Micro-Focused Ultrasound (MFU) technology is primarily used for skin tightening and lifting treatments. However, there is currently a wide range of MFU devices on the market, with significant differences in transducer modes and parameters. The lack of unified standards in operation has led to frequent adverse events such as localized swelling. To standardize the application of MFU technology, the Anti-Aging Branch of the Chinese Association of Plastic and Aesthetic Surgery has organized and formulated the “Expert Consensus on the Application of Micro-Focused Ultrasound in Facial and Neck Anti-Aging Aesthetics,” which was officially released in 2025. This consensus comprehensively standardizes the application of MFU technology, indications, contraindications, complications, precautions, and peri-treatment management.
1. Mechanism of Action of Micro-Focused Ultrasound Technology
Micro-focused ultrasound delivers acoustic energy to specific areas in the dermis and subcutaneous tissues (such as the dermal layer and the superficial musculoaponeurotic system, or SMAS), forming ultrasound micro-focus points. Through intense vibration of plasmids and positive-negative pressure variations, it produces cavitation and thermal effects. These effects trigger several biological responses, including:
- Enhanced tissue activity under non-thermal effects.
- Enhanced tissue activity under thermal effects without tissue denaturation.
- Thermal denaturation of tissues, leading to coagulation.
- Thermal dissolution effects.
- Cavitation effects.
- Other effects, such as promoting transdermal drug delivery and accelerating the metabolism and absorption of exogenous filler materials.
In the target area, the temperature of the micro-focus point rises to a specific threshold, causing localized thermal coagulation and cavitation in the subcutaneous tissue. This localized micro-injury triggers immediate tissue contraction effects and activates collagen regeneration and tissue repair mechanisms, promoting long-term lifting and tightening of lax skin.
2. Characteristics and Classification of MFU Technology and Transducers
2.1 Characteristics of MFU Technology:
- Frequency range: 4–10 MHz
- Focal depth: 1.5–4.5 mm
- Thermal coagulation point size: diameter less than 1 mm
- Treatment modes: linear, planar, and layered
2.2 Classification of Micro-Focused Ultrasound Transducers:
2.2.1 Classification of Treatment Heads:
Linear Focus Mode (Normal Mode):
- Phase control of single-row or multi-row piezoelectric elements (PZT).
- Energy is focused into a high-density, linear thermal coagulation band (width 1–2 mm).
- The linear thermal coagulation band enables precise tissue remodeling.
Planar Focus Mode (Ultraboost or dot Mode):
- Annular array or two-dimensional phase modulation.
- Energy diffuses into an elliptical focal zone with a diameter of 5–8 mm (thermal diffusion depth 0.5–2 mm).
- Provides uniform heating of the dermis or superficial fat layer.
2.2.1 Classification of Treatment Heads:
2D HIFU, 4D HIFU and 7D HIFU are dot shotting in one line or multiple lines.
MPT (Micro Pulsed Technology Ultrasound) is an upgraded version of the Ultraformer UF3 device with a new design and advanced energy delivery. It provides denser, faster, and more stable ultrasound energy that penetrates deeply into the SMAS layer, resulting in shorter treatment times and longer-lasting effects.
Three energy release modes:
- DOT (Conventional): Delivers energy in precise dots, similar to UF3.
- LINEAR (MP Mode): Releases energy in a dense, stable linear pattern for better coverage.
- CIRCULAR MOTION: Combines dot and linear modes in a circular pattern to nourish the skin surface and enhance radiance.
3. Three Facial Aging Signs and Their Characteristics
Mainly manifested in volume loss, changes in the epidermis, decreased elasticity, increased skin laxity, and tissue displacement.
4 Microfocused Ultrasound Therapy Indications and Contraindications
4.1 Indications:
Facial and neck skin, as well as facial contours, require firming and improvement.
Wrinkle removal and lifting for facial and neck skin with appropriate tissue volume and elasticity, addressing signs of aging, wrinkles, and mild to moderate skin laxity.
