Ribbed Plate Research Articles

Bending of a ribbed plate under complex loading

The article considers the problem of a rectangular plate, supported by a cross system of stiffening ribs, bending. In addition to the transverse load, the plate is subjected to forces in its plane, transmitted through the ribs. Аn analytical solution to the boundary value problem for the resolving differential equation with respect to the normal deflection of the plate, describing the deformation of a rectangular plate supported by stiffeners, is obtained. The solution is presented in the form of series in combinations of regular and special discontinuous functions, which converge quickly and lead to a simple computational algorithm. The influence of the ribs is taken into account in the equation in the form of additional terms containing factors with a delta function. This approach allows us to get rid of a number of assumptions regarding the interaction of the plate with its reinforcing elements. The use of the apparatus of generalized functions when modeling objects of this type simplifies the boundary conditions (there are no conditions for conjugation of various structural elements), but at the same time the differential equations become more complicated. The problem is reduced to the so-called partially degenerate equations. Development of analytical methods that allow obtaining exact solutions of differential equations of this type, and their introduction into computational practice, is one of the urgent tasks of the mechanics of objects with disturbed regularity.

Surgical stabilization of rib fractures is associated with improved survival but increased acute respiratory distress syndrome

BackgroundHow the surgical stabilization of rib fractures after trauma affects the development of acute respiratory distress syndrome and impacts survival has yet to be determined in a large database. We hypothesized that surgical stabilization of rib fractures would not decrease the incidence of acute respiratory distress syndrome. MethodsThe National Trauma Data Bank was queried for all traumatic rib fractures in 2016. Patients were divided into groups with single rib fractures, multiple rib fractures, and flail chest. Nonoperative therapy was compared with stabilization of rib fractures of 1 to 2 ribs or 3+ ribs. ResultsThere were 114,972 total patients with rib fractures meeting inclusion criteria, with 5,106 (4.4%) having flail chest, 24,726 (21.5%) having single rib fractures, and 85,140 (74.1%) having multiple rib fractures. Those with flail chest (15.9%) were most likely to get rib plating in comparison to multiple rib fractures (0.9%) and single rib fractures (0.2%); P < .001. On logistic regression, surgical stabilization of rib fractures 1 to 2 ribs (odds ratio: 0.17, 95% confidence interval: 0.10–0.28) or 3+ ribs (odds ratio: 0.17, 95% confidence interval: 0.11–0.28), with nonoperative therapy as the reference was associated with survival. Variables associated with mortality included increasing age, male sex, increasing injury severity score, decreased Glasgow coma scale, requirement of transfusions, and hypotension on admission. Surgical stabilization of rib fractures 3+ ribs (odds ratio: 2.30, 95% confidence interval: 1.58–3.37) was associated with acute respiratory distress syndrome but not 1 to 2 ribs (odd ratio: 1.55, 95% confidence interval: 0.97–2.48). On logistic regression of only patients with flail chest, stabilization of rib fractures was associated with decreased mortality but not increased risk of acute respiratory distress syndrome. ConclusionThe increased risk of acute respiratory distress syndrome should be considered in the preoperative assessment for stabilization of rib fractures.

Transdiaphragmatic Chest Wall Herniation

The combination of traumatic simultaneous diaphragmatic rupture and chest wall herniation remains rare, with 42 cases of traumatic transdiaphragmatic intercostal hernia (TDIH) reported in the literature since 1946. An accurate count of cases is difficult to obtain, as TDIH nomenclature has been variable.1-5 Risk factors for traumatic TDIH are not well established. As these injuries are uncommon, best management techniques have yet to be established. Reported repair techniques include primary closure, closure with mesh, and implantation of prosthetic or autologous material. We present our single-center series of 7 patients, the largest reported to our knowledge, and discuss the challenges of repairing these difficult injuries. After obtaining institutional review board approval, data were abstracted from the electronic medical record on all adults who underwent evaluation and treatment for traumatic TDIH between July 2014 and January 2019. Of the 7 cases of traumatic TDIH, 6 patients developed TDIH secondary to cough; the seventh patient presented with chronic chest wall pain after an episode of heavy lifting. All patients were obese or overweight. Pain and a "popping sensation" were the most common presenting symptoms. All patients underwent operative intervention with primary repair of the diaphragm and suture approximation of the ribs. 3 patients had onlay mesh repair of the chest wall and/or abdominal wall. 1 patient had plating of his rib fracture. 3 patients had a recurrence of the intercostal portion of the hernia No patients have undergone reoperation thus far. While previously thought to more commonly occur on the left side due to the protective effects of the diaphragm,2 the majority in this series had right-sided injuries. Herniation through the ninth-10th interspace remains the most common location.4 Computed tomography imaging should be used for diagnosis and operative planning. It is best to manage these hernias acutely to re-establish normal anatomy. Mesh may be required in delayed reconstructions of if the chest wall cannot be re-approximated. Rib plating should be considered in cases of instability or flail. High rates of complications are not unexpected given the complicated and rare nature of the injury. Given the high rate of intercostal hernia recurrence, it is likely that mesh repair or should be more often used in the treatment of this injury.

