Laser Revision of Scars

Anatomy and Physiology

Scar formation results from dermal injury, triggering a complex wound healing cascade influenced by multiple factors, including genetic predisposition, wound depth, location, tension, infection, inflammation, and hormonal influences.[6][7] Hypertrophic scars and keloids arise from dysregulated fibroblast proliferation and excessive collagen deposition, often with a familial predisposition.[8] They most commonly affect individuals aged 10 to 30, with no sex predilection.[7] Keloids are more prevalent in African-American, Hispanic, and Asian populations, with an incidence of 4% to 16%.[9] Hypertrophic scars result from excessive collagen synthesis with inadequate lysis during the remodeling phase, forming thick, hyalinized collagen bundles composed of fibroblasts and fibrocytes.[8] Keloid formation is driven by increased transforming growth factor-beta (TGF-β) production, which prolongs the proliferative phase of wound healing and enhances fibroblast-mediated collagen synthesis.[10] Emerging research implicates mechanical forces and hypoxia in keloid pathogenesis, activating profibrotic signaling via pathways such as Wnt/β-catenin and PI3K/Akt.[11]

Conversely, atrophic scars are characterized by dermal depressions resulting from collagen degradation induced by cutaneous inflammation.[12] These scars commonly develop in inflammatory conditions such as acne vulgaris, varicella, lupus, and following surgery or trauma. Acne vulgaris affects up to 80% of individuals aged 11 to 30 and is the most common cause of atrophic scarring.[2] Atrophic scars occur 3 times more frequently than keloids or hypertrophic scars.[13] Their formation results from an imbalance between collagen matrix synthesis and its degradation by proteases, with recent evidence implicating matrix metalloproteinases (MMPs) and cytokine dysregulation in their pathogenesis.[14]

Hypertrophic scars present as firm, raised, red, or pink lesions that remain confined to the borders of the original injury. They typically develop within a month of injury and may spontaneously regress.[2] In contrast, keloids appear as firm, pink to purple nodular scars that extend beyond the original wound margins. They may arise weeks to years postinjury and do not regress spontaneously.[2] Keloids are more prevalent in individuals with darker Fitzpatrick skin types, and their response to laser therapy varies depending on lesion maturity and vascularity.

Atrophic scars, characterized by dermal depressions due to collagen loss exceeding synthesis, are commonly associated with acne but may also result from infections, trauma, or surgery.[2] They are subclassified into 3 types: ice pick, boxcar, and rolling scars. Ice pick scars are narrow, deep, sharply marginated tracts that extend vertically to the deep dermis or subcutaneous tissue.[2] Boxcar scars are round to oval depressions broader than ice pick scars, with sharply demarcated vertical edges. Rolling scars are the widest and display an undulating skin appearance due to fibrous tethering of the dermis to the subcutis.[13]

Indications

Indications for laser scar revision include atrophic, hypertrophic, and keloid scars in patients who seek to improve the cosmetic appearance and the functional symptoms of their scars, such as pruritus, pain, and restricted movement. Laser therapy is often indicated when scars are symptomatic, disfiguring, or psychologically distressing.

Recent evidence supports early laser intervention, particularly fractional ablative and nonablative devices, in managing immature scars to prevent worsening and improve remodeling. Laser modalities are selected based on scar type, color, depth, and patient skin type, with outcomes optimized through individualized treatment plans.[15]

Contraindications

Contraindications to laser therapy include recent oral retinoid use within the past year, pregnancy, breastfeeding, immunosuppression, connective tissue disorders, and the presence of concomitant skin disease at the treatment site. A thorough patient history is essential to identify these contraindications and minimize potential complications. Additionally, patients with a history of herpes simplex virus (HSV) should receive prophylactic antiviral therapy before laser treatment to prevent reactivation. Proper patient selection and pretreatment precautions are critical to ensuring the safety and efficacy of laser therapy while reducing the risk of adverse effects.

