Abstract: Devices that facilitate insertion of tube-like structures, e.g., catheters and other medical devices, into passages in mammalian bodies, e.g. in the human body. Devices according to various embodiments of the invention provide greater stiffness and/or rigidity to elongated tube-like structures. According to some embodiments, a portion or the entire insertion facilitation device can be removed from the tube-like structure after insertion thereof. According to some embodiments of the invention, an insertion facilitation device comprises a releasable engagement arrangement to releasably engage the stiffener and a tube-like structure to inhibit or prevent relative motion between the stiffener and tube-like structure.