Is there an impact of a video-based patient informed consent in elective hand surgery?

BACKGROUND: Patient informed consent is a crucial subject in preoperative care of patients before elective hand surgery, ensuring that patients have the necessary information and a comprehensive understanding to make autonomous decisions. The use of video-based informed consent systems is an innovative concept to enhance the consent process with multimedia tools. In addition to the conventional process, mostly relying on verbal communication and written documents, the video-based approach aims to present information in a standardized and visually appealing format. METHODS: In this study, 33 patients were asked to watch a video on a tablet about the planned elective hand surgery after a conventional pre-treatment consultation including informed consent throughout verbal explanations and paper forms by an attending physician or resident. All patients were asked to complete a questionnaire after watching the video. RESULTS: An overwhelming majority of participants, specifically 97.0%, stated that the video improved their understanding of the upcoming surgery. 90.9% of the participant would refer the video to other patients undergoing elective hand surgery, while 72.7% of participants indicated that they would have appreciated the opportunity to view an informational video before undergoing different types of surgeries in the past. CONCLUSION: The use of a video-based patient information system in elective hand surgery had a positive impact on patient education and satisfaction with the informed consent process. Therefore, it is a powerful tool in preoperative management to guarantee a standardized and educative informed consent.

Prospective analysis of grip strength and load distribution after surgical treatment of common diseases of the hand with novel's manugraphy® system.

BACKGROUND: Carpal tunnel syndrome, A1 annular pulley stenosis and Dupuytren's contracture are among the most common conditions of the hand. In this study, we investigated the impact of surgical procedure on hand grip strength and high-resolution spatial load distribution in individuals suffering from those diseases over a follow-up period of one year. MATERIALS AND METHODS: In this prospective study, data of 9 patients with carpal tunnel syndrome, 12 patients with A1 annular pulley stenosis and 7 patients with Dupuytren's contracture were evaluated. Only patients with unilateral disease were included providing the contralateral hand as an intra-individual control. Grip strength was measured with cylindrical instruments in two different sizes with respect to the hand size of the patients. Maximum and average values of grip strength as well as spatial load distribution in each finger, thenar, hypothenar and palm were analyzed. Data of the affected patients were collected preoperatively and 6 weeks, 6 months and 1 year postoperatively. Grip strength and spatial load distribution were compared preoperatively to postoperatively. In addition, DASH score, Levine score, 2-point discrimination and degree of flexion contracture were assessed. RESULTS: The patients with A1 annular pulley stenosis showed a significant increase in grip strength 6 months and one year postoperatively. Patients with carpal tunnel syndrome and Dupuytren's contracture showed no significant difference in grip strength over the course of time. An increase in the percentual grip strength of the thenar in patients with carpal tunnel disease and within the affected finger in A1 annular pulley stenosis was observed over the course of time. The DASH score was significantly lower in all patient cohorts one year postoperatively. CONCLUSION: Surgical procedure in carpal tunnel syndrome, A1 annular ligament stenosis and Dupuytren's contracture improves the functionality of the hand in everyday life. Some areas of the hand seem to compensate other weaker areas in grip strength.

Bilateral free flap breast reconstruction using venous cross-over bypass to contralateral internal mammary artery for salvaging thrombosed arterial anastomosis in unilateral repeated irradiation of the breast: A case report.

