The effect of probe to skin contact force on Cutometer MPA 580 measurements

A Skin-Inspired High-Performance Tactile Sensor for Accurate Recognition of Object Softness

High-performance tactile sensors with skin-sensing properties are crucial for intelligent perception in next-generation smart devices. However, previous studies have mainly focused on the sensitivity and response range of tactile sensation while neglecting the ability to recognize object softness. Therefore, achieving a precise perception of the softness remains a challenge. Here, we report an integrated tactile sensor consisting of a central hole gradient structure pressure sensor and a planar structure strain sensor. The recognition of softness and tactile perception is achieved through the synergistic effect of pressure sensors that sense the applied pressure and strain sensors that recognize the strain of the target object. The results indicate that the softness evaluation parameter (SC) of the integrated structural tactile sensor increases from 0.14 to 0.47 along with Young's modulus of the object decreasing from 2.74 to 0.45 MPa, demonstrating accurate softness recognition. It also exhibits a high sensitivity of 10.55 kPa-1 and an ultrawide linear range of 0-1000 kPa, showing an excellent tactile sensing capability. Further, an intelligent robotic hand system based on integrated structural tactile sensors was developed, which can identify the softness of soft foam and glass and grasp them accurately, indicating human skin-like sensing and grasping capabilities.

Effects of spironolactone on skin biophysical properties in women with acne treated with oral spironolactone

BACKGROUND

Spironolactone (SPL) is an effective treatment for women acne, but other effects on skin biophysical properties remain to be investigated.

OBJECTIVES

The aim of the current study was to explore the effects of oral SPL used to treat women acne on skin biophysical properties, including hydration, transepidermal water loss (TEWL), skin surface lipid (SSL) levels, mechanical properties, color, pH, and pore size.

MATERIALS AND METHODS

Twenty-five Thai women with acne treated with oral SPL were followed for 6 months. Skin hydration, TEWL, SSL levels, mechanical properties, color, pH, and pore size of the forehead, chest, and inner arm were evaluated at baseline and 2, 4, and 6 months after treatment with oral SPL. Facial and upper back pore size were also assessed. Clinical outcomes were changes in these skin biophysical properties at each visit compared with baseline.

RESULTS

Skin hydration, TEWL, SSL levels, color, pH, and pore size remained stable throughout the study. Facial skin parameters at 6 months demonstrated the following changes: hydration levels, 7.60 (95% confidence interval [CI], -59.74 to 74.94); TEWL, -2.36 (95% CI, -5.77 to 1.06); L* value, 0.51 (95% CI, -0.70 to 1.72); individual typology angle, 1.65 (95% CI -2.27 to 5.57); pH, 0.01 (95% CI -0.43 to 0.46); pore size, -0.24 (95% CI, -1.21 to 0.73); and SSL levels, 7.60 (95% CI -59.74 to 74.94). Improvement of facial mechanical properties was observed. R0 (indicating skin tightness) and R1 (indicating elasticity) showed significant decreases (-0.076 [95% CI, -0.141 to -0.010] and -0.016 [95% CI, -0.033 to -0.001]). R3 and R4 (representing tiring effects) were also improved (-0.091 [95% CI, -0.158 to -0.025] and -0.022 [95% CI, -0.044 to -0.001]). Parameters in the truncal and inner arm areas remained stable, except for skin elasticity and tiring effects, which exhibited a similar trend of improvement as the facial area. The changes were notable as early as 4 months.

CONCLUSION

Oral SPL used for acne did not impair the skin barrier. Moreover, the skin mechanical properties were improved at 4 to 6 months.

Evaluation of breast skin and tissue stiffness using a non-invasive aspiration device and impact of clinical predictors

A personalized 3D breast model could present a real benefit for preoperative discussion with patients, surgical planning, and guidance. Breast tissue biomechanical properties have been poorly studied in vivo, although they are important for breast deformation simulation. The main objective of our study was to determine breast skin thickness and breast skin and adipose/fibroglandular tissue stiffness. The secondary objective was to assess clinical predictors of elasticity and thickness: age, smoking status, body mass index, contraception, pregnancies, breastfeeding, menopausal status, history of radiotherapy or breast surgery. Participants were included at the Montpellier University Breast Surgery Department from March to May 2022. Breast skin thickness was measured by ultrasonography, breast skin and adipose/fibroglandular tissue stiffnesses were determined with a VLASTIC non-invasive aspiration device at three different sites (breast segments I-III). Multivariable linear models were used to assess clinical predictors of elasticity and thickness. In this cohort of 196 women, the mean breast skin and adipose/fibroglandular tissue stiffness values were 39 and 3 kPa, respectively. The mean breast skin thickness was 1.83 mm. Only menopausal status was significantly correlated with breast skin thickness and adipose/fibroglandular tissue stiffness. The next step will be to implement these stiffness and thickness values in a biomechanical breast model and to evaluate its capacity to predict breast tissue deformations.

