Biomechanischer Vergleich verschiedener Verfahren zur arthroskopischen suprapectoralen Tenodese der langen Bizepssehne

Fragestellung Biomechanischer Vergleich drei verschiedener Fixationstechniken für die proximale Bizepstenodese. Methodik Achtzehn humane Schulterpräparate wurden für die Tests verwendet. Eine Tenodese der proximalen Bizepssehne wurde mit einem doppelt armierten Schraubanker (5,5-mm Corkscrew, Arthrex), einem knotenfreien Schraubanker (5,5-mm SwiveLock, Arthrex) oder einem gegabelten knotenfreien Schraubanker (8-mm SwiveLock, Arthrex) durchgeführt. Die Rekonstruktionen wurden mittels Materialprüfmaschine zyklisch für je 50 Zyklen von 10-60 und 10-100 N belastet. Die zyklische Dislokation wurde mit Hilfe eines Videoextensometers bestimmt. Im Anschluss wurde die maximale Versagenslast und der Versagensmodus der rekonstruierten Sehnen ermittelt. Ergebnisse Bei 60 N zeigte sich eine Elongation unter zyklischer Belastung von durchschnittlich 3,3 ± 1,1 mm für den armierten Schraubanker, 5,4 ± 1,4 mm für den knotenfreien 5,5-mm Schraubanker und 2,9 ± 1,6 mm für den knotenfreien gegabelten 8-mm Schraubanker. Unter 100 N zyklischer Belastung wurden 5,1 ± 2,2 mm für den armierten Schraubanker, 8,7 ± 2,5 mm für den knotenfreien 5,5-mm Schraubanker und 4,8 ± 3,3 mm für den knotenfreien 8-mm Schraubanker gemessen. Der armierte Schraubanker (p = 0,020) und der knotenfreie 8-mm Schraubanker (p = 0,023) zeigten eine signifikant geringere Dislokation unter zyklischer Belastung im Vergleich zum knotenfreien 5,5-mm Schraubanker bei 60 N. Bezüglich der maximalen Versagenslast wurden 109 ± 27 N für den armierten Schraubanker gemessen, 125 ± 25 N wurden für den knotenfreien 5,5-mm- Schraubanker ermittelt. Der knotenfreie 8-mm Schraubanker zeigte eine durchschnittliche Versagenslast von 175 ± 42 N. Der knotenfreie 8-mm Schraubanker zeigte hier eine signifikant höhere maximale Versagenslast im Vergleich zum knotenfreien 5,5-mm Schraubanker (p = 0,044) und dem armierten Schraubanker (p = 0,009). Keine signifikanten Unterschiede wurden zwischen dem armierten Schraubanker und dem knotenlosen 5,5-mm Schraubanker gefunden. Schlussfolgerung Der neue knotenfreie gegabelte 8-mm Schraubanker führt zu einer signifikant höheren Konstruktstabilität im Vergleich zum knotenfreien 5,5-mm Schraubanker und dem doppelt armierten Schraubanker. Jedoch scheint eine restriktive postoperative Rehabilitation unabhängig vom eingesetzten Konstrukt von Bedeutung zu sein, um ein frühes Versagen der Rekonstruktion zu vermeiden.Purpose Biomechanical comparison of three different fixation techniques for a proximal biceps tenodesis. Methods Eighteen human cadaver specimens were used for the testing. A tenodesis of the proximal biceps tendon was performed using a double-loaded suture anchor (5.5-mm Corkscrew, Arthrex), a knotless anchor (5.5-mm SwiveLock, Arthrex) or a forked knotless anchor (8-mm SwiveLock, Arthrex). Reconstructions were cyclically loaded for 50 cycles from 10-60 to 10-100 N. Cyclic displacement and ultimate failure loads were determined, and mode of failure was evaluated. Results Cyclic displacement at 60 N revealed a mean of 3.3 ± 1.1 mm for the Corkscrew, 5.4 ± 1.4 mm for the 5.5-mm SwiveLock and 2.9 ± 1.6 mm for the 8-mm forked SwiveLock. At 100 N, 5.1 ± 2.2 mm were seen for the Corkscrew anchor, 8.7 ± 2.5 mm for the 5.5-mm SwiveLock and 4.8 ± 3.3 mm for the 8-mm forked SwiveLock anchor. Significant lower cyclic displacement was seen for the Corkscrew anchor (p = 0.020) as well as the 8-mm SwiveLock anchor (p = 0.023) compared to the 5.5-mm Swive- Lock anchor at 60 N. An ultimate load to failure of 109 ± 27 N was found for the Corkscrew anchor, 125 ± 25N were measured for the 5.5-mm SwiveLock anchor, and 175 ± 42 N were found for the 8-mm forked SwiveLock anchor. Significant differences were seen between the 8-mm SwiveLock compared to the 5.5-mm SwiveLock (p = 0.044) as well as the Corkscrew anchor (p = 0.009). No significant differences were seen between the Corkscrew and the 5.5-mm SwiveLock anchor. Conclusions The new 8-mm forked SwiveLock anchor significantly enhances construct stability compared to a 5.5-mm double-loaded Corkscrew anchor as well as the 5.5-mm SwiveLock suture anchor. However, a restrictive postoperative rehabilitation seems to be important in all tested reconstructions in order to avoid early failure of the construct

