# Words of Degree Are Not Automatically Indefinite: Niazi v. St. Jude Medical

> The Federal Circuit held that relative claim terms like resilient and pliable can be definite when the intrinsic record gives skilled readers reasonable certainty about their scope.

Topic: Patents  |  Author: Lidiia Levitska  |  Source: Intellectual Property Law (outsideipcounsel.com)
Canonical: https://outsideipcounsel.com/blog/niazi-v-st-jude-medical-relative-terms-definiteness/


Patent drafters reach constantly for words of degree—"resilient," "pliable," "substantially," "about"—because real inventions resist hard numerical boundaries. For years, accused infringers have argued that such language is fatally vague. In *Niazi Licensing Corp. v. St. Jude Medical S.C., Inc.*, 30 F.4th 1339 (Fed. Cir. 2022), the Federal Circuit pushed back, holding in an opinion by Judge Kara Stoll that relative terms are not automatically indefinite and that a patent's own disclosures can supply the certainty the statute demands. Decided April 11, 2022, the decision is a useful modern marker of how far the definiteness requirement does—and does not—reach.

## At a glance

- **Case:** *Niazi Licensing Corp. v. St. Jude Medical S.C., Inc.*, No. 2021-1864, 30 F.4th 1339 (Fed. Cir. Apr. 11, 2022).
- **Court:** U.S. Court of Appeals for the Federal Circuit; opinion by Judge Stoll, joined by Judges Taranto and Bryson, on appeal from the District of Minnesota.
- **Posture:** Appeal from a judgment holding all but one asserted claim of U.S. Patent No. 6,638,268 invalid as indefinite, plus evidentiary and sanctions rulings.
- **Holding:** The terms "resilient" and "pliable" are definite when read against the intrinsic evidence; the indefiniteness judgment is reversed, while the expert-exclusion and sanctions rulings and the no-infringement determination are affirmed.
- **Significance:** Confirmed that terms of degree are not inherently indefinite and clarified how the specification and dependent claims can rescue relative language under 35 U.S.C. 112.

## The double-catheter invention

The '268 patent claims a double catheter designed to cannulate the coronary sinus—threading a vein of the heart—without the significant manipulation older single catheters required, an advance relevant to treating congestive heart failure. The design pairs an outer catheter described as "resilient" with an inner catheter described as "pliable," so the stiffer outer member provides support and torque control while the softer inner member navigates delicate vessels. The District of Minnesota construed "resilient" and "pliable" as indefinite, reasoning that those relative terms gave no objective boundary, and on that basis held all but one of the asserted claims invalid. Because indefiniteness is a question the court resolves as a matter of law (informed by underlying facts), the ruling effectively gutted the patent before infringement was even reached.

## Terms of degree under Nautilus

The governing standard comes from 35 U.S.C. 112, as interpreted by the Supreme Court in *Nautilus, Inc. v. Biosig Instruments, Inc.* (2014): a claim is indefinite only if, read in light of the specification and prosecution history, it fails to inform skilled artisans "about the scope of the invention with reasonable certainty." Reasonable certainty, the Federal Circuit emphasized, is not absolute precision. Patent law "does not require absolute or mathematical precision," and the court has long accepted descriptive terms of degree so long as the intrinsic record supplies enough guidance. Judge Stoll framed the real problem with descriptive words not as their breadth—broad claims are a validity issue for other doctrines—but as whether the words leave a skilled reader genuinely unable to discern the claim's boundaries.

## Why "resilient" and "pliable" passed

Applying that standard, the panel found ample anchoring in the patent itself. For "resilient," dependent claims supplied concrete examples of qualifying materials—such as "braided silastic"—and the written description explained that the outer catheter has a "braided design" providing "torque control and resistance," giving skilled readers a recognizable class of structures. For "pliable," the specification identified silicone as a suitable soft material for the inner catheter and explained that the inner catheter "has no longitudinal braiding, which makes it extremely flexible and able to conform to various shapes." Read together, the intrinsic evidence let a person of ordinary skill understand which catheters were resilient (stiffer, braided, supportive) and which were pliable (softer, unbraided, conforming) with reasonable certainty. The court therefore reversed the indefiniteness holding and revived the claims.

