Improved Scar Outcomes with Increased Daily Duration of Pressure Garment Therapy

Manufacture and use of transparent facial orthotic masks for treating facial burn scars: A systematic review

BACKGROUND

Custom-made transparent facial orthoses (TFOs) (face masks) are used to improve facial burn scars. We conducted a systematic literature review on TFO manufacture and use.

METHODS

Pubmed and Cochrane databases were searched without restrictions for relevant articles. TFO manufacture details and use according to international recommendations (20-32 mmHg pressure, TFO worn 20-23 h/day for ≥2 months) were extracted.

RESULTS

Of 279 retrieved articles, 11 published over the last 41 years (four in the last 5 years) discussed TFO manufacture/use. There were five technical notes, five case reports, and a patient-cohort study (total patients in the studies=21). TFO-manufacture methods could be categorized as classical, digital, or mixed classical-digital. Relative clinical efficacies and cost advantages were unclear. The plastics used, harness materials, harness-point number, and silicone-interface use differed from study to study. Target pressure, actual pressure, expected daily wearing time, and treatment duration ranged widely and often did not meet current guidelines. Actual wearing time and treatment duration were never measured.

CONCLUSIONS

Although TFOs play an important global role in burn care, there is a grave paucity of research. Further research is needed to promote the standardization of TFO-related practices and thereby improve the outcomes of facial-burn patients.

NRP1 transduces mechanical stress inhibition via LATS1/YAP in hypertrophic scars

Hypertrophic scar (HS) is an abnormal fibrous hyperplasia of the skin caused by excessive tissue repair in response to skin burns and trauma, which restricts physical function and impairs patients' quality of life. Numerous studies have shown that pressure garment therapy (PGT) is an effective treatment for preventing hypertrophic scars. Herein, we found that mechanical stress stimulates the neuropilin 1 (NRP1) expression through screening GSE165027, GSE137210, and GSE120194 from Gene Expression Omnibus (GEO) database and bioinformatics analysis. We verified this stimulation in the human hypertrophic scar, pressure culture cell model, and rat tail-scar model. Mechanical compression increased LATS1 and pYAP enrichment, thus repressing the expression of YAP. Functionally, the knockdown of NRP1 promoted the expression of LATS1, thus decreasing the expression of YAP and inhibiting endothelial cell proliferation. Furthermore, co-immunoprecipitation analysis confirmed that NRP1 binds to YAP, and mechanical compression disrupted this binding, which resulted in the promotion of YAP relocation to nuclear. In conclusion, our results indicated that NRP1 transduces mechanical force inhibition by inhibiting YAP expression. Mechanical pressure can release YAP bound to NRP1, which explains the phenomenon that mechanical stress increases YAP in the nucleus. Strategies targeting NRP1 may promote compression therapy with optimal and comfortable pressures.

Scar Management and Dyschromia: A Summary Report from the 2021 American Burn Association State of the Science Meeting

Burn scars, and in particular, hypertrophic scars, are a challenging yet common outcome for survivors of burn injuries. In 2021, the American Burn Association brought together experts in burn care and research to discuss critical topics related to burns, including burn scars, at its State of the Science conference. Clinicians and researchers with burn scar expertise, as well as burn patients, industry representatives, and other interested stakeholders met to discuss issues related to burn scars and discuss priorities for future burn scar research. The various preventative strategies and treatment modalities currently utilized for burn scars were discussed, including relatively noninvasive therapies such as massage, compression, and silicone sheeting, as well as medical interventions such as corticosteroid injection and laser therapies. A common theme that emerged is that the efficacy of current therapies for specific patient populations is not clear, and further research is needed to improve upon these treatments and develop more effective strategies to suppress scar formation. This will necessitate quantitative analyses of outcomes and would benefit from creation of scar biobanks and shared data resources. In addition, outcomes of importance to patients, such as scar dyschromia, must be given greater attention by clinicians and researchers to improve overall quality of life in burn survivors. Herein we summarize the main topics of discussion from this meeting and offer recommendations for areas where further research and development are needed.

