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The rat sciatic nerve (SN) is the most frequently used model in experimental research on peripheral nerve injuries. Within the broad range of evaluation methods to determine the experimental outcome, recovery of behavior represents the major criterion to assess functional regeneration. The grasping test indicates when recovery begins and its improvement with time. However, lesions of the SN have yet remained unstudied with this method. Therefore, rats received a SN resection and were divided into experimental groups: 1) control with lesion only, 2) nerve bridge, and 3) autograft. During weekly sessions, the grasping test measured the grip strength, and the locomotor behavior was assessed in the open field. Finally, the nerves were prepared for electrophysiology and histomorphometry. Autograft recovered grasping after 7 weeks with the strongest improvement afterwards. Nerve tube allowed grasping by week 12. Control animals did not recover. In the open field, no differences were observed between the groups. Recordings were possible only in the autograft group, which could be explained by higher number of regenerated fibers. This study indicates that grasping data correspond with physiological and anatomical findings. We conclude that the grasping test is a valid method to evaluate functional recovery after SN resection in rats.

ZusammenfassungKürzlich haben mehrere neue Technologien zur Unterstützung von Mikrochirurg:innen eine europäische Marktzulassung erhalten. Der vorliegende Artikel fasst die Eindrücke eines Expertenpanels zur Einordnung des Potentials neuer Technologien im Hinblick auf Nutzen für den Operateur, spezifische Indikationen und ökonomische Aspekte während der 42. Jahrestagung der Deutschsprachigen Arbeitsgemeinschaft für Mikrochirurgie der peripheren Nerven und Gefäße (DAM) in Graz, Österreich zusammen und diskutiert diese. Das Expertengremium befasste sich im Allgemeinen mit den Grundsätzen und Voraussetzung der erfolgreichen Etablierung neuer Technologien und im Speziellen mit neuartigen optischen und robotischen Systemen. Dazu wurde die aktuelle wissenschaftliche Literatur aufgearbeitet sowie anfängliche klinische Erfahrungswerte im Rahmen von Fallserien und retrospektiven Studien durch die Mitglieder des Expertenpaneels präsentiert. In der sich anschließenden Diskussion wurde herausgearbeitet, dass zunächst eine Identifizierung von Patienten-Untergruppen notwendig sein wird, bei denen mit dem Einsatz der neuen Technologien am ehesten ein klinischer Nutzen zu erzielen sei. Da bereits eine klinische Zulassung einiger Systeme gegeben ist, kann bei der unmittelbaren klinischen Anwendung eine Vorgehensweise von möglichst einfachem Einsatz hin zu immer feineren Anwendungen, also von der Mikro- bis hin zur Supermikrochirurgie, hin entwickelt werden. Eine Finanzierung kostenintensiver Systeme sei zunächst vermutlich nicht über den Erlös aus der Regelversorgung, sondern nur durch Fördergelder oder subventionierte klinische Studien möglich. In einer abschließenden Befragung sieht die Mehrheit der Sitzungsteilnehmenden die Notwendigkeit einer Preisreduktion sowohl der Technologien zur Visualisierung als auch der Operationsrobotik, um eine flächendeckende klinische Etablierung zu ermöglichen. Ebenfalls eine Mehrheit der Teilnehmenden würde bei klinischem Einsatz eine Kombination aus Exoskop bzw. robotischem Mikroskop und einem Operationsroboter bevorzugen. Die vorliegende Konsensusarbeit adressiert die Entwicklung einer Strategie zur effektiven Etablierung neuer Technologien, die die operative Qualität ausgewählter Eingriffe weiter erhöhen soll.

ZusammenfassungDie DIEP- (Deep inferior epigastric Perforator) oder muskelsparende transverse Rectus-abdominis-Myokutan-Lappenplastik (ms-TRAM) gilt als Gold-Standard in der autologen Brustrekonstruktion bei post-Mastektomie Patientinnen. Einige Patientinnen sind aus verschiedenen Gründen keine geeigneten Kandidatinnen für eine Gewebeentnahme am Bauch. In diesen Fällen stehen diverse andere Hebestellen am Oberschenkel (transverse und diagonale myokutane musculus gracilis Lappenplastik, profunda artery perforator Lappenplastik, lateral thigh perforator Lappenplastik), am Stamm (Lumbalarterienperforator-Lappenplastik) und aus der Gesäßregion (superiore und inferiore Glutealarterien und fasziokutane infragluteale Lappenplastik) zu Verfügung. Dieser Artikel gibt einige Einblicke in die Historie, die relevante Anatomie, die chirurgische Technik und neue Anwendungen wie die Neurotisation alternativer Lappenplastiken zur autologen Brustrekonstruktion.

