1 Multiple Paraclinoid Aneurysms of the Internal Carotid Artery

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Multiple Paraclinoid Aneurysms of the Internal Carotid Artery

SHIGEAKI KOBAYASHI, YUKINARI KAKIZAWA, KEIICHI SAKAI, AND YUICHIRO TANAKA

Diagnosis Three paraclinoid aneurysms

Problems and Tactics Three unruptured aneurysms were incidentally found at a short segment of the C2–3 of the internal carotid artery (ICA) in a healthy young man. Despite the difficulties in clipping all three aneurysms, surgical treatment was chosen because of no guarantee of future subarachnoid hemorrhage (SAH).

Keywords Paraclinoid aneurysm, carotid cave aneurysm, multiple clippings, ring clips

Clinical Presentation

This 29-year-old man had complained of right nocturnal retroorbital pain. He had suffered a skull base injury at the age of 10. Carotid angiograms showed multiple paraclinoid aneurysms in the ICA: a small clinoid segment aneurysm (3 mm), a carotid cave aneurysm (6 mm), and a carotid ophthalmic aneurysm (9 mm) in the order from proximal to distal location (Fig. 1–1).

Surgical Technique

The patient was placed in the supine position. The right cervical carotid artery was exposed for possible temporary occlusion as well as for intraoperative angiography. A right frontotemporal craniotomy was performed. After durotomy, the sylvian fissure was opened. The carotid ophthalmic aneurysm was not seen initially. The anterior clinoid process was drilled intradurally, and the optic canal was unroofed. After removal of the clinoid process, it became possible to see the distal neck of the carotid ophthalmic aneurysm. The optic sheath was opened superiorly. The proximal dural ring was opened to expose the genu and the axilla of the ICA. The bleeding from the cavernous sinus was somewhat profuse, but it was controllable by packing with pieces of Oxycel®. There was considerable adhesion between the clinoid segment of the ICA and periosteum, which is usually rather free. Careful dissection of the distal dural ring was performed first laterally from the axilla portion, but it was extremely difficult to dissect it medially because the carotid ophthalmic aneurysm was located nearby making it difficult to mobilize the artery and prepare the carotid cave aneurysm for clipping. The distal dural ring was dissected as much as possible around the carotid artery, except just under the carotid ophthalmic aneurysm. In dissecting the clinoid segment of the ICA, which is C3–4, we could see a small aneurysmal dilation at the ventromedial side of the segment. Finally, dissection was performed to mobilize the initial segment of the ophthalmic artery from the dura to create a space for clipping the carotid cave and carotid ophthalmic aneurysms.

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