Abstract: A surgical instrument for removal of an immobilizing element includes a main body having a guide tube integral with a fixed handle and having elastic elements for securing the surgical instrument on the head, a locking tube sliding on the guide tube and having elements for immobilizing the surgical instrument on the head, a pusher tube sliding inside the guide tube by way of a mobile handle connected to the fixed handle. The pusher tube has first elements for spacing apart the walls of the head and second elements for immobilizing the connection rod in the base of the head of the bone-anchoring element, and a gripper rod sliding inside the pusher tube and including a gripper device for securing and removal of the immobilizing element from the head of the bone-anchoring element.

Abstract: The surgical instrument according to the present invention comprises a main body (101) comprising a horizontal tube (102) extending by a frame (103) that is formed as an integral unit with a fixed handle (104), a movable handle (105) acting on a driving device (108) guided within the frame (103) and allowing, according to the pressure force applied on the movable handle (105), firstly the immobilization of the surgical instrument (100) on the head (8) of the bone anchoring element (2) and secondly the introduction under the pushing force F of an immobilizing element (104), previously positioned and guided within the tube (102), in the head (8) of the bone anchoring element (2).

Abstract: The invention relates to a method of viewing and controlling the balance of a vertebral column of which one spinal segment is corrected by way of conventional spinal instrumentation. The invention method consists of: determining and calculating the relative three-dimensional position of the upper (UEV) and lower (LEV) end instrumented vertebrae of the corrected spinal segment; determining and calculating the position of the spinal segments which are located above and below the spinal segment corrected by the spinal instrumentation, according to the relative three-dimensional position of the upper (UEV) and lower (LEV) end instrumented vertebrae and viewing the front and side projection of the balance or imbalance of the vertebral column.

Abstract: The intersomatic cage includes a body with a curved profile having at each end on the one hand recesses (8, 9) provided over all the height of the cage, and on the other hand in a direction perpendicular to the direction of the recesses (8, 9) a horizontal notch (14) opening into each recess (8, 9) and permitting temporarily connecting the intersomatic cage to a rod (19) of a cage carrying device (15) ensuring freedom of progressive angular rotation of the cage (1) as a function of its position of introduction between the vertebral bodies (26).

Abstract: The occipital fixation device according to the present invention comprises a first element (10) that is comprised of fixation means for immobilizing in translation and in rotation in a connection rod (5) and engagement means (19, 20) for bone anchoring in the occipital bone (8) and a second element (18) sliding in the first and comprising engagement means (26) supplementing the engagement means (19, 20) of the first element (10) to obtain the bone anchoring of the fixation device (7) in the occipital bone (8).

Abstract: The immobilization device for a connecting rod (2) in an osseous anchoring element (3) of a rachidian implant (4) comprises an osseous anchoring implant (3) comprising retaining means (14, 15) adapted to deform elastically under a pressure force F and a blocking element (5) comprising on the one hand lugs (33, 34) which coact with the retaining means (14, 15) to permit the securement of the blocking element (5) on the osseous anchoring element (3), and on the other hand, a tightening screw (31) permitting immobilizing in rotation and in translation the connecting rod (2) between the osseous anchoring element (3) and the blocking element (5).

Abstract: The rachidian anchoring device with pedicular hooks (2, 4), permitting the emplacement and securement of a connecting rod (3) at the level of each vertebra (9) of a vertebral column, comprises particular hooks (2, 4) provided with securement means for the reception and blocking of a transverse rod (5) connecting said pedicular hooks (2, 4) together and permitting exerting compression between the two pedicular hooks (2, 4) in the direction of the center of the vertebra (9).

Abstract: The invention concerns an intervertebral disc prosthesis comprising an upper plate (2) and a lower plate (3) anchored respectively on the upper end-plate and the lower end-plate of the vertebral bodies of the vertebrae lying above and below a spine, a central core (4) placed between the two plates (2, 3) which have an upper spherical cap (13) and a lower spherical cap (14) co-operating respectively with the spherical impressions (9) arranged in said upper and lower plates, and an annular element (5) made of viscoelastic material which is centred about the core (4) and is urged into contact with protuberances (12) provided on each internal surface (8) of the upper plate (2) and of the lower plate (3) so as to limit and control the bending, inclining and rotating movements of the upper plate (2) and of the lower plate (3) relative to each other and about the core (4), and ensure the positioning stability of the core (4) between the two plates (2, 3) and prevent fibrous deposits from penetrating inside the prost