Synthes v. Spinal Kinetics – When “Structure” is Not Enough

A guest post from Domenico Ippolito of Schwegman Lundberg & Woessner, P.A.

Synthes USA, LLC v. Spinal Kinetics, Inc., 2013-1047, -1059, (Fed.Cir. Oct 29, 2013) concerns a medical device patent, but addresses issues common to all patents.  The primary issue was whether Synthes’ claims on a synthetic intervertebral implant (i.e., a spinal disc) were supported by a sufficient written description.  The question had been submitted to a jury, which determined that the written description requirement was not met.  The patentee requested JMOL from the district court judge (Judge Whyte, of the Northern District of California), but the court found substantial evidence supporting the jury’s decision.  The basis of the court’s opinion was that the patent described only a system in which the center layer of the disc was attached to the outer layers via “grooves” penetrating from the circumference of the outer layers, but the claims were directed to “openings.”  Thus, a reasonable jury could find that the claims directed to openings lacked adequate support.

At the Federal Circuit, the majority, Judges O’Malley and Prost, affirmed the district court’s decision, while Judge Taranto dissented.  The Court noted that a jury verdict will be upheld so long as “substantial evidence” supports it, even if evidence “would allow us to draw a different conclusion.”  (Emphasis by the Court.)  By contrast, the dissent emphasized that Spinal Kinetics had not met the burden of proving “by clear and convincing evidence” that the written description requirement was not met.

The test applied by the Court in determining whether or not the disclosure of a single species allows claims directed to a genus is whether other members “of the genus would perform similarly to the disclosed member[].”  The primary evidence relied on by the Federal Circuit was the testimony of an expert provided by the accused infringer.  The Court noted that the expert’s testimony established that 1) the disclosure of grooves was not a disclosure of holes and 2) “there are significant biomechanical property differences between using peripheral grooves and interior slots.”[1]  The first point merely establishes that we are in a species-to-genus situation, but does not establish a lack of written description.  The second point arguably leads to the conclusion that the claims were improperly extended to cover alleged embodiments not actually described by the application.

The Court also cited testimony by a second expert, establishing that the shape and location of the slots was an important design decision that affected the rate of wear on the device and that Spinal Kinetics “had to overcome technical hurdles through its development process.”  To me, this seems more concerned with enablement than written description, but the Court found it to be “at least circumstantial evidence” that “the written description did not support the broad claim limitations in the asserted claims.”

The distinction between written description and enablement seems particularly blurry in cases such as this, where disclosure of a species is used to support a genus claim.  With respect to enablement, the question is whether one of ordinary skill in the art would be enabled to practice the claimed invention “without undue experimentation.”  In re Wands, 858 F.2d 731, 737, 8 U.S.P.Q. 2d 1400, 1404 (Fed. Cir. 1988).  Thus, if the degree of experimentation required to obtain a working disc using openings given only a disclosure of grooves were “undue,” then opening-based embodiments would not be enabled.  By contrast, the question of whether or not the disclosure of a single species allows claims directed to a genus depends on whether other members “of the genus would perform similarly to the disclosed member[].”  This appears to require a much closer relationship to the disclosed embodiments than the enablement requirement, as an embodiment is enabled even if it performs differently, so long as the experimentation required is not “undue.”  By contrast, if the claimed embodiments all perform “similarly,” intuition suggests that the experimentation required will be minimal.

For those of us prosecuting patents, this case stands as a reminder to aggressively brainstorm possible embodiments and include them in the specification.  It seems likely that a single line in the specification generalizing grooves to openings would have avoided the finding of invalidity for lack of written description.



[1] The Court also noted that the expert testified that the distance from the axis to the opening was different for an interior hole than a peripheral groove, but further noted that this testimony was at least partially contradicted by the expert’s admission on cross-examination that deep grooves could also provide the desired distance of the opening from the axis.  The majority found that this admission amounted to little, because it was up to the jury to decide how to balance information weighing in different directions.  The dissent found this to be a critical element that undercut the jury’s determination.

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