Immune-modulating properties of blue light do not influence reepithelization in vitro.

Phototherapy is gaining more attention in the treatment of various diseases. Especially, blue light seems to be a promising approach for wound healing promotion due to its antimicrobial and immune-modulating properties. Despite this, there is only little research focusing on the immune-modulating properties of blue light and its possible effects on wound healing. Therefore, we investigated the effects of blue light irradiation on peripheral blood mononuclear cells (PBMC) and the influence on reepithelization in vitro. PBMCs were irradiated with DermoDyne® (DermoDyne HealthCare, Berlin, Germany) and effects on cell viability, cytokine expression, and scratch wound closure were evaluated afterwards. Irradiated cells showed a higher Interleukin-γ concentration while irradiation reduced resazurin concentration in a time-dependent manner. No differences in reepithelization were detectable when keratinocytes were treated with the supernatant of these blue light irradiated PBMCs. Blue light-mediated ex vivo stimulation of PBMCs does not cause faster reepithelization in an in vitro setting. Further research is needed to investigate the wound healing effects of phototherapy with blue light.

The Influence of Topically Administered Heparin on Peripheral Microcirculation of the Skin: A Double-Blind, Randomized, Controlled Preliminary Study on 50 Healthy Subjects.

BACKGROUND: Venous thrombosis is the most common cause of flap failure in the first days after surgery. Although heparin is one of the most important antithrombotic substances and is implemented in the therapy of various diseases, there are only a few studies addressing its topical administration in the field of flap surgery. Especially, very little is known about the effects of topical heparin and its impact on microcirculation. In this study we evaluated to what extent topically administered heparin influences skin microcirculation (capillary venous oxygen saturation SO2, blood filling of microvessels, blood flow, and velocity) in healthy subjects. METHODS: Skin perfusion parameters on the forearm were measured with the O2C device in a double-blinded, controlled, and randomized study with 50 healthy subjects after administration of heparin ointment in three different concentrations and a control ointment (dexpanthenol). RESULTS: Topically administrated heparin slightly increased SO2 (max. 187 ± 285 SD or standard deviation % vs. 145 ± 129 SD %), flow (max. 264 ± 427 SD % vs. 151.74 ± 111 SD %), and velocity (max. 153 ± 149 SD % vs. 122 ± 56 SD %) after an incubation time of 60 minutes in comparison to control. No statistically significant difference could be detected regarding heparin concentration. CONCLUSION: As a first important step in possible future implementing of heparin as a topical administration in flap surgery, our data-although not statistically significant-indicate that heparin can improve microcirculation (SO2, flow) in healthy subjects. Nevertheless, further research in subjects with impaired microcirculation is necessary.

Complement activation at the interface of wound dressings and blood does not influence keratinocyte migration/proliferation in vitro.

Recently, we reported that some wound dressings caused complement activation at the interface of wound dressing and blood. Since complement activation is associated with impaired wound healing, we investigated whether this activation of the complement cascade at the interface of wound dressings and blood does impair reepithelialization in a scratch wound healing assay. Although some samples showed higher levels of the complement activation marker SC5b-9 in our study, reepithelialization of the samples did not significantly differ from the control group. Further studies have to clarify if complement activation at the interface of wound dressings and blood plays a relevant role in the healing process especially in long-time experiments.

A quantitative study of hydration level of the skin surface and erythema on conventional and microclimate management capable mattresses and hospital beds.

