Assessment of laser-assisted delivery vs intralesional injection of botulinum toxin A in treatment of hypertrophic scars and keloids

A Comprehensive Review of Non-Surgical Treatments for Hypertrophic and Keloid Scars in Skin of Color

Hypertrophic and keloid scars are fibroproliferative growths resulting from aberrant wound healing. Individuals with Fitzpatrick skin types (FSTs) IV-VI are particularly predisposed to hypertrophic and keloid scarring, yet specific guidelines for these populations are still lacking within the literature. Therefore, this comprehensive review provides a list of various treatments and considerations for hypertrophic and keloid scarring in patients with skin of color. We constructed a comprehensive PubMed search term and performed quadruple-blinded screening on all resulting studies to achieve this objective. Our findings demonstrate 1) the lack of efficacious treatments for raised scars within this population and 2) the need to empirically investigate individualized and multimodal therapeutic options for those with skin of color.

Pharmacotherapy for Keloids and Hypertrophic Scars

Keloids (KD) and hypertrophic scars (HTS), which are quite raised and pigmented and have increased vascularization and cellularity, are formed due to the impaired healing process of cutaneous injuries in some individuals having family history and genetic factors. These scars decrease the quality of life (QOL) of patients greatly, due to the pain, itching, contracture, cosmetic problems, and so on, depending on the location of the scars. Treatment/prevention that will satisfy patients' QOL is still under development. In this article, we review pharmacotherapy for treating KD and HTS, including the prevention of postsurgical recurrence (especially KD). Pharmacotherapy involves monotherapy using a single drug and combination pharmacotherapy using multiple drugs, where drugs are administered orally, topically and/or through intralesional injection. In addition, pharmacotherapy for KD/HTS is sometimes combined with surgical excision and/or with physical therapy such as cryotherapy, laser therapy, radiotherapy including brachytherapy, and silicone gel/sheeting. The results regarding the clinical effectiveness of each mono-pharmacotherapy for KD/HTS are not always consistent but rather scattered among researchers. Multimodal combination pharmacotherapy that targets multiple sites simultaneously is more effective than mono-pharmacotherapy. The literature was searched using PubMed, Google Scholar, and Online search engines.

Application of fractional carbon dioxide laser monotherapy in keloids: A meta-analysis

BACKGROUND

There is no evidence-based guidance on the use of fractional CO2 laser in the excision of scars.

AIM

To explore the effectiveness and safety of fractional CO2 laser in the treatment of keloids.

METHODS

In this meta-analysis, we searched the PubMed, Embase, and Cochrane databases from inception to April 2023. We only included studies reporting fractional CO2 laser treatment of keloids. We excluded duplicate published studies, incomplete studies, those with incomplete data, animal experiments, literature reviews, and systematic studies.

RESULTS

The pooled results showed that the Vancouver Scar Scale (VSS) parameters of height weighted mean difference (WMD) = -1.10, 95% confidence interval (CI): -1.46 to -0.74), pigmentation (WMD = -0.61, 95% CI: -1.00 to -0.21), and pliability (WMD = -0.90, 95% CI: -1.17 to -0.63) were significantly improved after fractional CO2 laser treatment of keloids. However, vascularity did not significantly change. Additionally, the total VSS was significantly improved after treatment (WMD = -4.01, 95% CI: -6.22 to -1.79). The Patient Scars Assessment Scale was significantly improved after treatment (WMD = -15.31, 95% CI: -18.31 to -12.31). Regarding safety, the incidences of hyperpigmentation, hypopigmentation, pain, telangiectasia, and atrophy were 5%, 0%, 11%, 2% (95% CI: 0%-6%), and 0% (95% CI: 0%-4%), respectively.

CONCLUSIONS

Fractional CO2 laser is effective in the treatment of keloids and can effectively improve the height, pigmentation, and pliability of scars, and patients are satisfied with this treatment. Further studies should explore the role of combination therapy.

Hypertrophic Scars and Keloids: Advances in Treatment and Review of Established Therapies

Hypertrophic scars and keloids can have significant detrimental effects on patients both psychosocially and functionally. A careful identification of patient risk factors and a comprehensive management plan are necessary to optimize outcomes. Patients with a history of dystrophic scarring should avoid unnecessary procedures and enhance the wound-healing process using various preventive strategies. As there is no single, fully efficacious treatment modality, prevention remains the best approach in reducing aberrant scar formation. When prevention therapies fail, keloids have been shown to be respond to a variety of therapies including topical and injectable corticosteroids, 5-fluorouracil, radiotherapy, lasers, and surgical excision, all with varying efficacies. As such, management should be tailored to the individual patient's risk factors with the use of combination therapies to reduce recurrence rates. Still, keloid and hypertrophic scar therapies are widely diverse with novel treatment modalities providing alternatives for recurring lesions. Laser-assisted drug delivery, skin priming, and novel topical therapies may provide alternative options for the management of hypertrophic scars and keloids.

