Skin Stretch Research Articles

A Two-Flap Combination for Auricular Elevation in Microtia Reconstruction.

The aims of this study were to describe and evaluate the effectiveness of combined flaps, a modification of the Nagata technique, for providing a reasonable projection for reconstructed auricles. The authors modified the Nagata method for covering the cartilage block by introducing a new combined flap technique, including the temporoparietal skin flap and retroauricular flap. The authors compared the shape, size, and position of the reconstructed ear to the opposite ear, and we evaluated postoperative complications and patient satisfaction levels. They verified the effectiveness of the combined flap by assessing flap necrosis, skin color, thickness, hair in the auricular area, and scars. A total of 38 consecutive patients (39 ears) with microtia, aged 6 to 34 years, underwent reconstruction using the modified method and were followed up for 33.6 months on average. The reconstructed auricle's shape was well defined, with 41.0% having good and 15.4% having excellent results. Most cases achieved good and acceptable levels in size, position, medial longitudinal axis angle, and auriculocephalic angles, and 79.9% of patients/their families were satisfied. The authors observed no cases of flap necrosis or hypertrophic scarring, and there were low rates of flap complications, such as unmatched skin color (7.7%), unacceptable thickness (5.1%), or hair and stretch marks (10.3%). The modified method's reconstructed ear achieved stable projection, symmetric appearance, and obvious anatomical landmarks with high patient satisfaction. The combined flap method showed certain advantages: high survival rate, less skin contrast, no hypertrophic scars, and fewer complications. Therapeutic, IV.

Percutaneous Removal of a Foreign Body From the Distal Phalanx Using a 14 Gauge Needle and Fluoroscopy

Percutaneous Removal of a Foreign Body From the Distal Phalanx Using a 14 Gauge Needle and Fluoroscopy

An analysis of the relationship between microneedle spacing, needle force and skin strain during the indentation phase prior to skin penetration

Microneedle (MN) array patches present a promising new approach for the minimally invasive delivery of therapeutics and vaccines. However, ensuring reproducible insertion of MNs into the skin is challenging. The spacing and arrangement of MNs in an array are critical determinants of skin penetration and the mechanical integrity of the MNs. In this work, the finite element method was used to model the effect of MN spacing on needle reaction force and skin strain during the indentation phase prior to skin penetration. Spacings smaller than 2–3 mm (depending on variables, e.g., skin stretch) were found to significantly increase these parameters.

Head rotation and illusory force sensation by lateral skin stretch on the face

Various methods for inducing an illusory force sensation to present a sense of force to users in energy-saving and space-saving systems have been proposed. One of them is the illusion of force sensation induced by cutaneous sensory stimulation. In this study, we hypothesized and empirically verified that lateral skin stretch alone on the face can induce an illusory force sensation in the direction of the stretch. We focused on the anterior temporal and cheekbone regions, in which the cushion part of the head-mounted display contacts the skin, and applied skin stretches of different intensities to these regions, envisioning a force presentation device built into the head-mounted display. Head rotations of approximately 40 and 50 degrees were generated by skin stretches in the anterior temporal and cheekbone regions, respectively, confirming the illusory force sensation in the direction of rotation. We confirmed a positive correlation between the head-turning angle and the amount of skin deformation. The intensity of the illusory force sensation can be controlled by changing the amount of lateral skin deformation; this may be applied to the development of a new force presentation head-mounted device.

Study on Size Estimation of Prosthesis in Rhinoplasty Based on Mechanical Test and Analysis.

Rhinoplasty is a common plastic surgery. The determination of prosthesis size for rhinoplasty has long been dependent on the surgeon's experience. Some of the patients suffered from complications after the surgery. In this paper, we present a method for estimating the size of prosthesis in rhinoplasty. A nasal tension tester is designed and implemented. On the basis of the mechanical theory of Hyperelastic Materials, an algorithm for inverse calculation of material parameters is proposed; On the basis of the material parameters, an algorithm for estimating the safety range of nasal stretch is established. The nasal tension tester can obtain the nasal tension data without harming the subject. Our results show that different subjects generally have different nasal skin elasticity and tolerance to skin stretch. Therefore, the selection of prosthesis size for rhinoplasty should not be generalized, but should be tested and calculated separately for each subject. The results of this study are helpful for doctors to quantitatively understand the skin condition of the subject 's nose and the safe range of nasal stretch, based on which the determination of prosthesis size can be made for rhinoplasty.

