DCT
4:19-cv-10656
Acantha LLC v. NuVasive Inc
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Acantha LLC (Delaware)
- Defendant: NuVasive, Inc. (Delaware)
- Plaintiff’s Counsel: Caldwell Cassady & Curry; Young & Associates
- Case Identification: 4:19-cv-10656, E.D. Mich., 03/05/2019
- Venue Allegations: Venue is based on Defendant NuVasive, Inc. having a regular and established place of business within the Eastern District of Michigan.
- Core Dispute: Plaintiff alleges that Defendant’s spinal implant systems infringe a patent related to a mechanism for preventing orthopedic screws from backing out of a bone plate.
- Technical Context: The technology relates to orthopedic hardware used in spinal fusion surgery, where securing implants durably to bone is critical for patient outcomes.
- Key Procedural History: The patent-in-suit is a reissue of an earlier patent. Plaintiff alleges it previously licensed the patent to Stryker Corporation. The complaint alleges Defendant had pre-suit knowledge of the patent through direct contact between a NuVasive executive and the inventor, citations to the patent during the prosecution of Defendant’s own patents, and a direct offer to license in 2018.
Case Timeline
| Date | Event |
|---|---|
| 1999-07-08 | U.S. Patent No. RE43,008 Priority Date (Original Application Filing) |
| 2001-07-17 | Original U.S. Patent No. 6,261,291 Issues |
| 2007-08-01 | First NuVasive Helix system receives FDA approval (approx. date) |
| 2007-10-01 | NuVasive Halo system receives FDA approval (approx. date) |
| 2011-03-01 | NuVasive Traverse Plate System receives FDA approval (approx. date) |
| 2011-12-06 | U.S. Reissued Patent No. RE43,008 Issues |
| 2012-07-01 | NuVasive Brigade system receives FDA approval (approx. date) |
| 2013-04-01 | Acantha-Stryker license becomes non-exclusive (approx. date) |
| 2014-07-01 | NuVasive CoRoent XL-F system receives FDA approval (approx. date) |
| 2018-01-01 | Acantha contacts NuVasive to offer a license (approx. date) |
| 2019-03-05 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Reissued Patent No. RE43,008 - "Orthopedic Implant Assembly"
- Patent Identification: U.S. Reissued Patent No. RE43,008, "Orthopedic Implant Assembly," issued December 6, 2011.
The Invention Explained
- Problem Addressed: The patent’s background section identifies a key disadvantage in prior art orthopedic implants used to join bone segments: the tendency of screws or other fasteners to loosen or detach from the bone over time, compromising the stability of the implant (’008 Patent, col. 2:23-26).
- The Patented Solution: The invention is an implant assembly that includes a stabilizing element (e.g., a plate), a securing element (e.g., a screw), and a “stopping member” housed within the plate. This stopping member, such as a biased annular collar, features a reversibly expandable passageway. It allows the head of the securing element to pass through it in one direction during implantation and then contracts, creating a mechanical block that prevents the securing element from backing out (’008 Patent, Abstract; col. 4:31-44). This design aims to provide a durable, secure attachment in a single step (’008 Patent, col. 3:13-20).
- Technical Importance: By integrating the locking mechanism into the plate itself, the invention purports to reduce the time required to attach the assembly and improve implant performance without needing a separate anchor implanted in the bone (’008 Patent, col. 3:9-20).
Key Claims at a Glance
- The complaint asserts "at least one claim," with exemplary infringement analysis for independent claim 59 (Compl. ¶34-35).
- Independent Claim 59 requires:
- An elongated securing element with an enlarged integral portion (the screw).
- An attachment element with a bore to receive the securing element (the plate).
- A biased stopping member within the bore that has a "first configuration" allowing the screw head to pass and a "second configuration" that it returns to, where a "posterior stopping surface" on the member engages an "anterior surface" of the screw head to prevent back-out.
- The complaint does not explicitly reserve the right to assert other claims, but this is standard practice.
III. The Accused Instrumentality
Product Identification
- The NuVasive Helix, Halo, Traverse, Brigade, and CoRoent XL-F families of spinal implant systems (collectively, the “Accused Instrumentalities”) (Compl. ¶21, ¶23, ¶25, ¶27, ¶29, ¶32).
Functionality and Market Context
- The accused products are implant systems and instruments designed for anterior stabilization and fixation of the cervical, lumbar, and thoracolumbar spine (Compl. ¶21, ¶23, ¶25, ¶27).
- The complaint alleges that these systems all employ a "one-step, biased stopping member" in the form of a "canted-coil lock" or a "nitinol spring lock" blocking mechanism, which serves to prevent screw back-out (Compl. ¶20). This mechanism is the core of the infringement allegation.
- The complaint alleges these product families have been sold since at least 2007, suggesting they are established product lines for the Defendant (Compl. ¶22, ¶24).
IV. Analysis of Infringement Allegations
The complaint alleges that the Accused Instrumentalities meet all limitations of at least exemplary claim 59 but does not include the referenced claim chart exhibit (Compl. ¶35). The following chart summarizes the infringement theory based on the narrative allegations in the complaint. No probative visual evidence provided in complaint.
