LAUSR

Complex revascularization procedures sometimes have to go beyond the standard STA-MCA bypass procedure in order to deliver adequate amounts of blood flow, either for flow augmentation or flow replacement. Here, revascularization procedures with large caliber vessel grafts, such as the radial artery or saphenous vein, are applied. For those, the proximal anastomosis is typically located at the external carotid artery, the internal maxillary artery, or a prominent stump of the superficial temporal artery, and the distal anastomosis is located at the internal carotid artery of M1/M2 segments which will provide a good drain of the delivered blood. The typical use case for flow replacement with a large caliber graft is the reconstruction of the vascular tree in order to treat a complex aneurysm. The majority of complex aneurysms are giant, fusiform, or partially thrombosed/calcified, with the need for sacrificing the diseased vessel segment and revascularizing the dependent vascular territory with a bypass, as the only durable strategy for aneurysm exclusion. The inherent risk of these intracranial anastomoses to proximal segments of major brain arteries is the need for temporary occlusion and concomitant temporary ischemia times. This is why the group around Prof Tulleken in Utrecht has pioneered techniques to circumvent temporary occlusion over the past decades, by creating an end-to-side anastomosis between large caliber grafts and major intracranial vessels. The first version that entered clinical application and trials was the ELANA (excimer laser–assisted non-occlusive anastomosis) procedure that does not require temporary occlusion of the recipient vessel, potentially allowing for a safer construction of high-flow EC-IC bypass grafts to large proximal arteries (> 2.6 mm) with resultant higher graft flows. Here, the saphenous vein is stitched on the recipient vessel using a platinum ring which flattens and stretches the vessel wall that has been selected as anastomotic site. Then, a laser catheter is inserted through the vein and vacuum suction is applied for 2 min in order to suck the vessel wall within the ring to the tip of the laser catheter. After a good contact between the laser catheter tip and vessel wall has been established, the flap within the ring is lasered out, without the need for temporary vessel occlusion. The ELANA technique has proven to work well for different surgical teams outside Utrecht [1, 2]. A recent prospective multicenter IDE study on high-flow cerebral bypasses for anterior circulation artery aneurysms revealed 30-day morbidity and mortality rates of 19.4% and 5.6% in a difficult-to treat patient group [3]. These rates compare favorably with those rates of morbidity and mortality previously reported in the literature for conventional high flow bypass. However, the ELANA procedure also carries some disadvantages. Among those is the surgical complexity and challenge of the procedure. The transsylvian working corridor is often deep and narrowwhile a minimum of eight microsutures are required to fix the device’s platinum ring to the recipient vessel. Also, it not only about simply placing the sutures but also about placing the sutures in a way that guarantees even distribution of the tension forces on the vessel wall within the ring. Any flaws may lead to damage to surrounding tissues or unsuccessful retrieval of the vessel wall flap. Even in experienced hands, this technique affords a lot of training in the lab and still total suture time may last up to 90 min. This is why the Utrecht group has sought to develop a sutureless alternative for their laser-assisted technique of non-occlusive anastomosis between 2004 and 2010. The results on their first version were published in 2009 and the first clinical application was published in 2018 [4]. Here, the basic idea was to replace the sutured ring with a slide on which the graft is mechanically fixed and which is then pushed and anchored via two pins into the recipient vessel. This would fix and slightly stretch the recipient artery wall within the This article is part of the Topical Collection onVascular Neurosurgery Other