Characterization of the concentration of agar-based soft tissue mimicking phantoms by impact analysis

In various medical fields, a change of soft tissue stiffness is associated with its physio-pathological evolution. While elastography is extensively employed to assess soft tissue stiffness in vivo, its application requires a complex and expensive technology. The aim of this study is to determine whether an easy-to-use method based on impact analysis can be employed to determine the concentration of agar-based soft tissue mimicking phantoms. Impact analysis was performed on soft tissue mimicking phantoms made of agar gel with a mass concentration ranging from 1% to 5%. An indicator Δt is derived from the temporal variation of the impact force signal between the hammer and a small beam in contact with the sample. The results show a non-linear decrease of Δt as a function of the agar concentration (and thus of the sample stiffness). The value of Δt provides an estimation of the agar concentration with an error of 0.11%. This sensitivity of the impact analysis based method to the agar concentration is of the same order of magnitude than results obtained with elastography techniques. This study opens new paths towards the development of impact analysis for a fast, easy and relatively inexpensive clinical evaluation of soft tissue elastic properties.

Intra- and inter-rater reliabilities of skin mechanical properties measured in healthy individuals using skin elasticity meter

PURPOSE

The aim of this study is to establish a standardized measurement method and to examine the intra- and inter-reliabilities and absolute reliability of measuring skin mechanical properties using a skin elasticity meter (Cutometer®).

METHODS

Ten healthy participated in the study. Skin mechanical properties were measured at four sites: upper arm, lower arm, upper leg and lower leg on both sides in supine position using a non-invasive skin elasticity meter by two trained different raters. The measurements include quantitative indices of the maximal distensibility (R0), elasticity (R2, R5, R7), and viscoelasticity (R6). Intra- and inter- relative reliabilities were determined using the intraclass correlation coefficient (ICC) (1,1) and ICC (2,1) methods, respectively. The absolute reliability was assessed via the Bland-Altman analysis. Moreover, we evaluated the minimal detectable change at a 95% confidence level (MDC95).

RESULTS

At each site, the ICC (1,1) values were >0.90, and the ICC (2,1) values were >0.50. The Bland-Altman analysis did not reveal any fixed errors, and several sites and parameters have proportional errors.

CONCLUSIONS

In this study, intra- and inter-reliabilities were measured at "excellent" and more than "moderate" levels, respectively. However, because some proportional errors were observed, the limits of reliability agreement should be considered when using the proposed methods. We believe that the results of this study can be applied to clinical research in field of rehabilitation treatment.

A randomized, double-blind, controlled study evaluating the effects of two facial serums on skin aging

BACKGROUND

Skin aging is a natural process that occurs because of oxidative stress. Facial skin aging is often concerning for individuals due to the exposure of the face.

OBJECTIVES

To assess and compare the effects of two anti-aging facial serums on the following characteristics associated with facial skin aging: fine lines/wrinkles, age spots, firmness, elasticity, texture, radiance, tone, lifting, clarity, and complexion.

METHODS

A 24-week, double-blind controlled study was conducted on 130 participants who were randomized into two groups: facial serum with Liposomal Blend and facial serum without Liposomal Blend. Clinical evaluations (Visual Analog Scale) and instrumental evaluations (Cutometer, SIAscope, and Clarity Pro image analysis) were performed at weeks 0 (baseline), 2, 4, 8, 12, and 24 to assess for changes in skin aging characteristics.

RESULTS

A total of 123 participants completed the study; participants that used the facial serum with Liposomal Blend had significantly greater improvements in skin aging characteristics compared to those that used the facial serum without Liposomal Blend. This study shows that Liposomal Blend is a vehicle with the ability to enhance the anti-aging properties of the ingredients within the facial serum by facilitating its delivery into the underlying layers of the skin. Higher concentration of ingredients at the site of action could potentially lead to greater damage repair and improvements in signs of facial skin aging.

CONCLUSION

By using Liposomal Blend, practitioners and pharmacists could potentially improve the delivery of the ingredients within their formulations into the skin, which may lead to increased treatment efficacy.

Fat infiltration into dermal layer induces aged facial appearance by decreasing dermal elasticity

BACKGROUND

Facial morphology changes with aging, producing an aged appearance, but the mechanisms involved are not fully established. We recently showed that subcutaneous fat infiltrates into the dermal layer with aging, but it is not yet clear whether and how this drastic change of the dermal layer influences facial appearance.

PURPOSE

We aimed to establish the role of fat infiltration in producing an aged facial appearance and to clarify the mechanism involved.

METHODS

We analyzed the severity of fat infiltration in cheek skin of 30 middle-aged female volunteers by means of ultrasonography. Severity of the nasolabial fold, an established age-related morphology, was evaluated based on our photographic grading criteria as a measure of aged appearance. Skin elasticity was measured with a Cutometer.

RESULTS

Fat infiltration to the dermal layer was detected at the cheek skin noninvasively by means of ultrasonography. Fat infiltration severity, measured as the minimum depth of the fat inside the dermal layer from the skin surface, was positively correlated with the magnitude of the nasolabial fold. Further, fat infiltration severity was significantly negatively correlated with dermal elasticity.

CONCLUSIONS

Our results suggest that fat infiltration into the dermal layer is a critical factor inducing aged appearance of the face. The infiltrated fat decreases the dermal elasticity, which exacerbates nasolabial folds, namely producing an aged facial appearance.

