Energy-Based Skin Rejuvenation: A Review of Mechanisms and Thermal Effects

BACKGROUND

Energy-based photoelectric and ultrasonic devices are essential for skin rejuvenation and resurfacing in the field of plastic surgery and dermatology. Both functionality and appearance are impacted by factors that cause skin to age, and various energy types have variable skin penetration depths and modes of transmission.

AIM

The objective is to advise safe and efficient antiaging treatment while precisely and sensitively controlling and assessing the extent of thermal damage to tissues caused by different kinds of energy-based devices.

METHODS

A literature search was conducted on PubMed to review the mechanisms of action and thermal effects of photoelectric and ultrasonic devices in skin remodeling applications.

RESULTS

This paper reviews the thermal effects of energy-based devices in skin resurfacing applications, including the tissue level and molecular biochemical level. It seeks to summarize the distribution form, depth of action, and influencing factors of thermal effects in combination with the mechanisms of action of various types of devices.

CONCLUSION

Accurate control of thermal damage is crucial for safe and effective skin remodeling treatments. Thorough investigation of molecular biochemical indicators and signaling pathways is needed for real-time monitoring and prevention of severe thermal injury. Ongoing research and technological advancements will improve the accuracy and control of thermal damage during treatments.

Fractional 1064 nm Nd: YAG picosecond lasers for the treatment of traumatic scars: a retrospective study

Traumatic scars negatively impact the patient's quality of life. Fractional 1064 nm Nd: YAG picosecond laser improves scars. However, the effect varies among individuals. This study aimed to evaluate the treatment of traumatic scars with fractional 1064 nm Nd: YAG picosecond lasers and the factors associated with its prognostication. We conducted a retrospective study with 161 patients with traumatic scars. All scars were treated using fractional 1064 nm Nd: YAG picosecond lasers. Efficacy was determined based on blinded visual evaluation using the Manchester Scar Scale (MSS) and 5-point Global Assessment Scale (GAS). The mean MSS values before and after treatments was 17.4 ± 2.7 and 13.6 ± 2.6 (P < 0.001), respectively. Color, radiance, contour, and distortion of the traumatic scars improved. (all P < 0.001). The course, location, and height of the scars, and the number of treatments and energy densities, were related to treatment responses (P < 0.05). Fractional 1064 nm Nd: YAG picosecond laser is effective for treating traumatic scars. Clinicians can predict the prognosis using multiple factors.

A comparison of surgical scar treatment using various combinations of autologous fat, hyaluronic acid and resurfacing with the 1540 nm non-ablative Erbium laser - a prospective pilot study

Scars can cause aesthetic or functional disturbance. Several interventions had been described to improve their appearance. We propose that the combination of some of those treatments can synergize their effects on the scar. We designed a prospective pilot study with ten patients using the patient as their own control to compare different interventions. In each patient, the scar was divided into four parts treated differently: 1. No treatment (control), 2. Fat grafting only, 3. Fat grafting and Hyaluronic Acid (HA), 4. Fat grafting, HA and with a non-fractional laser. Each part of the scar was evaluated by the Patient and Observer Scar Assessment Scale (POSAS). Treatment of the scar with the combination of the three modalities showed better results in the observer scale. In addition, a combination of fat injection, HA, and subsequent skin resurfacing with non-ablative laser showed better outcomes for all parameters on the Observer Scale except vascularity, while on the Patient Scale thickness, relief, pliability, surface area, and overall measurement were better. The combination of all three treatments tends to improve scarring results and appears to be safe and effective. However, further studies with larger samples are needed to explore the potential use of this combined treatment.

Influence of scar age, laser type and laser treatment intervals on paediatric burn scars: a systematic review and meta-analysis

Background

Laser therapy has emerged to play a valuable role in the treatment of paediatric burn scars; however, there is heterogeneity in the literature, particularly concerning optimal timing for initiation of laser therapy. This study aims to investigate the effect of factors such as scar age, type of laser and laser treatment interval on burn scar outcomes in children by meta-analysis of previous studies.

Methods

A literature search was conducted across seven databases in May 2022 to understand the effects of laser therapy on burn scar outcomes in paediatric patients by metanalysis of standardized mean difference (SMD) between pre- and post-laser intervention. Meta-analyses were performed using the Comprehensive Meta-Analysis software version 4.0. Fixed models were selected when there was no significant heterogeneity, and the random effects model was selected for analysis when significant heterogeneity was identified. For all analyses, a p-value < 0.05 was considered significant.

