Posterior Fixation System

Abstract

A posterior fixation system includes a saddle member, an anchoring member, an occipital plate, an occipital rod, and a cross-link connector. The anchoring member anchors the saddle member to bone. The saddle member includes a channel that is adapted to receive an orthopedic rod. The saddle member and the anchoring member can be coupled so as to allow multi-axial movement of the members. Connection of individual rods can be accomplished by connecting the rods with the cross-link connector. The occipital plate secures the rods to the occipital bone of the skull. Alternatively, the occipital rod can be secured to the occipital bone.

What is claimed is: 
     
         1 . A multi-axial bone attachment assembly, comprising:
 a saddle member having a plurality of upright portions that define a channel through said saddle member, said saddle member further having a hole therethrough bounded by an inner wall, said hole forming a lower opening in said saddle member;   a bone anchoring member extending through said opening, said bone anchoring member including a head portion and an anchoring portion; and   a washer having a recessed portion for accommodating an orthopedic rod and a radially extending projection, said washer being fitted within said hole of said saddle member and atop said bone anchoring member.   
     
     
         2 . The assembly of  claim 1 , wherein said inner wall includes a groove, and said assembly further comprises a snap-ring fitted in said groove and over said washer to hold said washer in said hole of said saddle member. 
     
     
         3 . The assembly of  claim 2 , wherein said upright portions include threaded portions, and said assembly further comprises a threaded member for engagement with said threaded portions. 
     
     
         4 . The assembly of  claim 3 , wherein said upright portions are internally threaded, and said threaded member is an externally threaded set screw. 
     
     
         5 . The assembly of  claim 4 , wherein said set screw includes an upper surface that is convexly rounded. 
     
     
         6 . The assembly of  claim 3 , wherein said threaded portions have reverse angle threads. 
     
     
         7 . The assembly of  claim 1 , wherein said washer includes an upper portion and a lower portion, said recessed portion being a part of said upper portion and said projection being a part of said lower portion. 
     
     
         8 . The assembly of  claim 7 , wherein said inner wall includes a groove, and said assembly further comprises a snap-ring fitted in said groove and over said lower portion of said washer to hold said washer in said hole of said saddle member. 
     
     
         9 . The assembly of  claim 7 , wherein said upper portion of said washer includes a plurality of recessed portions. 
     
     
         10 . The assembly of  claim 7 , wherein said lower portion of said washer includes a plurality of projections. 
     
     
         11 . The assembly of  claim 1 , wherein said upright portions include threaded portions, and said assembly further comprises a threaded member for engagement with said threaded portions. 
     
     
         12 . The assembly of  claim 1 , wherein said anchoring member is a bone screw. 
     
     
         13 . The assembly of  claim 12 , wherein said bone screw includes a head portion having a convex underside. 
     
     
         14 . The assembly of  claim 13 , wherein said convex underside is spherical. 
     
     
         15 . The assembly of  claim 14 , wherein said bone screw includes a portion having a thread with a load flank and a root surface, and the angle between said load flank and said root surface is acute. 
     
     
         16 . The assembly of  claim 15 , wherein said angle is about 86 degrees. 
     
     
         17 . The assembly of  claim 1 , wherein said anchoring member is a hook member. 
     
     
         18 . The assembly of  claim 17 , wherein said anchoring portion includes a curved portion connected to said head portion and a straight portion connected to said curved portion, said head portion including a plurality of spherical portions for coupling said anchoring member to said saddle member. 
     
     
         19 . The assembly of  claim 1 , wherein said upright portions each have a trough defined therein, said washer including a plurality of projections with each provided in one of said troughs. 
     
     
         20 . The assembly of  claim 1 , wherein said lower opening includes a concave wall portion and a conical wall portion for allowing angular movement of said bone anchoring member. 
     
     
         21 . A spinal implant system, comprising:
 a saddle member having a plurality of upright portions that define a channel through said saddle member, said saddle member further having a transverse hole defined through said upright portions that is transverse with respect to said channel;   a bone anchoring member coupled to said saddle member for anchoring said saddle member to bone; and   an offset member adapted to couple to an orthopedic rod, said offset member having a body adapted to couple to said rod and a coupling member extending from said body through said transverse hole in said upright portions.   
     
     
         22 . The system of  claim 21 , wherein said upright portions include threaded portions, and said system further comprises a threaded member for engagement with said threaded portions. 
     
     
         23 . The system of  claim 22 , wherein said upright portions are internally threaded, and said threaded member includes an externally threaded set screw. 
     
     
         24 . The system of  claim 22 , wherein said threaded portions have reverse angle threads. 
     
     
         25 . The system of  claim 21 , wherein said anchoring member includes a hook member. 
     
     
         26 . The system of  claim 21 , wherein said offset member includes a rod receiving channel defined in said body for receiving said rod. 
     
     
         27 . The system of  claim 26 , wherein said offset member includes a threaded bore intersecting said rod receiving channel and a threaded set screw provided in said threaded bore. 
     
     
         28 . The system of  claim 26 , further comprising a slot defined in said rod receiving channel. 
     
     
         29 . The system of  claim 21 , wherein said body includes a pair of body members that define a channel in said body for receiving said rod. 
     
     
         30 . The system of  claim 29 , wherein said offset member has a longitudinal axis extending along said coupling member, and said body members extend parallel to said longitudinal axis. 
     
