Two part intersomatic implant
View Patent ↗A spinal implant including a hollow body having a distal end, a proximal end, and a pair of lateral walls extending from the distal end to the proximal end, the lateral walls having concave, non-threaded interior surfaces for defining an at least partially cylindrical internal space between the lateral walls. The implant includes an anchoring member having bone anchoring projections including a screw thread on an exterior surface thereof, wherein the screw thread of the anchoring member is a self-tapping screw thread having a radial cross-section that transforms from a substantially triangular radial cross-section to a substantially square radial cross-section starting from a distal end of the thread, and wherein at least one of the lateral walls adjacent the proximal end of the hollow body includes a reentrant thread adapted to cooperate with the screw thread of the anchoring member when the anchoring element is rotated for enabling the anchoring member to be screwed into the internal space of the hollow body.
1. A spinal implant comprising:
a hollow body having a distal end, a proximal end, and a pair of lateral walls extending from said distal end to said proximal end, said lateral walls having concave, non-threaded interior surfaces for defining an at least partially cylindrical internal space between said lateral walls; and
an anchoring member having bone anchoring projections including a screw thread on an exterior surface thereof, wherein the screw thread of said anchoring member is a self-tapping screw thread having a radial cross-section that transforms from a beveled distal end to a substantially square radial cross-section, and wherein at least one of said lateral walls adjacent the proximal end of said hollow body includes a reentrant thread adapted to cooperate with the screw thread of said anchoring member when said anchoring element is rotated for enabling said anchoring member to be screwed into the internal space of said hollow body.
2. The implant as claimed in claim 1 , wherein said reentrant thread is provided on only one of said lateral walls.
3. The implant as claimed in claim 1 , wherein said reentrant thread is the only part of said hollow body that threadably engages the screw thread of said anchoring member.
4. The implant as claimed in claim 1 , wherein said reentrant thread includes a substantially rectilinear edge.
5. The implant as claimed in claim 1 , wherein the lateral walls of said hollow body define a height of said hollow body.
6. The implant as claimed in claim 5 , wherein the projections of said anchoring member have a diameter greater than the height of said hollow body.
7. The implant as claimed in claim 1 , wherein said hollow body has upper and lower faces that are inclined relative to one another so that a distance between the upper and lower faces decreases from the proximal end to the distal end of said hollow body.
8. The implant as claimed in claim 1 , wherein said hollow body has upper and lower faces that are inclined relative to one another, and wherein a distance between the upper and lower faces decreases from a first lateral side of said hollow body to a second lateral side of said hollow body opposite the first lateral side.
9. The implant as claimed in claim 8 , wherein said lateral walls have first openings for permitting bone in-growth through said lateral walls.
10. The implant as claimed in claim 9 , wherein the internal space of said hollow body is in communication with the first openings extending through said lateral walls.
11. The implant as claimed in claim 10 , wherein said lateral walls have second openings extending there through between the upper and lower faces of said hollow body.
12. The implant as claimed in claim 11 , wherein said second openings are in communication with said first openings.
13. The implant as claimed in claim 9 , wherein said first openings are in communication with outer sides of said hollow body.
14. The implant as claimed in claim 1 , wherein said hollow body has a distal end wall connecting said lateral walls, said distal end wall being rounded to facilitate insertion of said hollow body into an intervertebral space.
15. The implant as claimed in claim 1 , wherein said anchoring member has a proximal end, a distal end, a major axis extending between the proximal and distal ends, an interior space, and a fork surrounding the interior space, said fork including branches extending along a major axis of said anchoring member, said branches having a frustoconical exterior surface with a diameter that decreases from the proximal end toward the distal end of said anchoring member, and wherein the screw thread comprises a helical band connected to said fork and encircling said fork and the interior space of said anchoring member.
16. The implant as claimed in claim 1 , wherein said anchoring member is oriented obliquely relative to a sagittal plane of the spine.
17. The implant as claimed in claim 1 , wherein said anchoring member is oriented at approximately 45° relative to the sagittal plane of the spine.
18. The implant as claimed in claim 1 , wherein said implant includes a substantially cylindrical plug insertable into an end opening at the proximal end of said anchoring member for preventing reverse rotation of said anchoring member relative to said hollow body.
19. The implant as claimed in claim 18 , wherein a portion of the screw thread at the proximal end of said anchoring member is deformed, the deformed screw thread portion being engageable with said substantially cylindrical plug for preventing reverse rotation of said anchoring member.