Adjuvant radiotherapy in breast cancer patients might enhance complications after autologous breast reconstruction, including thrombosis of the internal mammary artery (IMA) precluding its use as recipient vessel. This case report shows a salvage procedure for thrombosis of the IMA during bilateral autologous breast reconstruction in a 51-year-old patient who had undergone repeated irradiation of the chest wall after Hodgkin's disease and recurrent breast carcinoma of the right side. After mastectomy of the right breast and prophylactic mastectomy of the left breast, the patient desired breast reconstruction with autologous tissue. During simultaneous bilateral breast reconstruction using two deep inferior epigastric perforator (DIEP) flaps anastomosed to the left and right inframammary vessels, arterial anastomosis to the right IMA was not feasible due to arterial thrombosis. A salvage procedure using an interpositional cephalic vein graft as a crossover bypass and a subcutaneous presternal tunnel was used. The inferior epigastric artery of the right DIEP flap was anastomosed to the venous bypass, which was anastomosed to the contralateral IMA. Both flaps healed without any complications during the postoperative course and follow up of 6 months. The presented case shows the feasibility of a cross-over venous bypass procedure during bilateral breast reconstruction as salvage maneuver for the arterial anastomosis after repeated radiation of the unilateral breast.

Abdominal Panniculectomy Can Simplify Kidney Transplantation in Obese Patients.

BACKGROUND: Obesity is frequently present in patients suffering from end-stage renal disease (ESRD). However, overweight kidney transplant candidates are a challenge for the transplant surgeon. Obese patients tend to develop a large abdominal panniculus after weight loss creating an area predisposed to wound-healing disorders. Due to concerns about graft survival and postoperative complications after kidney transplantation, obese patients are often refused in this selective patient cohort. The study aimed to analyze the effect of panniculectomies on postoperative complications and transplant candidacy in an interdisciplinary setting. METHODS: A retrospective database review of 10 cases of abdominal panniculectomies performed in patients with ESRD prior to kidney transplantation was conducted. RESULTS: The median body mass index was 35.2 kg/m2 (range 28.5-53.0 kg/m2) at first transplant-assessment versus 31.0 kg/m2 (range 28.0-34.4 kg/m2) at panniculectomy, and 31.6 kg/m2 (range 30.3-32.4 kg/m2) at kidney transplantation. We observed no major postoperative complications following panniculectomy and minor wound-healing complications in 2 patients. All aside from 1 patient became active transplant candidates 6 weeks after panniculectomy. No posttransplant wound complications occurred in the transplanted patients. CONCLUSION: Abdominal panniculectomy is feasible in patients suffering ESRD with no major postoperative complications, thus converting previously ineligible patients into kidney transplant candidates. An interdisciplinary approach is advisable in this selective patient cohort.

The influence of K-wire transfixation on proximalization of the first metacarpal after resection suspension interposition arthroplasty.

INTRODUCTION: Osteoarthritis of the first carpometacarpal joint is a common degenerative disease and surgical treatment includes resection suspension interposition arthroplasty (RSIA) with or without temporary transfixation of the first metacarpal. One major drawback includes proximalization of the first metacarpal during the postoperative course. Specific data comparing different transfixation techniques in this context is sparse. MATERIALS AND METHODS: In this retrospective study, we measured the trapezial space ratio (TSR) in 53 hands before and after RSIA to determine the proximalization of the first metacarpal depending on the type of Kirschner (K)-wire transfixation. We, therefore, compared transfixation of the first metacarpal to the scaphoid with one K-wire (1K) to transfixation of the first metacarpal with two K-wires (2K), either to the carpus (2Ka), or to the second metacarpal (2Kb), or to both second metacarpal and carpus (2Kc). RESULTS: While preoperative TSR did not differ between group 1K and 2K (p = 0.507), postoperative TSR was significantly higher in group 2K compared to 1K (p = 0.003). Comparing subgroups, postoperative TSR was significantly higher in group 2Kc than 1K (p = 0.046), while we found no significant difference comparing either group 2Ka or 2Kb to 1K (p = 0.098; p = 0.159). Neither did we find a significant difference within 2K subgroups, comparing group 2Ka and 2Kb (p = 0.834), 2Ka and 2Kc (p = 0.615), or 2Kb and 2Kc (p = 0.555). CONCLUSIONS: The results of our study suggest that transfixation with two K-wires should be preferred to transfixation with one K-wire after RSIA. Specifically, transfixation from first to second metacarpal and from first metacarpal to carpus resulted in least proximalization of the first metacarpal postoperatively.

