Medical Policy

Policy Num:      07.001.173
Policy Name:    Fractional Carbon Dioxide (CO2) Laser Ablation Treatment of Hypertrophic Scars or Keloids for Functional Improvement

Policy ID:          [07.001.173]  Ac / B / M- / P-]  [2.01.107]

Last Review:     February 03, 2026
Next Review:     February 15, 2027

Publication Date: March, 2026

Related Policies:

01.002.004 - Negative Pressure Wound Therapy in the Outpatient Setting
02.001.018- Electrostimulation and Electromagnetic Therapy for Treating Wounds
02.001.052 - Noncontact Ultrasound Treatment for Wounds

Fractional Carbon Dioxide (CO2) Laser Ablation Treatment of Hypertrophic Scars or Keloids for Functional Improvement

summary

Description

Hypertrophic scars and keloids are cutaneous lesions resulting from abnormal wound healing. There is no gold standard therapy for hypertrophic scars and keloids, and treatment frequently involves multiple techniques, including pharmacotherapy, compression, surgery, radiation, and light sources. For scars and keloids impairing function, fractional carbon dioxide (CO2) ablative laser treatment is proposed to improve abnormal texture, thickness, and stiffness of scars by ablative destruction and resurfacing. The treatment may be used as monotherapy or in combination with other therapies (e.g., sequential treatment with other lasers, sequential treatment with other therapies, or laser-assisted drug delivery).

Summary of Evidence

For individuals with hypertrophic scars who receive fractional CO2 ablative laser treatment as monotherapy for functional improvement, the evidence includes randomized controlled trials (RCTs), nonrandomized studies, and systematic reviews of these studies. Relevant outcomes are functional improvement, quality of life, and adverse effects of treatment. A Cochrane systematic review included 3 RCTs of CO2 fractional therapy as monotherapy compared to no treatment. None evaluated functional outcomes. For all outcomes reported, the review authors graded the overall evidence as very low certainty, downgraded for very serious imprecision and serious risk of bias. The reviewers concluded that it was unclear whether fractional CO2 laser impacts scar severity compared with no treatment as measured by commonly used scar scales. Conclusions were limited by study heterogeneity and lack of functional outcome measures. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.

For individuals with keloids who receive fractional CO2 ablative laser treatment as monotherapy for functional improvement, the evidence includes RCTs, nonrandomized studies, and systematic reviews of these studies. Relevant outcomes are functional improvement, quality of life, and adverse effects of treatment. One RCT included in a Cochrane review evaluated CO2 fractional laser therapy monotherapy for keloids compared to no treatment. The review authors concluded that it is uncertain whether fractional CO2 impacts on keloid scar severity compared to no treatment after up to 6 months, downgrading the evidence for very serious imprecision and serious risk of bias. Adverse events and function were not assessed. Scar pain and pruritus outcomes were not presented by treatment arm. Another systematic review included 1 RCT of CO2 fractional laser monotherapy compared to intralesional triamcinolone and found no significant differences between keloid response but faster improvement in the intralesional triamcinolone group. Functional outcomes were not evaluated. Conclusions were limited by study heterogeneity and lack of functional outcome measures. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.

For individuals with hypertrophic scars who receive fractional CO2 ablative laser treatment as adjunctive therapy for functional improvement, the evidence includes RCTs, nonrandomized studies, and systematic reviews of these studies. Relevant outcomes are functional improvement, quality of life, and adverse effects of treatment. A systematic review included a 3-arm RCT that compared combination therapy with CO2 laser plus laser, CO2 monotherapy, or no therapy in 23 individuals with hypertrophic scars. Statistically significant improvements were found on commonly used scar scales for both CO2 plus intense pulsed light (IPL) laser and for CO2 alone. The reviewers determined the trial was at unclear risk of bias for unclear adequacy of allocation concealment and blinding. Functional outcomes were not evaluated, and adverse events were not reported. Conclusions were limited by study heterogeneity and lack of functional outcome measures. Another RCT investigated fractional CO2 alone, pulsed dye laser alone, or combined treatment for hypertrophic burn scars and found that all therapies resulted in significant improvements in scar characteristics, but the combined group had the greatest magnitude of effect. A network meta-analysis found that combined fractional CO2 laser therapy plus 5-fluorouracil had the greatest improvements in Vancouver Scar Scale, scar pliability, and thickness, while amongst laser monotherapies, fractional CO2 laser had the greatest improvement in Vancouver Scar Scale. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.

