112 and the Zone of Uncertainty

In consolidated cases Niazi Licensing Corp. v. Boston Scientific Corp. and Niazi Licensing Corp. v. St. Jude Medical S.C. Inc. the district court found U.S. Patent 6,638,268 (“the ‘268 patent”) to be invalid under 35 U.S.C. § 112 for being indefinite and not particularly pointing out and distinctly claiming the subject matter which the inventor regards as the invention. The indefiniteness determination for the ‘268 patent was arrived at by the Court during a Markman proceeding to interpret certain claim terms.

The independent claims of the ‘268 patent each recite an “inner, pliable catheter.” For example, representative claim 1 recites:

an inner, pliable catheter slidably disposed in the outer catheter and of greater length than the outer catheter so that a distal end portion of the inner catheter can be extended or retracted from a distal end opening of the outer catheter.

During the Markman proceeding the parties disputed the interpretation of the “inner, pliable catheter.” Niazi argued that the phrase should be construed to mean “a catheter that is easily bent, flexible.” Defendants Boston Scientific and St. Jude argued that the phrase was indefinite.

Niazi relied on McCreary v. United States, 35 Fed. Cl. 533, 556-57 (1996) to support their argument that “pliable” means “flexible.” In McCreary the court held the plain meaning of “flexiable” is “pliable.” However, the Court in the present case dismissed this argument as the dispute between Niazi and the Defendants was regarding how flexible or pliable the inner catheter must be to fall within the scope of the claims of the ‘268 patent.

To ascertain the degree of flexibility that falls within the scope of “pliable” the Court looked to the specification of the ‘268 patent. The specification provided various guidance, namely, that the inner catheter is “made of a soft, pliable material such as silicone,” is “extremely flexible,” and “preferably ha[s] a predetermined shape and a certain degree of stiff[n]ess to maintain such shape during manipulation in the heart, but still flexible enough to bend when required.” In light of this description, the Court found that the specification did not provide objective boundaries as to the range of pliability. Instead, the Court found that the specification creates a “zone of uncertainty” that an example included in the specification was insufficient to rectify as the specification did not provide objective factors on which a person of skill in the art could rely. The Court ultimately held that the independent claims were invalid as indefinite under Section 112.

Lessons for Practice

Terms of degree in patent claims can create tricky situations when construed. Perhaps the claims here may have survived if the specification provided more guidance as to what “degree of stiffness” is needed maintain shape “during manipulation in the heart” or as to what situations would require the inner catheter “to bend when required.” Perhaps the claims may have survived if the speciation appeared to be less contradictory when describing the degree of pliability, e.g., compare “extremely flexible” and “a certain degree of stiffness.” Perhaps the claims may have survived if the pliability of the inner catheter was tied to the stiffness of an outer catheter of the claims, e.g., the inner catheter is more flexible than the outer catheter. Ultimately, we will never know the answers to these question for this specific case. However, this case can be used as guidance when drafting patent claims and the associated specification. For example, when using terms of degree, drafting strategies such as claim diversity (e.g., claiming the stiffness with various strategies across different claims, including relative other claim elements), precision and consistency in the specification (e.g., avoiding hyperbolic terms such as “extremely”),  and providing an explanation of how a one skilled in the art would determine the scope of the terms of degree, may bolster a patent against Section 112 indefiniteness

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