Dynamic method for determining critical loads in the PRINS computer program

Relevance. Buckling analysis is important in the design of buildings and structures. It is used in various fields of engineering - mechanical engineering, aircraft and shipbuilding, civil engineering, etc. Until the second half of the twentieth century, mainly analytical methods of buckling were applied in practice. With the appearance of computers, numerical methods, in particular, the finite element analysis, began to prevail. Buckling analysis was implemented in programs of finite element analysis, such as NASTRAN, ANSYS, ABAQUS, ADAMS, DIANA, and others. In view of great responsibility, buckling analysis of structure should be carried out using at least two different programs. However, due to the high cost of software products, not all project organizations are able to have a number of programs. An alternative is to develop programs that can complete buckling analysis using several methods. This would increase the reliability and quality of calculation results. The PRINS computer program has opportunity for buckling analysis using two methods - static and dynamic. The aims of the work - to show the theoretical aspects and practical implementation of the dynamic principle of buckling analysis in buildings and structures using finite element method, as well as to give the algorithm implemented in the PRINS program and the results of verification calculations confirming its reliability. Results. The algorithm presented in this article and implemented in the PRINS computer program allows to determine critical loads using a dynamic buckling criterion. On the basis of numerous verification calculations, it was established that the implemented algorithm was effective for determining critical loads in frame, thin-walled and ribbed plate structures. The use of the PRINS computer program enables to use an alternative method for determining critical loads for a wide class of engineering problems in addition to the classical (static) method.

CFD simulation of liquid desiccant dehumidifier performance with smooth and rough plates

Liquid film pattern is crucial for mass transfer performance of falling film liquid desiccant dehumidifier (LDD). Rough plate may be effective on modifying the liquid film pattern and then enhance dehumidification efficiency of the LDD. Therefore, this study aims to investigate unsteady gas-liquid flow and dehumidification performance of falling film LDD for smooth and rough plates. The gas-liquid flow was predicted by the RNG k-ε turbulence model while the interface patterns were tracked by volume of fluid (VOF) model. The dehumidification performance was simulated by user-defined function (UDF) codes based on the penetration theory. The dynamic liquid film characteristics, the gas-liquid flow fields, the mass fraction fields and dehumidification enhancement mechanisms were analyzed and discussed. Moreover, the effects of inlet air velocity and inlet desiccant concentration on the mass transfer characteristics were investigated. The results showed that the ribbed plate can induce liquid film waves and significantly enhance dehumidification performance of the falling film LDD. The dehumidification enhancement can reach 30.9% by the rough plate when inlet air velocity is 0.5 m s −1 and inlet desiccant concentration is 30%, compared with the smooth plate case. The enhancement mechanisms of dehumidification by the rough plate include the liquid film waves, the flow vortex and high-value TKE near the gas-liquid interface. The outlet mass fraction of water vapor is decreased when the inlet air velocity is lower and the inlet desiccant concentration is higher. The rough plate is effective for the mass transfer enhancement for different inlet air velocity and desiccant concentration.

Sternal Resection and Reconstruction for Solitary Plasmacytoma of the Sternum

A 63-year-old patient was admitted with a sternal fracture and mass. On evaluation, most of the body of the sternum had been destroyed by a tumor. Radical resection of the sternum was performed and part of the major pectoral muscles adherent to the sternal tumor was also resected. The chest wall defect was reconstructed with mesh, bone cement, and a titanium rib plate system. Reconstruction with this method seemed to be an appropriate procedure to prevent instability of the chest wall.