For individuals with keloids who receive fractional CO2 ablative laser treatment as adjunctive therapy for functional improvement, the evidence includes a RCT, nonrandomized studies, and systematic reviews of these studies. Relevant outcomes are functional improvement, quality of life, and adverse effects of treatment. One RCT included in 2 systematic reviews compared CO2 laser plus intralesional triamcinolone to cryosurgery plus triamcinolone. Of 60 individuals enrolled, 23 were lost to follow-up and not assessed. Scar severity ratings favored the laser therapy group at 12 months, but certainty of the evidence was downgraded due to very serious imprecision and serious risk of bias. Pain not related to treatment favored the CO2 group, but there was no difference in pruritus score. There were more frequent early adverse effects in the CO2 laser group. At 12 months, there was a recurrence of 6 keloid scars (16.7%), all of which were in the CO2 laser group. Conclusions were limited by heterogeneity of subject characteristics and study outcomes measures, small sample sizes, and inconsistent study designs. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.

Additional Information

Not applicable.

Objective

The objective of this evidence review is to determine if carbon dioxide fractional laser ablation treatment improves the net health outcome in individuals with hypertrophic scars or keloids impairing function.

Policy Statements

Carbon dioxide (CO2) fractional laser ablation treatment of hypertrophic scars or keloids for functional improvement is considered investigational.

Policy Guidelines

Coding

See the Codes table for details.

Benefit Application

BlueCard/National Account Issues

State or federal mandates (eg, Federal Employee Program) may dictate that certain U.S. Food and Drug Administration approved devices, drugs, or biologics may not be considered investigational, and thus these devices may be assessed only by their medical necessity.

Benefits are determined by the group contract, member benefit booklet, and/or individual subscriber certificate in effect at the time services were rendered. Benefit products or negotiated coverages may have all or some of the services discussed in this medical policy excluded from their coverage.

Background

Hypertrophic Scars and Keloids

Hypertrophic scars and keloids are cutaneous lesions resulting from abnormal wound healing. Hypertrophic scars present as raised lesions that do not exceed the limits of the original skin injury. They tend to regress spontaneously within 1 year.^1, Keloids present as raised, firm lesions that extend beyond the margins of original injury. Keloids do not regress spontaneously, are often refractory to treatment, and have a high probability of recurrence after excision. The highest prevalence of keloids is in people of color, with an incidence of up to 16% in Black Africans.^2, Keloids can occur months or years after injury.^3,

Consensus-based clinical recommendations published in 2014 endorsed the use of a scar classification system first developed in 2002.^4, In this system, hypertrophic scars are classified as linear (e.g., surgical, traumatic) or widespread (e.g., burn). Keloids are classified as minor or major. Minor keloids are focally raised, itchy scars extending over normal tissue. Major keloids are large, raised (>0.5 cm) scars, possibly painful or pruritic, and extending over normal tissue. Major keloids are often refractory to treatment and have a high probability of recurrence after excision. Mature scars are light-colored and flat. Immature scars are slightly elevated in the process of remodeling and may be painful or itchy. Immature hypertrophic scars (red, slightly raised) may develop into hypertrophic scars; if they persist for longer than 1 month, the guidelines recommend treating them as a linear hypertrophic scar.

There is no gold standard therapy for hypertrophic scars and keloids, and treatment frequently involves multiple techniques, including pharmacotherapy, compression, surgery, radiation, and light sources.^5,

Laser Therapy for Scar Treatment

Carbon dioxide (CO2) fractional laser treatment was initially developed for cosmetic purposes (e.g., photoaging, acne scarring). Fractional CO2 laser ablation works by creating microscopic thermal wounds, resulting in tissue vaporization and coagulation of surrounding extracellular proteins The technique has the advantage of reaching the dermis by ablating the epidermis, while avoiding complications associated with nonfractional ablative lasers (no longer in use), such as postoperative pain and infection. For scars and keloids impairing function, CO2 fractional ablative laser treatment is proposed to improve abnormal texture, thickness, and stiffness of scars by ablative destruction and resurfacing. The treatment may be used as monotherapy or in combination with other therapies (e.g., sequential treatment with other lasers, sequential treatment with other therapies, or laser-assisted drug delivery).

