Jennifer Lynn Schiefer

A quantitative analysis of the venous outflow of the deep inferior epigastric flap (DIEP) based on the perforator veins and the efficiency of superficial inferior epigastric vein (SIEV) supercharging.

BACKGROUND While the arterial perfusion of the anterior abdominal wall has been extensively described in the literature, little has been published on the venous drainage of the deep inferior epigastric flap (DIEP). The present study was performed to further clarify the venous drainage of DIEP flap, which remains a common vascular complication of this flap. METHODS We assessed the efficiency of venous outflow on 19 patients undergoing DIEP flap breast reconstruction, determining relative haemoglobin concentration (rHB) as an indicator of venous congestion. After the flap had been isolated on the perforator vessels, a selective clamping and declamping of the single lateral and medial perforator was performed and several measurements were carried out using a micro-lightguide spectrophotometer device (O2C: Oxygen to See; LEA Medizintechnik, Gießen, Germany). In addition, the efficacy of venous supercharging with ipsilateral and contralateral superficial inferior epigastric veins (SIEVs) was quantified. RESULTS For the sake of simplicity, we applied the classic perfusion zones of the lower abdomen as suggested by Hartrampf (1983). Regardless of lateral or medial DIEP perforator veins, zone IV showed the least venous outflow, while we observed the highest drainage in zone I. There was no significant difference between the venous drainage of the two immediately adjacent zones II and III. Supercharging with the contralateral SIEV showed a significantly better venous drainage in the contralateral zones II and IV, whereas the ipsilateral SIEV did not present any significant improvement in the venous drainage of any zone. CONCLUSION This study evaluated the characteristics of the venous outflow of the DIEP flap, based on the single perforator and the SIEVs. Our findings revealed that zones II and III have a similar venous drainage regardless of the perforator veins used. The supercharging of the contralateral SIEV leads to an improved venous outflow compared to the ipsilateral SIEV. This may support surgeons in minimising venous complications and may improve the degree of DIEP flap survival.

Our initial learning curve in the enzymatic debridement of severely burned hands—Management and pit falls of initial treatments and our development of a post debridement wound treatment algorithm

INTRODUCTION Excisional surgical debridement (SD) is still the gold standard in the treatment of deeply burned hands, though the intricate anatomy is easily damaged. Previous studies demonstrated that enzymatic debridement with the bromelain debriding agent NexoBrid® (EDNX) is more selective and thus can preserve viable tissue with excellent outcome results. So far no method paper has been published presenting different treatment algorithms in this new field. Therefore our aim was to close this gap by presenting our detailed learning curve in EDNX of deeply burned hands. METHODS We conducted a single-center prospective observational clinical trial treating 20 patients with deeply burned hands with EDNX. Different anaesthetic procedures, debridement and wound treatment algorithms were compared and main pitfalls described. RESULTS EDNX was efficient in 90% of the treatments though correct wound bed evaluation was challenging and found unusual compared to SD. Post EDNX surprisingly the majority of the burn surface area was found overestimated (18 wounds). Finally we simplified our process and reduced treatment costs by following a modified treatment algorithm and treating under plexus anaesthesia bedside through a single nurse and one burn surgeon solely. Suprathel® could be shown to be an appropriate dressing for wound treatment after EDNX. Complete healing (less 5% rest defect) was achieved at an average of day 28. CONCLUSION EDNX in deep burned hands is promising regarding handling and duration of the treatment, efficiency and selectivity of debridement, healing potential and early rehabilitation. Following our treatment algorithm EDNX can be performed easily and even without special knowledge in burn wound depth evaluation.

Development of an animal frostbite injury model using the Goettingen-Minipig

BACKGROUND A standardized reproducible animal model is desirable to gain a better understanding in the pathophysiology of frostbite injury and to develop novel therapies. Little has been studied about frostbite injury models. The depth and extent were not always being controllable and consistent. Therefore, we developed a frostbite injury model using the Göttingen Minipigs. METHODS 42 frostbite injuries were inflicted on the abdomen of seven minipigs using an aluminium bar (300g, circular with a radius of 1cm) frozen with liquid nitrogen to -196°C. The bar was applied for 1, 3, 6, 12, 30 and 60s. Five hours after injury biopsies were performed and evaluated by the presence of denatured collagen, blood vessels, follicular epithelial cells and mesenchymal cells. RESULTS A large spectrum of frostbite injuries was obtained ranging from superficial, superficial partial, deep partial to full thickness. The depth of injury in the sets of frostbites was highly consistent (Pearson correlation ranged from r=0.89 to 0.94). CONCLUSION We described a simple, inexpensive and safe swine frostbite model. The accurate reproducibility of the depth of the frostbite injuries allows researchers to accurately plan frostbite studies.

