INTERVERTEBRAL IMPLANT
Disclosed is an intervertebral implant ( 1 ) comprising a central axis ( 2 ), a bottom cover plate ( 3 ) and a top cover plate ( 4 ), which are respectively provided with an exterior surface ( 7; 8 ) that extends transversal to the central axis ( 2 ), and a central part ( 10 ). Said central part ( 10 ) is located between the cover plates ( 3; 4 ) and is provided with a sleeve ( 12 ) encompassing a fiber system ( 5 ) that is connected to the cover plates ( 3; 4 ) and is embedded in an enveloping body ( 25 ) made of a homogeneous material. In analogy with the anatomic structure of the natural disk, the inventive intervertebral implant ( 1 ) can transfer occurring compressive forces onto the cover plates ( 3, 4 ) thereof as tensile forces that are applied to the individual fibers of the fiber system ( 5 ) thereof.
1 . An intervertebral implant for implantation between upper and lower vertebrae, the implant having a central axis, the implant comprising:
an upper closing plate having an external surface extending generally transversely to the central axis for contacting at least a portion of the upper vertebra;
a lower closing plate having an external surface extending generally transversely to the central axis for contacting at least a portion of the lower vertebra;
a top cover plate operatively joined to the upper closing plate, the top cover plate including a plurality of first grooves;
a bottom cover plate operatively joined to the lower closing plate, the bottom cover plate including a plurality of second grooves;
a central part located between the top and bottom cover plates;
a fibre system at least partially surrounding the central part, the fibre system at least partially received within the plurality of first and second grooves; and
a sheathing at least partially surrounding the fibre system and the central part, the sheathing being operatively coupled to the top and bottom cover plates.
2 . The intervertebral implant of claim 1 , wherein the fibre system is independently moveable relative to the sheathing.
3 . The intervertebral implant of claim 1 , wherein the fibre system is multi-layered.
4 . The intervertebral implant of claim 1 , wherein the fibre system is formed from at least first and second fibres interwoven with one another.
5 . The intervertebral implant of claim 4 , wherein the first fibres are disposed at a first angle α with respect to the central axis and the second fibres are disposed at a second angle β with respect to the central axis.
6 . The intervertebral implant of claim 5 , wherein the first angle α and the second angle β are between 15 and 60 degrees.
7 . The intervertebral implant of claim 1 , wherein the fibre system is constructed of an ultra high molecular weight polyethylene (UHMWPE) material.
8 . The intervertebral implant of claim 1 , wherein the fibre system is secured to the top and bottom cover plates by weaving the fibre system into and out of the plurality of first and second grooves.
9 . The intervertebral implant of claim 1 , wherein the upper and lower closing plates are constructed of one of a titanium and a titanium alloy.
10 . The intervertebral implant of claim 9 , wherein the external surface of the upper and lower closing plates include a macroscopic structure for adhering the implant to the upper and lower vertebrae, respectively.
11 . The intervertebral implant of claim 1 , wherein the sheathing is constructed of a material selected from a group consisting of polyurethane, silicone rubber, polyethylene, polycarbonate urethane and polyethylene terephthalate.
12 . The intervertebral implant of claim 1 , wherein the central part is substantially cylindrical.
13 . The intervertebral implant of claim 12 , wherein the central part includes a top surface and a bottom surface, the top surface of the central part contacting the top cover plate and the bottom surface of the central part contacting the bottom cover plate.
14 . An intervertebral implant for implantation between upper and lower vertebrae, the implant comprising:
an upper substantially rigid closing plate having an external surface and an internal surface, the external surface of the upper closing plate contacting at least a portion of the upper vertebra in an implanted position;
a lower substantially rigid closing plate having an external surface and an internal surface, the external surface of the lower closing plate contacting at least a portion of the lower vertebra in the implanted position;
a top cover plate mechanically joined to the upper closing plate, the top cover plate having a top surface and a bottom surface;
a bottom cover plate mechanically joined to the lower closing plate, the bottom cover plate having a top surface and a bottom surface;
an elastic core located between the bottom surface of the top cover plate and the top surface of the bottom cover plate;
a fibre system surrounding the elastic core and joined to the top and bottom cover plates; and
a sheathing at least partially surrounding the fibre system and joined to the top and bottom cover plates, wherein the fibre system and the sheathing are independently moveable with respect to one another.
15 . The intervertebral implant of claim 14 , wherein the fibre system is independently moveable with respect to the core.
16 . The intervertebral implant of claim 14 , wherein the fibre system includes a plurality of interwoven fibres.
17 . The intervertebral implant of claim 16 , wherein the top and bottom cover plates include a plurality of grooves for receiving at least a portion of the interwoven fibres.
18 . The intervertebral implant of claim 17 , wherein the fibre system is at least partially adhered to the top and bottom cover plates by weaving the fibre system into and out of the plurality of grooves.