This review focuses on CO2 fractional ablative laser treatment for functional improvement. Other types of lasers used for hypertrophic scars and keloids include pulsed dye laser and intense pulse light.

Regulatory Status

Multiple fractional CO2 laser systems have been approved by FDA through the 510(k) program. These devices have broad indications for dermatological procedures requiring ablation, resurfacing, and coagulation of soft tissue.

FDA Product Codes GEX, ONG.

Rationale

This evidence review was created in January 2024 with a search of the PubMed database. The most recent literature update was performed through November 20, 2025.

Evidence reviews assess the clinical evidence to determine whether the use of a technology improves the net health outcome. Broadly defined, health outcomes are length of life, quality of life, and ability to function including benefits and harms. Every clinical condition has specific outcomes that are important to patients and to managing the course of that condition. Validated outcome measures are necessary to ascertain whether a condition improves or worsens; and whether the magnitude of that change is clinically significant. The net health outcome is a balance of benefits and harms.

To assess whether the evidence is sufficient to draw conclusions about the net health outcome of a technology, 2 domains are examined: the relevance and the quality and credibility. To be relevant, studies must represent one or more intended clinical use of the technology in the intended population and compare an effective and appropriate alternative at a comparable intensity. For some conditions, the alternative will be supportive care or surveillance. The quality and credibility of the evidence depend on study design and conduct, minimizing bias and confounding that can generate incorrect findings. The randomized controlled trial is preferred to assess efficacy; however, in some circumstances, nonrandomized studies may be adequate. Randomized controlled trials are rarely large enough or long enough to capture less common adverse events and long-term effects. Other types of studies can be used for these purposes and to assess generalizability to broader clinical populations and settings of clinical practice.

Population reference No. 1 - 4

Fractional Carbon Dioxide Laser Ablation for Hypertrophic Scars or Keloids

Clinical Context and Therapy Purpose

The purpose of fractional carbon dioxide (CO2) laser ablation in individuals who have who have hypertrophic scars or keloids impairing function is to improve function.

The following PICO was used to select literature to inform this review.

Populations

The relevant populations of interest are individuals with hypertrophic scars or keloids impairing function (e.g., range of motion, strength, activities of daily living).

Interventions

The therapy being considered is fractional CO2 laser ablation.

Fractional CO2 ablative laser treatment may be used as monotherapy or in combination with other therapies (e.g., sequential treatment with other lasers, sequential treatment with other therapies, or laser-assisted drug delivery).

Comparators

Standard care for linear hypertrophic scars includes silicone-based gel or sheeting. Adjunctive use of intralesional corticosteroid injection or 5-fluorouracil is indicated if a 2-month course of silicone gel or sheeting is not effective or if the scar is severe. Surgical intervention to relieve tension is an option when scarring creates functional impairment. For severe scars, surgical excision may be accompanied by layering of triamcinolone, long-term placement of intradermal sutures, and subsequent monthly corticosteroid administration.

First-line treatment for hypertrophic burn scars is silicone gel preparations. Pressure garments and onion extract–containing formulations may also
be used. The complexity of managing burn scars will often require personalized management consisting of combination or alternative therapies
including: silicone gel sheeting; individualized pressure therapy; massage, physical therapy, or both; corticosteroid application; and surgical procedures.

Standard care for keloid scars includes silicone-based dressings and compression dressings.^2,

For established keloids, intralesional corticosteroids are the first-line treatment.^2,

If improvement with conservative therapy is not observed within 8 to 12 weeks, 5-FU in combination with intralesional corticosteroids and, ultimately, laser
therapy or surgical excision may be considered.

