For dural arteriovenous fistulas, a team approach
Date: April 30, 2012
The blood vessels of the dura and brain usually maintain separate blood supplies. Only with a relatively rare disorder called dural arteriovenous fistula, or DAVF, do they become mingled.
“It’s an anatomical connection that shouldn’t be there,” says neurosurgeon Judy Huang.
DAVFs occur when an artery from the dura forms a connection with a vein from the brain. Sometimes, Huang says, they cause no symptoms at all—it’s something doctors only find incidentally when the brain is imaged for another purpose. In these cases, Huang and her colleagues might recommend observation and periodic monitoring. In other cases, the symptoms are bothersome, but not dangerous. Depending on the fistula’s location, patients might complain of vision problems, tinnitus or nonspecific headaches.
In a few instances, however, angiograms show the dangerous feature known as cortical venous reflux, in which blood flow backs up into the brain. Because DAVFs with this characteristic have a high risk of brain hemorrhage, Huang says, those must be treated.
Huang and other specialists at Johns Hopkins use a variety of techniques to remove DAVFs, tailored to a patient’s anatomy and specific needs. Most DAVFs can be resolved with endovascular techniques, she says, in which the affected area is accessed by feeding a catheter into the femoral artery, which follows blood vessels to the brain. When the catheter reaches its destination, an embolic material is inserted—coils or a type of glue or viscous particles that solidify—to close off the fistula. This approach might not always be complete on the first try, she says. Repeat procedures are usually necessary to definitively eradicate the fistula.
If an endovascular approach isn’t possible, Huang explains, patients might need open surgery. After approaching the DAVF directly, she and her neurosurgical colleagues treat it by clipping or cauterizing it. A third option, when the malformation isn’t accessible through other routes, is radiosurgery. By hitting the fistula with high-dose radiation, Huang says, doctors can treat it with minimally invasive techniques.
Patients usually receive only one of these options, but occasionally a combination approach is best, she says.
Johns Hopkins’ Cerebrovascular Center can provide all these options, she adds, thanks to a cross-disciplinary team of neurosurgeons, interventional neuroradiologists, neurologists and other specialists who work together to develop a comprehensive treatment plan for each patient.
“There’s so much variability in these lesions,” Huang says. “They really range from a very mild pathology to severe, so you need the availability of dedicated specialists who can offer treatment that is carefully tailored for the individual patient.”
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