BACKGROUND: In addition to pressure itself, microclimate factors are gaining more attention in the understanding of the development of pressure ulcers. While there are already various products to reduce pressure on sore-prone areas to prevent pressure ulcers, there are only a few mattresses/hospital beds that actively influence skin microclimate. In this study, we investigated if microclimate management capable mattresses/hospital beds can influence skin hydration and skin redness/erythema. METHODS: We included 25 healthy subjects in our study. Measurements were made using Courage & Khazaka Multi Probe Adapter MPA with Corneometer CM825 and Mexameter MX18 to determine skin hydration of the stratum corneum and skin redness/erythema before and after the subjects were lying in conventional (Viskolastic® Plus, Wulff Med Tec GmbH, Fedderingen, Germany and Duo™ 2 mattress, Hill-Rom GmbH Essen, Germany) or microclimate management capable mattresses/hospital beds (ClinActiv + MCM™ and PEARLS AFT, Hill-Rom GmbH Essen, Germany). RESULTS: While there was no difference in skin redness/erythema on the different mattresses/hospital beds, skin hydration of the stratum corneum decreased significantly in an air fluidized bed compared to baseline values and values measured on standard mattress/Viskolastic® Plus. CONCLUSION: Air-fluidized therapy reduces skin hydration and therefore could contribute to prevent moisture associated ulcers. Changes in skin hydration as one important factor of skin microclimate can be detected after a short time of incubation and even before an erythema appears.

Hemocompatibility of different burn wound dressings.

A variety of wound dressing are available for burns. Furthermore, although their impacts on wound healing have been studied sufficiently, their effects on blood remain unclear. Meanwhile, this aspect is extremely important, since blood interacts with the wound dressing, especially in extensive burn injuries. Therefore, the aim of this study is to evaluate the hemocompatibility and immunogenicity of different burn wound dressings. Accordingly, human whole blood (n = 5) was anticoagulated with heparin, treated with different wound dressings and incubated at 37°C for 30 minutes. Different parameters for coagulation and hemocompatibility were evaluated before and after incubation. Consequently, Jelonet, Xenoderm, and Matriderm showed higher TAT-III concentrations, Jelonet, Xenoderm, EZ Derm, and Matriderm were higher ß-thromboglobulin; EZ Derm and Burntec showed higher SC5b-9 concentrations after incubation with whole blood. Our ex vivo study provided initial insights into the hemocompatibility and immunogenicity of different burn wound dressings. Moreover, Xenografts (Xenoderm and EZ Derm), Jelonet and Matriderm showed a hemostyptic effect, while EZ Derm and Burntec activated the complement system. Therefore, further studies must be conducted to analyze the possible effects in vivo.

Comparison of spontaneous sensory recovery of noninnervated anteromedial thigh flap, latissimus dorsi flap, and gracilis muscle flap in lower extremity reconstruction: A prospective comparative study.

BACKGROUND: We evaluated the time course and differences in the sensory recovery of three commonly used free flaps for lower extremity reconstruction. Furthermore, the sensory recovery of skin-grafted muscle and skin paddle in latissimus dorsi flaps (LDMF) were differentiated. METHODS: In a prospective study, 26 patients who had undergone free flap lower extremity reconstruction were enrolled. Among them, 9 received LDMF, 9 received gracilis muscle flaps (GMF), and 8 received anterior lateral thigh flaps (ALTF). The sensory recovery was investigated by using the Semmes-Weinstein test (SWT) at 6 and 12 months after the surgery. RESULTS: All flaps recorded spontaneous sensory recovery. The GMF showed the smallest anesthetic area after 12 months as compared with the ALTF and LDMF (1 ± 3% vs. 18 ± 39% (p < .05) vs. 35 ± 35% (p < .05), respectively). Qualitatively, ALTF exhibited the best sensory recovery with the lowest SWT values (ALTF 4.57 ± 1.12 vs. GMF 5.01 ± 0.81 8 [p < .05], vs. LDMF 5.84 ± 0.52 [p < .05]). The sensory recovery of skin-grafted muscle was superior to that of the skin paddle in the LDMF (anesthetic area 29 ± 36% vs. 54 ± 33% [p < .05], SWT 5.85 ± 0.60 vs. 6.30 ± 0.18 [p < .05], respectively). CONCLUSION: All flaps displayed spontaneous sensory recovery potential over the investigation period, which appeared to be influenced by the flap type and size. The LDMF skin paddle showed lower potential for sensory recovery as compared with the skin-grafted muscle area of the same flap. The GMF demonstrated a near-complete sensory recovery after 12 months.

Elastic Wrapping of Lower Extremity Free Flaps during Dangling Improves Microcirculation and Reduces Pain as well as Edema.

