Instrumentation and methods for use in implanting a cervical disc replacement device

Abstract

Instrumentation for implanting an intervertebral disc replacement device includes a retaining device comprising a threaded attachment member for threaded engagement with the at least one mounting screw hole in the flange of the intervertebral disc replacement device, and a head flange extending from the threaded attachment member, wherein a portion of the head flange is in part abuttingly received against a side of the flange of the intervertebral disc replacement device and another portion of the head flange is partially received over a portion of the bone screw to prevent the bone screw from backing out of the at least one bone screw hole when the retaining device is fully engaged with the intervertebral disc replacement device. The invention also comprises a method of preventing a bone screw from backing out of a bone screw hole in an intervertebral disc replacement device, comprising the steps of inserting a retaining device into a mounting hole in the intervertebral disc replacement device and tightening the retaining device in the mounting hole such that a portion of a head flange of the retaining device becomes flatter against a portion of the intervertebral disc replacement device and another portion of the head flange of the retaining device abuts against a portion of the bone screw.

1 . A method of replacing an intervertebral disc between upper and lower vertebral bodies comprising the steps of:
 providing an intervertebral disc replacement device including an upper element having a first articulation surface and a first flange with a first bone screw hole and a first mounting hole formed therethrough, and a lower element having a second articulation surface and a second flange with a second bone screw hole and a second mounting hole formed therethrough;   inserting the intervertebral disc replacement device between the upper and lower vertebral bodies so that the upper element contacts the upper vertebral body and the lower element contacts the lower vertebral body;   inserting a first bone screw through the first bone screw hole and into the upper vertebral body;   inserting a first attachment member of a first retaining device through the first mounting hole so that a first head flange of the first attachment member is at least partially received over the first bone screw to prevent the first bone screw from backing out of the first bone screw hole;   inserting a second bone screw through the second bone screw hole and into the lower vertebral body; and   inserting a second attachment member of a second retaining device through the second mounting hole so that a second head flange of the second attachment member is at least partially received over the second bone screw to prevent the second bone screw from backing out of the second bone screw hole,   wherein the first and second head flanges include solid portions and stress relief areas and the inserting of the first and second attachment member steps include flexing the first and second head flanges.   
     
     
         2 . The method of  claim 1 , wherein the inserting of the first and second attachment members steps include threading the first attachment member into the first mounting hole and the second attachment member into the second mounting hole. 
     
     
         3 . The method of  claim 1 , wherein the stress relief areas of the first and second head flanges are wholly contained within the confines of and do not extend through outer perimeters of the first and second head flanges. 
     
     
         4 . The method of  claim 3 , wherein the stress relief areas are located at points on the first and second head flanges other than at the center thereof. 
     
     
         5 . The method of  claim 1 , wherein the first and second head flanges are of a convex construction from an orientation taken in relation to the first and second attachment members. 
     
     
         6 . The method of  claim 5 , wherein the first and second head flanges flex in such a manner as to cause the convex construction thereof to become flatter when the first and second retaining devices are fully engaged with the upper and lower elements of the intervertebral disc replacement device, wherein the substantially flattened condition of the first and second head flanges causes the first and second head flanges to contact a greater areas of the first and second bone screws. 
     
     
         7 . The method of  claim 1 , further comprising the steps of:
 inserting a third bone screw through a third bone screw hole formed in the upper element and into the upper vertebral body; and   inserting a fourth bone screw through a fourth bone screw hole formed in the lower element and into the lower vertebral.   
     
     
         8 . The method of  claim 7 , wherein the inserting of the first attachment member causes the first head flange to at least partially be received over the first and third bone screws to prevent the first and third bone screws from backing out of the first and third bone screw holes, and the inserting of the second attachment member causes the second head flange to at least partially be received over the second and fourth bone screws to prevent the second and fourth bone screws from backing out of the second and fourth bone screw holes. 
     
     
         9 . The method of  claim 1 , wherein the first and second head flanges each include at least two stress relief areas. 
     
     
         10 . The method of  claim 9 , wherein the first and second head flanges each include at least four stress relief areas. 
     
     
         11 . The method of  claim 1 , wherein the inserting of the intervertebral disc replacement device step includes retaining the first and second articulation surfaces in registration with one another. 
     
     
         12 . The method of  claim 12 , wherein the first articulation surface includes a first concave surface and a first convex surface and the second articulation surface includes a second concave surface and a second convex surface, the first concave and second convex surfaces and first convex and second concave surfaces contacting one another. 
     
