Patient’s head will be held in place by a device to be removed at the end of the procedure. The skin and muscles are pulled up and clipped to control bleeding while providing access to the brain. Small burr holes are then made in the skull with a medical drill. The cut bone flap is lifted and removed to expose the thick outer protective covering of the brain called the dura.   Once the dura is opened to expose the brain, excess fluid will be allowed to flow out of the brain, if need be. Microsurgical instruments, such as magnification glasses or an operating microscope, may be used by the surgeon to enable a better view of the brain structures.