Federal Circuit Provides Additional Guidance for Claim Construction and Analysis of Mixed Method, Apparatus Claims

Posted by Jessica Chao on Jan 4, 2017

In LifeNet Health v. LifeCell Corp., the Federal Circuit reiterated the importance of properly preserving claim construction issues for appeal and providing specific support for claim terms and specification terms in a patent application’s written description to achieve more reasoned claim construction.

What This Means to You

  • Litigants should be mindful to raise specific claim construction disputes before and during trial in order to preserve the dispute for appeal.
  • Functional limitations defined in the negative should define a property of the recited apparatus to avoid indefiniteness for mixing method steps in an apparatus claim.
  • Claim terms should be broadly defined in the specification, include multiple embodiments and ranges for the invention, and avoid limiting language like “present invention” and “preferably” to avoid restrictive claim construction under Phillips v. AWH Corp.

Case Background

LifeNet sued LifeCell, alleging that LifeCell’s sales of plasticized soft tissue grafts for medical, orthopedic, dental, and cosmetic surgery transplants infringed its U.S. Patent No. 6,569,200 (claims 1-4, 7, 8, and 10). Claims 1-4 are apparatus claims directed to plasticized soft tissue grafts, and claims 7, 8, and 10 are claims directed to methods of producing plasticized soft tissue grafts.

Following claim construction and trial, a jury found LifeNet’s patent infringed by LifeCell and not invalid. The district court entered final judgment consistent with the jury’s findings, and the Federal Circuit affirmed. On appeal, the Federal Circuit addressed, inter alia, three key issues: 1) the claim construction of the term “plasticizers not removed”; 2) whether an apparatus claim that includes method steps is indefinite under 35 U.S.C. § 112, paragraph 2; and 3) the claim construction of the term “plasticized soft tissue graft.”

Decision Analysis

On the first issue, LifeCell argued that the district court erred by allowing the jury to decide a claim construction dispute—namely, the proper scope of the term “said one or more plasticizers are not removed from [an] internal matrix of [the] plasticized soft tissue graft” (the “non-removal limitation”). According to LifeCell, under O2 Micro, the court, not the jury, must resolve an actual dispute regarding the proper scope of a claim term. During claim construction, the parties’ dispute over the non-removal limitation centered on the degree of plasticizer removal—i.e., how much, if any, plasticizer is to be removed from the claimed tissue grafts. The district court determined that construction of the entire term was unnecessary, observing that a person of ordinary skill in the art would understand the phrase “not removed” to mean that no plasticizers are removed prior to transplantation.

On appeal, however, LifeCell focused its non-infringement arguments not only on the degree of non-removal required, but also from where those plasticizers are not to be removed. Particularly as to the latter argument, the court observed that LifeCell did not request modification of the district court’s claim construction in a timely manner, and presented the issue as a factual one before, during, and after trial. As the court noted, there is not necessarily an O2 Micro issue whenever further claim construction could resolve the parties’ dispute. Based on the record before the court, LifeCell’s discontent with the claim constructions of certain terms was not sufficient to give rise to an O2 Micro violation.

On the second issue, the Federal Circuit upheld the district court’s finding that the asserted claims were not invalid under 35 U.S.C. § 112, paragraph 2 as indefinite for including method steps of using an apparatus in an apparatus claim. LifeCell argued that because the non-removal limitation describes a method for use in the asserted apparatus claims, those claims are indefinite for covering both an apparatus and a method of using that apparatus. The court disagreed, however, reasoning that the non-removal limitation defines a property of the recited plasticizer, rather than a method step. According to the court, functional limitations recited in the negative may describe a capability or structural element, and, thus, do not render an apparatus claim invalid as indefinite.

Finally, on the last issue, LifeCell argued that the district court erred in its construction of the term “plasticized soft tissue graft” by failing to also require that the tissue graft be “dehydrated” in a particular manner. The Federal Circuit agreed with LifeNet, however, and ultimately favored a broader interpretation for construction of “plasticized soft tissue graft.” The court found that while the word “dehydrated” is used often in the specification, it is used broadly, and is not confined to the single embodiment in the specification without a specific indication that the patentee intended for the claims to be limited to specific embodiments in the specification.


There can be value in seeking clarification or modification of a district court’s claim construction of a disputed claim term if there appear to be unresolved interpretation issues material to the outcome. Failure to do so may prevent a litigant from advancing or maintaining a new (or more nuanced) claim construction argument on appeal, and from raising certain evidentiary challenges or non-infringement arguments based on that new construction.

Further, while functional limitations in apparatus claims may avoid indefiniteness by defining a property of the recited apparatus, patent applicants generally should avoid including method steps or ambiguous contextual language in an apparatus claim absent countervailing reasons why doing so would add value. Patent applicants should, however, draft express specification support for preferred claim construction and broadly define claim terms in the specification.

Wolf Greenfield's CAFC Blog

Here, Wolf Greenfield attorneys summarize and identify key takeaways from recent patent law cases decided by the U.S. Court of Appeals for the Federal Circuit. View past case summaries here.

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This blog is intended to promote thought and debate on developing areas of the law. The opinions, commentary and characterizations of cases provided on this blog are not legal advice and do not represent the opinions of Wolf Greenfield or its clients.