     
         13 . A method of implanting an intervertebral disc replacement device including an upper element having a first articulation surface and a first flange with a first bone screw hole and a first mounting hole formed therethrough, and a lower element having a second articulation surface and a second flange with a second bone screw hole and a second mounting hole formed therethrough, the method comprising the steps of:
 inserting the intervertebral disc replacement device between the upper and lower vertebral bodies so that the upper element contacts the upper vertebral body and the lower element contacts the lower vertebral body, the first and second articulation surfaces remaining in registration with each other;   inserting a first bone screw through the first bone screw hole and into the upper vertebral body;   inserting a first retaining device having a first attachment member and a first head flange through the first mounting hole so that the first head flange at least partially contacts the first bone screw to prevent the first bone screw from backing out of the first bone screw hole;   flexing the first head flange so that first head flange contacts a greater area of the first bone screw;   inserting a second bone screw through the second bone screw hole and into the lower vertebral body; and   inserting a second retaining device having a second attachment member and a second head flange through the second mounting hole so that the second head flange at least partially contacts the second bone screw to prevent the second bone screw from backing out of the second bone screw hole;   flexing the second head flange so that second head flange contacts a greater area of the second bone screw,   wherein the first and second head flanges include solid portions and stress relief areas.   
     
     
         14 . The method of  claim 13 , wherein the inserting of the first and second attachment members steps include threading the first attachment member into the first mounting hole and the second attachment member into the second mounting hole, and the flexing steps include tightening the first attachment member into the first mounting hole and the second attachment member into the second mounting hole 
     
     
         15 . The method of  claim 13 , wherein the stress relief areas of the first and second head flanges are wholly contained within the confines of and do not extend through outer perimeters of the first and second head flanges. 
     
     
         16 . The method of  claim 15 , wherein the stress relief areas are located at points on the first and second head flanges other than at the center thereof. 
     
     
         17 . The method of  claim 13 , wherein the first and second head flanges are of a convex construction from an orientation taken in relation to the first and second attachment members. 
     
     
         18 . The method of  claim 17 , wherein the flexing steps include flattening the convex construction of the first and second head flanges. 
     
     
         19 . The method of  claim 13 , further comprising the steps of:
 inserting a third bone screw through a third bone screw hole formed in the upper element and into the upper vertebral body; and   inserting a fourth bone screw through a fourth bone screw hole formed in the lower element and into the lower vertebral.   
     
     
         20 . The method of  claim 19 , wherein the inserting of the first attachment member causes the first head flange to at least partially contact the first and third bone screws to prevent the first and third bone screws from backing out of the first and third bone screw holes, and the inserting of the second attachment member causes the second head flange to at least partially contact the second and fourth bone screws to prevent the second and fourth bone screws from backing out of the second and fourth bone screw holes. 
     
     
         21 . The method of  claim 13 , wherein the first and second head flanges each include at least two stress relief areas. 
     
     
         22 . The method of  claim 21 , wherein the first and second head flanges each include at least four stress relief areas. 
     
     
         23 . The method of  claim 13 , wherein the first articulation surface includes a first concave surface and a first convex surface and the second articulation surface includes a second concave surface and a second convex surface, the first concave and second convex surfaces and first convex and second concave surfaces contacting one another. 
     
     
         24 . A method of implanting an intervertebral disc replacement device including an upper element having a first articulation surface and a first flange with a first bone screw hole and a first mounting hole formed therethrough, and a lower element having a second articulation surface and a second flange with a second bone screw hole and a second mounting hole formed therethrough, the method comprising the steps of:
 inserting the intervertebral disc replacement device between the upper and lower vertebral bodies so that the upper element contacts the upper vertebral body and the lower element contacts the lower vertebral body, a first concave surface of the first articulation surface remaining in registration with a second convex surface of the second articulation surface and a first convex surface of the first articulation surface remaining in registration with a second concave surface of the second articulation surface;   inserting a first bone screw through the first bone screw hole and into the upper vertebral body;   threading a first retaining device having a first attachment member and a first head flange through the first mounting hole so that the first head flange at least partially contacts the first bone screw to prevent the first bone screw from backing out of the first bone screw hole;   tightening the first retaining device so that the first head flange flexes and contacts a greater area of the first bone screw, the first head flange including a plurality of stress relief areas that aid in the flexing of the first head flange;   inserting a second bone screw through the second bone screw hole and into the lower vertebral body; and   threading a second retaining device having a second attachment member and a second head flange through the second mounting hole so that the second head flange at least partially contacts the second bone screw to prevent the second bone screw from backing out of the second bone screw hole;   tightening the second retaining device so that the second head flange flexes and contacts a greater area of the second bone screw, the second head flange including a plurality of stress relief areas that aid in the flexing of the second head flange.   
     
     
         25 . The method of  claim 24 , further comprising the steps of:
 inserting a third bone screw through a third bone screw hole formed in the upper element and into the upper vertebral body; and   inserting a fourth bone screw through a fourth bone screw hole formed in the lower element and into the lower vertebral, wherein the threading of the first retaining device causes the first head flange to at least partially contact the first and third bone screws to prevent the first and third bone screws from backing out of the first and third bone screw holes, and the threading of the second retaining device causes the second head flange to at least partially contact the second and fourth bone screws to prevent the second and fourth bone screws from backing out of the second and fourth bone screw holes.