Closure system for tubular organs

adjustable ring (1) surgically implantable comprising second (4) first end portions (3), and which is designed to be closed around a tubular organ towards its two end parts (3, 4), through a system of closure (2, 5) for adjusting the diameter of said tubular organ by forming a loop forming the first end portion (3) a sleeve having second (7) first open end portions (6) and which is designed to receiving the second end portion (4) of the ring, where the main axis of the sleeve is defined along a direction substantially perpendicular to the main direction of the first end portion (3) of the ring, the second end portion (4) ring further comprising a locking protrusion (2) adapted to hold the sleeve (3) and thereby secure the ring in a closed position, characterized in that the sleeve (3) comprises a hole (5) designed to receive said locking projection (2).