[Locoregional solutions for groin defects : Coverage after vascular surgery]. / Lokoregionale Lösungen bei Leistendefekten : Deckung nach gefäßchirurgischen Eingriffen.

INTRODUCTION: Vascular surgery through a groin incision may be associated with severe wound healing disorders in this sensitive area. There are many options to reconstruct the defect surgically. The choice of surgical reconstruction depends mainly on the individual status of vasculature, which is most often compromised in these patients. There are random pattern flaps, as well as perforator, pedicled flaps or microvascular flaps to choose from. AIM: We give an overview of plastic surgical solutions for groin defects, with a special focus on complex wounds after vascular surgical complications. We discuss advantages and disadvantages of different flaps with two case reports and also show alternatives. PATIENTS AND METHODS: We demonstrate in two cases how the reconstruction of the groin defect was planned, taking into account the vascular status, and why we chose an innovative and seldom-used option in each case. RESULTS: The selected flaps, a pedicled fasciocutaneous ALT propeller flap and a perforator-based, pedicled abdominal advancement flap reconstructed the defects successfully. DISCUSSION: The surgical therapy for the reconstruction of groin defects should be chosen according to the individual vascular status to ensure safe and reliable blood supply. To guarantee the best possible reconstruction and avoid postoperative healing disorders and infections, less common flaps should also be considered.

[Overview and Introduction of a Treatment Concept for Postoperative Care and Mobilisation After Free Flap Transplantation in the Lower Extremity]. / Überblick und Vorstellung eines Behandlungskonzeptes zur postoperativen Therapie und Mobilisation nach freier Lappenplastik an der unteren Extremität.

Introduction: Free flap transplants for soft tissue reconstruction in the lower extremity are associated with a higher rate of complications compared with other areas. Mobilisation and the resulting hydrostatic pressure put strain on the flaps. In general, these effects are countered by slowly increasing hydrostatic pressure with the leg being compressed by elastic bandages. These postoperative regimes are also called dangling procedures or "flap training", but are not scientifically validated and therefore there is no consensus or guideline leading to a standard treatment regime. The goal of our study was to present an overview of currently performed regimes. Material and Methods: We conducted an email survey by sending a questionnaire to departments for plastic and reconstructive surgery in Germany, Austria and Switzerland, which perform free flap transplantations in the lower extremity. The questionnaire ascertained the starting point and the frequency of the dangling procedures, the introduction of weight-bearing on the operated extremity and the incidence of complications occurring during mobilisation. Results: We included 32 departments and compared them by the number of free flap transplantations performed per year. We found a wide variation between the postoperative treatment regimes. In most departments, flap training is started between the 3rd and 7th day after surgery and lasts between 5 and 15 min. The intervals with which flap training intensity is increased are inhomogeneous as well. The time until full weight-bearing is exerted on the operated extremity ranges from day 5 to week 3 postoperatively. Complications due to flap training were reported by one third of the participating departments. Conclusion: Elastic compression and patient mobilisation after free flap procedures in the lower extremity are considered to be very important in reducing complications and in protecting the flap from edema and volume overload. This article demonstrates that there is a wide variety in flap training regimes. It aims to help readers evaluate their own regimes and provides guidance for an individualised patient-oriented regime.

[In Vitro and In Vivo Biocompatibility of a Novel, 3-Dimensional Cellulose Matrix Structure]. / In vitro und in vivo Biokompatibilität einer neuartigen, 3-dimensionalen Cellulose-Matrixstruktur.

