A novel "Y" stent flow diversion technique for the endovascular treatment of bifurcation aneurysms without endosaccular coiling

Abstract

Background and purpose: Stent-assisted endovascular treatment and flow diversion techniques are increasingly used for the management of wide-neck intracranial aneurysms. We report our initial clinical experience using a new flow diversion technique for the endovascular management of bifurcation aneurysms.

Materials and methods: Eight bifurcation aneurysms were treated by placing 2 stents in Y-configuration with no accompanying endosaccular packing. This treatment technique aimed at flow diversion was selected in these cases because 1) the aneurysm was giant and causing mass effect, 2) the emanating branches were incorporated within the sac, or 3) the aneurysm was too small. Aneurysms were located at middle cerebral (5 aneurysms) and basilar artery bifurcations (3 aneurysms). Five aneurysms were small, 1 was large, and 2 were partially thrombosed giant. Closed-cell stents were used in all Y-stent placement procedures.

Results: In all aneurysms, both stents could be placed at the intended locations without any procedural complication. Follow-up angiograms obtained at 3 months to 2 years demonstrated that all stents were patent except for one with asymptomatic P1 occlusion. Complete occlusion with remodelled bifurcation was observed in all middle cerebral artery bifurcation aneurysms and the large basilar tip aneurysm. Residual filling despite reduction in size was observed in both of the partially thrombosed giant aneurysms at 2-year and 3-month follow-up angiograms, respectively.

Conclusions: Flow diversion with double stent placement in Y-configuration provided successful and stable aneurysm occlusion. The technical and clinical results achieved are highly encouraging that this technique may contribute to the endovascular treatment of these complex bifurcation aneurysms.

Fig 1.

Initial 3D reconstruction image of rotational angiogram (A) shows small wide-neck MCA trifurcation aneurysm. Posttreatment 3D reconstruction image of flat panel CTA (B) demonstrates the Y-configuration of the 2 stents placed within the MCA branches crossing the neck of the aneurysm, which is still filling in between. 3D reconstruction image of the flat panel CTA (C) obtained at 1-month control and 3D image of rotational angiogram at 1-year control (D) showing complete occlusion of the aneurysm and reconstruction of the trifurcation.

Fig 2.

Pretreatment left vertebral artery angiogram in oblique projection (A) and 3D reconstruction image of rotational angiogram (B) show the basilar tip aneurysm without a definable neck. Posttreatment angiogram (C), nonsubtracted view, shows the “Y”-configured stents extending into the both posterior cerebral arteries from the basilar trunk. The 2-year follow-up angiogram (D) and 3D reconstruction image of rotational angiogram (E) demonstrate completely remodeled basilar bifurcation with the aneurysm sac disappeared and occlusion of the right P1.

Fig 3.

T2-weighted axial MR image (A) shows the giant basilar tip aneurysm causing mass effect and increased signal intensity in the brain stem. Pretreatment right vertebral artery angiogram in Towne projection (B) demonstrates the large and wide-neck basilar tip aneurysm. Posttreatment coronal (C) and axial (D) 3D reconstruction images of flat panel CTA demonstrate the “Y”-configuration of double stent placement. The 1-month follow-up axial CTA image (E) shows the significant decrease in size of the patent aneurysm lumen. The 2-year control angiogram (F), nonsubtracted view, shows progressive thrombosis and change in the shape of the aneurysm sac so that it became a bilobulated, small aneurysm. The larger lobule was coiled in the same session, and the small lobule is still being followed. G, Angiogram, subtracted image obtained after coiling.