Consensus guidelines recommend monthly intralesional corticosteroid administration with or without adjuvant cryotherapy as a first-line option for major keloids. If this strategy is not effective within 3 to 4 months, transition to therapy with monthly intralesional 5-FU and triamcinolone is recommended. Secondary management options for refractory keloids include surgical excision with appropriate prophylactic therapy.

Consensus guidelines note that strategies for managing pathologic scarring are largely determined by scar classification. History of scarring, including past treatment failures or successes, as well as the likelihood of compliance with a chosen therapeutic regimen also influence treatment selection.

Outcomes

Functional outcomes (range of motion, strength, activities of daily living) are the primary outcomes of interest for this review. Additional outcomes of interest are symptoms (pain, itch), quality of life, and adverse effects of treatment.

Frequently-used instruments used for scar assessment in research studies and clinical practice include the Vancouver Scar Scale and the Patient‐Observer Scar Assessment Scale (POSAS).^6, Their usefulness is limited however, because they are not intended to measure functional outcomes. The VSS score is based on 4 parameters (vascularization, height/thickness, pliability, and pigmentation). The POSAS includes an assessment of functional compromise, but is scored as an aggregate of disfigurement, functional compromise, pain, and itch. No minimally clinically important difference has been identified for these scales, and no single scale has been established as the gold standard.[Buhalog]

Study Selection Criteria

Methodologically credible studies were selected using the following principles:

• Good methodological quality systematic reviews (i.e., more than 1 database searched, search strategy and inclusion criteria specified, quality assessment of individual studies, and assessment of the overall body of evidence).

• To assess efficacy outcomes, comparative controlled prospective trials were sought, with a preference for RCTs.

• In the absence of such trials, comparative observational studies were sought, with a preference for prospective studies.

• To assess long-term outcomes and adverse events, single-arm studies that capture longer periods of follow-up and/or larger populations were sought.

• Consistent with a 'best available evidence approach,' within each category of study design, studies with larger sample sizes and longer durations were sought.

• Studies with duplicative or overlapping populations were excluded.

Review of Evidence

Overview of Systematic Reviews

Three recent, good methodological quality systematic reviews have evaluated laser treatment for hypertrophic scars and keloids.^7,1,2,The individual studies included in these systematic reviews are listed in Table 1. The reviews differed in their inclusion criteria and focus (see Table 2), resulting in differences in the bodies of evidence evaluated. Across the reviews, a total of 6 RCTs that evaluated CO2 fractional laser ablation were identified,1 of which was published only in abstract form.

Buhalog et al (2021) conducted a systematic review of laser therapies for hypertrophic burn and traumatic scars.^7, Of 23 studies included, 3 RCTs and 3 nonrandomized studies evaluated CO2 fractional laser ablation. Overall, the reviewers found improvements in nearly all outcome measures across all types of laser therapy. However, conclusions were limited by heterogeneity of the studies and a lack of outcomes measuring function. The study authors recommended that future research include standardized protocols including assessments of function and quality of life.

Peng et al (2021) performed a systematic review of studies investigating the efficacy and safety of fractional CO2 laser therapy, with or without other treatments, for burn scars.^8, A total of 20 studies were identified, including 2 RCTs, 10 observational cohorts, and 8 inpatient controlled studies. The included studies enrolled patients with various types of burn scars, though the authors note that the population consisted predominantly of individuals with hypertrophic burn scars. Pooled analysis demonstrated significant improvement in VSS, POSAS-patient, and POSAS-observer scores with CO2 laser therapy. Improvements were also noted in scar thickness, pigmentation, pliability, height, vascularity, and relief. Limitations of the analysis include substantial heterogeneity across studies, small sample sizes, and the fact that not all included studies specifically investigated patients with hypertrophic burn scars. The authors conclude that fractional CO2 laser therapy significantly improves objective and subjective burn scar outcomes, but larger, well-designed RCTs are needed.