Background There is still no consensus regarding the ideal zoning in abdominal-based autologous breast reconstruction using free DIEP or ms-TRAM flaps. In particular, the perfusion pattern of the flap according to the number of perforators used and their location remains controversial. In this study, the perfusion of free DIEP and ms-TRAM flaps is assessed intraoperatively and analyzed with regard to different perfusion patterns. Methods A retrospective analysis of 100 free flaps for breast reconstruction was performed. Following complete flap harvest, we used indocyanine green angiography for perfusion analysis. By applying two different contour levels, DIEP flaps with lateral or medial perforators and ms-TRAM flaps were assessed for their respective perfusion patterns. Results No statistically significant differences were found in the size of the perfusion area between the different flap types when applying the contour level of 20% (p >0.05). For the contour level of 30%, however, statistically significant differences were found between DIEP flaps with medially or laterally located perforators (p = 0.038). Laterally or medially located perforators in DIEP flaps showed no significant differences in their ability to cross the midline (contour level 20%, p = 0.068; contour level 30%, p = 0.058). Conclusion Considering the variability of the perfusion of the abdominal wall and the high sensitivity of indocyanine green angiography for their detection, the abdominal zonings play a minor role. By using intraoperative indocyanine green angiography, a precise and patient-specific free flap surgery for autologous breast reconstruction is possible independent of perforator location.

Recently, several new technologies to support microsurgeons have received European market approval. This article summarizes and discusses the impressions of an expert panel to classify the potential of new technologies in terms of benefits for the surgeon, specific indications and economic aspects during the 42nd Annual Meeting of the German-speaking Working Group for Microsurgery of Peripheral Nerves and Vessels (DAM) in Graz, Austria. In general, the expert panel addressed the principles and prerequisite for the successful establishment of new technologies and, in particular, novel optical and robotic systems. For this purpose, the current scientific literature was reviewed and initial clinical experience in the context of case series and retrospective studies was presented by the members of the expert panel. In the ensuing discussion, it was pointed out that it will first be necessary to identify patient subgroups in which the use of the new technologies is most likely to achieve a clinical benefit. Since clinical approval has already been granted for some systems, an approach can be developed for immediate clinical application from the simplest possible use to ever finer applications, i. e. from microsurgery to supermicrosurgery. Initially, funding for cost-intensive systems would presumably not be possible through revenue from standard care, but only through grants or subsidized clinical trials. In a final survey, the majority of meeting participants see the need for a price reduction of both visualization and surgical robotics technologies to enable widespread clinical establishment. Likewise, a majority of participants would prefer a combination of an exoscope or robotic microscope and a surgical robot for clinical use. The present consensus work addresses the development of a strategy for the effective establishment of new technologies, which should further increase the surgical quality of selected interventions.Kürzlich haben mehrere neue Technologien zur Unterstützung von Mikrochirurg:innen eine europäische Marktzulassung erhalten. Der vorliegende Artikel fasst die Eindrücke eines Expertenpanels zur Einordnung des Potentials neuer Technologien im Hinblick auf Nutzen für den Operateur, spezifische Indikationen und ökonomische Aspekte während der 42. Jahrestagung der Deutschsprachigen Arbeitsgemeinschaft für Mikrochirurgie der peripheren Nerven und Gefäße (DAM) in Graz, Österreich zusammen und diskutiert diese. Das Expertengremium befasste sich im Allgemeinen mit den Grundsätzen und Voraussetzung der erfolgreichen Etablierung neuer Technologien und im Speziellen mit neuartigen optischen und robotischen Systemen. Dazu wurde die aktuelle wissenschaftliche Literatur aufgearbeitet sowie anfängliche klinische Erfahrungswerte im Rahmen von Fallserien und retrospektiven Studien durch die Mitglieder des Expertenpaneels präsentiert. In der sich anschließenden Diskussion wurde herausgearbeitet, dass zunächst eine Identifizierung von Patienten-Untergruppen notwendig sein wird, bei denen mit dem Einsatz der neuen Technologien am ehesten ein klinischer Nutzen zu erzielen sei. Da bereits eine klinische Zulassung einiger Systeme gegeben ist, kann bei der unmittelbaren klinischen Anwendung eine Vorgehensweise von möglichst einfachem Einsatz hin zu immer feineren Anwendungen, also von der Mikro- bis hin zur Supermikrochirurgie, hin entwickelt werden. Eine Finanzierung kostenintensiver Systeme sei zunächst vermutlich nicht über den Erlös aus der Regelversorgung, sondern nur durch Fördergelder oder subventionierte klinische Studien möglich. In einer abschließenden Befragung sieht die Mehrheit der Sitzungsteilnehmenden die Notwendigkeit einer Preisreduktion sowohl der Technologien zur Visualisierung als auch der Operationsrobotik, um eine flächendeckende klinische Etablierung zu ermöglichen. Ebenfalls eine Mehrheit der Teilnehmenden würde bei klinischem Einsatz eine Kombination aus Exoskop bzw. robotischem Mikroskop und einem Operationsroboter bevorzugen. Die vorliegende Konsensusarbeit adressiert die Entwicklung einer Strategie zur effektiven Etablierung neuer Technologien, die die operative Qualität ausgewählter Eingriffe weiter erhöhen soll.

