Endovascular embolization of complex hypervascular skull base tumors Aaron A. Cho, MD, Michael Annen, MD  Operative Techniques in Otolaryngology-Head and Neck Surgery  Volume 25, Issue 1, Pages 133-142 (March 2014) DOI: 10.1016/j.otot.2013.11.016 Copyright © 2014 Terms and Conditions

Figure 1 Right glomus jugulare. (A) Contrast-enhanced CT demonstrates robust enhancement of the large tumor expanding the jugular foramen and destroying the adjacent bone. (B) Superselective angiogram after positioning a 2.4-F microcatheter (arrow) in the neuromeningeal trunk of the ascending pharyngeal artery demonstrates intense tumor blush. Glomus jugulare tumors receive primary arterial supply from the neuromeningeal trunk of the ascending pharyngeal artery. Operative Techniques in Otolaryngology-Head and Neck Surgery 2014 25, 133-142DOI: (10.1016/j.otot.2013.11.016) Copyright © 2014 Terms and Conditions

Figure 2 (A) Lateral view of the external carotid artery angiogram using a 4-F catheter with the tip positioned in the external carotid artery (black asterisk). (B) Superselective angiogram of the occipital artery with the 2.4-F microcatheter tip positioned in the occipital artery (black arrow). On the external carotid artery angiogram (A) the glomus jugulare demonstrates robust contrast blush with dominant supply from the ascending pharyngeal artery; however, contribution of individual branch arteries to tumor vascularity is difficult to distinguish. Selective angiography of the occipital artery (B) allows for identification of the stylomastoid branch (white arrow). The stylomastoid branch of the occipital artery contributes a small vascular blush along the posterior inferior margin of the tumor. Operative Techniques in Otolaryngology-Head and Neck Surgery 2014 25, 133-142DOI: (10.1016/j.otot.2013.11.016) Copyright © 2014 Terms and Conditions

Figure 3 MRI at the level of the cerebellopontine angle (CPA). (A) T1, (B) T2, (C), and (D) T1 postcontrast images demonstrate a large meningioma (asterisk) in the right CPA, which demonstrates marked enhancement. On the postcontrast images (C and D), note the proximity of the mass to the right sigmoid sinus (arrow). Inadvertent injury to the sinus during resection may result in alteration of venous drainage to normal brain parenchyma. Operative Techniques in Otolaryngology-Head and Neck Surgery 2014 25, 133-142DOI: (10.1016/j.otot.2013.11.016) Copyright © 2014 Terms and Conditions

Figure 4 MRI at the level of the jugular foramen. (A) coronal FLAIR, (B) axial T2 weighted, (C) axial T1 weighted, and (D) axial T1 weighted post gadolinium contrast images demonstrate a heterogeneous signal intensity schwannoma with intense contrast enhancement (white arrow) expanding the left jugular foramen and completely compressing the left jugular vein. Note the flow void from the left internal carotid artery (ICA) abutting the anterior margin of the tumor (black arrows). Cerebral angiography and ICA balloon test occlusion can dynamically evaluate the cerebral vascular flow in the event of tumor involvement of the ICA requiring artery sacrifice or inadvertent injury to the ICA during surgery. FLAIR, fluid attenuated inversion recovery. Operative Techniques in Otolaryngology-Head and Neck Surgery 2014 25, 133-142DOI: (10.1016/j.otot.2013.11.016) Copyright © 2014 Terms and Conditions

Figure 5 Preoperative endovascular embolization of a large glomus jugulare tumor. (A) Pre-embolization lateral external carotid angiogram demonstrates intense tumor blush (white asterisk). (B) Postembolization lateral external carotid angiogram demonstrates devascularization of the tumor by the Onyx cast (black asterisk). (C) Postembolization unsubtracted lateral rotational fluoroscopic image demonstrates the Onxy cast and its relation to the osseous structures of the skull base. (D) 3D reconstruction from a dual-volume rotational angiogram allows for 3D visualization and image manipulation to evaluate the Onyx cast (black asterisk) within the tumor and its relation to the skull base. 3D, 3-dimensional. (Color version of figure is available online.) Operative Techniques in Otolaryngology-Head and Neck Surgery 2014 25, 133-142DOI: (10.1016/j.otot.2013.11.016) Copyright © 2014 Terms and Conditions

Figure 6 Particulate embolic agents. (A) Nonabsorbable polyvinyl alcohol particles are used for tumor embolization. Particle size varies from 45-2,000µ in diameter. PVA 100 particles have diameter sizes of 90-180µ and are used for deeper penetration into the tumor capillary bed for more robust tumor devascularization. Larger diameter PVA particles (300-500µ and 500-710µ) are used for tumor embolization and feeding vessel occlusion with little risk for cranial nerve injury (by devascularization of the vasa nervorum) or particles transiting the tumor vascular bed into dangerous communicating vessels. (B) Absorbable gelfoam sheet can be cut and rolled into gelfoam torpedoes or macerated and mixed into a gelfoam slurry for transient tumor embolization or hemostasis. Operative Techniques in Otolaryngology-Head and Neck Surgery 2014 25, 133-142DOI: (10.1016/j.otot.2013.11.016) Copyright © 2014 Terms and Conditions

Figure 7 Liquid embolic agents. (A) n-Butyl cyanoacrylate (n-BCA), ethiodized oil, and tantalum powder (Trufill; Codman Neurovascular, Inc) are mixed to form a liquid embolic agent. The n-BCA is a clear, free-flowing liquid that polymerizes upon body fluid or tissue contact via an anionic mechanism. Ethiodized oil is a straw-to-amber colored, oily fluid containing iodinated poppy seed oil and is used as a radiopaque polymerizing retardant. The amount of ethiodized oil used will vary the rate of polymerization. Tantalum powder is a finely ground, irregularly shaped, dark gray metal that can be used with ethiodized oil to make the n-BCA radiopaque. (B) Onyx (eV3 Endovascular Inc) is a nonadhesive liquid embolic agent comprising EVOH (ethylene vinyl alcohol) copolymer dissolved in DMSO (dimethyl sulfoxide) and suspended micronized tantalum powder to provide contrast for visualization under fluoroscopy. Onyx 18 (6% EVOH) travels distally and penetrates deeper into the nidus owing to its lower viscosity compared with Onyx 34 (8% EVOH). Final solidification of Onyx cast occurs within 5 minutes. Operative Techniques in Otolaryngology-Head and Neck Surgery 2014 25, 133-142DOI: (10.1016/j.otot.2013.11.016) Copyright © 2014 Terms and Conditions

Figure 8 Selective angiography and endovascular coil occlusion. (A) Selective angiography (frontal view) demonstrates common origin of the ascending pharyngeal artery (black arrow) and occipital artery (white arrow). Hypervascular glomus jugulare tumor blush (asterisk) supplied primarily by the neuromeningeal trunk of the ascending pharyngeal artery. Tumor also receives some vascular supply along its posterior lateral margin from the stylomastoid branch (dashed arrow) of the occipital artery. (B) The occipital artery has been occluded with an endovascular platinum embolization coil (open arrow) just distal to the origin of the stylomastoid branch (dashed arrow) to prevent inadvertent migration of embolic agents from the occipital artery (white arrow) to the vertebral artery via muscular branch anastomoses. Operative Techniques in Otolaryngology-Head and Neck Surgery 2014 25, 133-142DOI: (10.1016/j.otot.2013.11.016) Copyright © 2014 Terms and Conditions