BACKGROUND: Free tissue transfer has become a common and safe reconstructive procedure. However, total or partial flap losses remain a looming threat, especially for lower extremity free flaps due to the gravitational challenge associated with dependency. Thus, the majority of microsurgical centers apply some kind of structured flap training. However, due to the lack of evidence, these differ greatly, for example, in the application of an elastic wrapping during dangling. Therefore, the aim of this study was to assess the impact of an elastic wrapping on free flap microcirculation, edema, and pain during dangling. METHODS: Standardized dangling was performed from postoperative day (POD) 6 to 9 in 30 patients with microvascular reconstruction of the lower extremity. The first dangling per day was performed without elastic wrapping, followed by another session with 30 mm Hg of elastic wrapping. Tissue oxygen saturation (StO2), regional hemoglobin content (rHb), and blood flow (BF) were continuously measured in the free flap; the circumference of the flap as well as pain was assessed. RESULTS: During wrapped dangling, BF as well as StO2 was significantly increased, while rHb was significantly lower on all PODs. Wrapped dangling was rated significantly more comfortable and the girth of the free flaps was significantly less after wrapped dependency when compared with unwrapped dangling. CONCLUSION: Dangling with an elastic wrapping with 30 mm Hg pressure improved flap microcirculation and reduced pain and edema formation.

Quantitative Analysis of Heel Skin Microcirculation Using Laser Doppler Flowmetry and Tissue Spectrophotometry.

OBJECTIVE: To examine perfusion changes in the heel skin of individuals with and without diabetes mellitus to understand how skin is pathologically affected by diabetes mellitus. METHODS: This case-control study was conducted at an academic hospital in Tuebingen, Germany. A total of 30 subjects were enrolled in the study: 15 with known type 2 diabetes mellitus and 15 without. Each subject was asked to lie in a supine position on a hard lateral transfer mat for 10 minutes. MAIN OUTCOME MEASURES: Heel perfusion was quantitatively assessed directly after relief of pressure and after 3 and 6 minutes after relief of pressure using laser Doppler flowmetry and tissue spectrophotometry. MAIN RESULTS: Directly after relief of pressure, blood flow increased in the superficial skin layers (2 mm below the surface of the skin) in both groups. However, in deep skin layers (8 mm below the surface of the skin), blood flow increased in patients with diabetes mellitus and decreased in healthy patients. Oxygen saturation (SO2) was higher in healthy subjects directly after pressure relief. CONCLUSIONS: The increase in blood flow in superficial skin layers indicates reactive hyperemia after exposure in both groups. The prolonged hyperemia in deep skin layers in patients with diabetes indicates increased tissue vulnerability. Despite the increase in blood flow in deep skin layers, the SO2 and thus supply of tissue in patients with diabetes were reduced.

Gelatin-Collagen Nonwoven Scaffold Provides an Alternative to Suprathel for Treatment of Superficial Skin Defects.

OBJECTIVE: To evaluate the effect of a new biologic gelatin-collagen nonwoven scaffold compared with a more common synthetic wound dressing on the healing of superficial wounds. METHODS: Three superficial wounds with a depth of 0.5 mm and a length of 2.4 cm were created on the flanks of six minipigs using a skin dermatome. One wound on each pig was treated with the new nonwoven scaffold, one with the more common synthetic wound dressing, and one functioned as an untreated control wound. All three wounds were then covered with a semipermeable, sterile, transparent film. RESULTS: After 7 days, complete wound closure of all wounds could be detected; epidermal thickness and the number of epidermal cells of all treated wounds were significantly increased compared with the control wounds. The nonwoven dressing showed slightly better results compared with the more common dressing. CONCLUSIONS: The nonwoven scaffold is an interesting and competitive material for promoting epidermal wound healing. Because it is a biologic dressing, it degenerates completely and does not have to be removed from the wound. Further research should be conducted to compare this new dressing with other currently available wound treatments.

A quantitative study of transepidermal water loss (TEWL) on conventional and microclimate management capable mattresses and hospital beds.

