Pressure Effects on the Growth of Human Scar Fibroblasts:

Strategies to improve facial scars following Mohs micrographic surgery

Mohs micrographic surgery (MMS) is the gold standard treatment for skin cancers of the face, but scarring in these cosmetically sensitive areas remains a challenge, with no clear consensus on the most effective treatments. This study reviews the literature on therapies for specifically facial scars following Mohs surgery, emphasizing their mechanism of action and evidence of efficacy. Non-invasive options such as topical silicone and pressure therapy have shown benefits, while advanced techniques like dermabrasion, microneedling, or energy devices like the pulse-dye, CO2, Erbium, and Nd:YAG lasers, show promise in improving scar pliability and visibility. Intralesional injections of corticosteroids, botulinum toxin, and dermal fillers also have supportive data. Conversely, treatments like topical onion extract and vitamin E lack evidence of efficacy. Managing hypertrophic granulation tissue (HGT) also remains critical to reduce aberrant scarring from second-intention healing (SIH). To ensure optimal clinical outcomes, clinicians should remain updated on the wide range of scar therapies available, focusing on those with established biochemical mechanisms and evidence of efficacy.

Reducing Risks of Facial Scarring

Risk factors for the formation of facial scars include skin type, ethnicity, scar location, and certain medical conditions that contribute to poor or delayed healing. Risk of scar can be reduced with appropriate surgical planning, including proper placement and design of incisions, meticulous skin closure, aseptic technique, and wound care to improve healing. Common pathologic scars include hypertrophic scars and keloid scars, each of which has unique approaches to surgical revision and medical treatment due to their respective risks of recurrence. Topical scar therapies, medical therapies, and surgical revision techniques for improvement in final scar appearance are discussed.

Pressure therapy for scars: Myth or reality? A systematic review

BACKGROUND

Hypertrophic scarring is a deviate occurrence after wound closure and is a common burn sequela. The mainstay of scar treatment consists of a trifold approach: hydration, UV-protection and the use of pressure garments with or without extra paddings or inlays to provide additional pressure. Pressure therapy has been reported to induce a state of hypoxia and to reduce the expression pattern of transforming growth factor-β1 (TGF-β1), therefore limiting the activity of fibroblasts. However, pressure therapy is said to be largely based on empirical evidence and a lot of controversy concerning the effectiveness still prevails. Many variables influencing its effectivity, such as adherence to treatment, wear time, wash frequency, number of available pressure garment sets and amount of pressure remain only partially understood. This systematic review aims to give a complete and comprehensive overview of the currently available clinical evidence of pressure therapy.

METHODS

A systematic search for articles concerning the use of pressure therapy in the treatment and prevention of scars was performed in 3 different databases (Pubmed, Embase, and Cochrane library) according to the PRISMA statement. Only case series, case-control studies, cohort studies, and RCTs were included. The qualitative assessment was done by 2 separate reviewers with the appropriate quality assessment tools.

RESULTS

The search yielded 1458 articles. After deduplication and removal of ineligible records, 1280 records were screened on title and abstract. Full text screening was done for 23 articles and ultimately 17 articles were included. Comparisons between pressure or no pressure, low vs high pressure, short vs long duration and early vs late start of treatment were investigated.

CONCLUSION

There is sufficient evidence that indicates the value of prophylactic and curative use of pressure therapy for scar management. The evidence suggests that pressure therapy is capable of improving scar color, thickness, pain, and scar quality in general. Evidence also recommends commencing pressure therapy prior to 2 months after injury, and using a minimal pressure of 20-25 mmHg. To be effective, treatment duration should be at least 12 months and even preferably up to 18-24 months. These findings were in line with the best evidence statement by Sharp et al. (2016).

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.

Comparison between the portable pressure measuring device and PicoPress® for garment pressure measurement on hypertrophic burn scar during compression therapy

PURPOSE

The current standard treatment for hypertrophic scars following burn injury is pressure garment therapy. The experimenters developed the novel portable pressure measuring device using silicon piezoresistive sensors. As PicoPress® is the most accurate (i.e., lowest variation and error) manometric sensor for pressure measurement, we sought to compare and examine the accuracy of the novel device regarding in vitro pressure measurements at the hypertrophic scar-pressure garment interface.

