US 5562720

I'll verify this patent against live sources, including any 2026 litigation activity.

Let me check for litigation activity and pull the exact claim text.

Let me retrieve the exact claims text and check for any 2026 litigation.

US Patent 5,562,720 — Verified Summary

Note on sources: I verified this against the full patent text you supplied (fetched from https://patents.google.com/patent/[US5562720](/patent/US5562720)/en), the USPTO/Google Patent PDF (http://patentimages.storage.googleapis.com/42/7e/63/6b94e8b0399b7f/US5562720.pdf), and live search results. Where a source conflicts with my training data, I've deferred to the retrieved text.

Bibliographic Data

Assignment chain (from the Google Patents record): Vesta Medical, Inc. (filed 1994; formal assignment recorded Feb. 10, 1995) → Sherwood Services AG (assigned June 1, 1999) → Tyco Healthcare Group AG (merger Sept. 21, 2010) → Covidien AG (change of name Sept. 21, 2010).

Continuation-in-part relationships (from the patent's CROSS-REFERENCE section): This is a CIP of:

• Ser. No. 07/877,567, filed May 1, 1992 → now US 5,277,201
• Ser. No. 08/046,683, filed Apr. 14, 1993 → now US 5,443,470
• Ser. No. 08/106,601, filed Aug. 16, 1993 → now US 5,443,463
• Ser. No. 08/136,098, filed Oct. 14, 1993 → now abandoned

Minor discrepancy noted: Google Patents lists the priority date as 1992-05-01 (matching the CIP text), while Unified Patents' portal page lists 1992-04-30 for the same document. I'm flagging this rather than resolving it.

Abstract (verbatim from the patent)

"An endometrial ablation device and a method of manufacturing and using the device. An RF current is passed through an endometrium to heat it. An electroconductive expandable member such as a balloon is used as the medium for passing the current and causing the heating of the endometrium. The power delivered from a power source to the balloon is selectively provided to a plurality of electrode area segments on the balloon with each of the segments have a thermistor associated with it whereby temperature is monitored and controlled by a feedback arrangement from the thermistors. The selective application of power is provided on the basis of a switching arrangement which provides either monopolar or bipolar energy to the electrodes. The method of manufacturing the ablation device includes using commercially available stretchable sheet material or providing a mandrel or support base and coating the mandrel or base with an uncured emulsion. The emulsion is then cured to form a bladder-like coating. The coating is thereafter removed from the mandrel or base to form a bladder. Electrons and temperature sensors are formed on or secured to the bladder during or after the curing process and a fluid delivery tube is secured to the bladder for inflating the bladder."

Literal-text note: The abstract says "Electrons and temperature sensors are formed on or secured to the bladder." Read literally as written in the source; it clearly functions as "electrodes" in context, but I am not correcting it per the strict-identifier rule.

Independent Claims — Plain-Language Overview

The patent contains 4 claims total: two independent claims (one apparatus, one method) and one dependent claim each. The claim language closely tracks the "Objects and Summary of the Invention" section, quoted below.

Claim 1 — Apparatus (independent)
An apparatus for selectively applying RF energy to a body organ, comprising three cooperating elements:

1. Electrode means for making electrical contact with the organ's tissue;
2. RF power means that selectively supplies current to the electrodes at a frequency greater than 250 kHz, to heat the tissue at a uniform temperature between 45 °C and 90 °C; and
3. Switching means receiving the RF output and controllably delivering power to the electrodes, where the switching means includes (a) a first means for providing bipolar energy, (b) a second means for providing monopolar energy, and (c) a third means for selecting between the bipolar and monopolar means.

Plain language: A tissue-ablation machine that can operate in either bipolar or monopolar RF mode, with a selector switch letting the operator choose. This is the claim that gives the patent its title.

Claim 2 — Dependent on Claim 1
The apparatus of claim 1, wherein the first (bipolar) means includes means for delivering RF energy in a bipolar mode between selected ones of a plurality of electrodes — i.e., the operator can pick which electrode pairs act as active/return.

Claim 3 — Method (independent)
A method of heating body-organ tissue by selective application of RF energy, comprising:

1. Providing a plurality of electrodes in electrical contact with the organ;
2. Providing a source of RF energy to the electrodes; and
3. Controlling the RF energy to provide for one of bipolar and monopolar application of energy to the electrodes.

Plain language: The method counterpart — place multiple electrodes against tissue, hook up RF, and controllably run it either bipolar or monopolar.

Claim 4 — Dependent on Claim 3
The method of claim 3, wherein the controlling step includes selectively providing bipolar energy to selective pairs of the plurality of electrodes.

Confidence note: I have high confidence in the substance and structure of these four claims (the patent record confirms "4 Claims," and the Summary-of-Invention paragraphs are conventionally near-verbatim claim text). However, I could not independently retrieve the verbatim issued claim language from the claim columns in this session — the excerpts returned were from the summary section. Treat the exact wording above as a faithful paraphrase of the claim set, not a certified verbatim reproduction.

Litigation / CAFC 2026 Search Result

No CAFC 2026 docket involving US 5,562,720 was found. I searched for 2026 Federal Circuit activity tied to this number and returned only an unrelated case (FedEx Corp. v. Qualcomm Inc., Fed. Cir. No. 24-1235, decided April 29, 2026 — an IPR obviousness appeal concerning RFID "programming change" claim construction). That case does not involve this patent.

This is consistent with the patent's expired status (expiration October 8, 2013), which makes live infringement litigation improbable.

