Bone fixation system

• US 6,342,055 B1
• Filed: 05/28/1999
• Issued: 01/29/2002
• Est. Priority Date: 04/29/1999
• Status: Expired due to Term

• Current Assignee: Theken Spine LLC (Orthofix Medical Inc.)
• Original Assignee: The Theken Surgical LLC
• Inventors: Eisermann, Lukas G., Theken, Randall R.
• Primary Examiner(s): Mancene, Gene
• Assistant Examiner(s): Priddy, Michael B.
• Application Number:
  US09/322,545
• Time in Patent Office: 977 Days
• Field of Search: 606/53, 606/60, 606/61, 606/69, 606/70, 606/73, 606/76
• US Class Current: 623/17.16
• CPC Class Codes: A61B 17/68 Internal fixation devices , including fasteners and spinal fixators, even if a part thereof projects from the skin bone staples A61B17/0642
• CPC Class Codes: A61B 17/7059 Cortical plates A61B17/7007, A61B17/7058 take precedence
• CPC Class Codes: A61B 17/8052 immobilised relative to screws by interlocking form of the heads and plate holes, e.g. conical or threaded
• CPC Class Codes: A61B 17/8605 Heads, i.e. proximal ends projecting from bone
• CPC Class Codes: A61B 17/863 with thread interrupted or changing its form along shank, other than constant taper
• CPC Class Codes: A61B 17/8886 holding the screw head
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• CPC Class Codes: A61F 2002/2817 Bone stimulation by chemical reactions or by osteogenic or biological products for enhancing ossification, e.g. by bone morphogenetic or morphogenic proteins [BMP] or by transforming growth factors [TGF]
• CPC Class Codes: A61F 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/30578 having apertures, e.g. for receiving fixation screws
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30785 parallel
• CPC Class Codes: A61F 2002/30787 inclined obliquely with respect to each other

Abstract

A novel apparatus for securing the head of a screw in a bone plate is disclosed in which bone fasteners or screws snap-fit into an undercut of fastener receiving openings of the bone plate. The bone fasteners or screws are designed such that they may be removed or repositioned from the snap-fit undercuts with the aid of a driver instrument. An embodiment is also disclosed in which a fusion cage is utilized in connection with bone plate and fasteners.

Claims

1. A bone fixation apparatus comprising:

a) a bone plate having a first end, a second end, a first edge extending from said first end to said second end, a second edge opposite said first edge and extending from said first end to said second end, a posterior surface for engaging a portion of the bone being fixated, an anterior surface, and at least one fastener receiving opening therethrough, said at least one fastener receiving opening including at least one undercut wherein said anterior surface of said bone plate has at least one stress controlling ridge substantially positioned in the longitudinal direction and not coincident with the neutral axis, and

b) at least one fastener having a head portion, said fastener being received and retained by said at least one fastener receiving opening with said head portion engaging said at least one undercut.

2. A bone fixture apparatus comprising:

a) a bone plate having a first end, a second end, a first edge extending from said first end to said second end, a second edge opposite said first edge and extending from said first end to said second end, a posterior surface for engaging a portion of the bone being fixated, an anterior surface, and at least one fastener receiving opening therethrough, said at least one fastener receiving opening including at least one undercut wherein said posterior surface of said bone plate has at least one stress controlling ridge substantially positioned in the longitudinal direction and not coincident with the neutral axis, and

b) at least one fastener having a head portion, said fastener being received and retained by said at least one fastener receiving opening with said head portion engaging said at least one undercut.

3. A bone fixation apparatus comprising:

a) a bone plate having a first end, a second end, a first edge extending from said first end to said second end, a second edge opposite said first edge and extending from said first end to said second end, a posterior surface for engaging a portion of the bone being fixated, an anterior surface, and at least one fastener receiving opening therethrough, said at least one fastener receiving opening having a protrusion section wherein said anterior surface of said bone plate has at least one stress controlling ridge positioned in the longitudinal direction and not coincident with the neutral axis; and

b) at least one fastener having a head portion, said head portion capable of mating with said protrusion of said fastener receiving opening.

4. A bone fixation apparatus comprising:

a) a bone plate having a first end, a second end, a first edge extending from said first end to said second end, a second edge opposite said first edge and extending from said first end to said second end, a posterior surface for engaging a portion of the bone being fixated, an anterior surface, and at least one fastener receiving opening therethrough, said at least one fastener receiving opening having a protrusion section wherein said posterior surface of said bone plate has at least one stress controlling ridge positioned in the longitudinal direction and not coincident with the neutral axis; and

b) at least one fastener having a head portion, said head portion capable of mating with said protrusion of said fastener receiving opening.

