burrhole

A burr hole is a small opening drilled through the skull using a high-speed surgical drill with a burr or trephine. The hole is usually 8 to 30 millimeters in diameter and is intended to provide access to the intracranial space for diagnostic or therapeutic purposes. Burr holes are less extensive than a craniotomy, which involves removing a larger bone flap; sometimes several burr holes are made to reach a specific area or to place multiple devices.

Indications for burr hole procedures include drainage or evacuation of intracranial hematomas (such as acute subdural or epidural hematomas), placement of external ventricular drains or intracranial pressure monitors, biopsy of brain tissue, and insertion of monitoring electrodes for neurological assessment or stimulation. The technique is used in various settings, including emergency trauma care and planned neurosurgical interventions, and may be performed under local anesthesia with sedation or general anesthesia depending on the case.

Complications can include infection, bleeding, injury to the brain or surrounding vessels, pneumocephalus, seizures, or wound issues. Postoperative care focuses on infection prevention, observation for signs of neurologic change, and managing intracranial pressure. The bone edges may heal over time, and some patients require later cranioplasty to restore the skull more fully.

The term burr hole derives from the cutting burr used to create the opening; trephination is an older term for skull perforation. Burr holes remain a fundamental, less invasive option in modern neurosurgery for access and management of intracranial conditions.