Arteriovenous fistulas (AVFs) can occur in many parts of the body and, depending on their size and location, they may be monitored without needing AVF treatment. But if a fistula affects areas near the brain or the spinal cord, intervention may be necessary to avoid serious complications that can include stroke and hemorrhage. Depending on their size, location and other factors, AVFs can be successfully treated by catheter embolization or microsurgical resectioning. In this post, we discuss common AV fistula surgery procedure steps.
AVF: Abnormal Connections Between Blood Vessels
Arteriovenous fistulas result from abnormal connections between veins and arteries. Normally, blood flows from arteries to veins via small vessels called capillaries. But when an AVF develops, blood flows directly from an artery to a vein, bypassing the smaller capillaries in the area. Blood vessels around a fistula can become diseased and die, or swell and break from too much pressure, causing blood to leak into surrounding tissues. The AV fistula surgery procedure steps taken by your neurosurgeon aim to remedy the blood vessels of this issue.
When AVF Affects the Brain
AVFs can occur in the dura mater, the tough tissue covering the brain or in the brain itself. This kind of fistula can cause symptoms that include pulsatile tinnitus, a distinct rumbling or rushing sound in the ears, along with headaches. Some fistulas can cause swelling and redness in the eyes. The eye pressure can go up. Memory and concentration can also be affected. If a large fistula develops in or near the brain, swelling or hemorrhage can trigger seizures or strokes.
When AVF Affects the Spine
If an AVF occurs near the spinal cord, swelling and pressure can cause a number of vague symptoms such as back and leg pain, or weakness and stiffness in the legs. This kind of AVF can also cause impotence or urinary and bowel problems.
What Causes an AV Fistula?
An arteriovenous fistula, or AVF, can have a number of causes. Some are congenital, or present from birth, although the cause of this type of fistula is not entirely clear. Others can occur as a result from surgery. Still others are caused by traumatic injuries, particularly those such as stab or gunshot wounds that pierce the skin where a vein and artery are located alongside each other.
An AVF can also be caused by infection, and it can develop in connection with chronic health conditions such as diabetes and immune problems as well. This kind of fistula can also be deliberately created to make dialysis easier for those with severe kidney disease.
Many are never diagnosed and, of those that are found, not all need surgery. But when symptoms become severe, surgical procedures include catheter embolization to seal the fistula and microsurgical resection to remove it. Knowing AV fistula surgery procedure steps can help you prepare for your procedure and recovery.
Preparing for a Catheter Embolization Procedure
Before a catheter embolization procedure, you can expect to undergo blood tests and imaging exams. During this time, it’s important to tell your doctors about any medications you take, including herbal supplements and vitamins, and inform them if you know of any past allergic reactions to contrast dyes, anesthetics or anesthesia. If you take aspirin, blood thinning medications or other kinds of drugs, you may be told to stop taking them for a period of time before the procedure.
You may be told not to eat or drink anything for several hours before the procedure. Since you can expect to remain in the hospital for at least 24 hours, make sure you pack a bag with essentials, and make arrangements to take care of daily routines while you’re hospitalized.
Catheter Embolization – Procedure Steps
For many people, catheter embolization is the first choice for treating an AVF in the brain or dura.
Embolization is a minimally invasive procedure, which means that the procedure steps vary greatly from a traditional, open surgery. Here, a catheter is inserted through a small incision into a blood vessel in the groin area and directed to the location of the fistula. Your surgeon then places an embolic or blocking agent, such as medical glue or other synthetic material, into the fistula through the catheter. This closes the fistula and prevents further swelling or bleeding.
Catheter embolization is done in a hospital setting. You may or may not be asked to stop taking certain medications such as aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) a few days before the procedure, and to avoid eating and drinking after midnight on the day of your procedure.
Most people who have catheter embolization can expect to leave the hospital within a day or so, but people with other health conditions or advanced age might need to stay longer for monitoring. Patients who undergo catheter embolization can usually expect to fully return to normal activities within five days or so. Symptoms caused by the AVF, such as pulsatile tinnitus, headaches or vision problems, generally disappear completely after the procedure.
Embolization can resolve the AVF and get blood flowing normally again. Your doctors will schedule follow-up exams to make sure the AVF is completely sealed.
Preparing for Microsurgical Resection
Surgery for removing an AVF is more invasive than an embolization procedure, and you can expect to remain in the hospital for a few days longer. Before the surgery, you’ll need to plan for your hospital stay. Make sure someone is available to take care of your daily routine at home, and have a bag packed with things you will need. Use this time to make arrangements for your post-surgery recovery too. Your doctors may ask you to stop taking certain medications — or they may prescribe new ones to take before the procedure.
As with any surgery, you may be told not to eat or drink after midnight before your procedure. The surgery requires general anesthesia, so it’s important to discuss with your doctors any allergies or problems you may have with anesthetics, substances such as latex or anesthesia.
Microsurgical Resectioning – Procedure Steps
In some situations, when catheter embolization isn’t appropriate, your doctors may recommend surgical resectioning to repair an arteriovenous fistula. This procedure closes off the fistula completely so that oxygenated blood can be directed normally through the veins and arteries.
If the AVF is located in the brain or the dura covering the brain, surgery involves a craniotomy — a procedure in which an incision is made in the skin to expose a part of the skull covering the area where the fistula is located. There, a portion of bone is removed to expose the dura. If the fistula is located in the vessels of the brain, an incision is made in the dura to reach it.
During surgery, your neurosurgeon works through a microscope to close the fistula off. That allows blood to flow normally and reduces pressure from the enlarged fistula. Once the AVF is closed, the bone segment is put back in place and may be secured with metal plates. The skin is then closed and stitched.
Resectioning surgery is done in a hospital setting under general anesthesia. To prepare for this procedure, you will be asked to stop taking medications such as aspirin, blood-thinning drugs or NSAIDs a few days before surgery, and to stop eating and drinking starting at midnight before your surgery day.
After the procedure, you may remain in the hospital for a few days for monitoring. You can resume normal activities in about two to three weeks. Headaches can persist for weeks or months after dural AVF surgery, but symptoms such as pulsatile tinnitus and vision problems typically resolve completely. Follow-up exams monitor progress, but AVFs that are removed surgically generally don’t return.
Risks of AV Fistula Treatments
Catheter embolization and surgical resection are both largely safe, effective treatments for an AVF, but they do have risks, some of which may be serious.
Catheter Embolization
Catheter embolization has risks of its own. This procedure involves the use of contrast dye to locate the AVF via real-time imaging, and these dyes can cause severe allergic reactions and potential kidney damage in sensitive people. Risks also include bleeding, bruising and infection at the incision site in the groin. Other risks include damage to blood vessels during treatment and bleeding and swelling at the incision site. Less common risks include stroke or neurological damage, depending on the location of the AVF.
Surgical Resection
Because surgical resection of an AVF is open surgery that may require a craniotomy, risks include infection, swelling and hemorrhage. Depending on the location of the AVF, other risks can include aneurysm, stroke or neurological deficits caused by swelling in the brain or tissues and damage to nearby nerves. The best choice for treating an AVF will depend on its size, location and factors such as your age and overall health.
Learn About Your Treatment
Arteriovenous fistulas have many causes and, depending on location and size, these abnormal fusings of arteries and veins can trigger symptoms ranging from mild to severe. Catheter embolization and microsurgical resectioning can successfully and safely resolve AV fistulas of the brain and spine. Knowing the AV fistula surgery procedure steps for your condition can help you prepare for treatment — and resume a symptom-free life.