Necessary treatment, treatment device and manufacturing METHOD

This kit comprises: - a first implant (16) defining a window (26); - a second implant (18) having a second tubular body (42) intended to be arranged in the window (26). The second implant (18) includes a retaining member of the second implant (18) relative to the first implant. The kit comprises a ring (20) retaining the second implant (18) attached to the first tubular body (22) in the window (26) and defining an introduction passage (60) of the second implant (18). The retaining ring (20) is elastically deformable in the window (26) to allow a reversible increase of at least 20%, preferably at least 30% of the outer contour of the introduction passage (60).