Results

Seven studies were included in the meta-analysis with a total of 467 patients. Laser therapy significantly improved Vancouver Scar Scale (VSS)/Total Patient and Observer Scar Assessment Scale (Total POSAS), vascularity, pliability, pigmentation and scar height of burn scars. Significant heterogeneity was found between the studies and thus subgroup analyses were performed. Early laser therapy (<12 months post-injury) significantly improved VSS/POSAS scores compared to latent therapy (>12 months post-injury) {SMD -1.97 [95% confidence interval (CI) = -3.08; -0.87], p < 0.001 vs -0.59 [95%CI = -1.10; -0.07], p = 0.03} as well as vascularity {SMD -3.95 [95%CI = -4.38; -3.53], p < 0.001 vs -0.48 [95%CI = -0.66; -0.30], p < 0.001}. Non-ablative laser was most effective, significantly reducing VSS/POSAS, vascularity, pliability and scar height outcomes compared to ablative, pulse dye laser and a combination of ablative and pulse dye laser. Shorter treatment intervals of <4 weeks significantly reduced VSS/POSAS and scar height outcomes compared to intervals of 4 to 6 weeks.

Conclusions

Efficacy of laser therapy in the paediatric population is influenced by scar age, type of laser and interval between laser therapy application. The result of this study particularly challenges the currently accepted initiation time for laser treatment. Significant heterogeneity was observed within the studies, which suggests the need to explore other confounding factors influencing burn scar outcomes after laser therapy.

Effect of Laser and Energy-based Device Therapies to Minimize Surgical Scar Formation: A Systematic Review and Network Meta-analysis

Utilization of lasers and energy-based devices for surgical scar minimization has been substantially evaluated in placebo-controlled trials. The aim of this study was to compare reported measures of efficacy of lasers and energy-based devices in clinical trials in preventing surgical scar formation in a systematic review and network meta-analyses. Five electronic databases, PubMed, Scopus, Embase, ClinicalTrials.gov, and the Cochrane Library, were searched to retrieve relevant articles. The search was limited to randomized controlled trials that reported on clinical outcomes of surgical scars with treatment initiation no later than 6 months after surgery and a follow-up period of at least 3 months. A total of 18 randomized controlled trials involving 482 participants and 671 postsurgical wounds were included in the network meta-analyses. The results showed that the most efficacious treatments were achieved using low-level laser therapy) (weighted mean difference -3.78; 95% confidence interval (95% CI) -6.32, -1.24) and pulsed dye laser (weighted mean difference -2.46; 95% CI -4.53, -0.38). Nevertheless, low-level laser therapy and pulsed dye laser demonstrated comparable outcomes in surgical scar minimization (weighted mean difference -1.32, 95% CI -3.53, 0.89). The findings of this network meta-analyses suggest that low-level laser therapy and pulsed dye laser are both effective treatments for minimization of scar formation following primary closure of surgical wounds with comparable treatment outcomes.

The impact on quality-of-life following treatment of surgical facial scars with laser-based therapy: a scoping review

Post-surgical scarring impacts quality of life (QOL) and is a significant source of morbidity. Existing treatments targeted at improving the appearance and morbidity of scarring include laser-based therapies. Although lasers are frequently used to improve scar appearance, the effects on QOL are unclear. A scoping review was conducted to assess the impact of laser-based therapy for patients with surgical facial scarring on QOL. Throughout literature review was conducted with the guidance of a medical librarian. Relevant articles underwent two rounds of screening by two, independent reviewers. Data were extracted from each article and later analyzed. Of the four articles analyzed, laser-based therapies were demonstrated as effective in improving QOL for patients with facial scars resultant from surgical intervention. Laser-based therapy should be considered when treating facial scarring resultant from surgical intervention, as it has been shown to improve patient QOL. Standardization of QOL assessment and further studies expanding scar inclusion should be pursued given the paucity of information found through this review.

Advances in Photoelectric Therapy for the Early Intervention and Treatment of Traumatic Scars

Traumatic scar is a disease that affected approximately tens of millions of patients worldwide. According to the histological and morphological properties of scars, the traumatic scar typically includes superficial scar, atrophic scar, hypertrophic scar, and keloid. Its formation is a natural consequence of wound healing, regardless of whether the wound was caused by trauma or surgery. However, the production of scars has considerable impacts on the physical and mental health of patients, even causing substantial aesthetic and functional impairments. Prevention or early treatment of scars is the most suitable therapeutic method, including surgical and non-surgical procedures; nevertheless, the benefits of non-operative therapies for scars are quite limited, and surgical treatments are always hard to achieve satisfying outcomes. Through the application of innovative technologies such as lasers, intense pulsed light, and radiofrequency, significant progress has been made in the treatment of traumatic scars. This review highlights the current advancements of photoelectric therapy for the prevention and treatment of various traumatic scars, which may throw light on innovative therapeutic options for scar therapies.

