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"Comprising" Criticized as "Weasel Word"

December 12, 2001

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Last Month at the Federal Circuit - January 2002

Judges: Newman (author), Gajarsa, and Michel (dissenting)

The Federal Circuit vacated a SJ finding of noninfringement in Smith & Nephew, Inc. v. Ethicon, Inc., No. 00-1160 (Fed. Cir. Dec. 12, 2001). Smith & Nephew, Inc. ("S&N") filed suit against Ethicon, Inc. ("Ethicon") for infringement and induced infringement of the claims of its U.S. Patent No. 5,601,557 ("the '557 patent") directed to a method for anchoring tissue to bone. According to the district court's construction, the claimed method requires a suture anchor with resilient legs to be lodged in the bone after insertion (the resilient legs returning to their natural position makes the anchor immovable). The district court also had found that the claims did not preclude manipulation of the anchor after insertion in the bone, and that the written description instructed users to apply tension (e.g., tugging) to ensure that the anchor was seated.

The Federal Circuit affirmed the district court's claim construction over Ethicon's arguments of prosecution history estoppel and dedication to the public. It further clarified that the claims of the '557 patent neither required nor excluded a postinsertion-tensioning step to lodge the anchor. In reaching its conclusion, the Court explained that the claim, which contained "comprising" as the transition signal, could be practiced with steps in addition to those listed in the claims.

With respect to infringement, Ethicon argued that its device, which had legs that could be manipulated after insertion, required a tensioning step (e.g., tugging) by a surgeon to lodge the anchor in the bone. The district court agreed, finding that because the tensioning step is required to lodge the Ethicon device, the use of Ethicon's device could not infringe the '557 patent claims. On appeal, S&N disputed that Ethicon's device in fact required a tensioning step and argued that even if tensioning were required, the use of Ethicon's device infringed the claims of the '557 patent because a surgeon using Ethicon's device necessarily performs all of the steps of the claimed method prior to the tensioning step.

The Federal Circuit ruled that a disputed material fact existed as to whether the Ethicon anchor was "lodged" in the bone within the meaning of the district court's claim construction. The Court reasoned that Ethicon's product literature did not require the tensioning step and found that the parties did not dispute that the legs of Ethicon's accused anchors returned to their relaxed position after insertion and could not be removed. Based on that finding, the majority vacated the district court's entry of SJ.

In dissent, Judge Michel took issue with the district court's claim construction, reasoning that the tensioning step was outside the scope of the asserted claims. According to him, the prosecution history and the inventor's testimony both touted that the invention did not require a postinsertion manipulation, i.e., tensioning, to lodge the anchor. Therefore, he concluded, the majority had added a step to the claimed method that the inventor himself had given up. Further, he observed that the tugging instruction in the written description of the '557 patent did not appear in any claim–and was specifically eliminated by one of the claims of the '557 patent–which dedicated that separate step to the public. Judge Michel characterized the majority's view as permitting the use of the signal "comprising"– which he characterized as a "weasel word"–to obliterate the dedication to the public rule of Maxwell v. J. Baker, Inc., 86 F.3d 1098 (Fed. Cir. 1996), and to permit the recapture of disclaimed subject matter.

With respect to infringement, Judge Michel opined that S&N had offered no evidence to dispute Ethicon's evidence and that postinsertion tensioning of the anchor was required to use its device. Moreover, Ethicon's device did not have resilient legs and, therefore, did not contain an element of the claimed invention. For these reasons, Judge Michel concluded, no reasonable juror could have concluded that the use of Ethicon's device infringed the claim of the '557 patent and entry of SJ was proper.