Burr Hole

A burr hole (from Fr. fraise — a cutting and drilling tool, and Eng. burr hole — a drilled hole) is a small, precisely round opening in the bones of the skull cap, which is formed by the neurosurgeon using a special medical drill. This is a fundamental technique in neurosurgical access.

Etiology and pathophysiology

This hole serves as the initial stage of a craniotomy or as a standalone access in minimally invasive endoscopic surgery. The diameter of such a hole usually ranges from 10 to 15 mm.

Automated pneumatic or electric trepans are used to create it. The instrument is equipped with a special safety mechanism (a clutch): as soon as the drill penetrates the diploe part of the bone and touches the internal cortical plate, it stops instantly. This completely eliminates the risk of accidental damage to the dura mater and brain injury.

Clinical significance

In modern neurosurgery, the burr hole as a standalone access is the gold standard for the surgical treatment of chronic subdural hematomas. Since the old hematoma consists of liquefied blood, it can only be drained through a small burr hole. The surgeon creates one or two burr holes, opens the dura mater, and washes out the liquid blood with warm saline, after which a thin drain is inserted.

Additionally, burr holes are used for emergency cerebrospinal fluid drainage (ventricular drainage), intracranial pressure monitoring, and deep brain tumor biopsies. The wound is closed with one or two stitches, and the bone defect subsequently heals with dense scar tissue or is covered with a tiny titanium plate.