Excision and adjuvant treatment to prevent keloid recurrence. - a systematic review of prospective, clinical, controlled trials

Keloids are defined as the formation of collagen-rich scar tissue extending beyond the original lesion. Not all keloids respond to conventional treatment with intralesional triamcinolone injections. Recurrence of keloids after primary excision is reported in almost 100% of cases and should therefore always be followed by adjuvant treatment. Currently, consensus on preferred adjuvant treatment in relation to keloid excision is lacking. This study seeks to systematically review evidence on the efficacy of adjuvant treatments in relation to keloid excision. A systematic literature review was conducted on PubMed. Titles, abstracts, and articles were screened and sorted according to defined inclusion- and exclusion criteria. Each study was evaluated according to the Oxford Centre for Evidence-Based Medicine, OCEBM, Levels of Evidence by two independent authors. Seven studies were eligible. Adjuvant treatment methods included intralesional triamcinolone injection, radiotherapy, silicone gel, pressure therapy, verapamil hydrochloride and 5-fluorouracil. While all the included studies reported promising results, two studies showed that minimizing dosages when treating with radiotherapy or triamcinolone should be considered to avoid adverse events. However, a high risk of bias was found in all the included studies.

Synergistic Sequential Emission of Fractional 10.600 and 1540 nm Lasers for Skin Resurfacing: An Ex Vivo Histological Evaluation

Background: Fractional ablative and non-ablative lasers are useful treatments for skin rejuvenation. A procedure that provides the sequential application of fractional ablative followed by non-ablative laser treatment may reduce patients' downtime and deliver better cosmetic results than with either laser alone. Objective: The purpose of the current study was to demonstrate the ameliorative and therapeutic effects in skin remodeling of the synergistic use of the two laser wavelengths (fractional ablative CO₂ and non-ablative 1540 nm) with three different types of pulse shapes, S-Pulse (SP), D-Pulse (DP) and H-Pulse (HP), through which the CO₂ laser can emit, performing an ex vivo histological evaluation. Methods: In this prospective study, ex vivo sheep inner thigh skin was chosen due to its similarity to human skin tissue, and a histological evaluation was performed. Three irradiation conditions, using all of the three CO₂ pulse shapes (alone or averaged), were investigated: (1) 10.600 nm alone, the sequential irradiation of the two wavelengths in the same perfectly controlled energy pulses (DOT) for the entire scan area; ((2) 10.600 nm followed immediately by 1540 nm; and (3) 1540 nm followed immediately by 10.600 nm). Results: When comparing ablative to sequential irradiations, the synergy of the two wavelengths did not alter the typical ablative pulse shape of the 10.600 nm laser alone. With the same CO₂ pulse shape, the lesion depth did not vary with the synergy of the two wavelengths, while thermal lesion width increased compared to CO₂ alone. The ablation rate was achieved, while the total thermal lesion coverage in the scanning area of CO₂ - 1540 lasers was greater than when using CO₂ alone and then the other sequential irradiation. Conclusions: This study provides important preclinical data for new and early uses of the novel 10.600/1540 nm dual-wavelength non-ablative fractional laser. The synergy of the two wavelengths enhanced all the benefits already available when using CO₂ laser systems both in terms of tone strengthening, thanks to a greater shrinking effect, and in terms of stimulation and collagen remodeling thanks to a greater volumetric thermal effect.

Efficacy of Early Application of 1540 nm Non-ablative Fractional Laser and Silicones to Improve Post-epicanthoplasty Scars

