Operative Costs Research Articles

A Systematic Review of Open, Laparoscopic, and Robotic Inguinal Hernia Repair: Management of Inguinal Hernias in the 21st Century

Background: In the 21st century, the management of groin hernias (GHs) has evolved from watchful waiting (WW) to robotic hernia repair (RHR). The present study interrogates the status of robotics in the context of current repairs and provides one author’s perspectives. Methods: A systematic review was undertaken using Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines for studies comparing open (OHR) to robotic hernia repair (RHR); RHR to laparoscopic hernia repair (LHR); or OHR vs. LHR vs. RHR. The historical context was extracted from previous reviews. Results: Fifty-four studies were included in the analysis. Three techniques have withstood the test of time: OHR (tissue and mesh repairs), laparo-endoscopic (TEP and TAPP), and RHR. The literature indicates that RHR is safe and effective for the management of groin hernias. Operative times and costs remain a concern when using this technique. While the number of overall complications with RHR is similar to OHR, in a minority of cases, complications are more consequential with the robotic platform. Conclusions: RHR has emerged as an unequivocally powerful technique for the management of GHs. OHR remains the technique of choice for local/regional anesthesia, posterior recurrences, and in centers that lack other platforms. In low- and middle-income countries, OHR is the most utilized technique. Centers of excellence should offer all techniques of repair including WW.

Optimization and Implementation Framework for Connected Demand Responsive Transit (DRT) Considering Punctuality

Demand Responsive Transit (DRT) is gaining attention as a flexible and efficient solution for connecting urban transit hubs, but challenges such as travel time variability and punctuality remain significant barriers. This study develops a robust optimization framework with variable travel speed to address these issues, minimizing user and operator costs while reducing transfer waiting times. The framework incorporates variable travel speeds and employs a genetic algorithm to optimize routes and operations compared to many studies using constant commercial speed. Experiments conducted in Hwaseong, South Korea, analyzed scenarios with varying service rates, vehicle capacities, and detour ratios. Results show that implementing punctuality-constrained DRT reduces total travel times by 14% compared to subways and 36% compared to buses, highlighting its potential to significantly improve user convenience and operational efficiency. The findings suggest that carefully designed DRT systems with highly reliable punctuality can enhance urban mobility by integrating seamlessly with existing transit networks, providing a cost-effective and reliable alternative to traditional public transport.

Increased stiffness with medial column screw supplementation of lateral locking plate for distal femur fractures: a biomechanical study.

We propose and assess the biomechanical stability of medial column screw supplementation in a synthetic distal femur fracture model. Twenty-four low density synthetic femora modeling osteoporotic, intraarticular distal femur fractures with medial metaphyseal comminution were split into two fixation groups: (1) lateral locking distal femur plate (PA- plate alone) and (2) lateral locking distal femur plate with a 6.5mm fully threaded medial cannulated screw (PWS- plate with screw). Cyclic biomechanical testing included 5 steps of 10,000 cycles with each step increasing axial loads starting at 0.5xBW (BW = 80kg) up to 2.5xBW. Discrete stiffness was calculated for each step and cumulative stiffness was calculated across the entire protocol. Outcomes of interest included cumulative stiffness, discrete stiffness, and instrumentation failure. Seven of the PA models had failure during testing. No failures were seen in the PWS group. PWS had 19.8% higher cumulative stiffness compared to PA (676.3 N/mm vs 809.8 N/mm; P = 0.014). Discrete stiffness showed < 1% differences at lower loads, but increasing loads found the PWS group with 12% greater discrete stiffness than the PA group (879.1 N/mm vs 983.8 N/mm; P = 0.028). This is the first study to evaluate the contribution of a medial column screw in a distal femur fracture model. PWS had superior stiffness and few failures compared to PA. Applied clinically, a medial column screw can increase construct stability in the setting of complex distal femur fractures with minimal increase in operative time, patient morbidity and cost.

