Being able to definitively diagnose a mass detected within the brain is the most critical step in treatment planning. Not every brain mass may be suitable for surgical removal; the location and size of the mass, or the patient’s general condition, may not permit open surgical intervention. At this point, stereotactic brain biopsy comes into play as an indispensable diagnostic tool in neurosurgical practice.
In this article, I will try to explain what a stereotactic brain biopsy is, in which situations it is preferred, how the procedure is performed, and to answer the fundamental questions our patients wonder about.
What Is Stereotactic Brain Biopsy?
Stereotactic brain biopsy is the procedure of taking a sample from the target tissue within the brain through a small hole (burr hole) opened in the skull, using a computer-assisted coordinate system. The term “stereotactic” means determining a point in three-dimensional space with millimetric precision. Thanks to this method, the surgeon can take a tissue sample by reaching the lesion in the brain via the shortest and safest route.
The obtained tissue sample is examined in the pathology laboratory, and the type, grade, and molecular characteristics of the mass are determined. This information plays a decisive role in creating a patient-specific treatment plan—chemotherapy, radiotherapy, targeted therapy, or observation.
In Which Situations Is Stereotactic Biopsy Performed?
Stereotactic brain biopsy is frequently preferred in the following clinical scenarios:
Deep-seated lesions: It is ideal for masses in regions that are risky to reach with open surgery, such as the thalamus, basal ganglia, and brainstem.
Lesions in eloquent (functional) areas: In masses located close to the speech, motor, or vision centers, biopsy offers a safe alternative in cases where open surgery carries a risk of neurological damage.
Multifocal lesions: When lesions are detected simultaneously in more than one region of the brain, it may not be possible to remove all of them. A sample is taken from the most suitable lesion for diagnostic purposes.
Patients whose general condition is not suitable for surgical resection: It is preferred in patients who cannot tolerate a major surgical intervention due to advanced age, accompanying systemic diseases, or a low performance score.
Suspicion of lymphoma: In cases where primary central nervous system lymphoma is suspected, since the treatment approach is chemotherapy and radiotherapy rather than surgery, a biopsy is sufficient to confirm the diagnosis.
Lesions for which a definitive diagnosis cannot be made radiologically: In cases where MRI imaging findings cannot distinguish between infection, demyelinating disease, tumor, or radionecrosis, a histopathological diagnosis becomes mandatory.
Pre-Procedure Preparation
Patients scheduled for a stereotactic biopsy undergo a comprehensive evaluation before the procedure:
First, an up-to-date, thin-section brain MRI is performed. In addition to contrast-enhanced and non-contrast series, MR spectroscopy, diffusion, and perfusion studies are also obtained when deemed necessary. These images are of critical importance for accurately determining the target and for path planning.
Coagulation parameters are checked with blood tests. Patients using blood-thinning medications must discontinue these medications appropriately within a period determined by the surgeon.
A preoperative evaluation is performed by the anesthesia team. The procedure can be carried out under general anesthesia or with sedation accompanied by local anesthesia; this decision is determined according to the patient’s condition and the surgeon’s preference.
How Is the Procedure Performed?
Stereotactic brain biopsy is currently performed using two fundamental methods:
Frame-Based Stereotaxy
This is the classic and gold-standard method. A metal frame (stereotactic frame) fixed at four points is attached to the patient’s head under local anesthesia. While the frame is in place, a computed tomography (CT) or MRI scan is taken. Target coordinates are calculated on these images, and the entry point, angle, and depth of the needle are determined to the millimeter using surgical planning software.
In the operating room, a hole approximately 1 cm in diameter (burr hole) is opened in the skull. The biopsy needle is directed to the calculated coordinates via the arc system on the frame, and several samples are taken from the target tissue. The procedure generally lasts between 45 and 90 minutes.