Heat transfer augmentation of heated block surfaces in a turbulent flow channel by a slotted ribbed plate

This numerical study performed the three-dimensional simulations to explore the turbulent thermal flow characteristics over the heated blocks inside a square channel by a slotted ribbed plate through the RNG turbulence model and SIMPLE-C algorithm. The influence of slotted ribbed plate on the enhancement of turbulent heat transfer from these heated block surfaces would be evaluated through varying the pitch ratio of rib (1.2, 0.8, and 0.6) and the streamwise locations of slotted ribbed plate (before the left side of first heated block, x = 130 mm; aligned with the left side of first heated block, x = 150 mm; after the left side of first heated block, x = 170 mm) under different Reynolds numbers (5000, 6500, 8000, and 9500). The results of numerical analyses reveal that the slotted ribbed plate placed above the heated blocks can effectually augment the heat transfer. In addition, these slots can induce the local fluid flow bursts along the surfaces of the blocks and modify flow interaction between the ribs and blocks on a channel. The slotted ribbed plate aligned with the left side of first heated block can lead to greater overall-mean Nusselt number than the other locations. As compared to C0 (without plate), C5 (the slotted ribbed plate of 0.8 pitch ratio located at x = 150 mm) brings the maximum enhancement ratio of the overall-mean Nusselt number about 1.57 at Re = 9500. Under considering the friction through the channel, C7 (the slotted ribbed plate of 0.6 pitch ratio located at x = 130 mm) gains the best thermal performance factor about 1.45 at Re = 5000.

Plate of ribs: single institution’s matched comparison of patients managed operatively and non-operatively for rib fractures

BackgroundRib fractures are associated with significant morbidity and mortality in polytraumatized patients. There is considerable variability in the management (operative vs. non-operative) and timing of operative intervention. Although Eastern Association for the Surgery of Trauma (EAST) guidelines recommend early operative intervention in patients with flail chest, there are no strong recommendations regarding operative fixation in patients with a non-flail chest rib fracture pattern.MethodsWe reviewed our Trauma Quality Improvement Program database for patients aged 18 to 99 who underwent operative intervention of ribs from January 2016 to July 2019. We examined hospital length of stay (LOS), intensive care unit (ICU) LOS, ventilator days, Injury Severity Score, age, discharge disposition and packed red blood cell transfusions. Similarly, we collected data from patients aged 18 to 99 who had one or more rib fractures in this time frame. We compared results in a 4:1 ratio of patients managed non-operatively to patients managed operatively. The patient groups were matched based on age, number of rib fractures and presence of bilateral rib fractures.ResultsBetween January 2016 and July 2019, 33 of 4189 total patients diagnosed with rib fractures underwent operative fixation; the matched non-operative group consisted of 132 patients. The statistically significant differences included presence of bilateral rib fractures, displaced rib fractures and flail chest segments. The median ICU days were longer in the operative group (6.0 vs. 3.5 days). A subgroup analysis of patients without flail segments demonstrated a significant presence of displaced rib fractures.Our single-institution matched comparison of outcomes in operative intervention versus Non-operative Management (NOM) of rib fractures found an increased median number of ICU days. Patients who underwent operative intervention often stayed in the ICU preoperatively and postoperatively for aggressive pulmonary hygiene and pain control, suggesting observer bias. The increased incidence of displaced rib fractures and the presence of a flail segment in the operative group demonstrate congruence with EAST guidelines. A subgroup analysis of patients without flail segment did not demonstrate differences in outcomes nor shoulder girdle injury characteristics.Level of evidenceThis article presents level III evidence that can be used by other clinicians to analyze eligibility for patients to undergo surgical stabilization of rib fracture (SSRF) and to provide counterarguments for performing SSRF in a heterogenous group of patients.

Experimental Study on the Seismic Performance of Steel H-Shaped Beam-to-Column Connections

In terms of the moment frame system of steel structures, early brittle fractures developed in the H-shaped beam-to-column connection during the Northridge and Kobe earthquakes, thereby indicating insufficient seismic performance of these components. In this study, experiments were conducted on two-side shear connections of web and rib plate reinforcements of the flanges on an H-shaped beam-to-column connection. According to the test results, the H-shaped beam-to-column connections with two-side shear connections of beam web and rib plate reinforcements of the flanges were superior to the existing connections in terms of initial stiffness, energy dissipation capacity, and plastic rotational capacity. The test values exceeded 4.2%, 0.027 rad, and 125% in terms of story drift ratio, total plastic rotation capacity, and full plastic moment of the beam, respectively. Accordingly, the proposed H-shaped beam-to-column connection showed better performance than that of the intermediate moment frame regarding seismic design.

