Arteriovenous Malformations Treatment: Embolization and Resection Overviews

Before Your Procedure

• The Benefit of Having Two Procedures

• What to Expect in the Days Prior to the Procedure

• What to Expect The Day Of

Your Embolization Procedure

• Understanding Glue & Onyx Embolization

• Risks & Side Effects of Embolization

• Risks of Microsurgical Resection

Your Microsurgical Resection Procedure

• What Happens Immediately Before Surgery

• Who Is On The Surgical Team

• What Happens During AVM Microsurgical Resection Surgery

Recovery After AVM Treatment

• How Long Will I Be In The Hospital?

• How Long Will Recovery Be At Home?

• When Do I Follow-up With My Surgeon?

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Before Your Procedure

Prior to your procedure, you can expect to have multiple visits with your doctor, in which you will receive clear instructions on what you should do before your appointment, how to modify medications, what you can and cannot eat and what to bring with you to the hospital. Your doctor’s instructions may differ from this general guide and your doctor’s specific instructions should always be followed.

Why am I undergoing two separate procedures instead of just one?

Embolization procedures alone can rarely cure Arteriovenous Malformations (AVM) and are typically used in combination with other treatments, such as stereotactic radiosurgery or microsurgical resection. This guide covers an embolization followed by microsurgical resection and will not be discussing stereotactic radiosurgery.

Typically, you will undergo your embolization procedure at least one day before the neurosurgeon performs your microsurgical resection. This is because blood thinners are used during an embolization procedure, and this poses the risk of increased bleeding during surgery. This delay between treatments gives your body time to clear the blood-thinning medication and return to normal. Depending on the size of the arteriovenous malformation and its specific architecture, you may be asked to schedule multiple embolization procedures, sometimes called staged embolization procedures, before the actual resection of the AVM. There are typically, one, two or three stages. Whatever the number is for you specifically, the last embolization stage is done the day prior to the resection procedure.

What can I expect in the days prior to the procedure?

In the time before your procedure, your doctor will schedule a pre-procedure visit with you to ensure that nothing has changed since he or she last saw you. You will have similar consultations with your endovascular surgeon.  Before your embolization procedure and on your day of surgery, he or she will meet with you to review your medications, blood pressure and heart status.

It is important to note that your hospital will require you to have certain tests done within 30 days of your procedure to ensure that your health is not compromised in any way that would increase surgical risks. Your doctor will give you further instructions on which tests you need and where and when to have them done. These tests typically include:

• Blood tests
• Labs
• Urine tests (+/- pregnancy test)
• EKG
• Chest x-ray
• Confirmation from your general physician that your heart and lungs are in a condition to undergo major surgery

You will also likely be given food and liquid restrictions leading up to your surgery. Your doctor will give you exact instructions, but patients will commonly be asked not to chew gum, drink coffee or have anything to eat or drink after midnight the night before your procedure. However, your doctor may ask you to take your usual medication (if you are taking any) with a small sip of water. Make sure that you are well informed as to whether you are allowed to skip any medication dosages prior to your procedure. These are for your comfort and safety and it is vitally important that you follow these instructions exactly.

What should I expect the day of the procedure?

On the day of your procedure, take your morning medications as normal unless your doctor has told you otherwise. If you are diabetic, there will likely be modifications to your usual medications.

You need to take care to follow any directions regarding medication modifications very carefully, as they are for your comfort and safety. If you have any questions about your medications, be sure to ask your doctor beforehand.

If you are on liquid restrictions, your doctor will tell you if you can take a swallow of water with any pills that morning. If he or she hasn’t addressed this specifically, be sure to ask at your next appointment.

You will be asked to arrive at the hospital about two hours before your scheduled appointment. Arrive wearing comfortable clothing, as you will ultimately be given a gown to change into for your procedure. Be sure to bring additional comfortable clothes, your cell phone, a list of the medications you take, a notepad for questions, headphones, books or magazines and toiletries.

After checking into the hospital, you will change into the hospital gown and the staff will start you on an IV. They will bring you into the operating room, which tends to be chilly, but you will be given a warmed blanket to keep you comfortable. You will also receive:

• A blood pressure cuff
• Balloons on your legs, which inflate and deflate to prevent blood clots
• An oxygen monitor on your finger
• Heart monitors

Once you are settled, you will be given anesthesia and will be asleep within a few seconds. Your doctors will perform your embolization and you will recover and remain in the hospital until your microsurgical resection procedure, or you will be discharged home the following day if you are having one of those staged procedures.

Your Embolization Procedure

In simple terms, embolization is the use of a synthetic material to block blood vessels. Sometimes it can be curative and will be the only treatment necessary. This is if your arteriovenous malformation is small and easily accessible by a catheter.  In most cases, an embolization will help block blood flow through the vessels of your malformation, but won’t be able to completely shut down the rapid blood flow in that abnormal lesion, which will then be removed during your microsurgical resection. Slowing or reducing blood flow is an important help for the actual resection since less bleeding equates to safer surgery, and shorter operating times.