Assessment of microcirculatory changes of cold contact injuries in a swine model using laser Doppler flowmetry and tissue spectrophotometry

BACKGROUND Until now, the exact pathophysiology of frostbite injuries is poorly understood. The aim of the study is to evaluate the perfusion changes of frostbite injuries to get a better understanding of the exact mechanism underlying the resulting tissue damage. Particular attention has been given to the differentiation of changes between the various injury depths. METHODS Cold contact injury ranging from superficial, superficial-partial, deep-partial to full thickness were generated using seven goettingen minipigs. The perfusion dynamics were assessed before and 3 h after the injuries were inflicted using the O2C-device, which combines a laser light, to determine blood flow, and white light to determine hemoglobin oxygenation and relative amount of hemoglobin. A total of 42 cold contact injuries were inflicted and 84 measurements were carried out. RESULTS In superficial and superficial partial injuries there was an increase in the blood flow (mean, 20 ± 2.4%, 15 ± 5.1%, respectively) and in the relative amount of hemoglobin (mean, 29 ± 9.1%, 28 ± 7.2%, respectively), whereas the hemoglobin oxygenation did not alter (mean, -0.15 ± 2.4%, -0.8 ± 3.1%, respectively). In deep partial injuries there was a decrease in the blood flow (mean range, -4 ± 2.1 to -17 ± 4.7%) and an increase in the relative amount of hemoglobin (mean range, 79 ± 17.2 to 93 ± 17.7%), whereas the hemoglobin oxygenation did not alter (mean range, -0.7 ± 3.1 to -2.9 ± 3.3%). In full thickness injuries there was a drop in the blood flow (mean range, -24 ± 7.6 to -27 ± 11.8%) and in the hemoglobin oxygenation (mean range, -16 ± 3.5 to -19 ± 2.5%) and an increase in the relative amount of hemoglobin (mean range, +126 ± 19.8 to 145 ± 10.9%). CONCLUSION The results of this study form a more precise pattern of cold contact injury perfusion changes, which can be a valuable tool to assess the degree of cold contact injury and furthermore the efficacy of novel diagnostic aids, therapeutics and treatment modalities.

Alteration of biomechanical properties of skin in acute cold contact injury

BACKGROUND The prevalence of acute cold injury has increased recently. Despite new research findings, these injuries and their resulting tissue damage are still not entirely understood. Especially, little is known about alteration of skin biomechanical properties. METHODS A total of 36 acute cold contact wounds with different depths were generated on the abdomen of six Göttingen minipigs. Alteration of biomechanical properties of skin was evaluated objectively after 15 and 360 min using a Cutometer device. Biopsies for histological evaluation were taken, and the depth of injury was correlated with biomechanical properties. RESULTS Calculated elasticity (Ue), firmness of skin (R0) and overall elasticity (R8) demonstrated a continuous decrease, whereas other parameters demonstrated an initial increase with increasing depth of injury 15 min after wound generation. All parameters showed an increase compared to healthy skin, 360 min after wound generation. Furthermore, an alteration of values over time was detected. CONCLUSION Alteration of biomechanical properties of skin is a function of damaged tissue structures. The presented results demonstrate a decrease of main elastic parameters with increasing depth of injury and indicate progressive tissue damage over time. Skin elasticity measurements are a valuable tool in acute cold contact injury depth assessment and may act as an influencing factor in management decisions.

A novel hand-shaped suprathel simplifies the treatment of partial-thickness burns.

OBJECTIVE: The standard therapy to treat superficial partial-thickness burns of the hand involves the application of skin substitutes such as Suprathel (PolyMedics Innovations GmbH, Denkendorf, Germany), which reduce pain significantly, thus allowing a fast mobilization and leading to a quicker restoration of function. The aim of this study was to simplify the application of Suprathel by using new precut hand-shaped bandages. METHODS: Suprathel sheets have been produced in precut hand shapes that can be applied on the palm or on the dorsum of the hand. During a 6-month study period, 24 patients were treated with Suprathel after a burn injury of the hand. Half the patients received standard Suprathel sheets, and half received the novel hand-shaped Suprathel. Application time and material waste were documented closely. RESULTS: By using the Hand-Suprathel, application time was significantly reduced up to 80% compared with the standard rectangular Suprathel sheets. When the standard Suprathel sheet was reduced to the size and shape of the hand, approximately 40% of the material was discharged. In contrast, almost no material waste occurred by using Hand-Suprathel. CONCLUSION: The use of the new Hand-Suprathel increases efficiency because of its convenient and faster application, as well as by reducing material waste.