BACKGROUND: Biological and physical characteristics of matrices are one essential factor in creating bioartificial tissue. In this study, a new 3-dimensional cellulose matrix (Xellulin(®)) was tested in terms of biocompatibility and applicability for tissue engineering in vitro and in vivo. MATERIALS AND METHODS: The tested matrix Xellulin(®) is a natural hydrological gel-matrix containing bacterial cellulose and water. To evaluate the cell biocompatibilty, cell adherence and proliferation characteristics in vitro, the matrix was cultured with human fibroblasts. Further in vivo studies were carried out by transplanting preadipocytes of 4- to 6-week-old Wistar rats with 3 different conditions: a) Xellulin(®) including 500 000 preadipocytes subcutaneous, b) Xellulin(®) including 500 000 preadipocytes within an in vivo bioreactor chamber, c) Xellulin(®) without cells subcutaneous as control. After explantation on day 14 histomorphological and immunohistochemical evaluations were performed. RESULTS: In vitro study revealed an excellent biocompatibility with good cell adherence of the fibroblasts on the matrix and evidence of cell proliferation and creation of a 3-dimensional cell network. In vivo neocapillarisation could be shown in all groups with evidence of erythrocytes (H/E staining) and endothelial vascular cells (RECA-1-staining). A significantly higher vascular density was shown in vascularised bioreactor group (18.4 vessels/100 000 µm(2) (group b) vs. 8.1 (group a), p<0.05). Cell density was the highest in the vascularised group, but without significant values. No immunogenic reaction to the matrix was noticed. DISCUSSION: The promising in vitro results concerning cell adherence and proliferation on the tested matrix could be confirmed in vivo with an evidence of 3-dimensional neocapillarisation. Cell survival was higher in the vascularised group, but without significance. Long-term tests (28-42 days) need to be carried out to evaluate long-term cell survival and the matrix stability. Furthermore, studies concerning the implementation of the matrix within anatomic structures as well as long-term biocompatibility are needed.

[Training in aesthetic surgery at a university clinic - the "Munich model"]. / Weiterbildung in der ästhetischen Chirurgie an einer Universitätsklinik - Das "Münchner Modell"

BACKGROUND: Aesthetic surgery is regarded as one of the 4 pillars of plastic surgery. To assure safety in this field of surgery, a structured and well guided surgical training is indispensable. However, during the specialist training for plastic and aesthetic surgery, plastic aesthetic interventions are often carried out in low numbers only. Objective of the present study was the development, implementation and evaluation of a new training concept in aesthetic surgery. PATIENTS: Over a period of 2 years, 304 aesthetic operations were performed in the fields of body contouring, breast surgery and facial surgery as an "educational surgery". Educational surgeries were performed by resident surgeons under the guidance of experienced specialists and under favourable financial conditions. As indicator for safety of the interventions, the incidence of complications was recorded and assessed. RESULTS: Out of a total of 304 operations included in the study 47.7% were performed as an educational surgery. In the fields of body contouring and breast surgery, the majority of interventions (51.3% and, respectively, 53%) were carried out as educational surgeries. In aesthetic surgeries of the face only 28.4% were educational surgeries. In 4.9% of all cases complications occurred. The incidences of complications were approximately the same in the educational surgeries (5.5%) and in the surgeries carried out by experienced specialists (4.4%), showing no significant difference. CONCLUSION: The presented training concept aims at ensuring high quality in patient care by structure and quality of surgical training. Our data give evidence that a structured training of residents in the field of aesthetic surgery is possible without loss in quality. We expect that -sufficient surgical education and the associated quality will consequently contribute to keep aesthetic surgeries a domain of plastic surgery and to prevent these procedures from being taken over by other surgical disciplines.

[Autologous fat grafts and supportive enrichment with adipose tissue stromal cells]. / Autologe Fetttransplantation in der Brustchirurgie - Klinische und Experimentelle Konzepte: vom Lipofilling bis zum Fettgewebe Tissue Engineering.

Liposuction is a most common surgical procedure in aesthetic surgery that aims at the local fat reduction. The obtained adipose tissue is currently used as a biocompatible filler. Autologous fat transplantation, also known as lipofilling, has become an attractive treatment method in the field of aesthetic facial surgery and scar tissue reconstruction. Lipofilling may also offer an alternative method to prosthetic breast surgery. Nevertheless, postoperative fat tissue resorption is still a limitiation to lipofilling in breast reconstruction leading to multiple revisions in order to reach the requested clinical outcome. The therapeutic effect of autologous fat grafts does not solely lie in its role as a filler material, but also in its wound healing and angiogenetic properties. The latter is not attributed to the mature adipocytes, but rather to the undifferentiated adipose derived stromal cells (ASC). Thus enrichment of the fat graft with autologous ASC, known as cell-assisted lipotransfer (CAL) may lead to further optimisation of lipofilling concerning fat graft survival. Still aiming to establish the application of autologous fat grafts and ASC in breast reconstruction, there is a necessity for systematic analyses in order to resolve questions regarding the operational technique and qualitative aspects of the ASC manufacturing in accordance with pharmaceutical guidelines and regulations in Germany. Besides, some open questions need to be addressed regarding the ASC differentiation potential in vivo.

[Quo vadis? Breast implants--current trends and new concepts]. / Quo vadis? Brustimplantate--aktuelle Entwicklungen und neue Konzepte.

