The RE'119 patent claims a method and a pacemaker apparatus. Both relate to a "procedure for pacing of the heart in a particular way so as to improve its contraction pattern, and thereby augment the movement of blood through the heart."

Mirowski Family Ventures L.L.C. and Eli Lilly are, respectively, the assignee and exclusive licensee of the patent. Guidant Corporation is a medical device manufacturer that was formed in 1994 when Eli Lilly divested certain assets, while Guidant Sales Corporation is a wholly owned subsidiary of Guidant Corporation. For ease of reference, we refer to the four defendants as "Guidant."

In the action, Medtronic alleged that claims 15-26 of U.S. Reissue Patent No. 38,119 ("the RE'119 patent"), a re-issue of U.S. Patent No. 4,928,688 ("the '688 patent"), are invalid by reason of violation of the rule against recapturing surrendered subject matter.

Medtronic now appeals from the final judgment of the district court, following a bench trial, that the RE'119 patent is not invalid. See Medtronic, Inc. v. Guidant Corp., 378 F. Supp. 2d 503 (D. Del. 2005). We affirm.

For cogency, focusing on subject matter recapture during reissue, skirting the technical arguments in this case.

Pursuant to 35 U.S.C. § 251, a patentee may obtain reissue of a patent if the patent is, through error "without any deceptive intention, deemed wholly or partly inoperative or invalid, . . . by reason of the patentee claiming more or less than he had a right to claim in the patent . . . ." 35 U.S.C. § 251; see also 37 C.F.R. § 1.175. "In considering the 'error' requirement, we keep in mind that the reissue statute is 'based on fundamental principles of equity and fairness, and should be construed liberally.'" Hester Indus., Inc. v. Stein, Inc., 142 F.3d 1472, 1479 (Fed. Cir. 1998) (citation omitted). We have stated that "[a]n attorney's failure to appreciate the full scope of the invention is one of the most common sources of defects in patents," and is generally sufficient to justify reissuing a patent. In re Wilder, 736 F.2d 1516, 1519 (Fed. Cir. 1984); see also Hester, 142 F.3d at 1479-80; In re Clement, 131 F.3d 1464, 1468 (Fed. Cir. 1997); Mentor Corp. v. Coloplast, Inc., 998 F.2d 992, 995 (Fed. Cir. 1993); Scripps Clinic & Res. Found. v. Genentech, Inc., 927 F.2d 1565, 1575 (Fed. Cir. 1991). It is not necessary that the error be unavoidable or that the error could not have been discovered by the patentee through proper communication with the prosecuting attorney. Wilder, 736 F.2d at 1519.

Reissue proceedings, however, cannot be used to obtain subject matter that could not have been included in the original patent. Under the "recapture" rule, the deliberate surrender of a claim to certain subject matter during the original prosecution of the application for a patent "made in an effort to overcome a prior art rejection" is not such "error" as will allow the patentee to recapture that subject matter in a reissue. Clement, 131 F.3d at 1468-69. Thus, the recapture rule prevents a patentee from regaining, through reissue, subject matter that was surrendered during prosecution of the original patent in an effort to obtain allowance of the original claims. Pannu v. Storz Inst., Inc., 258 F.3d 1366, 1371 (Fed. Cir. 2001); see also Hester, 142 F.3d at 1479-80 ("[A] surrender is not the type of correctable 'error' contemplated by the reissue statute.").

[I]f the claims of a reissue patent violate the recapture rule, the claims are invalid, see N. Am. Container, 415 F.3d at 1349... A surrender can occur by argument as well as by amendment. Hester, 142 F.3d at 1480-84 (noting the statement in Clement that "'[t]o determine whether an applicant surrendered particular subject matter, we look to the prosecution history for arguments and changes to the claims made in an effort to overcome a prior art rejection'" (quoting Clement, 131 F.3d at 1469) (emphasis added in Hester, 142 F.3d at 1480)). We stated in Hester that, like prosecution history estoppel, "unmistakable assertions made to the Patent Office in support of patentability" "can give rise to a surrender for purposes of the recapture rule." Id. at 1482.

"We apply the recapture rule as a three-step process: (1) first, we determine whether, and in what respect, the reissue claims are broader in scope than the original patent claims; (2) next, we determine whether the broader aspects of the reissue claims relate to subject matter surrendered in the original prosecution; and (3) finally, we determine whether the reissue claims were materially narrowed in other respects, so that the claims may not have been enlarged, and hence avoid the recapture rule." N. Am. Container, Inc. v. Plastipak Packaging, Inc., 415 F.3d 1335, 1349 (Fed. Cir. 2005) (citing Clement, 131 F.3d at 1471); see also Pannu, 258 F.3d at 1371 (citing Hester, 142 F.3d at 1482-83; Clement, 131 F.3d at 1470).

Determining whether the claims of a reissued patent violate 35 U.S.C. § 251 is a question of law, which we review de novo. Pannu, 258 F.3d at 1370. The legal conclusion of whether an applicant has met the statutory requirements of 35 U.S.C. § 251 is based on underlying findings of fact, which we sustain unless they are clearly erroneous. Clement, 131 F.3d at 1468.

"Whether amendments made during reexamination enlarge the scope of a claim is a matter of claim construction." Hockerson-Halberstadt, Inc. v. Converse Inc., 183 F.3d 1369, 1373 (Fed. Cir. 1999). "'A claim of a reissue application is broader in scope than the original claims if it contains within its scope any conceivable apparatus or process which would not have infringed the original patent. A reissue claim that is broader in any respect is considered to be broader than the original claims even though it may be narrower in other respects.'" Id. at 1374 (quoting Tillotson, Ltd. v. Walbro Corp., 831 F.2d 1033, 1037 n.2 (Fed. Cir. 1987)); see also Pannu, 258 F.3d at 1371 (stating that a reissue claim that does not include a limitation present in the original claims is broader than the original claim).