Equipment

Equipment required for the laser revision of scars include:

• Laser machine
• Digital camera
• Tray with a local anesthetic, postlaser emollient cream, antiirritation gel, and measurement tape

Personnel

Personnel required for the laser revision of scars include:

• Dermatologist
• Aesthetic medicine specialist
• Plastic surgeon
• Dermatology nurse
• Laser technician/technologist
• Aesthetic technologist

Preparation

A thorough evaluation of scars involves both clinical assessment and patient history to determine the most appropriate treatment approach. Scars should be classified as hypertrophic, keloidal, atrophic, or normotrophic, considering their age, prior treatments, and the underlying cause, such as trauma, surgery, or an inflammatory condition. Assessing the patient’s Fitzpatrick skin phototype is crucial as it influences the risk of pigmentary alterations, postinflammatory hyperpigmentation (PIH), and overall scarring outcomes. Objective tools like reflectance spectrophotometry can aid in more precise skin type classification, ensuring a tailored and effective treatment plan.[16]

Pretreatment photographs and measurements should be obtained and regularly updated to track treatment progress. Each clinical visit should include pigmentation, pliability, and scar height documentation. Prior to laser therapy, the scar should be treated with a topical anesthetic for 30 to 60 minutes, and the area should be cleansed with an antiseptic solution. Patients with a history of herpes simplex virus (HSV) affecting the treatment site should receive prophylactic antiviral therapy to prevent postlaser reactivation.[17] Additionally, in individuals with Fitzpatrick skin types IV to VI, pretreatment with depigmenting agents such as hydroquinone may help minimize the risk of PIH, improving treatment safety and efficacy.[18]

Technique or Treatment

Laser scar revision utilizes photothermal energy to target intra and extracellular structures within scar tissue to stimulate the eventual remodeling of dermal collagen and elastin. Various types of lasers have been used to treat scars since the 1980s, beginning with continuous-wave argon, CO₂, and Nd:YAG 1064 lasers, followed by the application of pulsed dye laser (PDL) and Er:YAG lasers for scar revision.[19] Most recently, fractional photothermolysis with ablative and nonablative fractionated lasers has been an effective treatment for scars.[2]

For hypertrophic scars and keloids, the PDL is the most common nonablative laser (PDL: 585 to 595 nm).[2] PDL effectively improves hypertrophic scars and keloids' vascularity, pliability, color, and height.[20] Previous studies have reported a 57% to 83% improvement in hypertrophic scars' clinical appearance and texture after 1 to 2 PDL treatments.[21]. The most commonly used nonablative lasers for atrophic facial scars are Nd:YAG and 1450-nm diode lasers. One study reported an improvement of 40% to 45% with 1320-nm Nd:YAG or 1450-nm diode laser treatment after an average of 3 consecutive monthly treatment sessions, as assessed by patient satisfaction surveys, histologic evaluations, and skin texture measurements.[2] Nonablative lasers have minimal downtime and produce gradual results, with the most significant improvement noted between 3 and 6 months following the final laser treatment.[2]

Nonablative fractional lasers have significantly improved the pigmentation and thickness of surgical, atrophic, hypertrophic, and hypopigmented scars.[22] A study by Tierney et al comparing 1550-nm nonablative fractional lasers to 595-nm PDL for the treatment of surgical scars showed that nonablative fractional lasers outperformed PDL, and 83% of patients preferred the half of the scar treated with a nonablative fractional laser.[22][23] Niwa et al examined nonablative fractional lasers in treating hypertrophic scars and found 26% to 75% clinical improvement after 2 to 3 treatment sessions at 4-week intervals.[19]

Ablative laser resurfacing, with CO₂ or Er:YAG lasers, is effective for traumatic and surgical scars, especially when resurfaced within 6 to 10 weeks after trauma or surgery or even immediately after surgery.[24] CO₂ and Er:YAG lasers are also effective for atrophic scars due to their ability to smooth scar texture and stimulate collagen production within facial atrophic scars, although patients must consider the potential for significant downtime as reepithelialization typically takes 4 to 7 days with Er:YAG and 7 to 10 days with the CO₂ laser.[25] While requiring more downtime, ablative lasers usually produce more clinical improvement.

Previous head-to-head studies have suggested that CO₂ laser produces superior results for acne scars, while Er:YAG is better tolerated with less downtime.[26] Raised and shallow boxcar scars improve the most with laser resurfacing, while icepick scars are more challenging to treat and may necessitate secondary resurfacing.[24] Nonablative lasers are also useful for acne scars.