ZusammenfassungDas Lymphgefäßsystem ist essenziell für den Rücktransport interstitieller Flüssigkeit aus dem Gewebe zurück in den Blutkreislauf. Bei Störungen des komplexen Netzwerkes kommt es zur Ausbildung von Ödemen und der Ansammlung und Ablagerung von Proteinen und Lipiden in der betroffenen Region. Obwohl das Lymphsystem schon seit Jahrhunderten Gegenstand der Forschung ist, haben lymphologische Krankheitsbilder wie das Lymphödem als mögliche Folge onkologischer Therapien erst in den vergangenen Jahren an Aufmerksamkeit gewonnen. So liegt die Inzidenz des sekundären Lymphödems, das durch traumatische, infektiöse oder iatrogene Schädigung auftritt, zwischen 0,13 und 2 % und betrifft meist Frauen. Auch das davon abzugrenzende Lipödem ist in den letzten Jahren zunehmend in den Fokus der Öffentlichkeit gerückt. Beide Erkrankungen können mit einer schmerzhaften Umfangsvermehrung, einer beruflichen und alltäglichen Einschränkung und einer Reduktion der Lebensqualität einhergehen. Neben der klinischen Untersuchung und Anamnese gewinnen neue bildgebende Verfahren eine zunehmende Bedeutung zur Verbesserung der Diagnosestellung, Stadieneinteilung und Therapieplanung, wenngleich immer noch oftmals Monate bis Jahre bis zur korrekten Diagnosestellung vergehen. Während konservative Therapiemethoden wie die komplexe physikalische Entstauungstherapie weiterhin die Grundlage der Behandlung bilden, kommen zunehmend auch operative Verfahren bei der Therapie des Lymphödems zum Einsatz. Hierbei unterscheidet man die reduzierenden Verfahren, die hauptsächlich auf die Symptomreduktion abzielen, von den rekonstruktiven Verfahren zur Wiederherstellung des Lymphsystems mittels mikrochirurgischer Techniken. Nachfolgend werden verschiedene operative Therapiemöglichkeiten in der Lymphologie dargestellt.

