Simultaneous Versus Sequential Fractional CO2 Laser and Subcision Combination for Post-acne Atrophic Scars: A Split-face Comparative Study.

Summary

Acne vulgaris, a disease of the pilosebaceous unit, is estimated to afflict 9.4% of the global population, making it the eighth most prevalent and third most significant disease according to the global burden of disease. Post-acne atrophic scars may develop in 95% of acne patients due to aberrant wound healing that affects the pilosebaceous unit and surrounding tissue. Scars are cosmetically unattractive, contributing to the severe psychosocial discomfort observed in acne vulgaris patients.

Several approaches exist for the treatment of post-acne atrophic scars, depending on various factors such as the individual's condition, the types of scars present, and the associated expenses. However, treating atrophic acne scars remains challenging for physicians because there is no gold-standard treatment. Thus, combinations of interventions are typically necessary.

Fractional CO2 laser and subcision are therapeutic methods proven to be effective in treating post-acne atrophic scars. By creating hundreds of thousands of micro-heat treatment zones (MTZs), fractional CO2 lasers emitting small focal spots (50-80 m) via high-focusing mirrors can efficiently treat acne scars. These thermal damage columns accelerate the healing process of collagen synthesis. Subcision, which can be safely paired with other operations, should be the initial step in treating acne scars since it separates scars from underlying structures. Although several studies proposed that the combination of fractional CO2 laser and subcision was more efficacious than a single therapeutic modality, no study has to date compared the efficacy and safety of simultaneous versus sequential combination of these two methods in the treatment of post-acne atrophic scars. There is a critical need for basic research on the effectiveness and adverse events of combining modalities sequentially as compared to simultaneously due to the high expense of traveling and the downtime needed to recover after each treatment, especially for diseases requiring long-term and periodic intervention such as post-acne atrophic scars.

Wound healing is a dynamic process with four distinct but overlapping phases: hemostasis, inflammation, proliferation, and remodeling. The proliferation phase, during which new tissue is formed by a matrix of collagen, elastin, glycosaminoglycans, and other fibrous proteins, begins about four to twenty-one days following an injury. If sequential modalities interfere with each other's proliferative processes, therapeutic efficacy may be compromised. Therefore, our working hypothesis that simultaneous combination is more effective than sequential combination is based on the fact that if the wound-healing process is interrupted, it may stop or progress inadequately. In addition, the investigators anticipate no significant difference between these methods in terms of adverse events frequency and severity, but the downtime in the sequential combination group might be greater than that of the simultaneous combination group. The investigators propose to test the hypothesis by addressing the following two specific aims:

Aim 1: to compare the efficacy and patient satisfaction of simultaneous versus sequential treatment using fractional CO2 laser plus subcision.

Aim 2: To compare adverse reactions of simultaneous and sequential treatment using fractional CO2 laser plus subcision.

Upon completion of this study, the investigators will have (a) compared the treatment outcome of simultaneously versus sequentially combined fractional CO2 laser plus subcision based on ECCA clinical grading score, patient satisfaction, and skin thickness via high-frequency ultrasonography; and (b) compared the incidence and duration of adverse events in simultaneous versus sequential treatment. Optimizing the combination of different interventions will contribute to more efficacious and economical treatment protocols for post-acne atrophic scars.

Conditions

• Atrophic Acne Scar

Interventions

PROCEDURE

Simultaneous combination of fractional CO2 laser and subcision

Fractional CO2 laser is performed immediately following subcision. Subcision is operated in all participants using an 181/2G Nokor needle (BD Nokor™ Admix Needles, United States). The insertion depth is at the dermal-hypodermal junction. The subcision needle is advanced and retracted in a tunneling motion to penetrate the fibrotic scar tissue, then slid in a direction parallel to the skin's surface in order to detach the scar from its tethers. All participants undergo FrCO2 laser (10 600-nm eCO2 laser, Lutronic Corporation, Goyang, Korea) with the parameters following the suggested regimen at static mode: 120 μm beam size, 30 W peak power, 30 - 120 mJ pulse energy, 50-75 spots/cm2 density, with two passes: (1)Only the atrophic scars are treated using a 4mm square or circle pattern, 100-120 mJ pulse energy, and 50 spots/cm2 density. (2)The whole half side of the face is treated using a 12mm square pattern, 30-40 mJ pulse energy, and 75 spots/cm2 density, \<10% overlap.

