Evaluating the Long-term Effects of Microfocused Ultrasound on Facial Tightening Using Quantitative Instruments:...

Microfocused ultrasound (MFU) is a non-invasive technique used for facial rejuvenation, yet there is limited quantitative data on its long-term effects. This study aimed to evaluate the long-term efficacy and safety of MFU for facial rejuvenation. We utilized standardized photography along with advanced skin assessment technologies to analyze the impact of MFU on facial morphology, skin function, and patient satisfaction over a 12-month period.

A prospective clinical study was conducted on 28 healthy female subjects (age range: 33-55 years) who underwent a single MFU treatment. Comprehensive assessments were performed at baseline and at seven follow-up time points (30 minutes, 1 week, 1 month, 3 months, 6 months, 9 months, and 12 months). Objective measurements included facial volumetric changes nasolabial fold morphology, skin physical parameters, and clinical aesthetic scores. Patient satisfaction and safety data were also collected.

Longitudinal data were analyzed using linear mixed-effects models with subject-specific random intercepts to account for repeated measurements.

Facial volume showed significant immediate increase (5.65 ± 2.15 ml, 95% CI: 4.821-6.486, CV=37.98%, P < 0.001, Cohen's d = 2.633) post-treatment, followed by progressive tightening, with maximum volume reduction at 3 months (- 3.37 ± 4.79 ml, 95% CI: - 5.227 to - 1.511, CV=142.26%, P < 0.001, Cohen's d = - 0.703). Both facial and submental regions maintained statistically significant volume reduction through 12 months: Facial region: - 1.86 ± 4.72 ml (P = 0.048, Cohen's d = - 0.39); Submental region: - 1.26±2.22 ml (95% CI: - 2.118 to - 0.394, P < 0.05, Cohen's d = - 0.565),with the submental region demonstrating superior durability. The nasolabial fold region, volume, and maximum depth demonstrated the greatest improvement at 3 months (depth reduction: 0.28 ± 0.08 mm, p < 0.001), with 'wide-short' morphological subtypes exhibiting superior efficacy compared to 'narrow-long' subtypes (P < 0.05). Skin ultrasound collagen intensity showed progressive improvements, peaking at 9 months ( + 10.08 a.u., 95% CI: 7.73-12.44, P < 0.001, Cohen's d = 1.54) and remained significantly elevated at 12 months with a 9.03 a.u. increase (95% CI: 6.49 to 11.58, P < 0.001, Cohen's d = 1.38). Treatment induced significant, sustained increases in skin hydration (mean + 50.5-55.8 μS; p < 0.05; Cohen's d 0.79-1.06) from 30 minutes through 6 months, with effects becoming non-significant at 9 months (+ 36.4 μS) and returning to baseline by 12 months. Transepidermal water loss (TEWL) decreased significantly from 1 month through 9 months, with peak improvement at 6 months (- 3.05 g/m²/h, 95% CI: - 5.39 to - 0.71, P < 0.05, Cohen's d = - 0.54). GAIS scores peaked at 3 months (physician rating: 3.48 ± 0.48; patient rating: 3.75 ± 0.44) with strong inter-rater correlation (r = 0.728, P < 0.001) and 89.2% of patients willing to undergo retreatment. Adverse events were mild and transient, limited to erythema (67.9%) and edema (28.6%) resolving within one week.

MFU facial rejuvenation demonstrated a time-dependent efficacy profile, with peak improvements observed at 3 months and substantial benefits maintained at 9-12 months. Treatment response varied anatomically, showing most durable submental improvement. Nasolabial fold morphological subtypes significantly influenced efficacy, with 'wide-short' morphology correlating with superior outcomes. The procedure provided significant rejuvenation with minimal downtime, high patient satisfaction and an excellent safety profile. Level of Evidence III This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 . Trial Registrations This trial is registered with ChiCTR2400093439 (China) and NCT06286384 (ClinicalTrials.gov).