NuVasive Inc v. Acantha LLC

1. Case Identification

• Case #: IPR2020-00684
• Patent #: RE43,008 E
• Filed: March 13, 2020
• Petitioner(s): NuVasive, Inc.
• Patent Owner(s): Acantha LLC
• Challenged Claims: 1-5, 10-19, 21-22, 29-32, 36-37

2. Patent Overview

• Title: Orthopedic Implant Assembly
• Brief Description: The ’008 patent relates to an orthopedic implant assembly for joining bone segments. The assembly comprises a stabilizing plate with bores, a securing element (e.g., bone screw) insertable through the bores, and a biased stopping member within the bore to inhibit the securing element from loosening or backing out of the bone.

3. Grounds for Unpatentability

Ground 1: Claims 1, 2, 4, 10, 12-19, 21, 29, 31-32, and 36 are obvious over Theken in view of Errico.

• Prior Art Relied Upon: Theken (Patent 6,228,085) and Errico (WO 1996/032071).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Theken discloses a complete bone fixation system with all elements of the independent claims except for the specific type of stopping member. Theken teaches a bone plate, bone screws, and uses set screws as stopping members to prevent back-out. Errico discloses a "simple and effective" alternative locking mechanism—a biased snap-ring (retaining ring) disposed in an annular recess within a bone plate’s bore—for the same purpose of preventing screw back-out. The snap-ring in Errico is a biased stopping member that defines a reversibly expandable passageway, as required by the claims.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine these references because Theken expressly teaches that its set screws "could be replaced by other suitable locking mechanisms." Errico provides just such a suitable, well-known alternative. The motivation would be to achieve the predictable result of preventing screw back-out by substituting one known locking element for another. Additional motivations included reducing surgical complexity (the "fiddle factor" of handling small set screws), avoiding cross-threading, and minimizing patient risk from lost hardware.
  • Expectation of Success: A POSITA would have a high expectation of success, as both references address the same technical problem in the same field. Incorporating Errico's snap-ring into Theken's plate bore would have been a routine design modification.

Ground 2: Claims 3, 5, 11, 22, 30, and 37 are obvious over Theken in view of Errico.

• Prior Art Relied Upon: Theken (Patent 6,228,085) and Errico (WO 1996/032071).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground targets dependent claims that add limitations related to variable-angle screw functionality. Petitioner asserted that Theken explicitly contemplates using variable-angle screws, suggesting its screw’s tapered head could be replaced with a "spherical head" to "allow variable screw angulation." Errico also teaches the benefits and use of variable-angle bone screws.
  • Motivation to Combine: A POSITA, seeking to implement the variable-angle functionality suggested by Theken, would have been motivated to apply the known screw retention technology from Errico (the snap-ring) to a variable-angle version of Theken’s system. This combination would achieve the known benefits of both variable angulation (better surgical options) and reliable screw retention without the drawbacks of set screws.
  • Expectation of Success: Success would be expected, as the principles of using a snap-ring for retention apply equally to fixed-angle and variable-angle screws.

Ground 3: Claims 3, 5, 11, 22, 30, and 37 are obvious over Theken in view of Errico and Farris.

• Prior Art Relied Upon: Theken (Patent 6,228,085), Errico (WO 1996/032071), and Farris (WO 1998/051226).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground adds Farris to further support the obviousness of the variable-angle claims challenged in Ground 2. Petitioner argued that Farris provides extensive, detailed teachings on implementing variable-angle bone screws, including designs with spherical heads that seat within corresponding spherical recesses in a bone plate.
  • Motivation to Combine: Farris provides a technical roadmap for implementing the variable-angle screw concept suggested by Theken. A POSITA, motivated by Theken and Errico to create a variable-angle system with snap-ring retention, would have looked to references like Farris for specific, known, and proven techniques on how to engineer the screw head and plate bore geometry to achieve the desired angular displacement. Farris confirms the feasibility and desirability of such a system.

4. Key Claim Construction Positions

• "collar" / "annular collar": Petitioner argued this term should be construed to encompass a discontinuous retaining ring or snap-ring, as depicted in the patent’s own figures. This construction is critical for mapping the snap-ring taught in the Errico reference directly onto the claim language.
• "longitudinally and angularly displacing the head": Petitioner contended this method step refers to the tilting of the screw head after it is positioned past the stopping member but not necessarily after it is fully seated or fixed in the patient's bone. This allows prior art teaching angular adjustment during insertion to be applied to the method claims.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under 35 U.S.C. § 325(d) or the General Plastic factors would be inappropriate. They asserted this is not a serial petition, as Petitioner (NuVasive, Inc.) is a separate and unrelated entity to the petitioner (DePuy Synthes) that filed previous, unsuccessful IPRs against the ’008 patent.
• Crucially, Petitioner argued that the primary prior art references and combinations asserted here—specifically Theken and Farris—were never previously presented to or considered by the Patent Office during prosecution or in the prior IPRs. Therefore, the petition raised a fundamentally different patentability challenge that merits consideration.

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-5, 10-19, 21-22, 29-32, and 36-37 of Patent RE43,008 E as unpatentable under 35 U.S.C. §103.