4.2 Absolute Contraindications:
① Patients with active herpes simplex virus infection in the treatment area;
② Patients with severely sensitive facial skin;
③ Patients with active-phase dermatological conditions exhibiting Koebner phenomenon;
④ Patients with unhealed wounds in the treatment area or systemic diseases or local infectious skin conditions that may affect healing;
⑤ Pregnant or breastfeeding women;
⑥ Patients with mental illnesses or those with unrealistic expectations of treatment outcomes;
⑦ Patients with severe systemic diseases;
⑧ Other contraindications determined by the physician.
4.3 Relative Contraindications:
① Local areas with metallic implants in the treatment area;
② Local areas with severe or cystic acne;
③ Patients with significant obesity, significant weight fluctuations, or a BMI over 30 kg/m² with treatment needs;
④ Patients with severely sagging facial skin and excessive facial wrinkles or folds;
⑤ Patients with excessive photoaging;
⑥ Patients with severe elastic tissue degeneration or facial paralysis;
⑦ Patients with keloids or a predisposition to keloid formation;
⑧ Patients continuously using systemic corticosteroids or receiving immunosuppressive therapy;
⑨ Patients who have taken psychiatric medications, warfarin, or heparin within the past two weeks;
⑩ Patients with pacemakers or implanted defibrillators should proceed with caution.
5 Pre-Treatment Assessment and Preparation
5.1 Pre-Treatment Assessment:
The primary evaluation includes assessing the facial and neck contours, the volume and morphology of the subcutaneous tissues, the degree of skin laxity and sagging, the extent and cause of any localized depressions (whether due to absolute volume loss, tissue sagging, or ligamentous pulling, etc.), and the presence of dental implants, metal fixation devices in the bone, or deep-seated foreign bodies (including injected materials), etc.
5.2 Pre-Treatment Preparation:
1. Sign the Informed Consent Form
2. Clean and Cleanse the Face
3. Take Photographs
- Frontal view
- Left and right 45° oblique views
- 90° lateral view
4. Prepare Supplies
- Skin cleansing and disinfection products
- Marking pens, rulers, adhesive agents, etc.
5. Use Acrylic Board to Adjust the Equipment
6. Mark and Draw Lines on Localized Areas of the Face
6.1 Marking the Treatment Area
Marking the Treatment Areas
1. Neck and Periorbital Area
- From the mandibular angle, draw a line 1.5 cm below the mandibular margin (as the inner ring of treatment)
- The outer ring is defined by the treatment area’s safety margin (approximately 2.5 cm)
- Mark the inner ring (small area) and outer ring (large area) with appropriate treatment boundaries
2. Facial Area
- Mark a line 1.5 cm around the oral commissure and in front of the tragus
- Nasal base to subnasale region line
- From the oral commissure, extend 1.5 cm to the ear lobe line
- Lines for the lower jaw margin
- Safety area margin, marked 2.5 cm outside the treatment area
3. Submental Area
- Draw a line from below the chin, extending 1.5 cm below the mandibular margin
- From the submental area to the midpoint of the mandible, mark the submental line
- From the thyroid cartilage up to the lower edge of the chin, mark a submental line
- Treatment area defined as the area between the first and second lines
4. Neck Area
- Mark the second line below the lower edge of the chin
- Inner border: the anterior border of the sternocleidomastoid muscle
- Outer border: the posterior border of the sternocleidomastoid muscle, marking the lateral neck line
6.2 Marking the Forbidden Treatment Areas:
① The bony orbit including the upper eyelid and eyeball region.
② The anterior midline of the neck from below the cricoid cartilage to above the sternal notch, within the lateral edges of the trachea (especially avoiding the Adam’s apple, vocal cords, and thyroid area).
③ Areas with dense nerve distribution, such as the infraorbital foramen, mental foramen, supraorbital foramen or notch, greater auricular nerve below the ear, and the trigeminal nerve area in front of the ear.
④ A finger’s width (1.5 cm) outward from the front of the ear and a finger’s width inward from the mouth corner.
⑤ Depressed facial areas, such as the cheek depression and temporal depression areas.
⑥ The bony lower edge of the mandible.
6.3 Treatment Reference Parameters:
Treatment Operation Standards
Treatment Handpiece Usage
- The same depth of knife head mode is more effective than the cannon head mode.
- 4.5mm treatment head
- Suitable for: Deep treatment of the cheek area with thicker tissue and below the mandibular margin.
