Applying the doctrine of equivalents with the "all elements rule," the U.S. Court of Appeals for the Federal Circuit, inter alia, found that a district court had erroneously concluded that there was no question of fact as to whether a cylindrical-conical shape could be equivalent to a spherically-shaped element claimed in a patent for surgical screws and reversed a grant of summary judgment that had found no infringement. DePuy Spine, Inc. v. Medtronic Sofamor Danek, Inc., Case Nos. 05-1311, -1335 (Fed. Cir., Nov.20, 2006) (Linn, J.).
Depuy’s U.S. Patent No. 5,207,678 (the ’578 patent) relates to pedicle screws and receiver members used in spinal surgeries. To stabilize the spinal column, the pedicle screws are implanted in the spine, the head of each pedicle screw is connected to a receiver portion and a threaded rod connects the receiver portions of several screws. At issue was whether Medtronic’s products infringed Depuy’s patent for pedicle screws, used to stabilize spinal column segments during surgery.
Relying on Federal Circuit precedent in Tronzo, the district court adopted Medtronic’s argument that a conically-shaped portion of Medtronic’s spinal implant screws could not infringe a "spherically-shaped" limitation without reading the limitation out of the claims.
The Federal Circuit disagreed with the lower court’s application of the "all elements" rule. The Court explained that "the all elements rule generally is not met" if the theory or evidence of equivalence is insufficient to establish that the differences between the limitation in the claim and the accused device are insubstantial. The Court noted that "[a] holding that the doctrine of equivalents cannot be applied to an accused device because it ‘vitiates’ a claim limitation is nothing more than a conclusion that the evidence is such that no reasonable jury could conclude that an element of an accused device is equivalent to an element called for in the claim, or that the theory of equivalence ... otherwise lacks legal sufficiency." The Court distinguished its finding of vitiation in Tronzo based on the type of argument made by the patent holder. In Tronzo decision, the patentee’s theory of equivalence was that any shape would be equivalent to the conical limitation (contrary to clear indications in the written description). DePuy’s experts, on the other hand, had identified shapes that would not have been equivalent and presented particularized declarations demonstrating that a specific element of Medtronic’s device was insubstantially different from the corresponding limitation. Finding that a reasonable jury could therefore find the devices equivalent, the Federal Circuit found DePuy’s theories to be legally sufficient and reversed the district court’s summary judgment of non-infringement under the doctrine of equivalents. Other issues addressed in this decision include the construction of particular claim limitations and a negative means-plus-function argument.
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