Nerve compression syndromes are referred to as chronic irritation or pressure palsies of peripheral nerves in areas of preformed anatomical constriction. Carpal tunnel syndrome is the most common nerve compression syndrome, followed by cubital tunnel syndrome. In addition, less frequent nerve compression syndromes of the upper extremities that affect the median, ulnar or radial nerves have been described. This review provides an overview of current treatment options for nerve compression syndromes of the upper extremities.Systematic overview.Based on established national (AWMF) and international guidelines as well as the Cochrane Library, we performed a systematic literature search on PubMed (NLM), focusing on randomised controlled trials.Over the research period (2012 - 2020), there were 43 randomised trials that investigated surgical carpal tunnel release methods, 68 that compared different conservative therapies and 12 that compared surgical versus conservative treatments. Furthermore, eight studies analysed surgical techniques and four analysed conservative techniques for cubital tunnel syndrome. No randomised trials were conducted on the less common peripheral nerve compression syndromes, but case reports and observational studies were conducted.For carpal and cubital tunnel syndromes, there are evidence-based diagnostic methods as well as therapeutic recommendations based on randomised and controlled trials. When diagnosis is made after clinical examination and supported by radiological and electrophysiological evaluation, surgical treatment is considered superior to conservative treatment. In particular, excellent long-term results can be achieved by surgery for carpal and cubital tunnel syndromes. More controlled studies are needed to establish evidence-based therapeutic recommendations for the less common nerve compression syndromes, which are somewhat controversially and inconsistently defined.Als Nervenkompressionssyndrome bezeichnet man chronische Druckläsionen peripherer Nerven im Bereich präformierter anatomischer Engstellen. Hierbei bildet das Karpaltunnelsyndrom das häufigste Engpasssyndrom eines peripheren Nervs, gefolgt vom Kubitaltunnelsyndrom. Daneben gibt es an der oberen Extremität noch seltener vorkommende Engpasssyndrome des N. medianus, N. ulnaris und N. radialis. Die vorliegende Übersichtsarbeit soll den aktuellen Stand bez. der Therapiemöglichkeiten und -empfehlungen für die Behandlung von Nervenkompressionssyndromen der oberen Extremität darstellen.Systematische Übersichtsarbeit.Ausgehend von bestehenden nationalen (AWMF) und internationalen Leitlinien sowie der Cochrane Library führten wir eine systematische Literaturrecherche über PubMed (NLM) mit dem Fokus auf randomisiert kontrollierte Studien durch.Zum Zeitpunkt der Recherche (12 – 2020) existieren für das Karpaltunnelsyndrom 43 randomisierte Studien zum Vergleich der operativen Techniken, 68 zum Vergleich nicht operativer Therapien und 12 zum Vergleich der operativen mit nicht operativen Therapien. Für das Kubitaltunnelsyndrom existieren 8 randomisierte Studien zum Vergleich der operativen Techniken und 4 zum Vergleich der nicht operativen Techniken. Für die selteneren peripheren Nervenkompressionssyndrome existieren keine randomisierten Studien, es dominieren Fallberichte und Beobachtungsstudien zu den einzelnen Entitäten.In Bezug auf das Karpaltunnel- und das Kubitaltunnelsyndrom existieren sowohl evidenzbasierte Diagnoseverfahren als auch Therapieempfehlungen, die randomisiert kontrolliert belegt werden können. Bei klinisch und ggf. auch elektrophysiologisch gesicherter Diagnose stellt das operative Vorgehen meist eine im Vergleich zum nicht operativen Vorgehen überlegene Therapieoption dar. Hierbei lassen sich insbesondere für das Karpaltunnel-, aber auch für das Kubitaltunnelsyndrom gute Ergebnisse in Bezug auf das Langzeitresultat erreichen. Für die selteneren Kompressionssyndrome, die teilweise umstritten, teilweise uneinheitlich benannt sind, sind weitere kontrollierte Studien notwendig, um evidenzbasierte Therapieempfehlungen aussprechen zu können.

[English] Deep inferior epigastric artery perforator (DIEP) or muscle-sparing transverse rectus abdominis muscle (ms-TRAM) flaps remain the gold standard for autologous reconstruction in post-mastectomy patients, although many women may not be candidates for abdominally based free tissue transfer. In this scenario, there are several other donor site options based from the thigh (transverse and diagonal upper gracilis flaps, profunda artery perforator flap, lateral thigh flap), trunk (lumbar artery perforator flap), and buttock (superior and inferior gluteal artery perforator flaps). This article will provide insight into the history, relevant anatomy, surgical technique and novel applications (neurotization) for alternative flaps in autologous breast reconstruction.Die DIEP- (Deep inferior epigastric Perforator) oder muskelsparende transverse Rectus-abdominis-Myokutan-Lappenplastik (ms-TRAM) gilt als Gold-Standard in der autologen Brustrekonstruktion bei post-Mastektomie Patientinnen. Einige Patientinnen sind aus verschiedenen Gründen keine geeigneten Kandidatinnen für eine Gewebeentnahme am Bauch. In diesen Fällen stehen diverse andere Hebestellen am Oberschenkel (transverse und diagonale myokutane musculus gracilis Lappenplastik, profunda artery perforator Lappenplastik, lateral thigh perforator Lappenplastik), am Stamm (Lumbalarterienperforator-Lappenplastik) und aus der Gesäßregion (superiore und inferiore Glutealarterien und fasziokutane infragluteale Lappenplastik) zu Verfügung. Dieser Artikel gibt einige Einblicke in die Historie, die relevante Anatomie, die chirurgische Technik und neue Anwendungen wie die Neurotisation alternativer Lappenplastiken zur autologen Brustrekonstruktion.

Introduction A need exists to improve the efficiency of clinical trials in burn care. The objective of this study was to validate “Persistent Organ Dysfunction” plus death as endpoint in burn patients and to demonstrate its statistical efficiency. Methods This secondary outcome analysis of a dataset from a prospective international multicenter RCT (RE-ENERGIZE) included patients with burned total body surface area >20% and a 6-month follow-up. Persistent organ dysfunction was defined as persistence of organ dysfunction with life-supportiing technologies and ICU care. Results In the 539 included patients, the prevalence of 0p p+ pdeath was 40% at day 14 and of 27% at day 28. At both timepoints, survivors with POD (vs. survivors without POD) had a higher mortality rate, longer ICU- and hospital-stays, and a reduced quality of life. POD + death as an endpoint could result in reduced sample size requirements for clinical trials. Detecting a 25% relative risk reduction in 28-day mortality would require a sample size of 4492 patients, whereas 1236 patients would be required were 28-day POD + death used. Conclusions POD + death represents a promising composite outcome measure that may reduce the sample size requirements of clinical trials in severe burns patients. Further validation in larger clinical trials is warranted. Study type Prospective cohort study, level of evidence: II