Autologous Breast Reconstruction with Transverse Rectus Abdominis Musculocutaneous (TRAM) or Deep Inferior Epigastric Perforator (DIEP) Flaps: An Analysis of the 100 Most Cited Articles.

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.

Myogenic differentiation of primary myoblasts and mesenchymal stromal cells under serum-free conditions on PCL-collagen I-nanoscaffolds.

BACKGROUND: The creation of functional skeletal muscle via tissue engineering holds great promise without sacrificing healthy donor tissue. Different cell types have been investigated regarding their myogenic differentiation potential under the influence of various media supplemented with growth factors. Yet, most cell cultures include the use of animal sera, which raises safety concerns and might lead to variances in results. Electrospun nanoscaffolds represent suitable matrices for tissue engineering of skeletal muscle, combining both biocompatibility and stability. We therefore aimed to develop a serum-free myogenic differentiation medium for the co-culture of primary myoblasts (Mb) and mesenchymal stromal cells derived from the bone marrow (BMSC) and adipose tissue (ADSC) on electrospun poly-ε-caprolacton (PCL)-collagen I-nanofibers. RESULTS: Rat Mb were co-cultured with rat BMSC (BMSC/Mb) or ADSC (ADSC/Mb) two-dimensionally (2D) as monolayers or three-dimensionally (3D) on aligned PCL-collagen I-nanofibers. Differentiation media contained either AIM V, AIM V and Ultroser® G, DMEM/Ham's F12 and Ultroser® G, or donor horse serum (DHS) as a conventional differentiation medium. In 2D co-culture groups, highest upregulation of myogenic markers could be induced by serum-free medium containing DMEM/Ham's F12 and Ultroser® G (group 3) after 7 days. Alpha actinin skeletal muscle 2 (ACTN2) was upregulated 3.3-fold for ADSC/Mb and 1.7-fold for BMSC/Mb after myogenic induction by group 3 serum-free medium when compared to stimulation with DHS. Myogenin (MYOG) was upregulated 5.2-fold in ADSC/Mb and 2.1-fold in BMSC/Mb. On PCL-collagen I-nanoscaffolds, ADSC showed a higher cell viability compared to BMSC in co-culture with Mb. Myosin heavy chain 2, ACTN2, and MYOG as late myogenic markers, showed higher gene expression after long term stimulation with DHS compared to serum-free stimulation, especially in BMSC/Mb co-cultures. Immunocytochemical staining with myosin heavy chain verified the presence of a contractile apparatus under both serum free and standard differentiation conditions. CONCLUSIONS: In this study, we were able to myogenically differentiate mesenchymal stromal cells with myoblasts on PCL-collagen I-nanoscaffolds in a serum-free medium. Our results show that this setting can be used for skeletal muscle tissue engineering, applicable to future clinical applications since no xenogenous substances were used.

Force distribution of a cylindrical grip differs between dominant and nondominant hand in healthy subjects.

INTRODUCTION: Grip strength and load distribution of the hand are important parameters for evaluating hand function. The purpose of this study was to analyze and compare grip force and load distribution of dominant and nondominant hands in right-handed healthy subjects. METHODS: Gripping measurements were performed on 40 healthy right-handed subjects using a cylindrical gripping device. Two different cylinders with circumferences of 150 mm (small cylinder) and 200 mm (large cylinder), respectively, were used for the measurements. Subjects were assigned to either the small or the large cylinder with respect to their hand size. Maximum and mean force applied during three intervals of gripping as well as the percent contribution of each digit, thenar, and hypothenar in relation to the total load applied were acquired. Values of dominant and nondominant hands were compared. RESULTS: Percent contribution of mean grip strength differed for the thumb (p = 0.007), ring finger (p < 0.001), little finger (p = 0.047), and palm (p < 0.001). Comparing the dominant and nondominant side, the dominant hand showed a lower contribution of the thumb, ring finger, and little finger, but a higher contribution of the palm. When analyzing maximum grip, percent contribution of the small fingers was equal between dominant and nondominant side (p = 0.1). Differences between dominant and nondominant thumb, ring finger, and palm persisted (p = 0.007, p = 0.001, p = 0.005, respectively). No differences could be shown for the index finger, middle finger, thenar, and hypothenar when analyzing both mean and maximum force. DISCUSSION AND CONCLUSION: Percent contribution of the thumb and the fingers to total grip strength differed between dominant and nondominant hands with a change in distribution when assessing maximum grip force. In right-handed subjects, thumb and ring finger have important roles during gripping.

