Ultrastructural study of the microvasculature in the cerebral bed adjacent to arteriovenous malformation nidus: A proof against endovascular embolization

Background: The pathology of cerebral arteriovenous malformations (AVMs) is still a matter of considerable debate. Endovascular embolization as a treatment modality for AVMs is not yet well established. Methods: The study was conducted on seven AVM cases that had been operated upon without preoperative endovascular embolization, three cases that had preoperative endovascular embolization, and two controls. All were examined using transmission electron microscopy. Results: The capillaries of the preoperatively embolized cases showed changes at the level of their lining endothelium and surrounding extracellular matrix. Conclusion: Preoperative endovascular embolization is proven to be harmful to the parenchymal capillaries in the bed of resected AVMs.