Objective Burn Scar Assessment in Clinical Practice Using the Cutometer©: Introduction and Validation of a Standardized Measurement Protocol

An objective burn scar assessment is essential to informed therapeutic decision-making and to monitor scar development over time. However, widely employed scar rating scales show poor inter-rater reliability. For this study we developed a standardized measurement protocol for the Cutometer© applicable for objective burn scar assessment in everyday clinical practice. We developed a measurement protocol for the Cutometer© MPA 580 including a scar site relocation technique based on anatomical landmarks. The protocol emerged through several steps: Identifying key factors for valid and reliable measurements, preliminary testing, specification of technical details, refining the protocol and final testing. Consecutively, the protocol was validated for inter-rater reliability by assessing 34 burn scars in 17 patients by four clinicians and computing an Intra-class Correlation Coefficient (ICC). Parameter R0, representing scar pliability, was identified as the best suited output parameter yielding excellent inter-rater reliability for average measures (ICC 0.92 [95% CI 0.86; 0.96]) and acceptable reliability for single measures (ICC: 0.74 [0.61; 0.84]). The pressure applied on the measuring probe was identified as an influential confounding factor for reliable measurements. Rater gender did not influence reliability of measurements. The introduced standardized measurement protocol for the Cutometer© MPA 580 enables an objective and reliable burn scar assessment for clinical as well as research purposes.

Standardizing Dimensionless Cutometer Parameters to Determine In Vivo Elasticity of Human Skin

Objective: Skin fibrosis places an enormous burden on patients and society, but disagreement exists over methods to quantify severity of skin scarring. A suction cutometer measures skin elasticity in vivo, but it has not been widely adopted because of inconsistency in data produced. We investigated variability of several dimensionless parameters generated by the cutometer to improve their precision and accuracy. Approach: Twenty adult human subjects underwent suction cutometer measurement of normal skin (NS) and fibrotic scars (FS). Using Mode 1, each subject underwent five trials with each trial containing four curves. R0/2/5/6/7 and Q1/2/3 data were collected. Analyses were performed on these calculated parameters. Results: R0/2/5/6/7 and Q1/2 parameters from curves 1 to 4 demonstrated significant differences, whereas these same parameters were not significantly different when only using curves 2-4. Individual analysis of all parameters between curve 1 and every subsequent curve was statistically significant for R0, R2, R5, R6, R7, Q1, and Q2. No differences were appreciated for parameter Q3. Comparison between NS and FS were significantly different for parameters R5, Q1, and Q3. Innovation: Our study is the first demonstration of accurate comparison between NS and FS using the dimensionless parameters of a suction cutometer. Conclusions: Measured parameters from the first curve of each trial were significantly different from subsequent curves for both NS and FS. Precision and reproducibility of data from dimensionless parameters can therefore be improved by removing the first curve. R5, Q1, and Q3 parameters differentiated NS as more elastic than FS.

Palmar skin elasticity measured by the Cutometer MPA 580 is decreased in mild Dupuytren's disease compared to healthy controls

Introduction

Involvement of the palmar skin is often seen in patients with Dupuytren's disease (DD) with severe finger contractures. However, skin elasticity may be already decreased earlier in the disease. The Cutometer MPA 580 could provide an objective skin measurement tool to assess this decrease in elasticity. Linking objective skin measurements to functional outcome measures could lead to better prediction of disease progression. We set up a study to investigate if the Cutometer was able to detect differences in skin elasticity between patients with mild Dupuytren's disease and healthy controls.

Methods

A cross-sectional analytical study was performed. Three assessors measured skin elasticity (palmar hand) on two sites using the Cutometer on 30 patients with mild DD and 30 healthy controls. Student's t-test was used to evaluate differences in skin elasticity and a linear model to evaluate interactions between the groups and sites.

Results

Significant differences in skin elasticity were found between DD patients and controls, as well as differences based on the location examined.

Discussion

Similar to other skin conditions, the Cutometer MPA 580 was able to demonstrate a significant lower elasticity in the palmar skin in DD patients compared to healthy controls. A decrease in skin elasticity in different locations of the hand correlated with areas that often pose problems in the treatment of more severe DD. The Cutometer could potentially be a tool to identify these areas earlier in the disease.

Can the CutiScan CS 100® measure anisotropy and viscoelasticity in scar tissue after mastectomy? A reliability and validity study

BACKGROUND

Scars have different biomechanical characteristics, including anisotropy and viscoelasticity compared to healthy skin. To assess these characteristics, the CutiScan CS 100^® can be used. The aim of the present study is to investigate reliability and validity of this device in breast cancer patients.

MATERIALS AND METHODS

Thirty female patients, with scar adhesions following mastectomy were assessed with the CutiScan CS 100^® . Maximal distensibility (pixels) (V1), after-suction return rate (pixels) (V2), and their ratio (%) (V3) at three points on and around the scar were assessed as measures of viscoelasticity. For intra- and interrater reliabilities, the intra-class correlation coefficient (ICC) and its 95% confidence intervals were calculated. The standard error of measurement (SEM) was calculated to interpret reproducibility of these measurements. To investigate criterion validity of the measurement of anisotropy, measurements in the direction of healthy skin were compared with measurements in the direction of the scar, using a paired t-test.

RESULTS

V1, V2, and V3 show poor to moderate intrarater reliability (ICC 0.00-0.72) and interrater reliability (ICC 0.00-0.53). The maximum displacement (V1) on the measurement point above the scar shows the best reliability (ICC 0.33-0.72). The SEM is about the same for all parameters at all three points. The paired sample t-test showed a significant difference (p < 0.05) between V1 in the direction towards the scar versus the measurement towards healthy tissue, on the point below the scar.

