Efficacy of Botulinum Toxin Type A in Improving Scar Quality and Wound Healing: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Biological study of skin wound treated with Alginate/Carboxymethyl cellulose/chorion membrane, diopside nanoparticles, and Botox A

A hydrogel-based wound dressing with desirable properties is necessary for achieving functional skin integrity post-injury. This study focuses on preparing a hydrogel using Alginate/Carboxymethyl cellulose (Alg/CMC) as a base material. To evaluate its regenerative effects on full-thickness wounds, diopside nanoparticles and Botulinum toxin A (BTX-A) were incorporated into the hydrogel along with chorion membrane. The diopside nanoparticles (DNPs) act as a proangiogenic factor, promoting proliferation and regulating inflammation, while the chorion membrane facilitates these processes. Additionally, BTX-A prevents scar formation and aids in wound closure. The nanoparticles and hydrogel were characterized using various techniques, and their cytocompatibility was assessed. In vivo studies and quantitative polymerase chain reaction analysis showed that wound area reduction was significant after two weeks of treatment with the Alg/CMC/ChNPs/DNPs/BTX-A hydrogel. Overall, this scaffold demonstrated potential for promoting tissue regeneration and new epithelization formation, making it a promising candidate for enhancing skin restoration in wound treatments.

Quantitative Assessment of the Effects of Botulinum Toxin on Skin Perfusion by Laser Doppler Flowmetry: A Clinical Trial

Several studies reported an increase in skin glow, pore shrinkage, and an improvement in oily skin with its mesobotox-like use. The authors aimed to determine the extent of late changes in skin perfusion in the superficial dermis when Botulinium toxin A (Btx-A) is injected into the skin with mesotherapy, independent of any stimulant and surgery, using a laser Doppler flowmeter for analysis. Btx-A was applied to the right cheek and saline mesotherapy to the left cheeks of a total of 9 subjects. Two weeks later, their contribution to skin circulation was measured by the laser Doppler flowmeter. Although it was more on the side where Btx-A was applied, an increase in vascularity was observed on both sides of the subjects and no statistical difference could be found between the right and left cheeks in the late period.

Current Research of Botulinum Toxin Type A in Prevention and Treatment on Pathological Scars

BACKGROUND

Dermatologists have been looking for ways to improve wound healing and postoperative scar appearance. The safety and efficacy of botulinum toxin type A (BTXA) in the prevention and treatment on pathological scars have become the current research hotspot since it was approved by the US FDA in medical cosmetology in 2002.

PURPOSE

This article aims to provide an overview of the clinical research, limitations, and application prospects of BTXA in the prevention and treatment of traumatic or postoperative pathological scars, which can provide a reference and better understanding of relevant studies.

METHODS

The current research progress was summarized and discussed, with new problems and research ideas being proposed ranging from the molecular mechanism of BTXA in preventing and treating pathological scars to its clinical application via investigation and reference research.

RESULTS

BTXA is effective in relieving itching and pain associated with pathological scars, limiting scar hyperplasia along with preventing scar contracture, but the specific mechanism is still not clear.

CONCLUSION

Most of the clinicians have confirmed the clinical effectiveness of BTXA in the prevention and treatment of pathological scars, yet its mode of action and combination therapy need more research.

Concentration-Dependent Inhibition of Hypertrophic Scar Formation by Botulinum Toxin Type A in a Rabbit Ear Model

BACKGROUND

Hypertrophic scar (HS), as a disappointing result of wound healing, adversely affects the patient, both physically and psychologically. Botulinum toxin type A (BTXA) has been revealed to prevent and improve HS. We conducted this study to assess the effect of different BTXA concentrations on inhibiting HS in a rabbit ear model.

METHODS

Eight healthy New Zealand long-eared rabbits were included in the experiment for modeling. Four wounds of 1 cm in diameter were created on both ears, which separately received an injection of a given BTXA concentration immediately after surgery. On postoperative days 40, scar tissue was obtained and subjected to hematoxylin and eosin (HE) staining for the hypertrophic index (HI) and immunohistochemical staining for CD31, Ki67, and transforming growth factor-beta 1 (TGF-β1) expression. The HI was assessed for scar proliferation, and CD31 and Ki67 expression were used to assess the effect of BTXA on angiogenesis and fibroblast proliferation, respectively.