One relevant finding, distinguishable: US 5,562,720 ("Stern") appears in USPTO PTAB/patent-center petition papers as prior art — e.g., PTAB petitions 1555012 and 1555015 (PTACTS), where "Ex.1033-Stern" is cited and discussed at length (e.g., Stern's FIG. 15 switch matrix and FIGS. 17–19 bipolar electrode pairs) in obviousness challenges to other patents (involving Edwards-'535). In those papers, 5,562,720 is a cited reference, not the challenged or asserted patent. If you are looking for 2026 contentious activity, that is the only place this number surfaces — as an anticipatory/obviousness reference.

Uncertainty: I could not confirm the exact issuing entity/case numbers of those PTAB petitions from the search snippets alone, and I found no district-court docket or CAFC appeal naming 5,562,720 as an asserted patent. If you need the precise PTAB proceeding numbers and the patents under challenge, that would require a direct PACER/PTAB API lookup, which I did not have confirmed access to here.

I'll search for litigation involving US patent 5562720 across the specified sources.

Let me search more targeted sources for litigation.

Summary Finding

Based on my searches, I found no litigation (no district court action, ITC investigation, or Federal Circuit appeal) in which US Patent 5,562,720 was asserted or challenged. I also found no PTAB post-grant proceedings (IPR/PGR/CBM) against the patent.

I want to be explicit about the limits of this conclusion: the searches I ran surfaced only bibliographic, patent-family, prior-art-citation, and USPTO assignment records — not litigation records. I was not able to specifically confirm this through the Unified Patents litigation case list, PACER, or the CAFC docket, because those sites are not directly indexed/reachable in the results returned. So this is a "nothing found" result, not a verified negative clearance. A definitive answer would require a direct Docket Navigator / Lex Machina / PACER query on the patent number and its assignees.

What the searches did return (context, not litigation)

The hits mentioning "5562720" fell into these categories:

1. Patent family / prosecution records — US 5,562,720 is a continuation-in-part of Ser. Nos. 07/877,567 (now US 5,277,201), 08/046,683 (US 5,443,470), 08/106,601 (US 5,443,463), and 08/136,098 (abandoned). Family members include EP 0723467, AU 679271, CA 2173851, JP 9503689, WO 95/10326, US 5,643,304, etc.

2. Prior-art citations — The patent is cited as prior art in other cases/patents (e.g., WO 2003/051214 and EP 1 003 432), which is expected for a 1996 patent and is unrelated to any dispute.

3. USPTO assignment records — Original assignee Vesta Medical, Inc. (Palo Alto); later assigned to Sherwood Services AG (1999), then Tyco Healthcare Group AG, and ultimately Covidien AG. The Google Patents record lists legal status as "Expired – Lifetime," with an anticipated expiration of 2013-10-08.

4. Unrelated litigation noise (do not attribute to '720):

   • Janssen Biotech, Inc. v. Celltrion Healthcare Co., Ltd., No. 2017-1120 (Fed. Cir.) — the "'272 patent" there is US 5,569,272, an antibody patent, not 5,562,720.
   • Intuitive Surgical / IBM v. Computer Motion — involves unrelated patents (e.g., 5,878,193; 5,907,664; 6,201,984).
   • Various Blackbird Technologies and John Deere cases — unrelated patents.

Why the absence of litigation is plausible

• The patent expired on October 8, 2013 (20 years from the Oct. 6, 1994 filing, adjusted by the pre-URAA term rules/parent priority). Damages windows for asserting it have long closed.
• Its assignee chain consolidates into Covidien AG, and the underlying Vesta Medical endometrial-ablation technology was commercialized within the Covidien/Valleylab electrosurgical portfolio rather than litigated. Notably, the sibling patents in the same family do not appear in any reported enforcement campaigns either.

Bottom line

No known litigation involves US Patent 5,562,720. If you need a litigation-grade negative finding, the recommended next step is a direct paid docket search (Docket Navigator, Lex Machina, or PACER's full-text search for "5,562,720" and "5562720") plus a CAFC docket query, since I could not reach those databases directly in this session.

I'll start by verifying the structured-data signal (no AIA proceedings on file) against public sources, and check related patents in the same family.

Proceedings overview

Zero AIA trial proceedings are on file for US 5,562,720 — the structured USPTO ODP record returns no IPR, PGR, or CBM, and my independent search of PTAB E2E petition documents, PTAB statistics, and the patent's own family/prosecution record surfaced no petition ever filed against it. Breakdown by status is therefore 0 active / 0 claims invalidated / 0 claims sustained / 0 settled / 0 institution denials — but the defensive posture is not "hardened patent"; it is "dead patent." The '720 patent' s own front-page record shows an anticipated expiration of 2013-10-08 with legal status "Expired - Lifetime." No IPR was ever filed because by the time the AIA IPR regime matured (2012-2014), the patent had months of life left and no damages runway worth a petition fee. If you receive a demand letter citing the '720 patent today, your first response is not an invalidity defense — it is the expiration date.

Proceedings

No proceeding numbers exist to report. I will not manufacture any. The per-proceeding template is inapplicable; below are the specific negative findings and the near-misses I checked so you can audit the conclusion.

Adjacent-field caveat (do not confuse these): The uterine-ablation space has seen heavy PTAB activity — most notably the Hologic/Cytyc v. Minerva Surgical war over the "Moisture Transport" contact-electrocoagulation family, where Minerva's petition on Hologic's '183 patent was instituted 2016-10-06, produced a Final Written Decision on 2017-12-15 invalidating all claims, and was affirmed by the Federal Circuit on 2019-04-19 (per Hologic's public 10-Q disclosures). I could not confirm the specific IPR number for that '183 trial from the sources retrieved, so I am deliberately not stating one. That litigation concerns Hologic's 1998-priority family, not the Vesta/Covidien '720 family, and it tells you nothing about the validity of the '720 claims.

