idea-018 · feasibility deck
Every slide states a condition that would have to be true, then reports where it stands using the candidate file's own claim and its own confidence tag. A deck never upgrades a tag, invents a number, or recommends anything, and there is no ask slide.
The chair: engineering. The people who have to build it, test it, manufacture it, and produce the evidence a reviewer will ask for.
How to read this: every slide is a condition, not a conclusion. A bracketed claim reference points into knowledge-base/candidates/idea-018.md — the number is the claim's position in its ## Claims list and the tag is copied from it, never adjusted here. A no-claim marker means nothing in the file speaks to the condition at all. See docs/deck-spec.md.
Would have to be true: The build would have to deliver four things at once: a coil that puts a pulsed electromagnetic field across a long-bone fracture gap; a profile thin enough to be worn under ordinary clothing; a battery that sustains the prescribed field-on hours per day for the length of the course; and an onboard log that records actual field-on minutes against the prescribed schedule, tamper-evidently, and exports a report a prescriber and a DMEPOS supplier can file.
Where it stands: The device category is defined in verified regulatory text — a prescription device providing stimulation through electrical, magnetic or ultrasonic fields, used externally to promote osteogenesis, including "as a treatment for established nonunions or failed fusions" [claim 2: verified] — and the candidate's intended use sits inside that language. The quantities are all blank: no claim in the file carries a waveform specification, a field strength, a coil thickness, a prescribed hours-per-day, a course length, or a battery target. Those blanks are left visible rather than filled, because nothing in the file speaks to any of them [no claim]. The one quantified constraint that does exist is regulatory: (b)(2) requires non-clinical testing verifying that intended design outputs are delivered to the patient, thermal safety and reliability, signal characteristics within safe physiologic limits, and device reliability consistent with expected use-life [claim 3: verified].
What would settle it: The labeling of a legally marketed incumbent device — Orthofix Physio-Stim or Zimmer Biomet OrthoPak — which states prescribed daily hours and course length; retrievable from FDA's PMA labeling or the manufacturer's IFU by a human, since this repo has no PMA or labeling connector. Then an internal requirements document derived from it.
If it's false: A device with no numeric output specification cannot be tested against (b)(2) at all — the special control is written as verification that design outputs are delivered, which presupposes a specified output. Slide 5's bench programme has no acceptance criteria until this slide is filled in.
Would have to be true: A pulsed electromagnetic field delivered externally would have to raise the union rate in established long-bone nonunion — bone that has already stopped healing for three or more months — by a margin large enough for a prescriber to choose it over revision fixation, at the field magnitude a wearable coil can actually put across the gap.
Where it stands: The file records this as a named hole, not as support: the published evidence base for PEMF specifically in established nonunion was not retrieved in either direction [claim 25: unconfirmed] — though the verifier's sweep shows the field is not empty (80 matches, including a 2024 systematic review update), with none read or appraised, so none of it carries a tag. The proposition itself was not a claim until this deck appended it [claim 40: unverified]. The only trial evidence verified in the file cuts the other way and must not be buried: the TRUST trial — 501 patients, 43 North American academic trauma centres, sham-controlled — concluded that postoperative LIPUS after tibial fracture fixation "does not accelerate radiographic healing and fails to improve functional recovery" [claim 24: verified]. The file is explicit about its scope: a different modality (ultrasound, not PEMF) in a different indication (fresh operatively managed fractures, the indication this candidate gives up), so it is not evidence about this device — but it is the best-known trial in the adjacent space and it is negative. That the device class has been marketed for decades is a plausibility signal only [claim 5: verified], [claim 19: unconfirmed].
What would settle it: A literature-detail sweep over the leads already in claim 25's verifier note — PMID 39387850 (PEMF systematic review update, 2024), 42270187, 41244766, 42305571 — appraised specifically for established nonunion versus fresh fracture, with effect sizes and control arms extracted. Free, a few hours, and it is the cheapest unclosed item on this deck.
If it's false: Factor 6 (Mechanism and clinical risk) does not stay at its drafted 2/5, it falls — and (b)(1)'s clinical data requirement becomes unmeetable, because there is no route to a 510(k) whose clinical data show the device does not work. The narrowing would then have bought a cheap pathway to an indication the evidence does not support.
Would have to be true: The 510(k) would have to be built against an available predicate, and the submission would have to carry every special control at 21 CFR 890.5870(b) — including clinical data, not bench data alone.
