DCT
1:25-cv-00546
Stratus Medical LLC v. Avanos Medical Inc
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Stratus Medical, LLC (Utah/Texas)
- Defendant: Avanos Medical, Inc. (Delaware/Georgia) and Diros Technology, Inc. (Canada)
- Plaintiff’s Counsel: Richards, Layton & Finger, P.A.; Foley & Lardner LLP
- Case Identification: 1:25-cv-00546, D. Del., 05/02/2025
- Venue Allegations: Venue is alleged to be proper in Delaware because Defendant Avanos is a Delaware corporation and Defendant Diros, a foreign corporation, has committed acts of infringement in the district.
- Core Dispute: Plaintiff alleges that Defendants’ Trident™ line of radiofrequency cannulae infringes three U.S. patents related to medical devices for performing radiofrequency neurotomy.
- Technical Context: The technology pertains to radiofrequency (RF) ablation needles used in neurotomy procedures to treat chronic pain by destroying specific nerve tissues.
- Key Procedural History: The complaint alleges that Defendant Diros was previously sued in Australia in 2019 over counterpart patents and subsequently ceased selling the accused products there. Defendant Avanos acquired Diros in July 2023. On July 26, 2024, Defendants filed inter partes review (IPR) proceedings challenging the validity of all three patents-in-suit, an event Plaintiff cites to establish Defendants' knowledge of the patents.
Case Timeline
| Date | Event |
|---|---|
| 2009-11-05 | Earliest Priority Date ('664, '688 Patents) |
| 2010-06-23 | Earliest Priority Date ('782 Patent) |
| 2019-01-01 | Australian litigation filed against Diros (NSD 438 of 2019) |
| 2020-08-11 | '688 Patent Issued |
| 2021-02-23 | '664 Patent Issued |
| 2021-04-06 | '782 Patent Issued |
| 2023-07-24 | Avanos completes acquisition of Diros |
| 2024-07-26 | Defendants file IPRs against the '664, '782, and '688 Patents |
| 2025-05-02 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 10,925,664 - Methods for Radio Frequency Neurotomy
The Invention Explained
- Problem Addressed: The patent’s background section describes the limitations of conventional radiofrequency (RF) neurotomy, where a single probe creates a generally oval or spheroid lesion. This makes it challenging to ensure the target nerve is fully encompassed, particularly when anatomical variations exist or access to the nerve is limited ('664 Patent, col. 1:40-54).
- The Patented Solution: The invention is a method for performing RF neurotomy that uses a needle with multiple deployable filaments that extend from its tip. This arrangement expands the effective area of RF energy delivery, allowing for the creation of larger, directionally-shaped lesions that can be positioned asymmetrically relative to the needle's central axis ('664 Patent, col. 2:5-20). This method allows a physician to move the needle tip to a position near a target nerve, deploy the filaments, and then apply RF energy to create a lesion specifically shaped and positioned to ablate the nerve ('664 Patent, col. 2:55-65).
- Technical Importance: The method provides physicians with greater control over the size, shape, and location of the RF lesion, which may lead to more effective and reproducible nerve ablation for pain relief ('664 Patent, col. 3:10-18).
Key Claims at a Glance
- The complaint asserts at least independent claim 1 (Compl. ¶27).
- Claim 1 is a method claim comprising the essential steps of:
- Inserting a needle into a patient, the needle containing an elongate member, a tip, a lumen, and a movable filament.
- Moving the filament to a deployed position where at least a distal end is out of the elongate member.
- Inserting an RF probe into the lumen to contact a conductive portion of the needle.
- Operating the RF probe, tip, and filament together as a single monopolar electrode to conduct RF energy to the filament.
- The complaint reserves the right to assert additional claims (Compl. ¶30).
U.S. Patent No. 10,966,782 - Needles and Systems for Radiofrequency Neurotomy
The Invention Explained
- Problem Addressed: Similar to the '664 Patent, the background addresses the difficulty in creating precisely shaped and located lesions with standard RF probes, which can limit the effectiveness of neurotomy procedures for pain management ('782 Patent, col. 1:39-50).