Strategic summary

Claim status on US 5,562,720: every claim is UNTESTED at the PTAB — and every claim is expired. There are no canceled claims, no sustained claims, and no claim-level PTAB rulings to cite. The claim set (which, per the specification, includes apparatus claims directed to an expandable bladder with at least one electrode and a fluid delivery tube, and method claims directed to selectively applying bipolar or monopolar RF energy to a plurality of electrodes, plus manufacturing claims) was never narrowed by the Board. Whether that is good news for a defendant depends entirely on the calendar: the patent issued 1996-10-08 from a 1994-10-06 filing as a CIP, traces priority to 1992-05-01, and reached its anticipated expiration on 2013-10-08. Post-expiration infringement is legally impossible, and the § 286 six-year back-damages window for pre-expiration conduct closed around 2019-10-08. A patent owner asserting this patent in 2026 is asserting a claim that cannot reach conduct occurring in the last ~13 years.

Estoppel landscape: § 315(e)(2) is a non-issue. Estoppel attaches only to a petitioner whose IPR was instituted and reached a final written decision. With no institution, no petitioner is estopped, no prior art is foreclosed, and — more importantly — no defensive value has been banked by anyone. There is therefore also no pre-packaged invalidity record for you to borrow: no FWD, no claim constructions, no expert declarations, no institution decisions. Any unpatentability position you wanted would have to be built from scratch. You will not need one, because expiration and laches/timeliness do the work.

Pattern signals: none, and that is itself the finding. No repeat petitioner, no serial challenges, no patent-owner PTAB appeal campaign (there is no adverse decision to appeal), and no defensive aggregator (Unified Patents, RPX, et al.) activity — Unified's page for '720-type art references appears in search results only as citation linking to a different, unrelated patent (US 12,089,889), not as a challenge. The patent-owner chain is Vesta Medical, Inc. → Sherwood Services AG (assignment recorded 1999-06-01) → Tyco Healthcare Group AG → Covidien AG (name changes/mergers recorded 2010-09-21), with Covidien AG shown as current assignee and the "Expired - Lifetime" status confirmed. A pharmaceutical/medtech major with a 1990s balloon-ablation portfolio and no IPR record on its own expired patent is a strong signal that assertion of this specific patent is not part of anyone's strategy.

Recommended next steps

1. Lead with expiration, not validity. The authoritative source is the patent's own record: US 5,562,720 on Google Patents shows Anticipated expiration 2013-10-08 and Status: Expired - Lifetime. Confirm independently in USPTO Patent Center (application 08/319,216) and pull the maintenance-fee history — an early lapse under 37 C.F.R. § 1.362 could shorten exposure even further than the 20-year term.
2. Verify the absence of PTAB activity on the record, not just in ODP. Search PTAB E2E (PTACTS) by patent number and by all family members (5,277,201 / 5,443,470 / 5,443,463 / 5,643,304 / 5,713,942), and sweep the federal dockets via CourtListener. Caveat on confidence: I verified the '720 patent itself carefully; my family-wide negative is based on targeted searches, not an exhaustive per-patent PTACTS pull, so treat "no family IPRs" as high-probability rather than certain.
3. No trial milestones to calendar. Because no proceeding was ever instituted, there is no § 316(a)(11) one-year FWD deadline, no institution-decision deadline, and no oral hearing to track. If the ODP ingest is simply stale and a petition surfaces, the milestones to diarize would be: filing date + 6 months (PO preliminary response / institution deadline under § 314(b)), institution + 12 months (statutory FWD deadline), with oral hearing typically ~2-3 months before the FWD.
4. Plainly stated for the record: there are no AIA trial proceedings on US 5,562,720, so there is nothing to settle, nothing to appeal, and no FWD to quote. The absence of PTAB activity here is not the usual "well-asserted patents eventually attract IPRs" anomaly — it is the normal signature of a patent that died of old age in 2013 before the modern IPR era gave anyone a reason to attack it. Treat any current assertion of this patent as a term/standing problem first, and a validity problem never.

I'll research the assignment record for US 5562720. Let me run targeted searches on the assignment chain and the entities involved.

Let me dig into the corporate history and attempt to surface specific reel/frame records.

Let me try to surface the actual reel/frame records and the correspondent of record.

Assignment Record Analysis — US 5,562,720

Critical methodological caveat up front: In this session I was unable to reach the USPTO Assignment Center (assignmentcenter.uspto.gov / assignment.uspto.gov) and therefore could not retrieve the reel/frame numbers, execution dates as recorded, or — most importantly — the correspondent of record for any link in this chain. Those fields are load-bearing for signal #3 (repeat correspondent) and for detecting anonymous-LLC patterns. Everything below is reconstructed from the Google Patents legal-events record supplied as the authoritative text for this patent. I have not invented reel/frame numbers or correspondent names to fill the gap; where a field is unknown I say so. A reel/frame-level verification requires a direct Assignment Center query (and a paid docket/directory cross-check), which was not possible here.

I also flag one contradiction with the taxonomy I was asked to use — see the Verdict.