A Cochrane review conducted by Leszczynski et al (2022) evaluated various laser treatments for hypertrophic scars and keloids.^1, The reviewers included a total of 15 RCTs. Of these, 3 evaluated CO2 fractional laser ablation. Overall, the authors concluded that there is insufficient evidence to support or refute the effectiveness of laser therapy for treating hypertrophic and keloid scars. The available information was also insufficient to perform a more accurate analysis on treatment-related adverse effects related to laser therapy. Specific to CO2 laser treatment, they concluded that it is unclear whether fractional CO2 laser impacts on hypertrophic and keloid scar severity compared with no treatment (very low-certainty evidence). There was not enough data to compare fractional CO2 laser versus other interventions. Limitations of the overall body of evidence included heterogeneity of the studies, conflicting results, study design issues and small sample sizes. The authors noted that further high-quality trials are needed.

Walsh et al (2023) conducted a systematic review of keloid treatments published between 2010 and 2020.^2, Of 108 studies included, 5 (2 RCTs) evaluated CO2 laser ablation. In the RCTs, fractional CO2 showed no difference in improvement compared to intralesional verapamil or triamcinolone, and efficacy of CO2 laser with intralesional triamcinolone compared to cryotherapy with intralesional triamcinolone was not significantly different. In 2 nonrandomized studies, recurrence rates were 10.5% at 24 months and 11.7% at 6 months. The reviewers concluded that for all interventions, conclusions were limited by heterogeneity of subject characteristics and study outcomes measures, small sample sizes, and inconsistent study designs.

Foppiani et al. (2024) conducted a network meta-analysis of laser treatments for hypertrophic and keloid scars, analyzing 18 studies (16 RCTs) with a total of 550 participants.^8, The study found that fractional CO2 laser combined with 5-fluorouracil (5-FU) was superior to control in reducing Vancouver Scar Scale scores (Mean difference [MD], -5.97; 95% CI, -7.30 to -4.65), pliability (MD, -2.68; 95% CI, -4.03 to 1.33), and thickness (MD, -2.22; 95% CI, -3.13 to -1.31). However, this combination showed no significant difference compared to control in terms of erythema, vascularity, redness and perfusion (MD, -0.71; 95% CI, -2.72 to 1.30), or pigmentation (MD, -0.44; 95% CI, -1.26 to 0.38). Amongst the laser monotherapies in the analysis, fractional CO2 showed a greater improvement relative to control than PDL, Nd:YAG, and Er: YAG. The authors noted limitations due to heterogeneity across studies in outcomes and follow-up durations, lack of standardized definitions between keloid and hypertrophic scars, and variability in laser parameters and treatment protocols.

Table 1. Studies of Fractional CO2 Ablative Laser Treatment Included in Systematic Reviews of Laser Treatment for Hypertrophic Scars or Keloids

       CO2: carbon dioxide; LADD: laser-assisted drug delivery; N: sample size; RCT: randomized controlled trial.  

Table 2. Systematic Reviews of Fractional CO2 Ablative Laser Treatment for Hypertrophic Scars and Keloids

        CO2: carbon dioxide; RCT: randomized controlled trial.

Randomized Controlled Trials

The following sections provide more detail on the RCTs included in the systematic reviews discussed above. The full-text of these RCTs were reviewed to determine if they provided information on functional outcomes, but no additional data was identified.

Monotherapy for Hypertrophic Scars

Three RCTS included in the Cochrane review evaluated CO2 fractional therapy as monotherapy versus no treatment. ^11,13,16,   For all outcomes reported, the review authors graded the overall evidence as very low certainty, downgraded for very serious imprecision and serious risk of bias. None of the studies evaluated functional outcomes.

Monotherapy for Keloids

One RCT included in the Cochrane review evaluated CO2 fractional laser therapy monotherapy for keloids.^11, The review authors concluded that it is uncertain whether fractional CO2 impacts on keloid scar severity compared to no treatment after up to 6 months, downgrading the evidence for very serious imprecision and serious risk of bias. Adverse events were not assessed. Scar pain and pruritus outcomes were not presented by treatment arm.

Walsh et al included 1 RCT of CO2 fractional laser monotherapy versus intralesional triamcinolone and found no significant differences between keloid response but faster improvement in the intralesional triamcinolone group.^40,

Neither study evaluated functional outcomes.