Laser-Assisted Drug Delivery in the Treatment of Scars, Rhytids, and Melasma: A Comprehensive Review of the Literature

Although broad reviews on laser-assisted drug delivery (LADD) have been published in the past, an updated focused examination of its utility in the context of common, treatment-resistant, dermatologic conditions has not been published. This article reports a comprehensive scoping review of the potential benefits of LADD compared to laser or drug monotherapy for the treatment of 3 such conditions: scars, rhytids, and melasma. A PubMed (National Institutes of Health; Bethesda, MD) search was conducted for keywords including "laser-assisted drug delivery," "scar," "rhytid," and "melasma." Out-of-scope studies were excluded. To evaluate the efficacy of LADD for the treatment of scars, relevant articles were categorized by scar type: hypertrophic/keloid, atrophic, and hypopigmented. LADD, with both ablative and nonablative laser types, was studied in combination with corticosteroids, botulinum toxin-A (BTX-A), 5-fluorouracil, 5-aminolevulinic acid photodynamic therapy, stem cells, platelet-rich plasma, and prostaglandin analogs for the treatment of scars. Some randomized controlled trials demonstrated the efficacy of LADD, whereas others showed no significant differences in clinical outcomes but demonstrated reduced adverse effects. Regarding rhytids, laser treatment has been combined with various cosmeceuticals, including poly-L-lactic acid, topical retinaldehyde, and topical BTX-A. The studies reviewed supported the use of LADD with these drugs over monotherapy. Some studies showed that LADD was effective for the absorption of drugs such as poly-L-lactic acid and BTX-A which are often not effective topically. For melasma treatment, LADD with tranexamic acid and hydroquinone was superior in some studies, but not significantly different than monotherapy in other studies. LADD with certain drugs could be considered to treat scars, rhytids, and melasma.

LEVEL OF EVIDENCE: 5

Laser-Assisted Drug Delivery: A Systematic Review of Safety and Adverse Events

Laser-assisted drug delivery (LADD) is an increasingly studied and applied methodology for drug delivery. It has been used in a wide variety of clinical applications. Given the relatively low barrier to entry for clinicians as well as ongoing research in this area, the authors aimed to review outcomes relating to safety in laser-assisted drug delivery. A systematic review was conducted, with the databases PubMed, Medline and Embase searched in September 2022. Included articles were those that mentioned laser-assisted drug delivery in human subjects that also reported adverse effects or safety outcomes. There were no language-based exclusions. Conference abstracts and literature reviews were excluded. The results were then tabulated and categorized according to the application of LADD. In total, 501 articles were obtained. Following deduplication, screening, and full text review 70 articles of various study designs were included. Common findings were erythema, oedema, pain, and crusting following LADD. Several notably more severe adverse effects such as generalized urticaria, infection, scarring and dyspigmentation were noted. However, these events were varied depending on the clinical use of LADD. Relevant negatives were also noted whereby no studies reported life-threatening adverse effects. Limitations included limited details regarding the adverse effects within the full texts, lack of follow-up, and risk of bias. In conclusion, there were multiple adverse effects that clinicians should consider prior to carrying out LADD, where treatment goals and patient tolerability should be considered. Further evidence is needed to quantitatively determine these risks.

A systematic review of randomised controlled trials investigating laser assisted drug delivery for the treatment of keloid and hypertrophic scars

The objective of this article is to study the clinical efficacy and adverse events of laser-assisted drug delivery in the treatment of hypertrophic and keloid scars. We searched the following databases up to 22 October 2020: the Cochrane Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials (Clinical Trials) in The Cochrane Library, MEDLINE, EMBASE, and reference lists of articles for randomised clinical trials (RCTs) of laser-assisted drug delivery for the treatment of hypertrophic and keloid scars. We also searched online trials registries for ongoing trials and contacted trial authors where appropriate. Our outcomes of interest were objective clinical evaluation of scars, participant satisfaction, and adverse effects of the treatments. Two authors independently extracted data and assessed trial quality using Cochrane Risk of Bias 2. Two authors independently abstracted data. We included 10 RCTs involving a total of 329 participants: six trials utilised parallel-arm RCTs whilst four employed split-scar design. Three trials had high risk of bias with the remaining seven rated as having some concerns. The interventions and outcomes were too varied to be combined statistically. High-quality randomised controlled trials assessing laser-assisted delivery for drugs in the context of hypertrophic and/or keloid scarring are needed. Studies with a larger number of participants, with longer follow-up times, and standardised evaluation of outcome and adverse effects are warranted.

Microdroplet botulinum toxin: A review

Microbotox is the administration of multiple microdroplets of botulinum toxin in intradermal plane. It is increasingly becoming popular owing to its more favorable outcome and better safety profile than the conventional technique. The intention is to treat fine lines and wrinkles without imparting an undesired “frozen face like” appearance. Besides facial rejuvenation, it has found its way into the management of other indications such as rosacea, hyperhidrosis, keloid, and seborrhea. Being a relatively newer method, knowledge about the various dilution methods, desired volume, and correct depth of injection involved in this technique remain scarce. In this article, the authors have highlighted various indications, procedures, adverse effects, and contraindications of microbotox.