BACKGROUND: Breast augmentation is one of the most frequent surgical procedures performed by plastic surgeons. Furthermore, in the majority of breast reconstructions implants are still in use. With the focus on surface modifications and biomaterials, the article provides an overview of the latest trends and concepts in increase of implant biocompatibility and reduction of capsular contracture. Because of the recent events regarding PIP® implants, a short report on this topic is presented as well. MATERIALS AND METHODS: The literature was searched for experimental and clinical studies, as well as meta-analysis and reviews, using the databases PubMed, Embase and Cochrane Collaboration. Based on the title, year of publication and abstracts, thematically relevant and recent publications in English or German were selected and full text articles were studied. RESULTS: According to the classification, 4-5 generations of breast implants have been developed since the 1960s. Modifications affected diverse areas including various surface textures as well as coatings with polyurethane or titanium. Some of these changes were able to reduce capsular contracture, however, without resolving the issue sufficiently. Recent experimental studies mostly evaluated different surface coatings with antifibrotic and antibacterial substances. For the local drug release various carrier substances were used. Furthermore, drugs were covalently bonded to the implant surface or applied by surface impregnation. In different approaches biocompatibility could be increased by biomimicry or nanotechnologically modified biomaterials, which could additionally contribute to the reduction of capsular contracture. CONCLUSION: The development of coating technologies for the locally controlled sustained drug release using the implant surface as drug delivery system could potentially enable the local administration of drugs, which were orally delivered in clinical trials, and effectively reduced capsular contracture. This kind of application could potentially minimize the risk of adverse side effects. However, there are still some questions concerning controlled drug release systems for implant surfaces, as well as long-term results and possible side effects of drugs in a continuous local administration to be answered in further studies.

[Calvarial reconstruction by customized bioactive implant]. / Rekonstruktion der Kalvaria durch ein präfabriziertes bioaktives Implantat.

Osseous craniofacial defects are commonly seen problems after operative treatment of craniosynostoses. This case report describes a calvarial reconstruction by means of computer-aided fabrication of a customised implant. Three-dimensional imaging is followed by computer-aided design and fabrication of a medical grade PCL-TCP biodegradable scaffold using the rapid prototyping technology fused deposition modelling (CAD/CAM). After six months the implant was well integrated, no defect area could be palpated any more and a beginning bony consolidation could be detected via CT.

A comparative analysis of scaffold material modifications for load-bearing applications in bone tissue engineering.

To facilitate optimal application of appropriate scaffold architectures for clinical trials, there is a need to compare different scaffold modifications under similar experimental conditions. In this study was assessed the effectiveness of poly-e-caprolactone (PCL) scaffolds fabricated by fused deposition modelling (FDM), with varying material modifications, for the purposes of bone tissue engineering. The incorporation of hydroxyapatite (HA) in PCL scaffolds, as well as precalcification through immersion in a simulated body fluid (SBF) to produce a biomimetic apatite coating on the scaffolds, was assessed. A series of in vitro studies spanning 3 weeks as well as in vivo studies utilizing a subcutaneous nude mouse model were carried out. PCL and HA-PCL scaffolds demonstrated increasing tissue growth extending throughout the implants, as well as superior mechanical strength and mineralization, as evidenced by X-ray imaging after 14 weeks in vivo. No significant difference was found between PCL and HA-PCL scaffolds. Precalcification with SBF did not result in increased osteoconductivity and cell proliferation as previously reported. Conversely, tensile forces exerted by tissue sheets bridging adjacent struts of the PCL scaffold caused flaking of the apatite coating that resulted in impaired cell attachment, growth and mineralization. The results suggest that scaffolds fabricated by FDM may have load-bearing applications.

Peroxynitrite-modified collagen-II induces p38/ERK and NF-kappaB-dependent synthesis of prostaglandin E2 and nitric oxide in chondrogenically differentiated mesenchymal progenitor cells.

