Abstract
Internal carotid artery (ICA) aneurysms arising from around the carotid dural ring are of considerable surgical interest due to their anatomical features and technical difficulties. With the recent refinement of microsurgical techniques, their management has changed from conservative surgery to direct neck clipping. Different authors call the ICA aneurysms arising near the dural ring by different names such as“ventral internal carotid aneurysms”,“paraclinoid aneurysms”or“infraclinoidal aneurysms.”Some of these aneurysms were considered unclippable or associated with disastrous results when surgically approached.
We report a subgroup of ICA aneurysms located around the carotid dural ring which we call Juxta-DURAL RING aneurysms. These aneurysms are classified into three types: intradural type (intradural aneurysm), carotid cave type (carotid cave aneurysm) and infraclinoid type (infraclinoid aneurysm). The intradural aneurysm arises from the ICA distal to the origin of the ophthalmic artery and correspond to so-called IC-ophthalmic aneurysms which are juxtaposed on the dural ring. The carotid cave aneurysm is located in a small dural recess (carotid cave) proximal to the origin of the ophthalmic artery and at the angiographical genu. The infraclinoid aneurysm may be included in the conventional intracavernous sinus aneurysms, and is located extradurally in the infraclinoid space close to the dural ring. From the point of view of surgical anatomy, clipping of these aneurysms requires essentially the same surgical techniques; complete removal of the anterior clinoid process, unroofing of the optic canal, complete opening of the dural ring, and exposure of the surgical genu and axilla of the ICA via the pterional approach. Utilizing these techniques they are clippable with relative ease. In this paper, our surgical technique is discussed giving explanations of surgical anatomy and clinical cases.
