Arteriovenous Malformations (AVMs)
AVMs can form anywhere in the brain or spinal cord; wherever arteries and veins exist.
AVMs compromise oxygen delivery to the brain or spinal cord by altering normal patterns of blood flow.
Pial and Dural AVM of the brain
Pial AVMs are the most common and are congenital (you are born with it). Usually no symptoms present until adulthood.
Dural AVMs are uncommon and thought to be caused by trauma, surgery, thrombosis of an adjacent venous sinus, or veno-occlusive disease.
The vessels of an AVM are abnormal and may leak or rupture (hemorrhage). The symptoms associated with rupture are severe headache which is abrupt in onset, nausea, vomiting, and loss of consciousness. Seizures may occur with or without rupture of the AVM.
Most AVM’s are detected only after they have ruptured. Diagnostic studies performed for detection are MRI of the Brain and Cerebral Angiography (a procedure in which a contrast dye is injected through a catheter inserted in the femoral artery in the thigh).
The primary goal of AVM treatment is to avoid hemorrhage. Treatment options include one of the following: surgical removal, gamma knife or stereotactic radiosurgery, or endovascular embolization. The best treatment option for you will be discussed with you by the surgeon at the time of your evaluation.
Arteriovenous Malformations of the Spinal Cord and its Coverings
Spinal cord AVMs and spinal dural AVMs (AVMs of the spinal cord's covering or dura) are abnormal connections between the arteries and veins that occur within the spinal cord or its coverings. These malformations lack the normal blood vessels or capillaries which lay between the arteries and veins and which serve to slow the blood flow allowing it to perform its normal functions. The resulting increase in blood flow through the AVM can cause an increase in the pressure within the veins and a decreased ability to clear blood from other vessels, diminishing blood flow to adjacent areas of the brain.This slowing of blood flow in other areas of the brain and the increased pressure within the veins draining the AVM can either cause a loss of function in the spinal cord or hemorrhage.
Spinal cord AVMs may present with abrupt pain, or progressive loss of strength, sensation, body control, and bowel, bladder, and sexual function. These malformations can often be seen on high quality, high resolution contrast enhanced MRI of the spine, but usually require spinal angiography to confirm the diagnosis. They usually can be treated by embolization, however, some are best treated by open neurosurgical procedures using the microscope. In some patients, the risk of damage to neurologic function is greater than the potential benefit from complete treatment; these patients may be partially treated, or followed. Judgment and experience are crucial to appropriate treatment, since these are rare lesions in very sensitive areas of the nervous system.