Methods and instruments for interbody fusion

• US 6,471,724 B2
• Filed: 02/05/2001
• Issued: 10/29/2002
• Est. Priority Date: 03/27/1995
• Status: Expired due to Fees

• Current Assignee: SDGI Holdings Incorporated (Medtronic Plc)
• Original Assignee: SDGI Holdings Incorporated (Medtronic Plc)
• Inventors: Zdeblick, Thomas, McGahan, Thomas
• Primary Examiner(s): McDermott, Corrine
• Assistant Examiner(s): STEWART, ALVIN J
• Application Number:
  US09/781,589
• Publication Number:
  US 20010005796A1
• Time in Patent Office: 631 Days
• Field of Search: 623/17.11, 623/17.15, 623/17.16
• US Class Current: 623/17.16
• CPC Class Codes: A61B 1/3132 for laparoscopy
• CPC Class Codes: A61B 1/3135 for examination of the epidural or the spinal space
• CPC Class Codes: A61B 17/025 Joint distractors
• CPC Class Codes: A61B 17/1671 for the spine
• CPC Class Codes: A61B 17/1757 for the spine
• CPC Class Codes: A61B 17/282 Jaws
• CPC Class Codes: A61B 17/7059 Cortical plates A61B17/7007, A61B17/7058 take precedence
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61B 2017/00238 Type of minimally invasive operation A61B2017/00805 takes precedence
• CPC Class Codes: A61B 2017/00261 Discectomy
• CPC Class Codes: A61B 2017/0256 for the spine
• CPC Class Codes: A61B 2017/3488 Fixation to inner organ or inner body tissue
• CPC Class Codes: A61B 2090/3904 specially adapted for marking specified tissue
• CPC Class Codes: A61B 2090/3937 Visible markers
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/446 having a circular or elliptical cross-section substantially parallel to the axis of the spine, e.g. cylinders or frustocones
• CPC Class Codes: A61F 2/4601 for introducing bone substitute, for implanting bone graft implants or for compacting them in the bone cavity
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• 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 2002/2839 Bone plugs or bone graft dowels
• CPC Class Codes: A61F 2002/30123 : with two diametrically opposed lobes
• CPC Class Codes: A61F 2002/30153 : rectangular
• CPC Class Codes: A61F 2002/30179 : X-shaped
• CPC Class Codes: A61F 2002/3021 : frustoconical
• CPC Class Codes: A61F 2002/30217 : hollow cones, e.g. tubular-like cones
• CPC Class Codes: A61F 2002/30329 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2002/30433 : using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30507 : using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30593 : hollow
• CPC Class Codes: A61F 2002/30604 : modular
• CPC Class Codes: A61F 2002/30774 : internally-threaded
• CPC Class Codes: A61F 2002/30777 : Oblong apertures
• CPC Class Codes: A61F 2002/30785 : parallel
• CPC Class Codes: A61F 2002/30787 : inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30789 : perpendicular with respect to each other
• CPC Class Codes: A61F 2002/3082 : Grooves
• CPC Class Codes: A61F 2002/30858 : Threads interrupted by grooves or sidewalls, e.g. flat sidewalls
• CPC Class Codes: A61F 2002/30863 : the entry end surface having flutes, relief grooves, starter notches or bevelled indentations
• CPC Class Codes: A61F 2002/30871 : Trapezoidal threads
• CPC Class Codes: A61F 2002/30873 : Threadings machined on non-cylindrical external surfaces
• 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 2002/4627 : with linear motion along or rotating motion about the instrument axis or the implantation direction, e.g. telescopic, along a guiding rod, screwing inside the instrument
• CPC Class Codes: A61F 2002/4635 : using minimally invasive surgery
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0041 : using additional screws, bolts, dowels or rivets, e.g. connecting screws
• CPC Class Codes: A61F 2230/0006 : circular
• CPC Class Codes: A61F 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0058 : X-shaped
• CPC Class Codes: A61F 2230/0067 : conical

Abstract

A laparoscopic surgical technique is provided for preparing a site for implantation of a novel fusion device or implant. In accordance with one embodiment of the technique, a laparoscope is provided having an outer sleeve with distraction fingers at one end to distract the disc space. The laparoscope provides a sealed working channel to the disc space, through which the disc space is distracted, the vertebral endplates and surrounding disc is reamed, and the fusion device inserted. A distraction plug is provided for centering the outer sleeve and for providing midline distraction of the disc space. In one embodiment, a fusion device includes diverging bone screws passing through an end wall and upper and lower walls of the device to engage the adjacent vertebrae. In another embodiment, a connector plate is engaged to bilaterally position fusion devices to prevent rotation and resist expulsion of the devices from the disc space.

Claims

1. An interbody fusion apparatus for implantation in the disc space between adjacent vertebrae to be fused, comprising:

a hollow body having at least an upper substantially cylindrical portion and a lower substantially cylindrical portion defining an outer diameter greater than the height of the disc space between the adjacent vertebrae, said substantially cylindrical portions each configured to contact a portion of one of the adjacent vertebrae, said body having a first end and an opposite second end and including an end wall at said first end, said end wall defining an upper portion and a lower portion;

a first screw bore defined through said end wall upper portion, said first screw bore defining a first longitudinal axis oriented such that said first longitudinal axis intersects said upper substantially cylindrical portion and a second screw bore defined through said end wall lower portion, said second screw bore defining a second longitudinal axis oriented such that said second longitudinal axis intersects said lower substantially cylindrical portion, the longitudinal axis of said first and second screw bores diverging from each other toward said second end; and

a first bone screw sized to extend through said first screw bore and project outward from said upper substantially cylindrical portion through a first aperture and a second bone screw sized to extend through said second screw bore and project outward from said lower substantially cylindrical portion through a second aperture disposed generally opposite said first aperture, said bone screws configured to threadedly engage the adjacent vertebrae to retain said hollow body within the disc space.