BACKGROUND: Transepidermal water loss (TEWL) is regarded as one of the most important parameters characterizing skin barrier integrity and has found to be higher in impaired skin barrier function. Reduced or low TEWL instead indicates skin barrier integrity or improvement. We evaluated if different mattresses/hospital beds can influence this skin barrier function by measuring TEWL before and after subjects lying in conventional and microclimate management capable mattresses/hospital beds. METHODS: We included 25 healthy subjects in our study. Measurements were made using Courage & Khazaka Multi Probe Adapter MPA with Tewameter TM300 to determine TEWL before and after the subjects were lying in conventional (Viskolastic® Plus, Wulff Med Tec GmbH, Fedderingen, Germany and Duo™ 2 mattress, Hill-Rom GmbH Essen, Germany) or microclimate management capable mattresses/hospital beds (ClinActiv + MCM™ and PEARLS AFT, Hill-Rom GmbH Essen, Germany). RESULTS: While there was no statistically significant difference in standard mattresses/hospital beds (22.19 ±â€¯12.99 and 19.80 ±â€¯11.48 g/hm2), the decrease of TEWL was statistically significant in both microclimate management capable mattresses/hospital beds we investigated (16.89 ±â€¯8.586 g/hm2 and 17.41 ±â€¯7.203 g/hm2) compared to baseline values (35.85 ±â€¯24.51 g/hm2). CONCLUSION: As higher TEWL announces impaired skin barrier function these findings indicate that the choice of the mattress/hospital bed is important for skin barrier function and microclimate management systems improve skin barrier function of the skin.

Analysis of Operative Techniques of Fractures of the First Metacarpal Base.

INTRODUCTION: Over time, the operative treatment of extra-articular and intra-articular fractures of the first metacarpal base has gained significant importance, and at present, there are many operative strategies available because of the different osteosynthesis procedures in practice today. PURPOSE: In this retrospective cohort study, we analyze the possible differences between 2 distinguished operative osteosynthesis techniques, in terms of patient outcome, operation time, duration of radiation exposure, and postoperative radiographic results. METHODS: Fifty-two patients operated on for first metacarpal extra-articular or intra-articular base fracture were investigated retrospectively by means of records. After reduction, osteosynthesis was performed on 34 patients with K-wires (group I), and on 18 patients with plates and/or screws (group II). Of the 52 patients, 19 were available for a prospective follow-up examination. RESULTS: After analyzing the operation time, a significant difference between the 2 operative techniques for epibasal and Bennett fractures (P = 0.0089 and P = 0.02) was recorded. Furthermore, for the time of radiation exposure, no significant difference could be detected. Also, no statistical difference was found between the 2 analyzed groups in terms of patient outcomes and postoperative radiographic results. CONCLUSIONS: The determined data of the operated extra-articular and intra-articular first metacarpal base fractures revealed approximately equal results for patient outcome, postoperative x-ray results, and time of radiation exposure during the operation. After analyzing the operation time of epibasal and Bennett fractures, we can recommend that the K-wire fixation is superior to the plate and/or screw osteosynthesis as a treatment, because of the associated benefits of keeping costs low without harming the patient in the long term.

Donor Site Location Is Critical for Proliferation, Stem Cell Capacity, and Osteogenic Differentiation of Adipose Mesenchymal Stem/Stromal Cells: Implications for Bone Tissue Engineering.

Human adipose mesenchymal stem/stromal cells (Ad-MSCs) have been proposed as a suitable option for bone tissue engineering. However, donor age, weight, and gender might affect the outcome. There is still a lack of knowledge of the effects the donor tissue site might have on Ad-MSCs function. Thus, this study investigated proliferation, stem cell, and osteogenic differentiation capacity of human Ad-MSCs obtained from subcutaneous fat tissue acquired from different locations (abdomen, hip, thigh, knee, and limb). Ad-MSCs from limb and knee showed strong proliferation despite the presence of osteogenic stimuli, resulting in limited osteogenic characteristics. The less proliferative Ad-MSCs from hip and thigh showed the highest alkaline phosphatase (AP) activity and matrix mineralization. Ad-MSCs from the abdomen showed good proliferation and osteogenic characteristics. Interestingly, the observed differences were not dependent on donor age, weight, or gender, but correlated with the expression of Sox2, Lin28A, Oct4α, and Nanog. Especially, low basal Sox2 levels seemed to be pivotal for osteogenic differentiation. Our data clearly show that the donor tissue site affects the proliferation and osteogenic differentiation of Ad-MSCs significantly. Thus, for bone tissue engineering, the donor site of the adipose tissue from which the Ad-MSCs are derived should be adapted depending on the requirements, e.g., cell number and differentiation state.

