Clinicopathological Investigation of AVMs Embolized with HEMA-MMA. A New Non-Adhesive Liquid Material

We have recently developed a non-adhesive liquid embolic agent, hydroxyethylmethacrylate methylmethacrylate copolymer (HEMA-MMA), and used it for arteriovenous malformations (AVMs) in the central nervous system. To evaluate the toxicity and usefulness of this agent, we made a clinicopathological study of AVMs that were embolized with it and then excised surgically. This study includes ten cases: nine with pial AVM and one with scalp AVM. In a pathological study, special attention was paid to vascular and perivascular inflammation, angionecrosis, recanalization of the embolized vessels, and foreign body reactions. Inflammation was absent or very mild regardless of the interval between embolization and excision. There was no angionecrosis. Recanalization could be expected to occur in the partially occluded vessel. Foreign body reactions such as infiltration of monocytes or giant cells, and proliferation of fibroblasts or capillaries were also not seen in any case. It was concluded that HEMA-MMA is an excellent embolic material that is easy to handle, less vasotoxic than other agents, and highly his-tocompatible.