Where it stands: The special controls were read in full and are verified: (b)(1) clinical data demonstrating the device performs as intended, with imaging data demonstrating fusion at the treatment site; (b)(2) non-clinical performance testing (design outputs, thermal safety, signal within safe physiologic limits, use-life reliability); (b)(3) biocompatibility of patient-contacting components; (b)(4) electrical safety and EMC; (b)(5) software verification, validation and hazard analysis; (b)(6) labeling comprehension testing showing a patient can correctly use the device from the IFU alone; (b)(7) labeling with warnings on compromised skin, skin sensitivities and implanted medical devices, plus a summary of supporting clinical data [claim 3: verified]. Two consequences the file flags: this is not a bench-only submission, and (b)(1)'s imaging requirement is written in fusion terms that a nonunion indication will have to address. The predicate is the harder problem: no 510(k) has ever been cleared under LOF or LPQ — an empty openFDA query across the whole record, cross-checked by device name — so four months after the route opened there is nothing cleared under 890.5870 to be substantially equivalent to, and whether a pre-reclassification PMA device can serve is unresolved [claim 20: verified]. This deck states that availability as its own proposition [claim 38: unverified]. The route exists at all only because of the reclassification [claim 1: verified], [claim 5: verified], [claim 6: verified], and staying inside the regulation's indication language is the Generator's inference, not an FDA statement [claim 7: unconfirmed].
What would settle it: An FDA pre-submission asking both questions in one meeting: predicate availability for a pre-reclassification PMA device, and what clinical data set and imaging endpoint satisfy (b)(1) for a nonunion rather than a fusion indication. The file already names a pre-submission as the check for claim 7; this is the same meeting. Re-running clearances --product-code LOF --since 2026-05-18 periodically costs nothing and would catch the first predicate the moment it appears.
If it's false: Without a predicate the submission is a 510(k) with nothing to compare to, which in practice means De Novo — a different evidence burden and a different calendar. Factor 1 (Regulatory, drafted at 3/5 with this exact discount stated) and Factor 7 (capital intensity and time-to-revenue, held at 3/5 for the same reason) both fall, and the candidate's whole premise — that the narrowing bought a cheap pathway — goes with them.
Would have to be true: The coil would have to be thin and flexible enough to disappear under clothing and still put the incumbent devices' field magnitude across a fracture gap that may sit several centimetres deep in a femur or tibia, without exceeding the thermal limits or the safe physiologic signal limits the special controls require — and without a battery that defeats the low profile.
Where it stands: This is the engineering trade the whole differentiation rests on and the file says nothing about it; this deck put it on record [claim 39: unverified]. The constraints it must satisfy are verified [claim 3: verified], and they are exactly where a thinner, closer-to-skin coil gets harder: thermal safety, signal characteristics within safe physiologic limits, and reliability over the expected use-life. The assumption that the form factor pays off in adherence sits on the desirability deck [claim 29: unconfirmed], so the trade is being made against an unmeasured benefit.
What would settle it: Field mapping on a limb phantom with the coil at realistic standoff across body habitus and placement error, measured against the incumbent device's labeled output (Slide 1's retrieval), plus a thermal soak at the prescribed daily duty cycle. A bench programme, weeks not months, and it needs no animal or human subject.
If it's false: If the low-profile coil cannot reach the field magnitude, the candidate has two choices and both are bad: raise the profile, losing the differentiator that Slide 2 of the desirability deck rests on, or keep the profile and change the output, which invalidates any substantial-equivalence argument built on the incumbent's performance and lands back on Slide 3's predicate problem.
Would have to be true: Before any patient is enrolled, a bench rig would have to show measured field output at the target depth meeting the specification, thermal performance within limits across the full daily duty cycle, use-life reliability over the full course length, biocompatibility of every skin-contacting component in a garment worn for months, EMC, and software V&V and hazard analysis for the logging function — and the tamper-evidence of the log would have to survive a deliberate attempt to defeat it.
Where it stands: Six of those seven items are not aspirations but the verified text of the special controls at (b)(2)-(b)(5) [claim 3: verified]. The seventh — that the log resists tampering well enough for a payer or supplier to rely on it — is nowhere in the file as an engineering requirement; what the file has is the commercial assumption that anyone values such a log [claim 30: unconfirmed]. Note what this slide does not require: the device is externally worn and non-invasive [claim 2: verified], so the gating evidence is bench plus clinical data, not an animal study — and no agent in this repo greenlights an animal study in any case.
What would settle it: A written bench protocol mapped line-by-line to (b)(2)-(b)(5), drafted against the retrieved incumbent labeling, plus a red-team attempt on the log (remove the coil, run it on a table, spoof the clock) with the results in the hazard analysis. Stage 7's minimum-viable-bench-evidence list is this slide expanded.