METHODS

The novel device was designed to operate in non-corrosive media, such as air. The device can use up to six pressure sensing points and was developed to adjust the number of pressure sensors according to the size of the scar. Pressure measurements were acquired through a readout circuit consisting of an analog-to-digital converter, a microprocessor, and a Bluetooth transmission module for wireless data transmission to an external device. All signals were converted into mean pressure expressed in millimeters of mercury (mmHg). The mean pressure values measured by the sensors were compared to those obtained from PicoPress®. 55 garment pressures recordings were obtained from the sensors over this study conducted in 2018-February 2020. We then analyzed the test-retest reliability using the intraclass correlation coefficients (ICC). PicoPress® was also employed in the same pressure garments for obtaining similar measurements. A two way random effects model ICC with 95% confidence intervals was used to compare the mean pressure values obtained from the silicon piezoresistive sensors to the PicoPress® measurements.

RESULTS

The test-retest reliability of the pressure sensors was close to the acceptable level for clinical use regarding stationary interface pressure measurement (ICC = 0.99, 95% CI 0.990-0.997). The mean pressure obtained from the silicon piezoresistive pressure sensors showed an accordance with the measurements from PicoPress® (ICC = 0.97, 95% CI 0.947-0.985).

CONCLUSION

The novel device may present a viable alternative to PicoPress® for garment pressure measurements. In addition, the novel device improves adaptability to the hypertrophic scar shape and size. Complementary characteristics such as wireless transmission to an external device may allow burn patients to continuously wear the device for real-time measurements during pressure garment therapy, thus improving existing devices including PicoPress®.

Clinical effects of transparent facial pressure masks: A literature review

BACKGROUND

Severe facial hypertrophic scars are known to severely impact emotional well-being. Pressure therapy by means of transparent face masks has been used for almost 40 years, but evidence about the clinical effects remains sparse.

OBJECTIVES

To provide a summary on the efficacy of transparent face masks in the treatment of facial hypertrophic scars.

METHODS

A literature search was conducted in PubMed, MEDLINE, and Cochrane databases through 1 January 2018. Articles describing the clinical effects of facial pressure therapy for remodeling the face after trauma or surgery with a validated tool were included. This review included studies of participants treated with facial hypertrophic scars, both minors and adults.

RESULTS

Three articles involving 33 patients were selected for inclusion. Two studies described statistically significant improvement in facial scars measured by durometer, ultrasound, and the Patient and Observer Scar Assessment Scale (POSAS).

CONCLUSIONS

Facial pressure masks have been shown to deliver significant improvement in facial scars, measured by both subjective and objective tools. However, only three studies could be included in this literature review. Also, because of considerable limitations of the studies, it remains difficult to draw substantial conclusions about the efficacy of transparent face masks.

CLINICAL RELEVANCE

This literature review provides a summary of the current evidence on the subjectively and objectively measured clinical effects of transparent face masks in the treatment of facial scars, highlighting the need for further research on this topic.

Manual fabrication of a specialized transparent facial pressure mask: A technical note

BACKGROUND AND AIM

The objective of this study was to describe the manual fabrication of a transparent facial pressure mask for treating facial deformities. The mask combines the use of a silicone inner liner and mechanical pressure in the facial region.

TECHNIQUE

A negative mold is formed by covering the face with plaster. Manipulation of soft tissue is a crucial part in this process. After hardening and removal of the negative mold, the positive mold is formed and dried. Next a rolled silicone sheet is placed over the positive mold in a vacuum environment. Subsequently, the silicones are vulcanized. Then the rigid outside of the mask is created. The silicone inner liner and outside shell are then affixed.

DISCUSSION

This described technique results in accurate facemasks with precise fitting. During therapy, the mask is adjusted multiple times to keep excellent fit, as remodeling of scars and deformities takes place.

CLINICAL RELEVANCE

Facemasks are a reputable therapeutic modality to reduce excessive facial scarring. They require excellent fitting to give pleasing results. To provide a better understanding of facemask therapy, this study describes the manual fabrication technique.

