Diagnosis and Endovascular Treatment of Vertebral Arteriovenous Fistulas in Neurofibromatosis Type 1

We present diagnostic problems, strategies, techniques and material selection for endovascular treatment of high flow arteriovenous fistula (AVF) of tortuous and fragile vertebral artery (VA) with neurofibromatosis type 1 (NF1). Diagnosis of NF1 was easy in four of our cases because of neurofibromatosis, skin pigmentation and various skeletal abnormalities. These stigmas of NF1 were lacking in one case, and the only clue to the diagnosis was ovoid bone defects of the skull vault. Diagnosis was made by performing biopsy of scalp neurofibromas incidentally found on CT. In two initial cases, venous varix were packed with coils by transvenous approach after the transarterial embolisation failed to completely cure the fistula. In three recent cases, blood flow through the fistula was markedly reduced as an initial step by placing detachable coils into the distal and proximal stumps of the afferent VA. Then a liquid adhesive was injected under systemic hypotension to completely occlude the fistula. Control angiography revealed that the AVFs were completely occluded in all cases. Longterm angiographical and clinical status have been stable in all cases. Trying to attain complete occlusion of fistulas using detachable balloons is not an appropriate treatment option for high flow fistulas situated on markedly dilated, tortuous and fragile VAs of patients with NF1. Also, trapping of fistulas is not justified because of the numerous potential feeding pedicles, and makes the following procedure difficult.