Clinical Utility of the Portable Pressure-Measuring Device for Compression Garment Pressure Measurement on Hypertrophic Scars by Burn Injury during Compression Therapy

Compression therapy for burn scars can accelerate scar maturation and improve clinical symptoms (pruritus and pain). This study objectively verified the effect of pressure garment therapy in maintaining a therapeutic pressure range for hypertrophic scars. Sixty-five participants (aged 20~70 years) with partial- or full-thickness burns, Vancouver scar scale score of ≥4, and a hypertrophic scar of ≥4 cm × 4 cm were enrolled. Compression pressure was measured weekly using a portable pressure-monitoring device to regulate this pressure at 15~25 mmHg for 2 months. In the control group, the compression garment use duration and all other burn rehabilitation measures were identical except for compression monitoring. No significant difference was noted in the initial evaluations between the two groups (p > 0.05). The improvements in the amount of change in scar thickness (p = 0.03), erythema (p = 0.03), and sebum (p = 0.02) were significantly more in the pressure monitoring group than in the control group. No significant differences were noted in melanin levels, trans-epidermal water loss, or changes measured using the Cutometer® between the two groups. The efficacy of compression garment therapy for burn-related hypertrophic scars can be improved using a pressure-monitoring device to maintain the therapeutic range.

Proceedings of the 2021 American Burn Association State and Future of Burn Science Meeting

Periodically, the American Burn Association (ABA) has convened a State of the Science meeting on various topics representing multiple disciplines within burn care and research. In 2021 at the request of the ABA President, meeting development was guided by the ABA's Burn Science Advisory Panel (BSAP) and a subgroup of meeting chairs. The goal of the meeting was to produce both an evaluation of the current literature and ongoing studies, and to produce a research agenda and/or define subject matter-relevant next steps to advance the field(s). Members of the BSAP defined the topics to be addressed and subsequently solicited for nominations of expert speakers and topic leaders from the ABA's Research Committee. Current background literature for each topic was compiled by the meeting chairs and the library then enhanced by the invited topic and breakout discussion leaders. The meeting was held in New Orleans, LA on November 2nd and 3rd and was formatted to allow for 12 different topics, each with two subtopics, to be addressed. Topic leaders provided a brief overview of each topic to approximately 100 attendees, followed by expert-lead breakout sessions for each topic that allowed for focused discussion among subject matter experts and interested participants. The breakout and topic group leaders worked with the participants to determine research needs and associated next steps including white papers, reviews and in some cases collaborative grant proposals. Here, summaries from each topic area will be presented to highlight the main foci of discussion and associated conclusions.

Traditional Chinese medicine for hypertrophic scars—A review of the therapeutic methods and potential effects

Hypertrophic scar (HS) is a typical pathological response during skin injury, which can lead to pain, itching, and contracture in patients and even affect their physical and mental health. The complexity of the wound healing process leads to the formation of HS affected by many factors. Several treatments are available for HS, whereas some have more adverse reactions and can even cause new injuries with exacerbated scarring. Traditional Chinese Medicine (TCM) has a rich source, and most botanical drugs have few side effects, providing new ideas and methods for treating HS. This paper reviews the formation process of HS, the therapeutic strategy for HS, the research progress of TCM with its relevant mechanisms in the treatment of HS, and the related new drug delivery system of TCM, aiming to provide ideas for further research of botanical compounds in the treatment of HS, to promote the discovery of more efficient botanical candidates for the clinical treatment of HS, to accelerate the development of the new drug delivery system and the final clinical application, and at the same time, to promote the research on the anti-HS mechanism of multiherbal preparations (Fufang), to continuously improve the quality control and safety and effectiveness of anti-HS botanical drugs in clinical application.

Skin scarring: Latest update on objective assessment and optimal management

Although skin scarring is considered by some to be a minor, unavoidable consequence in response to skin injury, for many patients, cosmetically unsightly scars may cause uncomfortable symptoms and loss of function plus significant psycho-social distress. Despite their high prevalence and commonality, defining skin scars and their optimal management has proven problematic. Therefore, a literature search to assess the current evidence-base for scarring treatment options was conducted, and only those deemed Levels of Evidence 1 or 2 were included. Understanding the spectrum of skin scarring in the first instance is imperative, and is mainly comprised of four distinct endotypes; Stretched (flat), Contracted, Atrophic, and Raised for which the acronym S.C.A.R. may be used. Traditionally, scar assessment and response to therapy has employed the use of subjective scar scales, although these are now being superseded by non-invasive, objective and quantitative measurement devices. Treatment options will vary depending on the specific scar endotype, but fall under one of 3 main categories: (1) Leave alone, (2) Non-invasive, (3) Invasive management. Non-invasive (mostly topical) management of skin scarring remains the most accessible, as many formulations are over-the-counter, and include silicone-based, onion extract-based, and green tea-based, however out of the 52 studies identified, only 28 had statistically significant positive outcomes. Invasive treatment options includes intralesional injections with steroids, 5-FU, PDT, and laser with surgical scar excision as a last resort especially in keloid scar management unless combined with an appropriate adjuvant therapy. In summary, scar management is a rapidly changing field with an unmet need to date for a structured and validated approach.

