Burr Hole

What Is It?

A burr hole is a relatively small opening made in the bone of the skull to access the intracranial space (the space inside the skull). It is typically made by some form of spinning burr tool which can either be a manual, electric or pneumatic drill. The cutting bit is very much like a drill bit and allows the neurosurgeon to drill through the skull in a controlled fashion. Performing these holes may also be referred to as trephanation or trepanation and evidence of its use dates back into pre-history.

The size of a burr hole varies. Smaller burr holes may be used simply to introduce a catheter or biopsy needle into the brain. Larger burr holes may be required to drain various things from inside the head or as part of a larger operation. They may be performed singly or multiple holes may be made. For example, multiple burr holes may be connected together (by a different drilling tool) as in the creation of a craniotomy, a larger opening of the skull to operate on the brain or its surrounding structures.

Access to the skull to make the holes is usually by way of some opening in the skin of the scalp which is reflected to reveal the adequate portion of the skull to perform the drilling and subsequent procedures.

Because the bone is drilled away, the original bone is generally not returned after the procedure is done. Smaller holes may simply be left to heal with the scalp closed over it. Larger holes, and those that are in cosmetically important areas such as the forehead, are often covered with a metal (usually titanium) plate or bar which are fixed to the surrounding skull.

What Is It Used For?

Obviously, operating on the brain and its surrounding structures requires access to the inside of the skull, the bone enclosing the brain in the head. In order to do so, holes must be drilled in the skull. Therefore, some form of bur hole is often requires in most brain surgeries, whether small or large.

In its simplest form, a hole may be made in the skull to introduce a small device or tool into the brain. For example, when placing a ventriculostomy catheter, a deep brain stimulator or a biopsy needle (to take a small piece of tissue for pathology).

Larger holes may be used to drain blood from around the brain, such as in the case of treatment of subacute or chronic subdural hematomas (acute subdurals are more solid and usually require an open craniotomy to remove).

Finally, various other surgical procedures may be performed through a relatively small opening. For example, endoscopic procedures (which use a scope for visualization within the head) and some microsurgical procedures may only require a small opening. If larger access is needed, multiple holes may be connected together to remove a larger portion of skull, which is called a craniotomy.

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Important Note: This site is not intended to offer medical advice. Every patient is different, and only your personal physician can help to counsel you about what is best for your situation. What we offer is general reference information about various disorders and treatments for your education.

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