How are you? Craniotomy is indicated for brain tumors, infections, abscesses, cerebral edema and bleeding within the skull. Like any operation, there are possible effects and complications of the surgery such as allergic reaction to the anesthetic, injury from the head pin fixing device, injury to facial muscle and sinuses, infection of the bone flap, seizures, bleeding, brain damage, brain swelling and even stroke. Prior to any operation, these are discussed by your surgeon and anesthesiologist. Take care and regards.