HIFU Patient Selection & Contraindications

A refusal is a sale you keep

Nobody sells a machine by describing the clients you should turn away. Your quotation lists handles, cartridges, shot counts, a training call. It won't name the share of walk-ins a competent room declines, and that share is what your results wall becomes.

Price a bad candidate honestly. An hour of room time, a cartridge you can't un-fire, a refund, then a review that outlives the warranty.

Screening is cheap. Refunds aren't.

Grade the laxity out loud, before you quote

Focused ultrasound tightens tissue that still has spring in it. It removes nothing. A 2025 global expert consensus on body treatment names the ideal candidate without hedging: mild to moderate laxity, with enough target tissue at depths the cartridge can reach. The 2023 systematic review of facial tightening arrives from the other side, listing excessive skin laxity as an explicit exclusion criterion, with three pooled studies finding improvement fell as baseline laxity rose.

So grade it in front of the client, out loud, and write it in the file.

Laxity grade	What you see at the consultation	The call
Mild	Fine crepe, jawline still readable, tissue that springs back briskly when lifted	Treat. One full session, review booked at three months.
Moderate	Softening jaw contour, early shadow under the chin, laxity but no surplus skin	Treat, once the expectation conversation is done. The gain is real and often quiet.
Severe	Hanging skin, established jowls, tissue that stays tented after a pinch	Refuse and refer. A surgical problem wearing a non-surgical enquiry.

Age tells you less than the sales script suggests. A forty-year-old with thin, sun-hardened skin can respond worse than a sixty-year-old who stayed covered and kept her weight steady. Grade the tissue, not the birthday.

The bottom row is where money gets lost. Severe-laxity clients arrive wanting a yes, and plenty will pay in full to hear one. Say no anyway. The consensus is blunt that improvements can be subtle and may appear gradually, nowhere near what real facial descent needs.

BMI and volume set a ceiling no setting can raise

Body weight cuts both ways here.

Heavy first. That 2023 review records excessive subcutaneous fat or a BMI above 30 as a frequent exclusion criterion in the trials it pooled, and two studies tied lower BMI to better results: significantly higher subject-rated improvement at a BMI of 25 or under, less improvement above 30. The mechanism isn't mysterious. More volume means more load on the skin envelope, so identical coagulation points buy less visible lift.

Thin clients carry the opposite risk, the one people forget. The 2025 body consensus asks for care with low BMI or substantial weight loss, since less adipose tissue and stretched anatomy bring neurovascular structures closer to the focal point. Recent or past surgery in the field counts too: abdominal hernia, liposuction, abdominoplasty, a caesarean, and abdominal piercings all earn a slower approach than your standard map.

Two habits follow at the desk. Quote a range, never a promise. Tell the client whose weight is the actual problem that her scale will move the result more than your machine will, then be willing to lose the booking.

Hard stops, and the honest blanks

The reference device in this category publishes its instructions for use. Read that document once and you have the spine of your own screening form.

Tier	What sits in it	What you do
Contraindicated outright	Open wounds or lesions in the treatment area; severe or cystic acne there; active implants such as pacemakers or defibrillators; metallic implants in the field	No treatment. Not a lower setting, not a smaller map.
Not evaluated, so treat it as no	Pregnancy and breastfeeding; children; anticoagulant treatment plans; haemorrhagic disorder or hemostatic dysfunction; active systemic or local skin disease that may alter wound healing; herpes simplex; autoimmune disease; diabetes; epilepsy; Bell's palsy	Defer. Where diagnosis is involved, that call belongs to the treating clinician, not your reception desk.
Avoid anatomically	Thyroid gland, thyroid cartilage and trachea; major vessels and nerves; breast tissue and implants; eyes, eyelids and inside the orbital rim	Map around them. Print the list and tape it inside the cartridge drawer.

People misread that middle tier. Not evaluated isn't contraindicated, agreed. You're still not the party who runs the missing study on a paying client, and "the label never actually said no" reads terribly in a complaint file.

Active infection or inflammation in the treatment field is its own defer. Our skin disease atlas lists obvious skin infection and a history of herpes simplex among contraindications for energy work, so a flare postpones the appointment.

Fillers, implants and keloid history

Most genuine refusals live here, where clients are least reliable as narrators.