During an embolization procedure, a neurosurgeon inserts a catheter through a blood vessel in your groin, guides it to your AVM and inserts a material that will help close up the abnormal connection between the arteries and veins. This will help reduce the size of your AVM before surgery.

What materials are used in an embolization?

The type of embolization material used is determined by your anatomy as a patient. There are two basic and commonly used types of embolization material: glue and Onyx.

The goal is to block blood flow to a specific area of the brain to prevent excessive bleeding or to destroy malformed vessels. If you will be undergoing a glue embolization procedure, the steps are as follows.

• Anesthesia is administered.
• A catheter is inserted into the artery in your upper thigh and threaded to the affected area within the brain.
• A balloon may be inserted and inflated to temporarily block the flow of blood.
• The surgeon injects n-Butyl cyanoacrylate, shortened to NBCA (liquid glue) to block the blood vessel.

Onyx embolization is a similar procedure that blocks abnormal blood flow from the artery into the vein or reduces pressure. The material has slightly different properties allowing it to stay in a liquid form for longer periods of time, and thereby allowing the material to travel farther than glue would.

The steps of an Onyx embolization are similar to glue embolization but vary slightly.

• Anesthesia is administered.
• A microcatheter and wire are placed into a major artery near your groin.
• The catheter is then guided to the AVM using x-ray imaging.
• Liquid solvent followed by Onyx are injected into the area.
• The mixture is allowed to set and becomes solid and spongy.
• The catheter and wire are removed.

What are the risks and/or side effects of embolization?

The side effects from your embolization procedure vary. You can experience common side effects from anesthesia such as:

• Drowsiness
• Vomiting
• Nausea
• Constipation

Your team will do their best to ensure you are comfortable following your procedure. Other side effects include headaches and rarely seizures or stroke-like symptoms. Reducing high speed blood flow through a long standing lesion in your brain should be done slowly and over time, allowing the brain to adapt to the changes. This is another reason why embolization procedures are often staged.  If you experience any of the above side effects, be sure to let someone know and they will do what they can to assist you.

What are the risks of microsurgical resection?

There are three primary risks involved with microsurgical resection.

Infection

The first is infection at the surgery sites. If you have excessive pain, redness, swelling or pus at one of your incision sites or if you are experiencing a fever, follow up with your doctor right away. He or she will likely put you on a course of antibiotics, but this depends on your exact situation.

Neurologic Impairment

A second potential risk of microsurgical resection for arteriovenous malformations treatment is neurologic impairment following the procedure. Your team will take all possible preventative measures to mitigate any neurological complications, including the use of imaging software and perhaps neurophysiological monitoring.

Should you notice any neurological impairment beyond what is expected during recovery, be sure to discuss it with your doctor. This includes numbness or tingling, muscle weakness or spasms. While some issues may resolve on their own with time, further treatment or physical therapy may be necessary. Any sudden changes in your brain function such as a seizure,or stroke-like symptoms, weakness, numbness, speech issues, or visual issues,  are a medical emergency, even if transient, and you should contact 911 immediately.

Stroke

The final risk following microsurgical resection of your AVM is that of a stroke. Though the surgical removal of your AVM immediately reduces your risk of stroke due to your malformation, there is a chance, though small, of a secondary hemorrhage and stroke following your procedure.

A stroke is a medical emergency. If you experience any of the following symptoms, it is important to contact emergency services right away, even if they resolve on their own:

• Sudden severe headache
• Sudden loss of or blurred vision in one or both eyes
• Trouble walking, talking or understanding
• Difficulty swallowing
• Weakness, tingling or numbness, typically in one side of the body
• Confusion

Never wait to speak to your doctor if you feel like you are experiencing any symptoms that seem to be out of the ordinary. If it is to be expected, he or she will reassure you that what you are experiencing is part of the recovery process.

Your Microsurgical Resection Procedure

Your microsurgical resection procedure itself will take several hours. Though your doctor and hospital may operate slightly differently, the information below will help give you an overall idea of what your procedure will consist of.

What happens before the surgery?

Prior to your procedure, there is a time where the entire surgical team is in the room participating in what is called a huddle. This is where all the people involved will discuss everything about your upcoming procedure, including:

• A review of your information
• A rundown of the team that is in the room
• Confirmation of which side is being operated on
• A review of antibiotics and/or medications needed
• Any other pertinent information

In some hospitals, such as The Valley Hospital, there are dedicated neurosurgical teams, specifically created to perform your procedure, as well as any other neurosurgery treatments. This is an important benefit, as having a surgical team that has consistently worked together previously, allows members to know each other’s tendencies and anticipate their needs.

