Mako Surgical Corp. v. Blue Belt Technologies, Inc.

1. Case Identification

• Case #: Unassigned
• Patent #: 6,757,582
• Filed: January 28, 2015
• Petitioner(s): Mako Surgical Corp. and Stryker Corporation
• Patent Owner(s): Blue Belt Technologies, Inc.
• Challenged Claims: 1, 3, 5-14, 16-30, 34-42, and 47-58

2. Patent Overview

• Title: Methods and Systems to Control a Shaping Tool
• Brief Description: The ’582 patent relates to systems and methods for controlling a cutting tool to shape a workpiece. While the claims are broad, the specification primarily describes applications in high-precision surgery, where a controller uses tracking data from markers on a tool and a workpiece (e.g., a bone) to guide the tool's movement relative to a target shape, thereby avoiding the need for invasive physical clamps.

3. Grounds for Unpatentability

Ground 1: Claims are anticipated by or obvious over Taylor

• Prior Art Relied Upon: Taylor (Russell H. Taylor et al., An Image-Directed Robotic System for Precise Orthopaedic Surgery, IEEE Transactions on Robotics and Automation, June 1994), Glassman (Patent 5,408,409), DiGioia (Patent 6,205,411), and Delp (Scott L. Delp et al., An Interactive Graphics-Based Model of the Lower Extremity to Study Orthopaedic Surgical Procedures, 1990).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Taylor, published nearly a decade before the ’582 patent’s priority date, discloses an "image-directed robotic system" that anticipates the independent claims. Taylor’s system included a cutting tool ("ball probe cutter bit"), a workpiece with a target shape (a bone with a planned implant shape), a tracker (a Northern Digital Optotrak™ digitizer tracking markers on the tool and workpiece), and a controller that stops the tool if it strays from a predefined volume. Petitioner asserted this maps directly to the elements of independent claims 1, 17, and 24. Several dependent claims were argued to be inherently disclosed, such as tracking based on position and angle (claim 6) and the use of collision detection (claim 16).
  • Motivation to Combine (for §103 grounds): For claims not fully anticipated by Taylor alone, Petitioner contended a person of ordinary skill in the art (POSA) would combine Taylor with other known art. For example, a POSA would look to Glassman (co-authored by Taylor) for its teaching of a "rotatable blade" (a drill) to satisfy claim 3. A POSA would also combine Taylor with DiGioia to use infrared markers on the workpiece (claim 7), as Taylor already used them on the cutting tool. Finally, common display functions like zooming, taught by Delp, would be an obvious addition to satisfy claims 48-49.
  • Expectation of Success: A POSA would have a high expectation of success as these combinations involved applying known techniques (e.g., different marker types, common UI features) to a known system to achieve predictable results.

Ground 2: Claims are anticipated by or obvious over Burghart

• Prior Art Relied Upon: Burghart (Catherina Burghart et al., Robot Controlled Osteotomy in Craniofacial Surgery, June 1999), Taylor, and Delp.
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Burghart, a 1999 workshop article, also anticipates the independent claims. Burghart described a system for precision bone surgery using a surgical saw on a robot flange, controlled by a surgeon. The system tracked the positions of the tool and the patient's skull (the workpiece) using an infrared (IR) system with CCD cameras and IR diodes. A controller evaluated the tool's position within a "defined safety zone" relative to a planned trajectory. This was argued to disclose all elements of independent claims 1, 17, and 24.
  • Motivation to Combine (for §103 grounds): For claims requiring elements not explicitly in Burghart, such as voxel-based modeling (claim 21), Petitioner argued it would be obvious to combine Burghart with Taylor. Taylor was a well-known, foundational paper in the field that explicitly taught using pre-surgical voxel systems. A POSA seeking to improve Burghart's system would have been motivated to incorporate Taylor's established imaging and planning methods. Similarly, it would be obvious to use a CAD model for the cutting tool, as taught in Taylor, to improve tracking accuracy.
  • Expectation of Success: Combining Taylor's imaging with Burghart's robotic system would have yielded predictable improvements in surgical planning and execution.

Ground 3: Claims are anticipated by or obvious over DiGioia

• Prior Art Relied Upon: DiGioia (Patent 6,205,411), Taylor, and Delp.
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued DiGioia anticipates the independent claims and qualifies as prior art under §102(a), (b), and (e). DiGioia, which shares inventors with the ’582 patent, described an apparatus for surgical implantation of an artificial joint. It disclosed a system with a surgical tool on a robotic arm, a bone model (workpiece) with a target implant shape, and a control algorithm utilizing tracking data from an Optotrak system to limit the tool's movement to a defined space. Petitioner highlighted that the Patent Owner had asserted both the ’582 patent and DiGioia against the same accused product, underscoring their similarity.
  • Motivation to Combine (for §103 grounds): The petition argued that claims not anticipated by DiGioia would have been obvious over DiGioia in view of Taylor. For example, DiGioia does not explicitly disclose voxel-based workpiece modeling (claim 21). A POSA would have been motivated to implement the pre-surgical voxel imaging and planning system from the well-known Taylor reference into the DiGioia system to improve its functionality.
  • Expectation of Success: Given the substantial overlap in subject matter and inventors between the references, a POSA would have reasonably expected success in combining the voxel-based planning of Taylor with the robotic control system of DiGioia.

4. Key Claim Construction Positions

• Means-Plus-Function Indefiniteness: Petitioner argued that claims 10, 11, 12, and 18 are indefinite under pre-AIA 35 U.S.C. §112, ¶ 6. For the "means to register" (claims 10, 18) and "means to transform tracking data" (claim 12), the ’582 patent specification allegedly failed to disclose a sufficiently definite structure, such as a specific algorithm, required to perform the claimed function, instead stating only that "transformations can be mathematically effectuated."
• "tuning tool image" (Claim 24): Petitioner contended this term, which lacks an antecedent basis, is an obvious typographical error for "cutting tool image" based on the prosecution history. Otherwise, the term renders claim 24 indefinite.
• "4-D image" (Claim 24): Petitioner argued this term renders claim 24 indefinite. During prosecution, the term was changed from "3-D" to "4-D" without any explanation or support in the specification, which only discusses 3-D images. This change allegedly failed to inform a POSA with reasonable certainty about the scope of the invention.

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1, 3, 5-14, 16-30, 34-42, and 47-58 of Patent 6,757,582 as unpatentable.