PTAB

IPR2019-01284

Nevro Corp v. Boston Scientific Neuromodulation Corp

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Systems and Methods for Communicating with an Implantable Stimulator
  • Brief Description: The ’480 patent discloses a system for communication between an external device and an implantable medical device, such as a stimulator. The system uses an on-off keying (OOK) modulation technique where data is encoded by varying the length of both the ON portions (pulse width) and OFF portions (pulse interval) of a transmitted signal.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claim 1 under 35 U.S.C. §102 over Grevious

  • Prior Art Relied Upon: Grevious (Patent 6,443,891).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Grevious, which was not considered during prosecution, discloses every limitation of claim 1. Grevious teaches a telemetry system for communicating with an implantable neuro-stimulator that supports multiple modulation formats, including a "Format B" described as pulse width modulation (PWM) plus pulse interval modulation (PIM). Petitioner asserted this Format B encodes data bits into both the ON portions ("bursts") and OFF portions ("not bursts") of the signal by varying their lengths. A pulse or interval of length Tzero is interpreted as a logic ‘0’, while a length of Tone is interpreted as a logic ‘1’. Petitioner contended this directly maps to the ’480 patent's claimed modulation scheme, which requires logic ‘0’ and ‘1’ bits to have different pulse widths, for each bit to comprise either an ON or OFF state, and for transitions between bits to be marked by a change between the ON and OFF states.
    • Key Aspects: The central argument was that Grevious’s "Format B" is the precise modulation technique that the Patent Owner relied on to overcome prior art during prosecution of the ’480 patent.

Ground 2: Obviousness of Claim 1 under 35 U.S.C. §103 over Grevious in view of Fitch

  • Prior Art Relied Upon: Grevious (Patent 6,443,891), Fitch (Patent 4,807,225).
  • Core Argument for this Ground:
    • Prior Art Mapping: As an alternative to anticipation, Petitioner argued that even if Grevious does not expressly disclose every feature of the claimed modulated signal, the combination with Fitch renders it obvious. Fitch discloses a "Pulse Width Encoded – Non Return to Zero (PWE-NRz)" modulation format for RF communications in a telephone line carrier system. This format uses on-off carrier keying where a logic ‘1’ has a duration of 1 ms and a logic ‘0’ has a duration of 2 ms. Petitioner asserted that Fitch’s scheme satisfies all requirements of the claimed "first modulated signal."
    • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine Fitch's modulation scheme with Grevious's system. Grevious already teaches a system supporting numerous modulation formats and explicitly states that other formats are possible. Fitch's scheme was designed to be an inexpensive technique for reliable communication in a noisy environment, a known problem pertinent to implantable medical device telemetry. A POSITA would have been motivated to incorporate Fitch's robust modulation format into Grevious's versatile multi-format system to enhance communication reliability and support a wider array of medical devices.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success because adding a known modulation format to a system designed to be flexible and support multiple formats was a predictable application of known techniques.

Ground 3: Obviousness of Claims 6 and 7 over Grevious in view of Bradshaw

  • Prior Art Relied Upon: Grevious (Patent 6,443,891), Bradshaw (Patent 4,327,441), with or without Fitch (Patent 4,807,225).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground targets dependent claims 6 and 7, which add limitations requiring the data to comprise a "start bit" transmitted before "control bits" and specify circuitry for processing these bits. Petitioner argued that to the extent Grevious does not disclose these features, Bradshaw does. Bradshaw teaches a method for synchronizing and calibrating a pulse width modulation receiver by transmitting a reference pulse (a "start bit") before a number of control function pulses ("control bits"). The receiver uses the width of the reference pulse to generate a bit width threshold, which is then used by counters and a comparator to determine whether subsequent control pulses are logic ‘0’ or ‘1’. This addresses communication errors caused by temperature and age-induced drift.
    • Motivation to Combine: A POSITA would be motivated to incorporate Bradshaw's synchronization technique into the Grevious system to improve communication accuracy. Implantable devices like those in Grevious are subject to the same drift issues that Bradshaw addresses and are difficult or impossible to manually readjust. Bradshaw's technique provides a "simple and straightforward" method for rapid calibration. Therefore, adding this known solution to solve a known problem in the analogous field of implantable device communication would have been obvious.
    • Expectation of Success: Success was expected as it involved applying a known calibration technique (Bradshaw) to a known communication system (Grevious) to achieve the predictable result of improved reliability.
  • Additional Grounds: Petitioner asserted that claims 2-4, 6, and 8 are obvious over Grevious with or without Fitch. This argument relied on the obviousness of incorporating frequency modulation (FSK)—a well-known, alternative communication scheme—into Grevious's versatile telemetry system to provide the claimed "second modulation circuitry."

4. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-4 and 6-8 of Patent 7,822,480 as unpatentable.