| 摘要 |
A disc replacement spinal interbody fusion device is provided having a central sleeve with oppositely left and right-hand threaded axial bores with different diameters. Circumferential threaded apertures are located on the sleeve and open into the sleeve bores. The device has two opposing plates which are oval-shaped and centrally, axially bored. Each plate has a perpendicular shaft with an axial bore which communicates with the shaft bore. The first shaft has external left-hand threads and the second shaft has external right-hand threads, each to mate with different bores of the sleeve. The outside diameter of the first shaft is smaller than the inside diameter of the second shaft, allowing the two shafts to axially engage. The spinal interbody fusion device operates like a turnbuckle, vertically expanding when the sleeve is rotated in one direction and retracting when the sleeve is rotated in the opposite direction. The assembled device defines an open channel axially. Once the fusion device is set at its proper height, set screws are threaded into circumferential apertures of the sleeve to compress against the shaft threads of each plate to maintain a fixed height. In situ, axial loading of the spinal column upon the fusion device creates a bending moment manifested by a flexing action of the plates to generate opposing axial directional forces which replicate the physiological function of shock absorption, load bearing and load transmission.
|
