To be sure, a prosecution disclaimer requires "clear and unambiguous disavowal of claim scope," but applicants rarely submit affirmative disclaimers along the lines of "I hereby disclaim the following . . ." during prosecution and need not do so to meet the applicable standard.

On April 4, 2013, in Saffran v. Johnson & Johnson, the U.S. Court of Appeals for the Federal Circuit (Lourie,* Moore, O'Malley) reversed the district court's judgment that Johnson & Johnson and Cordis Corp. infringed U.S. Patent No. 5,653,760, which related to the treatment of injured tissues within human or animal bodies involving the way injured tissues are joined and macromolecules are directed to promote healing. The Federal Circuit stated:

The term "device" appears in every claim of the '760 patent -- in the preamble and body of independent claim 1, in the bodies of independent claims 8 and 15, and at least by reference in each of the dependent claims. In its Claim Construction Order, the district court nonetheless concluded that, as used in the '760 patent, the term "device" serves only as non-limiting preamble language that does not require a sheet and "merely gives a descriptive name to the set of limitations in the body of the claim that set forth the invention." . . . We conclude that Saffran's statements during prosecution of the '760 patent limit "device" to a continuous sheet. On multiple occasions during prosecution, Saffran sought to distinguish prior art by representing to the examiner that "[t]he device used is a sheet rather than a pre formed chamber (Gaskill)." Saffran contends that his statements merely disclaimed the rigid pre-formed chambers disclosed in U.S. Patent 4,911,717 ("Gaskill") without further limiting the invention to a sheet. While Saffran surely disclaimed preformed chambers during prosecution, we disagree that his statements have such limited import. Saffran's arguments to the examiner presented two bases for distinguishing Gaskill: (i) that his device is a sheet, and (ii) that his device is not a pre-formed chamber. Even if, as Saffran suggests, the examiner had relied only on the latter, that would not annul the remainder of his statement. "Rather, as we have made clear, an applicant's argument that a prior art reference is distinguishable on a particular ground can serve as a disclaimer of claim scope even if the applicant distinguishes the reference on other grounds as well." Furthermore, the record before us makes clear that the examiner shared Saffran's stated view of the claimed device as a continuous sheet. In recording his reasons for allowance, the examiner noted that "[t]he claimed invention embodies a unique method of [macromolecular restraint] using a single flexible minimally porous sheet layer."

To be sure, a prosecution disclaimer requires "clear and unambiguous disavowal of claim scope," but applicants rarely submit affirmative disclaimers along the lines of "I hereby disclaim the following . . ."during prosecution and need not do so to meet the applicable standard. In this case, Saffran's unqualified assertion that "the device used is a sheet" extends beyond illuminating "how the inventor understood the invention," to provide an affirmative definition for the disputed term. Given such definitive statements during prosecution, the interested public was entitled to conclude that the "device" recited in the claims of the '760 patent is a continuous sheet.

Saffran's arguments alleging that the '760 patent contains contrary embodiments are not persuasive. Saffran first contends that the "spray" embodiment disclosed in the '760 patent does not yield an unbroken sheet but forms a layer only where it contacts bone or some other solid surface, such as the struts of a stent. But the record belies that assertion. The figures illustrating the spray embodiment show a spray nozzle depositing a continuous, unbroken sheet that spans open gaps between individual bone fragments. More fundamentally, and as Saffran acknowledged during trial, the '760 patent never mentions spraying the device onto a stent or any other support substrate except the injured tissue itself. On that very basis, in fact, Saffran attempted to distinguish his spray embodiment from a prior art vascular graft (disclosed in U.S. Patent 5,152,782 ("Kowligi")) that was subjected to spray coating before implantation: "The critical difference here is that Kowligi disclose[s] a way to make their device, while I disclose a way to deploy mine." The '760 patent's spray embodiment thus concerns depositing a continuous sheet of material onto injured tissue, not preparing a support structure such as a stent for later implantation into a patient.

The specification supports this conclusion. Throughout its specification, the '760 patent consistently describes the disclosed "device" as a sheet, whether wrapped around a stent, affixed to a fractured bone, or applied as a spray. Extensive, consistent usage in the specification therefore suggests that the claimed "device" should be understood as a sheet, which, rather than confining the term to a single embodiment, would accord with every embodiment and description presented in the '760 patent, not to mention the prosecution history.

Furthermore, the '760 patent emphasizes macromolecular containment as a key feature of the invention, and, in the specific context of vascular stents, expressly relies on the sheet to distinguish the claimed device from prior art open mesh stents. The specification describes the device's ability to restrain tissue macromolecules near the site of injury as a "cardinal" and "exceedingly important" feature of the invention. The specification also criticizes prior art stents as unable to restrain macromolecules between the stent and the vessel wall; according to the '760 patent, prior art stents "are porous meshes" characterized by holes so large that "both cells and large macromolecules are free to move through them." In short, the specification makes clear that restraining tissue macromolecules is not only a key feature of the invention, but also one that open mesh stents cannot provide. Therefore, reading the claim term "device" to both require a sheet and exclude stents having open mesh holes "most naturally aligns with the patent's description of the invention." . . .

Under the correct construction of the term "device," Cordis cannot infringe the asserted apparatus or method claims unless its accused stent products include a continuous sheet and lack uncovered holes in the stent mesh. The accused Cordis stents all exhibit a metallic mesh structure, their struts coated with a thin layer comprising polymer and sirolimus. But that layer is akin to paint on a chain link fence, not a continuous sheet wrapped around the mesh, and open holes remain between the struts of the accused devices -- as Saffran has acknowledged. Therefore, no reasonable jury could conclude that Cordis's accused stents infringe the asserted claims of the '760 patent, and Cordis is entitled to a judgment of noninfringement as a matter of law.