Rarely defects or separations in the bone surrounding the skull can allow a small part of the brain to pouch out of the skull. This is called an encephalocele. This can happen in the bone around the ear called the temporal bone. Sometimes an encephalocele can be associated to a cerebrospinal fluid leak as well. Encephaloceles may be associated trauma or prior surgery. However many times the formation of encephaloceles are spontaneous occurring.
Temporal bone encephaloceles are often diagnosed with imaging. Both CT and MRI may play a role in making the diagnosis. Sometimes encephaloceles are found unexpectedly at the time surgery.
Encephaloceles of the temporal bone are treated similarly as cerebrospinal fluid leaks of the temporal bone. In smaller cases the encephalocele possibly can be treated through the mastoid bone. The tissue that extends into the temporal bone no longer functions, and is often removed. Various tissues and tissue-substitutes are used to repair the exposed area and help prevent the recurrence of the encephalocele. Larger defects or deeper areas may need a window of bone above the ear (craniotomy) in order to reach and repair the encephalocele.