Personalized selection of proximaledge position of stent in endovascular ophthalmic aneurysms treatment

Background. Aneurysms of the ophthalmic segment of the internal carotid artery are quite rare and account for no more than 5 % of all intracranial aneurysms. Stent-assistance using Laser-cut stents is an important option and before the advent of braided stents was the mainstay in the endovascular treatment of complex aneurysms. The study is aimed at analyzing the peculiarities of assisting stent implantation into the internal carotid artery taking into account the anatomical characteristics of its siphon (the place of typical collapse and under-opening of the stent at acute anterior knee angle), influencing the increase of radicality of aneurysm disconnection from the blood flow, as well as evaluating the safety and efficacy of Laser-cut stent-assistence technique in the treatment of aneurysms of the ophthalmic segment of the internal carotid artery. Design and methods a retrospective analysis of patients from the database from 2013 to 2016 was performed. All patients with ophthalmic segment aneurysms who underwent aneurysm occlusion using any laser-cut self-expanding nitinol assisted stent were included. Stent implantation technique and positioning points, intraoperative and postoperative complications, primary and distant angiographic results (Raymond-Roy Occlusion Classification, RROC) were analyzed. Results. 57 patients with 57 aneurysms of the ophthalmic segment of the internal carotid artery operated using laser-cut stent-assist technique were included in the study (Enterprise I: 53 aneurysms; Neuroform: 4 aneurysms). Primary total (RROC I) — 37 (64.9 %), subtotal (RROC II) — 14 (24.6 %) and partial (RROC III) — 6 (10.5 %) were switched off from blood flow. Radical aneurysm disconnection from the blood flow was achieved in all cases using a modified stent implantation technique (proximal-edge position n = 24) — when using a short 14 mm Enterprise stent (n = 8), as well as when positioning the Enterprise stent from the middle cerebral artery into the internal carotid artery up to the natural bend of the artery in the anterior knee of the siphon (the proximal end of the stent corresponds to the aneurysm neck regardless of the length of the stent itself) (n = 16). Similar results in terms of radicalization were achieved with the Neuroform stent (n = 4). At standard implantation (middle third of the stent corresponds to the aneurysm neck) of the Enterprise stent (n = 29), only in 9 observations radical disconnection of the aneurysm from the blood flow was achieved. On control angiography at the term not earlier than 6 months aneurysms were radically excluded (RROC I) in 43 (75.4 %) patients, subtotally (RROC II) in 5 (8.8 %) and partially (RROC III) in 9 (15.8 %) patients. Conclusions. Endovascular surgical interventions using stent-assistance in the treatment of patients with aneurysms of the ophthalmic segment of the internal carotid artery are effective, but due to the stent design, the shape of the internal carotid artery siphon plays a key role in achieving a radical treatment result. Personalized assessment of anatomical and morphometric features of the aneurysm and the aneurysm-bearing artery, in particular, the analysis of the curvature of the natural curvature of the siphon, when choosing the type and length of the assisting stent are the key points for achieving the optimal result of the operation and reducing the risks of complications. The proposed method of implantation using proximal-edge position allows to achieve a radical result of aneurysm occlusion regardless of the stent length and minimize the risks of stent collapse and ischemic complications. A personalized approach to the choice of short assisting stents is a consequence of the proximal-edge position technique, as it is notnecessary to lead the excessive stent length into the middle cerebral artery.

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