the operation. A statistical evaluation was performedcomparing these parameters between embolized pa-tients and a control group formed by patients surgicallytreated without previous embolization.Results and Conclusions. A statistically significant dif-ference was shown between Group 1 and 2, taking intoconsideration both variables: surgical time and blood-transfused volume were lower in Group 1. Similarly,blood-transfused volume was significantly less in Group1, compared to Control Group.On the contrary, despite a gap of nearly 30 minutesbetween the surgical mean time of Group 1 and ControlGroup, there was no statistically significant differencebetween the two groups, regarding this variable. Nopatients presented complications after angiography.In addition, having analyzed the hystopathological re-ports of those patients who underwent embolization(Group 1 and 2), we evaluated the status of tumornecrosis after the surgical removal. Interestingly, ne-crosis was found in 15/19 patients in Group 1. Amongthem, the areas of necrosis were described as massivein 5 cases, less massive in 7 cases, modest in 3 cases.Moreover, in 10 out of 19 patients of this Group, macro-scopical areas of necrosis were observed at surgery andthese patients had a significant benefit from operation.Among those patients who underwent surgery less than7 days after the embolization (Group 2), the areas ofmodest necrosis were reported in 4 out of 16 patients.In conclusion, pre-operative embolization with PVA inpatients with ≥ 4 cm intracranial meningiomas fed byECA branches for > 50% is a safe and effective procedu-re which reduces blood transfused volume during sur-gical operation.However, patients should undergo surgery at least 7days after embolization (areas of more necrosis), be-cause a shorter interval time has been correlated with alonger surgical time and a higher transfused bloodvolume.