Laser induzierte Geweberemodellierung des Trommelfells

Erkrankungen des Mittelohres, wie rezidivierende Mittelohrentzündungen, führen im klinischen Alltag häufig zu einer Schwächung der Trommelfellspannung, gefolgt von Schallleitungsschwerhörigkeit und möglicher Bildung eines Adhäsivprozesses. Die Therapie der Wahl ist aktuell ein operativer Eingriff (Tympanoplastik) zur Stabilisierung des geschwächten Trommelfells, der mit einem großen operativen Aufwand und hohen Krankenhauskosten einhergeht. Mit dem Hintergrund eine alternative Therapie zu ent-wickeln, war das Ziel der hier vorgestellten Studie die experimentelle Durchführung einer nicht-invasiven Stabilisierung des Trommelfells mittels Laserbestrahlung im Tier-modell. Hierbei sollte die Auswirkung verschiedener Laserparameter auf die Gewe-beremodellierung des Trommelfells am Beispiel eines Mausmodells erfolgen. Dazu wur-den an CD1 Mäusen (n = 79) das Trommelfell beider Ohren exponiert und auf einen Teil des Trommelfells (posteriorer oberer Quadrant) das Pigment Fuchsin aufgetragen, um eine gezielte lokal begrenzte Wirkung der Bestrahlung zu gewährleisten. Beim linken Ohr wurde jeweils ein ca. 500 m großer Bereich des pigmentierten Trommelfells für 30 s mit 532 nm Laserpulsen von 10 mW (5 J), 25 mW (12,5 J) oder 50 mW (25 J) bei 2 kHz Pulsfrequenz bestrahlt, wobei das unbestrahlte Gegenohr hierbei als Kontrolle dien-te. Auditorische Hirnstammpotentiale wurden zu drei unterschiedlichen Zeitpunkten abgeleitet um die Auswirkungen der Bestrahlung auf das Hörvermögen der Tiere zu überprüfen. Die Felsenbeine wurden daraufhin explantiert um strukturelle Veränderun-gen des Trommelfells in histologischen Untersuchungen zu evaluieren. Eine Zunahme der Dicke des Trommelfells konnte bereits ab der zweiten Woche nach der Laserbe-handlung demonstriert und eine Erhöhung der Polarisation des Trommelfells ab Woche vier festgestellt werden. Direkt nach der Bestrahlung kam es zu keiner Verschlechterung der Hörschwellen. In dieser präklinischen Studie konnte gezeigt werden, dass eine ge-zielte Kollagenremodellierung und –neubildung durch Laserbestrahlung in einem vorde-finierten Bereich des Trommelfells induziert werden konnte. Es ist die erste Studie ihrer Art, welche sich mit der histologischen Analyse des Trommelfells nach Laserbestrahlung beschäftigt. Die Ergebnisse bieten das Potential als Grundlage für zukünftige Studien zur Wiederherstellung der Trommelfellspannung als Alternative zur etablierten, invasiv operativen Therapie der Trommelfellstabilisierung.Middle ear diseases, such as recurrent otitis media, often lead to a weakening of the tympanic membrane tension, followed by conductive hearing loss and the possible for-mation of an adhesive process. The therapy of choice is currently a surgical procedure (tympanoplasty) to stabilize the weakened eardrum, which is associated with a high lev-el of surgical effort and high hospital costs. With the background of developing an al-ternative therapy, the aim of the study presented here was the experimental implementa-tion of a non-invasive stabilization of the eardrum using laser radiation in an animal model. The effect of various laser parameters on tissue remodeling of the eardrum should be evaluated on the example of a mouse model. For this purpose, the eardrum of both ears was exposed on test CD1 mice (n = 79) and the pigment fuchsin was applied to part of the eardrum (posterior upper quadrant) in order to ensure a targeted, locally limited effect of the radiation. In the left ear, an area of approximately 500 µm of the the pigmented eardrum was irradiated for 30 s with 532 nm laser pulses of 10 mW (5 kJ), 25 mW (12.5 kJ) or 50 mW (25 kJ) 2 kHz pulse frequency, the unirradiated counter ear serving as a control. Auditory brainstem potentials were derived at three different times to evaluate the effects of radiation on the hearing of the animals. The petrous bones were then explanted to evaluate structural changes to the eardrum in histological examinations. An increase in the thickness of the tympanic membrane was demonstrated as early as the second week after the laser treatment and an increase in the polarization of the eardrum was observed from week four. The hearing thresholds did not increase immediately after the radiation. In this preclinical study, it could be shown that targeted collagen remodeling and regeneration by laser radiation could be induced in a prede-fined area of the tympanic membrane, which indicates regeneration of the eardrum. It is the first study of its kind to deal with the histological analysis of the eardrum after laser treatment. The results offer the potential to serve as a basis for future studies to restore the tympanic membrane as an alternative to the established, invasive operative therapy of tympanic membrane stabilization.European Research Council under the European Union’s Seventh Framework Program (FP/2007-2013)/ERC Gran