Advantages and Disadvantages of Using Small and Large Animals in Burn Research: Proceedings of the 2021 Research Special Interest Group

Multiple animal species and approaches have been used for modeling different aspects of burn care, with some strategies considered more appropriate or translatable than others. On April 15, 2021, the Research Special Interest Group of the American Burn Association held a virtual session as part of the agenda for the annual meeting. The session was set up as a pro/con debate on the use of small versus large animals for application to four important aspects of burn pathophysiology: burn healing/conversion; scarring; inhalation injury; and sepsis. For each of these topics, 2 experienced investigators (one each for small and large animal models) described the advantages and disadvantages of using these preclinical models. The use of swine as a large animal model was a common theme due to anatomic similarities with human skin. The exception to this was a well-defined ovine model of inhalation injury; both of these species have larger airways which allow for incorporation of clinical tools such as bronchoscopes. However, these models are expensive and demanding from labor and resource standpoints. Various strategies have been implemented to make the more inexpensive rodent models appropriate for answering specific questions of interest in burns. Moreover, modelling burn-sepsis in large animals has proven difficult. It was agreed that the use of both small and large animal models have merit for answering basic questions about the responses to burn injury. Expert opinion and the ensuing lively conversations are summarized herein, which we hope will help inform experimental design of future research.

Mechanomodulation of Burn Scarring Via Pressure Therapy

Significance: The physical and psychological sequalae of burn injuries account for 10 million disability-adjusted life years lost annually. Hypertrophic scarring (HSc) after burn injury results in reduced mobility, contracture, pain, itching, and aesthetic changes for burn survivors. Despite the prevalence of scarring and the number of scar therapies available, none are highly effective at preventing HSc after burn injury. Recent Advances: Recent studies modulating the mechanical environment surrounding incisional and excisional wounds have shown off-loading of tension to be a powerful strategy to prevent scar formation. Preclinical studies applying force perpendicular to the surface of the skin or using a combination of pressure both circumferentially and perpendicularly have shown substantial reductions in scar thickness and contraction after burn injury. Critical Issues: Though pressure therapy is highly effective in preclinical studies, outcomes in clinical studies have been variable and may be a result of differing therapy protocols and garment material fatigue. A recent adult clinical study reported a significant reduction in pressure after 1 month of use and significant reduction between 1 and 2 months of use, resulting in below therapeutic doses of pressure applied after only 1 month of use. Future Directions: To enhance efficacy of pressure garments, new low-fatigue materials must be developed for use in standard garments or garments must be redesigned to allow for adjustment to compensate for the loss of pressure with time. Additionally, measurements of applied pressure should be performed routinely during clinic visits to ensure that therapeutic doses of pressure are being delivered.

A finite element model of the 3D-printed transparent facemask for applying pressure therapy

BACKGROUND

Transparent facemask has been widely used for the prevention and treatment of facial hypertrophic scars all over the world. 3D printing has improved the fabrication accuracy of the traditional transparent facemasks. However, the pressure distribution pattern generated by the 3D-printed transparent facemasks has not been thoroughly investigated. The aim of this study is to develop a biomechanical model to simulate the pressure distribution of the 3D-printed transparent facemask, and to form the biomechanical basis to guide facemask design.

METHODS

A finite element model comprised of the head bones, the soft tissues of the face and the transparent facemask was established in ABAQUS CAE package. The contact pressure between the facemask and the face was simulated under 7 loading conditions. The calculated results from the model were validated through comparing with the experimental pressure measurements.

FINDINGS

The calculated results from the model well correlated with the experimental pressure measurements (P < 0.05). The biomechanical model is acceptable for the prediction of interface pressure between the facemask and the face.

INTERPRETATION

The pressure distribution pattern showed the facial areas with thin soft tissues and bony prominence experienced concentrated pressure while areas with thick soft tissues received less or no pressure. Suggestions for future facemask design based on the biomechanical model is releasing the areas with concentrated pressure and indenting areas with insufficient pressure.