Clinical Application and Mechanical Analysis of the Treatment of Multiple Rib Fractures and Flail Chest Using Three-wings Rib Plate

This research evaluated the clinical efficacy of three-wings rib plate in the treatment of multiple rib fractures and flail chest with mechanical analysis and clinical verification. The model of rib and three-wings rib plate was reconstructed. The contact simulation with pretension stress was applied to the plate's fixation, and it was found that the bearable stress of the rib fractures after fixation increased from the result which indicated a good fixation efficacy of the plate. Clinical data of 53 cases of rib fractures and flail chest treated with three-wings rib plate in Shanghai Pudong Hospital of Fudan University were retrospectively analyzed. After the operation, the pain of the patients was relieved. Postoperative CT reconstruction of the chest showed good restoration of the rib fractures, which verified the clinical efficacy of three-wings rib plate. The three-wings rib plate showed a high value in clinical use for treatment of rib fractures.

Vertical rib plating for the treatment of slipping rib syndrome

BackgroundSlipping rib syndrome (SRS) is a painful condition of hypermobile, detached lower costal cartilages impinging the intercostal nerves. While surgical resection of the cartilaginous rib is reported as definitive treatment, recurrent symptoms are common. We describe the addition of vertical bioabsorbable rib plating to decrease recurrence. MethodsAn IRB-approved (#17-098), single institution, retrospective chart review was performed for patients who presented with SRS from 2009 to 2019 at a single institution. Descriptive statistics were used to compare patients with and without bioabsorbable vertical plating. ResultsA total of 85 patients (71.8% female, mean age 17.7 years) underwent evaluation for SRS. Of the 70 who underwent surgery solely for SRS, 29 (41%) underwent vertical rib plating at initial surgery while 41 (58.6%) did not. Recurrent symptoms developed in 7 (17.1%) unplated patients, while only 1 (3.4%) plated patient had recurrent SRS (which occurred after a motor vehicle crash) (p = 0.0116). Of the 8 with recurrent symptoms, 3 underwent vertical plating at a subsequent operation. ConclusionRate of recurrent symptoms after cartilage resection alone for SRS was 17.1%. The addition of vertical rib plating with bioabsorbable plates decreased recurrent symptoms and improved outcomes. Level of evidenceII.

Crashworthiness study of circular tubes subjected to radial extrusion under quasi-static loading

A structure of circular tubes subjected to radial extrusion with variable geometrical configurations was analysed. In a quasi-static experiment, axial grooves were produced on the circular aluminium tube under the action of indenters, without buckling instability. The energy was absorbed by plastic deformation of the aluminium tube and friction between parts. Deformation and driving force–displacement responses of the circular tube were analysed by way of numerical simulation, which matched the experimental results. Based on the validated finite element (FE) model, the effects of different geometrical configurations on structural crashworthiness were analysed. The results showed that, throughout the deformation stage, a lag was found in force changes in response to the increasing spacing between the aluminium tube and a rib plate and decreasing inclination angle of the indenter. The plastic energy ratio exceeded 60%. The specific energy absorption (SEA) was separately improved by 59.11%, 265.10%, and 75.00% with the increase of the inclination angle and number of the indenters and the decrease of the distance between the indenter and the centre of the tube. The increase in width of the rib plate could not significantly enhance energy absorption effects in the structure. In addition, by utilising the complex proportional assessment (COPRAS) method, it was found that the aluminium tube T3.5 (with wall thickness T of 3.5 mm) exhibited the optimal structural configuration and the best crashworthiness. In conclusion, the use of thin-walled tubes subjected to radial extrusion provide a reference for the development of new energy absorbers.

