RT Journal Article SR Electronic T1 E-012 Direct transcrainal puncture of a hemangiopericytoma and successful embolization with Onyx JF Journal of NeuroInterventional Surgery JO J NeuroIntervent Surg FD BMJ Publishing Group Ltd. SP A35 OP A35 DO 10.1136/neurintsurg-2011-010097.78 VO 3 IS Suppl 1 A1 D Kreitel A1 P Conant A1 K Liu A1 M Jensen A1 A Evans YR 2011 UL http://jnis.bmj.com/content/3/Suppl_1/A35.1.abstract AB Introduction Hemangiopericytomas (HPC) comprise 1% of intracranial neoplasms and are traditionally treated with preoperative embolization and resection. This is a case of direct transcranial puncture and Onyx embolization of a right extra-axial tentorial HPC.Materials and Methods A 61-year-old woman presented to the University of Virginia Medical Center following an aborted resection at an outside hospital of what was believed a meningioma. During the operation significant bleeding occurred. Frozen section identified it as a HPC. Angiography was performed for preoperative embolization of the lesion. The tumor was highly vascular and had arterial feeders from the right ECA and parasitized vessels from the right MCA, PCA, and SCA. The only appropriate branch for embolization was a small tortuous branch of the middle meningeal artery. Attempts to select this vessel using 0.014 and 0.010 microguidewires were unsuccessful. The vessel proved to be too small to catheterize. The team opted to attempt to treat the tumor by a direct stick embolization through the gap in the craniotomy defect. The scalp was surgically prepped and a diagnostic angiographic catheter was placed into the right ECA trunk to perform control angiograms and to monitor embolization. This was used to puncture the center of the supratentorial component. Embolization was performed with Onyx 34 (eV3, Irvine, California, USA) with continuous fluoroscopic monitoring using a negative roadmap technique. The needle was repositioned five times and a total of five cc's of Onyx was injected into the supratentorial component. The infratentorial component was not treated because it was small and less accessible. Surgical resection was performed the following day. The supratentorial section was completely necrotic and avascular. The infratentorial tumor was very vascular but resected with acceptable blood loss.Discussion Transarterial embolization of vascular tumors of the head and neck is a standard procedure; direct stick embolization is rare. Direct puncture embolization with NBCA of vascular tumors has been reported. Onyx has been used for direct stick embolization of carotid body tumors. In this case, the crainotomy defect allowed for direct access to a tumor which could not have been embolized with transarterial techniques. In principle, otherwise inaccessible intracranial tumors would be embolized via small burr holes.Conclusion Successful Onyx embolization of intracranial vascular tumors can be achieved via unique accesses.Abstract E-012 Figure 1