Inventors

Basis for the employer inference: the application (Ser. No. 08/319,216, filed 1994-10-06) names Vesta Medical, Inc. as original assignee, and the first recorded reassignment (executed 1995-02-10) is an "ASSIGNMENT OF ASSIGNORS INTEREST" in which all six inventors are assignors to Vesta Medical, Inc. That is the standard evidence that all six were Vesta personnel at filing. I could not independently verify individual employment contracts.

Pattern notes:

• No sign of the "all inventors depart within 12 months" fire-sale precursor. The six inventors signed over their rights to their employer (normal employee assignment), and the patent stayed with Vesta Medical for ~4 years after issue before the corporate acquirer stepped in.
• The record spells inventor #5 as "MARION, ROGERT L." in the 1995-02-10 reassignment text — an apparent typo for Robert L. Marion (the inventor of record and the Radaris bibliographic listing both render "Robert L. Marion"). Flagged, not corrected.
• Multi-inventor, single-employer, no inventor-owned or university co-ownership — a clean corporate-owned chain from day one.

Original assignee

Vesta Medical, Inc. — Palo Alto, CA.

• Line of business: an early-1990s medical-device venture developing a radio-frequency endometrial ablation system (the "Vesta system") as an outpatient alternative to hysterectomy. The claimed ablation balloon/bladder and its control circuitry are squarely the company's core product platform, not a side patent.
• Did it ship a product embodying the claims? Yes — the device entered clinical study. Interim Results of the American Vesta Trial of Endometrial Ablation (Corson et al., J. Am. Assoc. Gynecol. Laparosc. 6(1):45–49, 1999; PubMed 9971850) is a multicenter randomized trial of the Vesta system versus resection/rollerball. This is product-in-commerce evidence, not merely a paper patent.
• Current status: acquired / dissolved as an independent entity. Vesta Medical's assets (including this patent family) passed to Sherwood Services AG via the assignment recorded 1999-06-01. Sherwood was part of the Tyco Healthcare group (Tyco Healthcare acquired Sherwood, Davis & Geck in 1998). I found no evidence of a Vesta Medical bankruptcy filing — the transition reads as a trade acquisition, not a Chapter 7/11 fire-sale. (Flagged as unverified for want of a docket search.)
• Post-acquisition product footprint: Sherwood Services AG filed the VESTA word mark (Ser. No. 75643543) on 1999-02-19 for "thermal ablation devices for use in endometrial ablation," which was then abandoned 2000-02-28 for failure to respond. That is consistent with the product line being folded into the acquirer's portfolio and/or wound down quickly. I have no evidence that any current owner still markets a product embodying these claims.

Assignment timeline

Reel/frame, execution date, and correspondent were not retrievable in this session (Assignment Center unreachable). The events below are dated from the Google Patents legal-events record in the authoritative patent text; they should be re-verified against the Assignment Center before relying on them.

1. ~1994 (filing) / 1995-02-10 (recorded) — Reel unknown/unknown

   • Conveyance: Assignment of inventors' interest ("ASSIGNMENT OF ASSIGNORS INTEREST")
   • Assignor: Striegler, Thomas D.; Sullivan, Vincent N.; Roy, Loren L.; Marion, Robert L. (recorded "Rogert L."); Stern, Roger A.; Richman, Roxanne L. (all six)
   • Assignee: Vesta Medical, Inc. (Palo Alto, CA)
   • Correspondent: unknown — not retrieved
   • Context: Initial employee→employer assignment of the CIP application; perfects Vesta's chain of title. (Note the ~9-month gap between the 1994-10-06 filing and the 1995-02-10 execution — routine for a pending application, not a red flag.)

2. ~1998–1999 (executed) / 1999-06-01 (recorded) — Reel unknown/unknown

   • Conveyance: Assignment
   • Assignor: Vesta Medical, Inc.
   • Assignee: Sherwood Services AG (Schaffhausen, Switzerland)
   • Correspondent: unknown — not retrieved
   • Context: Acquisition — Vesta Medical's patent portfolio absorbed into the Tyco Healthcare group via Sherwood Services AG. This is the operating→operating transfer that ends any independent-vester period.

3. 2007–2008 (effective) / 2010-09-21 (recorded) — Reel unknown/unknown

   • Conveyance: Change of Name
   • Assignor: Sherwood Services AG
   • Assignee: Covidien AG
   • Correspondent: unknown — not retrieved
   • Context: Internal reorg / change of name only — Sherwood Services AG was renamed within the Tyco→Covidien corporate reorganisation (Tyco Healthcare spun off as Covidien in June 2007). No change in beneficial ownership.

4. 2007–2008 (effective) / 2010-09-21 (recorded) — Reel unknown/unknown

   • Conveyance: Merger
   • Assignor / Assignee as recorded: "Assigned to TYCO HEALTHCARE GROUP AG — MERGER — Assignors: COVIDIEN AG" and a parallel "ASSIGNED TO COVIDIEN AG — CHANGE OF NAME — Assignors: TYCO HEALTHCARE GROUP AG"
   • Correspondent: unknown — not retrieved
   • Context: Internal reorg only. ⚠️ The Google Patents record is internally scrambled here: a "merger of Covidien AG into Tyco Healthcare Group AG" is backwards relative to the known corporate history (Tyco Healthcare Group AG → Covidien AG). Treat these two 2010-09-21 entries as a single reorganisation recording (name change + intra-group merger) and re-pull the raw reel/frame documents to resolve direction.

Terminal state of record: current assignee Covidien AG (per Google Patents). Legal status "Expired – Lifetime," anticipated expiration 2013-10-08. Not in the assignment record but relevant to who owns it today: Medtronic acquired Covidien in 2015, so the practical current controller of any residual rights is Medtronic — I flag this as an inference, not a recorded assignment, and it was not verifiable here.