A model for evaluating the biomechanics of rib fracture fixation

IntroductionHigh rates of morbidity and mortality following flail chest rib fractures are well publicized. Standard of care has been supportive mechanical ventilation, but serious complications have been reported. Internal rib fixation has shown improvements in pulmonary function, clinical outcomes, and decreased mortality. The goal of this study was to provide a model defining the biomechanical benefits of internal rib fixation. MethodsOne human cadaver was prepared with an actuator providing anteroposterior forces to the thorax and rib motion sensors to define interfragmentary motion. Cadaveric model was validated using a prior study which defined costovertebral motion to create a protocol using similar technology and procedure. Ribs 4–6 were fixed with motion sensors anteriorly, laterally and posteriorly. Motion was recorded with ribs intact before osteotomizing each rib anteriorly and laterally. Flail chest motion was record with fractures subsequently plated and analyzed. Motion was recorded in the sagittal, coronal and transverse axes. FindingsCompared to the intact rib model, the flail chest model demonstrated an 11.3 times increase in sagittal plane motion, which was reduced to 2.1 times the intact model with rib plating. Coronal and sagittal plane models also saw increases of 9.7 and 5.1 times, respectively, with regards to flail chest motion. Both were reduced to 1.2 times the intact model after rib plating. InterpretationThis study allows quantification of altered ribcage biomechanics after flail chest injuries and suggests rib plating is useful in restoring biomechanics as well as contributing to improving pulmonary function and clinical outcomes.

69-YEAR-OLD MALE WITH ENTRAPPED CHEST TUBE: COMPLICATION OF CPR

SESSION TITLE: Medical Student/Resident Critical Care Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Cardiopulmonary resuscitation (CPR) is a lifesaving intervention routinely performed in medical institutions. However, it is associated with multiple complications including rib fractures requiring thoracostomy tube (TT) insertion. Additionally, there is a paucity of evidence identifying complications of CPR with a TT present. Here we describe a case of a patient who had their TT break due to CPR. CASE PRESENTATION: A 69-year-old male presented as a level two trauma status post motor vehicle collision. His initial injury severity score was 29 with injuries including: left-sided rib fractures with flail segment of ribs 1-6, left hemopneumothorax, comminuted fracture of the left scapular body and spine, left clavicle fracture with emphysema and hematoma. The patient was admitted to the surgical intensive care unit with management including a thoracotomy for rib plating and evacuation of the hematoma. Preoperative imaging is shown in Figure 1. The patient underwent left posterolateral thoracotomy with open reduction and internal fixation of left ribs 3-7 with evacuation of subcutaneous hematoma and left hemothorax. A 28 French TT was placed in the left posterior apical position, and a curved 28 French TT was placed in the left posterior inferior position. A postoperative chest x-ray confirmed lung re-expansion (Figure 2). On post-operative day 1, the patient became hypoxic, hypotensive, and bradycardic leading to cardiac arrest. Advanced cardiac life support was initiated including CPR and epinephrine for eight minutes until return of spontaneous circulation was achieved. A chest x-ray post arrest was taken showing the rib plating was intact. On post-operative day 2, removal of the TT was attempted. The distal portion of the left TT broke and remained within the thoracic cavity. A computed tomography of the chest (Figure 3) showed the broken portion of the tube. On post-operative day 3, the patient underwent left mini thoracotomy, removal of the retained TT under ultrasound guidance, and replacement of the apical TT. The distal end of the curved chest tube was found to be entrapped within the anterior rib fractures that resulted from CPR and successfully removed. The rest of the patient’s admission was unremarkable and he was discharged to a rehabilitation facility. DISCUSSION: To our knowledge this is one of the first cases to describe entrapment of a TT as a result of CPR. Additionally, this is one of the few cases to describe the use of a thoracotomy for removal of an entrapped tube. Thoracotomy has been reported as a management strategy in a similar case in which a nasogastric tube became entrapped intratracheally following lobectomy. There remains a paucity of data on the true incidence of abnormal positioning of tubes and the role of thoracotomy in the management of these patients. CONCLUSIONS: We present the case of a broken entrapped TT and successful removal via thoracotomy. Reference #1: Hoke RS, Chamberlain D. (2004). Skeletal chest injuries secondary to cardiopulmonary resuscitation. Resuscitation, 63(3):327-38. Reference #2: Deliliga A, Chatzinikolaou F, Koutsoukis D, Chrysovergis I, Voultsos P. (2009). Cardiopulmonary resuscitation (CPR) complications encountered in forensic autopsy cases. BMC Emergency Medicine, 28;19(1):23. DISCLOSURES: No relevant relationships by Jordan Debbrecht, source=Web Response No relevant relationships by Katherine Foerster, source=Web Response no disclosure on file for Brian Gilbert; No relevant relationships by Michael Nguyen, source=Web Response no disclosure on file for George Philip; No relevant relationships by William Waswick, source=Web Response