CONCLUSION

These first reliability and validity results of the CutiScan CS 100^® for measuring anisotropy and viscoelasticity in scar tissue adhesions after mastectomy seem promising. Further research is needed addressing the limitations of the present study design.

Longitudinal monitoring and prediction of long-term outcome of scar stiffness on pediatric patients

Background

Hypertrophic scarring after burn injury is one of the greatest unmet challenges in patients with burn injuries. A better understanding of the characteristics of scar maturation and early prediction of the long-term outcome of scarring are prerequisites for improving targeted therapies and pivotal for patient counselling.

Methods

Repeated measurements of scar stiffness in 11 pediatric patients were performed over the course of 1 year using 2 suction devices, the Cutometer and the Nimble. In addition, the observer pliability score of the Patient and Observer Scar Assessment Scale was applied. This longitudinal study allowed quantification of the ability of each of the measured parameters to reflect scar maturation, as indicated by change in skin pliability/stiffness, over time (using linear regression); the ability to distinguish individual patients (intraclass correlation coefficient (ICC)); the correlation of the devices (Spearman correlation coefficient); and the ability to predict long-term scar maturation based on early scar assessment (using receiver operating characteristic).

Results

All the tools used showed significant longitudinal decrease of scar stiffness from 3 months until 12 months after the injury. The Nimble (ICC_patient ^Nimble = 0.99) and the Cutometer (ICC_patient ^Cuto = 0.97) demonstrated an excellent ability to distinguish between individual patients. The Nimble seemed to be able to predict the 12-month pliability of scars based on early (3-month) measurements (area under the curve (AUC)_12m ^POSAS = 0.67; AUC_12m ^C = 0.46; AUC_12m ^N = 0.79).

Conclusions

The results of this preliminary study suggest that all 3 tools provide suitable means to quantify alterations in scar stiffness over time. Initial evidence suggests the Nimble is most favorable for predicting changes in stiffness associated with long-term scar maturation. Further studies with a larger sample size are required to validate tissue suction as a clinical tool for analysis of changes of scar stiffness over time.

On the Reliability of Suction Measurements for Skin Characterization

in vivo skin characterization methods were shown to be useful in the detection of microstructural alterations of the dermis due to skin diseases. Specifically, the diagnostic potential of skin suction has been widely explored, yet measurement uncertainties prevented so far its application in clinical assessment. In this work, we analyze specific factors influencing the reliability of suction measurements. We recently proposed a novel suction device, called Nimble, addressing the limitations of existing instruments, and applied it in clinical trials quantifying mechanical differences between healthy skin and scars. Measurements were performed with the commercial device Cutometer and with the new device. A set of new suction measurements was carried out on scar tissue and healthy skin, and FE-based inverse analysis was applied to determine corresponding parameters of a hyperelastic-viscoelastic material model. FE simulations were used to rationalize differences between suction protocols and to analyze specific factors influencing the measurement procedure. Tissue stiffness obtained from Cutometer measurements was significantly higher compared to the one from Nimble measurements, which was shown to be associated with the higher deformation levels in the Cutometer and the nonlinear mechanical response of skin. The effect of the contact force exerted on skin during suction measurements was quantified, along with an analysis of the effectiveness of a corresponding correction procedure. Parametric studies demonstrated the inherently higher sensitivity of displacement- over load-controlled suction measurements, thus rationalizing the superior ability of the Nimble to distinguish between tissues.

Purple tulip extract improves signs of skin aging through dermal structural modulation as shown by genomic, protein expression and skin appearance of volunteers studied

BACKGROUND

Purple tulip extract is a rich source of flavonoids which are powerful antioxidants and can hence be considered as an ideal candidate for use in skin care products.

AIMS

We aimed to evaluate the effects of purple tulip extract on skin quality and to determine its molecular modes of interaction.

METHODS

A pangenomic study on human skin fibroblasts was carried out to analyze multiple changes in gene expression. Ex vivo studies of human skin explants exposed to ultraviolet (UV) irradiation or H₂ O₂ were performed to assess modulations of protein expression. Finally, a clinical assay was carried out to evaluate the efficacy of purple tulip extract on skin appearance and condition of aged women.

RESULTS

Genetic modulation analyses led us to infer the induction of many biological functions including cell differentiation, proliferation, migration, inflammatory responses, and matrix remodeling. The ex vivo studies revealed an enhancement of the collagen network and increased expression of glycosaminoglycans (GAG), fibronectin, and collagen VI. Finally, the clinical study highlighted the potential anti-aging properties of the purple tulip extract which decreased the relaxation of the oval face and improved skin elasticity after 28 days of treatment. Significant reductions of the length and depth of the nasolabial wrinkles were also observed.

CONCLUSION

Our genomics data on the effect of purple tulip extract on the ex vivo UV-challenged skin showed that genes responsible for, among others, the upkeep of the skin, such as collagen induction, immune cell proliferation, and epidermal repair, were all up-regulated. More importantly, the clinical study corroborated these data by the visible and measurable effects of the topical purple tulip extract on the aged skin of 22 women, further demonstrating the beneficial impact of the extract on aged skin.

