Post-traumatic atrophic scars are characterized by skin depressions caused by loss of collagen and can lead to cosmetic and psychological concerns. Several treatment options have been proposed, including fractional carbon dioxide (CO2) laser resurfacing and autologous nanofat grafting, both of which may improve scar appearance through skin remodeling and regeneration. This prospective comparative study evaluates the safety and efficacy of fractional CO2 laser alone, autologous nanofat injection alone, and combination therapy in patients with post-traumatic atrophic scars. Sixty participants were assigned to one of three treatment groups and were assessed using the Vancouver Scar Scale, physician global assessment, patient satisfaction, dermoscopic examination, and histopathological evaluation. The study aims to determine whether combining fractional CO2 laser and nanofat injection provides superior clinical and regenerative outcomes compared with either treatment alone while maintaining an acceptable safety profile.

Post-traumatic atrophic scars are characterized by dermal collagen loss, epidermal thinning, and alterations in skin texture and pigmentation. These scars may result in significant cosmetic disfigurement and negatively affect patients' quality of life. Despite the availability of multiple treatment modalities, no single intervention has consistently demonstrated optimal efficacy.

Fractional carbon dioxide (CO2) laser induces controlled microthermal injury that stimulates collagen remodeling and skin regeneration. Autologous nanofat grafting, which is rich in adipose-derived regenerative cells and growth factors, has emerged as a promising regenerative treatment for improving skin quality and scar remodeling. Combining these two modalities may provide synergistic effects by enhancing tissue regeneration and improving both structural and aesthetic outcomes.

This prospective comparative study was conducted to evaluate and compare the safety and efficacy of fractional CO2 laser monotherapy, autologous nanofat injection monotherapy, and combination therapy in the treatment of post-traumatic atrophic scars. Clinical efficacy was assessed using physician evaluation, Vancouver Scar Scale scores, and patient satisfaction, while dermoscopic and histopathological examinations were performed to investigate treatment-induced structural changes and the mechanisms underlying scar improvement.

The study aimed to determine whether combined therapy offers superior clinical and regenerative outcomes compared with either treatment alone while maintaining an acceptable safety profile.

Inclusion Criteria:

• Male or female participants aged 12 years or older.
• Presence of post-traumatic atrophic scar(s) of at least 6 months' duration.
• No scar treatment received during the previous 6 months.
• Willingness and ability to provide written informed consent (or assent with -parental/guardian consent for minors, according to local regulations).
• Willingness to comply with study procedures and follow-up assessments.

Exclusion Criteria:

• Hemoglobin <10 g/dL.
• Active infection or viral skin disease.
• Coagulopathy or hemophilia.
• Current anticoagulant therapy.
• Diabetes mellitus.
• History of keloid formation.
• History of malignancy or prior radiation therapy.
• Immunosuppression.
• Long-term systemic corticosteroid therapy.
• Photosensitivity disorders.
• Pregnancy or breastfeeding.
• Renal or hepatic disease.
• Systemic diseases affecting wound healing.
• Thin patients with insufficient adipose tissue for adipose tissue harvesting.
• Previous scar treatment within the preceding 6 months.
• Use of systemic retinoids within the preceding 6 months. -Use of topical retinoids within the preceding 2 weeks.-

Individual participant data will not be shared publicly because participant consent for public data sharing was not obtained and the dataset contains potentially identifiable information.