- The Patented Solution: The patent claims the apparatus itself: a needle system for RF neurotomy. The core of the apparatus is a needle with an elongate member, a hub, a tip, and a plurality of deployable filaments disposed within the member ('782 Patent, col. 2:1-12). An actuator mechanism allows a user to move the filaments from a retracted position (for insertion) to a deployed position where they extend from the needle tip to create a larger, multi-point electrode for delivering RF energy ('782 Patent, col. 2:25-34).
- Technical Importance: This apparatus provides the physical tool to perform the methods described in related patents, enabling the creation of larger and asymmetrically shaped lesions to improve clinical outcomes in pain management procedures ('782 Patent, col. 1:63-2:4).
Key Claims at a Glance
- The complaint asserts at least independent claim 1 (Compl. ¶37).
- Claim 1 is an apparatus claim comprising the essential elements of:
- An elongate member with a distal end.
- A tip coupled to the distal end.
- A plurality of filaments movable between a first (retracted) and second (deployed) position.
- The filaments and tip are configured to transmit RF energy from a probe to operate as a monopolar electrode.
- The complaint reserves the right to assert additional claims (Compl. ¶40).
U.S. Patent No. 10,736,688 - Methods and Systems for Spinal Radio Frequency Neurotomy
- Technology Synopsis: This patent describes methods and systems for spinal RF neurotomy using needles with deployable filaments capable of applying RF energy asymmetrically relative to the needle's central axis ('688 Patent, Abstract). The goal is to ablate target nerve volumes, such as medial branch nerves or rami, to denervate joints and relieve pain while facilitating easier placement of the needle by the physician ('688 Patent, Abstract).
- Asserted Claims: The complaint asserts at least independent claim 1 (Compl. ¶¶52, 59).
- Accused Features: The complaint alleges that the Diros Trident DTR (when combined with an RF probe) and DTRH cannulae infringe by constituting the claimed system and being used to perform the claimed methods (Compl. ¶¶51, 59).
III. The Accused Instrumentality
Product Identification
- The accused products are the Diros Trident™ RF Cannulae model DTR ("DTR") and the Diros Trident™ RF Hybrid Cannulae model DTRH ("DTRH") (Compl. ¶18).
Functionality and Market Context
- The DTR and DTRH are radiofrequency needles used for RF medical procedures (Compl. ¶18). The primary functional difference is that the DTR model requires a separate RF probe and temperature sensor to be inserted into its lumen, while the DTRH model has these components permanently installed (Compl. ¶19). The complaint alleges that a key feature of the Accused Products is their use of "deployable tines that create a 'shaped lesion whose large base encompasses the nerve'" (Compl. ¶20). This functionality is central to the infringement allegations. Defendants market the products as "innovative" (Compl. ¶22). No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
The complaint references, but does not include, claim chart exhibits. The following tables are constructed based on the narrative allegations in the complaint synthesized with the patent claims and specification, reflecting an expert analysis of the asserted infringement theory.
'664 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A method comprising: inserting a needle into a patient... | A doctor or other end user inserts an Accused Product (DTR or DTRH) into a patient to perform an RF procedure. | ¶27 | col. 2:46-52 |
| moving a filament, which is in a retracted position...to a deployed position wherein at least a distal end of the filament is out of the elongate member... | The end user deploys the "deployable tines" of the Accused Product, which the complaint alleges function as the claimed filaments. | ¶20 | col. 2:25-30 |
| inserting a radiofrequency probe into the lumen of the needle such that the radiofrequency probe contacts a conductive portion of the needle... | For the DTR model, the end user inserts a separate RF probe into its lumen. For the DTRH model, the probe is pre-installed. | ¶19 | col. 2:10-15 |
| operating the radiofrequency probe, the tip, and the filament as a single monopolar RF electrode... | The end user operates the Accused Product in combination with an RF generator to deliver RF energy to ablate nerve tissue. | ¶29 | col. 2:1-5 |
'782 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A needle...comprising: an elongate member having a distal end; | The cannula body of the DTR and DTRH products. | ¶18 | col. 2:1-4 |
| a tip coupled to the distal end of the elongate member; | The bare tip of the DTR and DTRH cannula. | ¶20 | col. 2:3-4 |
| a plurality of filaments, wherein the plurality of filaments is movable between a first position at least partially in the elongate member and a second position...partially out of the elongate member; | The "deployable tines" of the DTR and DTRH products, which can be moved from a retracted to a deployed state. | ¶20 | col. 2:5-10 |
| wherein the plurality of filaments and the tip are configured to transmit radio frequency energy from a probe to operate as a monopolar electrode. | The DTR is designed to be used with an RF probe in a monopolar mode, and the DTRH has an integrated probe for the same function. | ¶19, ¶29 | col. 2:13-17 |
- Identified Points of Contention:
- Scope Questions: The central dispute may turn on claim construction. A primary question will be whether the accused "deployable tines" fall within the scope of the claim term "plurality of filaments." Defendants may argue for a narrower construction of "filaments" based on specific embodiments in the patents, while Plaintiff will likely argue for a broader, functional definition.