This dedicated neurosurgical team will not be the case at all hospitals.

How will I be positioned during the surgery?

Once you are under anesthesia, it can be very difficult for the surgical team to move you around. In fact, it takes a group of multiple people to properly position you, including the primary surgeon, two nurses, the endovascular surgeon, a scrub tech and nurse and the anesthesiologist. The anesthesiologist will guide the team as they position you into place, a process which can sometimes takes up a long time.

The reason the process can take so long is that you need to be positioned in a particular way to maximize your comfort, as well as provide accessibility to the surgical site. All points of your body will be touching soft surfaces, which may be sponges or gel boards. The endovascular surgeon will need to be able to access the groin area, and the head and groin area must both be accessible and sterilized separately.

Unlike some other neurosurgical procedures, your hair will not be shaved or cut. Instead, it will simply be parted out of the way and your head will be marked accordingly. The surgical team will also place temperature probes, which are responsible for monitoring your core body temperature at all times.

Who is on the surgical team?

During your procedure, there will be many people in the operating room. Each plays an important role as a member of your surgical team, ensuring your procedure goes smoothly. There may be variations at your hospital, but there will likely be people filling all of the following roles.

Primary and Assisting Surgeons

The first people are the main (primary) surgeon and the secondary (assisting) surgeon. Both surgeons are necessary and both have important roles. The primary surgeon will do most of the work during the actual surgery and the assisting surgeon will make sure everything is out of his or her way, maximizing access and visualization.

Surgical Technologists

There will also be two scrub techs, also known as surgical technologists or operating room technologists. The scrub techs assisting with your procedure will be neurosurgery-specific scrub techs who have received special training in assisting with neurosurgeries. Their role is to assist the surgeons by laying out all necessary equipment on a table before the procedure and handing them tools as needed.

Anesthesiologist

The anesthesiologist is the doctor who is responsible for administering your anesthesia and monitoring you during the entire procedure. Sometimes your neurosurgeon will have an anesthesiologist he or she typically works with who specializes in neurosurgical procedures. These specialized anesthesiologists are not always available, with some hospitals favoring a general anesthesiologist.

Anesthesiologist Tech

Similar to the scrub tech, there will also be an anesthesia tech. This person’s job is to assist the anesthesiologist specifically, bringing any necessary equipment to the surgery. For example, if a patient requires a blood transfusion, the anesthesiology tech will retrieve it and bring it to the operating room.

Circulating Nurses

There will be two circulating nurses in the room, both of whom play a vital role. While the surgeon, assisting surgeon and scrub techs are sterile, the circulating nurses are out of the sterile field. This means they can grab items outside of the sterile field, which includes anything other than what has been prepared for the surgery.

One nurse will be responsible for tasks such as straightening the bed, adjusting the heating blanket and keeping time. The other will provide documentation, logging everything during the surgery so there is a record, but can jump in to help as needed.

Brainlab Image Technician

Another person in the operating room is the Brainlab image technician. Brainlab is an imaging system used to visualize the brain and the Brainlab image technician is responsible for handling the specialized brain navigation equipment prior to and during the procedure. In some cases such specialized imaging techniques are not used. This depends on where the AVM is located.

Endovascular Surgeon

There will be another doctor in the room, the endovascular surgeon, who will perform the angiogram on your AVM. An angiogram is a video of the blood vessels, which shows the speed of the blood flowing through the malformation. The goal of the procedure is to completely remove the AVM. The angiogram is used to confirm that all the abnormal blood vessels are removed. In order to perform a high quality angiogram during surgery (intra-operatively), a very special operating room is needed.

Endovascular Scrub Tech

Similar to the neurosurgery scrub techs, there will also be a scrub tech working specifically with the endovascular surgeon. He or she will be responsible for handing instruments to the endovascular surgeon during the angiogram.

Endovascular Nurse

There is also an endovascular nurse present who does not operate within the sterile field. He or she is there to document the procedure and assist when it requires handling non-sterile materials. He or she will also compress the artery for 20 minutes after the angiography instruments are removed.

Neurophysiologist

Finally, there may or may not be a neurophysiologist present. This is a specialist who monitors neurological electricity through what is known as intraoperative neurophysiologic monitoring. This helps provide feedback to the surgeon by monitoring neural current to the left leg, alerting the surgeon during the procedure if there could be damage to a nerve.

What happens during the AVM microsurgical resection surgery?

During the surgery, the team will use brain navigation, which is a real-time image of the brain that helps the surgeons see exactly where they are in the brain, helping them visualize everything before making any incisions.

The angiogram images from the endovascular surgeon will be translated prior to and during surgery. This is another tool to provide surgeons assurance that they are making incisions in the appropriate places. At some hospitals, including The Valley Hospital, the angiogram machine is typically within the operating room, so you will not need to be transported from one room to another.

