Bone anchoring device

Abstract

A bone anchoring device includes an anchoring element having a shank to be anchored in a bone or a vertebra, a rod for connecting at least two anchoring elements, the rod being made of an elastic material. The bone anchoring device further includes a receiving part being connected to the shank for receiving the rod, a seat for the rod being provided in the receiving part the seat having a rod contacting surface, and a locking device cooperating with the receiving part for fixation of the rod in the seat. The locking device includes a rod contacting surface, wherein the rod contacting surface of the seat and/or the rod contacting surface of the locking device includes an engagement structure for engaging the rod, the engagement structure having an asymmetric cross section.

1 . (canceled) 
     
     
         2 . (canceled) 
     
     
         3 . The bone anchoring device according to  claim 16 , wherein the engagement structure is a rib-like projection. 
     
     
         4 . The bone anchoring device according to  claim 16 , wherein the engagement structure comprises two rib-like projections spaced apart from a center of the rod contacting surface. 
     
     
         5 . The bone anchoring device according to  claim 16 , wherein the rod is held in place by a frictional force exerted by the locking device with an indirect form-fit contribution with the engagement structure engaging the rod. 
     
     
         6 . The bone anchoring device according to  claim 16 , wherein the receiving part is fixedly connected to the shank so as to provide a monoaxial bone anchoring device. 
     
     
         7 . The bone anchoring device according to  claim 6 , wherein the receiving part has a U-shaped recess forming two open legs, and wherein the seat is provided at the bottom of the recess. 
     
     
         8 . The bone anchoring device according to  claim 16 , wherein the receiving part is pivotably connected to the shank so as to provide a polyaxial bone anchoring device. 
     
     
         9 . The bone anchoring device according to  claim 8 , wherein the seat is provided in a pressure element which is movable in the receiving part, and which locks the angular position of the bone anchoring element if pressure is exerted on the pressure element. 
     
     
         10 . The bone anchoring device according to  claim 16 , wherein the locking device is a one-piece locking device which has the engagement structure at its lower side facing the rod. 
     
     
         11 . The bone anchoring element according to  claim 16 , wherein the locking device is a two piece locking device comprising a set screw and a filling piece between the set screw and the rod, the engagement structure being provided at the lower side of the filling piece. 
     
     
         12 . The bone anchoring device according to  claim 16 , wherein the rod is made of a free-flowing material. 
     
     
         13 . The bone anchoring device according to  claim 16 , wherein the rod is made of an elastomeric material. 
     
     
         14 . The bone anchoring device according to  claim 16 , wherein the height of the projection varies over a length thereof in such a way that a uniform pressure distribution is obtained when the projection presses against the rod. 
     
     
         15 . The bone anchoring device according to  claim 14 , wherein the projection comprises a portion including the center and wherein the height in the portion decreases towards the center. 
     
     
         16 . A bone anchoring device comprising:
 an anchoring element having a shank to be anchored in a bone or a vertebra;   a rod for connecting at least two anchoring elements, the rod being made of an elastically compressible material;   a receiving part being connected to the shank for receiving the rod;   a seat for the rod being provided in the receiving part, the seat having a rod contacting surface;   a locking device cooperating with the receiving part for fixation of the rod in the seat, the locking device comprising a rod contacting surface;   wherein at least one of the rod contacting surface of the seat and the rod contacting surface of the locking device comprises an engagement structure for engaging the rod, the engagement structure comprising a projection having two ends and extending over a length from one end to the other end and wherein a height of the projection varies over the length   wherein the projection comprises a center between the two ends and a portion including the center, wherein a height of the projection in the portion decreases towards the center.   
     
     
         17 . The bone anchoring device according to  claim 16 , wherein rod is made of an elastomeric material. 
     
     
         18 . (canceled) 
     
     
         19 . (canceled) 
     
     
         20 . A method of attaching a bone anchoring device to a bone or vertebrae, the bone anchoring device comprising an anchoring element having a shank to be anchored in a bone or a vertebra, a rod for connecting at least two anchoring elements, the rod being made of an elastically compressible material, a receiving part being connected to the shank for receiving the rod, a seat for the rod being provided in the receiving part, the seat having a rod contacting surface, a locking device cooperating with the receiving part for fixation of the rod in the seat, the locking device comprising a rod contacting surface, wherein at least one of the rod contacting surface of the seat and the rod contacting surface of the locking device comprises an engagement structure for engaging the rod, the engagement structure comprising a projection having two ends and extending over a length from one end to the other end and wherein a height of the projection varies over the length in such a way that a uniform pressure distribution is obtained when the projection presses against the rod, wherein the projection comprises a center between the two ends and a portion including the center, wherein a height of the projection in the portion decreases towards the center, the method comprising:
 attaching the bone anchoring element to a bone or vertebrae;   connecting the rod to the receiving part;   securing the rod to the receiving part with the locking device;   wherein securing the rod with the locking device comprises the engagement structure engaging the rod to fix the rod to the receiving part; and   wherein the engagement structure provides a uniform pressure distribution when the projection of the engagement structure presses against the rod to fix the rod to the receiving part.