Height-adjustable intervertebrae implant

Abstract

An intervertebral implant for insertion between two vertebrae is disclosed. A first part has a first contact surface extending between its two ends a first guide surface extending out from the first contact surface. A second part has a second contact surface extending between its ends, and a second guide surface recessed into the second contact surface. The first guide surface and the second guide surface cooperate so that the first contact surface of the first part can slide relative to the second contact surface of the second part with a translation motion guided by the cooperating structures of the first and second guide surfaces. The height of the intervertebral implant can be altered by shifting the first part and the second part relative to each other by moving the contact surfaces relative to each other by using the cooperating guide surfaces.

1 . An intervertebral implant comprising:
 a first part having a first end, a second end, a first contact surface provided between the first and second ends and a first guide surface extending out from the first contact surface; and   a second part having a third end, a fourth end, a second contact surface provided between the third and fourth ends, and a second guide surface recessed into the second contact surface;   the first guide surface and the second guide surface comprising cooperating structures so that the first contact surface of the first part can slide relative to the second contact surface of the second part with a translation motion guided by the cooperating structures of the first and second guide surfaces.   
   
   
       2 . The intervertebral implant according to  claim 1 , wherein the first part further comprises a first base surface opposite to said first contact surface and a first plane parallel to said first contact surface intersects a second plane parallel to said first base surface forming an inclination angle of contact α; and
 wherein the second part further comprises a second base surface opposite to said second contact surface and a third plane parallel to said second contact surface intersects a fourth plane parallel to said second base surface forming an inclination angle of contact α.   
   
   
       3 . The intervertebral implant according to  claim 1 , wherein the first and second contact surfaces and the first and second guide surfaces comprise an arcuate shape. 
   
   
       4 . The intervertebral implant according to  claim 1 , wherein said first and second parts are straight. 
   
   
       5 . The intervertebral implant according to  claim 1 , further comprising a terminal stop. 
   
   
       6 . The intervertebral implant according to  claim 2 , wherein said implant comprises a material and said angle α is determined based on the material and the surface properties of the first and second contact surfaces such that a self-locking mechanism between the first part and the second part is effected. 
   
   
       7 . The intervertebral implant according to  claim 1 , wherein one of the first guide surface and the second guide surface comprises a ridge and the other of the first guide surface and the second guide surface comprises a groove. 
   
   
       8 . The intervertebral implant according to  claim 7 , wherein the first and second contact surfaces, the ridge and the groove each comprise an arcuate shape. 
   
   
       9 . The intervertebral implant according to  claim 7 , wherein the groove is located in the second contact surface and extends from the third end to a pre-set distance from the fourth end of the second contact surface, thereby providing a terminal stop. 
   
   
       10 . The intervertebral implant according to  claim 6 , wherein the ridge comprises a first cross-section and the groove comprises a second cross-section, the first cross-section comprising a shape selected from the group comprising a dovetail-shape, a T-shape, a rectangle, a square or a semicircle, and the second cross-section comprises a complementary shape to the first cross-section shape such that the ridge and groove cooperate. 
   
   
       11 . The intervertebral implant according to  claim 1 , said implant further comprising an orifice or a recess. 
   
   
       12 . The intervertebral implant according to  claim 1 , wherein the first contact surface and/or the second contact surface comprise a roughened surface or a step-like surface. 
   
   
       13 . The intervertebral implant according to  claim 1 , wherein the first part comprises a first base surface and the second part comprises a second base surface, wherein at least one of first and second base surfaces comprise groove-shaped recesses. 
   
   
       14 . The intervertebral implant according to  claim 1 , wherein said first part and said second part are formed from a polymer. 
   
   
       15 . The intervertebral implant according to  claim 14 , wherein said polymer is polyetheretherketone. 
   
   
       16 . The intervertebral implant according to  claim 14 , wherein said polymer is polytetrafluoroethylene. 
   
   
       17 . The intervertebral implant according to  claim 1 , wherein said first and second part are formed from a body compatible metal or metal alloy. 
   
   
       18 . A method of stabilizing two spaced vertebrae, the method comprising:
 providing an intervertebral implant comprising:
 a first part having a first end, a second end, a first contact surface extending between the first and second ends and a first guide surface extending out from the first contact surface; and 
 a second part having a third end, a fourth end, a second contact surface extending between the third and fourth ends, and a second guide surface recessed into the second contact surface; 
 the first guide surface and the second guide surface comprising cooperating structures so that the first contact surface of the first part can slide relative to the second contact surface of the second part with a translation motion guided by the cooperating structures of the first and second guide surfaces; 
   adjusting the height of the implant by connecting the second end of the first part with the third end of the second part and moving the first contact surface relative to the second contact surface to bring the first end of the first part closer to the fourth end of the second part using the cooperating guide surfaces; and   inserting the adjusted height implant between the vertebrae in need of stabilization.   
   
   
       19 . The method according to  claim 18 , the method further comprising fixing the two spaced vertebrae relative to each other.