A brain biopsy is a procedure used to remove a tumor or a piece of tissue from the brain so that it can be examined under a microscope to diagnose illness.
Types of brain biopsies include needle biopsy, stereotactic biopsy, and open biopsy.
In a needle biopsy, a small hole is drilled into the skull. A narrow, hollow needle is placed into the incision to extract a tiny portion of the tumor or tissue.
A stereotactic biopsy uses three-dimensional imaging technology, as well as data from CT and MRI scans, to examine a tumor or a piece of the brain. This procedure is minimally invasive. Patients can often tolerate it under light sedation, as opposed to general anesthesia.
Open biopsies are the most common form of brain biopsy. During the procedure, a surgeon removes a piece of bone from the skull while the patient is under general anesthesia. The tumor is exposed and removed. This is riskier than the other brain biopsy methods and requires a longer recovery time.
Doctors usually order brain biopsies to determine whether a tumor is cancerous or benign. It can also be used to diagnose dementia-related disorders such as Alzheimer's disease or Creutzfeldt-Jakob disease. Inflammatory disorders and multiple sclerosis can also be identified with brain biopsies.
A brain biopsy is generally seen as a last resort for diagnosing an illness. It is performed after imaging techniques prove inconclusive. In the case of dementia, the results may point to an illness that cannot be treated. Researchers have reported that the procedure may become more worthwhile for diagnosing dementia patients as new therapies are discovered (Warren, J.G., et al., 2005).
Brain biopsies are performed in hospital operating rooms. Sometimes a head ring is placed on the patient and held in place with pins. In some cases, a CT scan or an MRI is taken in conjunction with the biopsy, often with the head ring in place. In other cases, the CT or MRI scan is taken before the biopsy and the results are uploaded on to surgical equipment. This eliminates the need for a head ring.
In needle or stereotactic biopsies, a small incision a few millimeters long is made. After a tiny hole is drilled into the skull, a small needle with a light and a camera is placed into the brain and the biopsy is obtained. The doctor can navigate during surgery by watching a monitor.
After surgery, the incision is stapled or sutured. In the case of open biopsies, the bone flap is replaced with plates or wires. If there is swelling or infection, the flap is not replaced. This is called a craniectomy.
A brain biopsy can help doctors diagnose brain illnesses. This allows them to devise treatment plans.
Brain surgery is always risky, but needle and stereotactic biopsies are less invasive than open biopsies. They also have fewer complications.
Sometimes, tests on the sampled tissue are inconclusive and the procedure must be repeated.
Going under anesthesia always poses risks for elderly patients and people with dementia.
All types of brain biopsies can result in swelling or bleeding on the brain. They can also lead to infections, seizures, stroke, or coma. The risks have been reduced with modern technology such as stereotactic equipment.
Before the surgery, laboratory work and a CT scan or an MRI may be ordered. The doctor may discontinue the use of blood thinners and aspirin. The patient may need to wash his or her hair with a special shampoo the night before the surgery.
In some cases, particularly with stereotactic and needle biopsies, the patient may go home on the same day. Usually, a one-day hospital stay is required. The hospital stay may be longer depending on the health of the patient and whether any complications arise during surgery.
Written by: David Heitz
Medically reviewed by George Krucik, MD, MBA