ZERO-PROFILE INTERBODY SPACER AND COUPLED PLATE ASSEMBLY

• US 20100145459A1
• Filed: 11/06/2009
• Published: 06/10/2010
• Est. Priority Date: 11/07/2008
• Status: Active Grant

• Current Assignee: Depuy Synthes Products Incorporated (Johnson & Johnson)
• Original Assignee: Depuy Synthes Products Incorporated (Johnson & Johnson)
• Inventors: Ponzer, Rainer, Koch, David, Richter, Joern, Berger, Roger, Bonner, Christopher, Meili, Ralph, Jeger, Michael, Pepe, Thomas, Kueenzi, Thomas, Hunziker, Markus, McDonough, William P., Strausbaugh, William L.
• Granted Patent: US 9,192,419 B2
• Time in Patent Office: Days
• US Class Current: 623/17.160
• CPC Class Codes: A61B 17/1728 for holes for bone plates or plate screws
• CPC Class Codes: A61B 17/1757 for the spine
• CPC Class Codes: A61B 17/7059 Cortical plates A61B17/7007, A61B17/7058 take precedence
• CPC Class Codes: A61B 17/8033 having indirect contact with screw heads, or having contact with screw heads maintained with the aid of additional components, e.g. nuts, wedges or head covers
• CPC Class Codes: A61B 17/8042 the additional component being a cover over the screw head
• 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 17/8057 the interlocking form comprising a thread
• CPC Class Codes: A61B 17/809 with bone-penetrating elements, e.g. blades or prongs bone staples A61B17/0642; intramedullary nails with a plate at an end A61B17/7233
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61B 17/88 Osteosynthesis instruments; Methods or means for implanting or extracting internal or external fixation devices A61B17/7074 takes precedence
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/4455 for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages intervertebral discs A61F2/442
• CPC Class Codes: A61F 2/4465 having a circular or kidney shaped cross-section substantially perpendicular to the axis of the spine
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/30387 Dovetail connection
• CPC Class Codes: A61F 2002/305 Snap connection
• CPC Class Codes: A61F 2002/30505 spring biased
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30517 using a locking plate
• CPC Class Codes: A61F 2002/30576 with extending fixation tabs
• CPC Class Codes: A61F 2002/30593 : hollow
• CPC Class Codes: A61F 2002/30604 : modular
• CPC Class Codes: A61F 2002/30787 : inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/3079 : Stepped or enlarged apertures, e.g. having discrete diameter changes
• CPC Class Codes: A61F 2002/30841 : Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/448 : comprising multiple adjacent spinal implants within the same intervertebral space or within the same vertebra, e.g. comprising two adjacent spinal implants
• CPC Class Codes: A61F 2002/4615 : of spacers
• CPC Class Codes: A61F 2220/0016 : with sharp anchoring protrusions, e.g. barbs, pins, spikes
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2230/0034 : D-shaped
• CPC Class Codes: A61F 2310/00017 : Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00029 : Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00131 : Tantalum or Ta-based alloys
• CPC Class Codes: A61F 2310/00407 : Coating made of titanium or of Ti-based alloys
• CPC Class Codes: A61F 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite

Abstract

An implant for insertion into a disc space between vertebrae, wherein the implant includes a spacer portion, a plate portion coupled to the spacer portion, two bone fixation elements for engaging the vertebrae and a retention mechanism for preventing the bone fixation elements from postoperatively backing-out of the plate portion. The retention mechanism may be in the form of a spring biased snapper element that is biased into communication with the bone fixation elements so that once the bone fixation element advances past the snapper element, the snapper element is biased back to its initial position in which the snapper element interfaces with the bone fixation elements. Alternatively, the retention mechanism may be in the form of a propeller rotatable between a first position in which the bone fixation elements are insertable to a second position where the bone fixation elements are prevented from backing-out.

Claims

1. An implant for insertion into an intervertebral disc space between superior and inferior vertebral bodies, the implant comprising:

first and second bone fixation elements;

a spacer portion including a top surface for contacting the superior vertebral body, a bottom surface for contacting the inferior vertebral body, a first side surface, a second side surface, a leading surface and a trailing surface;

a plate portion coupled to the spacer portion, the plate portion including a top surface, a bottom surface, a first side surface, a second side surface, a leading surface and a trailing surface, the plate portion further including first and second bone fixation holes and first and second boreholes, the first and second bone fixation holes sized and adapted for receiving the first and second bone fixation elements, respectively, the first bone fixation hole being angled so that the first bone fixation element engages the superior vertebral body, the second bone fixation hole being angled so that the second bone fixation element engages the inferior vertebral body, the first borehole being in communication with the first bone fixation hole, the second borehole being in communication with the second bone fixation hole; and

first and second spring-biased snapper elements for preventing the first and second bone fixation elements, respectively, from backing-out, the first spring biased snapper element being located in the first borehole, the second spring biased snapper elements being located in the second borehole, the first and second spring biased snapper elements being moveable from a first position to a second position, in the first position, at least a portion of the first and second snapper elements protrude into the first and second bone fixation holes, respectively, so that once the first and second bone fixation elements are inserted into the first and second bone fixation holes, respectively, the first and second snapper elements at least partially cover the first and second bone fixation elements, respectively, to prevent backing-out, the first and second spring biased snapper elements being biased to the first position.

