The kit includes: a first implant (16) defining a window (26), and a second implant (18) including a second tubular body (42) designed to be positioned in the window (26). The second implant (18) includes a retaining member for retaining the second implant (18) relative to the first implant. The kit further includes a retaining ring (20) for retaining the second implant (18) attached on the first tubular body (22) in the window (26) and delimiting an insertion passage (60) for the second implant (18). The retaining ring (20) is elastically deformable in the window (26) to allow a reversible increase of at least 20%, advantageously at least 30%, of the outer contour of the insertion passage (60).