If it's false: Any single failed bench item stops the 510(k) before it is filed, and a failed tamper-evidence test specifically removes the only feature that distinguishes this from a commodity stimulator — it would make Slide 5 of the viability deck (what stops a fast-follower) unanswerable.
Would have to be true: The garment-plus-electronics assembly would have to be manufacturable at a unit cost below what Medicare pays for the device; it would have to survive months of daily wear, skin contact and whatever cleaning a patient actually does to a garment; and a patient at home would have to be able to use it correctly from the instructions for use alone, with no clinician present.
Where it stands: The last of those three is not a nice-to-have but a verified special control: (b)(6) requires labeling comprehension testing demonstrating the patient can correctly use the device based solely on reading the instructions for use, and (b)(7) requires warnings against use on compromised skin or with known skin sensitivities and for patients with implanted medical devices [claim 3: verified] — which is a pointed constraint for a coil integrated into a worn garment. The intended use is prescription home use by adults, so that environment is the design environment. Unit cost against the allowance was not on record and is now [claim 41: unverified]; the allowance it would have to beat is itself an unsourced guess [claim 16: unconfirmed]. Manufacture, supply chain and shelf life are not addressed by any claim in the file [no claim].
What would settle it: A formative human-factors study against a draft IFU, well before the summative comprehension test; a costed bill of materials for the coil, garment and logging electronics at realistic volume, set against the DMEPOS fee schedule PUF for E0747; and a wear and laundering durability protocol.
If it's false: If comprehension testing fails, the home-use indication fails with it and the device needs clinician-applied use — which changes the payment setting and undoes the DMEPOS model the entire viability deck is built on. If unit cost exceeds the allowance, the product is unsellable at the only price the largest payer pays.
Would have to be true: The waveform, the coil geometry, the garment integration, and the tamper-evident adherence-logging and compliance-reporting function would all have to be practicable without a licence from Orthofix, Zimmer Biomet, Bioventus or Enovis — and where they are not, the workaround would have to be a design choice rather than a compromise of the two differentiators.
Where it stands: Unexamined in both directions, and the file says so plainly: no patent search of any kind was performed — not for the waveform or coil geometry, not for the garment-integrated form factor, not for the adherence-logging function — and no patent number or family is named [claim 26: unconfirmed]. The narrower question of what the four named firms hold is equally open; the belief that 1970s-80s foundational PEMF art would be long expired is an inference about a class of patents, not a finding about any patent, and it says nothing about the two modern differentiators where live art is most likely [claim 27: unconfirmed]. Whether protection could be obtained on those differentiators is the viability deck's assumption [claim 36: unverified]. Unexamined is not clear, and the Stage 5 "FTO blocked" kill cannot fire on this line — nor may it be read the other way.
What would settle it: A PatentsView or EPO OPS assignee search against the four firms plus a CPC search on treatment-compliance monitoring — a few hours of analyst time. This repo's patent connector needs a patent identifier (credentials are present; the identifier is not), and it returns filing and grant dates with a naive-expiration caveat, never an FTO conclusion. A real clearance opinion is paid counsel.
If it's false: A live claim over the adherence-logging function would remove the differentiator rather than the device; a live claim over coil geometry would force Slide 4's trade in the wrong direction. Factor 4 (FTO/IP) is a hard-gate factor under the rubric, so this is the one slide on this deck whose answer can end the candidate outright.
Every condition above with nothing verified behind it — the [no claim] markers, plus the unverified claims this deck itself put on record. Read this slide first.
literature-detail sweep over claim 25's leads, appraised.
The unusual part of this deck is how much is verified: claim 3 gives the build spec in FDA's own words, and claim 20 says the route has no predicate in it yet. The engineering unknowns are real, but the two hardest lines here are regulatory judgement and clinical evidence, not hardware.
If only one thing from this chair could be checked: Whether a device legally marketed under a PMA before 2026-05-18 is available to a new entrant as a predicate for a 510(k) under 21 CFR 890.5870 [claim 38: unverified], [claim 20: verified].
This one rather than the others because it decides which build this is. With a usable predicate, the programme is the special-controls list at claim 3 — bench testing, biocompatibility, EMC, software V&V, comprehension testing, and a clinical data set against an existing comparator. Without one, it is a no-predicate submission on a four-month-old regulation, which is a De Novo-scale evidence programme and a different company. Every other condition on this deck — the coil trade, the bench protocol, the manufacturing cost — is scoped by the answer, and the answer costs one pre-submission meeting. The file's own verified finding points at it: zero clearances have ever issued under LOF or LPQ, and that is an empty query, not a query not run.
Naming it is not a recommendation, a gate, or a kill.