Management of extremely hard-to-heal extremity wounds with severe life-threatening complications.

The introduction of neoadjuvant radiotherapy has allowed limb-preserving surgical treatment in patients with extremity soft tissue sarcoma, and the overall prognosis of this approach is similar to that of limb amputation. The benefits of this treatment, however, are often accompanied with a higher risk of major complications and blood vessel damage because of radiation-induced inflammation and necrosis of the vessel wall. In particular, it is associated with the rupture of large vessels like the femoral artery and more severe complications of wounds located in the proximal lower extremity. We present a series of four patients with soft tissue sarcoma of the thigh undergoing tumour removal and reconstruction of the defect after neoadjuvant radiotherapy. The post-operative outcome depended on the total dose of radiation used as well as the closing technique of the resulting wound. Major wound complications occurred when the irradiated skin was closed directly over the resection cavity or when local skin flaps were used. In one case, severe radiation-induced life-threatening multiple bleeding events occurred, which led to multiple flap failures. Even if the skin cover is not a problem, we propose a combined interdisciplinary approach involving immediate plastic surgical transfer of healthy, well-vascularised tissue into a defect resulting from oncological resection of sarcoma of the lower extremity following neoadjuvant radiotherapy in order to avoid secondary wound breakdown and severe bleeding complications.

Application of Near Infrared Spectroscopy to Enhance Safety and Individualize Distraction of Severely Contracted Joints in Far-Advanced Dupuytren's Disease.

Background: Slow distraction of contracted joints is a well-established treatment in far-advanced stages of Dupuytren's disease (DD). To assess finger perfusion and avoid malperfusion, we studied near infrared spectroscopy (NIRS) to evaluate the maximum extent of distraction that would not harm microcirculation to the finger. This technique also allows an optimized treatment in accordance with sufficient blood perfusion during distraction. Methods: Eligible patients with stage IV finger contractures who needed treatment for Dupuytren's contracture were included and prospectively investigated. The operation was performed with local anaesthesia. First, the Dupuytren strand of the treated finger was dissected in the palm to allow distraction. Under X-ray control, the distraction device was applied. Then, slow distraction of the treated joint was performed to evaluate the finger perfusion. To assess perfusion of the treated finger, NIRS was used to measure tissue oxygen saturation. If impaired finger perfusion was detected, traction was reduced until sufficient oxygen levels and perfusion patterns were reestablished. Results: NIRS was performed after application of the distraction device in seven cases. We treated six male and one female patient (mean age 70 years, range 51-80 years). Rapid distraction resulted in malperfusion of the treated fingers. Using NIRS proved to render reliable and reproducible information on finger perfusion and oxygenation in all seven patients. Conclusions: Application of NIRS enhances safety in the treatment of far-advanced DD finger contractures with an external skeletal distraction device. It is non-invasive, reproducible, easy to use and allows for an individualized adapted distraction velocity.

Vein Visualization With a Near Infrared Imaging Device and Its Impact on Students' and Nurses' Skills in an Academic Teaching University Hospital.