[Preservation of the outer ear in a complex burn injury]. / Erhalt des äußeren Ohres bei einer komplexen Verbrennung.

Saving the outer ear in burn injuries is a challenging task for the treating surgeon that should not be underestimated. Burns which are initially evaluated as superficial, particularly in this region, often have a tendency to undergo progressive tissue destruction whereby conservative treatment is often no longer sufficient to preserve the skin of the auricle with the underlying cartilage. Various possibilities for saving the ear and for ear reconstruction are described, but in the case of severely burned patients it is often necessary to carry out a quick and relatively simple treatment. In the complicated case of a severely burned patient involving the external ear, a good cosmetic result could be finally obtained with preservation of form and function by means of an economical cartilage resection with subsequent adaptation.

Facial microcirculatory and biomechanical skin properties after single high energy (Er):YAG laser application.

OBJECTIVE: Owing to skin aging and the growing demand for skin rejuvenation, minimal invasive aesthetic treatments such as laser procedures are increasingly coming into focus. However, until now, little has been known about the objective effects of these procedures with respect to skin microcirculation or changes in skin elasticity. STUDY DESIGN: Facial skin rejuvenation was performed on 32 volunteers using ablative Erbium: YAG laser. Skin microcirculation and skin elasticity have then been evaluated objectively. METHODS: Microcirculation (flow, SO2 , velocity, and rHB) has been analyzed before and directly after the laser session by using the O2C device. Skin elasticity has been evaluated by using the Cutometer device (Uf, Ua, Ur, and Ue) before and directly after the laser treatment, as well as 1 week and then 1, 3, and 6 months post treatment. Further, the outcome for the volunteers regarding their satisfactory level after laser treatment was evaluated. RESULTS: Twenty volunteers were available for a complete follow-up. Microcirculation displayed statistically significant increase in all values to 2 mm depth. The biomechanical skin parameter of firmness of skin displayed statistically significant improvement in superficial skin layer after 6 months. CONCLUSION: Concerning microcirculation and skin elasticity the ablative Erbium: YAG laser treatment revealed similar effects on the skin like a superficial burn injury. In contrast to the determined skin elasticity parameters, firmness of skin objectively revealed a skin tightening effect after 6 months. Along with the important epidermal effect, the suitability of ablative laser treatment for skin rejuvenation has been proved in a long-term follow-up. Lasers Surg. Med. 49:891-898, 2017. © 2017 Wiley Periodicals, Inc.

Growth Differentiation Factor 5 Accelerates Wound Closure and Improves Skin Quality During Repair of Full-Thickness Skin Defects.

BACKGROUND: A fast and stable wound closure is important, especially for extended and unstable wounds found after burn injuries. Growth can regulate a variety of cellular processes, including those involved in wound healing. Growth differentiation factor 5 (GDF-5) can accelerate fibroblast cell migration, cell proliferation, and collagen synthesis, which are essential for wound healing. Nevertheless, no standardized evaluation of the effect of GDF-5 on the healing of full-thickness wounds has been published to date. METHODS: Five full-thickness skin defects were created on the backs of 6 minipigs. Three wounds were treated with GDF-5 in different concentrations with the help of a gelatin-collagen carrier, and 2 wounds served as control group. The first was treated with the gelatin carrier and an Opsite film (Smith & Nephew, Fort Worth, Texas), and the other was treated solely with an Opsite film that was placed above all wounds and renewed every second day. RESULTS: Growth differentiation factor 5 accelerates wound closure (10.91 [SD, 0.99] days) compared with treatment with the carrier alone (11.3 [SD, 1.49] days) and control wounds (13.3 [SD, 0.94] days). Epidermal cell count of wounds treated with GDF-5 revealed a higher number of cells compared with the control group. In addition, mean epidermal thickness was significantly increased in GDF-5-treated wounds compared with the control wounds. CONCLUSIONS: Because of its ability to improve skin quality, GDF-5 should be considered when developing composite biomaterials for wound healing.

