The NeuroMedical Center | Patient Education Library | Burr Hole Drainage

This procedure creates one or more holes in the skull to release excess fluid pressure in the brain caused by a chronic subdural hematoma (blood clot on the brain.) It can be performed under local anesthesia.


A portion of the head may be shaved, and the scalp is numbed with injections of local anesthesia. The patient is often mildly sedated during the injections.

Accessing the Brain
The surgeon makes a tiny incision in the scalp and drills one or two tiny holes  through the skull, exposing the dura (the protective membrane around the brain). The dura is then opened with a small scalpel.

Draining the Fluid
The opening allows the fluid to drain from inside the skull, reducing pressure. Saline may be injected to help wash out the fluid.

End of Procedure and After Care
The wound is closed with sutures (in some cases, the surgeon may need to place a drain in the hole so that the fluid can continue to flow). The patient
will continue to be closely monitored.