Wall Stability Research Articles

3D Physical Experimental Study of Shield–Strata Interaction Under Dynamic and Static Disturbance

With the increasing depth and intensity of coal mining, there is an increasing risk to the working face due to high static load and periodic breakage of the roof. The relation between the support and the surrounding rock under static–dynamic coupling loading disturbance is an important factor affecting the stability of the working face. In this study, a 3D physical modeling platform is developed to study the interaction between the shield and strata under dynamic and static disturbance. In the experiment, the static load is set to 0, 0.5, 1, and 2 MPa, respectively. The different dynamic load is realized by changing the fall height of the iron plate. The change in hydraulic support resistance is recorded by the pressure monitoring system. The displacement of the coal wall is monitored by using an infrared rangefinder. The results show that the change in static load and dynamic load will affect the support resistance and coal wall displacement. With the increase in dynamic load, coal wall displacement, and bracket resistance increase, the increase is not linear. The larger the dynamic load, the greater the increase. Static load change has little effect on bracket resistance, and the impact on coal wall displacement is large. With the increase in static load, coal wall displacement is reduced and then increased. In static load, for the stability of coal wall, there is a threshold; below the threshold, the static load can improve the stability of coal wall, exceed the threshold, but accelerate the destruction of coal wall. At the same time, the stability coefficient of the quarry bracket and surrounding rock is defined. The sensitivity analysis of the main parameters is carried out. The method of controlling the stability of the quarry bracket and surrounding rock is proposed.

ELEMENT UP TO STRUCTURE MODELING WALL SHEET PILE WITH STEEL STRUTTING REINFORCEMENT IN FOUNDATION EXCUREMENT

<p>Evaluation modelling of the OT-22 steel sheet pile wall with type H-350 steel strutting reinforcement in the excavation for the foundation structure with a depth of 7.50 meters was carried out to get the value of the safety factor and wall stability. The evaluation stages include subgrade investigation using the SPT method, data collection of profile steel properties used, interpretation of soil data, staged-construction modeling using the Finite Element Method (FEM) computer application, and analysis of modeling results. From the research that has been done, the value of maximum bending moment (M<sub>max</sub>) is 223.8 kNm/m', the magnitude of the axial force that occurs in the strut members is 22.51 kN, 121.91 kN, and 66.10 kN respectively. The value of maximum lateral displacement (U<sub>x</sub>) is 62.4 mm. From these results, it can be concluded that the lateral displacement (U<sub>x</sub>) that occurs is much larger than allowable displacement (U<sub>all</sub>) 39 mm. Thus, it is necessary to modify the existing sheet pile wall system, such as to change the dimensions of the steel sheet pile, changing the dimensions of the steel strutting, or changing the distance of the steel strutting.</p>

Research on Factors Affecting Mine Wall Stability in Isolated Pillar Mining in Deep Mines

This study takes the Dongguashan Copper Mine as its engineering background. Based on the mechanical model of the mine wall under the trapezoidal load of the backfill, a comprehensive evaluation index is proposed, and its calculation equation is derived. On this basis, an orthogonal test is designed to explore the influence of mining design parameters on mine wall stability. The results show that the width of the mine wall is the main factor affecting its stability, and increasing the width of the mine wall can significantly improve its stability. When the width of the mine wall is kept above 4 m, its stability is better. When the mechanical parameters of the backfill are poor, the mine wall is prone to overturning failure. The width of the mine room has an influence on the multi-directional loading of the mine wall, but the influence on the stability of the mine wall is low. According to the regression equation calculation, the mine wall safety factor is about 1.46 under the design of G5 mining of Dongguashan Line 52, the stability of the mine wall is good after actual mining and the engineering application effect is ideal, which can provide a theoretical basis for the design of isolation pillar mining in deep mines.

Identification of Candidate Genes Associated With Tolerance to Apple Replant Disease by Genome-Wide Transcriptome Analysis.