     
         31 . The system of  claim 29 , wherein said offset member has a longitudinal axis extending along said coupling member, and said body members extend perpendicular to said longitudinal axis. 
     
     
         32 . The system of  claim 29 , wherein one of said body members has a threaded bore defined therein and a threaded set screw provided in said threaded bore. 
     
     
         33 . The system of  claim 21 , further comprising a washer having a recessed portion adapted to accommodate said orthopedic rod and a radially extending projection, said washer being fitted within said saddle member. 
     
     
         34 . The system of  claim 33 , further comprising a snap ring provided in said saddle for securing said washer in said saddle member. 
     
     
         35 . The system of  claim 21 , further comprising said orthopedic rod coupled to said offset member. 
     
     
         36 . The system of  claim 35 , wherein said orthopedic rod includes an occipital rod. 
     
     
         37 . The system of  claim 35 , further comprising an occipital plate coupled to said rod, said plate including:
 a cross-shaped member having a longitudinal axis connecting first and second longitudinal ends and a transverse axis connecting first and second transverse ends, said cross-shaped member having a plurality of apertures therethrough; and   a plate saddle member coupled to said cross-shaped member, said plate saddle member having a plurality of upright portions that define a channel through said plate saddle member, wherein said rod is coupled in said channel.   
     
     
         38 . The system of  claim 37 , further comprising a cross-link connector having a pair of coupling ends each adapted to couple to a rod and a cylindrical member provided between said coupling ends, one of said coupling ends being coupled to said rod. 
     
     
         39 . An orthopedic fixation plate, comprising:
 a cross-shaped member having a longitudinal axis connecting first and second longitudinal ends and a transverse axis connecting first and second transverse ends, said cross-shaped member having a plurality of apertures therethrough; and   a saddle member coupled to said cross-shaped member, said saddle member having a plurality of upright portions that define a channel through said saddle member.   
     
     
         40 . The plate of  claim 39 , wherein said plate includes a plurality of saddle members attached to said cross-shaped member, each of said saddle members having a plurality of upright portions that define respective channels through said saddle members. 
     
     
         41 . The plate of  claim 39 , wherein said saddle member is integral with said cross-member. 
     
     
         42 . The plate of  claim 39 , wherein said saddle member is pivotally coupled to said cross-member. 
     
     
         43 . The plate of  claim 39 , wherein said saddle member is located at one of said first and second longitudinal ends. 
     
     
         44 . The plate of  claim 39 , wherein said channel of said saddle member has an axis, and said channel axis is substantially perpendicular to said longitudinal axis of said cross-shaped member. 
     
     
         45 . The plate of  claim 39 , wherein said cross-member has at least one of said apertures at each of said first and second transverse ends of said cross-member. 
     
     
         46 . The plate of  claim 39 , wherein said apertures are bounded by a surface having a conical portion. 
     
     
         47 . The plate of  claim 46 , wherein said surface has an upper conical portion and a lower conical portion. 
     
     
         48 . The plate of  claim 39 , wherein said cross-shaped member is curved. 
     
     
         49 . The plate of  claim 39 , wherein said cross-shaped member is curved so that said longitudinal axis has a curved portion and said transverse axis is substantially straight. 
     
     
         50 . A cross-link connector, comprising:
 a plurality of coupling ends each adapted to couple to an orthopedic rod; and   a cylindrical member integrally connected to said coupling ends, said cylindrical member having a cylindrical shape for permitting multi-axial bending of said cylindrical member.   
     
     
         51 . The cross-link connector of  claim 50 , wherein each of said coupling ends includes a curved member that defines a cavity adapted to receive said rod. 
     
     
         52 . The cross-link connector of  claim 51 , wherein each of said coupling ends includes a threaded bore and a set screw received in said bore for securing said rod. 
     
     
         53 . The cross-link connector of  claim 50 , wherein said cylindrical member is arched between said coupling ends. 
     
     
         54 . A multi-axial bone attachment assembly, comprising:
 a saddle member having a plurality of upright portions that define a channel through said saddle member, said saddle member further having a hole therethrough bounded by an inner wall, said hole forming a lower opening in said saddle member;   a bone anchoring member extending through said opening, said bone anchoring member including a coupling portion provided in said hole for permitting multi-axial movement of said anchoring member and an anchoring portion; and   an expansion member coupled to said anchoring member for expanding said coupling portion to lock said anchoring member into position.   
     
     
         55 . The assembly of  claim 54 , wherein said anchoring portion includes a hook member. 
     
     
         56 . The assembly of  claim 54 , wherein said coupling portion has a substantially spherical shape. 
     
     
         57 . The assembly of  claim 54 , wherein said coupling portion includes a plurality of part spherical members. 
     
     
         58 . The assembly of  claim 57 , wherein said expansion member is coupled to said anchoring member between said part spherical members. 
     
     
         59 . The assembly of  claim 54 , wherein said expansion member includes a set screw. 
     
     
         60 . The assembly of  claim 54 , wherein said expansion member includes a tool engaging portion, a threaded portion engaged with said coupling member, and a conically shaped expansion portion provided between said tool engaging portion and said threaded portion. 
     
     
         61 . The assembly of  claim 54 , wherein said upright portions include threaded portions, and said assembly further comprises a threaded member for engagement with said threaded portions. 
     
     
         62 . The assembly of  claim 61 , wherein said threaded portions have reverse angle threads.