Thermoregulatory response of anterolateral thigh flap compared with latissimus dorsi myocutaneous flap: An evaluation of flaps cutaneous flow and velocity due to thermal stress

Introduction: Although, the success of free flaps has increased in the last years, more details about its characteristics might improve the clinical outcome of the flaps. This study examined the thermoregulatory ability as a sign of neural re‐innervation of two different types of microsurgical free flaps in the postoperative course. Methods: A total of 22 patients were examined after grafting two different flap types: The latissimus dorsi myocutaneous (LDM) flap (n = 11) and the anterolateral thigh (ALT) flap (n = 11). Patients were examined 6 and 9 months postoperatively. After exposure to cold and warm water (10°C and 35°C), multiple measurements were performed with the focus on blood velocity and flow using the “O2C” device. Results: Both examined flaps showed a tendency for improvement in local blood flow and velocity due to thermal stress. We recorded a more physiological thermoregulation during thermal stress for the LDM flap, when compared with the ALT flap over a measured period of time. Conclusion: We believe that the presence of the muscle portion in the LDM flap may offer better conditions for thermoregulation based on the improvement of neural and vascular regeneration. However, further studies should clarify the pathophysiological backgrounds, to make these interesting results clinically applicable.

Etiology, incidence and gender-specific patterns of severe burns in a German Burn Center - Insights of 25 years

INTRODUCTION Burns often require special treatment in specialized burn centers. One of the specialized German burn centers is located in Cologne-Merheim. Only little is known about the etiology of burns in Germany, their monthly distribution and changes over the past 25 years. METHODS We therefore retrospectively analyzed the etiology for all patients treated at the burn intensive care unit (BICU) of Cologne in the last 25 years and categorized them into groups. Thereafter all groups were analyzed according to distribution of age, gender and occurrence. RESULTS In this way we were able to show that the number of severe burns did not decrease over the time under evaluation and that it did not show seasonal variation. Injured females were older than males but fewer in number. The highest numbers of burns were related to fire, followed by electricity, hot liquids, chemicals and heat contact. Work-related burns occurred mostly with males. However, most of the burns were not work-related for either gender. CONCLUSION The number of burns in Germany and in the world is still high, and prevention strategies do not always have the desired effect. This study aims to fill the gap in published burn knowledge in Germany by way of describing the gender differences and etiology characteristics. It can therefore help to identify risks and expand effective burn prevention strategies.

The use of collagen-based matrices in the treatment of full-thickness wounds

Chronic and complex full-thickness wounds have become increasingly prevalent. Besides autologous skin transplantation, innovative wound dressing products have gained interest, as the functional and esthetic outcome is still limited. In this respect, the effect of a novel modifiable collagen-gelatin fleece on the healing of deep dermal wounds was examined and compared with untreated controls and Matriderm(®). A total of 48 full-thickness skin defects were generated on six minipigs and treated with the novel collagen-gelatin fleece of different thicknesses in single or multiple application (n=36) or treated with Matriderm(®) in a single application (n=6), or the wounds were left untreated (n=6). Wound healing was analyzed planimetrically by wound closure per time and histologically with regard to epidermal thickness and cell density. Compared to untreated wounds, wound closure per time and histological skin quality with regard to the mean epidermal thickness and epidermal cell amount were enhanced in both treatment groups. Overall, the best results for the novel collagen-gelatin fleece were achieved for multiple applications with a thickness of 150g/m(2). The novel biomaterial shows accelerated and improved dermal wound repair in a minipig model. As the manufacturing process of the scaffold allows the integration of bioactive substances such as antibiotics and growth factors, we intend to design a composite biomaterial using this scaffold as a carrier matrix.

Enzymatic Versus Traditional Surgical Debridement of Severely Burned Hands: A Comparison of Selectivity, Efficacy, Healing Time, and Three-Month Scar Quality

Severe burns of the hands are extremely challenging, given their anatomic complexity and vulnerability. Although excisional debridement with autografting remains the standard of care (SOC), previous studies have shown that use of enzymatic debridement with bromelain (NexoBrid, EDNX) enables rapid, selective enzymatic debridement, preserving viable tissue. To date, only two studies accruing data on EDNX in this setting have been published. The current study was conducted to compare EDNX with traditional surgical debridement (TSD) of deep dermal and full-thickness hand burns. This single-center, controlled clinical trial included 40 patients, aged 18 to 76 years, with deep dermal burns of the hand. The first 20 patients were debrided surgically, and the other 20 patients were using EDNX for debridement. Therapeutic selectivity, time to complete debridement and healing, complications, and 3-month functional/esthetic outcomes were compared by group. EDNX (vs TSD) significantly reduced time to complete debridement after admission (0.95 day vs 7.750 days; P < .001) and treatments needed for complete debridement (1.05 vs 1.45; P < .001), improving burn depth evaluation (initially overestimated in 55% of EDNX-treated patients). The number of wounds requiring autografting was certainly reduced (15% vs 95%; P = .034), as was time to complete healing after first debridement (23.30 vs 32.00 days; P < .001), and early scar quality after 3 months was nearly equivalent, with only heightened local redness in the EDNX group (P < .001). Compared with TSD, EDNX was superior in burn depth evaluation, tissue preservation, completeness of debridement, and wound closure. Scar quality after 3 months did not differ substantially.