OBJECTIVE: Peroxynitrite (ONOO(-)) is formed in the inflamed and degenerating human joint. Peroxynitrite-modified collagen-II (PMC-II) was recently discovered in the serum of patients with osteoarthritis (OA) and rheumatoid arthritis (RA). Therefore we investigated the cellular effects of PMC-II on human mesenchymal progenitor cells (MPCs) as a model of cartilage and cartilage repair cells in the inflamed and degenerating joint. DESIGN: MPCs were isolated from the trabecular bone of patients undergoing reconstructive surgery and were differentiated into a chondrogenic lineage. Cells were exposed to PMC-II and levels of the proinflammatory mediators nitric oxide (*NO) and prostaglandin E(2) (PGE(2)) measured. Levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), phosphorylated mitogen activated protein kinases (MAPKs) and nuclear factor kappa B (NF-kappaB) activation were measured by enzyme linked immunosorbent assay (ELISA) together with specific MAPK and NF-kappaB inhibitors. RESULTS: PMC-II induced ()NO and PGE(2) synthesis through upregulation of iNOS and COX-2 proteins. PMC-II also lead to the phosphorylation of MAPKs, extracellularly regulated kinase 1/2 (ERK1/2) and p38 [but not c-Jun NH(2)-terminal kinase (JNK1/2)] and the activation of proinflammatory transcription factor NF-kappaB. Inhibitors of p38, ERK1/2 and NF-kappaB prevented PMC-II induced ()NO and PGE(2) synthesis, iNOS and COX-2 protein expression and NF-kappaB activation. CONCLUSION: iNOS, COX-2, NF-kappaB and MAPK are known to be activated in the joints of patients with OA and RA. PMC-II induced iNOS and COX-2 synthesis through p38, ERK1/2 and NF-kappaB dependent pathways suggesting a previously unidentified pathway for the synthesis of the proinflammatory mediators, ()NO and PGE(2), further suggesting that inhibitors of these pathways may be therapeutic in the inflamed and degenerating human joint.

Osteogenic induction of human bone marrow-derived mesenchymal progenitor cells in novel synthetic polymer-hydrogel matrices.

The aim of this project was to investigate the in vitro osteogenic potential of human mesenchymal progenitor cells in novel matrix architectures built by means of a three-dimensional bioresorbable synthetic framework in combination with a hydrogel. Human mesenchymal progenitor cells (hMPCs) were isolated from a human bone marrow aspirate by gradient centrifugation. Before in vitro engineering of scaffold-hMPC constructs, the adipogenic and osteogenic differentiation potential was demonstrated by staining of neutral lipids and induction of bone-specific proteins, respectively. After expansion in monolayer cultures, the cells were enzymatically detached and then seeded in combination with a hydrogel into polycaprolactone (PCL) and polycaprolactone-hydroxyapatite (PCL-HA) frameworks. This scaffold design concept is characterized by novel matrix architecture, good mechanical properties, and slow degradation kinetics of the framework and a biomimetic milieu for cell delivery and proliferation. To induce osteogenic differentiation, the specimens were cultured in an osteogenic cell culture medium and were maintained in vitro for 6 weeks. Cellular distribution and viability within three-dimensional hMPC bone grafts were documented by scanning electron microscopy, cell metabolism assays, and confocal laser microscopy. Secretion of the osteogenic marker molecules type I procollagen and osteocalcin was analyzed by semiquantitative immunocytochemistry assays. Alkaline phosphatase activity was visualized by p-nitrophenyl phosphate substrate reaction. During osteogenic stimulation, hMPCs proliferated toward and onto the PCL and PCL-HA scaffold surfaces and metabolic activity increased, reaching a plateau by day 15. The temporal pattern of bone-related marker molecules produced by in vitro tissue-engineered scaffold-cell constructs revealed that hMPCs differentiated better within the biomimetic matrix architecture along the osteogenic lineage.

Evaluation of ultra-thin poly(epsilon-caprolactone) films for tissue-engineered skin.

Various natural and synthetic polymeric materials have been used as scaffold matrices for tissue-engineered skin. However, the commercially available skin replacement products pose problems of poor mechanical properties and immunological rejection. We have thus developed a film of 5 microm thickness, via biaxial stretching of poly(epsilon-caprolactone) (PCL), as a potential matrix for living skin replacements. The aim of this study was to evaluate the feasibility of using biaxially stretched PCL films as matrices for culturing human dermal fibroblasts. For this purpose, we cultured human dermal fibroblasts for 7 days on the films. Glass cover slips and polyurethane (PU) sheets were used as controls. The data from phase contrast light, confocal laser, and scanning electron microscopy suggested that biaxially stretched PCL films support the attachment and proliferation of human dermal fibroblasts. Thymidine-labeling results showed quantitatively that cell proliferation on the PCL films was superior to that on the PU samples. These results indicated that biaxially stretched PCL films supported the growth of human dermal fibroblasts and might have potential to be applied in tissue engineering a dermal equivalent or skin graft.