Opinion ID: 211654
Heading Depth: 4
Heading Rank: 1

Heading: anchoring means

Text: 34 The limitation recites the word means, which gives rise to the presumption that § 112, ¶ 6 applies. See Rodime PLC v. Seagate Tech., Inc., 174 F.3d 1294, 1302 (Fed.Cir.1999). The claimed function of the anchoring means is to secure said anchors to said bone segment. '555 patent, col. 8, ll. 38-39. No structure is recited in the claim to perform this function. See id., ll. 35-56. Thus, § 112, ¶ 6 applies and the claim shall be construed to cover the corresponding structure ... described in the specification and equivalents thereof. 35 U.S.C. § 112, ¶ 6 (2000); Al-Site Corp. v. VSI Int'l, Inc., 174 F.3d 1308, 1320 (Fed.Cir.1999). 35 The specification discloses only one embodiment. That embodiment contains a screw which carries a separate anchor such that when the screw 21 engages the anchor seat 23, a limited ball-and-socket joint is formed which permits freedom of movement between the rod support 23 and the screw 21. '555 patent, col. 5, ll. 4-47. The specification unambiguously states that a feature of the present invention is that [e]ach anchor seat is secured by a cancellous screw which cooperates through a sloped bore in the anchor seat so as to provide a limited ball and socket motion. Id., col. 1, l. 65-col. 2, l. 21. It continues: 36 The present invention utilizes a rod and vertebral anchors which holds [sic] the rod in position. Each anchor is secured to the vertebrae by a transpedicular screw member. 37 .... 38 ... [T]he present design utilizes two implant sets on either side of the spinous processes. Each implant set includes a ... rod .... Generally, an implant set is used on each side of the spinous process .... The rod is held in position by a stainless steel vertebral anchor which captures the rods. The anchor has a seat member which is secured to the vertebrae by a stainless steel transpedicular screw. The screw is separate from the anchor seat and thus provides for limited motion between the anchor seat and the vertebrae. 39 Id., col. 3, ll. 26-67 (emphasis added). The patent discloses no other structure for securing the anchor to the bone. The patent states that the polyaxial design acts as a `shock-absorber' to prevent direct transfer of load from the rod to the bone-screw interface prior to achieving bony fusion, thereby decreasing the chance of failure. Id., ll. 63-67. Thus, the district court was correct both in linking the recited function to the structure disclosed in the specification and in concluding that the corresponding structure was polyaxial. Medtronic argues that even if the limitation is a means-plus-function limitation linked to the disclosed polyaxial structure, the claim nonetheless should be construed to include alternative structures like monoaxial screws. However, because there is only one embodiment described in the specification to secure the anchor to the bone — a polyaxial screw and anchor structure — there is no basis on which to extend the limitation to cover alternative, non-disclosed structure not shown to be structurally equivalent. See 35 U.S.C. § 112, ¶ 6; Al-Site, 174 F.3d at 1320. 40 We reject the parties' remaining arguments. First, although the doctrine of claim differentiation suggests that claim 5 should be broader than claim 1, any presumption that the claims differ with respect to this feature may be overcome by a contrary construction mandated by the application of § 112, ¶ 6. See Laitram Corp. v. Rexnord, Inc., 939 F.2d 1533, 1538 (Fed.Cir.1991) (holding that the doctrine of claim differentiation yields to an interpretation mandated by § 112, ¶ 6). Second, Medtronic's assertion that marking estoppel applies is incorrect. Even if Cross Medical marked monoaxial screws with the '555 patent number, such evidence conflicts with the intrinsic record and has no bearing on our construction. See Phillips, 415 F.3d at 1318 ([A] court should discount [extrinsic evidence] that is clearly at odds with the claim construction mandated by the claims themselves, the written description, and the prosecution history, in other words, with the written record of the patent. (internal quotation omitted)); cf. SmithKline Diagnostics v. Helena Labs. Corp., 859 F.2d 878, 890-91 (Fed.Cir.1988) (holding that an accused infringer's mis-marking of a product could not convert by estoppel an admittedly non-infringing product into an infringing product). Finally, Cross Medical's argument that we should consider the validity of claim 5 in construing the limitation misses the mark. Because the other claim construction tools unambiguously resolve the claim construction dispute, considering validity would be improper. Phillips, 415 F.3d at 1327 ([W]e have limited the maxim [of construing a claim to preserve its validity] to cases in which `the court concludes, after applying all the available tools of claim construction, that the claim is still ambiguous.'). 41