Biomechanische Analyse eines bionischen Plattendesigns zur Versorgung von Kalkaneusfrakturen

In der vorliegenden Arbeit wurde ein neuartiger Versuchsaufbau zur biomechanischen Testung eines bionischen und eines konventionellen Plattendesigns zur Versorgung von Kalkaneusfrakturen, insbesondere auf Stabilität und Materialermüdung, entwickelt. Die Versuche wurden an zwölf Platten, jeweils sechs der bionischen und sechs der konventionellen winkelstabilen Osteosynthesen, durchgeführt. Das bionische Plattendesign tolerierte eine signifikant längere Belastungszeit, eine signifikant höhere axiale Kraft und zeigte eine signifikant geringere Auslenkung unter zyklischer Belastung. Die neuartige Plattenarchitektur bietet eine höhere Stabilität und Belastbarkeit bei geringerer Materialermüdung verglichen mit dem konventionellen Plattendesign

Optimized design and techno-economic analysis of novel DME production processes

The shift from gas to liquid phase DME synthesis enables an intensified process concept towards efficient large scale DME production. In this work, four process concepts based on liquid phase DME synthesis were proposed and optimized. A comprehensive economic model was applied with the objective of minimizing the total production cost. All concepts were evaluated applying our previously validated reaction kinetics for commercial ion exchange resin selected catalysts. Furthermore, every process concept was studied with a pure MeOH feed and water-rich (crude) MeOH feedstock. The conventional gas-phase DME production process was simulated and evaluated using the same technical and economic parameters to serve as a benchmark. Using a chlorinated high temperature stable IER catalyst led to significant cost reduction in all the considered concepts. This was due to the higher reaction rate enabled by the higher operating temperature of this catalyst. In the integrated process concept with H2 and CO2 as sustainable feedstocks, it was shown that the reactive distillation process shows a 27% lower production cost, when the crude methanol is directly fed to the DME process instead of being purified in a dedicated crude methanol distillation column. A further techno-economic optimization can be achieved when complementing the reactive distillation column with an additional reactor. Overall, the process concept of a reactive distillation column with a side reactor presents the most promising process concept, enabling a 39% lower production cost than the conventional gas-phase process. By heat integration with a CO2-based MeOH plant, a DME production technology with no external heat demand and a net conversion cost of 54.4 € per tDME is possible

Ellenbogengelenkluxation : Häufige Begleitverletzungen und aktuelle Therapiekonzepte

Zusammenfassung Luxationen des Ellenbogengelenks sind nach Schultergelenkluxationen eine der häufigsten Luxationsverletzungen am menschlichen Körper und stellen wegen ihrer Begleitverletzungen und Komplikationen weiterhin eine Herausforderung im klinischen Alltag dar. Betroffen sind v. a. junge Erwachsene, die sich während ihrer sportlichen oder alltäglichen Tätigkeiten verletzen. Unterschieden wird i. Allg. zwischen einer einfachen Ellenbogenluxation und einer Ellenbogenluxationsfraktur. Eine einheitliche Klassifikation oder ein Therapiealgorithmus hat sich jedoch insbesondere für die einfache Ellenbogenluxation mit den damit verbundenen ligamentären, muskulären und kapsulären Begleitverletzungen noch nicht durchgesetzt. Aufgrund dessen und wegen der Komplexität dieser Verletzung bedarf es eines standardisierten Vorgehens, um frühzeitig die optimale Therapie zu initiieren und den schmalen Behandlungspfad zwischen drohender chronischer Instabilität und Ellenbogensteife richtig auszuwählen. --------------------------------------------------- Dislocations of the elbow joint are among the most prevalent dislocation injuries in the human body after shoulder joint dislocations and represent a challenge in the clinical routine because of the concomitant injuries and complications. They predominantly affect young adults who become injured during athletic or daily activities. A distinction is generally made between a simple elbow dislocation and a dislocation fracture of the elbow; however, a uniform classification or treatment algorithm has not yet been established, especially for simple elbow dislocations with associated ligamentous, muscular and capsular concomitant injuries. Due to this and the complexity of this injury, a standardized approach is needed to initiate the optimal treatment at an early stage and to correctly select the narrow treatment pathway between impending chronic instability and elbow stiffness