Apple replant disease (ARD) is a worldwide economic risk in apple cultivation for fruit tree nurseries and fruit growers. Several studies on the reaction of apple plants to ARD are documented but less is known about the genetic mechanisms behind this symptomatology. RNA-seq analysis is a powerful tool for revealing candidate genes that are involved in the molecular responses to biotic stresses in plants. The aim of our work was to find differentially expressed genes in response to ARD in Malus. For this, we compared transcriptome data of the rootstock ‘M9’ (susceptible) and the wild apple genotype M. ×robusta 5 (Mr5, tolerant) after cultivation in ARD soil and disinfected ARD soil, respectively. When comparing apple plantlets grown in ARD soil to those grown in disinfected ARD soil, 1,206 differentially expressed genes (DEGs) were identified based on a log2 fold change, (LFC) ≥ 1 for up– and ≤ −1 for downregulation (p < 0.05). Subsequent validation revealed a highly significant positive correlation (r = 0.91; p < 0.0001) between RNA-seq and RT-qPCR results indicating a high reliability of the RNA-seq data. PageMan analysis showed that transcripts of genes involved in gibberellic acid (GA) biosynthesis were significantly enriched in the DEG dataset. Most of these GA biosynthesis genes were associated with functions in cell wall stabilization. Further genes were related to detoxification processes. Genes of both groups were expressed significantly higher in Mr5, suggesting that the lower susceptibility to ARD in Mr5 is not due to a single mechanism. These findings contribute to a better insight into ARD response in susceptible and tolerant apple genotypes. However, future research is needed to identify the defense mechanisms, which are most effective for the plant to overcome ARD.

Multiscale simulations suggest a protective role of neo-adventitia in abdominal aortic aneurysms

Abdominal aortic aneurysms (AAAs) are a dangerous cardiovascular disease, the pathogenesis of which is not yet fully understood. In the present work a recent mechanopathological theory, which correlates AAA progression with microstructural and mechanical alterations in the tissue, is investigated using multiscale models. The goal is to combine these changes, within the framework of mechanobiology, with possible mechanical cues that are sensed by vascular cells along the AAA pathogenesis. Particular attention is paid to the formation of a ‘neo-adventitia’ on the abluminal side of the aortic wall, which is characterized by a highly random (isotropic) distribution of collagen fibers. Macro- and micro-scale results suggest that the formation of an AAA, as expected, perturbs the micromechanical state of the aortic tissue and triggers a growth and remodeling (G&R) reaction by mechanosensing cells such as fibroblasts. This G&R then leads to the formation of a thick neo-adventitia that appears to bring the micromechanical state of the tissue closer to the original homeostatic level. In this context, this new layer could act like a protective sheath, similar to the tunica adventitia in healthy aortas. This potential ‘attempt at healing’ by vascular cells would have important implications on the stability of the AAA wall and thus on the risk of rupture. Statement of significanceCurrent clinical criteria for risk assessment in AAAs are still empirical, as the causes and mechanisms of the disease are not yet fully understood. The strength of the arterial tissue is closely related to its microstructure, which in turn is remodeled by mechanosensing cells in the course of the disease. In this study, multiscale simulations show a possible connection between mechanical cues at the microscopic level and collagen G&R in AAA tissue. It should be emphasized that these micromechanical cues cannot be visualized in vivo. Therefore, the results presented here will help to advance our current understanding of the disease and motivate future experimental studies, with important implications for AAA risk assessment.

Seismic behavior of tiered geogrid reinforced soil (GRS) using treated backfill soil

As the use of geogrid reinforced soil (GRS) walls increases, appropriate solutions should be considered to improve their performance. In recent years, wall construction in the multi-tiered configuration has improved both static and post-earthquake behavior, and become an appropriate approach to building high-reinforced soil walls. In addition to the above approach, treatment of the soil used as the wall backfill is also a suitable solution to enhance the wall performance. In this study, a combination of the two above concepts has been employed for better understanding the GRS wall behavior by developing a series of reduced-scale physical models. One-meter-high models in one- and multi-tiered fashion were tested backfilled with untreated and treated (by adding a combination of cement and polypropylene fibers) silty sand mixture. A comparison of the 1g shaking table tests among wall models subjected to seismic waves indicated the influence of the treating solutions on the dynamic response of the walls. The findings suggest that use of the two proposed approaches in the GRS walls construction has a notable effect on the wall stability after construction and during an earthquake. It also improves the essential seismic parameters such as displacement and acceleration responses.

