Abstract
We retrospectively analyze of our experience with unruptured thrombosed large (TL) vertebral artery (VA) aneurysms and strategies for their treatment. From January 2006 to November 2011, 11 patients with a TLVA aneurysm of more than 15 mm in diameter were treated by open surgery. Various techniques are required to revascularize a posterior cerebellar artery (PICA) or a VA itself, preserve of perforating arteries arising from an aneurysm and resect an aneurysm with a mass effect. In the case of patients without a contralateral VA, when an occlusion of the parent artery is needed, a high flow bypass such as a V3-radial artery (RA)-P2 bypass should be considered. In case of PICA involved aneurysms, an occipital artery (OA)-PICA bypass is required. Basically, trapping of the TL aneurysm is recommended to prevent regrowth. However, contrived proximal clipping is thought to be suitable for some asymptomatic TL aneurysms, which themselves exhibit perforating arteries. As for symptomatic TL calcified aneurysms manifesting a mass effect, the aneurysm should be resected because we cannot necessarily expect shrinkage even after aneurysmal thrombosis. When resecting a TL calcified aneurysm, it is desirable to leave a part of the aneurysmal outer shell adhered to surrounding structures. One patient was treated with an OA-V4 bypass and aneurysm resection. The V4 bypass supplied anterograde blood flow for the basilar artery, substituting for a V3-RA-P2 bypass. The results of the 11 patients on the modified Rankin Scale assessed at present were 0 in 4, 1 in 4, 2 in 1, and 3 in 2, respectively. Poor outcome is related to perforating injuries. Regrowth or bleeding from the aneurysm has not been observed.
It is important to perform an uncompromising therapy for the patient of a TLVA aneurysm, so several techniques must be mastered.
