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In Bone Tissue Engineering (BTE), autologous bone-regenerative cells are combined with a scaffold for large bone defect treatment (LBDT). Microporous, polylactic acid (PLA) scaffolds showed good healing results in small animals. However, transfer to large animal models is not easily achieved simply by upscaling the design. Increasing diffusion distances have a negative impact on cell survival and nutrition supply, leading to cell death and ultimately implant failure. Here, a novel scaffold architecture was designed to meet all requirements for an advanced bone substitute. Biofunctional, porous subunits in a load-bearing, compression-resistant frame structure characterize this approach. An open, macro- and microporous internal architecture (100 µm–2 mm pores) optimizes conditions for oxygen and nutrient supply to the implant’s inner areas by diffusion. A prototype was 3D-printed applying Fused Filament Fabrication using PLA. After incubation with Saos-2 (Sarcoma osteogenic) cells for 14 days, cell morphology, cell distribution, cell survival (fluorescence microscopy and LDH-based cytotoxicity assay), metabolic activity (MTT test), and osteogenic gene expression were determined. The adherent cells showed colonization properties, proliferation potential, and osteogenic differentiation. The innovative design, with its porous structure, is a promising matrix for cell settlement and proliferation. The modular design allows easy upscaling and offers a solution for LBDT.
Objective: Clostridial gas gangrene (GG) or clostridial myonecrosis is a very rare but life‐threatening necrotizing soft tissue infection (NSTI) caused by anaerobic, spore‐forming, and gas‐producing clostridium subspecies. It is the most rapidly spreading and lethal infection in humans, also affecting muscle tissue. The high mortality, of up to 100%, in clostridial GG is mediated by potent bacterial exotoxins. Necrotizing fasciitis (NF) is an important differential diagnosis, most often caused by group A streptococci, primarily not affecting musculature but the subcutaneous tissue and fascia. In the early stages of the infection, it is difficult to distinguish between GG and NF. Therefore, we compare both infection types, identify relevant differences in initial clinical presentation and later course, and present the results of our patients in a retrospective review.
Methods: Patients diagnosed with GG from 2008 to 2018 in our level one trauma center were identified. Their charts were reviewed retrospectively and data analyzed in terms of demographic information, microbiological and histological results, therapeutic course, outcome, and mortality rates. The laboratory risk indicator for NF (LRINEC) score was applied on the first blood work acquired. Results were compared to those of a second group diagnosed with NF.
Results: Five patients with GG and nine patients with NF were included in the present study. Patients with GG had a mortality rate of 80% compared to 0% in patients with NF. In eight patients with NF, affected limbs could be salvaged; one NF underwent amputation. LRINEC did not show significant differences between the groups; however, C‐reactive protein was significantly increased (P = 0.009) and hemoglobin (Hb) was significantly decreased (P = 0.02) in patients with GG. Interleukin‐6 and procalcitonin levels did not show significant difference. Patients with GG were older (70.2 vs 50 years). Of the isolated bacteria, 86% were sensitive to the initial calculated antibiotic treatment with ampicillin‐sulbactam or imipenem plus metronidazole plus clindamycin.
Conclusion: Both GG and NF need full‐scale surgical, antibiotic, and intensive care treatment, especially within the first days. Among patients with NSTI, those with clostridial GG have a significantly increased mortality risk due to early septic shock caused by clostridial toxins. In the initial stages, clinical differences are hardly detectable. Immediate surgical debridement is the key to successful therapy for NSTI and needs to be performed as early as possible. However, patients should be treated in a center with an experienced interdisciplinary intensive care team based on a predetermined treatment plan.
Purpose: Acute elbow dislocations are complex injuries that predispose to chronic instability and pain. The ideal treatment strategy is part of controversial discussion and evidence-based recommendations for the treatment could not be concluded from the literature. The purpose of the present study was to assess current epidemiological data, injury pattern, and the changing trend for treatment.
Methods: This study presents a retrospective review of 72 patients ≥ 18 years of age who were treated in our level I trauma centre with acute elbow dislocations from 2014 to 2018. The data were acquired by analysis of the institution’s database, and radiological examinations.
Results: The average age of the patients was 48.5 years (range 18–86). The ratio of male to female patients was 1.9:1. A fall onto the outstretched arm (42%) was the most common injury mechanism. By classification, 42% of the elbow dislocations were simple, and 58% complex. A total of 85% of patients underwent surgery including 73% of the simple elbow dislocations due to remaining instability or non-congruency of the reduced elbow. The indication for surgical treatment correlated merely with the grade of instability and displacement, but not with age.