Parallelizable Microfluidic Platform to Model and Assess In Vitro Cellular Barriers: Technology and Application to Study the Interaction of 3D Tumor Spheroids with Cellular Barriers

Endothelial and epithelial cellular barriers play a vital role in the selective transport of solutes and other molecules. The properties and function of these barriers are often affected in case of inflammation and disease. Modelling cellular barriers in vitro can greatly facilitate studies of inflammation, disease mechanisms and progression, and in addition, can be exploited for drug screening and discovery. Here, we report on a parallelizable microfluidic platform in a multiwell plate format with ten independent cell culture chambers to support the modelling of cellular barriers co-cultured with 3D tumor spheroids. The microfluidic platform was fabricated by microinjection molding. Electrodes integrated into the chip in combination with a FT-impedance measurement system enabled transepithelial/transendothelial electrical resistance (TEER) measurements to rapidly assess real-time barrier tightness. The fluidic layout supports the tubeless and parallelized operation of up to ten distinct cultures under continuous unidirectional flow/perfusion. The capabilities of the system were demonstrated with a co-culture of 3D tumor spheroids and cellular barriers showing the growth and interaction of HT29 spheroids with a cellular barrier of MDCK cells

Man against Machine: Diagnostic performance of a deep learning convolutional neural network for dermoscopic melanoma recognition in comparison to 58 dermatologists

Background: Deep learning convolutional neural networks (CNN) May facilitate melanoma detection, but data comparing a CNN\u2019s diagnostic performance to larger groups of dermatologists are lacking. Methods: Google\u2019s Inception v4 CNN architecture was trained and validated using dermoscopic images and corresponding diagnoses. In a comparative cross-sectional reader study a 100-image test-set was used (level-I: dermoscopy only; level-II: dermoscopy plus clinical information and images). Main outcome measures were sensitivity, specificity and area under the curve (AUC) of receiver operating characteristics (ROC) for diagnostic classification (dichotomous) of lesions by the CNN versus an international group of 58 dermatologists during level-I or -II of the reader study. Secondary end points included the dermatologists\u2019 diagnostic performance in their management decisions and differences in the diagnostic performance of dermatologists during level-I and -II of the reader study. Additionally, the CNN\u2019s performance was compared with the top-five algorithms of the 2016 International Symposium on Biomedical Imaging (ISBI) challenge. Results: In level-I dermatologists achieved a mean (6standard deviation) sensitivity and specificity for lesion classification of 86.6% (69.3%) and 71.3% (611.2%), respectively. More clinical information (level-II) improved the sensitivity to 88.9% (69.6%, P \ubc 0.19) and specificity to 75.7% (611.7%, P < 0.05). The CNN ROC curve revealed a higher specificity of 82.5% when compared with dermatologists in level-I (71.3%, P < 0.01) and level-II (75.7%, P < 0.01) at their sensitivities of 86.6% and 88.9%, respectively. The CNN ROC AUC was greater than the mean ROC area of dermatologists (0.86 versus 0.79, P < 0.01). The CNN scored results close to the top three algorithms of the ISBI 2016 challenge. Conclusions: For the first time we compared a CNN\u2019s diagnostic performance with a large international group of 58 dermatologists, including 30 experts. Most dermatologists were outperformed by the CNN. Irrespective of any physicians\u2019 experience, they May benefit from assistance by a CNN\u2019s image classification

Metal ion levels in large-diameter total hip and resurfacing hip arthroplasty-Preliminary results of a prospective five year study after two years of follow-up

<p>Abstract</p> <p>Background</p> <p>Metal-on-metal hip resurfacing is an alternative to metal-on-metal total hip arthroplasty, especially for young and physically active patients. However, wear which might be detected by increased serum ion levels is a matter of concern.</p> <p>Methods</p> <p>The aims of this preliminary study were to determine the raise of metal ion levels at 2-years follow-up in a prospective setting and to evaluate differences between patients with either resurfacing or total hip arthroplasty. Furthermore we investigated if the inclination of the acetabular component and the arc of cover would influence these findings. Therefore, 36 patients were followed prospectively.</p> <p>Results</p> <p>The results showed increments for Co and Cr in both implant groups. Patients treated with large-diameter total hip arthroplasty showed fourfold and threefold, respectively, higher levels for Co and Cr compared to the resurfacing group (Co: p < 0,001 and Cr: p = 0,005). Nevertheless, we observed no significant correlation between serum ion levels, inclination and arc of cover.</p> <p>Discussion</p> <p>In order to clarify the biologic effects of ion dissemination and to identify risks concerning long-term toxicity of metals, the exposure should be monitored carefully. Therefore, long-term studies have to be done to determine adverse effects of Co and Cr following metal-on-metal hip replacement.</p