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Regeneration of large bone defects is a major objective in trauma surgery. Bone marrow mononuclear cell (BMC)-supported bone healing was shown to be efficient after immobilization on a scaffold. We hypothesized that fibrous demineralized bone matrix (DBM) in various forms with BMCs is superior to granular DBM. A total of 65 male SD rats were assigned to five treatment groups: syngenic cancellous bone (SCB), fibrous demineralized bone matrix (f-DBM), fibrous demineralized bone matrix densely packed (f-DBM 120%), DBM granules (GDBM) and DBM granules 5% calcium phosphate (GDBM5%Ca2+). BMCs from donor rats were combined with different scaffolds and placed into 5 mm femoral bone defects. After 8 weeks, bone mineral density (BMD), biomechanical stability and histology were assessed. Similar biomechanical properties of f-DBM and SCB defects were observed. Similar bone and cartilage formation was found in all groups, but a significantly bigger residual defect size was found in GDBM. High bone healing scores were found in f-DBM (25) and SCB (25). The application of DBM in fiber form combined with the application of BMCs shows promising results comparable to the gold standard, syngenic cancellous bone. Denser packing of fibers or higher amount of calcium phosphate has no positive effect.
Bone marrow mononuclear cells (BMCs) are suitable for bone tissue engineering. Comparative data regarding the needs of BMC for the adhesion on biomaterials and biocompatibility to various biomaterials are lacking to a large extent. Therefore, we evaluated whether a surface coating would enhance BMC adhesion and analyze the biocompatibility of three different kinds of biomaterials. BMCs were purified from human bone marrow aspirate samples. Beta tricalcium phosphate (β-TCP, without coating or coated with fibronectin or human plasma), demineralized bone matrix (DBM), and bovine cancellous bone (BS) were assessed. Seeding efficacy on β-TCP was 95% regardless of the surface coating. BMC demonstrated a significantly increased initial adhesion on DBM and β-TCP compared to BS. On day 14, metabolic activity was significantly increased in BMC seeded on DBM in comparison to BMC seeded on BS. Likewise increased VEGF-synthesis was observed on day 2 in BMC seeded on DBM when compared to BMC seeded on BS. The seeding efficacy of BMC on uncoated biomaterials is generally high although there are differences between these biomaterials. Beta-TCP and DBM were similar and both superior to BS, suggesting either as suitable materials for spatial restriction of BMC used for regenerative medicine purposes in vivo.
Bei Knochendefekten kritischer Größe ist es notwendig, den Knochen bei der Heilung zu unterstützen. Der derzeitige Goldstandard bei der Behandlung von critical size defects ist die Entnahme von autologem Knochen aus dem Beckenkamm, dies ist jedoch mit Nachteilen wie Entnahmemorbidität und Limitierung der entnehmbaren Menge vergesellschaftet. Das Knochen tissue engineering, bei welchem regenerative Zellen mit einem Knochenersatzmaterial kombiniert werden, könnte eine vielversprechende Alternative sein. Stromale Knochenmarkzellen, die Osteoblasten differenzieren können, und endotheliale Vorläuferzellen, die die Vaskularisierung der Defektzone unterstützen, zeigten sich effektiv in tierexperimentellen Studien; jedoch müssen diese Zellen vor Verwendung über einen längeren Zeitraum in Kultur expandiert werden. Dies kann jedoch zu einer Akkumulation genetischer Schäden und möglicherweise zu einer Entartung der transplantierten Zellen führen. Bone marrow mononuclear cells (BMC) stellen eine interessante Alternative dar, sie können innerhalb weniger Stunden isoliert und dem Patienten zurückgegeben werden. Ziel dieser Arbeit war daher, die Adhäsion und funktionelle Aspekte von BMC auf drei verschiedenen Knochenersatzmaterialien zu analysieren.
