Abstract: A medical device to be inserted in a defect blood vessel, body cavity, or body duct for treatment thereof is disclosed, wherein it comprises an essentially cylindrically formed elongated resilient sheath device (2) wherein it has a distal end (3) and a proximal end (4), wherein said sheath device (2) along its circumferential surface in the axial direction is provided with a slotted opening (5) having connection with a first bore (6) arranged in the axial direction of said sheath device (2), said first bore (6) having the ability to house an elongated fiber body (7), wherein said sheath device (2) has the ability to be clamped around a major part of the perimeter of said fiber body (7), and wherein said sheath device (2) in its axial direction also is provided with a second bore (8) having the ability to house an injection means (9), as well as a kit containing said medical device, and a method for treatment of defective blood vessels, body cavities, and body ducts by use of said medical device.