RNA-seq-based analysis of the hypertrophic scarring with and without pressure therapy in a Bama minipig model

Pressure therapy has been proved to be an effective treatment for hypertrophic scars in a clinical setting. However, evidence-based data are controversial and the precise mechanism of action of this technique remains unknown. The aim of this study was to investigate the potential molecular mechanisms of pressure therapy for hypertrophic scars. We established a Bama minipig (Sus scrofa) model of hypertrophic scarring in which the scars were treated with pressure to explore the mechanism of action of the treatment. There were 568 differentially expressed genes (289 upregulated, 279 downregulated) after pressure therapy at 90 days post-injury, whereas only 365 genes were differentially expressed (250 upregulated, 115 downregulated) at 120 days post-injury. These genes were associated with metabolic pathways, ECM-receptor interaction, the PI3K-Akt and MAPK signaling pathways, focal adhesion and cytokine-cytokine receptor interaction. In addition, the qRT-PCR results indicated that the trend of gene expression following pressure therapy was mostly consistent across the two methods. In conclusion, our systematic analysis of the transcriptome has provided a better understanding of the molecular mechanisms involved in pressure therapy and offers an important basis for further studies of the complex signaling pathways regulated by the treatment.

Elastin Is Differentially Regulated by Pressure Therapy in a Porcine Model of Hypertrophic Scar

Beneficial effects of pressure therapy for hypertrophic scars have been reported, but the mechanisms of action are not fully understood. This study evaluated elastin and its contribution to scar pliability. The relationship between changes in Vancouver Scar Scale (VSS) scores of pressure-treated scars and differential regulation of elastin was assessed. Hypertrophic scars were created and assessed weekly using VSS and biopsy procurement. Pressure treatment began on day 70 postinjury. Treated scars were compared with untreated shams. Treatment lasted 2 weeks, through day 84, and scars were assessed weekly through day 126. Transcript and protein levels of elastin were quantified. Pressure treatment resulted in lower VSS scores compared with sham-treated scars. Pliability (VSSP) was a key contributor to this difference. At day 70 pretreatment, VSSP = 2. Without treatment, sham-treated scars became less pliable, while pressure-treated scars became more pliable. The percentage of elastin in scars at day 70 was higher than in uninjured skin. Following treatment, the percentage of elastin increased and continued to increase through day 126. Untreated sham scars did not show a similar increase. Quantification of Verhoeff-Van Gieson staining corroborated the findings and immunofluorescence revealed the alignment of elastin fibers. Pressure treatment results in increased protein level expression of elastin compared with sham-untreated scars. These findings further characterize the extracellular matrix's response to the application of pressure as a scar treatment, which will contribute to the refinement of rehabilitation practices and ultimately improvements in functional and psychosocial outcomes for patients.

A new treatment for reliable functional and esthetic outcome after local facial flap reconstruction: a transparent polycarbonate facial mask with silicone sheeting

BACKGROUND

Facial flap surgery predominantly leads to good functional results. However, in some cases, it can cause unsatisfactory esthetic results. They include persistent erythema, pincushioning, and development of hypertrophic scars. Conservative, reliable treatment for facial flaps is lacking. Pressure and silicone therapy have proven to result in significant improvement in scar erythema, pliability, and thickness in postburn hypertrophic scars. By combining these therapies in a facial mask, the esthetic outcome of facial flaps could be improved. In this retrospective study, the efficacy of a unique transparent face mask containing silicone sheets on the esthetic outcome of postsurgical facial flaps is assessed.

METHODS

Twenty-one patients were assigned to facial pressure mask therapy after they underwent facial flap surgery between July 2012 and September 2015. Patients were treated for a mean duration of 46 weeks. The effects of pressure mask therapy were examined by means of the Patient and Observer Scar Assessment Scale (POSAS).

RESULTS

All POSAS components showed a reduction between start and end of therapy, while itchiness, pigmentation, pliability, thickness, and relief of the flap improved significantly (P < 0.05). Mean total and patient score showed significant reduction between start and end of therapy.

CONCLUSIONS

This study shows that a facial pressure mask layered with silicone results in noticeable flap improvement with a long-lasting result. Level of Evidence: Level III, therapeutic study.

A clinical trial of tension and compression orthoses for Dupuytren contractures

STUDY DESIGN

Randomized clinical trial on 2 patient groups with Dupuytren's disease.