Combination Therapy for Hypertrophic Scars

Buhalog et al included a 3-arm RCT that compared combination therapy with CO2 laser plus intense pulsed light (IPL), CO2 monotherapy, or no therapy in 23 individuals with hypertrophic scars.^16, Statistically significant improvements were found on the Manchester Scar Scale and the POSAS for both CO2 plus IPL and for CO2 alone. The reviewers determined the trial was at unclear risk of bias for unclear adequacy of allocation concealment and blinding. Functional outcomes were not evaluated and adverse events were not reported.

Kivi et al. (2024) conducted a randomized single-blinded clinical trial to compare the efficacy and safety of CO2 fractional laser combined with pulsed dye laser (PDL) versus either treatment alone for hypertrophic burn scars.^45, Among 60 scars in 20 patients, all treatments significantly improved VSS scores, but the combination therapy showed the greatest improvement. While all interventions significantly improved scar color and pliability, only combination therapy significantly reduced scar height, with the most pronounced effects across all outcomes observed in this group. The study’s limitations included a small sample size without power calculations, lack of functional and adverse event reporting, and a single-center design.

Combination Therapy for Keloids

One RCT included in both the Cochrane review and in Walsh et al compared CO2 laser plus intralesional triamcinolone to cryosurgery plus triamcinolone.^12, Of 60 individuals enrolled, 23 were lost to follow-up and not assessed. Scar severity ratings favored the laser therapy group at 12 months, but the certainty of the evidence was downgraded due to very serious imprecision and serious risk of bias. Pain not related to treatment favored the CO2 group, but there was no difference in pruritus score. There were more frequent early adverse effects in the CO2 laser group. At 12 months, there was a recurrence of 6 keloid scars (16.7%), all of which were in the CO2 laser group.

Combination Therapy for Keloids

One RCT included in both the Cochrane review and in Walsh et al compared CO2 laser plus intralesional triamcinolone to cryosurgery plus triamcinolone. ^12,  Of 60 individuals enrolled, 23 were lost to follow-up and not assessed. Scar severity ratings favored the laser therapy group at 12 months, but certainty of the evidence was downgraded due to very serious imprecision and serious risk of bias. Pain not related to treatment favored the CO2 group, but there was no difference in pruritus score. There were more frequent early adverse effects in the CO2 laser group. At 12 months, there was a recurrence of 6 keloid scars (16.7%), all of which were in the CO2 laser group.

Population reference No. 1 

For individuals with hypertrophic scars who receive fractional CO2 ablative laser treatment as monotherapy for functional improvement, the evidence includes randomized controlled trials (RCTs), nonrandomized studies, and systematic reviews of these studies. Relevant outcomes are functional improvement, quality of life, and adverse effects of treatment. A Cochrane systematic review included 3 RCTs of CO2 fractional therapy as monotherapy compared to no treatment. None evaluated functional outcomes. For all outcomes reported, the review authors graded the overall evidence as very low certainty, downgraded for very serious imprecision and serious risk of bias. The reviewers concluded that it was unclear whether fractional CO2 laser impacts scar severity compared with no treatment as measured by commonly used scar scales. Conclusions were limited by study heterogeneity and lack of functional outcome measures. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.

Population reference No. 2

For individuals with keloids who receive fractional CO2 ablative laser treatment as monotherapy for functional improvement, the evidence includes RCTs, nonrandomized studies, and systematic reviews of these studies. Relevant outcomes are functional improvement, quality of life, and adverse effects of treatment. One RCT included in a Cochrane review evaluated CO2 fractional laser therapy monotherapy for keloids compared to no treatment. The review authors concluded that it is uncertain whether fractional CO2 impacts on keloid scar severity compared to no treatment after up to 6 months, downgrading the evidence for very serious imprecision and serious risk of bias. Adverse events and function were not assessed. Scar pain and pruritus outcomes were not presented by treatment arm. Another systematic review included 1 RCT of CO2 fractional laser monotherapy compared to intralesional triamcinolone and found no significant differences between keloid response but faster improvement in the intralesional triamcinolone group. Functional outcomes were not evaluated. Conclusions were limited by study heterogeneity and lack of functional outcome measures. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.