A craniotomy is necessary to provide the surgeon’s access to the brain. The procedure involves removing a small section of your skull, enough to provide adequate access, which will be replaced after the procedure. As discussed earlier, your hair will be parted out of the way and will not need to be shaved or cut.

Once the surgeons have access to your brain, they will isolate the AVM from the tissues around the brain using a special surgical microscope. Once there is an opening, they set up a microscope that has three viewing lenses, allowing three different people to visualize the field at once. This helps the surgeons see anything not visible with the naked eye.

At the start of the surgery, the surgeon will begin with goggles, and the images from the microscope will be transmitted onto a screen. If the surgeons need to use the microscope viewing lens, it is set up and available for up to three people to use at a time.

Along with the image from the microscope transmitted onto a screen, the surgical team will also have other information on the monitor. They will have three screens of information: the microscope screen, the angiogram screen and the Brainlab screen, which primarily serve to help the surgeons make the correct incisions.

The final step is for the surgeons to replace the section of skull that was removed during the craniotomy and close the incision sites. You will be monitored as you wake from your procedure and will be taken to the recovery area.

Your Recovery Following Arteriovenous Malformation Treatment

How long will I spend in the hospital?

The length of your total stay will depend on multiple factors, including your recovery from a lengthy anesthesia, and how long your surgeon would like to monitor your recovery. However, most patients can expect to spend a total of two to three days in the hospital.

How long will I recover at home?

Generally speaking, recovery at home takes about four to six weeks for most patients, during which you will have activity restrictions. You can expect to be able to resume most of your normal activities at about the six-week point, including returning to work, though your full recovery can take up to six months.

When you first return home, you will probably still be sore from your procedures and will require pain medication. As such, it will be helpful if you can arrange beforehand for someone to help you with errands, cooking, childcare and chores around the house.

For the first couple of days, you likely be tired and not up for much activity. As a few more days pass, you will be able to stay awake longer, walk around more and may find your appetite returning to normal. It’s important not to overtax yourself and only participate in activities your doctor has approved, including any lifting restrictions.

Following your surgery, you may have liquid intake guidelines, though you will most likely be able to eat any foods you like. You may find that your medications decrease your appetite, so stock up on easily digestible, bland foods prior to your surgery.

Depending upon your personal circumstances, you may also require physical therapy for any neurological deficits. This will be tailored personally to your condition and needs and not every patient will have physical therapy.

Finally, your physician will outline any changes you may need to make to medications you were taking before your procedure as well as prescribe new medications. Never modify any prescriptions on your own without consulting your physician. If your doctor does not give you a prescription for pain medication, be sure to ask him or her before taking anything over-the-counter for pain.

You may also be given prescriptions for medications that help with headaches and help to prevent brain swelling and seizures following surgery. It is important you take these exactly as directed by your doctor, who will follow up and monitor their effectiveness. Do not stop taking these medications without consulting your doctor, even if you feel like they upset your stomach.

What follow-up visits can I expect?

Your first follow-up visit actually occurs during surgery, when the endovascular surgeon performs an angiogram to ensure that all the AVM has been removed and that the surgery has been successful. You will be still under anesthesia during that time.

Approximately seven to ten days after your procedure, you will need to return to have staples removed from the craniotomy site. At this visit, your doctor will check for further complications, including:

• Fluid accumulation
• Hemorrhages
• Blot clots

If he or she suspects any of these complications, then you may require further imaging of your brain to assess the situation and determine whether or not treatment is required.

Finally, approximately one year following your procedure, you will be scheduled for a follow-up MRI of your brain to assess your recovery. Your doctor may arrange for other follow-up visits as well, depending upon your individual condition.

Preparation Contributes to Peace of Mind

Your upcoming AVM treatment and hospital stay can be a less stressful experience just by taking the time to prepare yourself beforehand. Self-education is a great way to have a better understanding of what will be happening when you arrive at the hospital, during your surgery and when you get home. By knowing what to expect, you will encounter fewer surprises and be able to focus more wholly on resting and recovering.

You may find it helpful to prepare a to-do list before your procedure, using this guide as an outline. Some steps you may wish to take include:

• Writing a list of questions to ask your doctor at your next appointment
• Developing your list of current medications and consulting your doctor about any modifications to be made before and after your procedure
• Stocking up on items you will need during your recovery at home, including comfort foods, toiletries and other essentials
• If you live alone, arranging to have someone come by at least once daily following your procedure to help you with chores or errands
• Deciding what you will be bringing to the hospital and packing your items beforehand.

The procedures outlined here may not be exactly the same as your hospital’s methods. Any directions from your doctor take precedence and if you have questions along the way, be sure to ask them. This guide can help serve as a jumping-off point for your next conversation with your doctor and he or she will be happy to answer any questions you may have.