Wellbore Stability Analysis of Horizontal Wells for Shale Gas With Consideration of Hydration

Abstract With the wide application of extended reach wells and horizontal wells, the geological conditions faced during the drilling process have become increasingly complicated, and the resulting wellbole collapse problem has become serious. Based on an L-1 horizontal well, this study provides a method for calculating collapse pressure considering the influence of formation hydration. This method is used to obtain the stress distribution around the well and collapse situation at 4100 m underground. The wellbore stability can be evaluated by the method. The factors affecting the stress and collapse of the well are analyzed by changing the construction parameters and geological parameters. Studies have shown that the rock near the well has collapsed to a certain extent and shale hydration increases the formation Poisson's ratio, resulting in more serious collapse. The study also found that hydration, drilling fluid density, and borehole size have the greatest impact on the stability of the borehole wall, followed by the well deviation angle, and the bedding angle the least. Carefully exploring the situation of the shale gas reservoir in the drilling design stages, considering the impact of hydration, and selecting appropriate construction parameters are necessary to avoid the collapse of the shaft wall and affect the shale gas production process. This study can provide a reference for ensuring the stability of the wellbore.

Intervention mechanism of self-degradation of ready-to-eat sea cucumber by adding green tea extract and gallic acid

Gallic acid (GA) and green tea extract (GT) could retard the self-degradation of ready-to-eat sea cucumber (RSC). The physical and chemical properties of RSC were changed after cross-linking. Cross-linkers could retard the conversion of α-helix like structure to random coil. Besides, the peptides of cross-linked RSC were easily broken at the sites of G, E, A, L, S, H, Y, V and I after stored for 30 d. The self-degradation rate of RSC before and after cross-linking was determined by synthetic typical peptides. After cross-linked by GA, the relative peak heights of NQ, NL and GLQ increased by 20.59%, 11.14% and 31.49%, indicating that GA could effectively retard the degradation of the peptides during storage. Moreover, hydrogen bond was confirmed as the main force to maintain the stability of RSC body wall before and after cross-linking.

The Shear Damage Model of the Two-Component Forming Polymer Grouting Material-Bentonite Contact Surface

The newly developed two-component polymer (TFPU) cut-off walls have great application potential in civil engineering for water-seepage prevention. Investigating the mechanical interactions between TFPU and soil from the theoretical perspective can provide a basis for furtherly evaluating the stability of TFPU cut-off walls, which, however, has not been conducted. In this study, based on the shear testing results, the shear damage model of the TFPU-bentonite contact surface was established. Studies show that the TFPU-bentonite contact surface performs strain-softening behavior under shear and that the strain-softening behavior becomes less and less obvious when the normal stress increases. The theoretical shear stress-strain curves are in good consistent with the experimental ones, and the maximum differences between the theoretical shear stress and shear strain at yield and the experimental ones are about 3.88% and 3.40%, respectively, indicating that the shear damage model can reflect the mechanical properties of the TFPU-bentonite contact surface. The critical damage of the contact surface increases from 0.05 to 0.50 in the power function way when normal stress increases from 75 to 1200 kPa, implying that the shear failure of the contact surfaces changes from brittleness to ductility. This study provides a theoretical base for evaluating the influences of the TFPU-soil contact surface on the stability of the TFPU cut-off wall structures.

Chest wall reconstruction in a young man after high-velocity gunshot using a combination latissimus dorsi flaps and titanium plates: A case report.

Chest trauma, penetrating or blunt, is common in this era of road traffic accidents, terrorism, and hunting in Iraq. During the last decade, many novel surgical procedures and materials were used to reconstruct or stabilize the chest wall to improve integration, maintain the stability of the chest wall, and reduce infections. However, no precise guidelines for managing chest wall diseases are still available to date. Here, we present a 24-year-old male who underwent chest wall reconstruction using a combination of latissimus dorsi flap and titanium plates, which were to cover the chest wall after a high-velocity gunshot. This patient was in shock too, with a lung contusion and massive hemorrhage. The sucking open chest wound lead to grossly disturbed respiratory mechanics. Such patients usually die on the way due to hemodynamic instability. In this particular case, adequate resuscitation and prompt thoracotomy saved the patient's life. This case report is important because, as we already mentioned, thoracic trauma alone is the cause of death in 25% of patients, and in another 25%, it's a contributing factor in a polytrauma death. This amounts to very high mortality. Our patient received a major laceration of the left lung. Our patient had a full recovery from this life-threatening situation.