Timeline diagram

timeline
    title Ownership of US 5562720
    1992 : Earliest priority from parent case
    1994 : CIP application filed Oct 6
    1995 : Six inventors assign to Vesta Medical
    1996 : Patent issues Oct 8
    1999 : Vesta Medical assigned to Sherwood Services AG
    2007 : Tyco Healthcare spun off as Covidien
    2010 : Name change and merger recorded to Covidien AG
    2013 : Patent expires Oct 8
    2015 : Covidien acquired by Medtronic

NPE / troll-pattern signals

Verdict

Operating-company assertion — (chosen as the closest of the five options, with an explicit caveat). The entire recorded chain is operating medical-device manufacturers (Vesta Medical → Sherwood Services AG → Covidien AG), with zero NPE signals: no shell-entity transfer, no known asserter, no cascading LLC transfers, no privateering, no bankruptcy. Caveat / contradiction to flag: the "is suing actual competitors" prong of this label is not met — the prior Litigation section found no assertion of this patent at all, and it expired 2013-10-08. Strictly speaking the taxonomy has no clean bucket for an "operating-company-owned, never-asserted, expired" patent: "Operating-company assertion" overstates the assertion history, and "Defensive / non-asserting" is also wrong because the chain does not terminate at a defensive aggregator. I selected Operating-company assertion because the dominant, verifiable fact is operating-company ownership with no NPE involvement, but the correct one-line characterisation is operating-company-owned and non-asserted.

Verification links:

• USPTO Assignment Center: https://assignmentcenter.uspto.gov/
• Google Patents (legal events / current assignee): https://patents.google.com/patent/US5562720/en

Outstanding items requiring a live Assignment Center pull (not obtained here): reel/frame for each of the four events above; exact execution vs. recording dates; and the correspondent of record for each filing — the latter being the field most likely to change signal #3 from "unclear" to a definitive call.

I'll research the prior art cited against US 5,562,720. Let me pull the citation records from multiple sources.

I have the front-page citation list. Let me get the complete list (including the continuation page) and details on the key references.

Let me retrieve the complete citation list, including the continuation page and foreign references.

Search confirmation — USPTO record for US 5,562,720

I searched the USPTO/Google Patents record for the exact number 5,562,720 (not similar numbers). The record confirms: US 5,562,720 A, "Bipolar/monopolar endometrial ablation device and method," App. No. 08/319,216, filed Oct. 6, 1994, granted Oct. 8, 1996, Vesta Medical, Inc., 4 claims, 19 drawing sheets, Primary Examiner Lee S. Cohen. This matches the bibliographic section already generated — I won't repeat it here.

The authoritative prior-art record for this patent is the "[56] References Cited" block on the printed face of the patent plus the references discussed in the specification's Background section. Note up front: the front-page list is printed in two columns and continues onto a second page, and I was only able to retrieve the first page (through U.S. 4,773,899) plus the foreign/NPL lines. I could not retrieve the second-page continuation (references issued from roughly 4,77x,xxx onward, likely including 4,979,949 and 5,045,056) from the sources reachable in this session. I flag that gap explicitly rather than guess.

The citation record (verbatim as retrieved)

U.S. Patent Documents (issue dates as printed on the patent face):

Foreign Patent Documents: EP 0115420 (Aug. 1984); EP 0407057 (Jan. 1991); FR 2573301 (Nov. 1984); FR 2679456 (Jan. 1993); DE 8527331.7 (Sep. 1985); DE 3516830 (Nov. 1986); WO 87/01276 (Mar. 1987); WO 90/07303 (Dec. 1990).

Other Publications: Ryan, "Hyperthermia Overview Using Microwave Antennas"; Coughlin, Thermoradiotherapy; Dolan, "Devices: Replacing the Roto-Rooter"; Babcock et al., "Endometrial Ablation," Therapeutic Hysteroscopy: Indications and Techniques, pp. 148–163; Uterine Resectoscopes for Endometrial Ablation and Resection (Karl Storz).

Specification-discussed prior art (Background §): U.S. 4,979,949; U.S. 5,045,056; U.S. 4,662,383; U.S. 4,676,258.

Relevance analysis — which claims could be affected under 35 U.S.C. § 102

Important framing before the reference-by-reference analysis

These are narrow claims. Claims 1–4 (as summarized in the earlier section) are all about one thing: a switching means that can selectively deliver either bipolar or monopolar RF to an electrode array/balloon. Claims 1 and 3 require both modes plus a selector; claims 2 and 4 add selectable pairs.

Because the anti-anticipation rule of § 102 requires a single reference to disclose every element as arranged in the claim (no pick-and-choose across references), my honest bottom line is:

None of the retrieved references is a clean § 102 anticipation of claims 1–4. The references below are strong § 102 art for the individual building blocks (RF balloon electrode, resistive tissue heating, thermistor feedback, expandable member) and strong § 103 art in combination, but the selectable bipolar/monopolar switching feature — the actual point of novelty — does not appear in any single retrieved reference.

Priority-date caveat (pre-AIA § 102(a)/(b)/(e)): US 5,562,720 is a pre-AIA patent (effective filing 1994; 1992 parent priority). If any claim is not supported by the earlier applications, its effective date is Oct. 6, 1994; nearly every front-page reference issued well before Oct. 1993 and is therefore § 102(b) art (printed publication/patent more than one year before filing) regardless.

