PHIL® Embolic System Pediatric IDE

Inclusion Criteria: * Subject is \<22 years of age * Subject and legally authorized representative are willing and capable of complying with all study protocol requirements, including specified follow-up period. * Subject's legally authorized representative(s) must sign and date an IRB approved written informed consent prior to initiation of any study procedure * Subject has an intracranial dAVF that is deemed appropriate for embolization with PHIL without significantly increased risk to collateral or adjacent territories, OR subject has been previously treated with other embolic materials for dAVF. Exclusion Criteria: * Subject presents with an intracranial mass or is currently undergoing radiation therapy for carcinoma or sarcoma of the head or neck region * Subject has known allergies to DMSO (dimethyl sulfoxide), iodine or heparin. * Subject with a history of life threatening allergy to contrast media (unless treatment for allergy is tolerated). * Female subject is currently pregnant. * Subject has an acute or chronic life-threatening illness other than the neurological disease to be treated in this study including but not limited to any malignancy or debilitating autoimmune disease * Subject has existing severe or advanced comorbid conditions which significantly increase general anesthesia and/ or surgical risk * Evidence of active infection at the time of treatment. * Subject has a history of bleeding diathesis or coagulopathy, international normalized ratio (INR) greater than 1.5, or will refuse blood transfusions. * Subject weighs ≤ 2.5kg Angiographic * Subject has severe calcification or vascular tortuosity that may preclude the safe introduction of the sheath, guiding catheter, or access to the lesion with the microcatheter. * Contra-indication to DSA, CT scan or MRI/ MRA * History of intracranial vasospasm not responsive to medical therapy * Extra-cranial stenosis or parent vessel stenosis \> 50% proximal to the target lesion to be treated. * Subject has a propensity to contrast induced renal injury or a potential to nephrogenic systemic fibrosis