In a split decision turning on claim construction, the U.S. Court of Appeals for Federal Circuit affirmed a jury verdict that patents directed to wound healing by application of suction were not shown to be invalid for being obvious.   The Court further affirmed the jury verdict that the patents were not unenforceable, not invalid for indefiniteness and not infringed.  Kinetic Concepts, Inc. v. Blue Sky Medical Group, Inc., Case Nos. 07-1340, -1341, -1342 (Fed. Cir., Feb. 2, 2009) (Prost, J.; Dyk, J., dissenting).

This case is noteworthy for the Court’s claim construction and discussion of conflicting expert testimony.   The patents at issue in this case were directed to apparatuses and methods for treating wounds by applying suction.  The issue of invalidity for obviousness turned on the construction of the term “treating a wound” and on the credibility of conflicting experts.  The principle prior art developed at trial described treatment of fistulae, which are abnormal connections between two organs or vessels that normally do not connect, among other ailments.  Kinetic, the patent holder, distinguished the prior art at trial by arguing that the term wound does not cover the fistulae and other ailments described in the prior art.  The Federal Circuit agreed with this construction.  The Court based its reasoning on the fact that the examples in the specification describe surface or skin wounds.  According to the Court, expanding the term wound to include fistulae would expand the scope of the claims far beyond anything described in the specification.  Justice Dyk dissented, arguing that the Court was reading a limitation into the claims to preserve validity and that the patent was invalid as obvious.  Nonetheless, the two-judge majority concluded that the claim term should be construed in the context of the specification.

The Court further held that there was substantial evidence in the record for the finding of non-obviousness despite contradictory evidence.  The Court, applying U.S. Court of Appeals for the Fifth Circuit law, held that the jury was correctly instructed that it was the sole judge of credibility.  The Federal Circuit explained that, under Fifth Circuit jurisprudence, in cases of conflicting expert testimony, the jury is entitled to make credibility determinations and believe the witness it considers more trustworthy.  Based on this rationale, the Federal Circuit found that the district court record was sufficient to allow the jury to reach its conclusion that the prior art did not teach methods to treat a wound with negative pressure as required by the claims.