Die implantatlose Loop-Tenodese der langen Bizepssehne: Technik und funktionelle Ergebnisse

Ausgehend von der Idee der Autotenodese nach Tenotomie der langen Bizepssehne (LBS) wurde die neue implantatlose Loop-Tenodesetechnik eingeführt, welche durch Vergrößerung des Durchmessers der Bizepssehnenstumpfes die Autotenodese im Sulcus bicipitalis verbessert und somit eine stabile Verankerung der LBS im Sulcus ohne die Notwendigkeit eines Implantats erreichen soll. Die Vergrößerung des Bizepssehnenstumpfes wird bei der Technik durch die Anlage einer Sehnenschlaufe am Sehnenstumpf nach der Tenotomie erzielt. Hierdurch verblockt sich die proximale Sehne im Sulcus und ein Gleiten der Sehne durch den Sulcus mit Distalisation des Muskelbauchs und konsekutiver kosmetischer Deformität und Kraftminderung wird verhindert. Nach der Veröffentlichung der Operationstechnik im Jahr 2019 wurde das Verfahren zunächst in einer biomechanischen Untersuchung getestet, bei der die Loop-Tenodese mit der Tenotomie an menschlichen Präparaten verglichen wurde. Die maximale Belastbarkeit war bei der Loop-Tenodese signifikant höher als in der Tenotomiegruppe. Ein Versagen der Loop-Tenodese konnte nur im Falle einer vollständigen Sehnenruptur distal des Loops beobachtet werden. Aufgrund der vielversprechenden Ergebnisse wurde die Loop-Tenodese in einer prospektiven klinischen Studie erprobt. Die Studienpatienten berichteten 6 Monate nach der chirurgischen Behandlung über eine signifikante Verbesserung des Constant Scores, des LHB-Score („long head of biceps“), der Schmerzen und des Bewegungsumfangs. Die Ergebnisse der Loop-Tenodese waren in den bisherigen Analysen vergleichbar mit dem Ergebnis nach suprapektoralen Ankertenodese in früheren Studien

Two-Dimensional Visualization of the Three-Dimensional Planned Sacroiliac Screw Corridor with the Slice Fusion Method

Insertion of sacro-iliac (SI) screws for stabilization of the posterior pelvic ring without intraoperative navigation or three-dimensional imaging can be challenging. The aim of this study was to develop a simple method to visualize the ideal SI screw corridor, on lateral two-dimensional images, corresponding to the lateral fluoroscopic view, used intraoperatively while screw insertion, to prevent neurovascular injury. We used multiplanar reconstructions of pre- and postoperative computed tomography scans (CT) to determine the position of the SI corridor. Then, we processed the dataset into a lateral two-dimensional slice fusion image (SFI) matching head and tip of the screw. Comparison of the preoperative SFI planning and the screw position in the postoperative SFI showed reproducible results. In conclusion, the slice fusion method is a simple technique for translation of three-dimensional planned SI screw positioning into a two-dimensional strict lateral fluoroscopic-like view

Präklinische Polytraumaversorgung

Tscherne was the first to define the term polytrauma in 1966 as “multiple injuries to different regions of the body sustained simultaneously, with at least one injury or the combination of these injuries being life-threatening”. This definition highlights the essential pathophysiological paradigm of polytrauma, with the life-threating characteristics resulting from injuries to multiple organ systems. The treatment of polytrauma patients begins at the scene of the accident. Important life-saving initial interventions can already be carried out on site through targeted measures and expertise of the emergency medical service team, thus improving patient survival. The advanced trauma life support/prehospital trauma life support (ATLS/PHTLS) concept is the worldwide gold standard. As prehospital treatment of severely injured patients is not routine for most emergency teams, concepts and emergency interventions must be regularly trained. This is the prerequisite for safe and effective emergency treatment in this time-critical situation