A Quantitative Analysis of Microcirculation in Skin Defects Covered with Topical Wound Dressings or a Newly Developed Collagen Matrix.

OBJECTIVE: Innovative skin substitutes and temporary wound dressings are frequently used in the treatment of superficial and partial-thickness wounds. The aim of this study was to compare 2 commonly used temporary skin dressings with a newly developed collagen matrix to determine changes in microcirculation as measured by blood flow, hemoglobin oxygenation, and relative hemoglobin values during healing of partial-thickness skin defects. METHODS: This animal study involved 28 adult male Lewis rats. On the back of each rat, 2 standardized partial-thickness skin defects were generated through a skin dermatome (n = 56). Then, wounds were treated with polylactide-based copolymer skin substitute (Suprathel, PolyMedics, Denkendorf, Germany; n = 14), biosynthetic skin dressing (Biobrane, Smith & Nephew, Hamburg, Germany; n = 14), or Collagen Cell Carrier (CCC; Naturin Viscofan, Weinheim, Germany; n = 14). The remaining control wounds were left untreated (n = 14). MAIN OUTCOME MEASURES: Perfusion dynamics were assessed every 10 days for 80 days with the O2C device (LEA Medizintechnik, Gießen, Germany) to determine blood flow, hemoglobin oxygenation, and relative amount of hemoglobin. MAIN RESULTS: Blood flow was increased in all wounds for at least 30 days after wound generation. The relative amounts of hemoglobin were increased in superficial layers (2 mm) for 10 to 20 days. Hemoglobin oxygenation in the superficial layers decreased in the polylactide-based copolymer skin substitute and biosynthetic skin dressing-treated groups and initially increased in the untreated wounds and CCC groups on day 10; these values also decreased. CONCLUSIONS: The presented results demonstrate the complex changes in microcirculation in the course of healing partial-thickness wounds with different wound dressings and contribute to a better understanding of these wounds. However, based on the results of the study, a clear recommendation for a specific substitute is not yet possible.

Determining the appropriate number and duration of leech therapy in congested tissues using tissue spectrophotometry and laser Doppler flowmetry.

A universal protocol determining the number of leeches and their application time does not exist. The aim of this study, therefore, is to quantify perfusion dynamics in venous congested tissues after leech application to get more detailed information about changes due to leech-induced skin microcirculation and to evaluate the usability of the Oxygen to See (O2C) device in terms of determining the appropriate number of leeches and the duration of therapy. Twelve patients with the need for leech therapy participated in the study. Perfusion dynamics of the congested tissue was assessed using the O2C device, which determines blood flow (BF), the relative amount of hemoglobin (rHB), and the oxygen saturation (SO2). Measurements were carried out before leech application and on various intervals like 10 minutes, one hour, and three hours after leech application. The leech application effectuated after 10 minutes a nonsignificant perfusion improvement, which further increased after one hour with a significant reduction of the relative amount of hemoglobin and a significant increase of blood flow and oxygen saturation (BF= +56.7%; rHB= -25.5%; SO2= +53.7%). After three hours, the values returned to the levels before leech administration. In two cases, in which further administration of leeches within the measurement period was necessary, no substantial perfusion changes were obtained. The results of this study forms a more precise pattern of microcirculatory changes of leech therapy in congested tissues. According to our measurements a venous drainage improvement can be expected in congested tissue one hour after leech administration. The O2C seems to be a useful method to determine the appropriate number and duration of leech therapy.

A Novel Collagen-Gelatin Scaffold for the Treatment of Deep Dermal Wounds-An Evaluation in a Minipig Model.

