Craniotomy with Dural Opening

A craniotomy opens the skull to reach the brain: burr holes are drilled, a bone flap is cut between them and lifted, and the flap is usually put back at the end. This page follows the craniotomy through its most delicate step, opening the dura mater, the tough outer covering of the brain that lies just under the bone. Once the dura is open, the brain itself is exposed, and everything the scrub person passes from then on (brain spoons, cottonoids, bipolar forceps) is about protecting the brain from pressure, drying and injury. Opening the dura is done in a set order. Bleeding on the dura is controlled first, and the dura is often tacked up to the bone so blood cannot collect above it after surgery. The dura is lifted with a hook or a traction stitch, nicked with a small blade and opened with scissors, while cottonoid patties are slid underneath to shield the brain. The edges are held back with traction sutures. At the end, the dura is closed watertight; if it will not close, a graft of the patient's own fascia or periosteum, or a collagen dural substitute, is sewn in. A dural sealant may be added over the suture line to keep spinal fluid from leaking. Craniotomy is done for tumors, aneurysms and arteriovenous malformations, blood clots after injury (epidural and subdural hematomas), and leaks of spinal fluid through a dura torn in a skull fracture. The dura is sometimes left open, for example under simple burr holes or after some posterior fossa operations. Risks include wound infection, meningitis, bleeding above or below the dura or into the brain, and nerve damage from the condition being treated or from the surgery itself.