Written Description Support For Genus Claims In Mechanical Inventions: When Is A Single Species Enough?

The inquiry into the sufficiency of written description support turns on whether the disclosure of the application reasonably conveys to those skilled in the art that the inventor has possession of the claimed subject matter as of the filing date. See Ariad Pharm., Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1351 (Fed. Cir. 2010) (en banc). But when the claim is directed to a genus, is disclosure of a single species sufficient to support the claim? That issue was addressed by Synthes USA, LLC v. Spinal Kinetics, Inc., 734 F.3d 1332, 1338 (Fed. Cir. 2013).

Synthes sued Spinal Kinetics (SK) for infringement of claims directed to an intervertebral implant. The claims at issue in the litigation were added by amendment almost five years into the prosecution of the patent and after SK's accused infringing devices were on the market. Id. at 1341. In relevant part, the claims recite "a central part substantially located between the third and fourth plates, the central part