Dysrhythmia in traumatic RIB Fixation

IntroductionThe fixation of traumatic rib fractures with metallic plates has multiple benefits, especially in flail segments. These include reducing the number of ventilated and ICU days, the need for a tracheostomy, reduced incidence of pneumonia, and overall improvement in pain [1]. While the benefits have been defined, there have been a paucity of data in the reported medical risks of the procedure. At our institution, an anecdotally observed complication following the procedure included cardiac arrhythmia.MethodsA retrospective review of all patients sustaining acutely traumatic rib fractures undergoing operative fixation over a five-year period from March of 2015 to March of 2020 were included. A total of fifteen patients met criteria. All patients were confirmed to be in normal sinus rhythm preoperatively. Postoperatively, all patients were sent to the surgical ICU and continuously monitored for arrhythmia via telemetry. All arrhythmias identified were confirmed via twelve-lead electrocardiograms (EKG).ResultsNo patients had a history of arrhythmia preoperatively. Of the 15 patients, 11 (73%) [95% CI: 45-92%] were confirmed to have any arrhythmia postoperatively [Table 1]. Excluding sinus tachycardia, which may be attributable to a number of other perioperative factors, 8 (53%) patients [95% CI: 26-78%] were found to have experienced another arrhythmia as described above [Table 1].DiscussionThese results show that rib fixation carries a significant risk for perioperative cardiac dysrhythmia. Historical controls show the incidence of arrhythmia in non-cardiac, thoracic surgery to be between 17-30%, with atrial fibrillation accounting for the majority [2,3,4,5]. The total incidence of any arrhythmia after rib plating was 73%, which is significantly higher than the upper boundary (30%) of historical norms (p=0.0003) [Table 2]. Excluding sinus tachycardia, the incidence drops to 53% for rib plating, which still remains elevated above historical controls (p=0.05) [Table 2]. Multiple studies in cardiac surgery have proven preoperative antiarrhythmics effective in providing arrhythmia prophylaxis. Further investigation should be performed in arrhythmia prophylaxis in rib fixation. The fixation of traumatic rib fractures with metallic plates has multiple benefits, especially in flail segments. These include reducing the number of ventilated and ICU days, the need for a tracheostomy, reduced incidence of pneumonia, and overall improvement in pain [1]. While the benefits have been defined, there have been a paucity of data in the reported medical risks of the procedure. At our institution, an anecdotally observed complication following the procedure included cardiac arrhythmia. A retrospective review of all patients sustaining acutely traumatic rib fractures undergoing operative fixation over a five-year period from March of 2015 to March of 2020 were included. A total of fifteen patients met criteria. All patients were confirmed to be in normal sinus rhythm preoperatively. Postoperatively, all patients were sent to the surgical ICU and continuously monitored for arrhythmia via telemetry. All arrhythmias identified were confirmed via twelve-lead electrocardiograms (EKG). No patients had a history of arrhythmia preoperatively. Of the 15 patients, 11 (73%) [95% CI: 45-92%] were confirmed to have any arrhythmia postoperatively [Table 1]. Excluding sinus tachycardia, which may be attributable to a number of other perioperative factors, 8 (53%) patients [95% CI: 26-78%] were found to have experienced another arrhythmia as described above [Table 1]. These results show that rib fixation carries a significant risk for perioperative cardiac dysrhythmia. Historical controls show the incidence of arrhythmia in non-cardiac, thoracic surgery to be between 17-30%, with atrial fibrillation accounting for the majority [2,3,4,5]. The total incidence of any arrhythmia after rib plating was 73%, which is significantly higher than the upper boundary (30%) of historical norms (p=0.0003) [Table 2]. Excluding sinus tachycardia, the incidence drops to 53% for rib plating, which still remains elevated above historical controls (p=0.05) [Table 2]. Multiple studies in cardiac surgery have proven preoperative antiarrhythmics effective in providing arrhythmia prophylaxis. Further investigation should be performed in arrhythmia prophylaxis in rib fixation.