RE43,008 Infringement Allegations
| Claim Element (from Independent Claim 59) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a. an elongated securing element having an enlarged integral portion with a length, an anterior surface, a posterior surface and a transverse dimension; | The screws, including variable angle screws, used with the Accused Instrumentalities, which feature a head (enlarged portion) and a body designed for insertion into bone. | ¶21, ¶27 | col. 4:45-47 |
| b. an attachment element which has an anterior surface and a posterior surface and which has at least one bore extending through the attachment element...and is configured to receive the securing element... | The plates and interbody implants of the Helix, Halo, Traverse, Brigade, and CoRoent XL-F systems, which are designed for fixation to the spine and have bores to receive the securing screws. | ¶21, ¶23, ¶29 | col. 4:26-30 |
| c. a biased stopping member which has a posterior stopping surface, a first configuration...that is elastically deformed to a second configuration as the enlarged portion of the securing member passes...the biased stopping member returning to the first configuration...to engage the anterior surface of the enlarged integral portion... | The "one-step, canted-coil lock" or "nitinol spring lock" blocking mechanism integrated into the attachment plates, which is alleged to function as a one-step biased stopping member that prevents screw back-out after insertion. | ¶10, ¶20, ¶21 | col. 15:1-13 |
- Identified Points of Contention:
- Scope Questions: A central question will be whether the accused "canted-coil lock" or "nitinol spring lock" mechanisms fall within the scope of the claim term "biased stopping member." The analysis will likely focus on whether the structure and operation of the accused locks match the claimed member, which "elastically" deforms and "returns" to a configuration where its "posterior stopping surface" engages the screw head.
- Technical Questions: The complaint does not provide technical details on how the accused locks operate. A key evidentiary question will be whether the accused locks actually possess a "posterior stopping surface" that engages an "anterior surface" of the screw head to block removal, as specifically required by claim 59. The precise mechanics of this interaction will be critical.
V. Key Claim Terms for Construction
The Term: "biased stopping member"
- Context and Importance: This term is the core of the claimed invention. The outcome of the case may hinge on whether the Defendant's "canted-coil lock" or "nitinol spring lock" is construed as a "biased stopping member." Practitioners may focus on this term because its scope will determine whether the accused technology, which may operate on a different specific principle, is covered.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification suggests the term is not limited to a single structure, stating that "a variety of suitable members may be used, as for example, one or more contractible fingers" (’008 Patent, col. 4:21-24). Plaintiff may argue this supports a broader, more functional definition.
- Evidence for a Narrower Interpretation: The primary embodiment described and depicted is an "annular collar" that expands and contracts (’008 Patent, Fig. 3A; col. 4:31-34). Defendant may argue that the claims should be limited to structures that operate in this specific expansive/contractive manner.
The Term: "posterior stopping surface...configured to engage with the anterior surface of the enlarged integral portion"
- Context and Importance: This phrase defines the specific mechanical interaction that achieves the anti-back-out function. Infringement will depend on whether the accused products create this specific surface-to-surface engagement.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The use of the functional term "configured to engage" may support an interpretation that covers any surface on the lock that functionally blocks any corresponding surface on the screw head, regardless of the precise geometry.
- Evidence for a Narrower Interpretation: Figure 5 and the accompanying text describe an embodiment where the "flat anterior surface of the head...will butt up against the posterior surface of the collar" (’008 Patent, Fig. 5; col. 5:20-26). Defendant could argue this limits the claim to a direct, perpendicular surface engagement, potentially distinguishing it from the interaction in a "canted-coil" system.
VI. Other Allegations
- Indirect Infringement: The complaint alleges inducement of infringement by distributors, hospitals, and surgeons, based on Defendant’s alleged actions of advertising, selling, and providing instructions on how to use the Accused Instrumentalities through "promotional materials, its website, and surgical technique guides" (Compl. ¶39-40). The complaint also alleges contributory infringement, asserting that the accused components are especially made for an infringing use and are not staple articles of commerce (Compl. ¶43-44).
- Willful Infringement: The complaint alleges willful infringement based on Defendant's alleged pre-suit knowledge of the '008 patent. The specific facts cited include (1) a NuVasive executive contacting the inventor to express interest in the patent; (2) the '008 patent being cited during the prosecution of several of Defendant’s own patents; and (3) a 2018 offer to license from Plaintiff that was allegedly rebuffed (Compl. ¶14, ¶16, ¶17, ¶48).
VII. Analyst’s Conclusion: Key Questions for the Case
- A central issue will be one of claim construction: can the term "biased stopping member", as defined in the patent, be construed broadly enough to read on the Defendant's "canted-coil lock" and "nitinol spring lock" mechanisms, or is it limited to the specific expanding "annular collar" embodiment described in the specification?
- A key evidentiary question will be one of technical operation: assuming a favorable claim construction, does the accused locking mechanism function in the specific manner required by the claims? In particular, does it feature a "posterior stopping surface" that "engage[s]" the "anterior surface" of the screw head to prevent back-out, and can Plaintiff provide sufficient evidence to prove this interaction occurs?
- A third major question will concern willfulness: The complaint presents specific allegations of pre-suit knowledge, including executive-level contact and patent prosecution citations. A key focus of discovery and trial will be whether these allegations can be substantiated to prove that Defendant’s alleged infringement was willful, which would expose Defendant to the risk of enhanced damages.