Open surgery stent graft

In the past AAAs were treated by open surgery which involved a large abdominal incision and implantation of a synthetic prosthesis as described in a previous chapter. Today, with the development of the endovascular stent graft, the less invasive EVAR is approach that has several advantages over the open procedure, chief among which is a lower perioperative morbidity and mortality rate (Teufelsbauer, 2002 Biebl, 2005). 

Therefore, methods such as hybrid procedures, sandwiches, chimneys and snorkels, and on-site and in situ fenestrations have been developed. Hybrid procedures involve open surgery to create bypasses to the renal and mesenteric arteries, followed by covering all the branches with a conventional stent graft so as to extend the landing zone. Chimneys or snorkels involve placing a parallel, smaller sized covered stent into the renal arteries so that blood flows to the kidneys. However, there is concern that endoleaks will cause blood to flow between the aortic stent-graft and the renal chimney. There is a similar concern when more than one bifurcated device is inserted or sandwiched in the same aneurysmal sac so as to provide blood flow to several extensions simultaneously. The body of such devices needs to take on a D shaped cross-section so as to avoid endoleaks between the devices and the aneurysmal sac. 

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