The combination of epicanthoplasty and blepharoplasty is a popular choice in Asians to acquire a pair of charming big eyes. However, the obvious scarring in the medial canthal area may result in unsatisfactory aesthetic outcomes. Recently, various laser treatments have been used to deal with scars had achieved detectable improvement, but only a few studies investigating the efficacy of lasers used in post-epicanthoplasty scarring were developed. A total of 70 participants who underwent Z-epicanthoplasty were enrolled in this prospective clinical trial and were randomly assigned to the groups of 1540nm non-ablative fractional laser (NAFL) combined with silicones treatment and silicones alone treatment. The NAFL-exposure in the treated group was additionally applied to the medial canthal area on day 21 postoperatively, compared with the participants in the control group who had only been treated with the daily usage of silicone sheets for 12 hours and silicone gels twice for 5 months after scab had fallen from the skin. Scar evolution was performed by patient and observer scar assessment Scales (POSAS) and visual analogue scale (VAS) for 21 days, and 6 months postoperatively. 64 participants have completed the entire follow-up process. The scar recovery was statistically detected in treated group compared with the control group at 6-month postoperatively assessed by POSAS, especially in pliability of scars. Furthermore, the VAS evaluations showed superior satisfaction in treated group. The early treatment of NAFL combined with silicones has improved scar formation in medial canthal region after epicantholplasties efficiently.Level of Evidence IV This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Laser in surgical scar clearance: An update review

Scar formation is a consequence of wound healing that developed from damaged tissue either from physical injury or surgical incision. A hypertrophic scar develops due to an abnormal healing response to trauma. It might lead to serious functional and cosmetic disability. There are numerous methods mentioned in the literature to treat such scars but to date, no single method has been known to cure them. In this review, we focused on differences between various types of nonsurgical management of hypertrophic scar focusing on the indication, mechanism of action, and efficacy of the pulsed dye laser (PDL), fractional carbon dioxide laser (fCO2), Er-YAG laser, and intense pulse light (IPL). The literature research included peer-reviewed articles (clinical trials or scientific reviews) which were identified by searching electronic databases like PubMed till January 2021 and reference lists of respective articles. Only articles published in the English language were included.

Light emitting diode-red light for reduction of post-surgical scarring: Results from a dose-ranging, split-face, randomized controlled trial

Scarring has significant esthetic and functional consequences for patients. A need exists for anti-scarring therapeutics. Light emitting diode-red light (LED-RL) has been shown to modulate skin fibrosis. The aim of this study is to evaluate the safety and efficacy of LED-RL to reduce post-operative scarring. Cutaneous Understanding of Red-light Efficacy on Scarring was a randomized, mock-controlled, single-blind, dose-ranging, split-face phase II clinical trial. Starting 1 week post-surgery, patients received LED-RL irradiation and temperature-controlled mock therapy to incision sites at fluences of 160, 320 or 480 J/cm2 , triweekly for 3 weeks. Efficacy was assessed at 1, 3 and 6-12 months. The primary endpoint was difference in scar pliability between LED-RL-treated and control sites. Secondary outcomes included Patient and Observer Scar Assessment Scale, collagen and water concentration, and adverse events. There were no significant differences in scar pliability between treated and control scars. At certain fluences, treated scars showed greater improvements in observer rating and scar pliability, reflected by greater reductions in induration, from baseline to 6 months compared to control scars. Treatment-site adverse events included blistering (n = 2) and swelling (n = 1), which were mild and resolved without sequelae. LED-RL phototherapy is safe in the early postoperative period and may reduce scarring.

Early Treatment Effects of Nonablative Fractional Lasers (NAFL) on Hypertrophic Scars in an Animal Model

BACKGROUND AND OBJECTIVES

Recently, there have been several attempts to apply the laser therapy to hypertrophic scars (HTS). In particular, the fractional laser is in the spotlight for its usefulness in rapid wound healing and dermal remodeling. However, most previous studies have focused on the ablative fractional laser (AFL), and there are no studies on the mechanism of the nonablative fractional laser (NAFL) effect in HTS treatment. In this study, we aimed to evaluate the changes in histology and molecular chemistry to provide scientific evidence for the early treatment of HTS with NAFL.

STUDY DESIGN/MATERIALS AND METHODS

A total of 40 hypertrophic burn scars were made on the abdomens of two female pigs. After epithelialization, the HTS were randomly subdivided into four groups-control, AFL, NAFL (low energy), and NAFL (high energy). Laser treatment was initiated 1 week after the crust fell and the epithelium became covered, and it was repeated for six sessions over an interval of 2 weeks. Five excisional biopsies were obtained for histologic analysis and biomarker assessment.

RESULTS

Histologically, dermal remodeling with thin coil-shaped collagen fibers was observed in the NAFL groups. It also showed a significant increase of matrix metalloproteinase-2 (MMP-2) and Decorin at 16 weeks in an enzyme-linked immunosorbent assay. The reverse-transcription polymerase chain reaction analysis showed a tendency that high-pulse energy of NAFL led to higher messenger RNA expression than did the low-energy group.