Venipuncture for blood collection is frequently delegated to medical or nursing students, while their individual skills depend on the quality of teaching. The aim of this study was to evaluate the use of a near infrared imaging (NIR) system on the visualization of veins and its potential benefit for the education of medical personnel. Participants answered a questionnaire following standardized venipuncture for blood sampling with the help of an NIR device. Vein visibility with the NIR device and its ability to facilitate venipuncture were examined. Visibility of veins was significantly better with the NIR, and its direction was clearly delineated. Sixty-nine percent of the participants stated that they felt more secure with venipuncture after using the NIR device. Patients' individual factors limited the visibility of veins. The adjuvant use of an NIR system for venipuncture improves participants' subjective skills through visualization of veins and their direction.

The Impact of Technical Innovations and Donor-Site Mesh Repair on Autologous Abdominal-Based Breast Reconstruction-A Retrospective Analysis.

Background: The aim of this study was to examine the potential benefit that may be achieved through the introduction of technical innovations and the incorporation of mesh for fascial donor site closure in uni- and bilateral autologous breast reconstruction with abdominal tissue. Methods: A retrospective single-center review of all breast reconstructions with a DIEP or MS-TRAM flap between January 2004 and December 2019 was performed. Donor and recipient site complications and operation times were evaluated before and after the implementation of coupler anastomoses, preoperative computed tomography angiography (CTA), indocyanine green (ICG) angiography, and the inclusion of mesh in donor site repair. Results: A total of 396 patients were included, accounting for 447 flaps. Operation time was significantly shorter in unilateral reconstructions after the implementation of CTA (p < 0.0001). ICG angiography significantly reduced the rates of partial flap loss (p = 0.02) and wound healing disorders (p = 0.02). For unilateral reconstructions, abdominal bulging or hernia was observed more often in MS1-TRAM flaps without synthetic mesh repair (p = 0.001), whereas conservatively treated seroma developed more frequently after mesh implantation (p = 0.03). Conclusions: Recent technological advancements developed over the past few decades have made a substantial impact on decreasing surgical duration and enhancing procedure safety.

[Postbariatric plastic surgery for body reconstruction]. / Postbariatrische plastische Körperrekonstruktionen.

Massive weight loss following bariatric surgery is often accompanied by functional impairments due to the resulting excess skin and soft tissues. To achieve both functional reconstruction and restoration of the body silhouette, it is imperative to undergo body contouring surgery involving the strategic transposition of tissues. Several surgical techniques are available for the affected body regions and their application for treatment is determined by the unique circumstances specific to each patient. When conducted by skilled practitioners, postbariatric body reconstruction can be executed safely, leading to outcomes that are both functionally and esthetically satisfying, ultimately contributing to an enhanced quality of life for patients. This article provides the fundamental principles for patient selection, surgical preparation, treatment planning, surgical techniques and the postoperative care following bariatric surgery.

[Long-Term Outcome of Digital Defect Reconstruction using Cross-Finger Flaps]. / Langzeitergebnisse nach Rekonstruktion von Fingerdefekten mittels Cross-Finger-Lappenplastik.

INTRODUCTION: Although multiple advances have been made in finger defect reconstruction, cross-finger flaps remain an important reconstructive tool. However, data on long-term results are scarce in the literature. This study aimed to assess the clinical and subjective long-term outcomes of patients who underwent cross-finger flap reconstruction for palmar digital and fingertip defects. PATIENTS AND METHODS: Between January 2003 and July 2022, 35 patients (31 male, 4 female, mean age: 59.0 years±20.1) were screened and included in the study. The data were obtained through a clinical examination, a Quick-DASH score and a self-designed questionnaire. Clinical outcomes were assessed by evaluating the range of motion (ROM) of the reconstructed finger and the donor finger compared with the contralateral uninjured hand. In addition to ROM, a static two-point separation test was performed to assess the sensory function of the reconstructed finger. The follow-up period was between 1 year and 19 years (mean: 12.6 years±6.1). RESULTS: There was no significant difference in terms of ROM between the reconstructed finger and the donor finger compared with the contralateral uninjured hand. All patients reported normal discrimination between sharp and blunt objects. However, there was a significant difference in two-point discrimination between the reconstructed finger and the healthy contralateral finger (p<0.05). The average Quick-DASH score was 5.1 points. Satisfaction with the functional outcome in terms of mobility and load-bearing capacity of the cross-finger flap averaged 8.1 out of 10 points. Satisfaction with the aesthetic outcome of the reconstructed finger averaged 7.7 out of 10 points. In 4 cases, persistent pain was reported when the reconstructed finger was under stress. No cases of pain at rest were reported. CONCLUSION: In the long run, cross-finger flaps are a safe and effective reconstructive procedure for covering defects in palmar injuries of the finger and fingertip amputation. They represent a simple, reliable, long-lasting reconstructive technique. The necessary temporary iatrogenic syndactyly does not lead to long-term limitations in the range of motion.