Notoginsenoside as an environmentally friendly shale inhibitor in water-based drilling fluid

The demand for non-toxic and biodegradable shale inhibitors is growing in the drilling industry. In this paper, the effect of notoginsenoside (NS) as a new, environmentally friendly inhibitor of shale hydration is systematically studied for the first time. The inhibition performance of NS was evaluated via inhibition evaluation tests, including mud ball immersion tests, linear expansion tests, shale rolling recovery tests, and compressive strength tests. The inhibition mechanism of NS was analyzed using Fourier transform infrared spectroscopy (FTIR), contact angle measurements, particle size distribution determination, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The experimental results demonstrate that NS is able to adhere to the clay surface, forming a hydrophobic film that prevents the entry of water molecules and inhibiting the hydration dispersion of the clay. Because of this, NS can maintain the original state of bentonite pellets in water, which can effectively reduce the swelling rate of bentonite, increase the recovery rate of shale drill cuttings, maintain the strength of the shale, and therefore maintain the stability of the borehole wall during drilling. In addition, NS is non-toxic, degradable, and compatible with water-based drilling fluids. The above advantages make NS a promising candidate for use as an environmentally friendly shale inhibitor.

Mechanical Properties of Loess and Filling Materials of High-Speed Railway Vibration Isolation Trench in Loess Area

The special properties of loess make its impact on the vibration propagation of high-speed railways different from other soils. In this study, the static and dynamic characteristics of loess were studied by static and dynamic triaxial tests. The experimental results show that when the frequency is the same, the dynamic stress-strain relationship curve moves up with the increase of the confining pressure. The frequency has little effect on the initial tangential dynamic modulus of the undisturbed loess. we studied the static and dynamic characteristics of loess and discussed the implementation methods of viscoelastic artificial boundary and infinite element boundary in high-speed rail dynamic response analysis. The vibration reduction and isolation effect of the trench with different filling materials (the concrete, gypsum, foamed plastic, and rubber) was studied. The results show that the comprehensive performance of the foamed plastics is better from the perspective of durability and stability of the vibration isolation trench wall. The research results can provide a reference for the selection of filling materials for high-speed railway vibration isolation trench in loess area.

P118. RECONSTRUCTION OF STERNAL NONUNION USING THE STERNAL TALON SYSTEM; AN 11-YEAR EXPERIENCE

PURPOSE: Closure after sternotomy is frequently performed with wiring. In patients with sternal nonunion, the Sternal Talon (KLS Martin Group) may achieve bony union more predictably without relying on transosteal hardware in unhealthy bone for osteosynthesis. METHODS: An IRB-approved review was conducted of all patients undergoing Sternal Talon reconstruction by the senior author between 2010-2021. Patient comorbidities, reconstructive indication, and surgical history was reviewed. Nonunion classification, number of Talon devices utilized and concurrent procedures were recorded. Outcomes included pain relief postoperatively, chest wall stability, and evidence of sternal union, assessed using standard summary statistics. RESULTS: 22 patients (ages 49-83) underwent ORIF using the Sternal Talon for sternal nonunion in all but 2 patients with a nickel allergy precluding wiring. Index cardiac procedure included: CABG (77%), valve replacement (18%), and heart transplant (5%). 1-4 Talons were used: 1 (13.6%), 2 (22.7%), 3 (50%), 4 (13.6%). All patients presented with sternal pain/instability, 2 had failed conventional ORIF. Average time to Talon ORIF was 12.6 +/- 11.8 months. At an average of 15.1 +/- 15 months follow-up, sternal union was present in 100% of patients and 91% demonstrated relief of pain/instability. 2 wound infections & 1 hematoma occurred. 3 patients required prominent hardware removal. CONCLUSION: The Sternal Talon device represents a reliable method of achieving sternal union in high-risk patients with an acceptable side effect profile.

PpePL1 and PpePL15 Are the Core Members of the Pectate Lyase Gene Family Involved in Peach Fruit Ripening and Softening.

