Burrholes are made by drilling single or multiple holes in the skull with a drill ("perforator").

This procedure is utilized to drain liquified collections under the skull (subdural hematomas, hygromas, empyemas), to introduce a biopsy needle (brain biopsy), to drain deep fluid collections (cysts, brain chambers), to insert an Intracranial Pressure (ICP) monitor, or to place a shunt catheter in the ventricle. They are sometimes made as an emergency to try to drain an epidural hematoma. Burr holes allow for drainage of liquified collections but cannot be utilized to remove solid lesions.

Burrholes may leave small dimples in the head which can be covered for cosmetic reasons, but are not considered to weaken the skull.