Adipose stem cells (ASCs) possess the capacity to proliferate, to differentiate into various cells types, and they are able to secrete growth factors. These characteristics are supposed to contribute to their potential for regenerative medicine approaches. In order to advance the therapeutic effects of ASCs, different modulatory procedures have been examined. In this context, the endocannabinoid system (ECS) represents an interesting possibility, since the increased availability of cannabinoids and the underlying molecular pathways of the ECS are of relevance for the development of new regenerative strategies. The effects of the endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG) were investigated on ASC metabolic activity, quantified by PrestoBlue conversion, and cell numbers, evaluated by crystal violet staining. enzyme-linked immunosorbent assay (ELISA) measures were performed to determine cytokine release, and differentiation was assessed by specific labeling techniques. AEA increased the metabolic activity, while 2-AG decreased it in a concentration dependent manner. AEA significantly enhanced OilRed O staining after adipogenic differentiation by over 100%, and both compounds significantly increased cresolphthalein staining after osteogenic differentiation. By contrast, they did not affect sphere diameter or safranin O staining after chondrogenic differentiation. Both substances significantly increased the release of insulin-like growth factor-1 and hepatocyte growth factor, while only AEA enhanced transforming growth factor-β secretion. The results demonstrated that stimulating the ECS exerted significant effects on the biology of ASCs. Exposure to endocannabinoids modulated viability, induced release of regenerative growth factors, and promoted adipogenic and osteogenic differentiation. Our findings could be of specific relevance in ASC based therapies for regenerative medicine.

After peripheral nerve injury, Schwann cells (SCs) are crucially involved in several steps of the subsequent regenerative processes, such as the Wallerian degeneration. They promote lysis and phagocytosis of myelin, secrete numbers of neurotrophic factors and cytokines, and recruit macrophages for a biological debridement. However, nerve injuries with a defect size of >1 cm do not show proper tissue regeneration and require a surgical nerve gap reconstruction. To find a sufficient alternative to the current gold standard-the autologous nerve transplant-several cell-based therapies have been developed and were experimentally investigated. One approach aims on the use of adipose tissue stem cells (ASCs). These are multipotent mesenchymal stromal cells that can differentiate into multiple phenotypes along the mesodermal lineage, such as osteoblasts, chondrocytes, and myocytes. Furthermore, ASCs also possess neurotrophic features, that is, they secrete neurotrophic factors like the nerve growth factor, brain-derived neurotrophic factor, neurotrophin-3, ciliary neurotrophic factor, glial cell-derived neurotrophic factor, and artemin. They can also differentiate into the so-called Schwann cell-like cells (SCLCs). These cells share features with naturally occurring SCs, as they also promote nerve regeneration in the periphery. This review gives a comprehensive overview of the use of ASCs in peripheral nerve regeneration and peripheral nerve tissue engineering both in vitro and in vivo. While the sustainability of differentiation of ASCs to SCLCs in vivo is still questionable, ASCs used with different nerve conduits, such as hydrogels or silk fibers, have been shown to promote nerve regeneration.

The inflammatory sequence is the first phase of wound healing. Macrophages (MPhs) and mesenchymal stromal cells (MSCs) respond to an inflammatory microenvironment by adapting their functional activity, which polarizes them into the pro-inflammatory phenotypes M1 and MSC1. Prolongation of the inflammatory phase results in the formation of chronic wounds. The endocannabinoid system (ECS) possesses immunomodulatory properties that may impede this cellular phenotypic switch. We investigated the immunosuppressive influence of the endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG) on the M1 and MSC1 cytokine secretion. Lipopolysaccharides (LPS) were used as inflammagen to stimulate MPhs and MSCs. Both inflammatory phenotypes were co-exposed to AEA or 2-AG, the specific cannabinoid receptor CB2 agonist JWH-133 served as reference. The inflammatory responses were detected by CD80/163 immuno-labelling and by ELISA measures of secreted IL-6, IL-8, MIF, TNF-α, TGF-β, and VEGF. M1 cells were found positive for CD80 expression and secreted less IL-6 and IL-8 than MSC1 cells, while both cell types produced similar amounts of MIF. TNF-α release was increased by M1, and growth factors were secreted by MSC1, only. Cannabinoid receptor ligands efficiently decreased the inflammatory response of M1, while their impact was less pronounced in MSC1. The ECS down-regulated the inflammatory responses of MPhs and MSCs by decreasing the cytokine release upon LPS treatment, while CB2 appeared to be of particular importance. Hence, stimulating the ECS by manipulation of endo- or use of exogenous cannabinoids in vivo may constitute a potent therapeutic option against inflammatory disorders.