The spatial profile of skin indentation shapes tactile perception across stimulus frequencies

Multiple human sensory systems exhibit sensitivity to spatial and temporal variations of physical stimuli. Vision has evolved to offer high spatial acuity with limited temporal sensitivity, while audition has developed complementary characteristics. Neural coding in touch has been believed to transition from a spatial to a temporal domain in relation to surface scale, such that coarse features (e.g., a braille cell or corduroy texture) are coded as spatially distributed signals, while fine textures (e.g., fine-grit sandpaper) are encoded by temporal variation. However, the interplay between the two domains is not well understood. We studied tactile encoding with a custom-designed pin array apparatus capable of deforming the fingerpad at 5 to 80 Hz in each of 14 individual locations spaced 2.5 mm apart. Spatial variation of skin indentation was controlled by moving each of the pins at the same frequency and amplitude, but with phase delays distributed across the array. Results indicate that such stimuli enable rendering of shape features at actuation frequencies up to 20 Hz. Even at frequencies > 20 Hz, however, spatial variation of skin indentation continues to play a vital role. In particular, perceived roughness is affected by spatial variation within the fingerpad even at 80 Hz. We provide evidence that perceived roughness is encoded via a summary measure of skin displacement. Relative displacements in neighboring pins of less than 10 µm generate skin stretch, which regulates the roughness percept.

A Study on Artificial Kinesthesia Generation by Simultaneous Stimulation of Mechanical Vibration and Mechanical Skin Stretch.

Artificially controlled kinesthesia can be applied to many situations because kinesthesia is essential to recognizing body movements. It could be used to generate artificial kinesthesia in rehabilitation or daily motion assist to improve self-efficacy of the robot user. Moreover, the controlled artificial kinesthesia could make people feel as if they are performing the actions of the robotic limbs with their own limbs. Mechanical vibration stimulation is one of the candidates to artificially control kinesthesia. It is known that mechanical vibration stimulation on human muscles or tendons from skin surface evokes an illusion of movement as if the stimulated muscles are extended. That effect of artificial kinesthesia is called Kinesthetic Illusion (KI). In this paper, a method to increase the amount of KI without changing the frequency of the vibration stimulation is investigated by applying mechanical skin stretch stimulation at the same time with the mechanical vibration stimulation. The experiment was conducted by generating KI for flexion motion of the elbow joint on a horizontal plane to evaluate the proposed approach. In the experiments, three out of five subjects showed obvious increase in the amount of KI when skin stretch stimulation was applied at the same time with the mechanical vibration stimulation. The results of this study provide a first step toward artificial kinesthesia control using a wearable robotic device using the mechanical vibration stimulation.

Effectiveness analysis of disposable skin stretch closure in treatment of difficult to close skin and soft tissue defects

To observe the effectiveness of disposable skin stretch closure in the treatment of wounds with skin and soft tissue defects that were difficult to close. The clinical data of 13 patients with skin and soft tissue defects that were difficult to close treated with disposable skin stretch closure and met the selection criteria between July 2021 and February 2022 were retrospectively reviewed. There were 9 males and 4 females, the age ranged from 15 to 71 years with a mean of 39.8 years. The causes of injury included falling injury in 5 patients, traffic accident injury in 5 patients, and falling from height injury in 3 patients. The causes of skin soft tissue defects included open fractures in 4 patients, wound infection in 4 patients, osteomyelitis in 3 patients, degloving injury in 1 patient, and necrosis of skin graft in 1 patient. The injury was located at calf in 8 patients, calcaneus in 3 patients, pelvis in 1 patient, and plantar in 1 patient. The skin and soft tissue defects ranged from 5.0 cm×2.0 cm to 10.5 cm×6.5 cm. Wound conditions (wound closure and wound healing) and the presence or absence of complications were recorded. All 13 patients were followed up 32-225 days with a median of 164 days. The wound closure time ranged from 5 to 14 days, with a mean of 8.8 days. The wound closure speed ranged from 0.7 to 13.7 cm 2/day, with a mean of 3.6 cm 2/day. All wounds healed at grade A, and no complication such as skin edge injury, wound necrosis, infection, dehiscence, and edema occurred. No patient complained of pain or discomfort, and no obvious scarring was found during follow-up. The wound healing time ranged from 17 to 28 days, with a mean of 21.7 days. One of them was transferred to other department due to lung cancer condition changes after using disposable skin stretch closure, and the wound had directly healed without suturing at 17 days after operation. The effectiveness of disposable skin stretch closure in the treatment of wounds with skin and soft tissue defects that were difficult to close was exact, with short wound closure time, few complications, and easy operation.