Day-Ahead Two-Stage Bidding Strategy for Multi-Photovoltaic Storage Charging Stations Based on Bidding Space

Against the backdrop of a “dual-carbon” strategy, the use of photovoltaic storage charging stations (PSCSs), as an effective way to aggregate and manage electric vehicles, new energy sources, and energy storage, will be an important primary component of the electricity market. The operational characteristics of the aggregated resources within a PSCS determine its bidding space, which has an important influence on its bidding strategy. In this paper, a novel bidding space model is constructed for PSCSs, which dynamically integrates electric vehicles, photovoltaic generation, and energy storage. A two-stage bidding strategy for multiple PSCSs is established, with stage I aiming at achieving the lowest cost for the power purchased by a PSCS to optimize the power generation and power plan and stage II aiming at achieving the lowest cost of the grid operator’s power purchase to optimize the system’s power balance. Thirdly, the two-stage model is transformed into a single-layer, mixed-integer linear programming problem using dyadic theory and Karush–Kuhn–Tucker (KKT) conditions, enabling the derivation of the optimal bidding strategy. Finally, the example analysis verifies that the proposed model can achieve a reduction in the PSCS’s day-ahead power purchase cost and flexibly dispatch each resource within the PSCS to maximize revenue, as well as reducing power consumption behavior during peak tariff hours, to enhance the market power of the PSCS in the electricity market.

Synergistic learning with multi-task DeepONet for efficient PDE problem solving.

Multi-task learning (MTL) is an inductive transfer mechanism designed to leverage useful information from multiple tasks to improve generalization performance compared to single-task learning. It has been extensively explored in traditional machine learning to address issues such as data sparsity and overfitting in neural networks. In this work, we apply MTL to problems in science and engineering governed by partial differential equations (PDEs). However, implementing MTL in this context is complex, as it requires task-specific modifications to accommodate various scenarios representing different physical processes. To this end, we present a multi-task deep operator network (MT-DeepONet) to learn solutions across various functional forms of source terms in a PDE and multiple geometries in a single concurrent training session. We introduce modifications in the branch network of the vanilla DeepONet to account for various functional forms of a parameterized coefficient in a PDE. Additionally, we handle parameterized geometries by introducing a binary mask in the branch network and incorporating it into the loss term to improve convergence and generalization to new geometry tasks. Our approach is demonstrated on three benchmark problems: (1) learning different functional forms of the source term in the Fisher equation; (2) learning multiple geometries in a 2D Darcy Flow problem and showcasing better transfer learning capabilities to new geometries; and (3) learning 3D parameterized geometries for a heat transfer problem and demonstrate the ability to predict on new but similar geometries. Our MT-DeepONet framework offers a novel approach to solving PDE problems in engineering and science under a unified umbrella based on synergistic learning that reduces the overall training cost for neural operators.

Stop plan optimisation for three-pattern skip-stop schemes for urban rail transit systems

Mass rapid transit systems around the world are typically designed for all-stop operation schemes, in which train overtaking is not possible. To accelerate transit operation, the conventional A/B skip-stop scheme may be planned. This research explores alternative skip-stop schemes with three stop patterns, aiming to better match transit services with the spatial distribution of travel demand. The proposed generalised skip-stop operation model considers both the total cost of passengers and operator. A genetic algorithm is employed to solve the stop-plan optimisation problem, and a heuristic is tailored to determine an optimal dispatch headway for the respective stop plan. Based on computational experiments using synthetic data, the results suggest that skip-stop schemes have the potential to reduce total time costs by about 10%, particularly when there are structured demand concentrations, transit systems can operate safely with low time headway and short-distance demand is low. Although the total-cost saving of the best A/B skip-stop plan found is generally superior to those of other three-pattern skip-stop schemes, a three-pattern skip-stop scheme was found to offer a better total-cost saving in a scenario without short-distance travel demands. Overall, this research offers valuable insights into the potential benefits and limitations of different skip-stop schemes, contributing to a better understanding of their impact on passengers and operators.

