Acne scars remain among the most challenging problems in aesthetic dermatology: even with noticeable cosmetic improvement, complete restoration of the original skin texture is not always achievable. In practice, the specialist must constantly balance the depth and intensity of the treatment (to trigger dermal remodeling) against the risks of complications and downtime, which are particularly critical for patients with darker skin types. In this context, technologies that deliver energy to the dermis while maximally sparing the epidermis are of great interest.

A preliminary study on the efficacy and safety of a single treatment using high-intensity, high-frequency, non-focused ultrasound parallel beams for the correction of acne scars in Asian patients was published in the Journal of Cosmetic Dermatology [1]. The authors examine Synchronous Ultrasound Parallel Beam (SUPERB) technology, in which several synchronized ultrasound transducers generate parallel beams that create multiple cylindrical volumetric zones of controlled thermal injury within the dermis.

Technology Essence and Biophysical Effects

According to the article [1], high-intensity, high-frequency ultrasound parallel beams penetrate the mid-dermis to a depth of approximately 0.5–2 mm, with a central focus at 1.5 mm. This layer is rich in collagen and elastin fibers; local heating at 60–70°C induces partial denaturation, which subsequently triggers neo-collagenesis, neo-elastinogenesis, and extracellular matrix (ECM) remodeling. The article emphasizes that the device used features integrated cooling and real-time skin temperature monitoring, which should reduce the risk of thermal damage to the epidermis.

The synchronicity and "parallelism" of the beams are technologically significant. In the discussion, the authors state that the handpiece is equipped with seven parallel transducers that activate simultaneously with each pulse, ensuring broader tissue coverage [2]. They also provide a coverage guideline: according to in vivo histological analysis, two passes with a 50% overlap effectively cover approximately 28% of the mid-dermal layer [2]. For the practitioner, this means the effect is produced by multiple distributed thermal zones in the target rather than by single points of heating [2].

Indications and Patient Selection: Insights from the Source

The study was conducted on patients with mild to moderate acne scars located on the cheeks and/or temples. In the introduction, the authors remind us that atrophic scars (ice pick, boxcar, rolling) form due to collagen loss and inadequate ECM remodeling following inflammatory acne lesions, clinically manifesting as skin depressions.

The article formally outlines inclusion/exclusion criteria that define the scope of the findings. Included were males and females aged 22–80 years who received a single treatment and had complete records with at least one follow-up visit and 2D/3D imaging data. Excluded were patients with any cosmetic treatments in the target area before follow-up; those with severe solar elastosis, chronic drug or alcohol abuse, or usage of anticoagulants/antiplatelet drugs; pregnant or breastfeeding women; and those with any condition that might make participation unsafe. These are not universal contraindications for all patients; rather, they are situations for which this specific study provides no data.

Treatment Protocol: Parameters and Procedure

All participants underwent a single full-face treatment and were followed for up to 8 months. Before the procedure, patients cleansed and dried their skin; ultrasound gel was used as a coupling medium, and air cooling was applied for pain relief; no topical anesthesia was used.

The transducers operated at 10–12 MHz with a depth of 1.5 mm. The pulse duration was 5 s, followed by 1–3 s of post-cooling. energy ranged from 3.4 to 4.21 J, depending on the area and tolerance, and the procedure lasted 45–60 minutes. The protocol provides guidelines by zone: forehead 3.4 J/pulse (40–50 pulses per side, 1 pass), periorbital area 3.4–4.2 J (10 pulses, 2 passes), cheek 3.8–4.2 J (100–120 pulses, 2–3 passes). Post-treatment erythema and edema were expected to resolve spontaneously; patients were instructed to report any side effects. No restrictions on daily activities were imposed.

Design and Clinical Results for Acne Scars

The work was designed as a retrospective observational study: data were collected from 14 Thai subjects (9 females, 5 males) aged 24–55 years, with Fitzpatrick skin types II–IV. Regarding baseline scar severity (ASS scale): 14.3% were grade 1, 42.9% grade 2, and 42.9% grade 3. Analysis included the cheek (12) and temple (4) areas. The average follow-up time was 3.6 months, with a maximum of 8 months.

