Comparative study between therapeutic effects of microneedling versus CO₂ laser in acne scars

Introduction

Acne, a common inflammatory condition of the pilosebaceous unit, is characterized by comedones, papulo-pustules, and occasionally nodules. It mostly affects the face, followed by the chest and back. Remaining scarring is a usual adverse effect of acne treatment. Acne scarring can negatively affect quality of life, leading to low self-esteem and unpleasant feelings.¹

Severity of the residual scarring depends on the duration and intensity of the inflammatory response during the active disease. There is weakening of the collagen synthesis caused by an increased ratio of tissue inhibitors of MMPs to matrix metalloproteinases (MMPs) during the extracellular matrix remodeling process.²

A classification system has been described to segregate atrophic scars post acne into three types: icepick, rolling, and boxcar scars. With the help of this classification, treatment options can be better tailored to each individual patient.¹Ice pick scars being less than 2 mm in diameter that extend vertically through the whole length of dermis. Boxcar scars are spherical skin depressions with flat bases and sharp edges that could be shallow (0.1-0.5 mm) or deep (>0.5 mm). Lastly, rolling scars are depressions which range in size from 4 to 6 mm and are shallower than boxcar type but have the largest circumference. The aberrant fibrous bands causing these scars pull the dermis down to attach to the subcutaneous layer.²

Microneedling is a commonly used minimally invasive technique used to treat acne scars. It involves creating skin punctures using sterile micro needles attached to a handheld rolling device which helps in disrupting dermal collagen fibers that connect the scar tissue. Growth factors are regenerated as a result, encouraging the dermal blood vessels to produce collagen and elastin.³ Microneedling works best for healing shallow boxcar and rolling scars since it only reaches the upper dermis.¹ Fractional ablative CO₂ lasers, which have only recently as of 2003 hit the market, are an efficient method of managing acne scars with least adverse effects. They work on the principle of fractional thermolysis. This refers to the creation of pixilated columnar zones of thermal injury to the dermis also known as micro thermal zones in order to promote collagen formation.⁴

The fractional component of the laser makes sure that the tissue injury is spatially well distributed in a precise pattern across the treated area, while retaining the healing function of the epidermis whereas the ablative component ensures fewer side effects, such as erythema, edema, hemorrhage, crusting, infection, and scarring since they target the dermis while leaving the epidermis intact.⁵

In carbon lasers, water acts as a chromophore which produces light at a wavelength of 10,600 nm. Due to the significant tissue water absorption of the carbon dioxide beam, depth penetration is limited. However, depths of over 2 mm can be reached by increasing irradiation over a very small region in a fractionated method and employing greater pulse energies. In addition to modifying dermal collagen, development of myofibroblasts and matrix proteins like hyaluronic acid is also aided by carbon dioxide lasers. Matrix metalloproteinases are present at exceptionally high concentrations promoting wound healing (MMPs).⁶

Therefore, by comparing the outcome between these two commonly used treatment modalities, we can have knowledge as to which intervention would be most effective in acne scar management.

Protocol

Methods

Methods

Prospective comparison is used as the method in this study in which 100 patients having acne scars coming to the Department of Dermatology at AVBRH, Wardha, will be enrolled after considering the various exclusion and inclusion criteria’s from June 2021 to June 2023. Institutional Ethical Committee (IEC) clearance will be been obtained. Written and signed informed consent in their vernacular language will be taken from all the participants for voluntary participation. A detailed history including name, age, sex, past history and family history will be taken. A detailed clinical examination will be performed for all patients presenting with post acne atrophic scars.