- Technical Questions: For the method claims ('664 Patent), a potential question is whether the instructions for use and customary medical practice of the Accused Products result in doctors performing every step of the asserted claims. For the apparatus claims ('782 Patent), the dispute will focus on whether the physical structure of the DTR and DTRH products meets each limitation of the asserted claims.
V. Key Claim Terms for Construction
- The Term: "plurality of filaments"
- Context and Importance: This term appears in the independent claims of both the '664 and '782 patents and is the central technical feature of the invention. The complaint alleges that the "deployable tines" of the accused products correspond to this element (Compl. ¶20). Therefore, the construction of "filaments" will be critical to determining whether the accused products infringe.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification describes the invention's purpose as expanding "the effective area of RF energy delivery" ('664 Patent, col. 3:10-12) and providing "additional conduits for RF energy" ('664 Patent, col. 3:13-14). This functional language may support a construction that encompasses any deployable conductive element, such as a "tine," that achieves this purpose.
- Evidence for a Narrower Interpretation: The detailed descriptions and figures often depict the filaments as thin, wire-like structures (e.g., '782 Patent, Fig. 2A, 2E). Defendants may argue that these specific embodiments limit the term "filament" to structures with a high aspect ratio, potentially distinguishing them from the "tines" in their products if those tines have a different geometry (e.g., flatter or more blade-like).
VI. Other Allegations
- Indirect Infringement: The complaint alleges both induced and contributory infringement for all three patents-in-suit.
- Inducement: The allegations are based on Defendants' distribution of product literature and website materials that allegedly instruct and encourage end-users (doctors) to use the Accused Products in a manner that directly infringes the patents (Compl. ¶¶26, 36, 51).
- Contributory Infringement: The complaint alleges the DTR product is especially designed for use in an infringing manner and has no substantial non-infringing uses when combined with an RF probe for monopolar operation, a combination Defendants allegedly knew would be infringing (Compl. ¶¶29, 39, 54).
- Willful Infringement: While the complaint does not contain a separate count for "willful infringement," it lays a foundation for such a claim. It alleges Defendants had knowledge of their infringement based on pre-suit litigation against Diros in Australia on counterpart patents (Compl. ¶28) and, more pointedly, based on Defendants' own act of filing IPR proceedings against all three patents-in-suit on July 26, 2024, nearly a year before the complaint was filed (Compl. ¶¶25, 35, 50).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of definitional scope: can the term "plurality of filaments," as used in the patents in the context of RF neurotomy needles, be construed to cover the "deployable tines" featured in the accused Diros Trident™ cannulae, or is there a material structural or functional distinction?
- A second central question will concern scienter and intent: what evidence establishes the timeline of Defendants' knowledge of the patents-in-suit, particularly in light of the prior Australian litigation and, more significantly, their own filing of inter partes review proceedings, and does this evidence satisfy the specific intent requirement for induced infringement?
- An underlying validity question, raised by Defendants' own IPR filings, will be patentability: will the patents-in-suit withstand the validity challenges asserted by Defendants before the Patent Trial and Appeal Board and, potentially, before the district court, which could render the infringement analysis moot?