Title: Possible Impact of Basic Characteristics of Acne Scar Patients on The Clinical Outcomes after Treatment with Monothreads

Background: Acne is a chronic inflammatory condition of pilosebaceous follicles, prevalent in adolescents and often leaving scars in over 80% of cases. Severe forms may cause permanent disfigurement and psychosocial distress. Thread lifting improve the appearance of acne scars with both immediate and long-term benefits. The aim of the study was to study the predictive value of basic characteristics of patients on the outcomes. Methods: Twenty-four patients with acne scars participated after IRB approval (Zagazig University, IRB 212/2024). After obtaining consent, a topical anesthetic cream was applied one hour before the procedure. Using sterile technique, 10-12 mono-threads were carefully inserted beneath atrophic scars in the dermis and dermo-subcutaneous junction to release fibrotic tissue and stimulate collagen production. Standardized pre- and post-treatment photographs were taken, and scar severity was evaluated before and after treatment using Goodman’s qualitative and quantitative global scarring grading system. Results: Female patients showed significantly greater improvement than males (p=0.029). Patients with previous scar treatment demonstrated higher recovery (median 50%) compared to untreated individuals (p=0.007). A history of isotretinoin use was associated with better outcomes, although the difference was not statistically significant (p=0.068). Scar type had an essential influence on the results (p=0.001): ice pick scars showed the most improvement, followed by rolling scars. Correlation analysis confirmed scar grading strongly predicted improvement (r=0.721, p<0.001). Conclusion: Clinical outcomes following mono-thread treatment are significantly influenced by sex, prior interventions, scar morphology, and severity, with baseline grading serving as the strongest predictor.