Zusammenfassung Hintergrund Seit 2015/16 werden Forschungsanträge aus Sektionen, Abteilungen und Kliniken für Plastische Chirurgie an den Universitätskliniken Deutschlands durch die Deutsche Gesellschaft der Plastischen, Rekonstruktiven und Ästhetischen Chirurgen (DGPRÄC) gesammelt, ausgewertet und 2-jährlich veröffentlicht. Ziel ist es, dadurch die Forschungsleistung der Plastischen Chirurgen in Deutschland öffentlich sichtbar zu machen, um eine Stärkung der akademischen Forschungsstruktur in Deutschland zu erreichen. Material und Methoden Die Leiter der universitären Einrichtungen wurden über den Verteiler der DGPRÄC kontaktiert und um Mitteilung der beantragten, in Begutachtung befindlichen, abgelehnten und geförderten Projekte jeglicher öffentlicher, nicht-öffentlicher, industrieller oder anderer Förderinstitute in die eigens dafür erstellte online Datenbank gebeten: https://docs.google.com/forms/d/e/1FAIpQLSe6F5xmTyw-k7VKJx_2jkPA4LBXsA0sgBGMrC3rx_4bHj6uzQ/viewform?usp=sf_link. Zusätzlich wurden Anträge über die öffentliche Datenbank der Deutschen Forschungsgemeinschaft (DFG), dem Geförderte Projekte Informationssystem (GEPRIS), identifiziert. Ergebnisse Eine Gesamtzahl von 41 Förderanträgen aus den öffentlichen Förderinstituten DFG, BMBF, BMWi, BMG und EU konnte identifiziert werden. 75,6 % (31/41) der Anträge waren zum Zeitpunkt der Datenerhebung bereits bewilligt, davon waren 77,4 % (24/31) DFG-, 9,7 % (3/31) BMWi-, 6,5 % (2/31) EU- und je 3,2 % (1/31) BMBF- und BMG-Anträge. Das durchschnittliche Fördervolumen entsprach 358 301 Euro. Die bewilligten DFG-Anträge waren in 50,0 % (12/24) der Fälle ausschließlich bzw. unter anderem dem Fachkollegium 205–27 Orthopädie, Unfallchirurgie, rekonstruktive Chirurgie zugeordnet. Schlussfolgerung Mithilfe der vorgelegten Forschungsförderungsberichte des Konvents der leitenden universitär tätigen Plastischen Chirurgen der DGPRÄC erfolgt die Veröffentlichung der exzellenten gemeinschaftlichen akademischen Forschungsleistung in unserem Fachgebiet.

BACKGROUND Adipose-derived stem cells are considered as candidate cells for regenerative plastic surgery. Measures to influence cellular properties and thereby direct their regenerative potential remain elusive. Hyperbaric oxygen therapy-the exposure to 100% oxygen at an increased atmospheric pressure-has been propagated as a noninvasive treatment for a multitude of indications and presents a potential option to condition cells for tissue-engineering purposes. The present study evaluates the effect of hyperbaric oxygen therapy on human adipose-derived stem cells. METHODS Human adipose-derived stem cells from healthy donors were treated with hyperbaric oxygen therapy at 2 and 3 atm. Viability before and after each hyperbaric oxygen therapy, proliferation, expression of surface markers and protein contents of transforming growth factor (TGF)-β, tumor necrosis factor-α, hepatocyte growth factor, and epithelial growth factor in the supernatants of treated adipose-derived stem cells were measured. Lastly, adipogenic, osteogenic, and chondrogenic differentiation with and without use of differentiation-inducing media (i.e., autodifferentiation) was examined. RESULTS Hyperbaric oxygen therapy with 3 atm increased viability, proliferation, and CD34 expression and reduced the CD31/CD34/CD45 adipose-derived stem cell subset and endothelial progenitor cell population. TGF-β levels were significantly decreased after two hyperbaric oxygen therapy sessions in the 2-atm group and decreased after three hyperbaric oxygen therapy sessions in the 3-atm group. Hepatocyte growth factor secretion remained unaltered in all groups. Although the osteogenic and chondrogenic differentiation were not influenced, adipogenic differentiation and autodifferentiation were significantly enhanced, with osteogenic autodifferentiation significantly alleviated by hyperbaric oxygen therapy with 3 atm. CONCLUSION Hyperbaric oxygen therapy with 3 atm increases viability and proliferation of adipose-derived stem cells, alters marker expression and subpopulations, decreases TGF-β secretion, and skews adipose-derived stem cells toward adipogenic differentiation. CLINICAL QUESTION/LEVEL OF EVIDENCE Therapeutic, V.