A blackberry-dill extract combination synergistically increases skin elasticity

BACKGROUND

The loss of structural elastin due to intrinsic and extrinsic ageing results in the skin's inability to stretch and recoil (decrease in elasticity) and manifests as loss of skin firmness and sagging. While other extracellular matrix (ECM) components such as collagen and hyaluronic acid are continually synthesized and assembled through life, elastic fibres are not. Elastic fibre assembly and functionality require fibre cross-linking, induced by the lysyl oxidase-like (LOXL) enzymes, which sharply decrease during ageing.

OBJECTIVE

To evaluate the enhanced elastogenic effect of a blackberry-dill extract combination, which was hypothesized to induce elastin fibre component synthesis, fibre cross-linking and reduce elastin fibre degradation.

METHODS

The blackberry and the dill extracts were tested separately and in combination to confirm single ingredient bioactivity and synergistic benefits. Human skin explants, dermal fibroblasts, elastase assays, ELISAs, quantitative real-time PCRs and spectrofluorometer measurements were used. Moreover, a double-blinded, placebo-controlled clinical study was carried out to assess skin elasticity using Cutometer and histologically from biopsies.

RESULTS

The blackberry extract induced elastin gene expression, elastin promoter activity and inhibited elastic fibre degradation by matrix metalloproteinases (MMPs) 9 and 12. The dill extract induced elastin, collagen and LOXL1 gene expression, resulting in enhanced fibre cross-linking in human skin explants. Clinically, the blackberry and dill combination treatment displayed synergistic pro-elasticity activity as compared to each ingredient alone and placebo.

CONCLUSION

Taken together, these results demonstrated the two multimodal plant-based extracts complemented each other in terms of bioactivity and resulted in a synergistic elastogenesis induction.

Validation of the suction device Nimble for the assessment of skin fibrosis in systemic sclerosis

Objectives

Skin fibrosis is a main hallmark of systemic sclerosis (SSc). Clinical assessment is done semi-quantitatively using the modified Rodnan skin score (mRSS). Objective measurements for quantifying skin fibrosis could complement the mRSS to achieve higher reproducibility. The aim of this study was to explore the potential of suction measurements to detect structural changes in the skin that are associated with skin fibrosis.

Methods

This clinical trial included 30 SSc patients and 30 healthy volunteers (HC). We validated a novel suction device—the Nimble—to quantify skin stiffness in comparison to the Cutometer using the OMERACT filter.

Results

A significant difference (p < 0.05) between the skin stiffness of HC and SSc patient groups was found for each location measured. The correlation between the measurements of forearm skin stiffness and the mRSS values was high for the Nimble (r = 0.82) and moderate for the Cutometer (r = 0.58). A ROC analysis showed good ability for the Nimble to distinguish between SSc patients with and without skin involvement (AUC = 0.82). Both suction devices provided excellent reliability in all measurements on HC and SSc patients and proved face validity and feasibility.

Conclusion

Suction devices assessing skin stiffness, such as the Nimble, show clear potential to objectively quantify skin fibrosis in SSc patients and might be promising outcome measures complementing established methods such as the mRSS.

Trial registration

Clinicaltrials.gov, NCT03644225, Registered 23 August 2018—Retrospectively registered, http://www.clinicaltrials.gov

A bioinspired stretchable membrane-based compliance sensor

Compliance sensation is a unique feature of the human skin that electronic devices could not mimic via compact and thin form-factor devices. Due to the complex nature of the sensing mechanism, up to now, only high-precision or bulky handheld devices have been used to measure compliance of materials. This also prevents the development of electronic skin that is fully capable of mimicking human skin. Here, we developed a thin sensor that consists of a strain sensor coupled to a pressure sensor and is capable of identifying compliance of touched materials. The sensor can be easily integrated into robotic systems due to its small form factor. Results showed that the sensor is capable of classifying compliance of materials with high sensitivity allowing materials with various compliance to be identified. We integrated the sensor to a robotic finger to demonstrate the capability of the sensor for robotics. Further, the arrayed sensor configuration allows a compliance mapping which can enable humanlike sensations to robotic systems when grasping objects composed of multiple materials of varying compliance. These highly tunable sensors enable robotic systems to handle more advanced and complicated tasks such as classifying touched materials.

Assessment of Pliability and Elasticity of the External Nasal Skin in Patients With Unilateral Nasal Valve Collapse: A Static Biomechanical Evaluation

Importance

Understanding the skin biomechanics, specifically pliability and elasticity, in patients with nasal valve collapse may allow for new methods to assess which patients require more advanced nasal valve surgery.

Objective

To test the hypothesis that in patients with unilateral nasal valve collapse, the side of the nose with the collapse will have lower elasticity and increased pliability compared with the normal side, as assessed by a blinded observer using the Cutometer MPA 580.

Design, Setting, and Participants

Prospective, investigator-blinded, case-control cohort study of patients with unilateral nasal valve collapse and subjective nasal obstruction conducted in an academic otolaryngology-head and neck surgery clinic.

Interventions

Patients were assessed using the Cutometer MPA 580 by a blinded assessor. Three measurements were performed bilaterally on the exterior skin of the nose corresponding to the level of the inferior edge of the upper lateral cartilage. Measurements taken at the skin inferior to the zygoma were used as a control.

Main Outcomes and Measures

Primary outcome measures of the nasal skin were pliability (Uf, defined as the lengthening of the skin after 3 seconds of constant load) and elasticity (Ua/Uf, defined as the percentage of the skin that returned to its normal position 3 seconds after the release from the 3-second constant load).