## A mixed result

The reversal on definiteness did not hand Niazi a victory. The Federal Circuit affirmed the district court's evidentiary sanctions, which excluded portions of Niazi's expert reports because the patentee had failed to disclose predicate facts during discovery, and affirmed the exclusion of part of the damages report as unreliable, along with monetary sanctions covering costs and fees tied to a motion to strike. The court also disagreed with some of the district court's claim constructions but agreed with others and, crucially, agreed that Niazi had not met its burden to prove direct infringement—affirming the no-infringement judgment without needing to reach inducement. The lesson cuts two ways: careful drafting can defeat an indefiniteness attack, but litigation discipline in discovery and proof still decides who wins.

## Open questions

- **How much intrinsic support is enough?** Niazi had dependent claims and specific material examples; the opinion leaves unclear how thin the disclosure can become before a term of degree tips into indefiniteness.
- **What about terms with no exemplary structures?** The decision turned partly on concrete examples like silastic and silicone; relative terms unmoored from any disclosed embodiment remain riskier.
- **Where is the line between breadth and indefiniteness?** The court insisted breadth alone is not the problem, but broad functional language continues to draw scrutiny under both Section 112 and eligibility doctrines.

## Implications

- **For patent drafters:** Pair relative terms with concrete examples, material lists, and explanatory passages in the specification; dependent claims that name qualifying structures can be decisive evidence of definiteness.
- **For accused infringers:** An indefiniteness defense aimed at a single descriptive word is weak when the specification explains the term; aim instead at terms genuinely unsupported by the intrinsic record.
- **For litigators:** Discovery compliance matters as much as claim drafting—Niazi salvaged its claims but lost on infringement partly because key expert evidence was excluded as a sanction.
- **For licensors and portfolio owners:** Terms of degree remain usable and enforceable, but their durability depends on the quality of the written description supporting them.
- **For trial courts:** Definiteness must be assessed against the full intrinsic record, not by isolating a relative word and declaring it boundless.

## Frequently asked questions

**Does using a relative term like resilient make a patent claim indefinite?**
No. The Federal Circuit confirmed that terms of degree are not inherently indefinite. A claim is invalid for indefiniteness only if, read in light of the specification and prosecution history, it fails to inform a skilled person about the scope of the invention with reasonable certainty.

**What is the legal standard for definiteness?**
Under 35 U.S.C. 112 and the Supreme Court's 2014 Nautilus decision, a claim must inform those skilled in the art about the scope of the invention with reasonable certainty when read in light of the specification and prosecution history. Some uncertainty is tolerated; absolute precision is not required.

**Did Niazi ultimately win the case?**
Only in part. The Federal Circuit reversed the indefiniteness ruling and revived most of the claims, but it affirmed the exclusion of portions of Niazi's expert reports as a discovery sanction and affirmed that Niazi had failed to prove infringement, so the patent owner did not prevail on the merits.

## Authorities and sources

- *Niazi Licensing Corp. v. St. Jude Medical S.C., Inc.*, No. 2021-1864 (Fed. Cir. Apr. 11, 2022) (Justia): https://law.justia.com/cases/federal/appellate-courts/cafc/21-1864/21-1864-2022-04-11.html
- Federal Circuit slip opinion (court PDF): https://www.cafc.uscourts.gov/opinions-orders/21-1864.OPINION.4-11-2022_1934126.pdf
- Definiteness requirement, 35 U.S.C. 112 (Cornell LII): https://www.law.cornell.edu/uscode/text/35/112
- *Nautilus, Inc. v. Biosig Instruments, Inc.*, 572 U.S. 898 (2014) (Justia): https://supreme.justia.com/cases/federal/us/572/898/