Redefining scar quality: A synergistic approach with micro-needling and photodynamic therapy using methylene blue as a photosensitizer: a randomized clinical trial

Background

Hypertrophic and keloid scars are challenging to treat and can cause both aesthetic and functional problems. Traditional treatments such as laser therapy and corticosteroids have limited effectiveness and high recurrence rates. However, the emergence of photodynamic therapy (PDT) combined with micro-needling, especially when using methylene blue as a photosensitizer (PS) at different concentrations, offers a promising approach for scar treatment.

Objective

This study evaluates the effectiveness of combining PDT, micro-needling, and methylene blue at 1% and 0.1% concentrations to improve the quality of hypertrophic and keloid scars.

Methods

Novel Study Design: a randomized, double-blind clinical trial was conducted on 37 patients with 94 hypertrophic and keloid scars. Patients were divided into four groups based on scar type and methylene blue concentration. Each group underwent five treatment sessions, and scars were assessed using the Japan Scar Scale (JSS) and the Patient and Observer Scar Assessment Scale (POSAS).

Results

Significant Improvements: after five treatment sessions, we observed substantial improvements in various scar parameters. The Evaluation part of Japan Scar Scale (JSS) scores decreased from an average of 14.69 ± 2.81 at baseline to 4.69 ± 0.92 after six months, indicating a significant reduction in scar severity. The patient-observer scar assessment scale results show a notable improvement in Flexibility and thickness, with a 71% reduction in stiffness and a 69% reduction in pain. Overall, patient satisfaction increased by 60%, and visible improvements in pigmentation and vascularity were reported. The use of 1% methylene blue led to better outcomes than 0.1%, possibly due to enhanced light penetration and reactive oxygen species (ROS) generation. Importantly, no severe side effects were observed, and patient compliance remained high throughout the study.

Conclusion

Combining PDT and micro-needling using 1% methylene blue improves scar quality and prevents it from worsening, particularly for keloid scars. Further studies are recommended to confirm these findings and explore long-term effects.