Background: The macrophage migration inhibitory factor (MIF) has been determined as a cytokine exerting a multitude of effects in inflammation and angiogenesis. Earlier studies have indicated that MIF may also be involved in wound healing and flap surgery. Methods: We investigated the effect of MIF in an excisional wound model in wildtype, Mif-/- and recombinant MIF treated mice. Wound closure rates as well as the macrophage marker Mac-3, the pro-inflammatory cytokine tumor necrosis factor α (TNFα) and the pro-angiogenic factor von Willebrand factor (vWF) were measured. Finally, we used a flap model in Mif-/- and WT mice with an established perfusion gradient to identify MIF's contribution in flap perfusion. Results: In the excision wound model, we found reduced wound healing after MIF injection, whereas Mif deletion improved wound healing. Furthermore, a reduced expression of Mac-3, TNFα and vWF in Mif-/- mice was seen when compared to WT mice. In the flap model, Mif-/- knockout mice showed mitigated flap perfusion with lower hemoglobin content and oxygen saturation as measured by O2C measurements when compared to WT mice. Conclusions: Our data suggest an inhibiting effect of MIF in wound healing with increased inflammation and perfusion. In flaps, by contrast, MIF may contribute to flap vascularization.

Journal of Personalized Medicine 12(3), 442 (2022). doi:10.3390/jpm12030442 special issue: "Special Issue "Plastic and Reconstructive Surgery in Personalized Medicine" / Special Issue Editors: Prof. Dr. Andreas Arkudas, Guest Editor; Prof. Dr. Raymund E. Horch, Guest Editor", Published by MDPI, Basel

Primary myoblasts (Mb) and adipose derived mesenchymal stromal cells (ADSC) can be co-cultured and myogenically differentiated in the process of skeletal muscle tissue engineering. Electrospun composite nanofiber scaffolds represent suitable matrices for tissue engineering of skeletal muscle, combining biocompatibility and stability. Although growth differentiation factor 11 (GDF11) has been proposed as a rejuvenating circulating factor, restoring skeletal muscle function in aging mice, some studies have also described a harming effect of GDF11.Therefore the aim of the study was to analyze the effect of GDF11 on co-cultures of Mb and ADSC on poly-ε-caprolacton (PCL)-collagen I-polyethylene oxide (PEO)-nanofibers.Human Mb were co-cultured with ADSC two-dimensionally (2D) as monolayers or three-dimensionally (3D) on aligned PCL-collagen I-PEO-nanofibers. Differentiation media were either serum-free with or without GDF11, or serum containing as in a conventional differentiation medium. Cell viability was higher after conventional myogenic differentiation compared to serum-free and serum-free + GDF11 differentiation as was creatine kinase activity. Immunofluorescence staining showed myosin heavy chain expression in all groups after 28 days of differentiation. Gene expression of myosin heavy chain (MYH2) increased after serum-free + GDF11 stimulation compared to serum-free stimulation alone. The results of this study show that PCL-collagen I-PEO-nanofibers represent a suitable matrix for 3D myogenic differentiation of Mb and ADSC. In this context, GDF11 seems to promote myogenic differentiation of Mb and ADSC co-cultures compared to serum-free differentiation without any evidence of a harming effect.

Aesthetic plastic surgery 46(5), 2208-2217 (2022). doi:10.1007/s00266-021-02762-x, Published by Springer, New York, NY ; Heidelberg ; Berlin

Cell biochemistry and function (2022). doi:10.1002/cbf.3773, Published by Wiley, New York, NY [u.a.]

Post-mastectomy autologous reconstruction with abdominal tissue has evolved over the past 4 decades and is a common reconstructive modality today. To gain more insight into this evolution, we performed an analysis of the 100 most commonly cited articles focusing on autologous breast reconstruction with transverse rectus abdominis musculocutaneous (TRAM) or deep inferior epigastric perforator (DIEP) flaps. A review of the ISI Web of Knowledge database was performed. Only peer-reviewed articles in English were included for analysis. Articles were ranked by their total citations as well as citation density (citations divided by years since publication). The 100 most cited articles were analyzed by their bibliographic parameters. The 100 most cited articles were published in 12 journals. The highest ranked plastic surgery journal published almost 2/3 of the articles. All articles were published within 23 years and marked the "rising age" of autologous breast reconstruction with TRAM and DIEP flaps. The focus of clinical research changed over this time period and ranged from innovations in surgical technique to analysis of clinical outcomes, comparative analyses with other reconstructive modalities, timing of reconstruction, and preoperative diagnostic workup, as well as cost-effectiveness analyses. This literature review illustrates the dramatic change that has occurred subsequent to introduction of abdominal flaps for breast reconstruction. While the use of abdominal flaps has become widely accepted for breast reconstruction, many questions remain unanswered, thus highlighting the need for ongoing clinical investigation.

