A craniotomy is the surgical removal of part of the bone from the skull to expose the brain. Specialized tools are used to remove the section of bone called the bone flap. The bone flap is temporarily removed, then replaced after the brain surgery has been done.
Some craniotomy procedures may use the guidance of computers and imaging (magnetic resonance imaging [MRI] or computerized tomography [CT] scans) to reach the precise location within the brain that is to be treated. This technique requires the use of a frame placed onto the skull or a frameless system using superficially placed markers or landmarks on the scalp. When either of these imaging procedures is used along with the craniotomy procedure, it is called stereotactic craniotomy.
Scans made of the brain, in conjunction with these computers and localizing frames, provide a three-dimensional image, for example, of a tumor within the brain. It is useful in making the distinction between tumor tissue and healthy tissue and reaching the precise location of the abnormal tissue.
Burr holes are small holes that a neurosurgeon makes in the skull. Burr holes are used to help relieve pressure on the brain when fluid, such as blood, builds up and starts to compress brain tissue.
A layer of thin tissues called meninges surround and help protect the brain. These meninges contain blood vessels that carry blood to and from the brain. The dura is the outermost of these meninges.
A head injury can cause one or more of these blood vessels to tear and bleed. A sudden tear might cause blood to build up very suddenly. With a small tear, the blood might build up more slowly. Blood might start to build up just below the dura mater. This causes something called a subdural hematoma. Tears in different blood vessels may cause blood to build up just above the dura layer, causing an epidural hematoma. A hematoma is when blood collects in an area and causes swelling.
This buildup of blood is dangerous. As the blood builds, it pushes up against the skull and has nowhere to go. If the blood starts to compress the brain, it can lead to symptoms or even death if not treated.