Brain surgery is used to treat a variety of conditions, such as tumors, blood clots, aneurysms, epilepsy, and Parkinson’s disease. It is performed by a neurosurgeon and involves an anesthesiologist with extensive knowledge of the types of anesthesia, monitoring, and post-operative care required for these sensitive operations. In some cases, this anesthesiologist will be a neuroanesthesiologist who has received advanced clinical training in anesthesia for brain and spinal surgeries.
These are some of the most common operations involving the brain or areas around it. Some of the explanations below are derived from information obtained from the National Cancer Institute.
- Craniotomy. A piece of the skull is removed to give doctors access to the brain to remove a brain tumor, abnormal tissue, blood, or blood clots; relieve pressure after an injury or stroke; repair a brain aneurysm or skull fractures; or treat other brain conditions. The piece of the skull is put back in place after surgery.
- Biopsy. Biopsies are typically done after imaging has detected a potential abnormality. The surgeon makes an incision in the skull or inserts a needle to remove brain cells or tissue for examination by a pathologist.
- Deep brain stimulation (DBS). A battery-operated medical device called an implantable pulse generator is implanted to deliver electrical stimulation to specific areas in the brain. DBS is most commonly used for movement disorders like Parkinson’s disease.
- Neuroendoscopy. This minimally invasive technique involves threading a thin tube called an endoscope through the mouth, nose, or small incisions in the skull to access or remove brain tissue. The endoscope has a light and camera on the end, and the surgery is performed with tools placed through the endoscope. Endoscopic transsphenoidal surgery (also called endoscopic pituitary surgery) is one type of neuroendoscopy. It involves threading the endoscope through the nose to remove brain tumors and lesions near the pituitary gland, just behind the bridge of the nose.
- Posterior fossa decompression. This treatment involves parts of the brain called the cerebellum and brainstem. For example, to treat a Chiari malformation, the surgeon makes an incision at the back of the patient’s head to remove a small portion of the bone at the bottom of the skull. This removal creates more space for the cerebellum and relieves pressure on the spinal cord.
- Thrombectomy and cerebral aneurysm repair. The surgeon guides surgical instruments such as a catheter or thin metal wires through a large blood vessel in the patient’s groin to reach the brain vessels, using contrast dye to identify the problematic blood vessel without opening up the skull. The procedure is most commonly used on patients with a blood clot in a brain artery, a cerebral aneurysm (a weakened and bulging area in an artery wall) or a ruptured aneurysm that causes bleeding into the brain.
Some brain cancer patients are treated with stereotactic radiosurgery, which may include use of a Gamma Knife, but this is not a surgery in the common understanding of the term, and the “knife” is not actually a knife. Radiosurgery is an external radiation treatment that does not involve an incision. Special equipment, like the brand-name Gamma Knife, precisely delivers a high dose of radiation that targets tumors or other lesions, minimizing damage to surrounding healthy tissue.
Anesthesiologists play a critical role before, during and after the operation to help enable the best outcome and recovery.
- For nonemergency surgery, an anesthesiologist typically will meet with you days before or the day of your surgery to explain the anesthesia care, risks, and side effects. The anesthesiologist will review your medical history and diagnostic tests, ask about prior reactions to anesthesia and advise you on which of your medications you should stop or continue taking in the days leading up to the operation.
- The information gathered during this appointment will help the anesthesiologist choose medications that will provide safe and effective anesthesia while creating the least possible interference with the surgical procedure.
- Before surgery, the anesthesiologist may explain how your condition will be monitored during the operation (e.g., using EEGs, EKGs, catheters) and what is likely to happen afterward, such as whether you may need to spend time in the intensive care unit.
- During the operation, the anesthesiologist will monitor all vital functions, as well as nerve and muscle responses. Your anesthesiologist will also work to maintain healthy brain blood flow, blood pressure, and oxygenation levels, in addition to providing pain control.
- After the procedure, the anesthesiologist may provide medications to address potential side effects of brain surgery, such as seizures or nausea. Anesthesiologists are also experts in pain management and can determine the best options for pain relief, as needed.
General anesthesia is frequently used and is especially important for high-precision tumor removal because you must remain absolutely still. Under general anesthesia, you will be unconscious throughout the operation.
Some surgeries are done under monitored anesthesia care or sedation. You receive medicines to relax you and block pain, but you remain either conscious or in an unconscious state from which the team can easily wake you when necessary during surgery. This allows for direct feedback from you, which can be extremely important. This is often referred to as “awake” surgery and is discussed in more detail below.
Awake brain surgery is primarily used for operations to treat epileptic seizures and Parkinson’s disease, but it is increasingly used for removal of brain tumors near portions of the brain that can affect critical functions. Remaining conscious allows you to answer questions that can help the surgeon identify areas of the brain affecting functions like vision, movement, or speech. The surgeon uses that information to precisely target the treatment.
In awake brain surgery, you still receive sedation and pain relief medication from your anesthesiologist, who will monitor your blood pressure, heart rate, and oxygenation and always remain at your side. In addition, your surgeon may give you a local anesthetic to numb your scalp.
You will not necessarily be fully aware or conscious during the entire procedure. The anesthesiologist can adjust levels of medication during surgery to wake you only at necessary times. Even then, you may not need to be brought to a state of full consciousness in which you can speak. Instead, you may be brought to a state in which you can respond by squeezing a hand or giving some other signal. Some patients do not even remember they were awake.
Preoperative discussions with your anesthesiologist can help reduce any anxiety you might feel about this type of surgery.
Anesthesiologists are also pain management specialists for conditions related to surgery. Before the operation, the anesthesiologist may ask about your pain tolerance to help gauge how best to manage any post-operative pain, guiding decisions such as the proper narcotics dosage and the feasibility of nonnarcotic pain relief medication. The anesthesiologist will consult with you after surgery and may adjust your treatment based on the level of pain you are experiencing.
The anesthesiologist will also consider factors such as a pain medication’s potential impact on oxygenation and breathing during your initial recovery or on your ability to interact promptly during the post-operative assessment of your neurological status. This weighing of benefits and risks is especially important for pain relief medication taken during the first 24 hours after any major neurosurgical procedure.
Anesthesiologists are the most highly skilled medical experts in anesthesia care, pain management, and critical care medicine. They have the education and training that, in some circumstances, can mean the difference between life and death.