Pectin is the major component in the primary cell wall and middle lamella, maintaining the physical stability and mechanical strength of the cell wall. Pectate lyase (PL), a cell wall modification enzyme, has a major influence on the structure of pectin. However, little information and no comprehensive analysis is available on the PL gene family in peach (Prunus persica L. Batsch). In this study, 20 PpePL genes were identified in peach. We characterized their physicochemical characteristics, sequence alignments, chromosomal locations, and gene structures. The PpePL family members were classified into five groups based on their phylogenetic relationships. Among those, PpePL1, 9, 10, 15, and 18 had the higher expression abundance in ripe fruit, and PpePL1, 15, and 18 were upregulated during storage. Detailed RT-qPCR analysis revealed that PpePL1 and PpePL15 were responsive to ETH treatment (1 g L−1 ethephon) with an abundant transcript accumulation, which suggested these genes were involved in peach ripening and softening. In addition, virus-induced gene silencing (VIGS) technology was used to identify the roles of PpePL1 and PpePL15. Compared to controls, the RNAi fruit maintained greater firmness in the early storage stage, increased acid-soluble pectin (ASP), and reduced water-soluble pectin (WSP). Moreover, transmission electron microscopy (TEM) showed that cell wall degradation was reduced in the fruit of RNAi-1 and RNAi-15, which indicated that softening of the RNAi fruit has been delayed. Our results indicated that PpePL1 and PpePL15 play an important role in peach softening by depolymerizing pectin and degrading cell wall.

Evaluating the mechanical properties of anisotropic shale containing bedding and natural fractures with discrete element modeling

Natural fracture data from one of the Carboniferous shale masses in the eastern Qaidam Basin were used to establish a stochastic model of a discrete fracture network and to perform discrete element simulation research on the size effect and mechanical parameters of shale. Analytical solutions of fictitious joints in transversely isotropic media were derived, which made it possible for the proposed numerical model to simulate the bedding and natural fractures in shale masses. The results indicate that there are two main factors influencing the representative elementary volume (REV) size of a shale mass. The first and most decisive factor is the presence of natural fractures in the block itself. The second is the anisotropy ratio: the greater the anisotropy is, the larger the REV. The bedding angle has little influence on the REV size, whereas it has a certain influence on the mechanical parameters of the rock mass. When the bedding angle approaches the average orientation of the natural fractures, the mechanical parameters of the shale blocks decrease greatly. The REV representing the mechanical properties of the Carboniferous shale masses in the eastern Qaidam Basin were comprehensively identified by considering the influence of bedding and natural fractures. When the numerical model size is larger than the REV, the fractured rock mass discontinuities can be transformed into equivalent continuities, which provides a method for simulating shale with natural fractures and bedding to analyze the stability of a borehole wall in shale.

Design of reinforced cohesive soil walls accounting for wall facing contribution to stability

Where granular materials are not easily available, local cohesive soils are increasingly employed in geosynthetic reinforced soil walls as a cheap and sustainable option. Conventional design methods do not yet account for the beneficial effect of cohesion in reducing the amount of required reinforcement. Similarly, the contribution of the face to stability is rarely accounted for, despite plenty of experimental evidence in its favour. In this paper, a semi-analytical method based on limit analysis is developed for the design of reinforced soil walls in frictional–cohesive backfills accounting for the wall contribution. A parametric analysis was conducted to evaluate the effect of soil cohesion and friction angle, facing batter, block width, location of the reaction force acting on the face, facing–backfill interface friction, facing–foundation interface friction and reinforcement length. Dimensionless design charts providing the required amount of reinforcement for lengths recommended in design standards are provided for both uniform and linearly increasing reinforcement distributions. It emerges that accounting for the presence of cohesion and the facing element can lead to significant savings in the overall level of reinforcement, and that tension cracks can be particularly detrimental to wall stability for highly cohesive soils so they cannot be overlooked in the design.

Transcriptomic analysis of the mechanisms involved in enhanced antagonistic efficacy of Meyerozyma guilliermondii by methyl jasmonate and disease resistance of postharvest apples

The biological control ability of the yeast, Meyerozyma guilliermondii, in restaining Penicillium expansum infection in apples, has been reported to be enhanced by methy jasmonate (MeJA). Our previous research unveiled the possible physiological biocontrol mechanisms of the yeast; however, the related molecular mechanisms were unclear. This study aimed to investigate the possible molecular mechanisms behind the enhanced biological control efficacy of M. guilliermondii cultured with MeJA through transcriptomic approaches. The transcriptome analysis of MeJA cultured M. guilliermondii indicated that MeJA induced changes in oxidative stress response, energy metabolism, cell wall synthesis and stability and cell growth. Meanwhile, transcriptomic analysis of apples treated with M. guilliermondii and MeJA cultured M. guilliermondii was also investigated. Our results witnessed that MeJA cultured M. guilliermondii enhanced the cell wall synthesis, antioxidant activity, plant disease resistance, increased peroxisome proliferation, energy metabolism, phenylpropane metabolism and other pathways of apples. Expression levels of PPO, EXPA1, TFT6, GHR5, CYP73 and other genes were increased, which enhanced the apple's stability, antioxidant, stress resistance and energy metabolism. This study will provide a theoretical basis for improving the biocontrol efficacy of antagonistic yeast cultured with MeJA.

