A brain biopsy removes a very small sample of tissue so a pathologist can identify exactly what a lesion is. In a stereotactic needle biopsy, your MRI or CT images are combined with computer guidance to aim a thin needle at a precise point in the brain through a small opening in the skull. It is a much smaller operation than a craniotomy.
Guidance can be frame-based, using a rigid frame fixed to the skull, or frameless, using navigation registered to your own anatomy. A 2021 review of 20 studies and more than 3,200 biopsies found the two approaches give essentially the same diagnostic yield, about 93%.
A biopsy is advised when scans alone cannot say what a lesion is, when the tissue type will change the treatment plan, or when a tumor needs to be told apart from an infection or inflammation. It is often preferred for lesions that are deep, are in more than one place, or sit in areas where open surgery carries more risk.
Symptoms that lead to the imaging in the first place include new or persistent headaches, seizures, weakness or numbness on one side, balance problems, vision changes, and changes in memory, thinking or personality.
The procedure is done with sedation or general anesthesia and usually takes one to two hours. Most patients stay one night for monitoring. A first impression of the tissue may come back quickly, but the complete answer normally takes several days to a few weeks, because modern diagnosis includes molecular testing, not just what the tissue looks like under a microscope.
Bleeding at the biopsy site is the main risk. Most bleeding is small and causes no symptoms. Less common risks include temporary neurological symptoms, brain swelling, seizure and infection. Risk depends a great deal on where the lesion sits and on your overall health, so ask your surgeon what the numbers look like in your situation.
Will my head be in a frame? Not necessarily. Frameless navigation is as accurate for diagnosis as the older frame-based method.
How large is the incision? Small. The opening in the skull only needs to be wide enough for the biopsy needle.
Why not remove the whole lesion? Sometimes that is the better plan. But some conditions, such as lymphoma or infection, are treated with medication rather than surgery, so the diagnosis has to come first.
Sources: Mayo Clinic; Johns Hopkins Medicine; American Association of Neurological Surgeons; systematic review of frame-based versus frameless biopsy (2021).
To discuss a brain biopsy with our neurosurgeons in Lake Worth or Jupiter, call (561) 433-4444. Related: brain tumors and brain tumor surgery.
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