Results

Of the 27 patients included in the study, 15 (56%) were male, and 12 (44%) were female; mean (SD) age, 44 (21) years (range, 16-90 years). There was no difference between the measurements of the skin overlying the area of nasal valve collapse in elasticity: side without collapse (0.960% [0.031%]) vs side with collapse (0.967% [0.036%]) (mean difference, 0.007%; 95% CI, -0.018% to 0.021%) (P = .90). However, there was a significant difference in pliability: side of the nose without collapse (0.520 [0.139] mm) vs side with collapse (0.610 [0.200]) (mean difference, 0.090 mm; 95% CI, 0.014-0.156 mm) (P = .02).

Conclusions and Relevance

Although the skin in patients with nasal valve collapse appears to maintain its elasticity, it demonstrates an increased ability to stretch and lengthen compared with nasal skin of those without valve collapse. Future studies are required to determine whether the biomechanical changes are related to the length and severity of nasal obstruction, or whether these changes in the skin may help predict who will benefit from nasal valve surgery and whether these patients are at an increased risk of surgical failure.

Level of Evidence

2.

Investigating the intra- and inter-rater reliability of a panel of subjective and objective burn scar measurement tools

BACKGROUND

Research into the treatment of hypertrophic burn scar is hampered by the variability and subjectivity of existing outcome measures. This study aims to measure the inter- and intra-rater reliability of a panel of subjective and objective burn scar measurement tools.

METHODS

Three independent assessors evaluated 55 scar and normal skin sites using subjective (modified Vancouver Scar Scale [mVSS] & Patient and Observer Scar Assessment Scale [POSAS]) and objective tools. The intra-class correlation coefficient was utilised to measure reliability (acceptable when >0.70). Patient satisfaction with the different tools and scar parameter importance were assessed via questionnaires.

RESULTS

The inter-rater reliabilities of the mVSS and POSAS were below the acceptable limit. For erythema and pigmentation, all of the Scanoskin and DSM II measures (except the b* value) had acceptable to excellent intra and inter-rater reliability. The Dermascan ultrasound (dermal thickness, intensity) had excellent intra- and inter-rater reliability (>0.90). The Cutometer R0 (firmness) had acceptable reliability but not R2 (gross elasticity). All objective measurement tools had good overall satisfaction scores. Patients rated scar related pain and itch as more important compared to appearance although this finding was not sustained when corrected for multiple comparisons.

CONCLUSION

The objective scar measures demonstrated acceptable to excellent intra- and inter-rater reliability and performed better than the subjective scar scales.

Effects of red ginseng on the elastic properties of human skin

Background

Red ginseng contains components, including microelements, vitamins, essential oils, and fatty acids, that can be used in skincare to delay the aging process. We investigated the effects of red ginseng treatment on skin elasticity by assessing cellular stiffness and measuring collagen protein synthesis.

Methods

Human dermal fibroblasts were treated with red ginseng, and the resulting changes in stiffness were investigated using atomic force microscopy. Cytoskeletal changes and mRNA expression of biomarkers of aging, including that of procollagens I and VII, elastin, and fibrillin-1, were investigated. Collagen in a human skin equivalent treated with red ginseng was visualized via hematoxylin and eosin staining, scanning electron microscopy, and atomic force microscopy.

Results and conclusion

The stiffness of fibroblasts was significantly reduced by treatment with red ginseng concentrations of ≥ 0.8 mg/mL. The ratio of F-actin to G-actin decreased after treatment, which corresponded to a change in fibroblast stiffness. The storage modulus (G′) and loss modulus (G″) of the skin equivalent were both lowered by red ginseng treatment. This result indicates that the viscoelasticity of the skin equivalent can be restored by red ginseng treatment.

Biopharmaceutical Development of a Bifonazole Multiple Emulsion for Enhanced Epidermal Delivery

Efficient topical delivery of imidazolic antifungals faces the challenge of overcoming its limited water solubility and its required long-lasting duration of treatments. In this paper, a hydrophilic multiple emulsion (ME) of Bifonazole (BFZ) is shown to maximize its skin retention, minimize its skin permeation, and maintain an acceptable level of being harmless in vivo. The formulations were pharmaceutically characterized and application properties were assessed based on viscosity measurements. Non-Newtonian pseudoplastic shear thinning with apparent thixotropy was observed, facilitating the formulation retention over the skin. The in vitro release profile with vertical diffusion cells showed a predominant square-root release kinetic suggesting an infinite dose depletion from the formulation. Ex vivo human skin permeation and penetration was additionally evaluated. Respective skin permeation was lower than values obtained with a commercial O/W formulation. The combination of amphoteric and non-ionic surfactants increased the bifonazole epidermal accumulation by a factor of twenty. This fact makes the possibility of increasing its current 24 h administration frequency more likely. Eventual alterations of skin integrity caused by the formulations were examined with epidermal histological analysis and in vivo preclinical measurements of skin elasticity and water retrograde permeation. Histological analysis demonstrated that the multiple emulsions were harmless. Additionally, modifications of in vivo skin integrity descriptors were considered as negligible.

