A craniotomy is the surgical removal of part of the bone from the skull to expose the brain to access nerves and arteries within the skull, as well as any intracranial abnormality such as a tumor, aneurysm or hematoma. The opening required will vary in size, shape and location, depending on the treatment needed.
Some craniotomy procedures may utilize 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 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.
Other uses include stereotactic biopsy of the brain (a needle is guided into an abnormal area so that a piece of tissue may be removed for examination under a microscope), stereotactic aspiration (removal of fluid from abscesses, hematomas, or cysts), and stereotactic radiosurgery (such as gamma knife radiosurgery).
An endoscopic craniotomy is another type of craniotomy that involves the insertion of a lighted scope with a camera into the brain through a small incision in the skull.