The Effect of Kinesthetic and Artificial Tactile Noise and Variability on Stiffness Perception.

Robot-assisted minimally invasive surgeries (RAMIS) have many benefits. A disadvantage, however, is the lack of haptic feedback. Haptic feedback is comprised of kinesthetic and tactile information, and we use both to form stiffness perception. Applying both kinesthetic and tactile feedback can enable more precise feedback than kinesthetic feedback alone. However, during remote surgeries, haptic noises and variations can be present. Therefore, toward designing haptic feedback for RAMIS, it is important to understand the effect of haptic manipulations on stiffness perception. We assessed the effect of two manipulations using stiffness discrimination tasks in which participants received force feedback and artificial skin stretch. In Experiment 1, we added sinusoidal noise to the artificial tactile signal, and found that the noise did not affect participants' stiffness perception or uncertainty. In Experiment 2, we varied either the kinesthetic or the artificial tactile information between consecutive interactions with an object. We found that the both forms of variability did not affect stiffness perception, but kinesthetic variability increased participants' uncertainty. We show that haptic feedback, comprised of force feedback and artificial skin stretch, provides robust haptic information even in the presence of noise and variability, and hence can potentially be both beneficial and viable in RAMIS.

Role of Skin Stretch on Local Vascular Permeability in Murine and Cell Culture Models.

Background:Excessive mechanical forces, particularly skin stretch, have been implicated in pathological cutaneous scarring. We hypothesize that this reflects, in part, stretch-induced vessel leakage that provokes prolonged wound/scar inflammation. However, this has never been observed directly. Here, a mouse model was used to examine the effect of skin flap stretching on vascular permeability. An in vitro model with pseudocapillaries grown in a stretchable chamber was also used to determine the effect of stretching on endothelial cell morphology and ion channel activity.Methods:Murine skin flaps were stretched with a biaxial stretching device, after which FITC-conjugated-dextran was injected and imaged with fluorescence stereomicroscopy. Endothelial cells were induced to form pseudocapillary networks in an elastic chamber. The chamber was stretched and differential interference contrast microscopy was used to assess cell morphology. In other experiments, markers for Ca2+ influx and K+ efflux were added before a single stretch was conducted. Histamine served as a positive-control in all experiments.Results:Cyclic stretching (20%) increased the vascular permeability of skin flaps almost as strongly as histamine. Both stimuli also partially disrupted the pseudocapillary networks, induced cell contraction, and created gaps between the cells. Both stimuli caused sustained K+ efflux; stretching had a milder effect on Ca2+ influx.Conclusions:Excessive cyclical stretching strongly increased the vascular permeability of skin vessels and in vitro pseudocapillaries. This effect associated with increased K+ efflux and some Ca2+ influx. Inhibiting such early stretch-induced signaling events may be an effective strategy for treating and preventing hypertrophic scars and keloids.

The Role of Spatial and Modality Cues on Visual and Haptic Memory.

This study investigates the ability to remember a sequence of stimuli in two basic conditions: haptic and visual. Participants rely on a combination of modal and/or spatial information to perform a memory task. For this purpose, an experimental setup was developed based on the "Simon Says" memory game. Individuals receive a series of sensory stimuli and need to remember the sequence and repeat it. The stimuli in visual conditions are colored or white lights, and the stimuli in haptic conditions are vibration, hot, cold, and skin stretch. Results demonstrate that participants retained longer sequences in spatial conditions compared to the modal conditions. It is also demonstrated that participants performed better in visual conditions compared to haptic conditions. Participants were able to retain more complex spatial patterns and remember them faster in visual conditions compared to haptic conditions. A spatial difficulty ranking system was developed, indicating how easily each spatial pattern can be retained visually and haptically.

