Abstract: Plate and screw assembly for fixing bone pieces, the assembly including a plate and at least one screw, the plate including at least one orifice that defines a cavity for housing a head of the screw and the screw head is provided with a resilient retainer for retaining the head of the screw within the cavity with free pivotal movement but prevented from any axial movement, so that the screw is prevented from moving out of the orifice of the plate.

Abstract: A bone fixation device, e.g., a pedicle screw or hook, having a threaded head is secured to a rod by a coupler comprising a pair of elements, one having a bifurcated body with rod receiving bores and a flange with a bore for receiving the threaded head. A second element has a body between the bifurcated body portions hinged to the other element by a pivot pin. A flange with a head receiving bore extends from the second element body juxtaposed and aligned with the other element flange bore. The second element body has a rod receiving bore offset relative to the rod receiving bores of the body portions. A nut screwed to the head clamps the overlying pivoting flanges together clamping the pivoting offset rod bores to the received rod. In a second embodiment, the second element body is a hook. The hook and body portions form offset rod receiving openings pivoting about the received rod and which clamp the rod when the flanges are clamped together via the nut and head.

Abstract: Bone fixation element and transverse linking bridge for a spinal column fixation assembly, in which the fixation element and the bridge allow to accommodate more easily the connections between the parts forming the bone fixation assembly, which would make difficult the alignment and interconnection of each of the assembly connecting parts, the fixation element comprising a hook or screw presenting an intermediate portion of spherical form that may be coupled to a seat portion of a coupling piece between the fixation element and the bar of the fixation assembly. The transverse linking bridge comprising one or two bridge parts which have at their ends a coupling hook in which a pivoting spherical insert is placed, which adjusts the deviations of the respective bar during fastening.

Abstract: Bone fixation device for keeping two or more bone pieces together, either pieces of a broken bone or two distinct bones, for undergoing junction of the pieces by natural welding, the device being capable of immobilizing flat or round bones, long or short bones, parts of a broken femur or two contiguous vertebrae, the device comprising a fixation plate and fixation screws, the plate having orifices for passing the screws through the plate and fastening the screws into the bone tissue, a screw blocking or locking mechanism being provided in the plate to block the screws in the fastening position once the screws have been passed through the plate and screwed into the bone pieces, for preventing the screws from unscrewing from the bone pieces and moving out of the fixation plate once and after the fixation plate and the screws have been firmly installed in the bones, with the risk of entering into contact with the patient inner tissues, muscles or organs, the blocking mechanism being easily operated by a surgeon