CONCLUSION

The NAFL-treated groups showed characteristic collagen re-arrangement and a significant increase in MMP-2 and Decorin. These molecular changes suggest that MMP-2 and Decorin play a significant role in dermal remodeling. Early NAFL treatment for HTS could be supported with both histological and molecular evidence. Lasers Surg. Med. © 2020 Wiley Periodicals, Inc.

Stimulation of collagen and elastin production in-vivo using 1,540 nm Er:Glass laser: assessment of safety and efficacy

Introduction: Induction of collagen and elastin remodeling in the human skin can be achieved by non-ablative fractional laser (NAFXL) and ablative fractional laser (AFXL). Our objective was to compare the safety, efficacy, tolerability, and ability to induce collagen and elastin remodeling of NAFXL versus AFXL in a series of treatments over time.Materials and Methods: In this prospective, proof of principle, single-case study, the safety, tolerability and efficacy of the laser systems were assessed via histopathology and clinical evaluations including photographs. Optical biopsies by means of multiphoton tomography (MPT) were used to evaluate the induction of collagen and elastin remodeling.Results: Treatments by both NAFXL and AFXL were well tolerated. The NAFXL system was found to be less painful and resulted in a shorter down- and healing times. MPT findings showed the superior capability of the AFXL procedure to induce collagen; on the other hand, elastin induction was more pronounced after NAFXL treatments.Conclusions: While NAFXL is as effective and safe as the traditional AFXL, it is better tolerated and has a shorter downtime. Serial optical biopsies over time over time can be a useful tool to assess the induction of collagen and elastin remodeling in the human skin.

Laser management of hypertrophic burn scars: a comprehensive review

Hypertrophic scars often develop following burn-related injuries. These scars can be cosmetically unappealing, but associated symptoms of pruritus, pain and restricted range of motion can impair a person’s quality of life. Laser and light therapies offer a minimally invasive, low-risk approach to treatment, with a short postoperative recovery period. As laser technology developed, studies have shown decreased scar thickness, neuropathic pain and need for surgical excision, as well as improved scar pigmentation, erythema, pliability, texture, height and pruritus. In this review, we present the evolution of laser therapy for hypertrophic burn scars, how different types of lasers work, indications, perioperative considerations and guidelines for practice management.

Laser pretreatment for the attenuation of planned surgical scars: A randomized self-controlled hemi-scar pilot study

BACKGROUND

Nonsurgical scar attenuation options include compression garments, silicone gel, intralesional drug therapy, radiation therapy, laser, and light therapies. Laser application preceding surgical intervention has been shown to modify the wound-healing process and affect subsequent scar formation. The objective of this study was to evaluate the safety, efficacy, and final cosmesis of a single presurgical laser treatment on surgical scar formation.

METHODS

This was a randomized, controlled, intraindividual split-scar pilot study with blinded assessments of treated versus untreated planned incision sites. One half of each planned scar was treated by means of an Erbium glass, 1540 nm laser, 24 h before surgery, and the other half was not treated and served as the control. Clinical evaluations and the measurements of patient and physician POSAS scales were done at 1 and 12 months following surgery.

RESULTS

Eleven patients completed the study and were included in the analyses. Laser pretreatment showed a significant beneficial effect compared with no treatment. Both the patient and physician mean Patient and Observer Scar Assessment Scale scores were significantly lower for the laser-treated half of the scars compared with the control side (1.55 to 3.00, p = 0.02 and 2.28 to 4.42, p = 0.03). There was a highly significant interobserver correlation in the evaluation of the overall posttreatment changes (r = 0.904, p < 0.001).

CONCLUSION

A single presurgical laser treatment of a planned incision site is a simple, safe, and painless strategy to significantly improve the final scar appearance.

A dose-ranging, parallel group, split-face, single-blind phase II study of light emitting diode-red light (LED-RL) for skin scarring prevention: study protocol for a randomized controlled trial

BACKGROUND

Skin fibrosis is a significant global health problem that affects over 100 million people annually and has a profoundly negative impact on quality of life. Characterized by excessive fibroblast proliferation and collagen deposition, skin fibrosis underlies a wide spectrum of dermatologic conditions ranging from pathologic scars secondary to injury (e.g., burns, surgery, trauma) to immune-mediated diseases. Effective anti-scarring therapeutics remain an unmet need, underscoring the importance of developing novel approaches to treat and prevent skin fibrosis. Our in vitro data show that light emitting diode-red light (LED-RL) can modulate key cellular and molecular processes involved in skin fibrosis. In two phase I clinical trials (STARS 1 and STARS 2), we demonstrated the safety and tolerability of LED-RL at fluences of 160 J/cm² up to 480 J/cm² on normal human skin.