The same instructions for use state that treatment is not recommended directly over mechanical implants, dermal fillers or breast implants, and that treatment energy is not recommended directly on an existing keloid. Read "directly over" properly. That's a mapping question, not a yes-or-no question. Filler in the nasolabial folds doesn't rule out a submental and jawline map, as long as you know where the product sits.

Which is why you never ask whether she's had filler. Ask where, when, which product, which clinic. People forget, soften the truth, or never knew what was injected into them. Draw it on a face diagram, date it, have her sign it.

Sequencing handles the rest. The aftercare rules in our skin-science training manual, written for energy-based sessions generally, bar dermal fillers and other injectables for two weeks after treatment. Focused heat first, injectables later, never both in one appointment.

Keloid history deserves a real conversation, not a tick box. Our skin disease atlas describes keloids as red to purple nodules appearing weeks or years after an injury, spreading past the original wound margin, with no tendency to resolve on their own, reported incidence of 4.5% to 16% and higher rates among people of African and Hispanic descent. Set that beside what this machine does deliberately. Our light and tissue interaction lecture notes that collagen contracts to roughly a third of its length around 60 to 65 degrees Celsius with tissue integrity intact, while coagulation and necrosis follow above 75 degrees Celsius given enough time. Focused ultrasound aims at that second zone on purpose. In a client whose healing already overshoots, no knob on the console turns that variable down.

Phototype doesn't gate this one. Pigment still does.

Light devices choose their target by absorption. Anderson and Parrish set the principle out in Science in 1983, and every laser in your room still obeys it: a brief enough pulse at a well-absorbed wavelength damages the chromophore and spares its neighbours. For most skin work that chromophore is melanin, which is why darker skin changes your fluence, and why our note on reading Fitzpatrick skin types before you treat exists.

Sound doesn't behave that way. It converges on a geometric focus and heats whatever sits there, so melanin above that focus isn't part of the transaction. The manufacturer's label reflects it, giving the intended population as adult patients of all races and ethnicities, regardless of gender or Fitzpatrick skin type. A 2025 narrative review credits the strong safety record in types III to VI to energy bypassing the melanin-rich epidermis.

Lower risk. Not no risk.

That review also reports two cases of post-inflammatory hyperpigmentation among 49 Chinese patients, both on the forehead, both with the deeper 4.5mm transducer, both resolved within nine months, with none after the operator moved to the shallower 3.0mm cartridge there. Heat landing in the dermis can wake pigment wherever pigment is inclined to wake. Our skin-science training deck grades facial pigmentation P0 to P3, and those definitions are what a screening form needs: P1 skin doesn't readily hold pigment after inflammation or trauma, P3 skin does and clears it slowly. Record that grade beside the Fitzpatrick type. The same manual keeps direct and indirect heat off a treated area for three days, so no sauna and no facial steaming, with extra care for anyone prone to pigmenting.

Want the physics under that? Our technology notes compare how each modality carries energy into skin.

What the file has to hold

Screening you didn't write down didn't happen. That's the whole standard, and it decides whether one bad outcome is survivable.

A signed contraindication checklist from your machine's own manual, not a competitor's website
The laxity grade, plus consultation photographs shot from the same spot under the same light
A dated, signed filler and implant map of the face, naming product and clinic where she knows them
Fitzpatrick type and a separate pigmentation grade, refreshed each visit, not copied forward
Cartridge depths per area, lines delivered, energy level, batch and remaining shot count
Operator name and training date against every session
What the client was told to expect, in writing, including the words subtle and gradual
The three-month review, booked on the day, not vaguely offered
A refusal log with reasons, the best evidence a serious room can produce

Two things to demand before you sign. Ask for the contraindication and precaution pages of the operating manual, in English, as a document, at quotation stage. Then ask which depths the machine genuinely delivers, because a screening protocol means little if you can't name the layer you're treating. Our HF-01 4D HIFU platform ships two handles and seven selectable focus depths from 1.5mm to 16mm, which is why its screening form records a depth and not just a yes.

A supplier who can't hand over that written list has already told you something about what you're buying.

Evidence and further reading

Educational material for equipment buyers and operators. It is not medical advice, an operating protocol or a promise of clinical outcome.

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HIFU Patient Selection: Who to Treat and Who to Refuse