Tier 1 — Core references (most relevant)

1. U.S. 4,979,949 — the closest single-concept reference (apparatus/method of RF balloon ablation)

• Scope: Thermal ablation of the mucosal lining by resistive heating with an RF balloon electrode, current delivered from an electrode in the balloon via a conductive inflation liquid. Discussed at length in the '720 Background.
• § 102 relevance: Discloses the "electrode means" + "RF power means" + expandable-member inflation of claims 1 and 3. The '720 specification itself distinguishes it: (a) power loss in the conductive fluid and (b) it "cannot be adapted for anything but a single electrode arrangement." That express admission means it cannot anticipate claim 1 (no bipolar/monopolar switching means; no plurality of independently addressable electrodes) or claim 2 (bipolar pairing). It is § 102 art for the generic RF-balloon concept only.

2. U.S. 5,045,056 — heated-fluid balloon for thermal ablation

• Scope: Balloon catheter supplied with heated fluid for thermal ablation of hollow organs (Background §).
• § 102 relevance: Discloses the expandable balloon/conformal-contact element of claims 1 and 3. It uses a thermal fluid, not bipolar/monopolar RF, so it cannot anticipate any of claims 1–4 as a whole; it is § 103 fodder for the balloon element.

3. U.S. 4,662,383 — Sogawa et al., "single electrode enclosed in expanded balloon" (microwave/high-frequency)

• Scope: Application of microwave/high-frequency RF energy to destroy tissue using a single electrode in an expanded balloon (Background §; also on the front-page list).
• § 102 relevance: Singular-electrode — anticipates nothing in claims 1–4 (which require a plurality of electrodes with selectable bipolar/monopolar delivery). Relevant only as the "single-electrode RF balloon" baseline the invention improves on.

4. U.S. 4,676,258 — Inokuchi et al., electrode in expanded balloon

• Scope: Same family of "single electrode in expanded balloon" RF/microwave tissue destruction (Background §; front-page list).
• § 102 relevance: Same as above — baseline art; cannot anticipate claims 1–4. Note this is the reference the patent's own later litigants (Edwards side) cite heavily; but as to '720's own claims it is element-level art only.

5. U.S. 3,924,628 — Droegemueller et al., Dec. 1975 (endometrial ablation probe)

• Scope: Uterine/endometrial ablation instrument (a cryo/thermal intrauterine device).
• § 102 relevance: General endometrial-ablation field art; discloses organ-conforming ablation, not RF bipolar/monopolar switching. Cannot anticipate claims 1–4; supports § 103 field-of-invention arguments.

6. U.S. 4,754,752 — Ginsburg et al., Jul. 1988 (catheter/balloon with RF or laser tip)

• Scope: Catheter balloon device with a heating/ablation element.
• § 102 relevance: Supports the "expandable member carrying an electrode" limitation of claims 1/3; silent on switching modes.

7. U.S. 4,754,757 / 4,758,592 / 4,771,778 — Feucht; Horrobin; Mar

• Scope: These are among the "expandable/electrode-instrument" cluster (Horrobin is a pharmaceutical/ablation preparation; Feucht relates to an instrument with a balloon/electrode). I have not verified the exact subject matter of each of these from the record and will not overstate it. They are § 103 support references, not § 102 anticipations of claims 1–4.

8. WO 90/07303 (Dec. 1990) and EP 0407057 (Jan. 1991) — foreign RF/catheter ablation

• § 102(b) relevance: Printed publications more than one year before the 1994 filing. As above, element-level art (RF tissue ablation / catheter electrode arrays); I did not retrieve the disclosures in enough detail to assert a specific § 102 anticipation, and I state that honestly rather than guess.

Tier 2 — The rest of the face-of-patent list

The remaining ~35 U.S. references (from Chapman 1,827,306 in 1931 through Mar 4,771,778 in 1988) are crowded-field/background art spanning: early electrosurgical and diathermy instruments (Chapman, Armao, Simon, Hassen, Farin, Tischer), microwave/RF hyperthermia applicators (Sterzer 4,311,154, Cain 4,549,533, Turner 4,658,836, Boddie 4,674,481), gynecological/uterine devices (Zoumboulis, Droegemueller, Eden 4,349,033), thermometry/control (Badger 4,638,436), and balloon/catheter drug or fluid delivery. These are cited for completeness of the field; none that I retrieved discloses the claimed selectable bipolar/monopolar switching means, so none anticipates claims 1–4, and their combination against the claim set would be a § 103 question, not § 102.

§ 102 mapping — quick reference

Caveats you should carry forward

1. Data gap (material): I could not retrieve the second page of the "[56] References Cited" list. Any § 102 analysis is therefore incomplete until that page (and the second page of "Other Publications") is obtained directly from the patent PDF at http://patentimages.storage.googleapis.com/42/7e/63/6b94e8b0399b7f/US5562720.pdf.
2. I did not fabricate descriptions. For references whose subject matter I could not verify from the record (e.g., Feucht 4,754,757, Horrobin 4,758,592), I deliberately declined to assert specifics.
3. CIP-parent nuance: US 5,277,201, 5,443,470 and 5,443,463 are listed under "Related U.S. Application Data." Because '720 claims their benefit, they are generally not § 102 prior art against '720 for claims entitled to that priority — unless a given '720 claim is supported only by the Oct. 6, 1994 CIP disclosure, in which case a parent could be § 102(e) art. I flag this as a real but fact-specific risk rather than resolving it.
4. This patent is itself prior art, not a target: as noted in the litigation section, US 5,562,720 ("Stern") is cited as Ex.1033 in PTAB IPR2024-00278 (Patent 11,033,318 B2), where Petitioner used Stern's FIG. 15 switch matrix and bipolar electrode pairs as the "implementation details" for selectable bipolar RF delivery. That confirms the switching feature is the doctrinal heart of '720 — and reinforces that it is the very element absent from the pre-1994 prior art retrieved here.

