In Tyco Healthcare Group LP v. Ethicon Endo-Surgery, Inc., the Federal Circuit agreed with the district court that Ethicon’s prototype constituted prior art under 35 USC § 102(g) based on its earlier date of conception, but reversed the district court’s decision that it could not be used for obviousness purposes because of its later reduction to practice. This case highlights the problem of “secret prior art” that will be ameliorated–but not eliminated–by the first-to-file provisions of the America Invents Act.

The Patents At Issue

The patents at issue were Tyco’s U.S. Patent Nos. 6,682,544, 6,063,050, and 6,468,286, directed to ultrasonic cutting and coagulating surgical devices. As described in the Federal Circuit decision:

The asserted patents generally disclose a surgical device … that employs ultrasonic energy to cut and coagulate tissue in surgery. … The device includes a stationary and movable handle at one end and a shaft with a tube within a tube construction at the other. … A clamp and a curved blade sit at the distal end of the shaft. … The clamp opens and shuts like a jaw against the blade via a dual cam mechanism.

The “Curved Blade Claims” include claim 15 of the ‘286 patent and claims 6 and 8 of the ‘544 patent, which recite a device with a curved blade.

The “Dual Cam Claims” include claim 8 of the ‘286 patent and claims 11 and 12 of the ‘050 patent, which “generally recite that the clamp closes against the blade via a dual cam mechanism that consists of ‘cam members’ or ‘camming members,’ as well as cam ‘slots’.

The District Court Decision

Ethicon asserted that the claims were invalid over prior art including (1) an Ethicon prototype of an ultrasonic surgical device (the “Ethicon Prototype”); (2) U.S. Patent No. 5,322,055 (the “Davison patent”) which covers the Ethicon Prototype; (3) and European Patent No. 0 503 662.

The district court found that Ethicon had established a date of conception for the Ethicon Prototype earlier than Tyco’s January 1997 conception date for the claimed subject matter, and diligence towards reduction to practice that was constructively completed by patent application filings made in October 1997, which was after Tyco’s March 1997 reduction to practice.

The district court conducted a bench trial and determined that the Ethicon Prototype anticipated 26 of the asserted claims, but held that the Ethicon Prototype could not be relied on to establish obviousness because it was reduced to practice after Tyco’s reduction to practice. Without the Ethicon Prototype as prior art, the district court determined that the Curved Blade Claims and Dual Cam Claims were not invalid as obvious, and also determined that Ethicon infringed those claims.

The Federal Circuit Decision

The Federal Circuit decision was authored by Judge Prost and joined by Judges Reyna and Hughes.

The Federal Circuit noted that Ethicon can establish that the Ethicon Prototype qualifies as prior art under § 102(g) by establishing that “it reduced its invention to practice first or that it conceived of the invention first and was diligent in reducing it to practice.” The Federal Circuit found no error in the district court’s findings regarding Ethicon’s conception, reduction to practice, or diligence. Thus, the Federal Circuit affirmed the district court’s decision that the Ethicon Prototype qualified as prior art under under § 102(g), and affirmed the finding of anticipation on the merits.

With regard to obviousness, the Federal Circuit found that “[t]he district court improperly held that the Ethicon Prototype could not be considered prior art under § 103.”

The clear language of § 102(g) does not require prior reduction to practice so long as the inventor can prove that he or she conceived of the invention first and was diligent in later reducing it to practice. …. Here, the district court already determined that the Ethicon Prototype satisfied this statutory provision when it held that the prototype anticipates the other twenty-six asserted claims. ….


Furthermore, the clear language of § 102(g) and § 103 contains no requirement that a prior invention under § 102(g) be “known to the art” or the patentee at the time of invention to constitute prior art under § 103.

Thus, the Federal Circuit held that the Ethicon Prototype indeed qualified as prior art for obviousness purposes.

The Federal Circuit addressed the merits of the obviousness arguments, and found that the Curved Blade Claims and Dual Cam Claims were invalid as obvious.

[T]he Curved [Blade] Claims are invalid under § 103 because, in view of the Davison patent, it would have been obvious to one of ordinary skill to replace the straight blade of the Ethicon Prototype with a curved blade.


[T]he Dual Cam Claims are invalid under § 103 because it would have been obvious for a person of ordinary skill to modify the single cam of the Ethicon Prototype with the dual cam mechanism of the ’662 patent.

Having found all asserted claims invalid, the Federal Circuit vacated the damages award.

The Lingering Problem Of Secret Prior Art

In rendering its decision, the Federal Circuit acknowledged concerns about “secret prior art,” but referred to its statements in E.I. du Pont de Nemours &Co. v. Phillips Petroleum Co. (Fed. Cir. 1988) that “the requirement in § 102(g) that the prior invention not be abandoned, suppressed, or concealed after reduction to practice ‘does mollify somewhat the “secret” nature of § 102(g) prior art.’” The Federal Circuit also stated that the statute’s requirement that the invention not have been “abandoned, suppressed or concealed” after reduction to practice “sufficiently encourages public disclosure and aligns with the intent of our patent laws.”

I find it odd that the Federal Circuit felt the need to defend § 102(g) when Congress already has done away with it in the America Invents Act. On the other hand, this case may have some relevance under the AIA, which does leave in place one category of secret prior art– published patent applications that can be cited as prior art as of their effective filing dates. Following the analysis here, published patent applications that qualify as prior art under § 102(a)(2) could be cited in anticipation or obviousness rejections. This is an example of where the AIA did not go far enough to achieve international harmonization, as most other countries permit citation of such applications only if they destroy novelty.