Medicina : monthly medical journal of Lithuanian Medical Association 57(5), 400 (2021). doi:10.3390/medicina57050400 special issue: "Special Issue "A History of Burn Care" / Special Issue Ediors: Prof. Dr. Lars P. Kamolz, Guest Editor; Dr. Bernd Hartmann, Co-Guest Editor", Published by Kaunas Univ. of Medicine, Kaunas

Abdominoperineal extirpation (APE) especially for bulky tumours and above all in conjunction with previous radiotherapy is not infrequently followed by perineal wound complications, including intrapelvic abscess formation. According to the literature, delayed and persistent wound healing with recurrent pelvic sepsis can be observed in as many as 25–60% of patients. According to Paun et al. [1] and Milne et al. [2] this is related with complications reported in 40 (82%) patients, with major and minor complications in 19 (39%) and 38 (78%) patients, respectively. These complications may result from large, non-collapsing dead space with poor vascularity of the irradiated surrounding tissue or the use of irradiated skin in the closure. These problems are even more pronounced in far advanced pelvic malignancy or recurrent tumours necessitating extralevator abdominoperineal (APE) excision. The incidence of wound complications is even higher after extralevator APE [3]. To accomplish this, complete or partial removal of all of the pelvic viscera, vessels, muscles, ligaments and part of the pelvic bones may be necessary. As a result, pelvic exenteration is often associated with significant morbidity and even mortality, which may result also from inadequate closure of tissue defects.

Cells : open access journal 10(5), 975 (2021). doi:10.3390/cells10050975 special issue: "Special issue "Cellular mechanisms of bone regeneration" / special issue editors: Björn Behr, guest editor; Levkau Bodo, guest editor", Published by MDPI, Basel

Journal of Personalized Medicine 12(5), 701 (2022). doi:10.3390/jpm12050701 special issue: "Special Issue "Plastic and Reconstructive Surgery in Personalized Medicine" / Special Issue Editors: Prof. Dr. Andreas Arkudas, Guest Editor; Prof. Dr. Raymund E. Horch, Guest Editor", Published by MDPI, Basel

In western countries, approximately 1 % of individuals are affected by chronic wounds during their lifetime. Due to changing demographics, this incidence will likely increase in the future. Additionally, the high prevalence is accompanied by substantial treatment expenditures. Therefore, it is of global interest to find effective treatment algorithms. In this article, we present up-to-date solutions for treating chronic / difficult to heal and complex wounds by means of plastic and reconstructive surgery. We outline the principles of chronic wounds and how to perform an appropriate diagnosis. Close cooperation and interdisciplinary exchange are important for optimizing treatment. We report the principles of wound debridement and the role of negative pressure wound therapy. Moreover, we discuss the state of the art of defect reconstruction by means of skin grafting, with or without acellular dermal matrices, local tissue transfers and free tissue transfers. In very complex cases, the local macrovascular blood flow is greatly reduced and there are few, if any, recipient vessels for free flap reconstruction. We discuss the role of arteriovenous loops to overcome this problem.

Background: Soft tissue sarcoma (STS) treatment is an interdisciplinary challenge. Along with radio(chemo)therapy, surgery plays the central role in STS treatment. Little is known about the impact of reconstructive surgery on STS, particularly whether reconstructive surgery enhances STS resection success with the usage of flaps. Here, we analyzed the 10-year experience at a university hospital&rsquo, s Comprehensive Cancer Center, focusing on the role of reconstructive surgery. Methods: We performed a retrospective analysis of STS-patients over 10 years. We investigated patient demographics, diagnosis, surgical management, tissue/function reconstruction, complication rates, resection status, local recurrence and survival. Results: Analysis of 290 patients showed an association between clear surgical margin (R0) resections and higher-grade sarcoma in patients with free flaps. Major complications were lower with primary wound closure than with flaps. Comparison of reconstruction techniques showed no significant differences in complication rates. Wound healing was impaired in STS recurrence. The local recurrence risk was over two times higher with primary wound closure than with flaps. Conclusion: Defect reconstructions in STS are reliable and safe. Plastic surgeons should have a permanent place in interdisciplinary surgical STS treatment, with the full armamentarium of reconstruction methods.