Conclusion: Acute elbow dislocations need identification of the precise injury pattern and instability after reduction of the elbow joint. To achieve a congruent and stable joint, we recommend primary surgical repair as first-line treatment for patients with unstable simple and complex elbow dislocation independent of age.
Introduction: Epoxyeicosatrienoic acids (EETs) are able to enhance angiogenesis and regulate inflammation that is especially important in wound healing under ischemic conditions. Thus, we evaluated the effect of local EET application on ischemic wounds in mice.
Methods: Ischemia was induced by cautherization of two of the three supplying vessels to the mouse ear. Wounding was performed on the ear three days later. Wounds were treated either with 11,12 or 14,15 EET and compared to untreated control and normal wounds. Epithelialization was measured every second day. VEGF, TNF-α, TGF-β, matrix metalloproteinases (MMP), tissue inhibitors of metalloproteinases (TIMP), Ki67, and SDF-1α were evaluated immunohistochemically in wounds on day 3, 6, and 9.
Results: Ischemia delayed wound closure (12.8 days ± 1.9 standard deviation (SD) for ischemia and 8.0 days ± 0.94 SD for control). 11,12 and14,15 EET application ameliorated deteriorated wound healing on ischemic ears (7.6 ± 1.3 SD for 11,12 EET and 9.2 ± 1.4 SD for 14,15 EET). Ischemia did not change VEGF, TNF-α, TGF-β, SDF-1α, TIMP, MMP7 or MMP9 level significantly compared to control. Local application of 11,12 as well as 14,15 EET induced a significant elevation of VEGF, TGF-β, and SDF-1α expression as well as proliferation during the whole phase of wound healing compared to control and ischemia alone.
Conclusion: In summary, EET improve impaired wound healing caused by ischemia as they enhance neovascularization and alter inflammatory response in wounds. Thus elevating lipid mediator level as 11,12 and 14,15 EET in wounds might be a successful strategy for amelioration of deranged wound healing under ischemia.
Introduction: Microsurgery courses, taught external to surgical training programs, are essential for acquiring the high level of technical skill required for clinical proficiency.
Methods: The Frankfurt microsurgery course is a 5-day, intensive course that teaches arterial and venous anastomosis using end-to-end, end-to-side, one-way-up, continuous-suture, and vessel graft techniques. During the course, the instructor records the level of skill (in-course data) achieved by each trainee by assessing anastomosis completion and patency. Demographic information is also collected. Post-course trainees are invited to complete an online survey (post-course data) to get their opinions of the courses’ effectiveness.
Results: The in-course “skill achievement” and post-course “course effectiveness” data are presented below. In-course data: 94.8 and 59.9% of participants completed patent end-to-end arterial and venous anastomoses, respectively, while 85.4% performed a patent end-to-side anastomosis. 96.1 and 57.1% of participants who attempted arterial and venous anastomoses using the one-way-up technique were successful, as were 90.9% of those attempting continuous-suture technique. Patent venous grafts were performed by 54.7% of participants.
Post-course data: All respondents indicated significant improvement of their microsurgical skills after taking the course. 66.7% of respondents considered the full-time presence of the instructor to be the most valuable aspect of the course. All respondents would highly recommend the course to colleagues.
Conclusion: The microcourse significantly increased trainees’ clinical microsurgery skills, confidence, and the number of clinical cases they perform. Of all the anastomosis techniques taught, venous anastomosis and grafting were the most difficult to learn. The presence of a full-time experienced instructor was most important.
Introduction. Cancellous bone is frequently used for filling bone defects in a clinical setting. It provides favourable conditions for regenerative cells such as MSC and early EPC. The combination of MSC and EPC results in superior bone healing in experimental bone healing models. Materials and Methods. We investigated the influence of osteogenic culture conditions on the endothelial properties of early EPC and the osteogenic properties of MSC when cocultured on cancellous bone. Additionally, cell adhesion, metabolic activity, and differentiation were assessed 2, 6, and 10 days after seeding.
Results. The number of adhering EPC and MSC decreased over time; however the cells remained metabolically active over the 10-day measurement period. In spite of a decline of lineage specific markers, cells maintained their differentiation to a reduced level. Osteogenic stimulation of EPC caused a decline but not abolishment of endothelial characteristics and did not induce osteogenic gene expression. Osteogenic stimulation of MSC significantly increased their metabolic activity whereas collagen-1α and alkaline phosphatase gene expressions declined. When cocultured with EPC, MSC’s collagen-1α gene expression increased significantly. Conclusion. EPC and MSC can be cocultured in vitro on cancellous bone under osteogenic conditions, and coculturing EPC with MSC stabilizes the latter’s collagen-1α gene expression.
