An arteriovenous malformation, or AVM, is a knot of abnormal arteries and veins. They have a high tendency to bleed, most often in young and middle-aged adults. AVMs can form in any part of the body, but they are especially of high concern when they form in the brain because of the risks of bleeding in this area. The size and location of AVMs vary in the brain. AVMs affect less than one percent of the population.
The type of treatment is based upon the size and location of the AVM. Treatment options include embolization, radiation therapy, and surgical removal. The advantage of surgical treatment is that a cure is immediate if all the AVM is removed. Some disadvantages include risk of bleeding, damage to nearby brain tissue, and stroke. Some AVMs in the brain are best treated by a craniotomy.
A craniotomy is a surgical procedure that involves removal of a portion of the skull to access the brain. This surgery is performed by a neurosurgeon while the patient is under anesthesia. A craniotomy can be performed on any part of the skull depending on the location of the brain that needs to be accessed. The portion of the skull that is cut out is called a bone flap.