RESULTS

All rabbits healed well without infection or mortality. From the HE staining, the HI showed a significant decrease with increasing BTXA concentration (p < 0.05). BTXA also inhibited angiogenesis and TGF-β1 expression in a concentration-dependent manner, with significant differences between the groups (p < 0.05). BTXA inhibited fibroblast proliferation with increasing BTXA concentration. However, there was no significant difference between the 0.5 U/0.1 ml and 0 U/0.1 ml groups (p > 0.05).

CONCLUSION

Immediate postoperative BTXA injection inhibited angiogenesis, fibroblast proliferation, and TGF-β1 expression in a concentration-dependent manner, thus suppressing HS formation in rabbit ears.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors https://www.springer.com/journal/00266 .

Botulinum toxin A in dentistry and orofacial surgery: an evidence-based review - part 1: therapeutic applications

Objective An evidence-based review on the safety and efficacy of botulinum toxin type-A (BoNTA) in orofacial conditions, focusing on the therapeutic applications and role of BoNTA as an adjuvant treatment.Data source and selection Data was collected using PubMed (Medline), Cochrane Library of Systematic Reviews and Cochrane Central Register of Controlled Trials electronic databases. Having satisfied the search parameters, 32 studies for therapeutic applications and 26 for BoNTA as an adjunctive treatment were included. The quality of relevant studies was assessed using the Best Evidence Topics (BETs) Critical Appraisal Tool.Data extraction The highest level of evidence (LOE) behind BoNTA safety and efficacy was for wound healing and scar management in the orofacial surgery context, where BoNTA was presented as an adjunctive modality. Level-I evidence was controversial for temporomandibular disorders and bruxism. However, it showed promising results for painful temporomandibular disorders of myogenic origin refractory to conservative therapies, and to decrease muscle contraction intensity in sleeping bruxism. There was only one level-II study for persistent recurrent aphthous stomatitis. Data showed limited level-III evidence for orofacial pain conditions (temporomandibular joint recurrent dislocation and pain, burning mouth syndrome or atypical odontalgia), oral cancer complications, or as an adjuvant to maxillofacial and orthognathic surgeries. Benefits of BoNTA in prosthodontics had weak level-IV evidence. No evidence was found among the periodontology field.Conclusion There is growing evidence to support the safety and efficacy of BoNTA in the investigated orofacial pathological conditions, with high levels of satisfaction from the patient and clinician perspective. However, there are some inconsistencies and limited high-quality evidence available. Well-designed controlled clinical trials are necessary to evaluate long-term safety, efficacy and cost-effectiveness before BoNTA is widely adopted with irrefutable evidence-based clinical guidelines.

Efficacy and safety of botulinum toxin type A for postoperative scar prevention and wound healing improvement: A systematic review and meta-analysis

BACKGROUND

Botulinum toxin type A (BTXA) has shown underlying effects for wound healing improvement. New small clinical trials keep emerging every year and updated evidence-based information is warranted. This study aimed to evaluate the efficacy and safety of BTXA for preventing scarring.

METHODS

Four databases were searched to recruit randomized clinical trials (RCTs) which compared the surgical wounds treated with BTXA vs. those treated with placebo or blank control. The outcomes were primarily quantified by measures including the Vancouver Scar Scale (VSS), Visual Analog Scale (VAS), Stony Brook Scar Evaluation Scales (SBSES), modified SBSES (mSBSES), and scar width. Patients' satisfaction and adverse events were also reported.