Delayed wound repair in sepsis is associated with reduced local pro-inflammatory cytokine expression
(2013)
Sepsis is one of the main causes for morbidity and mortality in hospitalized patients. Moreover, sepsis associated complications involving impaired wound healing are common. Septic patients often require surgical interventions that in-turn may lead to further complications caused by impaired wound healing. We established a mouse model to the study delayed wound healing during sepsis distant to the septic focus point. For this reason cecal ligation and puncture (CLP) was combined with the creation of a superficial wound on the mouse ear. Control animals received the same procedure without CPL. Epithelialization was measured every second day by direct microscopic visualization up to complete closure of the wound. As interplay of TNF-α, TGF-β, matrix metalloproteinases (MMP), and tissue inhibitors of metalloproteinases (TIMP) is important in wound healing in general, TNF-α, TGF-β, MMP7, and TIMP1 were assessed immunohistochemical in samples of wounded ears harvested on days 2, 6, 10 and 16 after wounding. After induction of sepsis, animals showed a significant delay in wound epithelialization from day 2 to 12 compared to control animals. Complete wound healing was attained after mean 12.2± standard deviation (SD) 3.0 days in septic animals compared to 8.7± SD 1.7 days in the control group. Septic animals showed a significant reduction in local pro-inflammatory cytokine level of TNF-α on day 2 and day 6 as well as a reduced expression of TGF-β on day 2 in wounds. A significant lower expression of MMP7 as well as TIMP1 was also observed on day 2 after wounding. The induction of sepsis impairs wound healing distant to the septic focus point. We could demonstrate that expression of important cytokines for wound repair is deregulated after induction of sepsis. Thus restoring normal cytokine response locally in wounds could be a good strategy to enhance wound repair in sepsis.
Meeting abstract : Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2012), 23.10.-26.10.2012, Berlin.
Fragestellung: Die Behandlung langstreckiger Knochendefekte ist eine große Herausforderung. Die Masquelet-Technik zur Behandlung solcher Defekte ist eine zweizeitige Operationstechnik. Zuerst erfolgt die Insertion eines PMMA (Polymethylmethacrylat)-Zementspacers in den Knochendefekt, der die Bildung einer Membran induziert. Diese Membran enthält Wachstumsfaktoren und regenerative Zellen, die möglicherweise die Knochenheilung unterstützen. Nach einigen Wochen wird der Zementspacer entfernt und der induzierte Membranschlauch mit Beckenkammspongiosa aufgefüllt. Im weiteren Verlauf kommt es zu einer kompletten Knochenheilung. Ziele dieser Untersuchung waren die Etablierung der Masquelettechnik am Rattenmodell und die Definition eines Zeitpunkts, an welchem die Membran eine ausreichende Festigkeit sowie einen signifikanten Gehalt von Vorläuferzellen aufweist.
Methodik: Nach Genehmigung der Experimente wurden die Femura von 24 männlichen SD-Ratten osteotomiert. Die Lücke (10 mm) wurde mit PMMA-Zement aufgefüllt und mittels Miniplatte stabilisiert. Parallel wurden den Versuchstieren gleich große PMMA-Spacer subcutan unter die Rückenhaut implantiert. Nach 2, 4, bzw. 6 Wochen (W) erfolgte die Entnahme der Membranen. Ein Teil der Membran wurde für (immun)histologische Untersuchungen aufbereitet (CD34, vWF, van Giesson), ein Teil für die in vitro Kultur. Auswachsende Vorläuferzellen in vitro wurden über CD34 und STRO-1-Färbung nachgewiesen. Statistik: Mediane, Kruskal-Wallis-Test, p<0,05 ist signifikant.
Ergebnisse und Schlussfolgerungen: Im zeitlichen Verlauf nahmen die Vaskularisierung (vWF-positive Fläche [%]: 2 W: 1,8; 4 W:1.6 vs 6 W: 6,4), die Dicke der Membran ([µm]: 2 W: 350 vs 4W: 517, 6 W: 592) und der Bindegewebsanteil ([µm]: 2W: 201 vs 4W: 324, 6W: 404) signifikant zu. Der Hauptanteil elastischer Fasern war auf der dem Zement zugewandten Seite, Vaskularisierung war eher auf der Weichteil zugewandten Seite zu finden. Der Anteil CD34 positiver Zellen nahm signifikant ab (2W: 5%, 4 W: 4% vs 6 W: 1%). Auswachsende STRO-1 positive Zellen konnten nur in zweiwöchigen Membranen nachgewiesen werden. Ältere Membranen wiesen einen zunehmenden Anteil seneszenter Zellen auf. Subcutan induzierte Membranen waren vergleichbar, wiesen jedoch tendentiell eine geringere Dicke und keine STRO-1 positiven Zellen auf.