5. A bone fixation apparatus comprising:

a) a bone plate having a first end, a second end, a first edge extending from said first end to said second end, a second edge opposite said first edge and extending from said first end to said second end, a posterior surface for engaging a portion of the bone being fixated, an anterior surface, and a plurality of fastener receiving openings therethrough, said plurality of fastener receiving openings including an undercut therein wherein said anterior surface of said bone plate has at least one stress controlling ridge positioning in the longitudinal direction and not coincident with the neutral axis; and

b) a plurality of fasteners having a head portion, said plurality of fasteners being received and retained by said plurality of fastener receiving openings with said head portion engaging said undercut.

6. A bone fixation apparatus comprising:

a) a bone plate having a first end, a second end, a first edge extending from said first end to said second end, a second edge opposite said first edge and extending from said first end to said second end, a posterior surface for engaging a portion of the bone being fixated, an anterior surface, and a plurality of fastener receiving openings therethrough, said plurality of fastener receiving openings including an undercut therein wherein said posterior surface of said bone plate has at least one stress controlling ridge positioning in the longitudinal direction and not coincident with the neutral axis; and

b) a plurality of fasteners having a head portion, said plurality of fasteners being received and retained by said plurality of fastener receiving openings with said head portion engaging said undercut.

7. A bone fixation fusion cage apparatus comprising:

a.) a bone plate having a caudal end, a cephalad end, a posterior surface for engaging a bone to be fixated, an anterior surface, a plurality of fastener receiving openings therethrough;

b.) a plurality of fasteners capable of insertion into said plurality of fastener receiving openings; and

c.) a graft receiving area connected to said bone plate;

said graft receiving area having at least one vascular window therethrough wherein said graft receiving area further comprises a cephalad end plate angle.

8. The bone fixation fusion cage apparatus of claim 7 wherein said plurality of fastener receiving openings includes at least one caudal fastener receiving opening.

9. The bone fixation fusion cage apparatus of claim 7 wherein said plurality of fasteners includes at least one caudal fastener.

10. The bone fixation fusion cage apparatus of claim 9 wherein said at least one caudal fastener further comprises a head portion.

11. The bone fixation cage apparatus of claim 10 wherein said at least one caudal fastener receiving opening further comprises an undercut portion therein for engaging said head portion of said at least one caudal fastener.

12. The bone fixation fusion cage apparatus of claim 7 wherein said plurality of fastener receiving openings includes at least one cephalad fastener receiving opening.

13. The bone fixation fusion cage apparatus of claim 7 wherein said plurality of fasteners includes at least one cephalad fastener.

14. The bone fixation fusion cage apparatus of claim 13 wherein said at least one cephalad fastener further comprises a head portion.

15. The bone fixation cage of claim 14 wherein said at least one cephalad fastener receiving opening further comprises an undercut portion therein for engaging said head portion of said at least one cephalad fastener.

16. A bone fixation fusion cage apparatus comprising:

a.) a bone plate having a caudal end, a cephalad end, a posterior surface for engaging a bone to be fixated, an anterior surface, a plurality of fastener receiving openings therethrough;

b.) a plurality of fasteners capable of insertion into said plurality of fastener receiving openings; and

c.) a graft receiving area connected to said bone plate;

said graft receiving area having at least one vascular window therethrough wherein said graft receiving area further comprises a caudal end plate angle.

17. The bone fixation fusion cage apparatus of claim 16 wherein said plurality of fastener receiver openings includes at least one caudal fastener receiver opening.

18. The bone fixation fusion cage apparatus of claim 16 wherein said plurality of fasteners includes at least one caudal fastener.

19. The bone fixation fusion cage apparatus of claim 18 wherein said at least one caudal fastener further comprises a head portion.

20. The bone fixation cage apparatus of claim 19 wherein said at least one caudal fastener receiving opening further comprises an undercut portion therein for engaging said head portion of said at least one caudal fastener.

21. The bone fixation fusion cage apparatus of claim 16 wherein said plurality of fastener receiving openings includes at least one cephalad fastener receiving opening.

22. The bone fixation fusion cage apparatus of claim 16 wherein said plurality of fasteners includes at least one cephalad fastener.

23. The bone fixation fusion cage apparatus of claim 22 wherein said at least one cephalad fastener further comprises a head portion.

24. The bone fixation cage of claim 23 wherein said at least one cephalad fastener receiving opening further comprises an undercut portion therein for engaging said head portion of said at least one cephalad fastener.