A device (100, 500, 600, 700, 800, 900) for fusion of the distractible intervertebral body adapted for implantation in an intervertebral disc space of a patient having a first support surface (102) configured to interact with an end plate of an upper vertebra of the intervertebral disc space and a second support surface (104) configured to interconnect with an end plate of a lower vertebra of the intervertebral disc space, where the device includes: at least one coaxial helical gear sleeve mechanism disposed between the first support surface (102) and the second support surface (104), characterized in that the coaxial helical gear sleeve mechanism includes: a post (111, 112, 511, 621) having a surface (113, 115, 911) threaded outside on a part of the post protruding inward from one of the first support surface and the second support surface； and a corresponding sleeve (120, 130, 520, 620, 720, 920) configured to surround the post and having: an inner surface (122, 132) threaded into one part of the sleeve protruding inward from the other of the first support surface and the second support surface and configured to interconnect with the threaded outer surface of the post； and an outer gear surface (124, 134, 922) in a portion of the sleeve, the outer gear surface defined in a thread (121, 131, 921) extending in a helical pattern along a sleeve height ； and a drive mechanism having a surface configured to interact with the outer gear surface of the sleeve and drive it, so that the selective operation of the drive mechanism causes a distraction of the first supporting surface (102) and the second surface ( 104) of support with respect to the superior vertebra and the inferior vertebra of the intervertebral disc space due to a telescopic expansion resulting from the translation of the sleeve with respect to one of the first support surface and the second support surface simultaneously with the translated post with respect to the sleeve.Un dispositivo (100, 500, 600, 700