Study on the Synchronous Instability Mechanism of the Coal Wall and Direct Roof of High Soft Coal Seam

The advanced mining stress on a large working face can easily lead to the failure of the roof and coal mass; coal wall spalling and roof caving occur. The degree of coal wall failure and the depth of the plastic fracture zone are closely related to the advanced mining stress. The mechanical analysis model is established, and the stress distribution in the fracture and plastic zone is analyzed by the elastic-plastic theory, and the depth function expressions of two zones are determined. Comparative analysis of the factors affecting mining strength shows that the mining depth, mining height, and strength of coal are the key factors affecting the stability of the coal wall. The A1 coal of Zhangji mine in Huainan is soft and thick, and the direct roof is easily separated by the organic membrane, which is easy to form arc-shaped sliding instability. The increase in the unsupported roof area causes the direct roof caving and reduces its bearing capacity and stiffness. It is unable to provide enough support for the broken block of the overlying key stratum, which makes the broken block reverse rotation and further aggravate the roof fall; the synchronous instability of the coal wall and direct roof is formed.

Performance Comparison and Critical Finite Element Based Experimental Analysis of Various Forms of Reinforcement Retaining Structural System

Three-dimensional finite element analysis has been carried out in order to study the response of retaining walls subjected to lateral earth pressure using ABAQUS/CAE. This study consists of analysis and design of cantilever, gravity type, and precast concrete retaining wall. It also shows comparative study such as distribution of stresses along with the deflection throughout the height of the retaining walls. The mathematical analysis procedure is adopted that entails selecting dimensions to meet the requirements of several codes and then evaluating the stability of the entire whenever the backfill load works on the wall. The stability of retaining walls in terms of sliding and overturning is evaluated. The three specified walls are then investigated using the ABAQUS software, and their behaviour is studied. In this analysis process, two components of the formed concrete wall; one is a base plate and another component is a cantilever sandwich panel, were projected. A headed anchor joins the prefabricated cantilever wall to the base plate, keeping the slab and wall together while also maintaining their integrity in the specific positions. The system requires a unique construction method for final assembly. Mainly two steps were followed for analysis: first, the different components for shear and bending moments, namely, heel and footplates, were designed, and then, the stability of the whole structure under load was evaluated. The ABAQUS program was used to simulate and analyse the stability of various walls, including traditional and precast concrete retaining walls. It was found on the basis of the observation that the prefabricated retaining wall is the most viable option out of the three as the stress and deflection in the former type are lowered.

Operative versus non-operative management of rib fractures in flail chest after cardiopulmonary resuscitation manoeuvres.

OBJECTIVESBlunt chest trauma after mechanical resuscitation manoeuvres appears to have a significant impact on the often complicated course. Due to a lack of data in the literature, the purpose of this study was to investigate the feasibility and immediate outcome of chest wall stabilization for flail chest in this vulnerable patient population.METHODSWe retrospectively reviewed the medical records of patients after cardiopulmonary resuscitation between January 2014 and December 2018 who were diagnosed with flail chest. We attempted to compare patients after surgery with those after conservative treatment.RESULTSOf a total of 56 patients with blunt chest trauma after mechanical resuscitation and after coronary angiography, 25 were diagnosed with flail chest. After the exclusion of 2 patients because of an initial decision to palliate, 13 patients after surgical stabilization could be compared with 10 patients after conservative therapy. Although there was no significant difference in the total duration of ventilatory support, there was a significant advantage when the time after stabilization to extubation was compared with the duration of ventilation in the conservative group. The presence of pulmonary contusion, poor Glasgow Coma Scale score or the development of pneumonia negatively affected the outcome, but additional sternal fracture did not.CONCLUSIONSSurgical stabilization for chest wall instability is well tolerated even by this vulnerable patient population. Our results should be used for further randomized controlled approaches. It is necessary to evaluate the situation with all parameters in an interdisciplinary manner and to decide on a possible surgical therapy at an early stage if possible.