The choice of treatment for brain arteriovenous malformations (AVMs) is very individual and will depend on the AVM’s complexity, how easy it is to reach surgically and whether removing it would run the risk of interfering with vital brain functions.
In addition to treating the brain AVM itself, Boston Children’s Hospital addresses any neurological symptoms it may have caused, referring patients to physical therapists, occupational therapists or speech and language therapists as needed and providing close support to help children and families cope with any resulting disability.
At Boston Children’s Hospital, the usual approach to AVMs is to attempt surgical removal if feasible and safe.
If your child is having surgery for an AVM, plan to spend about four hours in the pre-operative clinic to meet with nurses, the anesthesiologist and the neurointerventionalist. You will receive instructions ahead of time on how to prepare.
- Children can bring a favorite toy or blanket into the procedure room, and parents can stay close by, in the family waiting area, while procedures are being performed. Parents are welcome to stay with their children in the recovery room, the ICU and the hospital floor rooms afterward.
- If the AVM is complex, especially if it is supplied by deep, hard-to-reach vessels, we may recommend endovascular embolization (see below) as a separate step before operating.
- After the operation, we perform an additional angiogram before waking the child from anesthesia, to verify that the entire AVM has been removed. This is important, because even a small portion of the AVM left in the brain can pose a risk of bleeding.
Endovascular embolization is a minimally invasive, catheter-based technique that seeks to close off as much blood flow as possible to the AVM. By itself, embolization is rarely curative for AVM, but it can make surgery easier and safer, decreasing blood loss and providing a clean field for the surgeon’s operation.
Embolization is performed under general anesthesia by a neurointerventionalist with the help of specialized anesthesiologists, nurses and technologists and x-ray guidance. Parents will receive instructions on how to prepare ahead of time.
- The neurointerventionalist inserts a catheter (a thin, flexible tube) into an artery in the groin through a tiny incision, then advances it up the aorta (the main artery in the middle of the body) and guides it to the AVM. The catheter injects a specially designed medical glue, filling as much of the nidus (the area where veins and arteries connect) as possible.
- In some cases, embolization and surgical removal can be performed on the same day, but in most cases, the child will have embolization first, stay overnight in the ICU, and then have surgery the following morning.
- Most children have no pain or other symptoms with embolization. Though there are some serious risks, complications are rare.
- Embolization requires exposing patients to ionizing radiation (x-rays). Because children are more sensitive to radiation exposure than adults, we have adjusted our equipment and procedures to deliver the lowest possible dose.
When traditional surgery is too risky because the brain AVM is hard to reach or is in an “eloquent” area of the brain (with vital functions such as language), our team may recommend radiosurgery. Most often used to treat hard-to-reach brain tumors, stereotactic radiosurgery involves no incisions. Instead, the radiosurgeon aims a beam of high-energy radiation at the AVM.
- The tightly focused radiation—generated by a linear accelerator, a proton beam or a gamma knife—is precisely guided by 3D images and computer calculations. As a result, nearby tissues are minimally affected.
- After treatment, the abnormal blood vessels gradually wither and close down.
- Stereotactic radiosurgery generally takes 30 minutes to two hours. Children can often go home the same day or after an overnight stay.
Preparation and follow-up for AVM treatment
If your child is scheduled to come to Boston Children’s, you will receive specific information on how to prepare. Because these procedures involve general anesthesia, we usually ask patients to refrain from eating, drinking and sometimes from taking medicines for a certain period of time.
After treatment, most children leave the hospital within a few days. Sometimes, if the situation warrants, we will admit the child to the ICU for several days of observation. Children then return for a follow-up office visit within a few weeks of discharge.
We also perform a follow-up angiogram one year after surgery to verify that there is no residual or recurrent AVM. If this angiogram is “clean,” we then follow patients with MRI scans, at first annually, and then less frequently. Follow up may be in part through video teleconference for patients who live outside the Boston area.