- Not suitable for: Around the eyes, forehead, below the upper edge of the thyroid, temple, and areas with obvious depressions of the zygomatic arch.
- 1.5mm treatment head
- Suitable for: Forehead, face, and neck areas except for prohibited zones.
- 2.0mm treatment head
- 3.0mm treatment head
- Selection depends on the patient’s facial fatness or thinness and local tissue thickness.
- 4.5mm treatment head
Treatment Process
- Upper third of the face
- Forehead, supraorbital area, lateral canthus, infraorbital area.
- Treatment head: 2.0mm or add 1.5mm.
- Energy setting: Middle or slightly lower level.
- The 1.5mm treatment head should be 1–2 levels lower than the 2.0mm head.
- Treatment lines: 30–50 lines per side for each treatment head.
- Shots: Cannon head emits 150–200 lines per side.
- Forehead, supraorbital area, lateral canthus, infraorbital area.
- Middle and lower face, cheek area
- Treatment head: 1.5–4.5mm heads can be used (except prohibited areas and particularly thin patients).
- Energy setting:
- 4.5mm and 3.0mm heads: energy at the upper limit or 1–2 levels below the upper limit.
- 2.0mm and 1.5mm heads: 1–3 levels below the middle energy level.
- Treatment lines (per half-side of the face):
- 4.5mm head: 100–200 lines.
- 3.0mm head: 100–200 lines.
- 2.0mm head: 50–100 lines.
- 1.5mm head: 50–100 lines.
- Shots: 200–400 lines per cannon head per side.
- Neck area
- Treatment head: 1.5–2.0mm heads.
- Energy setting:
- 2.0mm head parameters: in the lower-middle range, 20–50 lines per side.
- 1.5mm head parameters: even lower energy, 20–50 lines per side.
- Shots: 700–800 lines per side.
7. Key Micro-Focused Ultrasound Operating Techniques and Peri-Treatment Scientific Management Protocols
7.1 General Principles and Key Points:
Treatment Principles
Prohibited Treatment
- Vocal cords and thyroid areas.
Avoid high-energy treatment with 3.0mm or deeper treatment heads in areas with concentrated nerve branches
- Infraorbital foramen, zygomatic foramen, supraorbital notch, trigeminal nerve area in front of the ear, and great auricular nerve area.
Areas with obvious local depressions should not be treated with 3.0mm or deeper treatment heads.
Combined Treatment with Cartridge and Bullet Heads
- For areas with thick or bulky subcutaneous fat:
- First use the 4.5mm treatment head, followed by the 3.0mm head for fat reduction and tightening.
- Then, use the 2.0mm and 1.5mm treatment heads for further treatment.
- For areas with tissue laxity and sagging but not bulky:
- Use the 3.0mm, 2.0mm, and 1.5mm heads, focusing on fat reduction.
- For areas with thin skin:
- Use the 2.0mm and 1.5mm treatment heads.
- Avoid using 3.0mm or deeper treatment heads.
- For areas with significant bulkiness and sagging:
- Increase the energy or number of treatment shots for the 4.5mm and 3.0mm heads.
Combined Use with Medications
- Before applying the coupling agent, introduce the medication to be delivered.
- After the conventional treatment ends, use the bullet head with low energy plus the medication for enhanced delivery.
Treatment Sequence
- From deep to superficial layers, from bottom to top, and from outside to inside.
Keep the probe in close contact with the skin and work in an orderly, linear fashion.
Do not lift the probe from the skin before completing the treatment line.
In areas with significant skin laxity, lift and reposition the skin before treatment.
Initial treatment areas can be appropriately retreated to enhance the effect.
Key Operational Points
- Cartridge head treatment: Keep the treatment head fixed and stationary during energy emission (“fixed and stable” principle).
- Bullet head treatment: Follow the principle of “moving and not fixed,” starting slowly and then speeding up.
For the 4.5mm treatment head, only apply gentle pressure so that the treatment surface is flush with the skin. Avoid excessive pressure.
- Particularly for thinner clients, be cautious in areas with thin subcutaneous tissue, such as near the jawline, infraorbital foramen, and alveolar regions.
Energy levels for the 1.5mm and 2.0mm treatment heads should not be too high, and the treatment handle must be pressed firmly to ensure full contact between the treatment head and skin.
