| abstract |
A disc prosthesis (P, P′, P″) for use on a pair of adjacent vertebrae (V, V′) comprises upper and lower plates ( 10/12, 30/32, 106/108 ) adapted to be mounted respectively to adjacent upper and lower vertebrae (V, V′) typically using screws that extend through holes defined in the plates ( 10/12, 30/32, 106/108 ) and into the vertebrae (V, V′), a joint mechanism ( 16, 36, 100 ) linking the upper and lower plates, and a damping system ( 26, 104 ). The joint mechanism and the damping system are adapted to allow for biased relative movements between the upper and lower vertebrae (V, V′). For instance, the joint mechanism comprises a substantially V-shaped joint ( 16 ) extending at least partly in an intersomatic space (S) defined between the upper and lower vertebrae (V, V′) and in a substantially axial plane thereof. The V-shaped joint ( 16 ) has a pair of arms ( 18, 20 ) adapted to pivot relative to each other thereby allowing for at least one of an extension and a contraction movement between the upper and lower vertebrae (V, V′), with the damping system ( 26 ) being adapted to act on the V-shaped joint ( 16 ). Alternatively, the joint mechanism comprises an anterior guillotine-type, or cigar-cutter, joint ( 36 ) having engaged upper and lower members ( 30, 32 ) adapted for sliding relative movements therebetween along an axial orientation of the vertebrae (V, V′), and with the damping system being adapted to act on the guillotine-type joint ( 36 ). The joint mechanism can also include a flexible deformable jacket ( 100 ) lodged in the intersomatic space (S) and defining a chamber ( 102 ) adapted to receive therein a dampening fluid, such as a hydrogel ( 104 ). |