The key quantitative tool was Antera 3D analysis: depression volumes were measured at three levels based on lateral size ranges: small (0.1–1 mm), medium (0.1–2 mm), and large (0.1–3 mm). Results were evaluated relative to baseline (100%): any value below 100% was considered an improvement. According to the authors, the mean reduction in depression volume was statistically significant across all three categories: small and medium by an average of 27%, and large by an average of 23%. No significant differences were found among the three depression levels, which the authors interpret as indicating comparable effects across the measured depths/sizes.

Qualitative assessment also favored improvement. According to PGAIS, all treated areas showed improvement: 47% were graded as "marked improvement" and 33% as "very much improved." According to the ASS scale, 64% of treated areas improved; notably, all areas graded "severe" at baseline were regraded "mild" or "moderate" at follow-up. The article cites an example of a 33-year-old female: in the temple area, the volume of "large depressions" decreased from 12.29 to 4.20 mm³ (65.8% improvement) at the 2-month follow-up. The authors note that the temple region is often difficult to correct due to soft-tissue volume loss and report interesting results for boxcar-type scars in this zone [3].

Safety and Tolerability

The mean pain level during treatment was 3.94±0.77 on an 11-point scale (0–10). No adverse events were recorded during the study period. In the discussion, the authors compare this with data on complications from microfocused transcutaneous ultrasound, in which events such as post-inflammatory hyperpigmentation, burns, and nerve injury have been reported, emphasizing that no such events occurred in their series at energy levels up to 4.2 J [4]. They also note that the result was achieved after a single treatment, whereas the literature on microfocused ultrasound for acne scars more often reports protocols with multiple sessions [5].

Limitations and Future Perspectives

The authors explicitly state the limitations: small sample size (n=14), retrospective nature, varying follow-up durations, and a relatively short average follow-up of 3.6 months (maximum 8 months). Additionally, it is important to note that patients initially sought the procedure for "skin tightening," and the improvement in scars was essentially an incidental finding evaluated retrospectively. Therefore, the authors suggest that future studies should target scar areas specifically, expand the cohort, conduct prospective randomized trials, include biopsy data to confirm neocollagenesis, and extend follow-up to 12–18 months to assess the durability of the effect and the risk of late-onset complications.

Practical Value: Interpreting the Data

From a practical standpoint, the article provides three pillars. First, a clear target depth: the mid-dermis (approx. 1.5 mm), and a mechanism involving controlled thermal zones that induce partial collagen/elastin denaturation and subsequent remodeling [2]. Second, preliminary clinical efficacy for atrophic acne scars in skin types II–IV after a single treatment: an average 23–27% reduction in depression volume by 3D metrics and consistent improvement in PGAIS/ASS. Third, tolerability in the described series: moderate pain without anesthesia and an absence of recorded adverse events during up to 8 months of follow-up.

However, the level of evidence remains preliminary: there is no control group, the sample size is small, and the design is retrospective. Therefore, it is most accurate to view SUPERB as a promising non-invasive dermal remodeling tool for atrophic acne scars that requires confirmation in more rigorous studies and does not replace the need for individualized strategy selection and combination methods.

References

1. Boonchoo K., Hongcharu W. The efficacy and safety of a single treatment of high-intensity, high-frequency, non-focused ultrasound parallel beams for facial acne scars in Asian patients: a preliminary study. J Cosmet Dermatol. 2025; 24: e70134. https://doi.org/10.1111/jocd.70134
2. Wang J.V., Ferzli G., Jeon H. et al. Efficacy and safety of high-intensity, high-frequency, parallel ultrasound beams for fine lines and wrinkles. Dermatol Surg. 2021; 47(12): 1585–1589.
3. Rose A.E., Day D. Esthetic rejuvenation of the temple. Clin Plast Surg. 2013; 40(1): 77–89.
4. Friedmann D.P., Bourgeois G.P., Chan HHI, et al. Complications of microfocused transcutaneous ultrasound: a case series and a review of the literature. Lasers Surg Med. 2018; 50(1): 13–19.
5. Maas C.S., Joseph J.H. Safety and effectiveness of microfocused ultrasound with visualization for the correction of moderate to severe atrophic acne scars. J Drugs Dermatol. 2019; 8(11): 1109–1114.