Zimmer Biomet Spine Inc v. Jackson Roger P

1. Case Identification

• Case #: IPR2023-01433
• Patent #: 11,129,646
• Filed: September 22, 2023
• Petitioner(s): Zimvie, Inc. and Zimmer Biomet Spine, Inc.
• Patent Owner(s): Roger P. Jackson
• Challenged Claims: 1-20

2. Patent Overview

• Title: Medical Implant Threaded Plug Having a Start Structure with Symmetrically Shaped Concave and Convex Leading Surfaces
• Brief Description: The ’646 patent is directed to threaded closure plugs (setscrews) for use in spinal surgery. The plugs are designed to secure a spinal rod within the U-shaped receiver of a pedicle screw, featuring a specific thread start structure with a curvate leading face and a substantially flat bottom surface to engage the rod.

3. Grounds for Unpatentability

Ground 1: Claims 1-2 and 4-9 are anticipated or obvious over the ’477 Publication.

• Prior Art Relied Upon: ’477 Publication (Application # 2005/0267477).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that the ’477 Publication, which is in the same field of endeavor, discloses all limitations of independent claim 1. Specifically, it teaches a spinal implant closure with a truncated thread start having a curvate, s-shaped leading face that includes both partial concave and convex surfaces. Petitioner contended that the ’477 Publication also discloses a closure bottom that may be "substantially flat and have a lateral rim," which meets the "substantially flat bottom surface with an annular outer edge" limitation. Dependent claims reciting features like a tangential blend (claim 2), a partial planar surface (claim 4), a beveled surface (claim 5), and a reverse angle thread (claims 6-7) were also alleged to be disclosed.
  • Motivation to Combine (for §103 grounds): This ground was primarily asserted as anticipation, but Petitioner argued that to the extent any feature was not explicitly disclosed, it would have been an obvious modification. For example, selecting a reverse angle thread from known options as taught by the ’477 Publication would have been obvious.
  • Expectation of Success (for §103 grounds): A POSITA would have had a high expectation of success as the ’477 Publication teaches all the key features in a similar device for the same purpose.

Ground 2: Claims 3, 12-18, and 20 are obvious over the ’477 Publication in view of Boschert.

• Prior Art Relied Upon: ’477 Publication (Application # 2005/0267477) and Boschert (Patent 7,857,834).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground targets independent claim 12, which, unlike claim 1, explicitly requires a double-start thread ("a first thread and a second thread"). Petitioner argued that Boschert explicitly teaches the advantage of using a "double lead" thread on a closure screw to allow it "to start more easily than with a single lead." Boschert also discloses that the start structures for its double lead thread are symmetrically and diametrically opposed.
  • Motivation to Combine (for §103 grounds): A POSITA would combine the known, advantageous double-start thread from Boschert with the closure plug of the ’477 Publication. The motivation was to gain the known benefit of easier thread starting (from Boschert) while retaining the known benefits of the ’477 Publication’s curvate leading face, such as easier insertion and reduced thread deformation. This combination of predictable elements would address a known need in the art.
  • Expectation of Success (for §103 grounds): A POSITA would have reasonably expected success because combining multi-start threads with different thread forms were well-known techniques for achieving predictable improvements in mechanical performance.

Ground 3: Claims 3, 12-18, and 20 are obvious over the ’477 Publication in view of Boschert and Kirschman.

• Prior Art Relied Upon: ’477 Publication (Application # 2005/0267477), Boschert (Patent 7,857,834), and Kirschman (Application # 2011/0152947).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground adds Kirschman to the combination of Ground 2 to further reinforce the obviousness of specific limitations. Kirschman was cited for its clear disclosure of "locking aids" for closure plugs, including a flat bottom surface with a "deformable ring" to enhance fixation and an unthreaded, frusto-conical surface below the threads to facilitate alignment. Petitioner argued Kirschman’s teachings make the "substantially flat bottom surface" and the spacing between the thread start and the bottom surface even more explicit and obvious.
  • Motivation to Combine (for §103 grounds): A POSITA, when combining ’477 and Boschert, would have been motivated to look to other art like Kirschman to implement known, advantageous features for rod engagement and alignment. Kirschman’s express teachings on improving fixation and guiding the cap would have provided a strong reason to incorporate its bottom surface and unthreaded guide surface into the design.
  • Key Aspects: This ground emphasizes that the key features of the claims were not only known individually but were part of a finite number of predictable design solutions available to a POSITA.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including claims 1-2 and 4-9 over ’477 in view of Kirschman; claims 10-11 over ’477, Kirschman, and Johnson; and claim 19 over ’477, Boschert, Kirschman, and Johnson, which relied on similar motivations to combine known features for predictable results.

4. Key Claim Construction Positions

• "a substantially flat bottom surface with an annular outer edge" (Claims 1, 12): Petitioner proposed this term should be construed to mean a closure top with a planar bottom surface and a downwardly projecting rim, consistent with the patent’s figures and embodiments. Petitioner argued a POSITA would understand this from the specification, which contrasts this "rimmed" embodiment with a non-flat "domed" embodiment. An alternative construction proposed that the flat bottom surface of the rim itself could be the "substantially flat bottom surface."
• "an outward facing surface encircling the substantially flat bottom surface" (Claim 12): Petitioner contended this refers to the cylindrical side surface of the plug body, which faces outward and encircles the planar bottom surface. Under the alternative construction, it would refer to the outward-facing side surface of the projecting rim.

5. Arguments Regarding Discretionary Denial

• §325(d): Petitioner argued against denial, asserting that the core prior art and arguments were not previously presented to the USPTO. While Boschert was considered during prosecution, it was only for its disclosure of double-start threads. The examiner allegedly never considered the teachings of the primary reference, the ’477 Publication, or Kirschman with respect to the key limitations (flat bottom with annular edge, spacing) that were added via amendment to overcome the prior art and secure allowance. Petitioner characterized this as a material error by the examiner.
• Fintiv: To avoid discretionary denial under Fintiv, Petitioner stipulated that, if the IPR is instituted, it will not pursue in the parallel district court litigation any invalidity ground that was raised or could have reasonably been raised in the petition.

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-20 of the ’646 patent as unpatentable.