Lordotic spinal implant

• US 6,120,506 A
• Filed: 07/29/1997
• Issued: 09/19/2000
• Est. Priority Date: 03/06/1997
• Status: Expired due to Term

• Current Assignee: Zimmer Spine, Inc. (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Sulzer Spine Tech, Inc.
• Inventors: Sand, Paul M., Kohrs, Douglas W.
• Primary Examiner(s): Yu, Mickey
• Assistant Examiner(s): STEWART, ALVIN J
• Application Number:
  US08/902,083
• Time in Patent Office: 1,148 Days
• Field of Search: 623/17, 623/16, 606/60, 606/61, 606/72, 606/73, 606/79, 606/80, 606/96, 606/53, 408/207, 408/219, 408/220, 408/222, 408/215, 408/72 R, 470/198
• US Class Current: 606/80
• CPC Class Codes: A61B 17/1671 for the spine
• 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 2/4611 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 2002/3021 frustoconical
• CPC Class Codes: A61F 2002/30217 hollow cones, e.g. tubular-like cones
• CPC Class Codes: A61F 2002/30593 hollow
• 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 2002/30797 internally-threaded
• CPC Class Codes: A61F 2002/30868 Square, rectangular or rhomboidal threads
• CPC Class Codes: A61F 2002/30873 Threadings machined on non-cylindrical external surfaces
• 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 2230/0067 conical
• CPC Class Codes: Y10S 606/916 Tool for installing or removing orthopedic fastener
• CPC Class Codes: Y10T 408/896 Having product-receiving chamber
• CPC Class Codes: Y10T 408/9046 including tapered section
• CPC Class Codes: Y10T 408/90467 and relieved cutting edge
• CPC Class Codes: Y10T 408/9048 : Extending outwardly from tool-axis

Abstract

A lordotic implant has a frusto-conical shape with external threads. Prior to placement of the implant, vertebrae are distracted in a manner to provide a desired lordosis between the vertebrae. The pre-distracted vertebrae are then tapped to provide a tapped bore having a geometry matching the conical geometry of the implant. The threaded implant is then placed within the pre-tapped conical bore.

Claims

1. A tap for preparing a site for placement of a spinal implant into a disk space between opposing vertebrae by forming a thread receiving groove in opposing surfaces of said vertebrae, said tap comprising:

a shaft defining a longitudinal axis;

a generally frusto-conical tapping head at a distal end of said shaft, said tapping head having a tapping thread surrounding said axis for tapping said thread receiving groove and generating a tapped debris as said tapping head is rotated about said axis;

said tapping head including a hollow body defining a tap interior;

said tapping thread including a plurality of peaks and valleys defining a conical tap thread pattern around said axis with a leading end having a leading end tap diameter adjacent said distal end and with a trailing end having a trailing end tap diameter spaced from said distal end, said trailing end tap diameter being greater than said leading end tap diameter;

a plurality of axially oriented channels, said channels passing through said tapping thread into said tap interior of said tapping head for directing said tapped debris from said tapping threads into said tap interior; and

a depth insertion indicator for indicating when a predetermined depth of insertion of said tap is obtained.

2. A tap according to claim 1 wherein said tapping head includes a guide on said distal end.

5. A tap according to claim 1 wherein said tapping thread has a sharp radial extremity.

3. A tap according to claim 6 wherein said guide is a cylindrical surface coaxially disposed on said leading end.

4. A tap according to claim 3 wherein said cylindrical surface has a diameter approximate said leading end tap diameter.