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Arteriovenous Malformation (AVM) CASE Studycase Presentation: A 40-year-old male patient presented with new onset of grand mal seizures over a two-month period. the initial brain mri from an outside hospital demonstrated enlarged vessels involving the right temporal lobe consistent with an AVm.
AVM EMBolIzAtIoN ProCEdurE
Embolization is done through a microcatheter advanced into feeding arteries.
From there, embolic material is injected into the nidus over a certain period
of time under fluoroscopic guidance. Onyx® is an FDA-approved alcohol-
based liquid and cohesive embolic material now routinely used to embolize
cerebral vascular lesions. Each Onyx injection takes 30 to 60 minutes.
General y, two to three feeding arteries are used for each embolization,
depending on the microcirculation and anatomical structure of the AVM.
Each procedure takes approximately two to three hours and is done under general anesthesia. The patient typical y spends one to two days in the intensive care unit for neurological examination and close observation of Figure 1: Diagnostic imaging found a
Spetzler-martin grade i i AVm with a diameter of 3 cm x 4 cm, feeding from branches of the right middle cerebral artery, the anterior choroidal artery and the posterior cerebral artery. the venous drainage involved the superficial and deep venous drainage system. in addition, several direct arteriovenous shunts were noted. no arterial or venous aneurysms Figure 2: fol owing two embolization
procedures, imaging shows the residual AVm and the “onyx cast” or embolic material that was injected. the onyx embolizations closed of more than 90 percent of the nidus without compromising the venous outflow of normal Figure 3: the postoperative ct scan
residual embolic material and postoperative changes are seen. the transcranial Doppler flow studies demonstrated normal antegrade flow in the right middle cerebral artery.
FolloWInG ReFeRRal to santa Barbara neuroscience of the injected onyx material. The second option would Institute, the patient was started on keppra (levetiracetam) involve radiosurgery—utilizing either Gamma knife®, a to prevent additional seizures, and a diagnostic cerebral linear accelerator, or cyberknife®—to deliver high-dose focal angiography was performed. (The results of the brain MRI radiation to the residual nidus while shielding the rest of the and the cerebral angiogram are illustrated in Figure 1.) The
patient then underwent two onyx® embolization procedures In this case, surgical resection was the better choice for scheduled approximately one week apart. To reduce the several reasons: the patient was young and otherwise healthy; perioperative risks for hemorrhage, only 30 to 45 percent of the aVM surgical risks were low after more than 90 percent the nidus (center) of the aVM was embolized in each session.
of the nidus was occluded with embolic material; and the This patient received a total of three injections through location of the aVM (right side and temporal lobe) was branches and feeding arteries of the right middle cerebral artery and one injection via the basilar artery and the posterior a right-sided craniotomy and resection of the aVM was cerebral artery. Figure 2 demonstrates a microcatheter
performed using standard neurosurgical and microsurgical injection and portions of the nidus prior to embolization. The techniques. Intraoperative advantage was taken using final angiogram shows less than 10 percent of residual nidus. BrainlaB frameless navigation to localize the residual nidus This portion of the aVM was not embolized, as it would and the draining veins. The procedure was uneventful. have been at significant risk to the patient. This particular standard aVM protocols included a postoperative angiogram area is fed from the anterior choroidal artery. This artery to be certain the entire aVM was removed and confirm carries blood not only to the aVM but also to very important no angiographic signs of early venous drainage. Figure 3
normal brain structures, such as the internal capsule and the demonstrates the postoperative angiogram without any basal ganglia. Treating this portion of the aVM with surgical resection or radiosurgery would be significantly safer. The patient recovered very well from the surgery and was discharged on postoperative day five without neurological deficits. he returned to work approximately four weeks aVM eradICatIon optIons
after the second embolization, a discussion with the patient after surgery.
and his family took place on two options for completely To access an in-depth video presentation of this case by eliminating the aVM. The first option would be a craniotomy Dr. Zauner with 3-D rotational angiograms and other cases, and and surgical resection of the residual nidus, including most additional images, visit our website at www.sbni.org.

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