To diagnose brain lesions, a commonly used procedure is a Stereotactic Brain Biopsy. During this operation, a small piece of tissue from the brain, scalp, blood vessels, or dura mater will be taken. Usually patients will come to a physician with symptoms that need brain imaging to reveal lesions of unknown causes. A brain biopsy may be needed to get tissue to be reviewed for a complete diagnosis. Stereotactic equipment is often used to find the siet for the brain biopsy to be taken. The neurosurgeon is able to look at the brain in a 3D system and evaluate the coordinates to move the biopsy needle.
Around 30,000 people are affected by pituitary brain tumors every year. Around 200,000 people are affected by metastatic tumors every year. Glioma and meningiomas are the most frequent primary brain tumors people develop. An MRI can provide insight to the size and placement of the tumor. An MRS, magnetic resonance spectroscopy, can give information on the chemical makeup of the tumor. Diffusion or perfusion weighted imaging tells about the flow of blood and water though a tumor.
The most complete diagnosis can be made when a tissue sample is taken. The neurosurgeon will decide whether a biopsy should be done or if a tumor removal operation should be done. If a biopsy is the path the neurosurgeon recommends, then the most safe and precise route will be taken to get to the tumor. Metastatic brain tumors often need a biopsy to confirm a diagnosis.
STEREOTACTIC SURGERY
Stereotaxis is how neurosurgeons use imaging such as CT scans or an MRI, algorithms, and a computer workstation to accurately find the location of a tumor or a lesion in the brain. This used to be done by a metal frame that was put on the head of the patient. This has been changed by a system that will use nickel size markers placed on different regions of the scalp. Stereotactic navigation systems are systems that use stereotaxis to assist neurosurgery operations. They are usually called frameless stereotactic neuronavigation systems because the metal frame is not used much. This might be used to assist a neurosurgeon during surgery such as a biopsy.
Different biomedical engineering companies will make frameless stereotactic neuronavigation systems and all are similar in pros and cons. A stereotactic biopsy is done inside of an operating room and under general anesthesia. A quarter-size burr hole is made to open the skull and the dura is opened. A needle is brought to the target using the neuronavigation system to guide it and biopsy samples are taken.
TECHNIQUE
The patient’s head will be secured while he or she is asleep. The fiducials on the scalp are put into a computerized navigation system. Some hair is shaved off and a small incision will be marked. The area is carefully cleaned and will be draped. A quarter-size burr hole is made to open the skull and the dura is opened. A needle is brought to the target using the neuronavigation system to guide it and biopsy samples are taken.
A frozen section analysis will allow a pathologist to examine these in normal time and then more samples are taken for permanent pathology studies. It can take around three or four days for special stains to be done. Once the incision is closed, a clean dressing is put on and this can be removed about a couple of days. A patient may require an overnight stay in the hospital. The sutures are taken out in 10-14 days.
INDICATIONS
Tumors, infections, inflammation, demyelinating diseases, and neurodegenerative disease are often diagnosed with a biopsy. This biopsy can be helpful in examining and identifying lesions that are not surgically treatable.
BENEFITS
A needle biopsy is helpful because the neurosurgeon can get a specimen from the deep parts of the brain safely. Hospitalization stay is very brief after with a possible overnight stay.
RISKS
There are risks that come with a stereotactic biopsy. This can include intracranial hemorrhage (1%) or infection (1%). This is generally a safe and helpful operation to help with further treatment and diagnosis. The equipment is high quality so there is very high accuracy which is less likely to damage nearby tissues.
RECOVERY
Bandages might be put over the incision spot and can be removed the next day. Sometimes patients are kept overnight in the hospital. There might be a little bit of tenderness near the incision site. Most people can go to normal and daily activities the following day.
FOLLOW UP
A follow up will most likely be placed based on the results of the biopsy. If there is an infection that an infectious disease specialist may be called.