Based upon the severity of acne scars, patients will be classified into four grades according to the “Goodman and Baron Qualitative scar grading system” (Table 1).⁹ The patients will be split into two groups with 50 patients each, Group A and Group B. Participants will be randomly assigned to either groups with a 1:1 allocation as per a computer generated randomisation schedule stratified by site and using permuted blocks of random sizes. The block sizes will not be disclosed, to ensure concealment. The group A will be selected for fractional ablative CO₂ laser using Futura CO₂ Fractional Laser System®. The group B will be selected for microneedling using the Dermapen 4^TM. Four treatments will be given to patients in both groups, with a four-week interval between each session. There will be a clinical evaluation of the progress made based on “Goodman and Baron Qualitative scar grading system” at the end of each session by a side by side comparison of pre-operative and post-operative photographs. All patients from both the groups will be prescribed a topical sunscreen and moisturizer post procedure. Additionally, one month following the fourth session, patients will be questioned regarding how scars have improved in order to determine patient satisfaction using the Visual Analogue Score (VAS). In order to improve adherence of patients to the study, patients will be counselled in detail about the procedures and the improvement they can expect with successive therapies. A thorough follow up shall be done using patients contact information collected during the enrollment process along with adjusting dates of treatment according to the patient’s comfort. During the period of the study, patients will not be receiving any concomitant therapy for their acne scars in order to prevent bias in the therapeutic effects of the modalities being compared in the study. Both treatment interventions shall be discontinued in case of any adverse reaction or worsening of existing lesions. The time schedule of enrolment, interventions, assessments, and visits for participants has been explained in the participant timeline figure (Table 2). The progress of the study will be monitored by the departmental committee headed by the Head of the Department of Dermatology.

Discussion

Bhalla M, Arora A, in the year 2022, studied the role of fractional CO₂ lasers in acne scars and found that fractional carbon dioxide lasers showed effectiveness in skin renewal in atrophic acne scars. They explained the mechanism by which fractional lasers work and the proper treatment protocol to be followed for best results. They concluded that counselling, patient selection with pre and post procedure care guidelines are crucial factors upon which the treatment outcome depends.⁶ Jordan R, Cummins C et al., in the year 2000, carried out research to determine how laser resurfacing can reduce the appearance of face acne scars. They discovered that the patient efficacy ranged from 25 to 90% for both the carbon dioxide laser and the erbium: YAG laser. Although lasting a few weeks, pigmentation changes as a side effect were experienced by up to 44% of individuals. After receiving the carbon dioxide laser, patients experienced erythema for 1.5 to 4 months before re-epithelialization occurring after 7 to 14 days. Up to 84% of individuals can expect their acne or milia to return. It was discovered that the likelihood of serious consequences, such as hospitalization because of a systemic infection, was quite low. They arrived to the conclusion that high-quality randomized controlled studies with standardized scarring scales and validated patient outcome measures are needed to assess the effectiveness of laser resurfacing.¹⁰

In the year 2012, Levy LL, Zeichner JA, et al. discussed and analyzed the various minimally invasive methods for treating acne scarring with a focus on pharmacologic agents, such as isotretinoin for acne scars that are atrophic and corticosteroids with chemotherapeutic drugs for scars that are hypertrophic. They discuss various in office and minimally invasive techniques like chemical peels, dermabrasion, tissue augmentation, and punch excision. They conclude that no single strategy has emerged as first line as we must individualize the treatment in accordance with the type of acne scars present. Moreover, they emphasize on managing patient expectations and setting realistic goals. They also suggest a combinational approach with lasers in order to achieve best results thereby improving patient’s quality of life.¹¹

Zaleski-Larsen LA, Fabi SG et al., in the year 2016, conducted a research to examine the efficacy and safety of combining multiple modalities in the treatment of acne scars. Results of the hyaluronic acid filler were discovered to be evident immediately and to continue to stimulate neocollagenesis for a period of 12 to 24 months. With fat transplantation, optimal effects were typically seen 3 months after the procedure. Treatment options for 45 individuals with atrophic acne scars included skin needling combined with PRP, 100% TCA CROSS, and PRP. Improvement was found in 46.7%, 26.7% and 60% of the patients respectively. Non-ablative fractional lasers with 20% TCA improved atrophic acne scars by 78.27%. Autologous bone marrow stem cells were administered to 14 patients and implanted beneath the acne scars. At six months after the surgery, the acne scars had significantly improved. CONCLUSION: Combining acne scar treatment techniques is safe and leads to optimal patient outcome.¹²

To evaluate the efficacy of fractional CO₂ laser and fractional radiofrequency microneedling in the treatment of facial acne scars, Reddy KY, Swaroop R et al. did a study in 2020. According to the findings, 20% of patients in the MnRF group had improved by three grades one month following their final session, compared to 13.3% of patients in the fractional CO₂ group.¹³