Sentence:  In selected cases where there is advanced (TASC) D aorto-iliac occlusive disease, treatment with a <WSD>unibody</WSD> stent-graft positioned at the aortic bifurcation is a safe and effective treatment. 
Meaning of the word marked with <WSD> tags:  A shell that is the principal source of structural strength of an object; also, its design and construction.