Prospective Study of Three-Dimensional Bi-directional Barbed Threads for Midface and Nasolabial Fold Rejuvenation

Background: Thread lifting is a minimally invasive procedure using absorbable sutures like polydioxanone (PDO) to provide immediate lifting and stimulate collagen for long-term skin rejuvenation. This prospective study evaluates the safety and efficacy of Croquis® Barbed Cutting PDO threads, featuring a unique 3D bi-directional barb design, in enhancing facial lifting outcomes. Methods: Thirty participants with Wrinkle Severity Rating Scale (WSRS) scores of 3 or 4 underwent midfacial lifting using 3D bi-directional barbed PDO threads (Croquis®, Samyang Holdings Corporation, Korea) between June 2023 and February 2024. Outcomes were assessed at 1, 3, and 6 months using 3D imaging (LifeViz®, Quantificare, France). Efficacy was evaluated by both investigators and patients using the WSRS and the Global Aesthetic Improvement Scale (GAIS). A generalized estimating equation (GEE) model was used to identify associations between covariates and outcomes. Results: Thirty female patients (mean age, 58.0 ± 5.6 years) were included. WSRS scores significantly decreased over time, from 2.33 ± 0.12 at 1 month to 1.47 ± 0.09 at 6 months (p < 0.001), indicating sustained wrinkle reduction. Investigator-assessed GAIS also improved significantly at 6 months compared with 1 and 3 months (p < 0.01), while patient-assessed GAIS showed a gradual improvement, reaching significance between 3 and 6 months (p = 0.010). Multivariable analysis confirmed that time and thread number were significant predictors of WSRS and investigator GAIS improvement, whereas age, BMI, and comorbidities had no effect. No major complications occurred, and only minor, self-limiting adverse events such as bruising were observed. Conclusions: 3D bi-directional PDO threads demonstrated safety and efficacy for midfacial rejuvenation, producing sustained wrinkle reduction and investigator-rated aesthetic improvement at 6 months. While a paired comparison with other thread types would have provided stronger evidence, ethical and technical limitations precluded direct contralateral-thread trials. These prospective data nonetheless contribute objective evidence to a field largely informed by retrospective or anecdotal reports. Level of Evidence V: 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.