More recently, fractional ablative laser resurfacing has emerged as a popular treatment modality for atrophic and surgical scars. In fractional ablative resurfacing, columns of thermal damage, called microscopic thermal treatment zones, are separated by surrounding untreated skin. This results in rapid reepithelialization and reduced downtime as only a fraction of the skin is altered.[27] The microthermal treatment zones also allow fractional lasers to penetrate the skin more deeply than fully ablative lasers.[28] A double-blinded split-scar study by Tidwell et al reported a significantly superior outcome with fractionated Er:YAG compared to fully ablative Er:YAG for surgical scar revision, with 94% of patients preferring the side of the scar treated with fractional ablative resurfacing.[28] Another study showed fractional CO₂ laser to be effective in treating atrophic traumatic scars in 70% of patients treated with 6 monthly sessions of fractional CO₂ laser treatment.[27]

Complications

The adverse effects of nonablative laser options are generally mild and include transient erythema, which resolves within 24 hours. Blistering, crusting, scarring, and postinflammatory hyperpigmentation are rare and occur most commonly in darker skin types.[2] The most frequently encountered side effect of PDL treatment is posttreatment purpura, lasting for up to 1 week.[29]

Nonablative fractional resurfacing laser adverse effects include mild to moderate pain during treatment and erythema and edema posttreatment lasting up to 2 to 4 days.[24]

Side effects of ablative laser resurfacing include temporary burning discomfort, oozing, crusting, ulceration, erythema, edema, acneiform eruptions, eczematous dermatitis, and infections.[24] Long-term adverse effects include dyspigmentation and scarring.[27] Erythema and edema typically worsen within the first 24 to 48 hours after treatment, with erythema occasionally lasting up to 4 months posttreatment. One study reported an average duration of posttreatment erythema for 1 month.[30] Transient postinflammatory hyperpigmentation occurs 2 to 4 weeks after treatment and is more common in darker skin phototypes. In a study of Fitzpatrick skin types III to V, 45.5% developed transient hyperpigmentation that resolved within 3 months in 90% of affected patients.[30]

Fractional ablative laser resurfacing adverse effects are generally transient and less severe than fully ablative resurfacing.[29][27] Erythema, crusting, burning sensation, edema, and bruising were reported after fractional CO₂ laser treatment.[27] Persistent erythema and postinflammatory pigmentary changes are less common complications when compared to fully ablative skin resurfacing.[27]

Clinical Significance

Laser therapy is an effective and safe treatment modality for multiple types of scars. Several studies have demonstrated high patient satisfaction rates with the cosmetic outcome of various laser treatments. The emergence of fractional ablative laser devices has led to superior outcomes with decreased downtime compared to traditional fully ablative lasers, thereby increasing the appeal of laser treatment for patients. In addition to making existing scars less noticeable, laser therapy can be used prophylactically to minimize postoperative scarring.[20] For symptomatic scars, lasers can reduce pruritus and pain. Lastly, laser treatment can increase the range of motion of debilitating scars that restrict movement.

Enhancing Healthcare Team Outcomes

Effective laser revision of scars requires a multidisciplinary approach to optimize patient outcomes, minimize complications, and enhance patient satisfaction. Physicians and advanced practitioners must thoroughly understand laser physics, scar pathophysiology, and patient selection criteria to tailor treatments effectively. Nurses are crucial in preprocedural preparation, patient education, and posttreatment wound care, ensuring adherence to laser safety protocols and infection prevention measures. Pharmacists contribute by advising on prophylactic antiviral therapy for patients with a history of herpes simplex virus, as well as recommending adjunctive treatments such as topical retinoids, corticosteroids, or depigmenting agents to improve healing and reduce hyperpigmentation.

Interprofessional communication and care coordination are essential in developing a comprehensive, patient-centered treatment plan. Regular collaboration among dermatologists, plastic surgeons, rehabilitation specialists, and primary care providers ensures continuity of care, particularly for patients with complex scars or underlying conditions that may impact healing. Standardized protocols for patient assessment, including scar classification, Fitzpatrick skin typing, and objective measurements, facilitate consistent documentation and treatment monitoring. By integrating evidence-based laser therapy with supportive interventions, healthcare teams can enhance procedural success, improve safety, and achieve optimal functional and aesthetic outcomes for patients undergoing scar revision.

Nursing, Allied Health, and Interprofessional Team Monitoring

Considerations for interprofessional team monitoring include the following:

• Vital signs
• Wound care
• Monitor for signs of infection
• Monitor for signs of skin irritation