What is normal perfusion pressure breach? Let’s say that a giant hemangioma is like a large reservoir that holds the water of many rivers. If the reservoir is suddenly eliminated, the water upstream will have nowhere to go. By the same token, if a giant hemangioma is suddenly removed, the blood that used to supply the giant hemangioma will wash out the brain and cause a brain hemorrhage. Normal perfusion pressure breakthrough syndrome: It refers to the long-term blood theft of malformed vessels, the adjacent small arteries are in a state of continuous expansion, the cerebral vessels lose their self-regulating ability, and once the arteriovenous malformation is removed, the cerebral vascular perfusion pressure rises, the cerebral arteries cannot contract reactively, and the brain is overperfused, resulting in diffuse cerebral edema and small artery rupture hemorrhage, etc. Normal perfusion pressure breakthrough (NBBP) Spetzler first proposed this theory in 1977, suggesting that after resection or embolization of giant cerebral AVM, blood is reintroduced to normal brain tissue around the lesion to restore its perfusion pressure to normal, and due to the long-term low perfusion pressure of small vessels in the brain tissue around the lesion and loss of autoregulation, these small vessels cannot contract to adapt to the rapid increase in perfusion pressure and As a result, the capillary bed of the brain tissue around the lesion cannot be protected, resulting in the rupture of the capillary bed, which is the main reason for the occurrence of edema and hemorrhage in the brain tissue around the lesion.