PTAB

IPR2020-00274

Medacta USA Inc v. RSB Spine LLC

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1. Case Identification

2. Patent Overview

  • Title: Interbody Bone Plate System
  • Brief Description: The ’234 patent is directed to a bone plate system for assisting in the surgical fusion of two bones, particularly vertebral bodies. The system features a bone plate designed to provide and control limited movement between the bones during the fusion process.

3. Grounds for Unpatentability

Ground 1: Obviousness over Michelson - Claims 1-10, 13-14, 16, 18-20, 22, 24-25, 28-29, and 31-32 are obvious over Michelson.

  • Prior Art Relied Upon: Michelson (International Publication No. WO 2000/066045A1).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Michelson discloses all limitations of the challenged claims. Independent method claim 1 and system claim 22 recite a "base plate" inserted between bones, having ends with screw holes angled relative to the plate's surface, and a means to prevent screw back-out. Petitioner asserted that Michelson’s integrated spinal fusion implant (implant 400) is a "base plate" under the proper construction, as it is a single component that stabilizes vertebrae for fusion without a separate load-bearing cage. Michelson's implant is inserted between vertebral bodies, has screw holes (430) at its ends angled between 15° and 65° relative to the bone surface (which overlaps the claimed ranges), and includes a locking mechanism (lock 462) to prevent screw back-out. Petitioner contended that Michelson similarly teaches the limitations of the dependent claims, including screw placement into the lip osteophyte (the structurally strongest part of the vertebral corner) and the inclusion of a third screw.
    • Key Aspects: Petitioner argued that even if the Board narrowly construes the "first and second ends" of the base plate to be only the corners, it would have been obvious to a Person of Ordinary Skill in the Art (POSITA) to modify Michelson’s implant by moving the screw holes to the upper and lower edges. This modification is taught by alternative embodiments within Michelson itself (e.g., implant 600), which demonstrates its feasibility and predictability.

Ground 2: Obviousness over Michelson in view of Fraser - Claims 2-8 and 16 are obvious over Michelson in view of Fraser.

  • Prior Art Relied Upon: Michelson (WO 2000/066045A1) and Fraser (Patent 6,432,106).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground supplements Ground 1 for specific dependent claims. Petitioner asserted that Michelson teaches the foundational interbody implant, while Fraser provides the express teaching for limitations not explicitly detailed in Michelson. Specifically, dependent claims 2, 3, and 4 require introducing screws "at a corner of the bone." Petitioner argued that Fraser explicitly discloses this feature, teaching bone screws (46, 48) that are introduced at a corner formed between the top and side surfaces of the vertebral body. Combining Fraser's corner-screw placement with Michelson's integrated implant design would render these claims obvious.
    • Motivation to Combine: Petitioner asserted three primary motivations for a POSITA to combine the references. First, the references are analogous art, as both disclose spinal implant devices for vertebral fixation and address the same problems of preventing screw back-out and avoiding damage to adjacent tissue. Second, Michelson provides an express motivation by teaching that its implant designs could be adapted for use in other spinal devices, prompting a POSITA to look to references like Fraser. Third, a POSITA would recognize that combining Fraser’s teachings on screw placement with Michelson’s implant would yield a predictably improved device with a greater range of screw insertion angles, a significant surgical advantage.
    • Expectation of Success: Petitioner argued a POSITA would have a reasonable expectation of success because the combination would only require modifying the location of drilled screw holes in the Michelson device, a straightforward and predictable engineering task.

4. Key Claim Construction Positions

  • "base plate":
    • Petitioner argued the term means a fixation plate distinct from bone graft material and, critically, "is not used with a load-bearing fusion cage." This construction is based on a clear and unambiguous disclaimer made by the Patent Owner during prosecution to overcome a rejection based on the Fraser ’222 patent, which disclosed a two-piece plate and fusion cage system. Petitioner also contended the Patent Owner’s proposed construction, which distinguishes the plate from "a spacer," is incorrect because the ’234 patent’s own preferred embodiment (Fig. 2) shows a base plate with an integrated spacer (60).
  • "lip osteophyte" / "lip osteophite":
    • Petitioner proposed the term means a "bony outgrowth at the anterior corner of the bone" that is also the structurally strongest portion. The key dispute is the "bony outgrowth" element, which Petitioner contended refers to a pathological formation resulting from disc degeneration, as opposed to the Patent Owner’s position that it is simply the normal lip of the vertebral body.
  • "bone screw retaining means" (Claim 22):
    • The parties agreed this is a means-plus-function term under §112, ¶ 6 with a function of "securedly covering" screws to prevent back-out. The dispute centered on the corresponding structure. Petitioner argued the structure is limited to the disclosed embodiments: "A single retaining plate and set screw, multiple retaining plates with set screws... or one or more screws with heads that overlap." The dispute is whether the structure includes "equivalents thereof," which Petitioner argued is improper to add to the construction itself.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-10, 13-14, 16, 18-20, 22, 24-25, 28-29, and 31-32 of the ’234 patent as unpatentable.