The skull base is the bottom portion of the skull. This area is extremely delicate because every nerve that connects the brain with the rest of the body must move through this area. In addition, this is where the large blood vessels that supply oxygen to the brain exist. The most common form of abnormality that would require surgery in this area is a tumor, often benign. This is also a common location for an abnormality of a blood vessel or aneurysm.
Skull base neurosurgery is usually performed by removing the bone at the base of the skull to expose the tumor or aneurysm with minimal manipulation to the brain. Otolaryngologists (physicians who treat the ear, nose and throat) and neurosurgeons at the The George Washington University Hospital can also join forces in certain cases to remove tumors endoscopically through the patient's nose, a natural opening, thus avoiding the facial or skull incisions associated with major surgery.
Doctors are unsure of what specifically causes skull-based tumors. In rare cases, they have been linked to radiation exposure and also genetics. The cause of aneurysms at the base of the skull also is largely unknown; however, a small percentage is genetically transmitted. Cigarette smoking and high blood pressure can cause aneurysms to grow and bleed.
Skull-based tumors usually do not show symptoms until they grow to a size where they exert pressure on the nerves and brain. These tumors can cause a variety of neurological symptoms such as headaches, vomiting, drowsiness, first-time seizures, double vision, facial pain or twitching, hearing loss, loss of balance or dizziness, hoarseness, speech difficulties, change in personality and tongue weakness. Aneurysms usually do not cause symptoms until they bleed. Tumors and aneurysms can be detected through tests such as MRI, CT, MRA and a standard angiography.
Alternatives to surgery can include chemotherapy, embolization and radiation.
If surgery is selected, surgeons access the skull base through the ear bone, at the temple beneath the brain, above the eye, through the nose or from the neck. Brain surgery is sometimes performed during the procedure as well. Surgeons take care to minimize the size of the bone opening to help ease recovery.
After surgery, it is necessary to reconstruct the layers covering the brain to prevent the leakage of brain and spinal fluid. Tissue from other areas of the body may be used to help with this reconstruction.