2. The implant of claim 1, wherein a height of the plate portion is substantially equal to a height of the spacer portion and a width of the plate portion is substantially equal to a width of the spacer portion.

3. The implant of claim 1, wherein the spacer portion includes first and second recesses formed in the first and second side surfaces thereof, respectively, for engaging first and second projections extending from the plate portion.

4. The implant of claim 1, wherein each of the first and second spring biased snapper elements includes a spring and a snapper element, the snapper element including a tapered first end that protrudes into the first and second bone fixation holes for interacting with the first and second bone fixation elements, respectively, and a second end for interacting with the spring.

5. The implant of claim 4, wherein the first and second spring biased snapper elements are secured within the first and second boreholes, respectively, via first and second pins, respectively.

6. The implant of claim 1, wherein insertion of the first and second bone fixation elements causes the first and second spring biased snapper elements to move from their respective first position to their respective second positions.

7. The implant of claim 1, wherein insertion of the first and second bone fixation elements causes a head portion of the first and second bone fixation elements to contact the first and second spring biased snapper elements, respectively, to cause the first and second spring biased snapper elements to recoil from their first positions to the their second positions.

8. The implant of claim 7, wherein further insertion of the first and second bone fixation elements causes the head portions of the first and second bone fixation elements to move distally of the first and second spring biased snapper elements resulting in the first and second snapper elements automatically moving from their second position to their first positions.

9. The implant of claim 1, further comprising first and second stops to prevent over-insertion of the implant during implantation and to assist in securing a position of the implant during insertion of the first and second bone fixation elements, the first stop extending superiorly of the top surface of the plate portion for contacting the superior vertebral body, the second stop extending inferiorly of the bottom surface of the plate portion for contacting the inferior vertebral body.

10. The implant of claim 9, wherein the first and second stops are integrally formed with the plate portion.

11. An implant for insertion into an intervertebral disc space between superior and inferior vertebral bodies, the implant comprising:

first and second bone fixation elements;

a spacer portion including a top surface for contacting the superior vertebral body, a bottom surface for contacting the inferior vertebral body, a first side surface, a second side surface, a leading surface and a trailing surface;

a plate portion coupled to the spacer portion, the plate portion including a top surface, a bottom surface, a first side surface, a second side surface, a leading surface, a trailing surface, and first and second bone fixation holes, the first and second bone fixation holes sized and adapted for receiving the first and second bone fixation elements, respectively, the first bone fixation hole being angled so that the first bone fixation element engages the superior vertebral body, the second bone fixation hole being angled so that the second bone fixation element engages the inferior vertebral body;

a propeller element having a longitudinal axis extending between a first end and a second end, the propeller element coupled to the plate portion in-between the first and second bone fixation holes, the propeller rotatable between a first position wherein the propeller does not interfere with first and second bone fixation holes so that the first and second bone fixation elements can be inserted into the first and second bone fixation holes, respectively, to a second position wherein the first end of the propeller at least partially covers at least a portion of the first bone fixation hole and the second end of the propeller at least partially covers at least a portion of the second bone fixation hole to prevent backing-out of the first and second bone fixation elements once implanted.

12. The implant of claim 11, wherein the propeller is rotated through a range of about ninety degrees (90°

) from the first position to the second position.

13. The implant of claim 11, wherein the propeller includes a threaded screw for engaging a threaded borehole formed in the plate portion.

14. The implant of claim 11, wherein, in the first position, the longitudinal axis of the propeller is oriented generally parallel to an axis of the implant so that the first end of the propeller extends superiorly of the top surface of the plate portion and the second end of the propeller extends inferiorly of the bottom surface of the plate portion so that the propeller act as a stop during implantation of the implant to prevent over-insertion of the implant and to assist in securing a position of the implant during insertion of the first and second bone fixation elements.

15. The implant of claim 11, wherein the trailing surface of the plate portion includes tapered recesses that form guide ramps for the first and second ends of the propeller as the propeller is being rotated from the first position to the second position and so that in the second position, the propeller lies flush with the trailing surface of the plate portion.