RESULTS

In total, 16 RCTs involving 671 cases (510 patients) were included. The outcome showed significant superiority of BTXA in VSS (mean difference [MD] = -1.32, 95% confidence interval [CI]: -2.00 to -0.65, p = 0.0001), VAS (MD = 1.29, 95% CI: 1.05-1.52, p < 0.00001), SBSES or mSBSES (MD = -0.18, 95% CI: -0.27 to -0.10, p < 0.0001), scar width (MD = -0.18, 95% CI: -0.27 to -0.10, p < 0.0001), and patients' satisfaction (risk ratio [RR] = 1.25, 95% CI: 1.06-1.49, p = 0.01). No significant difference of adverse events incidence was observed (RR = 1.46 95% CI: 0.64-3.33, p = 0.36).

CONCLUSIONS

Botulinum toxin type A is effective and safe for postoperative scar prevention and wound healing improvement, especially for facial wounds of Asians. Further studies should manage to standardize the treatment algorithm, while mSBSES is recommended for scar assessment.

Efficacy of Botulinum Toxin A for Scar Prevention After Breast Augmentation: A Randomized Double-Blind Intraindividual Controlled Trial

BACKGROUND

Botulinum toxin A benefits postsurgical scar prevention by reducing wound edge tension and inhibiting in vitro scar tissue fibrosis.

OBJECTIVE

To investigate the efficacy of botulinum toxin Type A (BTX) in improving inframammary scar appearance after primary breast augmentation.

MATERIALS AND METHODS

A prospective, double-blinded, randomized controlled trial was performed with 27 participants receiving primary augmentation mammoplasty with inframammary incisions. After skin closure, intradermal injections of BTX were administered to 1 (treated) side of the inframammary incision. The contralateral side was the control. Scars were evaluated at 3 months, 6 months, and 9 months using the Patient and Observer Scar Assessment Scale and multispectral imaging analysis.

RESULTS

Overall, 22 patients completed the study. There were no significant subjective differences between the treated and control sides except the patient's treated side had significantly higher scores than the control side at 9 months. The treated side showed significantly smaller scar widths at 6 months and 9 months (p < .001) and better scar surface textures at 9 months (p = .003) than the control side.

CONCLUSION

Subjectively, intradermal BTX injection immediately after breast augmentation skin closure caused no significant differences. Objectively, scar width and texture significantly improved at 6 months and 9 months.

Synergic Effect of Botulinum Toxin Type A and Triamcinolone Alleviates Scar Pruritus by Modulating Epidermal Hyperinnervation: A Preliminary Report

BACKGROUND

Patients often experience scar-related pruritus, which adversely affects quality of life. Triamcinolone acetonide (TAC) is widely used to treat pathologic scars, and botulinum toxin type A (BTX-A) reportedly improves scarring and associated discomfort.

OBJECTIVES

The aim of this study was to investigate the clinical efficacy of combining TAC and BTX-A to reduce scar itch; potential mechanisms were investigated via an animal model.

METHODS

For the clinical study, each scar on a patient was divided into 2 equal parts, with one part receiving TAC/BTX-A and the other TAC alone. Therapeutic interventions were administered over 3 sessions at 4-week intervals. Itch intensity was measured on a visual analog scale before each therapeutic intervention (V1, V2, V3) and 4 weeks after the last intervention (V4). For the animal model, rats were allocated into 5 groups: control, untreated burn, TAC, BTX-A, and TAC/BTX-A. We evaluated alloknesis in the right hind paw and analyzed possible molecular mechanisms.

RESULTS

In humans, TAC/BTX-A significantly reduced scar itch compared with TAC alone at V4 (P = 0.04). In rats, post-burn itch was mitigated at 4 weeks after treatment with TAC, BTX-A, and TAC/BTX-A (P = 0.03, P = 0.0054, and P = 0.0053, respectively). TAC/BTX-A significantly decreased the density of intraepidermal nerve fibers post-burn relative to the untreated burn (P = 0.0008). TAC/BTX-A downregulated the expressions of nerve growth factor and protein transient receptor potential vanilloid subtype 1.

CONCLUSIONS

TAC/BTX-A therapy exhibited enhanced and sustained clinical efficacy in relieving scar itch, possibly via modulating epidermal innervation and expression of transient receptor potential vanilloid subtype 1 .

