This procedure is done to eliminate or greatly reduce the pain caused by a blood vessel (usually an artery) pressing on the trigeminal nerve in the face. A small opening is made in the skull, and the surgeon negotiates around the dura (protective covering of the brain) and the cerebellum to find the problem artery. He then pushes the artery away from the nerve, relieving pressure and pain, and inserts a sterile pad to protect the nerve from further contact with the vessel.