Spinal osteosynthesis device and preparation method

Abstract

A spinal internal implantation device for osteosynthesis has one or more bars for supporting for moving the spine and at least one implant for connecting the bars and vertebrae. The implant includes a blown anchor attached to a body of the implant and a fixation arrangement for the bars. The fixation arrangement includes a clamp for clamping the bar against internal walls of a channel formed in the body of the implant. At least part of the length of the bars includes a transversal bearing structure that is a cross-section of the bars having at least one flat part of a part having a lower forepost convexity than the rest of the cross section.

1 . An osteosynthesis device comprising:
 a bar comprising a generally rounded portion having a substantially flat longitudinal bearing surface extending substantially parallel to a longitudinal axis of the bar along at least a portion of a length of the bar; and   an implant having a longitudinal axis and comprising
 a channel having an opening along a side of the implant sized to admit the bar in the channel and a clamping wall having a clamping surface complementary to the substantially flat longitudinal bearing surface of the bar, the clamping surface forming a non-zero angle with the longitudinal axis of the implant, and 
 a clamp having a fully open position providing sufficient clearance in the opening of the channel to admit the bar in the channel, a partially open position in which the bar is loosely retained in the channel, and a clamping position in which the bar is completely clamped to the clamping wall of the channel. 
   
     
     
         2 . An osteosynthesis device comprising:
 a bar comprising a rounded surface and a transversal bearing surface, the rounded surface and the transversal bearing surface extending a first length longitudinally along a first portion of the bar, the bar having a first cross-sectional circumference along the first portion of the bar, the first cross-sectional circumference of the bar having a convexity along the rounded surface of the bar, and the transversal bearing surface being selected from the group consisting of surfaces that are generally flat in the cross-sectional circumference, surfaces that have a convexity less than the convexity along the rounded surface of the bar, and surfaces that are concave in the cross-sectional circumference; and   an implant comprising
 a body, 
 a bone anchor, 
 a clamp movably engageable with the body of the implant, the clamp comprising a bearing surface configured substantially complementary to the transversal bearing surface, and 
 a channel having an opening along a side of the implant configured to receive the first portion of the bar with the clamp at least partially engaged with the body of the implant. 
   
     
     
         3 . Device according to  claim 2  wherein the transversal bearing surface of the bar is concave in the cross-sectional circumference and the bearing surface of the clamp is convex. 
     
     
         4 . Device according to  claim 3  wherein the transversal bearing surface of the bar has a first radius of curvature, the bearing surface of the clamp has a second radius of curvature, and the first radius of curvature is greater than the second radius of curvature. 
     
     
         5 . Device according to  claim 2 , wherein the transversal bearing surface of the bar is flat in the cross-sectional circumference and the bearing surface of the clamp is flat. 
     
     
         6 . Device according to  claim 2  wherein the bearing surface of the clamp is articularly disposed by a joint. 
     
     
         7 . Device according to  claim 2  wherein the bar has at least one end portion comprising a longitudinal stop. 
     
     
         8 . Device according to  claim 7  wherein the at least one end portion does not have a transversal bearing surface, and the longitudinal stop comprises a shoulder formed at a junction of said end portion with the first portion of the bar having a transversal bearing surface. 
     
     
         9 . Device according to  claim 2  wherein at an internal wall of the channel of the implant comprises a planar surface configured complementary to a planar face disposed on the bar. 
     
     
         10 . Device according to  claim 9  wherein the clamp has an axis and the planar surface of the implant forms a non-null acute angle with a plane perpendicular to the axis of the clamp, said angle being oriented toward the opening of the channel. 
     
     
         11 . Device according to  claim 2  wherein the clamp has an approach distance, and the approach distance of the clamp and the dimensions of the channel of the implant are sufficiently large to receive bars of different thicknesses. 
     
     
         12 . Device according to  claim 2  wherein the channel has two edges, and the clamp is located along only one of the two edges of the channel. 
     
     
         13 . Device according to  claim 2  wherein the clamp has an axis and a loosening direction, and the opening of the channel defines an extension direction that forms a non-null angle with a plane perpendicular to the axis of the clamp, said angle being oriented in the loosening direction of the clamp. 
     
     
         14 . Device according to  claim 2  wherein the clamp has an axis, the channel has an edge opposite the clamp, and the edge of the channel opposite the clamp forms a nose configured to retain the bar in the channel along a direction perpendicular to the axis of the clamp. 
     
     
         15 . Device according to  claim 2  wherein the channel has at least two edges, and the clamp comprises a clamping screw mountable in a threaded hole passing through one of the edges of the channel. 
     
     
         16 . Device according to  claim 2  wherein the bone anchor of the implant includes a tapered and threaded part configured to be screwed into a vertebra. 
     
     
         17 . An osteosynthesis device comprising:
 a bar comprising a generally rounded portion having a substantially flat longitudinal bearing surface extending substantially parallel to a longitudinal axis of the bar along at least a portion of a length of the bar; and   an implant comprising
 a channel having a clamping wall and an opening along the side of the implant sized to admit the bar in the channel, and 
 a clamp having a substantially flat clamping surface complementary to the substantially flat longitudinal bearing surface of the bar, the clamp having a fully open position providing sufficient clearance in the opening of the channel to admit the bar in the channel, a partially open position in which the bar is loosely retained in the channel, and a clamping position in which the bar is completely clamped to the clamping wall of the channel. 
   
     
     
         18 . The osteosynthesis device of  claim 17  in which the bar comprises plural substantially flat longitudinal bearing surfaces extending substantially parallel to the longitudinal axis of the bar along at least a portion of the length of the bar. 
     
     
         19 . The osteosynthesis device of  claim 18  in which the clamping wall of the channel is complementary to one of the flat longitudinal bearing surfaces of the bar. 
     
     
         20 . The osteosynthesis device of  claim 17  in which the clamp comprises a clamping screw disposed in a threaded hole of the implant.