Frameless Neuronavigation Method
In this method, which has become widespread with the advancement of technology, no frame is attached to the patient’s head. The MRI images taken before surgery are uploaded to the neuronavigation system in the operating room environment. By matching the patient’s superficial anatomical reference points with the images (registration), the surgeon is able to monitor the needle position on the screen in real time.
Both methods have a high accuracy rate. Target accuracy is at the level of 1–2 mm in frame-based systems and 2–3 mm in frameless systems.
The Post-Procedure Process
Following the biopsy procedure, the patient is kept under close observation for a few hours. A control brain CT is usually taken 4–6 hours after the procedure to evaluate for possible bleeding.
Most patients can be discharged within 1–2 days after the procedure. Mild headache is considered normal and can be controlled with simple painkillers. The small skin incision at the procedure site is usually closed with a few stitches, and the stitches are removed after 7–10 days.
The pathology result for a standard histopathological examination usually comes out within 5–7 business days. When molecular tests are required, this period may extend to 2–3 weeks. After the result is obtained, the patient’s treatment plan is evaluated in a multidisciplinary tumor board (brain tumor council), and the final treatment strategy is determined.
Risks and Complications
As with every surgical intervention, stereotactic biopsy also has certain risks; however, these risks are markedly lower compared to open brain surgery.
Bleeding (hemorrhage): This is the most important complication. The rate of clinically significant bleeding is reported in the literature to be between 1–3%. Careful path planning that avoids vascular structures minimizes this risk.
Infection: Seen in less than 1%. The risk is kept low with sterile technique and prophylactic antibiotic administration.
Neurological deficit: If the needle path passes through critical structures, temporary or permanent neurological loss may occur. This risk is at quite low levels thanks to modern planning software.
Diagnostic insufficiency: The probability that the obtained tissue is not diagnostic is between 5–10%. In this case, a repeat biopsy or alternative diagnostic methods may come onto the agenda.
Frequently Asked Questions
“Will I feel pain during the procedure?”
In procedures performed under general anesthesia, you will not feel any pain. In cases where local anesthesia is preferred, there may be a brief stinging sensation only during the first numbing injection; apart from this, the procedure is carried out painlessly.
“Will my hair be completely shaved?”
No. Only a limited shave is performed around the small area where the procedure will be carried out. There is no hair loss over the majority of the head.
“When can I return to my daily life after the procedure?”
After an uncomplicated biopsy, the vast majority of our patients can return to their daily activities within 3–5 days. It is important to follow your surgeon’s recommendations regarding heavy physical exertion and driving.
“Does a biopsy cause the mass to spread?”
This question is frequently asked by our patients. Current scientific evidence does not show a significant risk that stereotactic biopsy causes tumor spread.
Conclusion
Stereotactic brain biopsy is one of the cornerstones of neurosurgical practice with its minimally invasive nature, high diagnostic accuracy, and low complication rate. Obtaining a correct diagnosis of a mass within the brain is the precondition for receiving the correct treatment. Every patient is unique, and treatment decisions should be evaluated individually by an experienced team.
Patients who have been diagnosed with a brain mass or who have concerns about this matter can obtain detailed information by contacting our clinic.
This article has been prepared for general informational purposes and does not replace medical diagnosis or treatment. Always consult your physician for your individual health decisions.
Prof. Dr. Mehmet Şenoğlu Brain and Nerve Surgery Specialist
References:
Bernays RL, Kollias SS, Khan N, Brandner S, Meier S, Yonekawa Y. Histological yield, complications, and technological considerations in 114 consecutive frameless stereotactic biopsy procedures. Journal of Neurosurgery. 2002.
Dammers R, Haitsma IK, Schouten JW, Kros JM, Avezaat CJ, Vincent AJ. Safety and efficacy of frameless and frame-based intracranial biopsy techniques. Acta Neurochirurgica. 2008.
Meshkini A, Shahzadi S, Alikhah H, Naghavi-Behzad M. Role of stereotactic biopsy in histological diagnosis of multiple brain lesions. Asian Journal of Neurosurgery. 2013.