Bottom line: On the retrieved record, the references cited against 5,562,720 are § 102 art for individual components (RF balloon electrode, expandable conforming member, resistive tissue heating, thermometry) and § 103 art in combination, but no single retrieved reference anticipates any of claims 1–4, because none discloses the claimed selectable bipolar/monopolar switching means. A definitive anticipation analysis requires the missing second-page citations listed on the patent face.

I'll gather the cited prior art from the patent's reference lists before building the § 103 analysis.

Let me pull the specific references cited on the patent and check key secondary references.

Obviousness Analysis — US 5,562,720 under 35 U.S.C. § 103

Note on framing. This is a pre‑AIA patent (effective filing Oct. 6, 1994; priority May 1, 1992), so pre‑AIA §§ 102/103 and pre‑AIA § 102(e) reference dates apply. I build on the previously generated summary and litigation sections; I do not repeat them. Two explicit flags carried forward:

• Contradiction flag (existing): Google Patents lists priority as 1992‑05‑01; Unified Patents lists 1992‑04‑30. Unresolved; both predate all references below, so it does not change this analysis.
• New contradiction flag: the patent’s Discussion of Background cites U.S. Pat. No. 4,979,949 for gallbladder RF‑balloon ablation. The document I retrieved whose disclosure matches that description is headed 4,979,948 (“Method and apparatus for thermally destroying a layer of an organ”), e.g. http://patentimages.storage.googleapis.com/15/57/e7/985577a9653c3f/[US4979948](/patent/US4979948).pdf and https://uspto.report/patent/grant/4,979,948. I use that retrieved text as the substantive reference and do not auto‑correct the ’720 citation.

1. Legal framework and POSITA

Framework. Graham v. John Deere (scope/content; differences; PHOSITA level; secondary considerations), applied through KSR Int’l v. Teleflex (predictable combinations of known elements, “design choice,” and the “improve a similar device in the same way” rationale are sufficient for motivation). All four claims are means‑plus‑function heavy (“electrode means,” “radio frequency power means,” “switching means,” “first/second/third means”), so § 112 ¶ 6 construction governs: the disclosed structures are the balloon surface electrodes (FIGS. 4, 6–9, 19, 36–38), the RF generator/controller of FIG. 5 (156/158), and the switch network of FIG. 15 (switches 232–248), plus equivalents.

POSITA. An electrosurgical device engineer (BS in EE/MechE or equivalent) with ~3–5 years in RF tissue‑ablation catheters/balloons, familiar with: balloon‑conforming organ‑lining ablation, multi‑electrode arrays with thermistor feedback, and the standard monopolar/bipolar modes of commercial electrosurgical generators.

Claim scope (per the earlier summary — paraphrase, not certified verbatim).

• Claim 1: electrode means + RF power means (>250 kHz; uniform 45–90 °C) + switching means with (i) bipolar means, (ii) monopolar means, (iii) selector.
• Claim 2: bipolar between selected ones of a plurality of electrodes.
• Claim 3: method — plurality of electrodes against the organ; RF source; control for bipolar or monopolar.
• Claim 4: bipolar to selective pairs.

Important corollary: the extensive manufacturing disclosure (dip‑molding, emulsion‑on‑base, adhesive‑island transfer, jigs — FIGS. 20–33) is unclaimed in the issued 4‑claim set, so it is not part of § 103 analysis except as specification support.

2. The prior–art record actually available

§102 qualification: ’948, ’056, ’383, ’258 are pre‑1992 § 102(b) art. Protell/Moore are § 102(b) printed publications. ’591 is § 102(e) art through its 1988/1990 chain and a different inventive entity (Lennox et al.), so § 103(c) common‑ownership does not shelter it.

3. Grounds of rejection

Ground A — ’948 (’949) in view of the admitted bipolar/monopolar knowledge of electrosurgery (Protell/Moore), optionally with ’056

• (a) electrode means against organ tissue: met — ’948’s capacitive balloon electrode contacts the mucosa; ’056/’383/’258 teach the same in a conforming balloon.
• (b) RF power means >250 kHz, 45–90 °C: met — ’948 runs ~2 MHz, its control circuit regulates current to hold the lining at a preset ~50 °C, and the whole point of the design is selective heating of the lining with the deeper layer <42 °C. A claimed range (45–90 °C) reads on a disclosed species (50 °C) with a result‑effective variable; under KSR, arriving at the range edges by routine optimization is obvious absent unexpected results. “Uniform temperature” is a functional result the ’948 thermistor/feedback loop already exists to produce.
• (c)(ii) monopolar means: met — ’948’s dispersive electrode 120 on the skin is the classic monopolar return.
• (c)(i) bipolar means + (c)(iii) selector: supplied by the general knowledge of RF electrosurgery, evidenced by the Protell and Moore 1978 studies expressly comparing bipolar vs. monopolar in gastric applications, and by Lennox ’591’s in‑balloon two‑contact arrangement, which shows bipolar current flow between electrodes sharing one chamber. That a generator front‑end can be switched between the two modes is exactly the kind of “known design choice” KSR permits to be resolved against patentability; the ’720 itself treats it as a mode selection made by the operator by closing/opening switches, not a new energy modality.

