1162. Novel Revascularization Technique for P2-P3 Complex Aneurysms. Surgical and Anatomical Simulation.

Authors: Sergio Garcia; José González Sánchez, MD, PhD; Ming Liu, MD; Michael Lawton, MD; Arnau Benet, MD (Barcelona, Spain)

Introduction: Management of distal posterior cerebral artery(PCA) aneurysm is source of great controversy. Parent vessel occlusion (PVO) may be effective but endangers flow to the visual cortex and the preservation of mesencephalon and thalamus perforators. Neurovascular microsurgery allows preserving cerebral blood flow by revascularization while achieving better aneurysm occlusion rates than endovascular therapies. We suggest a novel IC-IC bypass technique, designed to treat P2 or P3 aneurysms that could require PVO, which consist in an end-to-side anastomosis of the third segment of both PCA. Methods: Twelve injected cadaveric heads were implemented in this simulation. A supracerebellar-infratentorial approach was conducted. PCA, in its quadrigeminal segment, P3, were bilaterally dissected characterizing the perforating arteries pattern. PCA were proximally clipped at the distal edge of P2B, cut, transposed and anastomosed in an end-to-side fashion to the contralateral PCA. Distances between both PCA at the quadrigeminal point (QD), buffer lengths(BL), calibers, depth of work(DoW) and causes preventing the bypass were registered. Results: The P3-P3 bypass was feasible in 50% of the cases. Caliber match for P3-P3 bypass was optimal (Donor: 1.64 mm and recipient: 1.63 mm). The causes preventing performing the bypass were an unfavorable branching pattern in 90% of the cases and an insufficient BL(10%) . Mean QD was 15.5mm(SD: 2.1). To successfully overcome this distance, or BL, the recipient vessel was transposed 20.1mm(SD: 2.1). Mean DoW was:60.3mm. Conclusion: Hereby we suggest a novel technique of bypass for the revascularization of the occipital lobe through an end-to-side P3-P3 anastomosis. The results prove the feasibility of this novel bypass and offer an alternative bail out to simple PVO for an optimal treatment of complex PCA aneurysms. To our knowledge this is the first IC-IC in situ bypass suggested for this territory.