Tuesday, November 21, 2006

Alternate Structures Leave Open the Possibility of Equivalents

Depuy Spine, Inc. v. Medtronic Sofamor, November 20, 2006 (05-1311)

This case revolved around pedicle screws and receiver members used in spinal surgeries. Pedicle screws are implanted into the vertebrae during surgery. The head of each pedicle screw is connected to a receiver portion, and a threaded rod connects the receiver portions of several screws. Together, the screws, receiver portions, and rods are used to stabilize spinal column segments.

Depuy appealed, among other things, the district court's grant of summary judgment that Medtronic's Vertex product did not infringe Depuy's U.S. Patent No. 5,207,678 literally or under the doctrine of equivalents.

On the issue of equivalents, the Federal Circuit considered whether Medtronic receiver's "cylindrical-conical shape" was equivalent to the '678 patent's "spherically shaped portion." Relying heavily on the "all elements" rule in Tronzo v. Biomet, Inc., 156 F.3d 1154 (Fed. Cir. 1998), the district court did not find a conical shape to be equivalent to a spherical shape without reading the limitation out of the claim, and that the Vertex model did not do "substantially the same thing" as the device in the ’678 patent.

The court noted that, as a practical matter, the "all elements" rule informs a doctrine of equivalents analysis by requiring that equivalence be assessed on a limitation-by-limitation basis, rather than from the perspective of the invention as a whole, and that no limitation be read completely out of the claim (i.e., "vitiated"). Thus, the "all elements" rule generally is not met—and therefore a claim limitation can be said to be vitiated—if the theory or evidence of equivalence is not able to establish that the differences between the limitation in the claim and the accused device are insubstantial.

In this case, the court found that there were sufficient questions of facts remaining between the two structures that precluded summary judgment:

We find no support in the present case for the district court’s conclusion that applying the doctrine of equivalents would vitiate or read out the "spherically-shaped" limitation. Our decision in Tronzo is factually distinguishable. In Tronzo, the invention related to artificial hip sockets and the patent at issue was a continuation-in-part. The independent claims that were added in the continuation covered a prosthesis socket with no specific shape. Because the written description only disclosed a conical shape for the prosthesis and characterized other shapes as "prior art" and "inferior" to a conical shape, we held that the independent claims were unsupported by the written description, not entitled to the parent’s filing date, and thus invalid in view of intervening prior art . . . The theory of equivalence, therefore, did not identify a specific element of the accused product as an equivalent to the "generally conical" limitation; rather, the patentee argued that any shape would be equivalent to a conical shape, despite clear indications in the written description to the contrary. We concluded that such a theory was insufficient as a matter of law and thus "would write the ‘generally conical outer surface’ limitation out the claims."

Here, unlike the patentee in Tronzo, DePuy did not propose that any shape would meet the "spherically-shaped" limitation. Rather, DePuy’s expert presented particularized declarations demonstrating its theory that a specific element of the accused device—the hollow conically-shaped portion of the receiver member—was insubstantially different from the corresponding "spherically-shaped" limitation because it supported the screw head, allowed for flexible movement, and—when the compression member is engaged—creates a rigid lock between the screw head and the receiver. Indeed, the expert expressly identified certain shapes that were different from the accused device but would not be capable of supporting the screw head, allowing flexible movement, and creating a rigid lock when the compression member is engaged. Also, unlike the patent at issue in Tronzo, the written description in the ’678 patent does not label other shapes as "prior art" and "inferior." Thus, unlike the theory presented in Tronzo, DePuy’s theory of equivalence was not improper.


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