INTRODUCTION

Despite an unpredictable outcome, surgery remains an important treatment for Dupuytren's disease. Orthotic devices are a controversial noninvasive treatment method to influence the myofibroblasts in the nodules.

PURPOSE OF THE STUDY

To detect how much improvement 2 types of orthotic device (tension and compression) as only treatment intervention can provide on a Dupuytren's contracture. Is a compression orthosis better than a tension orthosis?

METHODS

Thirty patients with measurable flexion contractures of the fingers were identified. Both primary and recurrence cases were included. Patients were randomized in 2 groups of 15 patients. One group had a standard tension orthosis (Levame), the other group a newly designed silicon compression orthotic device. Patients were instructed to wear the orthotic devices 20 hours a day during 3 months. Data were collected at first visit and after 3 months of orthotic treatment. Primary outcomes were active extension deficit of each joint and total active extension (TAE) of the digit. Secondary outcome was patient satisfaction. Visual Analog Scale (VAS) score of function and esthetics (0-10 points) were recorded at the start and after 3 months.

RESULTS

Flexion contracture was reduced at least 5 degrees in all patients. After 3 months, TAE was significantly reduced in both groups (both P < .001).The mean change in TAE was 32.36° in the tension group and 46.47° in the compression group. Although reduction of TAE deficit was bigger in the compression group, this difference was not statistically significant (P = .39). VAS scale of esthetics and functionality was significantly increased in both treatment groups. The functional VAS scale after 3 months was 11% higher in the compression group than in the tension group (P = .03). A major complication of a tension orthotic is skin ulcers.

DISCUSSION

Too much tension may cause myofibroblast stimulation and disease progression, whereas continuous limited tension can improve flexion contractures. The idea of a compression device is based on the treatment concept of hypertrophic burn scars.

CONCLUSION

Tension and compression orthotic devices can be used as a nonoperative treatment of Dupuytren's disease in both early proliferative untreated hands and aggressive postsurgery recurrence. Although there is no statistically significant difference, compression orthoses appear to be more effective and are better tolerated. Nevertheless, adjustment of orthotic design and research on long-term results are needed.

LEVEL OF EVIDENCE

I (Randomized controlled trial, Therapeutic study).

Compression therapy affects collagen type balance in hypertrophic scar

BACKGROUND

The effects of pressure on hypertrophic scar are poorly understood. Decreased extracellular matrix deposition is hypothesized to contribute to changes observed after pressure therapy. To examine this further, collagen composition was analyzed in a model of pressure therapy in hypertrophic scar.

MATERIALS AND METHODS

Hypertrophic scars created on red Duroc swine (n = 8) received pressure treatment (pressure device mounting and delivery at 30 mm Hg), sham treatment (device mounting and no delivery), or no treatment for 2 wk. Scars were assessed weekly and biopsied for histology, hydroxyproline quantification, and gene expression analysis. Transcription levels of collagen precursors COL1A2 and COL3A1 were quantified using reverse transcription-polymerase chain reaction. Masson trichrome was used for general collagen quantification, whereas immunofluorescence was used for collagen types I and III specific quantification.

RESULTS

Total collagen quantification using hydroxyproline assay showed a 51.9% decrease after pressure initiation. Masson trichrome staining showed less collagen after 1 (P < 0.03) and 2 wk (P < 0.002) of pressure application compared with sham and untreated scars. Collagen 1A2 and 3A1 transcript decreased by 41.9- and 42.3-fold, respectively, compared with uninjured skin after pressure treatment, whereas a 2.3- and 1.3-fold increase was seen in untreated scars. This decrease was seen in immunofluorescence staining for collagen types I (P < 0.001) and III (P < 0.04) compared with pretreated levels. Pressure-treated scars also had lower levels of collagen I and III after pressure treatment (P < 0.05) compared with sham and untreated scars.

CONCLUSIONS

These results demonstrate the modulation of collagen after pressure therapy and further characterize its role in scar formation and therapy.

