| 摘要 |
Disclosed is an apparatus for replacing at least a portion of an intervertebral disc in a spinal column between endplates of a first vertebral body and a second vertebral body of a spinal column, the apparatus comprises a first member with a first vertebral contact surface for engagement with the first vertebral body endplate, and a first articulation surface. The apparatus also includes a second member with a second vertebral contact surface for engagement with the second vertebral body endplate, and a second articulation surface. An intervertebral spacing is defined as the axial component of a line extending between a centroid of the first vertebral contact surface and a centroid of the second vertebral contact surface. The first articulation surface and the second articulation surface form at least part of an articulation arrangement configured such that, when loaded with compressive axial force the first and second vertebral contact surfaces are supported against the compressive force to ensure a predefined minimum intervertebral spacing. The second member is displaceable relative to the first member in motion corresponding to axial rotation, anterior-flexion and posterior extension, and lateral bending, each of the motions having a corresponding range of motion. The intervertebral spacing increases as a smooth function of angular displacement from a neutral position over at least part of the range of motion in each direction for each of the axial rotation, anterior-flexion and posterior extension and lateral flexion, thereby providing non-impact motion attenuation.
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