Fig. 2

A 3.5 mm × 10 mm balloon-expandable Willis covered stent (MicroPort, Shanghai, China) to match the diameters of the aneurismal neck, afferent and efferent artery was precisely placed, so that its proximal end was located at the afferent artery 2 mm below the proximal edge of the aneurismal neck, and its distal end at the efferent artery just about 2 mm over the distal edge of the neck, and then deployed (a). A sub-complete aneurysm exclusion was immediately created, with an intentional endoleak at the distal end of the covered-stent, which reversed blood flow from the basilar artery distal to the Willis (b). An angulation of the proximal basilar artery at the level of the intentional endoleak origin was also noted (b), which was likely to be unfavourable for directing blood flow to the normal middle and distal basilar artery. Two 4.5 mm × 37 mm Enterprise stents (Cordis Neurovascular, Miami, FL, USA) were coaxially deployed within the Willis from the middle basilar artery to the left vertebral artery (c), which changed the angulation (d)