Nevro Corp v. Boston Scientific Neuromodulation Corp

1. Case Identification

• Case #: IPR2019-01313
• Patent #: 7,496,404
• Filed: July 15, 2019
• Petitioner(s): Nevro Corp.
• Patent Owner(s): Boston Scientific Neuromodulation Corp.
• Challenged Claims: 1-5, 7, 9, 11-17

2. Patent Overview

• Title: Rechargeable Spinal Cord Stimulation System and Method of Use
• Brief Description: The ’404 patent discloses a rechargeable spinal cord stimulation (SCS) system for treating chronic pain. The system includes an implantable pulse generator (IPG) with a replenishable power source and external charging components, and incorporates battery management and protection circuitry.

3. Grounds for Unpatentability

Ground 1: Claims 1-5 are obvious over Holsheimer, Munshi, Schulman, and Wang

• Prior Art Relied Upon: Holsheimer (Patent 5,501,703), Munshi (Patent 5,411,537), Schulman (Patent 4,197,850), and Wang (Patent 5,702,431).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Holsheimer taught a basic implantable SCS system with an IPG and a detachably connected electrode array. The combination with Munshi rendered obvious the inclusion of a replenishable power source (rechargeable battery) within the IPG and an external charger with primary and secondary coils for transcutaneous recharging. The further combination with Schulman taught the inclusion of protection circuitry to power down the IPG when the battery voltage drops and initiate a power-up sequence upon recharging, addressing the risk of data corruption in volatile memory. Finally, adding Wang rendered obvious the inclusion of alignment circuitry to monitor reflected impedance and indicate proper alignment between the external and internal coils, which improves charging efficiency.
  • Motivation to Combine: A POSITA would combine Holsheimer with Munshi to overcome the known problem of limited battery life in implanted devices, thus avoiding repeated explant surgeries. A POSITA would further incorporate Schulman’s protection circuitry to ensure safe operation and prevent data loss in low-voltage scenarios, a known issue with rechargeable devices. Finally, a POSITA would add Wang's alignment system to solve the known problem of inefficient energy transfer during charging, providing a predictable way to maximize charging effectiveness.
  • Expectation of Success: Petitioner asserted that since all references relate to analogous implantable medical devices and address well-known problems with predictable solutions, a POSITA would have had a high expectation of success in combining their teachings.

Ground 2: Claims 7, 9, and 13-17 are obvious over Holsheimer, Munshi, and Schulman

• Prior Art Relied Upon: Holsheimer (Patent 5,501,703), Munshi (Patent 5,411,537), and Schulman (Patent 4,197,850).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground focused on claims directed to battery management and safety features. Petitioner argued the combination of Holsheimer (base SCS system) and Munshi (rechargeable battery) taught the core implantable system with monitoring circuitry for voltage and charging current. The addition of Schulman rendered obvious the claimed power source protection features. Specifically, Schulman taught using voltage sensors to disconnect stimulation circuitry when the battery voltage falls below a disconnect level and reconnect it when the voltage rises above a reconnect level. Schulman also disclosed initiating a power-on-reset to load safe, preselected parameters when the battery is recharged to a sufficient level.
  • Motivation to Combine: The motivation was to improve the Holsheimer/Munshi rechargeable system with known safety and power management techniques. Because Munshi noted its battery should not be completely discharged but did not detail how to prevent it, a POSITA would have been motivated to look to a reference like Schulman to add protection circuitry that prevents damaging over-discharge and ensures the device functions safely after a low-voltage event.
  • Expectation of Success: The combination involved applying known power management principles from Schulman to the rechargeable stimulator of Munshi, which Petitioner argued was a predictable integration of compatible technologies.

Ground 3: Claims 11-12 are obvious over Holsheimer, Munshi, Schulman, and Rutecki

• Prior Art Relied Upon: Holsheimer (Patent 5,501,703), Munshi (Patent 5,411,537), Schulman (Patent 4,197,850), and Rutecki (Patent 5,330,515).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground targeted claims related to external programming and trial components. Petitioner argued that while Holsheimer taught a basic external programmer, Rutecki provided teachings for a more advanced system. Rutecki disclosed a handheld programming wand that worked in conjunction with a computer-based clinician programmer to adjust stimulation parameters. Rutecki also explicitly taught the use of an "external stimulus generator" for temporary, pre-implantation trials to ensure therapeutic efficacy, which was industry-standard practice. The base system from Holsheimer, Munshi, and Schulman would be modified to include these external components.
  • Motivation to Combine: A POSITA implementing the Holsheimer-based system would have been motivated to incorporate the features of Rutecki to provide more robust programming capabilities and to include a trial stimulator. Using an external trial stimulator, as taught by Rutecki, was a well-known and desirable step to confirm the effectiveness of neurostimulation for a patient before undertaking a permanent implantation procedure.
  • Expectation of Success: Petitioner asserted that Holsheimer and Rutecki described analogous implantable stimulation systems, and a POSITA would have found it predictable to combine Rutecki's well-known external trial and programming features with Holsheimer's system.

4. Key Claim Construction Positions

• Petitioner argued several terms should be construed as means-plus-function terms under §112(6), identifying the function and corresponding structure from the specification.
  • "means for using household AC power to recharge the rechargeable power source in the power source charger" (Claim 3): Petitioner construed the function as using AC power to charge the external charger's battery and the structure as a charging base station and an AC power line.
  • "means for non-invasively recharging the replenishable power source through the skin" (Claim 15): Petitioner construed the function as non-invasive charging and the structure as an external power source, power amplifier, an external coil, and an internal coil.
• For the term "alignment between the primary and secondary coils" (Claim 1), Petitioner noted that the prior art disclosed this limitation under either the Patent Owner's proposed construction or the Board's broader construction from a related case, and thus a specific construction was not necessary for the petition.

5. Relief Requested

• Petitioner requested the institution of an inter partes review and cancellation of claims 1-5, 7, 9, and 11-17 of the ’404 patent as unpatentable.