Effect of Tactile Masking on Multi-Sensory Haptic Perception.

Multi-sensory wearable haptic devices are able to encode a variety of information using multiple haptic cues. However, simultaneous cues can be misperceived due to tactile masking effects. In this paper, we investigate the effect of masking on the perception of skin stretch and squeeze. We performed three experiments measuring the just-noticeable difference (JND) and the absolute threshold of skin stretch and squeeze alone and in the presence of simultaneous haptic cues. Additionally, we investigate the relative perceptual amplitudes of these haptic cues. Results indicate that the JND for a skin stretch cue increases with a masking squeeze cue, while the JND for a squeeze cue does not change with a masking stretch cue. Also, masking has a significant effect on the absolute threshold of both skin stretch and squeeze. These results suggest that the effect of masking diminishes as haptic cues become larger in amplitude. The results from the subjective equality experiment suggest a potential nonlinear relationship between perceptual magnitudes. Further testing should be carried out to investigate this relationship. Future multi-sensory devices can use these perceptual experiment findings to ensure the delivery of salient cues to users.

Wound-contractible hydrogel for skin regeneration, a new insight from mechanobiology

Wound-contractible hydrogel for skin regeneration, a new insight from mechanobiology

Pressure Stimulus to the Palm Substitutes and Augments Force Sensation.

Studies on pseudo-force feedback have reported that tactile stimuli such as skin stretch and pressure can substitute force sensation. This effect has enabled the design of a compact haptic device. However, little is known about the effect of applying pressure to the palm in terms of force substitution and augmentation, especially regarding how active and passive pressure stimuli differ. This article examines the pseudo-force effect of pressure stimuli to the palm, focusing on how it is perceived when it is applied together with a force stimulus. The method of adjustment was utilized, by which participants voluntarily moved their hands to adjust the pressure and force stimuli. The participants did this such that they felt a force equivalent to that of the reference applied to the other hand, which induced only a force stimulus. The results showed that the force sensation was significantly changed by the pressure stimulus to the palm, showing the effect of force substitution and augmentation. Furthermore, we found that there is no significant difference between the active and passive stimuli.

SuP-Ring: A pneumatic tactile display with substitutional representation of contact force components using normal indentation.

Shear force is important for tumour detection and can contribute to minimally invasive surgery (MIS). A popular method uses lateral skin stretch to produce shear force but has some limitations. We have developed a ring-type pneumatic tactile display that employs normal indentation substituted for lateral skin stretch to represent normal and shear feedback, called SuP-Ring. Psychophysical experiments were conducted to evaluate how users perceive the provided feedback and the effectiveness of SuP-Ring in tumour localisation. The experimental results show that the participants could perceive the provided normal and shear feedback well. Shear feedback enables users to enhance their performance in localising the tumour and normal feedback could contribute to ensuring the safety requirements in MIS. The proposed tactile display could be useful for intraoperative tumour localisation and has the potential to be used in a wide variety of applications.

Relationship between skin hydration and stretch marks

Background: Stretch marks are harmless skin disorders but can cause cosmetic and psychological problems. The mechanism in the pathogenesis of stretch marks is still not well known yet. However, it is most related to changes in the extracellular matrix components, including fibrillin, elastin and collagen. Skin hydration can affect the primary mechanism of its pathogenesis. This study determined the relationship between skin hydration and stretch marks.Methods: This was a cross sectional study with a total sampling method, involving 84 female residents from the Faculty of Medicine, Universitas Sumatera Utara batch 2020. The diagnosis of stretch marks is made through history taking and physical examination. The skin hydration checking was conducted on the right and left femur by using Corneometer CM 825 device. The data collected were analyzed by using the Kruskal Wallis test. The Ethical Committee of Universitas Sumatera Utara has approved this study.Result: The majority of ages ranged from 26-35 years (86,1%). Subjects who had a pregnant history with stretch marks were 44,6%. The majority of stretch marks located in the subjects were femur 45,5%. Skin hydration 65,5% of subjects was classified as dry. Skin hydration in subjects with stretch marks was lower than those without stretch marks with a p-value <0,001. There is a relationship between skin hydration and stretch marks with a p-value <0,001.Conclusion: There is a significant relationship between skin hydration and stretch marks.

