Transarterial coil and ONYX embolization for delayed rupture of a large cavernous internal carotid aneurysm after flow diverter treatment: A case report

Objectives: We present an innovative method of transarterial trans-cell coil and ONYX (Medtronic, Minneapolis, MN, USA) for bailout of delayed rupture, resulting in a direct cavernous carotid fistula (d-CCF) after flow diverter (FD) treatment for a large cavernous internal carotid artery aneurysm. Case presentations: A 72-year-old male patient who underwent FD implantation with the Pipeline Flex (Medtronic) for an aneurysm of this location measuring 15 mm in diameter. He developed a sudden-onset headache and pulsatile tinnitus on postoperative day 7 due to delayed rupture of the aneurysm, resulting in a high-flow d-CCF. The transarterial trans-cell approach was achieved by selecting a combination of several types of microcatheters and micro-guidewires, along with the development of an access system. Despite the use of extensive coil embolization for the aneurysm, the d-CCF persisted. To address this, liquid embolization utilizing ONYX was conducted, resulting in complete occlusion of the d-CCF. Furthermore, during a follow-up examination three months later, complete occlusion of the aneurysm was observed due to the effect of the FD. Conclusions: Transvenous embolization (TVE) or parent artery occlusion (PAO) has been reported as the rescue treatment of choice for delayed rupture of such an aneurysm following FD implantation; however, TVE may not always result in complete cure with a single treatment, while PAO carries the risk of potential ischemic complications. An alternative option, transarterial trans-cell embolization using a combination of coil and ONYX, has proven to be effective, although it has some limitations.