Neurosurgery Department, University General Hospital of Alicante, Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO), Alicante, Spain
The three subtypes are the superiorly pointing aneurysms originating at the ophthalmic artery (i.e., ophthalmic artery [OA] aneurysms), the medially pointing aneurysms originating from the superior hypophyseal trunk, and aneurysms originating from a perforator-free part of the ICA, the so-called atypical or blister ICA aneurysms 4).
Most commonly, ophthalmic artery aneurysms present with progressive visual disturbance or exophthalmos, although they may be asymptomatic.
Clinical presentations included subarachnoid hemorrhage in 23 cases (29%) and visual deficits in 24 (30%); five patients exhibited both hemorrhage and visual loss. Twenty-eight aneurysms were incidentally identified. Ophthalmic artery aneurysms arose from the internal carotid artery (ICA) just distal to the ophthalmic artery, pointed superiorly or superomedially, and (when large) deflected the carotid artery posteriorly and inferiorly, closing the siphon. Abnormalities relating to vision were not identified until the aneurysm realized giant proportions. The optic nerve was typically displaced superomedially, which restricted contralateral extension until late in the clinical course; unilateral nasal field loss was seen in 12 patients. 5).
Unruptured large OA aneurysms frequently present with gradual loss of vision. The goal of their treatment is then twofold: to exclude the aneurysm from the circulation and to preserve or restore visual function. Treatment of OA aneurysms can be surgical or endovascular, depending on the mode of presentation, aneurysm geometrics and size, as well as the patient́ s medical condition 6).
When direct operation is performed for a carotid-ophthalmic artery aneurysm, care must be taken to avoid optic nerve injury caused by the retraction and/or the heat of the drill 13).
Disadvantages of a contralateral approach (CA) are deep and narrow surgical corridors and inconsistent ability to achieve proximal control of the supraclinoid internal carotid artery (ICA). However, a CA remains as microsurgical option for selected internal carotid artery-ophthalmic segment (ICA-opht) aneurysms.
Its feasibility depends on specific anatomic parameters related to the aneurysm itself and to the prechiasmatic distance, interoptic distance, and relationship of the ICA with the anterior clinoid process 14).
In selected patients, transient cardiac arrest induced by adenosine during a contralateral approach allows a brief flow arrest and softening of the aneurysm for a safer exposure and clipping 15).
Ophthalmic artery aneurysms may be adequately and safely treated with either the Pipeline Embolization Device (PED) or coil embolization. However, treatment with the PED carries a higher risk of impeding flow to the ophthalmic artery, although this did not result in clinical sequelae in a study 16).
Peschillo S, Biraschi F, Diana F, Colonnese C, Marenco M, Delfini R. Aneurysms of the Intracranial Segment of the Ophthalmic Artery Trunk: Case Report and Systematic Literature Review. J Neurol Surg A Cent Eur Neurosurg. 2017 Jul 25. doi: 10.1055/s-0037-1604268. [Epub ahead of print] PubMed PMID: 28743134 17).