Treatment of striae distensae: recent conceptions

Stretch marks (striae distensae) are linear areas of cutaneous atrophy that appear in regions of greatest stretch of the skin. Their formation is a complex multifactorial process, its etiopathogenesis has not been fully understood yet. Aesthetic correction of stretch marks is an urgent problem of modern dermatocosmetology due to their widespread prevalence and pronounced negative impact on the patient’s quality of life. The aim of this paper was to provide a review of the literature on current reported treatment options for stretch marks. The principles of the effect of various methods of treatment, their classification and data from clinical trials are considered.

A new approach of inducing proprioceptive illusion by transcutaneous electrical stimulation

BackgroundNeurotraumas or neurodegenerative diseases often result in proprioceptive deficits, which makes it challenging for the nervous system to adapt to the compromised sensorimotor conditions. Also, in human machine interactions, such as prosthesis control and teleoperation, proprioceptive mismatch limits accuracy and intuitiveness of controlling active joints in robotic agents. To address these proprioceptive deficits, several invasive and non-invasive approaches like vibration, electrical nerve stimulation, and skin stretch have been introduced. However, proprioceptive modulation is still challenging as the current solutions have limitations in terms of effectiveness, usability, and consistency. In this paper, we propose a new way of modulating proprioception using transcutaneous electrical stimulation. We hypothesized that transcutaneous electrical stimulation on elbow flexor muscles will induce illusion of elbow joint extension.MethodEight healthy human subjects participated in the study to test the hypothesis. Transcutaneous electrodes were placed on different locations targeting elbow flexor muscles on human subjects and experiments were conducted to identify the best locations for electrode placement, and best electrical stimulation parameters, to maximize induced proprioceptive effect. Arm matching experiments and Pinocchio illusion test were performed for quantitative and qualitative analysis of the observed effects. One-way repeated ANOVA test was performed on the data collected in arm matching experiment for statistical analysis.ResultsWe identified the best location for transcutaneous electrodes to induce the proprioceptive illusion, as one electrode on the muscle belly of biceps brachii short head and the other on the distal myotendinous junction of brachioradialis. The results for arm-matching and Pinocchio illusion tests showed that transcutaneous electrical stimulation using identified electrode location and electrical stimulation parameters evoked the illusion of elbow joint extension for all eight subjects, which supports our hypothesis. On average, subjects reported 6.81° angular illusion of elbow joint extension in arm-matching tests and nose elongated to 1.78 × height in Pinocchio illusion test.ConclusionsTranscutaneous electrical stimulation, applied between the the synergistic elbow flexor muscles, consistently modulated elbow joint proprioception with the illusion of elbow joint extension, which has immense potential to be translated into various real-world applications, including neuroprosthesis, rehabilitation, teleoperation, mixed reality, and etc.

The use of microneedling in cosmetology

Mesotherapy is one of the minimally invasive methods that guarantee relatively quick and long-lasting effects. Its purpose can be considered on many levels, because the research conducted in this area points to more and more new applications for mesotherapy. This article presents skin areas that can be subjected to mesotherapy and examples of substances used to achieve a specific result. Currently, the most common reasons for people to take advantage of the procedure include: the progressive aging process, wrinkles, skin discoloration, acne scars, bruises under the eyes, flabbiness, dryness and loss of skin elasticity, lipodystrophy, stretch marks or excessive hair loss. For the effects of the treatment to be satisfactory and long-lasting, it is suggested to perform mesotherapy in series to maintain optimal skin condition.

The selected stretch marks therapies used in beauty salons

Skin stretch marks are changes common to both women and men of all ages. Eliminating them is difficult and often does not bring the expected results. The aim of the study was to review methods that reduce visibility and eliminate stretch marks. Most treatments give visible results in the case of stretch marks in the inflammatory phase. In order to eliminate white stretch marks, combined therapies must be used in the atrophy phase. It is recommended to use exfoliating preparations, laser therapy, radiofrequency and more and more popular micro-needle methods, which, when used in accordance with the recommendations, give great hope for the effectiveness of the therapy. Individually selected cosmetology therapy can not only improve the appearance of the skin with stretch marks, but also restore self-confidence.