LEVEL OF EVIDENCE: 2

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.

The Efficacy of Drug Injection in the Treatment of Pathological Scar: A Network Meta-analysis

BACKGROUND

Pathological scars mainly include hyperplastic scars and keloids, and there is no uniform treatment standard for the treatment of pathological scar in clinic now. Drug injection in the treatment of pathological scar is widely used because of its advantages of less trauma and simple operation. Therefore, we used a network meta-analysis to compare the curative effect of four kinds of drugs which are commonly used in the treatment of pathological scar such as botulinum toxin type A, corticosteroids (including diprospan and triamcinolone acetonide (TAC)), verapamil and 5-fluorouracil (5-FU), systematically. It is hoped that our study will provide evidence for the choice of drugs in the treatment of pathological scar by injection.

METHODS

Relevant articles from Wanfang, VIP, CNKI, PubMed, Cochrane Library and Embase databases were extracted by us. They were included into a network meta-analysis to compare the four kinds of drugs which are commonly used in the treatment of pathological scar.

RESULTS

The network meta-analysis included a total of 1513 patients from 23 studies. Through meta-analysis, we found that the efficacy of botulinum toxin type A combined with corticosteroid drugs was best in the treatment of pathological scar by injection. There was no significant difference between botulinum toxin type A, corticosteroids combined with 5 Fu, verapamil and 5-FU. The efficacy of corticosteroids combined with 5-FU was better than that of corticosteroids alone and verapamil alone, but there was no significant difference between them and 5-FU. Further, the order of efficacy predicted by the SUCRA curve was as follows: botulinum toxin type A combined with corticosteroids > corticosteroids combined with 5-FU > botulinum toxin type A > corticosteroids > 5-FU > verapamil. Moreover, no publication bias was found in the funnel diagram.

CONCLUSION

In the injection treatment of pathological scar, we recommend the combined injection of two drugs, especially botulinum toxin type A combined with corticosteroids. The effective treatment of botulinum toxin type A combined with corticosteroids in the treatment of pathological scar is as follows: Patients were treated once monthly with intralesional injection of TAC (0.1 ml/cm³) mixed with botulinum toxin type A (2.5 IU/cm³) for a total of 3 treatments. However, there are still limitations in this network meta-analysis, and its conclusion still needs to be further confirmed by more randomized controlled trials.

LEVEL OF EVIDENCE III

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 .

Botulinum Toxin Type A Injection for Mammoplasty and Abdominoplasty Scar Management: A Split-Scar Double-Blinded Randomized Controlled Study

BACKGROUND

Scars are inevitable results of surgical procedures, and prevention of them is still a major problem in the field of cosmetic surgery. Although various studies have been performed on botulinum toxin-A (BoNT-A) injection for the prevention of hypertrophic scars, the exact mechanism remains unclear.

METHODS

This prospective, double-blinded, randomized study was performed on 19 patients who underwent mammoplasty and abdominoplasty surgery in Razi Hospital from October 2018 to December 2019. Single session of treatment was performed, where XEOMIN was allocated to one half of the scar and 0.9% saline to the control half. 3 and 6 months later, scars were assessed using the modified Stony Brook Scar Evaluation Scale (SBSES).

RESULTS

In total, 19 patients who completed the study were analyzed. mSBSES at the third month (P value < 0.001; 3.34 ± 1.59 vs 1.5 ± 1.36) and the sixth month (P value < 0.001; 4.89 ± 1.83 vs 2.39 ± 1.82) showed a significant difference between the treatment and control groups. In the subset analysis, there was significant difference between BoNT-A and control in all four items including width, height, color, and scar visibility at months 3 and 6, and the BoNT-A-treated sides had higher scores in all items.

CONCLUSION

BoNT-A has a significant effect on scar prevention due to mammoplasty and abdominoplasty compared to placebo and results in decreased erythema, height, width and reduces incision line visibility. Moreover, its effect increases significantly over time from months 3 to 6.

LEVEL OF EVIDENCE II

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 .