7.2 Peri-treatment Management Plan
7.2.1 Treatment Areas:
Avoid direct treatment over bony margins. If the patient experiences numbness or excessive pain during deep-layer treatment, stop treatment in that area immediately and closely monitor to avoid nerve injury or skin burns.
7.2.2 Communication and Comfort Management:
① Maintain interactive communication with the patient, asking about any aching or discomfort sensations;
② Inform the patient in advance about the potential for soreness, swelling, or tingling sensations;
③ Adjust the energy level based on the patient’s feedback to reduce pain and discomfort;
④ For patients who cannot tolerate the pain, consider giving oral pain medication 30 minutes before the treatment.
7.2.3 Treatment Outcome Evaluation Standards:
Take standardized photos before and after treatment as a routine practice. If needed, use the Fitzpatrick Wrinkle Scale or VISIA imaging analysis for assessment.
Interval Time
3.0mm and 4.5mm Treatment Heads
- Tightening and Anti-Aging: Treatment once every year
- Low Energy, Fewer Treatment Shots: Treatment once every 4 to 6 months
1.5mm and 2.0mm Treatment Heads
- Every 2 to 3 Months: Once
- Skin Quality, Pores Improvement, and Maintenance Treatment: Once every 4 to 5 weeks
7.2 Peri-treatment Management Plan
7.2.1 Treatment Area:
Avoid direct treatment along bony ridges. If the patient experiences numbness or excessive pain during deep-layer operations, immediately stop treatment in that area and closely monitor to prevent nerve injury and skin burns.
7.2.2 Communication and Comfort Management:
① Maintain active communication with the patient, inquiring about sensations of soreness or discomfort;
② Inform the patient in advance of the possible sensations of soreness, swelling, or tingling;
③ Adjust energy settings based on patient feedback to reduce pain and discomfort;
④ For patients who have low pain tolerance, consider oral pain medication 30 minutes before treatment.
7.2.3 Treatment Effectiveness Evaluation Criteria:
Conduct standardized photography before and after treatment. If necessary, evaluate using the Fitzpatrick Wrinkle Scale or VISIA imaging analysis.
7.3 Treatment Interval Time
The interval between treatments should be at least 3 to 6 months, depending on the patient’s condition and skin recovery status.
7.4 Post-Treatment Daily Care:
Use medical cold compresses to moisturize and repair the skin. Practice strict physical sun protection. Avoid high-temperature environments within 48 hours. Refrain from using products containing retinoic acid or fruit acids.
8.1 General Complications:
The general complications of micro-focused ultrasound treatment include temporary erythema (redness), slight swelling, mild to moderate tenderness or soreness, and transient localized numbness. These symptoms typically resolve on their own within a few hours to a few days after treatment.
General Complications
- Skin redness and swelling
- Symptoms: Mild and transient
- Recovery time: Typically resolves within 2 to 7 days
- Treatment: External application of a repair mask once daily
- Bruising and skin pigmentation changes
- Symptoms: Transient
- Treatment: Anti-pigmentation treatments
- Masseter muscle or jaw soreness
- Symptoms: Generally transient
- Duration: Usually 2 to 3 days; in severe cases, up to 7–10 days
- Treatment: Generally no special treatment needed
- Neuropathic pain, numbness of the jaw, etc.
Severe Complications
- Local burns
- Preventive measures: Prepare ice packs before treatment and closely monitor during the procedure. If papules or vesicles or linear skin elevations appear, stop treatment immediately and apply local cold compresses.
- Treatment measures: Use corticosteroid ointments or burn treatments.
- Nerve injury
- Preventive measures: Control energy levels and maintain standardized operation to avoid nerve injury.
- Treatment measures: Use vitamin B12, corticosteroids, and neurotrophic agents.
- Eye injury
- Preventive measures: Emphasize standardized operation and focus on prevention to avoid eye injuries.
These measures aim to reduce the risk of serious side effects during treatment and ensure the safety and effectiveness of the procedure.
The consensus is intended solely for reference. In actual clinical application, especially regarding energy and parameter settings, personalized adjustments should be made based on the specific conditions of the patient and the brand of equipment used.