Оптимальне проектування ребристої плити

Оптимальне проектування ребристої плити

Band Gaps and Vibration Isolation of a Three-dimensional Metamaterial with a Star Structure.

Elastic metamaterials have promising applications in wave control and vibration isolation, due to their extraordinary characteristics, e.g., negative Poisson ratio, band gaps, effective negative mass density and effective negative modulus. How to develop new functional metamaterials using a special structure has always been a hot topic in this field. In this study, a three-dimensional (3D) star structure is designed to construct metamaterials with both negative static and dynamic properties. The results show that the 3D star structure formed a wide band gap at lower frequency and had a negative Poisson’s ratio. Different from conventional acoustic metamaterials, the main physical mechanism behind the low-frequency band gap of the 3D star structure is the resonance mode formed by the bending deformation of each rib plate, which made it easier to achieve effective isolation of low-frequency elastic waves with a low mass density. In addition, many structural parameters of the 3D star structure can be modulated to effectively adjust the band gap frequency by changing the angle between the concave nodes and aspect ratio. This study provides a new way to design the 3D acoustic metamaterials and develop the lightweight vibration isolation devices.

Precast monolithic coating of an industrial building based on variable-height beam-slabs

We consider the coatings of single-story industrial buildings of frame type, which in a typical solution are made in the form of a flooring of ribbed plates on rafters, trusses or arches. There is a high complexity of manufacturing, transportation and installation of structures and a large height of the coating. We offer truss beams-slabs of box-shaped cross-section, the height of which varies stepwise along the length, being limited by a square parabola at the top. Beams are installed on the substructure structures in a row, and between them on a permanent formwork of wooden boards are arranged monolithic sections of the plate. The calculation of deformations is performed taking into account the inelastic deformation of concrete and rebar in accordance with the recommended norms of state diagrams: three-line for concrete and two-line for rebar. The results of the calculation of a beam-plate with a span of 30 m, which has 5 different stages, the height of which is selected so that the required cross-section of the reinforcement remains constant along the entire length of the structure.

Current Status of Rib Plating: Hardware Failure When and How?

Surgical stabilization of rib fractures (SSRF) has been shown to decrease morbidity and mortality in patients with multiple rib fractures. This has led to a concomitant increase in the procedure, but the complications are just now being described in the literature. The purpose of this review is to focus on the current understanding of hardware failure after rib fixation. A recent study from the Chest Wall Injury Society (CWIS) found that hardware failure is relatively rare and often asymptomatic thus not requiring routine postoperative imaging or reoperation. When hardware failures occur, they tend to occur on the lateral and posterolateral columns. Patients who undergo fixation for chronic fractures may be at higher risk for complications. Hardware failure is a rare complication of SSRF and rarely requires reoperation. Postoperative imaging should be based on symptoms.

Rib Plating Offers Favorable Outcomes in Patients With Chronic Nonunion of Prior Rib Fractures

Although open reduction and internal fixation (ORIF) is an accepted treatment for a proportion of acute rib fractures, The literature on its potential to treat chronic, nonunion fractures is scarce. This study evaluates the outcomes and quality of life of patients who underwent ORIF for chronic, symptomatic, nonunion rib fractures. Thirty-two patients were explored for possible ORIF of nonunion rib fractures (≥6 months after injury). After excluding non-English-speaking patients (n= 1), those where no instability was noted at surgery (n= 3), and those deceased at the time of study (n= 4), 24 patients were eligible. Telephone interviews were conducted using a previously published rib fracture pain questionnaire. Seventy percent of eligible patients (19/24) consented and completed the questionnaire at a median of 55 months (interquartile range, 24-62) from surgery. Injuries were classified as multisystem trauma (n= 4) or isolated rib fractures (n= 15). The median pain severity (on a scale of 1 [none/mild] to 10 [severe]) significantly decreased from preoperatively (9; interquartile range, 7-10) to postoperatively (1; interquartile range, 0-2; P < .001). Most patients returned to daily activities, were able to work at their preinjury level, were satisfied with their surgery, and would undergo operative management again. Patients who underwent ORIF reported a significant decrease in fracture-associated symptoms and pain severity postoperatively. Most returned to daily activities, could work at preinjury levels, and were satisfied with surgery. ORIF should be considered as an option to help patients with symptomatic nonunion rib fractures.