Schwann Cells Do Not Promote Myogenic Differentiation in the EPI Loop Model.

In skeletal muscle tissue engineering, innervation and vascularization play an essential role in the establishment of functional skeletal muscle. For adequate three-dimensional assembly, biocompatible aligned nanofibers are beneficial as matrices for cell seeding. The aim of this study was to analyze the impact of Schwann cells (SC) on myoblast (Mb) and adipogenic mesenchymal stromal cell (ADSC) cocultures on poly-ɛ-caprolactone (PCL)-collagen I-nanofibers in vivo. Human Mb/ADSC cocultures, as well as Mb/ADSC/SC cocultures, were seeded onto PCL-collagen I-nanofiber scaffolds and implanted into the innervated arteriovenous loop model (EPI loop model) of immunodeficient rats for 4 weeks. Histological staining and gene expression were used to compare their capacity for vascularization, immunological response, myogenic differentiation, and innervation. After 4 weeks, both Mb/ADSC and Mb/ADSC/SC coculture systems showed similar amounts and distribution of vascularization, as well as immunological activity. Myogenic differentiation could be observed in both groups through histological staining (desmin, myosin heavy chain) and gene expression (MYOD, MYH3, ACTA1) without significant difference between groups. Expression of CHRNB and LAMB2 also implied neuromuscular junction formation. Our study suggests that the addition of SC did not significantly impact myogenesis and innervation in this model. The implanted motor nerve branch may have played a more significant role than the presence of SC.

Analysis of laboratory markers in body contouring procedures after bariatric surgery does not indicate particular risks for perioperative complications.

BACKGROUND: Body contouring surgery after massive weight loss is associated with different risk factors. Wound healing disorders and seromas commonly occur postoperatively. Bariatric interventions lead to massive weight loss with excess skin and soft tissue. In this study, perioperatively collected laboratory markers of this special patient population were analyzed. METHODS: Fifty-nine patients were analyzed retrospectively regarding bariatric surgery, weight loss, body contouring surgery, laboratory markers, and complication rates. RESULTS: Body contouring surgery (n = 117) was performed in 59 patients. Weight loss was achieved after gastric bypass (40.1%), gastric banding (33.9%), or sleeve gastrectomy (26.0%), with an average of 69.2 kg. The most common body contouring procedure included abdominoplasty (n = 50), followed by thigh lift (n = 29), mammaplasty (n = 19), brachioplasty (n = 14), and upper body lift (n = 5). Analysis of laboratory markers revealed no exceptional and clinically relevant variations. Correlation analysis revealed associations between resection weight, amount of drain fluid, and particular laboratory markers. CONCLUSION: Analysis of perioperative laboratory markers in this special patient population after massive weight loss did not indicate clinically relevant risk factors regardless of the type of bariatric or body contouring surgery. Body contouring surgeries after bariatric interventions prove to be safe and low risk concerning perioperative laboratory markers and postoperative hospitalization.

Imaging in reconstructive microsurgery - current standards and latest trends.