Im ersten Versuchsteil wurde untersucht, ob es möglich ist, BMC auf einem β-Tricalciumphosphat (β-TCP)-Scaffold auszusäen, und ob eine Beschichtung des Scaffolds eine positive Auswirkung auf die BMC-Adhäsion und Aktivität hat. Hierbei wurde eine Beschichtung mit humanem Plasma (FFP) und Fibronektin gegen eine Kontrolle verglichen. Es konnte gezeigt werden, dass BMC auf unbeschichtetem β-TCP adhärieren und dass eine Vorbeschichtung des Scaffolds mit Fibronektin oder mit FFP zu keiner weiteren Verbesserung der initialen Adhäsion führt. FACS-Analysen zeigten, dass der Prozentsatz der auf dem Material adhärierenden Fraktionen regenerativer Zellen dem Prozentsatz der in der Kontrolle enthaltenen regenerativen Zellen entspricht. Überdies konnte eine endotheliale Differenzierung der ausgesäten BMC beobachtet werden. Die Anzahl adhärierender BMC war zum ersten Messpunkt an Tag zwei unabhängig von der Vorbeschichtung am höchsten. Interessanterweise war die Zahl der adhärierenden BMC auf unbeschichtetem Material signifikant gegenüber den beschichteten Materialien erhöht.
Basierend auf der Beobachtung, dass eine Vorbeschichtung der Trägersubstanz nicht zu einer Verbesserung der BMC-Adhäsion auf dem Gerüststoff führt, wurden im zweiten Versuchsteil unbeschichtete Gerüststoffe miteinander verglichen. Für diese Arbeit wurden drei aus verschiedenen Klassen der Knochenersatzmaterialien stammende Scaffolds gewählt. ChronOs® als Vertreter der β-TCPs, Cerabone®, eine verarbeitete bovine Knochenmatrix, und Demineralized Bone Matrix (DBM), ein sterilisiertes humanes Knochentransplantat. Die Untersuchungen ergaben signifikante Unterschiede in der Aussaateffizienz der Zellen auf den Materialien und der Zellaktivität im Verlauf über 21 Tage. DBM zeigte hier im Materialvergleich die besten Ergebnisse. In unserem Versuch zeigte sich die Menge der absorbierten Flüssigkeit im Verhältnis zur Materialmenge bei DBM signifikant erhöht gegenüber den beiden anderen Materialien. Zudem konnte mittels HE- und Kern-Färbung (DAPI) der Nachweis erbracht werden, dass sich Zellen tief im Inneren des Materials anlagern. MTT-Tests zeigten an Tag 14 eine signifikant erhöhte metabolische Aktivität auf DBM gegenüber Cerabone® und an Tag 21 gegenüber beiden Vergleichsmatrices. Wir konnten auf allen Materialien an Tag 2 eine signifikant erhöhte VEGF-Produktion feststellen. Mittels Real-Time-PCR ließ sich eine VEGF-Genexpression in BMC auf allen Materialien bis Tag 14 und auf DBM über die kompletten 21 Tage nachweisen. Die Genexpression von vWF konnte ebenfalls auf allen Materialien über den gesamten Zeitraum nachgewiesen werden.
Zusammengefasst konnte durch diese Studie belegt werden, dass die initiale Adhärenz von BMC auf unbeschichtete Knochenersatzmaterialien generell hoch ist, aber signifikante materialspezifische Unterschiede in der Aussaateffizienz und nachfolgend der metabolischen Aktivität und der VEGFSynthese der BMC existieren. Humanes Knochenersatzmaterial zeigte sich in unserer Studie als überlegen. Daher sollte die Art des Knochenersatzmaterials für den künftigen klinischen Einsatz von BMC Berücksichtigung finden.
Purpose: Every physician must be able to sufficiently master medical emergencies, especially in medical areas where emergencies occur frequently such as in the emergency room or emergency surgery. This contrasts with the observation that medical students and young residents often feel insufficiently prepared to handle medical emergencies. It is therefore necessary to train them in the treatment of emergency patients. The aim of this study is to analyze the influence of the assignment of manikin versus simulated patients during a training for undergraduate medical students on learning outcomes and the perceived realism.