Population reference No. 3

For individuals with hypertrophic scars who receive fractional CO2 ablative laser treatment as adjunctive therapy for functional improvement, the evidence includes RCTs, nonrandomized studies, and systematic reviews of these studies. Relevant outcomes are functional improvement, quality of life, and adverse effects of treatment. A systematic review included a 3-arm RCT that compared combination therapy with CO2 laser plus laser, CO2 monotherapy, or no therapy in 23 individuals with hypertrophic scars. Statistically significant improvements were found on commonly used scar scales for both CO2 plus intense pulsed light (IPL) laser and for CO2 alone. The reviewers determined the trial was at unclear risk of bias for unclear adequacy of allocation concealment and blinding. Functional outcomes were not evaluated, and adverse events were not reported. Conclusions were limited by study heterogeneity and lack of functional outcome measures. Another RCT investigated fractional CO2 alone, pulsed dye laser alone, or combined treatment for hypertrophic burn scars and found that all therapies resulted in significant improvements in scar characteristics, but the combined group had the greatest magnitude of effect. A network meta-analysis found that combined fractional CO2 laser therapy plus 5-fluorouracil had the greatest improvements in Vancouver Scar Scale, scar pliability, and thickness, while amongst laser monotherapies, fractional CO2 laser had the greatest improvement in Vancouver Scar Scale. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.

Population reference No. 4

For individuals with keloids who receive fractional CO2 ablative laser treatment as adjunctive therapy for functional improvement, the evidence includes a RCT, nonrandomized studies, and systematic reviews of these studies. Relevant outcomes are functional improvement, quality of life, and adverse effects of treatment. One RCT included in 2 systematic reviews compared CO2 laser plus intralesional triamcinolone to cryosurgery plus triamcinolone. Of 60 individuals enrolled, 23 were lost to follow-up and not assessed. Scar severity ratings favored the laser therapy group at 12 months, but certainty of the evidence was downgraded due to very serious imprecision and serious risk of bias. Pain not related to treatment favored the CO2 group, but there was no difference in pruritus score. There were more frequent early adverse effects in the CO2 laser group. At 12 months, there was a recurrence of 6 keloid scars (16.7%), all of which were in the CO2 laser group. Conclusions were limited by heterogeneity of subject characteristics and study outcomes measures, small sample sizes, and inconsistent study designs. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.

Supplemental Information

The purpose of the following information is to provide reference material. Inclusion does not imply endorsement or alignment with the evidence review conclusions.

Practice Guidelines and Position Statements

Guidelines or position statements will be considered for inclusion in 'Supplemental Information' if they were issued by, or jointly by, a US professional society, an international society with US representation, or National Institute for Health and Care Excellence (NICE). Priority will be given to guidelines that are informed by a systematic review, include strength of evidence ratings, and include a description of management of conflict of interest.

International Advisory Panel on Scar Management

In 2014, Gold et al published updated international clinical recommendations on scar management.^4, Although they were not informed by a systematic review and strength of evidence ratings were not provided, the recommendations are frequently cited and were accompanied by a narrative review of the literature.^5, The recommendation document notes that, where clinical evidence was lacking, management recommendations were based on advisory panel member consensus.

Specific recommendations on laser therapy include the following, according to scar classification:

Immature or Erythmatous Hypertrophic Scars

• "In the case of persistent erythema for more than a month despite preventative efforts, management should transition to that of a linear hypertrophic scar or alternatively, pulsed-dye laser therapy may be applied once monthly for 2 to 3 months. If the scar is unresponsive to the pulsed-dye laser, fractional laser therapy or treatment as a linear hypertrophic scar may be instituted."

Linear Hypertrophic Scars Arising from Surgery or Trauma

• "Pulsed-dye or fractional laser therapy are second-line and, often, first -line options for linear hypertrophic scars."

Widespread Burn Hypertrophic Scars

• "Positive data for fractional lasers support their use for burn scar treatment. Ablative fractional lasers offer the advantage of fewer treatment sessions compared with nonablative options."