Patient-related outcome of unstable pelvic ring fractures stabilized with a minimal invasive screw-rod system

Background: Clinical and radiological outcomes of operatively treated unstable pelvic ring fractures are well documented, whereas little is known about the patient's related outcome. The purpose of this study is to evaluate the patient-reported outcome after minimal invasive treatment of pelvic ring fractures using the SF-36 and EQ-5D medical outcome scores. Methods: Patients with unstable pelvic ring fractures treated in our trauma department with a minimal invasive screw-rod system between 01/2004 and 12/2014 were included. Next to patient data (sex, age), injury related details (fracture type, additional injuries, Injury Severity Score (ISS)) as well as operation details (method, time to operation, general complications, adverse events associated with the surgical procedure, revision surgery, fracture reduction) were assessed. The patient related outcome was evaluated using the SF-36 and the EQ-5D score. Results: A total of 105 patients (57 men; 48 women; mean age 56 +/- 21 years) were identified as candidates for the study. 60 patients completed the SF-36 and EQ-5D score after a mean follow-up of five years (60.5 months (14-142 months)). Of these patients 77% were multiply injured with a mean ISS of 26 +/- 19. Within the respondent group 22% showed type B and 78% type C pelvic ring fractures. In 82% the dorsal pelvic ring fracture was stabilized using a minimally invasive transiliac internal fixator, in 18% an iliolumbar fixation was performed respectively. The mean physical component score of the SF-36 was 37.9 +/- 12.0, the mean mental component score was 49.8 +/- 12.5. The mean EQ-5D VAS reached 70.5 +/- 24.4. Conclusion: Patients being multiply injured and treated with minimal invasive treated dorsal pelvic ring fractures were suffering more especially concerning physical domains compared to the healthy reference population. Nevertheless, the overall patient-related outcome is comparable to pelvic ring fractures in general

Does Dynamic Anterior Plate Fixation Provide Adequate Stability for Traumatic Subaxial Cervical Spine Fractures at Mid-Term Follow-Up?

Background: It remains questionable if the treatment of cervical fractures with dynamic plates in trauma surgery provides adequate stability for unstable fractures with disco-ligamentous injuries. The primary goal of this study was to assess the radiological and mid-term patient-reported outcome of traumatic subaxial cervical fractures treated with different plate systems. Patients and Methods: Patients, treated with anterior cervical discectomy and fusion (ACDF) between 2001 and 2015, using either a dynamic plate (DP: Mambo™, Ulrich, Germany) or a rigid locking plate (RP: CSLP™, Depuy Synthes, USA), were identified. For radiological evaluation, the sagittal alignment, the sagittal anterior translation and the bony consolidation were evaluated. After at least two years, the patient-reported outcome measures (PROM) were evaluated using the German Short-Form 36 (SF-36), Neck Disability Index (NDI) and the EuroQol in 5 Dimensions (EQ-5D) scores. Results: 33 patients met the inclusion criteria (DP: 13; RP:20). Twenty-six patients suffered from AO Type B or C fractures. Both the sagittal alignment and the sagittal translation could be sufficiently improved in both groups (p ≥ 0.05). No significant loss of reduction could be observed at the follow-up in both groups (p ≥ 0.05). Bony consolidation could be observed in 30 patients (DP: 12/13 (92%); RP: 18/20 (90%); (p ≥ 0.05)). In 20 patients, PROMs could be evaluated (follow-up: 71.2 ± 25.5 months). The whole cohort showed satisfactory PROM results (EQ-5D: 72.0 ± 4.9; SF-36 PCS: 41.9 ± 16.2, MCS: 45.4 ± 14.9; NDI: 11.0 ± 9.1). without significant differences between the DP and RP group (p ≥ 0.05) Conclusion: The dynamic plate concept provides enough stability without a difference in fusion rates in comparison to rigid locking plates in a population that mostly suffered fragile fractures

Severe thoracic trauma – still an independent predictor for death in multiple injured patients?