Why combine. ’948 already teaches the unwanted consequence of monopolar return‑path unpredictability — the return path depends on pad placement and patient anatomy. The artisan seeking to (i) localize heating to the endometrium, (ii) keep the myometrium ≤42 °C, and (iii) accommodate asymmetric uterine cavities would readily add the long‑known bipolar option alongside the disclosed monopolar pad, because bipolar inherently concentrates current between closely spaced electrodes and monopolar inherently gives broader/deeper coverage. Same field, same problem, same energy, predictable result — the KSR “improve a similar device in the same way” rationale.

Ground B — ’383/’258 + ’056 + ’948 + bipolar/monopolar knowledge

Cumulative to Ground A and useful if the examiner treats ’948 as limited to the gallbladder/electrolyte coupling: ’383/’258 supply the electrode‑in‑expanded‑balloon architecture and RF/microwave delivery; ’056 supplies the conforming‑balloon lumen technology and the motive to conform an expandable member to the organ lining; ’948 supplies the temperature‑feedback regulation; the Protell/Moore art supplies bipolar/monopolar selectivity. The ’720’s background section effectively concedes that these teachings, taken together, describe the whole device minus the dual‑mode selector — a textbook “the only difference is a known operating mode” case.

Ground C — US 5,368,591 (Lennox) + ’948 + ’056

’591 is the most structurally on‑point teaching of an RF ablation balloon with multiple electrodes and current flowing between them under thermistor control (bipolar‑between‑electrodes; the difference is merely that ’591 heats the fluid and transfers heat through the wall rather than passing current through tissue, whereas ’948 passes current through tissue). ’948 alone discloses tissue‑current heating with a monopolar return. Combining them (both catheters, both balloons, both RF, both thermistor‑regulated) to obtain a device that can run tissue‑current ablation in either mode is a combination of references addressing the same problem with no change in principle of operation — a strong § 103 case. Motivation: bipolar mode limits depth/return unpredictability and spares adjacent bowel/bladder; monopolar mode promotes uniform large‑area lining coverage; the physician picks per patient, exactly as the ’720 describes.

Ground D — the CIP parents (US 5,277,201 / 5,443,470 / 5,443,463) + the admitted bipolar/monopolar knowledge

Because ’720 is a CIP, subject matter present in the parents is entitled to the 1992 priority date, but any new matter (the bipolar/monopolar switch matrix and selector) is entitled only to the Oct. 6, 1994 filing date. The parents already disclose the balloon electrode array, thermistor feedback, 45–90 °C endometrial heating, and the return‑electrode pad. The sole new contribution is the selector. Under KSR, adding a known mode‑select capability to an otherwise entirely disclosed ablation apparatus — where the specification admits “improved control can be achieved in many cases if a bipolar operation is utilized” but “in some instances the precise control is either not necessary or treatment can best be performed in a monopolar arrangement” — is the paradigm of an obvious, predictable improvement. Caution: whether the parents are technically § 102(e) “by another” turns on inventive‑entity identity (parents list Stern/Sullivan/Marion; ’720 lists six inventors), so they are best used as background/admission evidence rather than as the primary anticipation reference.

Claims 3–4 (method)

Claims 3–4 are the process counterpart and stand or fall with the same art. Every recited step — placing a plurality of electrodes against the organ, connecting an RF source, and controlling the RF to provide bipolar or monopolar application — is disclosed or suggested by ’948 (monopolar control to a setpoint) in view of the Protell/Moore bipolar‑vs‑monopolar art and ’591 (multiple electrodes inside one balloon energized to produce current between them). Claim 4’s “selected pairs” is the routine, disclosed operation of a multi‑electrode switch matrix; the ’720 specification’s FIG. 15 discussion shows that choosing pairs (220–224, 222–226, 220–222) is simple switching, not an inventive step.

4. Secondary considerations / rebuttal

• No nexus evidence available. The patent expired 2013‑10‑08, and (per the earlier litigation section) no district‑court, ITC, PTAB, or Federal Circuit proceeding naming 5,562,720 as an asserted patent was found. The only appearances of this number are as a cited prior‑art reference in unrelated challenges (e.g., PTAB papers in the Edwards‑’535 family, Ex.1033‑Stern). A dormant, 30‑year‑old asserted‑never patent supplies no objective indicia (commercial success, licensing, copying, long‑felt need) that could rebut the prima facie case.
• Predictability. Both modes use the same generator, same electrodes, same frequency band; the difference is which electrodes form the return. Results are predictable.
• Possible counter‑argument. A patent owner could argue that no single reference discloses a selector that toggles between modes within one ablation cycle, and that the “uniform 45–90 °C” language imports a control algorithm. Both arguments are weakened by the ’720’s own specification admissions and by ’948’s setpoint‑regulated thermistor loop.

5. Bottom line

Confidence and limits. High confidence in the architecture of these grounds and in the ’948, ’056, ’383/’258, and ’591 disclosures I retrieved. Lower confidence in the verbatim claim language — as the earlier section noted, the issued claim columns could not be independently re‑retrieved, so the element mapping above rests on the patent’s Summary‑of‑Invention text, which conventionally tracks the claims. Two identifier discrepancies are flagged rather than corrected: (i) the ’720 cites 4,979,949 while the matching disclosure belongs to 4,979,948; and (ii) the priority‑date discrepancy (1992‑05‑01 vs. 1992‑04‑30). A definitive opinion would require the certified claim text from the USPTO PatentCenter image file wrapper and a docket‑grade search for any unexpired continuation claims.