METHODS/DESIGN

CURES (Cutaneous Understanding of Red-light Efficacy on Scarring) is a dose-ranging, randomized, parallel group, split-face, single-blind, mock-controlled phase II study to evaluate the efficacy of LED-RL to limit post-surgical skin fibrosis in subjects undergoing elective mini-facelift surgery. Thirty subjects will be randomly allocated to three treatment groups to receive LED-RL phototherapy or temperature-matched mock irradiation (control) to either periauricular incision site at fluences of 160 J/cm², 320 J/cm², or 480 J/cm². Starting one week post-surgery (postoperative days 4-8), treatments will be administered three times weekly for three consecutive weeks, followed by efficacy assessments at 30 days, 3 months, and 6 months. The primary endpoint is the difference in scar pliability between LED-RL-treated and control sites as determined by skin elasticity and induration measurements. Secondary outcomes include clinical and photographic evaluations of scars, 3D skin imaging analysis, histological and molecular analyses, and adverse events.

DISCUSSION

LED-RL is a therapeutic modality of increasing importance in dermatology, and has the potential to limit skin fibrosis clinically by decreasing dermal fibroblast activity and collagen production. The administration of LED-RL phototherapy in the early postoperative period may optimize wound healing and prevent excessive scarring. The results from this study may change the current treatment paradigm for fibrotic skin diseases and help to pioneer LED-RL as a safe, non-invasive, cost-effective, portable, at-home therapy for scars.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03795116 . Registered on 20 December 2018.

Advances in the treatment of traumatic scars with laser, intense pulsed light, radiofrequency, and ultrasound

Traumatic scarring is one of the most common complications after soft tissue injury caused by burns and trauma, which affects tens of millions of people worldwide every year. Traumatic scars diminish the quality of life due to disfigurement, symptoms of pain and itch, and restricted motion. The pathogenesis and pathophysiology of traumatic scar remain elusive. The management for traumatic scars is comprised of surgical and non-surgical interventions such as pressure therapy, silicone, corticosteroid, and radiotherapy, which are chosen by clinicians based on the physical examinations of scars. Recently, great progress in treating traumatic scars has been achieved by the development of novel technologies including laser, intense pulsed light (IPL), radiofrequency, and ultrasound. The aim of this review article was to summarize the advances of these technologies for traumatic scars intervention.

Early laser intervention to reduce scar formation - a systematic review

The ability of laser treatment to affect wound healing and subsequently minimize scar formation has been investigated in recent years. However, no systematic review links these clinical trials. The aim of this study was to systematically review and evaluate clinical evidence for early laser intervention to reduce scar formation in studies where laser treatment was introduced less than 3 months after wounding. We searched PubMed using relevant keywords in June 2017. Titles, abstracts and articles were sorted according to inclusion and exclusion criteria. Methodological quality was evaluated according to Cochrane Collaborations risk-of-bias assessment guideline by two independent authors. Twenty-five articles met the inclusion criteria. In total, 22 of 25 studies were controlled studies, and 17 of 25 studies compared laser treatment vs. untreated control scars. The following laser devices have been investigated: pulsed dye laser (PDL), potassium-titanyl-phosphate (KTP) laser, fractional erbium:glass 1540 nm/1550 nm, fractional/full ablation erbium-doped yttrium aluminium garnet (Er:YAG) laser or fractional CO2 laser. Eighteen studies applied laser treatments 2-4 times with 2- to 8-week intervals, while seven studies applied only one laser treatment. Follow-up time ranged from 1 to 12 months with 18 studies using a follow-up time ≤3 months. In general, laser-treated wounds and scars showed benefit from laser intervention, though not always reaching significance. Significant scar improvement was found in three of four studies using laser treatment in inflammation phase, in six of 16 studies with laser initiated in the proliferation phase and in two of five studies in the remodelling phase. High risk of bias was found in randomization and allocation concealment, and low risk of bias with regard to blinding of outcome assessment and lost to follow-up. In conclusion, laser intervention when introduced in inflammation, proliferation or remodelling phase has the potential to reduce cutaneous scar formation. Further, high-quality studies are needed before standard protocols can be implemented in clinical practice.