Medacta USA Inc v. RSB Spine LLC

1. Case Identification

• Case #: IPR2020-00264
• Patent #: 9,713,537
• Filed: December 13, 2019
• Petitioner(s): Medacta USA, Inc., Precision Spine, Inc., and Life Spine, Inc.
• Patent Owner(s): RSB Spine, LLC
• Challenged Claims: 1, 3-6, 10, 13-15, 18, 19, 21, 22, 24, 29, and 30

2. Patent Overview

• Title: Implant Devices for the Fixation and Support of Bone Bodies
• Brief Description: The ’537 patent discloses a bone stabilization plate system for spinal fusion. The system features a base plate designed to fit between adjacent vertebral bodies, specifically between their lip osteophytes, to hold bone graft material and bear weight while promoting fusion.

3. Grounds for Unpatentability

Ground 1: Obviousness over Fraser - Claims 1, 10, 13-14, 21-22, and 29 are obvious over Fraser.

• Prior Art Relied Upon: Fraser (Patent 6,432,106).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Fraser’s fused implant embodiment, which includes a spinal fixation assembly with a fusion cage and a mated plate, discloses all limitations of independent claim 1. Fraser’s plate is configured to fit between vertebral bodies, hold them in a stable relationship, and bear weight. It includes screw holes that extend from its top surface and open toward the side surfaces of the vertebral bones and their corners (lip osteophytes), with screws oriented in an anterior-posterior direction, as required by claim 1. Dependent claims were mapped to features like Fraser’s lateral tabs (claim 10) and its flush-fitting design (claim 13).
  • Motivation to Combine (for §103 grounds): This ground relies on a single reference, arguing that Fraser itself renders the claims obvious. Petitioner contended that it would have been obvious for a person of ordinary skill in the art (POSITA) to use the Fraser device as disclosed.
  • Expectation of Success (for §103 grounds): A POSITA would have had a high expectation of success as Fraser explicitly teaches a stable, load-bearing spinal fusion device.

Ground 2: Obviousness over Fraser in view of Byrd - Claims 3, 15, and 19 are obvious over Fraser in view of Byrd.

• Prior Art Relied Upon: Fraser (Patent 6,432,106) and Byrd (Patent 7,077,864).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground built upon the teachings of Fraser by adding Byrd to teach the limitation of a "generally flat bottom surface" (claim 3). Petitioner asserted that while Fraser’s implant has transverse elements on its bottom surface, these are optional. Byrd explicitly discloses a spinal cage with a "substantially ‘flat’ or smoothly, fluidly continuous" surface that contacts bone graft material. Modifying Fraser’s bottom surface to be flat as taught by Byrd would have been an obvious design choice. This combination was also argued to render independent claim 15 obvious, which recites similar features to claim 1 but adds limitations like not covering significant portions of the bone's top surfaces, a feature inherent in Fraser's interbody design.
  • Motivation to Combine (for §103 grounds): A POSITA would combine Fraser and Byrd because both are analogous art directed to spinal fusion implants that retain bone graft material. Petitioner argued a POSITA would be motivated to modify Fraser to incorporate Byrd's flat bottom surface to create a simpler, less expensive device that promotes bone growth across an open interior, which is an improvement over Fraser’s ribbed design.
  • Expectation of Success (for §103 grounds): The proposed modification was a simple removal of optional elements from Fraser to achieve the known benefits of a flat surface as shown in Byrd, leading to a predictable result.

Ground 3: Obviousness over Fraser in view of Michelson - Claims 4-6, 24, and 30 are obvious over Fraser in view of Michelson.

• Prior Art Relied Upon: Fraser (Patent 6,432,106) and Michelson (International Publication No. WO 2000/066045A1).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground added Michelson to Fraser to teach the "screw retainer" limitations of claims 4-6, 24, and 30. Fraser does not explicitly disclose a separate screw retainer. Michelson teaches an anti-back-out locking mechanism (lock 461) with a head and threaded shaft that engages bone screws to prevent them from backing out. Petitioner argued this lock constitutes the claimed "screw retainer," which can be a plate or screw (claim 5). Michelson also discloses configuring the implant with a recessed region to house the lock (claim 6), a feature that could be incorporated into Fraser's design.
  • Motivation to Combine (for §103 grounds): A POSITA would combine Fraser and Michelson to improve the safety and reliability of the Fraser implant. Both are analogous art addressing spinal fusion. Petitioner argued that incorporating a known anti-back-out mechanism like Michelson’s into Fraser’s system would be a simple substitution of one known element (Fraser’s screw-head geometry) for another (Michelson’s locking plate) to solve the known problem of screw back-out.
  • Expectation of Success (for §103 grounds): Anti-back-out plates were well-known and easy to implement, so a POSITA would have a high expectation of success in combining these known elements for their intended and predictable function.
• Additional Grounds: Petitioner asserted an additional obviousness challenge against claim 18 based on a three-way combination of Fraser, Michelson, and Byrd. An alternative ground was also presented based on a two-piece embodiment of Fraser in view of POSITA knowledge.

4. Key Claim Construction Positions

• "base plate": Petitioners proposed a construction of "A fixation plate...that is not used with a load-bearing fusion cage," arguing that the Patent Owner disclaimed two-piece plate/cage systems during prosecution to overcome a rejection based on the Fraser ’222 patent. Patent Owner proposed a construction that the base plate is "distinct from a spacer," which Petitioners argued improperly excluded preferred embodiments of the ’537 patent that show an integrated spacer.
• "lip osteophyte": Petitioners argued the term should be construed as a "bony outgrowth at the anterior corner of the bone," which is consistent with medical understanding of how osteophytes form on degraded spinal discs. Patent Owner’s proposed construction did not include the "bony outgrowth" limitation.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under 35 U.S.C. §325(d) was inappropriate because the primary prior art references, Fraser ’106 and Michelson ’045, were materially different from the art considered during prosecution. The examiner previously considered art where screws entered the anterior surface of the vertebrae, whereas Fraser and Michelson, like the ’537 patent, disclose screws entering the side surfaces and lip osteophytes. Therefore, the asserted references were not cumulative and raised new issues of patentability that the examiner did not previously consider.

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1, 3-6, 10, 13-15, 18, 19, 21, 22, 24, 29, and 30 of the ’537 patent as unpatentable.