Surgery that is performed on the skull is usually referred to as craniotomy.

Surgery that is performed on the skull is usually referred to as craniotomy. This surgery involves temporarily opening the skull to allow for operation on or around the brain. 

This surgery is performed for several reasons, but the main reasons cranial surgery is done include:
 

• Tumors: Brain tumors include benign and more aggressive tumors, both of which often need surgical treatment or biopsy for diagnosis. Surgery for brain tumors ranges from minimally invasive biopsies or nearly non-invasive radiosurgery to more aggressive surgical approaches. Some tumors require more than one modality for diagnosis and treatment.

• Aneurysms: An aneurysm is an abnormal widening or ballooning of a portion of an artery due to weakness in the wall of the blood vessel. It is not clear exactly what causes aneurysms. Some aneurysms are present at birth, while defects in some of the parts of the artery wall may be responsible as well. Symptoms depend on the location of an aneurysm. If an aneurysm occurs near the body's surface, pain and swelling with a throbbing mass often are seen. Aneurysms within the body or brain often cause no symptoms. If an aneurysm ruptures, pain, low blood pressure, a rapid heart rate, and light-headedness may occur. 

• Head Injury: Trauma can vary from a mild bump on the head to a severe injury from motor vehicle accidents or falls. Surgery is not always needed for head injuries. Severe head injuries that result in blood clots in or on the brain will often require surgery. 

• Infection: Various types of brain infections develop many different symptoms which can depend on the age of the person, the type of bacteria, the type of infection, and the acuteness of the disease.