BACKGROUND: Today, autologous skin transplantation is frequently used for full-thickness skin defects. There is still a high demand for new wound-healing products to replace autologous skin transplantation. OBJECTIVE: In this context, the effect of a new collagen-gelatin scaffold on full-thickness skin defects was evaluated. MATERIALS AND METHODS: Four full-thickness skin defects were created surgically on the dorsum of 6 Göttingen minipigs. Three wounds were randomly treated with a novel collagen-gelatin scaffold in different thicknesses, whereas the fourth wound was left untreated and served as a control wound. During the experimental period of 21 days, a close-up photographic documentation was performed. Afterwards, the areas of the initial wounds were excised and examined histologically. RESULTS: The systematic evaluation of 24 wounds showed that treatment with the new collagen-gelatin scaffold led to an accelerated wound repair of 1.1 days. Compared to control wounds, it also demonstrated improved skin quality in regard to epidermal thickness. CONCLUSION: The new collagen-gelatin scaffold supports and accelerates dermal wound repair compared to untreated control wounds. Nevertheless, wound treatment with the scaffold was only performed on the first day. In further studies, the impact of multiple scaffold applications on full-thickness skin defects should be investigated.

Frequent Application of the New Gelatin-Collagen Nonwoven Accelerates Wound Healing.

OBJECTIVE: Mortality after chronic wounds is high. Thus, proper and effective therapy is of critical importance. Adult mammalian skin cannot regenerate spontaneously. It heals under scar formation in a process of repair. In general, wound closure is achieved through a combination of contraction, scar formation, and regeneration. To enhance wound healing, research groups are continuously inventing and evaluating novel skin replacement products. A single application of a new gelatin-collagen nonwoven accelerates wound closure of full-thickness skin defects. Therefore, the authors' objective was to evaluate the effect of a higher application frequency of the nonwoven on wound closure in a minipig model. MATERIALS AND METHODS: Four full-thickness skin defects were created surgically on the dorsum of 12 Göttingen minipigs. Next, 3 wounds were treated randomly with a novel gelatin-collagen nonwoven in different thicknesses, while the fourth wound was left untreated and served as the control wound. Moreover, 6 minipigs achieved multiple applications of the wound dressing. During the experimental period of 21 days, a close-up photographic documentation was performed. Finally, the areas of the initial wounds were excised and examined histologically. RESULTS: More frequent application of the nonwoven achieved accelerated wound healing and better epidermis quality compared with a single application. Mean time until wound closure of all wounds treated with a multiple application of the nonwoven was 11.0 (± 1.2) days, compared with a single application of the nonwoven with 12.4 (± 1.26) days and control wounds with 13.5 (± 1.19) days. Furthermore, the epidermal thickness of all wounds treated with multiple applications of the nonwoven was increased by 10.67 µm (31.89 ± 8.86 µm, P = .0007) compared with a single application of the nonwoven and by 6.53 µm (27.75 ± 7.24 µm, P = .0435) compared with the control group. CONCLUSIONS: Multiple applications of the gelatin-collagen nonwoven may be an appropriate treatment for chronic wounds leading to a fast wound closure through a combination of contraction and re-epithelialization.

Bilateral comparison of the vascular pattern of the superficial temporal artery based on digital subtraction angiography.

PURPOSE: This study was performed to investigate any bilateral differences in the vascular pattern and microsurgical relevant parameters of the superficial temporal artery (STA) in vivo. METHODS: Digital subtraction angiographies of the STA of 38 individuals were retrospectively analyzed. A bilateral comparison of the branching pattern as well as of surgically relevant diameters and lengths of the main branches of the STA was performed. Moreover, gender-specific differences were assessed. RESULTS: Only 10 cases (26%) demonstrated an identical type and subtype of the STA pattern bilaterally. The diameters of the STA at its origin and bifurcation level as well as of its parietal branch were statistically significant wider on the right than on the left side (p(o) = 0.0009, p(b) = 0.006, p(p) = 0.030). Moreover, the diameters of the STA at its origin level on the right side, at its bifurcation level on both sides and of the frontal branch on both sides were statistically significant wider in males than females. No statistically significant differences of the lengths of the STA and its main branches between the right and the left side were identified. CONCLUSION: The occurrence of the vascular pattern of the STA in vivo is random for each side of the same person and cannot be predicted by the vascular pattern of the opposite side. The calibers of the main branches of the STA are gender specific and commonly larger on the right than on the left side.