In microsurgery, many different imaging techniques are available in both flap and lymphatic surgery that all come with their own advantages and disadvantages. In flap surgery, CT angiography is considered as the gold standard. Among others, Doppler ultrasound, color Doppler ultrasound, ICG, and smartphone-based thermal cameras are valuable imaging techniques. In lymphatic surgery, photoacoustic imaging, laser tomography, contrast-enhanced magnetic resonance imaging, and high frequency ultrasound stand available to surgeons next to the current standard of lymphoscintigraphy. It is crucial to know the advantages and disadvantages to various techniques and highly adviced to microsurgeons be capable of using a variety of them.

[Complications and their management following axillary, inguinal and iliac lymph node dissection]. / Komplikationen und deren Management nach axillärer, inguinaler und iliakaler Lymphknotendissektion.

Irrespective of numerous technical developments, lymphadenectomy remains a necessary component of surgical tumor therapy. Depending on the extent and anatomical localization, complications associated with the lymph vessels such as lymphoceles, lymphatic fistulas or secondary lymphedema can occur with varying frequency, despite a meticulous dissection technique. Chronic lymph fistulas or lymphoceles often require interventional or surgical procedures. Pedicled or free microsurgical flaps are often required in the case of coexisting wound healing disorders or skin soft tissue defects, especially in an irradiated area. For secondary lymphedema a number of conservative and surgical treatment methods have been established. Adequate guideline-based conservative treatment is the method of first choice. If this does not lead to the desired result, microsurgical reconstructive, deviating or resecting procedures are available.

Perspectives on the Current State of Bioprinted Skin Substitutes for Wound Healing.

Human skin is particularly vulnerable to external damaging influences such as irradiation, extreme temperatures, chemical trauma, and certain systemic diseases, which reduce the skin's capacity for regeneration and restoration and can possibly lead to large-scale skin defects. To restore skin continuity in severe cases, surgical interventions such as the transplantation of autologous tissue are needed. Nevertheless, the coverage of larger skin defects caused by severe third-grade burns or extensive irradiation therapy is limited due to the depletion of uninjured autologous tissue. In such cases, many of the patient's epidermal cells can become available using biofabricated skin grafts, thereby restoring the skin's vital functions. Given the limited availability of autologous skin grafts for restoring integrity in large-scale defects, using bioprinted constructs as skin graft substitutes could offer an encouraging therapeutic alternative to conventional therapies for large-scale wounds, such as the transplantation of autologous tissue. Using layer-by-layer aggregation or volumetric bioprinting, inkjet bioprinting, laser-assisted bioprinting, or extrusion-based bioprinting, skin cells are deposited in a desired pattern. The resulting constructs may be used as skin graft substitutes to accelerate wound healing and reconstitute the physiological functions of the skin. In this review, we aimed to elucidate the current state of bioprinting within the context of skin tissue engineering and introduce and discuss different bioprinting techniques, possible approaches and materials, commonly used cell types, and strategies for graft vascularization for the production of bioprinted constructs for use as skin graft substitutes.

Myogenic differentiation of human myoblasts and Mesenchymal stromal cells under GDF11 on NPoly-ɛ-caprolactone-collagen I-Polyethylene-nanofibers.

BACKGROUND: For the purpose of skeletal muscle engineering, primary myoblasts (Mb) and adipogenic mesenchymal stem cells (ADSC) can be co-cultured and myogenically differentiated. Electrospun composite nanofiber scaffolds represent suitable matrices for tissue engineering of skeletal muscle, combining both 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-caprolactone (PCL)-collagen I-polyethylene oxide (PEO)-nanofibers. RESULTS: 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 myosine heavy chain expression in all groups after 28 days of differentiation without any clear evidence of more or less pronounced expression in either group. Gene expression of myosine heavy chain (MYH2) increased after serum-free + GDF11 stimulation compared to serum-free stimulation alone. CONCLUSIONS: This is the first study analyzing the effect of GDF11 on myogenic differentiation of Mb and ADSC co-cultures under serum-free conditions. 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.