A histological study on the effect of pressure therapy on the activities of myofibroblasts and keratinocytes in hypertrophic scar tissues after burn

Although pressure therapy (PT) has been widely used as the first-line treatment for hypertrophic scars (HS), the histopathological changes involved have seldom been studied. This study aimed to examine the longitudinal effect of PT on the histopathological changes in HS. Ten scar samples were selected from six patients with HS after burn and they were given a standardized PT intervention for 3 months while 16 scar samples were obtained on those without PT. The scar biopsies were collected pre-treatment, 1 and 3 months post-intervention for both clinical and histopathological examinations. Clinical assessments demonstrated significant improvement in the thickness and redness of the scars after PT. Histological examination revealed that cell density in the dermal layer was markedly reduced in the 3-months post-pressurized scar tissues, while the arrangement of the collagen fiber was changed from nodular to wave-like pattern. The α-smooth muscle actin immunoreactivity was significantly decreased after 1-month pressure treatment. There was a significant reduction of myofibroblasts population and a concomitant increase in the apoptotic index in the dermal layer in the 3-months' post-pressurized scars. A significant negative correlation was found between the myofibroblasts population and the apoptotic index. The keratinocyte proliferation was found inhibited after PT. Results demonstrated that PT appeared to promote HS maturation by inhibiting the keratinocyte proliferation and suppressing myofibroblasts population, the latter possibly via apoptosis.

Mechanical compression upregulates MMP9 through SMAD3 but not SMAD2 modulation in hypertrophic scar fibroblasts

PURPOSE

Activation of transforming growth factor-β (TGF-β) signaling and matrix metalloproteinases are involved in hypertrophic scar (HS) formation. Compression therapy is known to be an effective approach for the treatment of hypertrophic scarring; however, the underlying molecular mechanisms remain poorly understood. We investigated the relationship between TGF-β signaling activation and matrix metalloproteinases in HS fibroblasts during mechanical compressive stress.

MATERIALS AND METHODS

Two groups of skin tissue from HS and the nearby normal tissue were obtained from surgical patients and analyzed. Primary fibroblasts from the HS tissue and normal fibroblasts were isolated. Pressure therapy was recapitulated in an in vitro three-dimensional culture model, using mechanical stress produced with the Flexcell FX-4000C Compression Plus System. Quantitative real-time PCR (qPCR) was used to analyze the gene expression profiles in skin tissue and cultured primary cells exposed to compressive stress. Knockdown of SMAD2 and SMAD3 was performed using their specific siRNA in HS and normal fibroblasts subjected to compressive stress, and gene expression was examined by qPCR and Western blot.

RESULTS

There was a significant upregulation of the mRNA expression of matrix metalloproteinase-2 (MMP2) and MMP9 in primary HS fibroblasts in response to mechanical stress. In contrast, the mRNA levels of collagen I and collagen III were downregulated in primary HS fibroblasts compared with those in the control cells. SiRNA-mediated knockdown of SMAD3 in the primary fibroblasts exposed to mechanical stress resulted in a decrease in the expression of MMP9 compared to control cells.

CONCLUSION

These results demonstrate that compressive stress upregulates MMP9 by SMAD3 but not by SMAD2.

The effect of pressure and fabrication of pressure therapy gloves on hand sensitivity and dexterity

Pressure therapy gloves always affect the function and performance of hands but the effect is often neglected. In this study, fabrication and reduction factors (RFs) of pressure therapy gloves on hand dexterity and comfort perception are assessed by goniometer, Semmes-Weinstein monofilaments and Purdue Pegboard, as well as through daily activity tasks. A subjective rating scale was also used to record comfort perception. The repeated-measures multivariate analysis of variance and Friedman tests were used to compare hand function tests and comfort sensation results when different glove prototypes were worn in terms of fabrics and RFs. The results show that even though both fabric types and RFs of pressure gloves exert no significant effect on the tactile sensitivity of fingertips, the active range of motion and dexterity of the fingers in carrying out daily tasks and comfort perception are considerably affected. The adoption of a high RF of 20% in making of glove patterns can impact negatively on both hand functions and comfort perception, thus leading to unsatisfactory treatment adherence. Strong associations were found between the comfort performance and fabric properties, including surface roughness, bending rigidity, thermal conductivity and moisture retention. It has been suggested that fabric choice, anticipated fabric tensile behaviour and surface and thermal properties should also be taken into consideration when prescribing pressure therapy glove for treatment of hypertrophic scars.