Bypass Surgery for the Treatment of Dolichoectatic Basilar Trunk Aneurysms

Abstract

BACKGROUND The treatment of dolichoectatic basilar trunk aneurysms has been ineffectual or morbid due to non-saccular morphology, deep location, and involvement of brainstem perforators. Treatment with bypass surgery has been advocated to eliminate malignant hemodynamics and stabilize aneurysm growth. OBJECTIVE To validate that flow alteration with bypass and parent artery occlusion favorably impacts aneurysm progression. METHODS Surgical management evolved in 3 phases, each with different hemodynamic alterations. RESULTS During a 17-year period, 37 patients with dolichoectatic basilar trunk aneurysms were retrospectively identified, of whom 21 patients were observed, 12 treated immediately, and 4 selected for treatment after clinical progression. In Phase 1, flow reversal was overly thrombogenic, despite heparin (N=5, final mortality, 100%). In Phase 2, flow reduction with IC-IC bypass was safer than flow reversal but did not prevent progressive aneurysm enlargement (N=3, final mortality 67%). In Phase 3, distal clip occlusion of the basilar trunk aneurysm preserved anterograde flow in the aneurysm without rupture, but reduced flow threatened perforator patency, despite treatment with Clopidogrel (Plavix) (N=8, final mortality 62%). CONCLUSION Shifting treatment strategy for dolichoectatic basilar trunk aneurysms improved surgical (80% to 50%) and final mortalities (100% to 62%), with stabilization of aneurysms in the Phase 3 survivors. Good outcomes are determined by perforator preservation and mitigating aneurysm thrombosis. Occlusion techniques with increased distal run-off appear to benefit perforators. The treatment of dolichoectatic basilar trunk aneurysms can advance through concentrated management in dedicated centers, concerted efforts to study morphology/hemodynamics with computational methods, and widespread collection of registry data.

Revascularization of the upper posterior circulation with the anterior temporal artery: an anatomical feasibility study

“…2,10,11,27 Of those lesions amenable to surgery, certain unclippable aneurysms may require bypass after aneurysm trapping, based on the pre-and/or intraoperative studies. 15,17,20,21,[26][27][28] Similarly, the surgical results with dolichoectatic aneurysms affecting the basilar trunk favor the use of MCA-PCA bypass. 21 We have shown that the frontotemporal-orbitozygomatic approach provides excellent exposure of the proximal PCA and the SCA through the pretemporal corridor while minimizing temporal lobe retraction.…”

“…bral artery (MCA) to the SCA with an interposition graft, in combination with distal clip occlusion of the aneurysm, showed promising results. 21 These bypass choices that rely on scalp arteries or interposition grafts may not always be feasible. The STA or radial artery grafts (RAGs) may not be always available, 24 and the saphenous vein graft may be too large in caliber to match the PCA or SCA.…”

Endovascular management of fusiform aneurysms in the posterior circulation: the era of flow diversion

“…19 The study included 37 patients, and the bypass evolved in 3 distinct phases, each with different hemodynamic alternations. Surgical bypasses consisted of EC-IC (STA-SCA and STA-PCA) bypasses in Phase 1 for flow reversal, IC-IC (VA-SCA) bypasses in Phase 2 for flow reduction, and Phase 3 (middle cerebral artery-PCA) for distal occlusion.…”

Predictive modeling and in vivo assessment of cerebral blood flow in the management of complex cerebral aneurysms

“…Necessity is an important driver of innovation, and we have used predictive modeling primarily in some of the most challenging aneurysms we have encountered in clinical practice, as in cases of dolichoectatic basilar artery trunk aneurysms. 20 …”