NEVRO CORP. v. Boston Scientific Neuromodulation Corp.

1. Case Identification

• Patent #: 8,646,172
• Filed: November 3, 2017
• Petitioner(s): Nevro Corp.
• Patent Owner(s): Boston Scientific Neuromodulation Corp.
• Challenged Claims: 1-11

2. Patent Overview

• Title: Method of Manufacturing a Stimulation Lead
• Brief Description: The ’172 patent describes a method for manufacturing an implantable electrical stimulation lead. The method involves providing a lead body with multiple conductor lumens, placing non-conductive material into those lumens such that it is disposed radially beneath conductive contacts, and heating the material to cause it to thermally reflow or melt, thereby sealing void spaces.

3. Grounds for Unpatentability

Ground 1: Claims 1-5 are obvious over Stolz in view of Ormsby and Black.

• Prior Art Relied Upon: Stolz (Application # 2003/0199950), Ormsby (WO 00/35349), and Black (Patent 6,216,045).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Stolz teaches the foundational elements of independent claim 1, including a method of making a stimulation lead with a lead body comprising a central lumen and a plurality of surrounding conductor lumens containing conductor wires. Stolz also disclosed placing non-conductive material (epoxy) into an "isolation space" radially beneath the conductive contacts and reflowing a distal tip to partially seal the lumens. This base teaching, however, could leave undesirable empty void spaces within the lumens.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSA) would have been motivated to improve upon Stolz's design to eliminate these voids, which could lead to kinking or damage. Ormsby provided the express motivation for this, teaching that filling empty lumen spaces in medical catheters prevents kinking and crushing. To implement this, a POSA would have looked to known techniques, such as that taught by Black. Black disclosed a specific technique of heating and reflowing solid, non-conductive spacers to fill empty regions within a conductor lumen, including the space beneath contacts, to create a solid, "isodiametric" lead free of gaps. A POSITA would combine Stolz's lead structure with Ormsby's motivation to fill voids and Black's specific technique for doing so by reflowing material.
  • Expectation of Success: Petitioner asserted that combining these known elements to solve a known problem would have been a matter of applying known techniques to a predictable art. A POSA would have had a reasonable expectation of success in filling the voids in a Stolz-type lead using the reflowing method taught by Black to achieve the benefits described in Ormsby.

Ground 2: Claims 6-11 are obvious over Stolz in view of Ormsby, Black, and Modern Plastics Encyclopedia.

• Prior Art Relied Upon: Stolz (Application # 2003/0199950), Ormsby (WO 00/35349), Black (Patent 6,216,045), and Modern Plastics Encyclopedia (a 1986 printed publication).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground addressed claims 6-11, which added the limitation of heating the non-conductive material within a specific temperature range (140-250°C) for a specific time period (15-120 seconds). Petitioner argued that the combination of Stolz, Ormsby, and Black rendered obvious all elements of claim 6 except for these specific process parameters. The incremental reference, Modern Plastics Encyclopedia, was introduced to show that selecting such parameters was a matter of routine optimization. The Encyclopedia, a standard industry reference, disclosed reflowing/glass transition temperatures for various polymers, including polyurethane (a material disclosed in both Stolz and Black), that overlap with the claimed range (e.g., 120-160°C for polyurethane thermoplastics).
  • Motivation to Combine: Once motivated to use a reflowing process as established in Ground 1, a POSA would have naturally sought to determine the optimal temperature and time for the operation. A POSA would consult a standard reference like the Modern Plastics Encyclopedia to find a workable starting point for the specific polymer being used and would optimize from there. The petition argued that the ’172 patent ascribed no criticality or unexpected results to the claimed ranges, reinforcing their obviousness.
  • Expectation of Success: Petitioner contended that determining appropriate time and temperature ranges for a thermal process is routine experimentation for a POSA. Given the known principles of heat transfer and the documented properties of polymers in references like the Encyclopedia, a POSA would have reasonably expected to arrive at a successful process within the claimed ranges without undue experimentation. Dependent claims 7-11 added further conventional features, such as specifying eight lumens (a number falling within the range disclosed by Stolz) or using polyurethane (a material expressly disclosed by Stolz and Black), which Petitioner argued were obvious selections of known options.

4. Key Claim Construction Positions

• Petitioner argued that the claims of the ’172 patent should be given their broadest reasonable interpretation and that no special claim constructions were necessary. The petition noted that the patentee did not act as its own lexicographer for any term except "lead," which the specification broadly defined as "an elongate device having any conductor or conductors, covered with an insulated sheath and having at least one electrode contact." Petitioner asserted that its invalidity arguments succeed even under this broad, patentee-defined construction.

5. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 1-11 of Patent 8,646,172 as unpatentable under 35 U.S.C. §103.