2. The interbody fusion apparatus according to claim 1, wherein:

said hollow body defines a longitudinal axis and a midline extending between said upper and lower substantially cylindrical portions, said midline intersecting said longitudinal axis, and said upper screw bore and said lower screw bore are disposed along said midline.

3. The interbody fusion apparatus according to claim 1, wherein

each of said two screw bores includes an enlarged recess at said end wall;

and

each of said two bone screws includes an enlarged head sized to be received within said enlarged recess.

4. The interbody fusion apparatus according to claim 1, wherein said at least two substantially cylindrical portions of said hollow body include external threads configured for threaded engagement with said adjacent vertebrae.

5. The interbody fusion apparatus according to claim 1, wherein said hollow body is tapered from said first end to said second end.

6. The interbody fusion apparatus according to claim 1, wherein said hollow body defines two opposite substantially flat walls between said at least two substantially cylindrical portions.

7. The interbody fusion apparatus according to claim 1, wherein said hollow body defines at least one slot extending through said hollow body and intersecting at least one of said substantially cylindrical portions.

8. The interbody fusion apparatus according to claim 7, wherein one of said screw bores intersects said at least one slot.

9. The interbody fusion apparatus according to claim 1, wherein:

said hollow body defines a longitudinal axis and a midline extending between said upper and lower substantially cylindrical portions, said midline intersecting said longitudinal axis, and said upper screw bore and said lower screw bore are disposed along said midline; and

further wherein said end wall defines a pair of elongated slots offset from and substantially parallel to said midline of said end wall.-

10. An interbody fusion apparatus for implantation in the disc space between adjacent vertebrae to be fused, comprising:

a hollow body having at least an upper substantially cylindrical portion and a lower substantially cylindrical portion defining an outer diameter greater than the height of the disc space between the adjacent vertebrae, said substantially cylindrical portions each configured to contact a portion of one of the adjacent vertebrae, said body having a first end and an opposite second end and including an end wall at said first end, said end wall defining an upper portion and a lower portion;

a first screw bore defined through said end wall upper portion, said first screw bore defining a first longitudinal axis oriented such that said first longitudinal axis intersects said upper substantially cylindrical portion and a second screw bore defined through said end wall lower portion, said second screw bore defining a second longitudinal axis oriented such that said second longitudinal axis intersects said lower substantially cylindrical portion, the longitudinal axis of said first and second screw bores diverging from each other toward said second end; and

a first bone screw sized to extend through said first screw bore and project outward from said upper substantially cylindrical portion through a first aperture and a second bone screw sized to extend through said second screw bore and project outward from said lower substantially cylindrical portion through a second aperture, said bone screws configured to threadedly engage the adjacent vertebrae to retain said hollow body within the disc space;

wherein said end wall of said hollow body defines a threaded bore between said two screw bores; and

wherein said apparatus includes a locking screw configured for engagement within said threaded bore, said locking screw having a head sized to contact each of said two bone screws when said bone screws are extended through a respective one of said two screw bores and when said locking screw is engaged in said threaded

11. The interbody fusion apparatus according to claim 10, wherein

each of said two screw bores includes an enlarged recess at said end wall;

each of said two bone screws includes an enlarged head sized to be received within said enlarged recess; and

said threaded bore includes an enlarged recess sized to receive said enlarged head of said locking screw therein, said enlarged recess of said threaded bore overlapping said enlarged recess of each of said bone screw bores.

12. An interbody fusion apparatus for implantation in the disc space between adjacent vertebrae to be fused, comprising:

a hollow body having an upper substantially cylindrical portion defining a first aperture and a lower substantially cylindrical portion defining a second aperture disposed generally opposite said first aperture, said body having an end wall defining an upper portion and a lower portion;

a first screw bore defined through said end wall upper portion;

a second screw bore defined through said end wall lower portion;

a first bone screw extending through said first screw bore and said first aperture and into threading engagement with one of said adjacent vertebrae; and

a second bone screw extending through said second screw bore and said second aperture and into threading engagement with an opposite one of said adjacent vertebrae.

13. The interbody fusion apparatus according to claim 12, wherein said end wall defines a midline extending between said upper and lower portions, said upper and lower screw bores disposed along said midline.

14. The interbody fusion apparatus according to claim 13, wherein said hollow body extends along a longitudinal axis, said midline intersecting said longitudinal axis.

15. The interbody fusion apparatus according to claim 12, wherein said upper and lower substantially cylindrical portions define an outer diameter greater than the height of the disc space between the adjacent vertebrae.

16. The interbody fusion apparatus according to claim 12, wherein

said end wall of said hollow body defines a threaded bore between said first and second screw bores; and

wherein the interbody fusion apparatus further comprises a locking screw configured for threading engagement with said threaded bore and into contact with each of said first and second bone screws.

17. The interbody fusion apparatus according to claim 12, wherein said upper and lower substantially cylindrical portions include external threads configured for threading engagement with said adjacent vertebrae.

18. The interbody fusion apparatus according to claim 12, wherein said hollow body defines two substantially fiat walls arranged generally opposite one another and extending between said upper and lower substantially cylindrical portions.