Methods: The study had a prospective cross-over design and took place in a 3-day emergency medicine training for undergraduate medical students. Students completed three teaching units (‘chest pain’, ‘impaired consciousness’, ‘dyspnea’), either with manikin or simulated patient. Using a questionnaire after each unit, overall impression, didactics, content, the quality of practical exercises, and the learning success were evaluated. The gained competences were measured in a 6-station objective structured clinical examination (OSCE) at the end of training.
Results: 126 students participated. Students rated simulated patients as significantly more realistic than manikins regarding the possibility to carry out examination techniques and taking medical history. 54.92% of the students would prefer to train with simulated patients in the future. Regarding the gained competences for ‘chest pain’ and ‘impaired consciousness’, students who trained with a manikin scored less in the OSCE station than the simulated patients-group.
Conclusion: Simulated patients are rated more realistic than manikins and seem to be superior to manikins regarding gained competence.
Hintergrund: Aufgrund des Nachwuchsmangels muss die Chirurgie vermehrt für die Weiterbildung zum Chirurgen begeistern. Studierende bemängeln, dass ihr Unterricht nachrangig zur Patientenversorgung und durch die Faktoren Zeit und ärztliches Personal limitiert ist. Obwohl es viele Arbeiten mit Fokus auf die Studierenden gibt, fehlen Arbeiten mit dem Fokus auf die Sicht der Lehrenden. Ziel der Arbeit: Die Lehre im Fach Chirurgie im Stationsalltag und Ursachen von Problemen hierbei sollen aus Sicht der Lehrenden analysiert werden. Material und Methoden: Im Rahmen der prospektiven Studie wurde ein Leitfaden für semistrukturierte Interviews mit ausformulierten, offenen Fragen erstellt, die mit weiteren Spezifizierungsfragen versehen wurden. Alle Interviews wurden anhand des Leitfadens geführt und aufgezeichnet. Die Anzahl der Interviews ergab sich aus dem Prinzip der inhaltlichen Sättigung. Ergebnisse: Alle der 22 befragten Ärzte messen der Lehre im klinischen Alltag einen hohen Stellenwert bei. Dennoch beschreiben sie, dass die Lernziele im klinischen Alltag nicht immer erreicht werden. Als Hauptgrund hierfür wird die mangelnde Zeit genannt. Mit zunehmender klinischer Erfahrung kommen jedoch weitere Faktoren hinzu: Ober- und Chefärzte beklagen die zu geringen Vorkenntnisse und die zu geringe Motivation einiger Studierender. Die meisten Befragten beschreiben, keine Anerkennung für ihre Lehre zu erhalten. Insgesamt wird die studentische Lehre als zusätzliche Belastung wahrgenommen, die aber alle Befragten für lohnenswert halten. Diskussion: Neben Personalmangel ist die fehlende Anerkennung das wichtigste Hemmnis für eine effektive Lehre. Es ist daher wichtig, die Wertigkeit der Lehre durch die Belohnung guter Lehrleistungen und Schaffung einer dahingehenden Transparenz zu erhöhen.
Purpose: Every physician must be able to sufficiently master medical emergencies, especially in medical areas where emergencies occur frequently such as in the emergency room or emergency surgery. This contrasts with the observation that medical students and young residents often feel insufficiently prepared to handle medical emergencies. It is therefore necessary to train them in the treatment of emergency patients. The aim of this study is to analyze the influence of the assignment of manikin versus simulated patients during a training for undergraduate medical students on learning outcomes and the perceived realism.
Methods: The study had a prospective cross-over design and took place in a 3-day emergency medicine training for undergraduate medical students. Students completed three teaching units (‘chest pain’, ‘impaired consciousness’, ‘dyspnea’), either with manikin or simulated patient. Using a questionnaire after each unit, overall impression, didactics, content, the quality of practical exercises, and the learning success were evaluated. The gained competences were measured in a 6-station objective structured clinical examination (OSCE) at the end of training.
Results: 126 students participated. Students rated simulated patients as significantly more realistic than manikins regarding the possibility to carry out examination techniques and taking medical history. 54.92% of the students would prefer to train with simulated patients in the future. Regarding the gained competences for ‘chest pain’ and ‘impaired consciousness’, students who trained with a manikin scored less in the OSCE station than the simulated patients-group.