A novel ultra-light suction device for mechanical characterization of skin

Suction experiments have been extensively applied for skin characterization. In these tests the deformation behavior of superficial tissue layers determines the elevation of the skin surface observed when a predefined negative (suction) pressure history is applied. The ability of such measurements to differentiate between skin conditions is limited by the variability of the elevation response observed in repeated experiments. The scatter was shown to be associated with the force exerted by the observer when holding the instrument against the skin. We have developed a novel suction device and a measurement procedure aiming at a tighter control of mechanical boundary conditions during the experiments. The new device weighs only 3.5 g and thus allows to minimize the force applied on the skin during the test. In this way, it is possible to reliably characterize the mechanical response of skin, also in case of low values of suction pressure and deformation. The influence of the contact force is analyzed through experiments on skin and synthetic materials, and rationalized based on corresponding finite element calculations. A comparative study, involving measurements on four body locations in two subjects by three observers, showed the good performance of the new procedure, specific advantages, and limitations with respect to the Cutometer^®, i.e. the suction device most widely applied for skin characterization. As a byproduct of the present investigation, a correction procedure is proposed for the Cutometer measurements, which allows to partially compensate for the influence of the contact force. The characteristics of the new suction method are discussed in view of future applications for diagnostic purposes.

Organization of the dermal matrix impacts the biomechanical properties of skin

BACKGROUND

Human skin has the crucial roles of maintaining homeostasis and protecting against the external environment. Skin offers protection against mechanical trauma due to the reversible deformation of its structure; these biomechanical properties are amenable to dynamic testing using noninvasive devices.

OBJECTIVES

To characterize the biomechanical properties of young, black African/African-Caribbean and white Northern European skin from different anatomical sites, and to relate underlying skin architecture to biomechanical function.

METHODS

Using cutometry and ballistometry, the biomechanical properties of buttock and dorsal forearm skin were determined in black African/African-Caribbean (n = 18) and white Northern European (n = 20) individuals aged 18-30 years. Skin biopsies were obtained from a subset of the volunteers (black African/African-Caribbean, n = 5; white Northern European, n = 6) and processed for histological and immunohistochemical detection of the major elastic fibre components and fibrillar collagens.

RESULTS

We have determined that healthy skin from young African and white Northern European individuals has similar biomechanical properties (F3): the skin is resilient (capable of returning to its original position following deformation, R1), exhibits minimal fatigue (R4) and is highly elastic (R2, R5 and R7). At the histological level, skin with these biomechanical properties is imbued with strong interdigitation of the rete ridges at the dermoepidermal junction (DEJ) and candelabra-like arrays of elastic fibres throughout the papillary dermis. Dramatic disruption to this highly organized arrangement of elastic fibres, effacement of the rete ridges and alterations to the alignment of the fibrillar collagens is apparent in the white Northern European forearm and coincides with a marked decline in biomechanical function.

CONCLUSIONS

Maintenance of skin architecture - both epidermal morphology and elastic fibre arrangement - is essential for optimal skin biomechanical properties. Disruption to underlying skin architecture, as observed in the young white Northern European forearm, compromises biomechanical function.

Influence of therapeutic ultrasound on the biomechanical characteristics of the skin

BACKGROUND

Skin function is dependent on its biomechanical characteristics, resistance, malleability, and elasticity. Therapeutic ultrasound may increase cutaneous malleability thus and optimize the rehabilitation process on specific diseases. The aim of this study is to evaluate possible alterations of biomechanical characteristics of the normal skin after therapeutic ultrasound application.

METHODS

Thirty-one volunteers took part of the study, and the average age was 31.61 ± 8.37 years old. Biomechanical characteristics evaluation of the skin was performed with the Cutometer MPA 580 (Courage + Khazaka Electronic-Köln, Germany) of 2-mm probe hole and 500-mbar vacuum. Skin characteristics were analyzed before and after therapeutic ultrasound application, and the variables R0 (distensibility), R2 (gross elasticity), and R6 (viscoelasticity) were used for the study. Areas of therapeutic ultrasound application (continuous, 3 MHz, 1 W/cm(2) SATA) were defined at the upper limbs and standardized using a neoprene template. Sociodemographic data of volunteers were analyzed using SPSS 15.0. To analyze the distribution of the data, the Shapiro-Wilk test was used, which showed the normal distribution for R0 values, R2 and R6. For this procedure, the PROC TTEST from SAS® 9.0 software and Minitab 16 software, with significance, was set at the 0.05 level.

RESULTS

In relation to R0, a significant increase (p = 0.001) was observed for the distensibility, when compared to values of pre- (0.3273 mm) and immediately post- (0.3795 mm) resource application which feature a greater distensibility. Related to R2 values, a significant increase (p = .001) of the gross elasticity at pre- (0.8419) and post- (0.8884) therapeutic ultrasound application was found.

CONCLUSIONS

Therapeutic ultrasound promotes significant alterations of the biomechanical characteristics of the skin.

TRIAL REGISTRATION

ClinicalTrials.gov, 1111-1146-7342.

[Benefits of using the cutometer to evaluate the effectiveness of skin treatments in plastic and maxillofacial surgery]

INTRODUCTION

Evaluating skin properties is often too subjective. Using the cutometer allows one to take objective measures of certain mechanic properties of the skin such as visco-elasticity. The aim of this article is to evaluate through a review of existing literature the advantages and the limits of the cutometer and to propose an improvement.

