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Introduction
Procedure
Risks
Alternative Treatments
The brain is made up of tissue that is arranged in folds. Based on these folds, as well as functional and structural anatomy, four lobes have been designated, which are the frontal, parietal, occipital, and temporal lobes.
Various major functions are associated with the brain, including movement (motor), sensation (sensory), speech, and reading comprehension, as indicated in the figure below. When performing surgery on the brain, it is imperative that these areas do not become damaged in order to avoid significant deficits with these functions.
Craniotomy refers to any operation that requires the opening of the skull. A craniotomy may be done for a variety of reasons such as brain tumors, aneurysms, arteriovenous malformations, cavernous malformations, arachnoid cysts, traumatic brain injury, and many others.
The location, size, and shape of the craniotomy depends on the ares of the brain that needs to be accessed in order to perform the surgery. For classification purposes, a craniotomy is named roughly after the portion of the brain that it involves. For example, a craniotomy over the frontal lobe is called a frontal craniotomy, whereas one over the temporal lobe is called a temporal craniotomy. A craniotomy may also involve two or more adjacent lobes in which case the name of the craniotomy is made up of a hybrid of the involved lobes, such as frontotemporal craniotomy (involving the frontal and temporal lobes), temporoparietal craniotomy (involving the temporal and parietal lobes), or temporoparietooccipital craniotomy (involving the temporal, parietal, and occipital lobes). Certain types of craniotomy are better known for the region of the skull that they encompass (rather than the underlying brain), such as the pterional craniotomy that is centered around the pterion region of the skull (see below).
Once the skull has been opened, the brain's protective covering (called the dura mater) will be encountered, which needs to be opened in order to reach the brain tissue itself. At this point, further dissection may need to be done to reach the problematic area.
After induction of general anesthesia, an incision (1 in figure below) is planned over the region that requires the operation. In the figure below, a pterional craniotomy is planned, indicating that the opening in the skull will be in the pterion region of the skull (2 in figure below).
The skin and underlying muscle and other tissues are dissected off of the bone and reflected away, after which a drill is used to cut the skull and remove it.
At this point cut edge of the bone (1 in figure below) and the dura mater (2 in figure below) can be seen. An opening in the dura mater is planned (3 in figure below) and the dura mater is opened in order to gain access to the brain underneath.
After the dura mater has been opened, various structures may need to dissected and moved out of the way with retractors (1 in figure below), such as the brain (2 in figure below), blood vessels (3 in figure below), or nerves (4 in figure below).
After the dissection has been done and the problem has been fixed, the retractors are removed, and the dura mater is closed with sutures, after which the removed portion of the skull is replaced and fastened in placed using small metal (titanium) plates and screws (1 in figure below).
The incision is then closed prior to the termination of the operation.
Due to advances in medicine and technology, surgical procedures are generally considered to be safe, and a great majority of patients who undergo surgery will not experience any complications. However, there are certain risks involved in any procedure which are important to be aware of in order to make an informed treatment decision.
Risks Specific to this Procedure: The risks associated with this surgery include, but are not limited to, damage to brain leading to increased neurologic problems, impaired memory and/or cognition, weakness or paralysis, numbness, seizures, loss of speech, coma, and need for further surgery or treatment.
Infection: Invasion of tissue by bacteria or other germs occurs to some degree whenever a cut, incision or puncture is made. In most instances, through the natural defense mechanisms of the body, healing of the affected area occurs without difficulty. In some instances antibiotic medicines are prescribed and at times additional surgical measures may be necessary to combat infection.
Hemorrhage: The cutting of blood vessels causes bleeding and this occurs in every surgical incision. This bleeding is usually controlled without difficulty. At times, blood transfusions are required to replace blood loss. If blood transfusions are given, there are additional risks of liver inflammation, hepatitis, and the possibility of receiving Acquired Immune Deficiency Syndrome (AIDS). There is no absolutely reliable way to predict these unwanted reactions, some of which may be quite serious and even lead to death.
Drug Reactions: Unexpected allergies, lack of proper response to medications or illness caused by the prescribed drugs are possibilities. It is important for you to inform your physician and your anesthesiologist or certified registered nurse anesthetist of any problem you or your family have had with reactions to drugs and which medications you have taken in the past six months, including over-the-counter drugs, especially aspirin.
Anesthesia Reactions: There may be unusual or unexpected responses to the gases, drugs or methods used to anesthetize you which can lead to difficulties with lung, heart or nerve function. Eating or drinking before anesthesia increases the risks of vomiting which may cause significant complications. Inform your anesthesiologist or certified registered nurse anesthetist of problems you and your family have had with anesthesia.
Blood Vessel Inflammation and Clotting: It is impossible to predict the occurrence of blood vessel inflammation and clotting problems. If blood clots form, they can move from where they formed to other areas of the body and cause injury.
Injury to Other Organs: Because of the closeness of other organs to the area being operated on, there may be injury to other organs. The stress of surgery or the procedure may also harm other organ systems of the body.
The alternative management modalities for this procedure depend on the reason for which the craniotomy is being performed and vary from one problem to another. If the decision is made to not have this procedure, there may be associated risks which need to be discussed with a physician.