PROCEDURE

Sequential combination of fractional CO2 laser and subcision

Fractional CO2 laser conducted two weeks after subcision. Subcision is operated in all participants using an 181/2G Nokor needle (BD Nokor™ Admix Needles, United States). The insertion depth is at the dermal-hypodermal junction. The subcision needle is advanced and retracted in a tunneling motion to penetrate the fibrotic scar tissue, then slid in a direction parallel to the skin's surface in order to detach the scar from its tethers. All participants undergo FrCO2 laser (10 600-nm eCO2 laser, Lutronic Corporation, Goyang, Korea) with the parameters following the suggested regimen at static mode: 120 μm beam size, 30 W peak power, 30 - 120 mJ pulse energy, 50-75 spots/cm2 density, with two passes: (1)Only the atrophic scars are treated using a 4mm square or circle pattern, 100-120 mJ pulse energy, and 50 spots/cm2 density. (2)The whole half side of the face is treated using a 12mm square pattern, 30-40 mJ pulse energy, and 75 spots/cm2 density, \<10% overlap.

DEVICE

Fractional CO2 laser

Fractional CO2 laser (10 600-nm eCO2 laser, Lutronic Corporation, Goyang, Korea) on both sides of the face sequentially with a two-week interval between sessions for each face's side by a single physician, with the parameters following the suggested regimen at static mode: 120 μm beam size, 30 W peak power, 30 - 120 mJ pulse energy, 50-75 spots/cm2 density, with two passes. At the first pass, only the atrophic scars are treated using a 4mm square or circle pattern, 100-120 mJ pulse energy, and 50 spots/cm2 density in the static operating mode. At the second pass, the whole half side of the face is treated using a 12mm square pattern, 30-40 mJ pulse energy, and 75 spots/cm2 density in the static operating mode with less than 10% overlap.

PROCEDURE

Subcision

Subcision is operated in all participants using an 1812G Nokor needle (BD Nokor™ Admix Needles, Becton, Dickinson and Company, New Jersey, United States). The operation sites are sterilized with alcohol pads and injected intradermally with a solution of 2% lidocaine. After obtaining appropriate anesthesia, a Nokor needle is inserted into the skin close to the depressed scars and progressed until it lays precisely under the scar. The insertion depth is at the dermal-hypodermal junction. Initially, the subcision needle is advanced and retracted in a tunneling motion to penetrate the fibrotic scar tissue. Once the fibrous mass has been sufficiently fractured, the needle is slid in a direction parallel to the skin's surface in order to detach the scar from its tethers. For densely fibrous scars, several needle insertion sites are used to undermine the defect from various angles.

DRUG

Lidocaine/Prilocaine 2.5%-2.5% Topical Application Cream

Preoperative, lidocaine 2.5% and prilocaine 2.5% cream (EMLA 5%, eutectic mixture of local anesthetic; AstraZeneca LP, Wilmington, DE, USA) is applied under occlusion for 60 minutes prior to the removal of local anesthetics

DRUG

Paracetamol

A 500 mg paracetamol-based oral analgesic (Efferalgan, Upsa SAS, France) is administered right before the procedure.

DRUG

Lidocaine 2% Injectable Solution

The operation sites are sterilized with alcohol pads and injected intradermally with a solution of 2% lidocaine.

Sponsors & Collaborators

• Ho Chi Minh City Hospital of Dermato-Venereology

  lead OTHER_GOV

Principal Investigators

• Quoc Bao Tran, Doctor · Ho Chi Minh City Hospital of Dermato-Venereology

Study Design

Allocation

NON_RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Model

FACTORIAL

Eligibility

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2022-10-24

Primary Completion

2023-09-12

Completion

2023-09-12

Countries

• Vietnam

Study Locations