Minor Keloids

• "If improvement with conservative therapy is not observed within 8 to 12 weeks, 5-FU in combination with intralesional corticosteroids and, ultimately, laser therapy or surgical excision may be considered. Although data from published clinical trials are lacking, some advisory panel members suggest the use of ablative fractional lasers over other types of laser therapy for the treatment of refractory keloids."

Major Keloids

• "Secondary management options for refractory keloids include laser treatment and surgical excision with appropriate prophylactic therapy."

Consensus Recommendations

In 2020, Seago et al published consensus recommendations on laser treatment of scars and contractures.^6, The recommendations were developed by a panel of 26 dermatologists and plastic and reconstructive surgeons from 13 countries between March 2018 and March 2019. The panel used a modified Delphi method consisting of 2 rounds of email questionnaires and supplementary face-to-face meetings. The threshold for consensus recommendations was at least 80% concurrence among the panel members. The recommendations were not informed by a systematic review and do not include strength of evidence ratings.

Specific recommendation statements on laser therapy include the following:

• "The panel members are unanimous in their view that lasers are a first‐line therapy in the management of traumatic scars and contractures."

• "The potential indications for laser treatment are determined based on clinical findings (i.e., erythema, hypopigmentation, hyperpigmentation, atrophy, hypertrophy, degree of epithelialization, pliability, and restriction) as well as subjective symptoms including pain and pruritus."

• "The fractional lasers, especially AFL, have the most potential to treat the entire range of clinical issues as a single modality. The optimal treatment routinely includes multiple laser types in concurrent or alternating treatment sessions to suit varying clinical presentations and treatment goals in a particular location at a particular time. Effective comprehensive traumatic scar management frequently incorporates surgical evaluation, ongoing conservative measures (i.e., compression, massage, and silicone gels and sheets); physical and occupational therapy; medical management such as corticosteroids and antimetabolites; and mental health evaluation where appropriate."

The document also includes recommendations on device application and settings but notes, "Optimal wavelengths and settings for traumatic scar
management have not yet been fully elaborated in the literature and settings will vary depending on the characteristics of the particular device chosen by the operator, the clinical findings on the day of the visit (e.g., degree of erythema, presence of a tan, etc.), and issues specific to the patient (e.g., pain tolerance, approximate downtime, etc.)."

In its recommendations on scar assessment, the panel noted, "Continuing research is vital to determining the optimal laser devices, timing, combinations, and settings in the management of traumatic scars," and "Given the greater range of scar response to current laser techniques such as AFL, future scar assessment should incorporate evaluation of function, symptom relief, and overall quality of life to a greater extent."

A 2014 Consensus report from 8 experts with extensive experience in the use of lasers for scar treatment notes that AFLs are considered more effective than nonablative fractional lasers (NAFLs) for hypertrophic scars due to their ability to induce more robust remodeling.^46, Among AFLs, CO2 lasers are favored over erbium:YAG, because CO2 provides greater surrounding tissue coagulation and reduces bleeding risk.

U.S. Preventive Services Task Force Recommendations

Not applicable.

Medicare National Coverage

There is no national coverage determination. In the absence of a national coverage determination, coverage decisions are left to the discretion of local Medicare carriers.

Ongoing and Unpublished Clinical Trials

Some currently unpublished trials that might influence this review are listed in Table 3.

Table 3. Summary of Key Trials

 NCT: national clinical trial.

References

1. Leszczynski R, da Silva CA, Pinto ACPN, et al. Laser therapy for treating hypertrophic and keloid scars. Cochrane Database Syst Rev. Sep 26 2022; 9(9): CD011642. PMID 36161591
2. Walsh LA, Wu E, Pontes D, et al. Keloid treatments: an evidence-based systematic review of recent advances. Syst Rev. Mar 14 2023; 12(1): 42. PMID 36918908
3. UpToDate. Laser Therapy for Hypertrophic Scars and Keloids. Updated: Dec 04, 2023. https://www.uptodate.com/contents/laser-therapy-for-hypertrophic-scars-and-keloids. Accessed November 20, 2025.
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