Background: Over the past, the severe thoracic trauma has had decisive influence on the outcome of multiple injured patients. Today, new therapies (e.g. extracorporeal membrane oxygenation (ECMO), protective ventilation methods and new forms of patient positioning) are available and applied regularly. What impact on the patient's outcome does the thoracic trauma have today? Methods: Prospective data collection of multiple injured patients in a level-I trauma center was performed between 2008 and 2014. Patients with an ISS >= 16 were included and divided into 2 groups: Severe thoracic trauma (STT: AIS(Thorax) >= 3) and mild thoracic trauma (MTT: AIS(Thorax) < 3). In addition to preclinical and trauma room care, detailed information about clinical course and outcome were assessed. Results: In total, 529 patients (STT: n = 317; MTT: n = 212) met the in-and exclusion criteria. The mean Injury Severity Score (ISS) was significantly higher in patients of the STT group (STT: 33.5 vs. MTT: 24.7; p < 0.001), while the RISC II Score showed no significant differences (STT: 20.0 vs. MTT: 17.1; p = 0.241). Preclinical data revealed a higher intubation rate, more chest tube insertions and a higher use of catecholamines in the STT group (p < 0.05). Clinically, we found significant differences in the duration of invasive ventilation (STT: 7.3d vs. MTT: 5.4d; p = 0.001) and ICU stay (STT: 12.3d vs. MTT: 9.4d; p < 0.001). While the complication rate was higher for the STT group (sepsis (STT: 11.4% vs. MTT: 5.7%; p = 0.017); lung failure (STT: 23.7% vs. MTT: 12.3%; p = 0,001)), neither the non-adjusted lethality rate (STT: 13.2% vs. MTT: 13.7%; p = 0.493) nor the Standardized Mortality Ratio (SMR) showed significant differences (STT: 0.66 vs. MTT: 0.80; p = 0.397). The multivariate regressive analysis confirmed that severe thoracic trauma is not an independent risk factor for lethality in our patient cohort. Conclusion: Despite a higher injury severity, the extended need of emergency measures and a higher rate of complications in injured patients with severe blunt thoracic trauma, no influence on lethality can be proved. The reduction of the complication rate should be a goal for the next decades

Iliac Bone Corridors to Host the Transiliac Internal Fixator—An Experimental CT Based Analysis

Background: The transiliac internal fixator (TIFI) is a novel minimally invasive surgical procedure to stabilize posterior pelvic ring fractures. Two bone corridors with different lengths, widths, and angulations are suitable to host screws in the posterior iliac wing. While the length and the width have been described previously, the angulation has not been determined yet. Methods: We created a computer tomography-based 3D-model of 40 patients (20 women, 20 men). The possible bone corridors to host the ilium screws for the TIFIcc (cranio-caudal) and the TIFIdv (dorso-ventral) procedure were identified. After reaching the optimal position, the angles in relation to the sagittal and axial plane were measured. The anterior pelvic plane was chosen as the reference plane. Results: The mean angle of the TIFIcc screws related to the axial plane was 63.4° (±1.8°) and to the sagittal plane was 12.3° (±1.5°). The mean angle of the TIFIdv screws related to the axial plane was 16.1° (±1.2°) and to the sagittal plane was 20.1° (±2.0°). In each group, a high constancy was apparent irrespective of the age or physical dimension of the patient, although a significant gender-dependent difference was observed”. Conclusions: Due to a high inter-individual constancy in length, width, and angulation, bone corridors in the posterior iliac wing are reliable to host screws for posterior pelvic ring fixation irrespective of each individual patient’s anatomy