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Corresponding Structure for Means-Plus-Function Claim Must Be “Clearly Linked” to Function

April 20, 2001
Lehman, Christine E.

Decision icon Decision

Last Month at the Federal Circuit - May 2001

Judges: Linn (author), Michel, and Dyk

In Medtronic, Inc. v. Advanced Cardiovascular Systems, Inc., No. 00-1205 (Fed. Cir. Apr. 20, 2001), the Federal Circuit affirmed a district court’s construction of the claim limitation “means for connecting adjacent elements together,” to which Medtronic, Inc. (“Medtronic”) had conceded no infringement. The Federal Circuit found the corresponding structure in the specification, a helical coil, to be the only structure that was clearly linked or associated with the stated function. Additional disclosed structure, straight wires and hooks, also performed the stated function, but was not clearly linked or associated with the claimed function and, thus, was not corresponding structure for purposes of the claim construction.

U.S. Patent No. 5,653,727 (“the ‘727 patent”) is directed to a stent for enlarging the inside of an artery. The ‘727 patent specifically discloses and describes a helically wound, continuous-wire stent with the overall appearance of a coiled wire. The specification describes the stent as containing a series of successive 360° windings. The specification also discloses the use of straight wires and hooks to prevent longitudinal overstretch of the stent by connecting coils along the length of the stent to prevent the distance between the coils from becoming greater. The accused stent was designed with loops, and the parties agreed it was not helically wound.

In construing the disputed claim limitation, “means for connecting adjacent elements together,” the Federal Circuit looked to the specification in accordance with 35 U.S.C. § 112, ¶ 6, to find the structure corresponding to the function of “connecting adjacent elements together.” The parties did not dispute that the helical windings of the stent were corresponding structure, in that the successive coils of the helical stent were inherently connected to each other by the coiled wire. However, Medtronic argued that the straight wire and hooks described in the specification were also corresponding structure.

The Federal Circuit agreed that the straight wires and hooks were capable of performing the claimed function, but held that the straight wires and hooks were not clearly linked or associated in the specification with the function of connecting the adjacent elements together. The description in the specification about the use of wires and hooks related specifically to the function of preventing overstretch of the formed helical coil, not to connecting separate elements. The coils of the stent were already inherently connected to each other, being formed of a continuous wire, and, therefore, the wires or hooks were not described in the specification as performing the function of connecting the coils. The Court also looked to the prosecution history, but found no link or association between the function and the wires and hooks.

Medtronic had conceded that under the claim construction limited to the helical coil there could be no infringement. Therefore, the Federal Circuit affirmed the district court’s judgment of noninfringement.