MATERIAL AND METHODS

The selection of articles has been conducted with the PubMed database in order to identify all publications concerning the cutometer up until September 2013. The analysis criteria were: (1) quantitative distribution of articles from the first publication until today; (2) qualitative distribution over the various medical fields. The articles have been organized in 3 groups: medical, surgical and burns; (3) list of biases in the interpretation of results and limits of this measuring tool.

RESULTS

One hundred and twenty-nine publications have been included. The first article regarding the cutometer was published in 1994. We observe an increase in the number of publications after 2005. Most of the articles were published in medical journals of dermatology or cosmetology (83%), only 9% of articles have been published in burn study journals and 8% in surgical journals. The pressure applied by the experimenter constitutes the main measure bias.

DISCUSSION

The use of an external device maintaining the probe with an invariable pressure corresponding to its own weight enables more reliable results all the while limiting the inter- and intra-individual variability.

The effect of probe placement on inter-trial variability when using the Cutometer MPA 580

There is limited data independently assessing the optimal use of the Cutometer MPA580. The purpose of this study is to test the hypothesis that the assessment of elastic recoil is significantly different when utilizing two different probe placement protocols. In protocol A, four trials were performed, in which the probe was removed from the skin between trials. In protocol B, the probe was not removed from the skin between trials. Fifty-four patients were enrolled and all completed the testing. When assessing elasticity (Ua/Uf), the inter-class correlation was 0.83 for protocol A and 0.48 for protocol B (p <0.001). There was no significant difference between individual trials for protocol A. Trial one of protocol B was significantly different (p < 0.001) than trials 2-4 for protocol B. Trial one of protocol B was not significantly different than any trial in protocol A. The results of this study suggest that the method in which a clinician performs repeated measure testing has a significant effect on the outcome measures when using the Cutometer. Removing the probe between trials appears to result in measures with higher reliability.

The effect of topically applied tissue expanders on radial forearm skin pliability: a prospective self-controlled study

BACKGROUND

The use of pre-operatively applied topical tissue expansion tapes have previously demonstrated increased rates of primary closure of radial forearm free flap donor sites. This is associated with a reduced cost of care as well as improved cosmetic appearance of the donor site. Unfortunately, little is known about the biomechanical changes these tapes cause in the forearm skin. This study tested the hypothesis that the use of topically applied tissue expansion tapes will result in an increase in forearm skin pliability in patients undergoing radial forearm free flap surgery.

METHODS

Twenty-four patients scheduled for head and neck surgery requiring a radial forearm free flap were enrolled in this prospective self-controlled observational study. DynaClose tissue expansion tapes (registered Canica Design Inc, Almonte, Canada) were applied across the forearm one week pre-operatively. Immediately prior to surgery, the skin pliability of the dorsal and volar forearm sites were measured with the Cutometer MPA 580 (registered Courage-Khazaka Electronic GmbH, Cologne, Germany) on both the treatment and contralateral (control) arms. Paired t-tests were used to compare treatment to control at both sites, with p < 0.025 defined as statistically significant.

RESULTS

There was a statistically significant increase in pliability by a mean of 0.05 mm (SD = 0.09 mm) between treatment and control arms on the dorsal site (95% CI [0.01, 0.08], p = 0.018). This corresponded to an 8% increase in pliability. In contrast, the volar site did not show a statistically significant difference between treatment and control (mean difference = 0.04 mm, SD = 0.20 mm, 95% CI [-0.04, 0.12], p = 0.30).

CONCLUSIONS

This result provides evidence that the pre-operative application of topical tissue expansion tapes produces measurable changes in skin biomechanical properties. The location of this change on the dorsal forearm is consistent with the method of tape application. While this increase in skin pliability may account for the improved rate of primary donor site closure reported using this technique, the results did not reach our definition of clinical significance.

Skin Biomechanical Changes after Injection of Onabotulinum Toxin A: Prospective Assessment of Elasticity and Pliability

OBJECTIVE

This study aimed to test the hypothesis that the administration of onabotulinum toxin A will result in an increase in skin pliability and elasticity.

STUDY DESIGN

A prospective case series with planned data collection in which patients were treated with onabotulinum toxin and assessed at baseline, 2 weeks post-injection, and 2 months post-injection.

SETTING

A private cosmetic surgery clinic associated with a tertiary academic hospital.

SUBJECTS AND METHODS

Forty women were prospectively enrolled to receive onabotulinum toxin A into their glabella, forehead, and lateral orbit. Outcomes were assessed at baseline, 2 weeks posttreatment, and 2 months posttreatment using the Cutometer MPA 580. Skin pliability (Uf) and the elastic recoil (Ua/Uf) were recorded as the 2 primary outcome measures.

RESULTS

There was a significant effect of onabotulinum toxin on skin elasticity (f = 47.8, P = .001) with a mean (+/- SE) increase in elastic recoil of 20% (4.4%) for the glabellar region (P < .001) and 18% (4.0%) for the lateral orbit (P < .0001). There was a significant effect of the treatment on skin pliability (f = 46.9, P < .001) with a mean (+/- SE) increase of 26% (5.4%) for the lateral orbit (P = .001) and 52% (8.3%) for the glabellar region (P < .001).

CONCLUSION

Injection of onabotulinum toxin into the lateral orbital, forehead, and glabellar regions results in skin that has increased pliability as well as increased elastic recoil. Although this study demonstrates the positive effect of onabotulinum toxin on biomechanical parameters, it is unclear what specific histological changes are occurring within the skin.