A surgical ring is suitable for implantation in a human or animal body and to surround a biological organ forming a bag in order to modify the flow area thereof. The ring comprises a hose having an inner surface intended for engaging with the biological organ in order to modify the section thereof and an outer surface opposite the former, and a belt mounted on and along the outer surface and attached to the latter. The hose and the belt are respectively provided with a first and second matching assembly that interact mechanically in order to substantially prevent any sliding of the belt along the outer surface.
