Implantable vertebral arthrodesis device (1, 18, 34) for the fusion of two supra and underlying vertebrae, comprising: a. an anterior part (2, 23, 36) comprising an upper support area (2a, 23c) suitable for receiving the lower part (3) of the upper sheet (4) of the overlying vertebra (5) and a lower area of support (2b, 23d) suitable to receive the upper part (6) of the lower lamina (7) of the underlying vertebra (8), the upper (2a) and lower support area (2b) being distant at a minimum height h (h1, h2, h3) for maintenance of an intervertebral separation； b. rigid retention means (9) arranged in relation to the anterior part (2) so as to block the migration of said anterior part (2) towards the spinal canal； c. a rear part (10, 19, 35), in connection with said front part (2), comprising a main housing (11, 28) having a first (11a) and second (11b) openings facing each other and suitable for receive in part the spinous processes (12, 13, 29, 30) respectively of the overlying (5, 26) and underlying (8, 27) vertebrae； characterized in that it comprises: d. a rigid dividing element (14, 25, 41) disposed between the front part (2) and the rear part (10) that delimits, at least in part with the front part (2), an auxiliary housing (15) having a first (15a) and second (15b) openings facing each other, and arranged so that they receive in part the sheets (4, 7) of said overlying (5) and underlying vertebrae (8)； and. a granular osteosynthesis material disposed in said main housing (11) and said auxiliary housing (15).Dispositivo implantable de artrodesis vertebral (1, 18, 34) para la fusión de dos vértebras supra y subyacentes, que comprende: a. una parte anterior (2, 23, 36) que comprende una zona superior de apoyo (2a, 23c) adecuada para recibir la parte inferior (3) de la lámina superior (4) de la vértebra suprayacente (5) y una zona inferior de apoyo (2b, 23d) adecuada para recibir la parte superior (6) de la lámina inferior (7) de la vértebra subyacente (8), estando d