Safety and efficacy of botulinum toxin type A in preventing and treating scars in animal models: A systematic review and meta-analysis

Previous studies have used botulinum toxin type A (BTXA) to improve postoperative and hypertrophic scars; however, there is lack of detailed verification on the safety and effectiveness of this approach. This study aimed to evaluate the therapeutic effect of BTXA on postoperative hypertrophic scars and its influence on cytokine expression in animal models. A computerised search of different databases was performed, including PubMed, Web of Science, Scopus, Cochrane, Embase, CNKI, and Wanfang, up to 10 March 2021. A meta-analysis was performed using R 4.0.0 based on hypertrophic index, epithelialisation time, wound area, and vascular endothelial growth factor (VEGF) expression. Eleven studies were included. The meta-analysis showed a significant difference in hypertrophic index (standardised mean difference [SMD] = -2.63, 95% confidence interval [CI]: -3.50 to -1.76, P < .01), wound area (SMD = -0.54, 95% CI: -1.24 to 0.16, P < .01), and VEGF expression (SMD = -2.56, 95% CI: -3.50 to -1.62, P < .01). This study shows that BTXA is safe and effective in preventing and treating scar hypertrophy in animal models, but excessive doses of BTXA and BTXA to treat large areas should be avoided.

Botulinum toxin and platelet rich plasma as innovative therapeutic modalities for keloids

Keloids characterize a definitely challenging type of cutaneous scars for which a diversity of therapeutic modalities has been suggested. The aim of this work was to compare the therapeutic efficacy of intralesional injection of botulinum toxin type-A (BTX-A), platelet rich plasma (PRP), and triamcinolone acetonide (TAC) in keloids. A total of 60 keloids patients were enrolled and divided randomly into three equal groups. Group I treated by intralesional BTX-A injection, group II treated by intralesional PRP injection, and group III treated by intralesional TAC injection. Clinical assessment was done by Vancouver Scar Scale (VSS), Verbal Rating Scale (VRS), and dermoscopic examination. Additionally, histopathology and immunohistochemistry of connective tissue growth factor (CTGF) expression were evaluated. The results of this study revealed significant improvement of both VSS and VRS in response to all treatment modalities. There was significant improvement of VSS in BTX-A and PRP groups more than TAC group. However, no significant difference observed between BTX-A and PRP groups. Immunohistochemical examination showed significant decrease of CTGF expression after treatment in BTX-A and PRP groups more than TAC group. In conclusion, both BTX-A and PRP could yield a chance for cosmetically better outcomes in keloids treatment than conventional TAC injection.

Effect of Artesunate Combined With Fractional CO2 Laser on the Hypertrophic Scar in a Rabbit Model

BACKGROUND AND OBJECTIVES

Hypertrophic scar (HS), a common complication in wound healing, is characterized by the disarrangement of collagen, fibers, and extracellular matrix. Artesunate (ART) can inhibit the abnormal formation of fibroblasts and collagens. Fractional CO2 laser (FCO2 L) can facilitate tissue remodeling and the absorption of drugs into ablative microthermal columns in HS. So far, no research has investigated the efficacy of ART combined with an FCO2 L in treating HS. To investigate the theoretical basis and clinical significance of this combination, we established a rabbit model of HS to observe the change in the expression of transforming growth factor β1 (TGF-β1) and proliferating cell nuclear antigen (PCNA).

STUDY DESIGN/MATERIALS AND METHODS

Forty New Zealand white rabbits were randomly divided into four groups: control group, ART group, FCO2 L group, and ART + FCO2 L (combination) group. Four wounds were surgically established in the ear of each rabbit and allowed to develop into HS. ART (20 μL/cm2 ) was injected in ART and combination groups, and FCO2 L (combo mode, deep energy:10m J, super energy: 50 mJ) in FCO2 L and combination groups on the 28th day after HS occurred. Three rounds of treatment were applied (once every 14 days). HS samples were measured by hematoxylin and eosin staining, Van Gieson staining, immunohistochemistry, and Western blot analysis on the 70th day.

RESULTS

The morphological and histopathological changes in HS were significant. HSs were smoother and smaller and the collagen fibers were thinner and less disordered in the combination group than those in ART and FCO2 L groups. Meanwhile, the hypertrophic index (HI), fiber density (NA), and collagen fiber content (AA) were lower in the combination group (1.54 ± 0.15, 3.30 ± 0.22, 30.37 ± 1.41%) than in the ART group (2.51 ± 0.22, 4.69 ± 0.16, 44.68 ± 2.30%) and FCO2 L group (1.99 ± 0.14, 4.13 ± 0.12, 37.74 ± 1.38%) (P < 0.01). Additionally, the expressions of TGF-β1 and PCNA protein were suppressed in the ART group (0.30 ± 0.03, 0.25 ± 0.03) and FCO2 L group (0.35 ± 0.03, 0.32 ± 0.05), and the suppression was more significant in the combination group(0.07 ± 0.02, 0.07 ± 0.02) (P < 0.01).

CONCLUSIONS

The combination of ART and FCO2 L can effectively reduce HS in the rabbit model. This is the first report about this combination in the treatment of HS. A novel treatment is expected to be based on our findings. Lasers Surg. Med. © 2021 Wiley Periodicals LLC.