Conclusion: Simulated patients are rated more realistic than manikins and seem to be superior to manikins regarding gained competence.
Background: Surgical complications are associated with a significant burden to patients and hospitals and are increasingly discussed in recent literature. This cohort study reviewed surgery-related complications in a Level I trauma center. The effect of a complication avoidance care bundle on the rate of surgical complications was analyzed. Methods: All complications (surgical and nonsurgical) that occur in our trauma department are prospectively captured using a standardized documentation form and are discussed and analyzed in a weekly trauma Morbidity and Mortality (M&M) conference. Surgical complication rates are calculated using the annual surgical procedure numbers. Based on discussions in the M&M conference, a complication avoidance care bundle consisting of five measures was established: (1) Improving team situational awareness; (2) reducing operating room traffic by staff members and limiting door-opening events; (3) preoperative screening for infectious foci; (4) adapted preoperative antibiotic prophylaxis in anatomic regions with a high risk of infectious complications; and (5) use of iodine-impregnated adhesive drape. Results: The number of surgical procedures steadily increased over the study years, from 3587 in 2015 to 3962 in 2019 (an increase of 10.5%). Within this 5-year study period, the overall rate of surgical complications was 0.8%. Surgical site infections were the most frequently found complications (n = 40, 24.8% of all surgical complications), followed by screw malposition (n = 20, 12.4%), postoperative dislocations of arthroplasties (n = 18, 11.2%), and suboptimal fracture reduction (n = 18, 11.2%). Following implementation of the complication avoidance care bundle, the overall rate of surgical complications significantly decreased, from 1.14% in the year 2016 to 0.56% in the study year 2019, which represents a reduction of 51% within a 3-year time period. Conclusions: A multimodal strategy targeted at reducing the surgical complication rate can be successfully established based on a transparent discussion of adverse surgical outcomes. The combination of the different preventive measures was associated with reducing the overall complication rate by half within a 3-year time period.
The rapid detection of pathogens in infected wounds can significantly improve the clinical outcome. Wound exudate, which can be collected in a non-invasive way, offers an attractive sample material for the detection of pathogens at the point-of-care (POC). Here, we report the development of a nucleic acid lateral flow immunoassay for direct detection of isothermally amplified DNA combined with fast sample preparation. The streamlined protocol was evaluated using human wound exudate spiked with the opportunistic pathogen Pseudomonas aeruginosa that cause severe health issues upon wound colonization. A detection limit of 2.1 × 105 CFU per mL of wound fluid was achieved, and no cross-reaction with other pathogens was observed. Furthermore, we integrated an internal amplification control that excludes false negative results and, in combination with the flow control, ensures the validity of the test result. The paper-based approach with only three simple hands-on steps has a turn-around time of less than 30 min and covers the complete analytical process chain from sample to answer. This newly developed workflow for wound fluid diagnostics has tremendous potential for reliable pathogen POC testing and subsequent target-oriented therapy.
Falls from a height are a common cause of polytrauma care in Level I Trauma Centers worldwide. The expected injury consequences depend on the height of the fall and the associated acceleration, as well as the condition of the ground. In addition, we further hypothesize a correlation between the cause of the fall, the age of the patient, and the patient’s outcome. A total of 178 trauma patients without age restriction who were treated in our hospital after a fall >3 m within a 5-year period were retrospectively analyzed. The primary objective was a clinically and radiologically quantifiable increase in the severity of injuries after falls from different relevant heights (>3 m, >6 m, and >9 m). The cause of the fall, either accidental or suicidal; age and duration of intensive care unit stay, including duration of ventilation; and total hospital stay were analyzed. Additionally, the frequency of urgent operations, such as, external fixation of fractures or hemi-craniectomies, laboratory parameters; and clinical outcomes were also among the secondary objectives. Sustaining a thoracic trauma or pelvis fractures increases significantly with height, and vital parameters are significantly compromised. We also found significant differences in urgent pre- and in-hospital emergency interventions, as well as organ complications and outcome parameters depending on the fall’s height.