Mit dieser Studie wurde erstmalig die Induktion einer Membran nach Masquelet im Rattenmodell etabliert. Es konnte nachgewiesen werden, dass der strukturelle Aufbau sowie die zellulären Komponenten zeitlichen Änderungen unterliegen und der Ort der Induktion Einfluss auf die zellulären Komponenten der Membran hat. Junge Membranen (2W) enthielten CD34 und STRO-1 positive Zellen. 4W-Membranen enthielten nur CD34 positive Zellen wiesen aber einen signifikanten Bindegewebsanteil auf, der für eine erhöhte mechanische Stabilität spricht. Ob 2 bzw. 4 Wochen alte Membranen den Knochenheilungsprozess fördern, muss in weiterführenden Studien untersucht werden.
Meeting Abstract (DGU 2003) 67. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie 89. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie 44. Tagung des Berufsverbandes der Fachärzte für Orthopädie Fragestellung Ziel dieser prospektiven Untersuchung ist die Analyse der Funktion und des Outcomes nach distaler Radiusfraktur in Abhängigkeit von Frakturtyp, Therapieform und Begeleitverletzungen. Berücksichtigt wurden diesbezüglich insbesondere auch neuere Implantate wie die volaren winkelstabilen Titanplatten und dorsale low profile Implantate. Methodik Innerhalb von 2 Jahren (01/01 bis 12/02) wurden insgesamt 150 Radiusfrakturen bei 145 Patienten (82 Frauen; 63 Männer) mit einem Durchschnittsalter von 51,8 (17-93) Jahren operativ versorgt. Die operative Versorgung erfolgte in 56,7 % der Fälle mittels volarer Plattenosteosynthese, davon wurde bei 60 % eine winkelstabile Platte eingesetzt. Die übrigen Frakturen wurden durch eine dorsale Platte (8%) bzw. durch Materialkombination Spickdraht/Schrauben und/oder Fixateur externe stabilisiert. Die radiologische und klinische Nachuntersuchung erfolgt frühestens 1 Jahr nach operativer Versorgung. Zusätzlich wird anhand eines Fragebogens der DASH - Score bestimmt. Ergebnisse Nach der AO-Klassifikation fanden sich in 47,7 % Typ A-, 8,6% Typ B- und 55,6% Typ C-Frakturen. Dabei fand sich bei 53,1 % eine relevante Begleitverletzung (Bandverletzungen 14,3 %; Handwurzelfrakturen 3,9 %; distale Ulnafrakturen 10,4%; TFC/Proc. styloideus ulnae 70,1%). Von den 25 bisher untersuchten Patienten (15 Frauen, 10 Männer; Durchschnittsalter: 55,3 Jahre; NU nach: 14 Monaten) waren 32% Typ A-, 20% Typ B- u. 48% Typ C-Frakturen. Die Greifkraft betrug 87,7 % und das Bewegungsausmaß 83,6 % im Vergleich zur Gegenseite. Der durchschnittliche standardisierte DASH-Score betrug 22,6 Punkte (0: optimale Funktion). Bei den mit volarer Platte stabilisierten C-Frakturen (9 der nachuntersuchten Patienten) fand sich ein DASH-Score von 41 Punkten. Die Greifkraft betrug 67,5% und das Bewegungsausmaß 79,6% im Vergleich zur Gegenseite. Bisher konnte weder bei der konventionellen, noch der winkelstabilen Plattenosteosynthese ein radiologischer Korrekturverlust nachgewiesen werden. Bei den Frakturen ohne lokale Begleitverletzungen waren Greifkraft (91% vs. 79,8%), Bewegungsausmaß (89,5% vs. 83,4%) und DASH-Score (16,8 vs. 26,1) besser als bei den Frakturen mit Begleitverletzungen. Schlussfolgerung Bei korrekter Reposition und Stabilisierung, wird der Outcome nach distaler Radiusfraktur neben dem Frakturtyp wesentlich durch die Begleitverletzung mitbestimmt. Daraus resultiert dass eine Verbesserung nur durch eine Optimierung der Therapie der Begleitverletzungen erreichbar ist.