A collaborative system of systems simulation of urban air mobility

Abstract The implementation of urban air mobility represents a complex challenge in aviation due to the high degree of innovation required across various domains to realize it. From the use of advanced aircraft powered by novel technologies, the management of the airspace to enable high density operations, to the operation of vertiports serving as a start and end point of the flights, urban air mobility paradigm necessitates significant innovation in many aspects of civil aviation as we know it today. To understand and assess the many facets of this new paradigm, a collaborative simulation is developed to holistically evaluate the system of systems through the modeling of the stakeholders and their interactions as per the envisioned concept of operations. To this end, models of vertiport air-side operations, unmanned/manned airspace management, demand estimation and passenger mode choice, vehicle operator cost and revenues, vehicle design, and fleet management are brought together into a system of systems simulation of urban air mobility. Through collaboration, higher fidelity models of each domain can be integrated into a single environment achieving fidelity levels not easily achievable otherwise. Furthermore, the integration enables the capture of cross-domain effects and allows domain-specific studies to be evaluated at a holistic level. This work demonstrates the collaborative simulation and the process of building it through the integration of several geographically distributed tools into an agent-based simulation without the need for sharing code.

Intercostal Nerve Cryoablation as an Effective Pain Management Strategy in the Nuss Procedure: Reducing Opioid Use and Hospital Stay.

Erector spinae plane (ESP) blocks, thoracic epidural, and patient-controlled analgesia (PCA) have all been used for perioperative pain management in the Nuss procedure without a consensus on what modality produces the best outcomes. Intercostal nerve cryoablation (INC) is a relatively new modality that involves freezing the nerves to prevent pain during recovery. Our hypothesis is that using INC for the Nuss procedure will decrease opioid use, pain scores, and length of stay (LOS) but will increase cost compared with ESP block, thoracic epidural, and PCA. This retrospective, observational study compared 108 patients who underwent the Nuss procedure at a pediatric acute care children's hospital in the southeast US. Patient charts were evaluated for significant differences in LOS, opioid use, and reported pain ratings based on type of analgesia administered: INC (n = 30), ESP block (n = 19), thoracic epidural (n = 41), and PCA (n = 18). Secondary variables included emergency department visits, readmissions, opioid refills, and various anesthetic and operative costs. Analysis of variance was performed on all outcome measures. Average LOS was significantly decreased in the INC group (2.9 days) compared with the thoracic epidural (4.7 days, p < 0.05) and the PCA groups (3.7 days, p < 0.05). Average cumulative opioid use was significantly decreased in the INC group (50.4 morphine milligram equivalents [MME]) compared with the thoracic epidural (117 MME, p < 0.05) and PCA groups (172.1 MME, p < 0.05). This study suggests that INC can be a viable and cost-effective option for reducing postoperative opioid consumption and LOS in Nuss procedure patients. Pain perception was lower in the INC group compared with the rest of the groups, except the epidurals, which were similar. However, the opioid consumption of the INC group was significantly lower than any other group. Despite the INC group having higher initial costs, it did not result in the highest total hospital charges, indicating its potential cost-effectiveness. There is a need for larger prospective randomized controlled trials to guide future research efforts.

Energetic and economic advantages of energy communities: a case study referred to a southern Italian town

Energy Districts and Communities are at the heart of EU programs. Nevertheless, several challenges are encountered when bringing into fruition. Their convenience is not fully understood on a small scale, due to the complexity of the start-up practices, which make them more suitable for commercial or industrial companies. In this scenario the present study arises, aimed at pointing out to small communities, at condominium scale, the economic benefits, in terms of Net Present Value (NPV), deriving from the adoption of the new community plant configurations. Such indicator gives a glance of the total cost, both investment and functioning ones, to be sustained during the plant life, together with the enjoyed benefits. Particularly the investment cost is presently a big obstacle to the spread of renewable energy systems whereas the high operative cost of conventional plants is less adequately considered. In this frame, through the paper the satisfaction of the electricity needs of the users of a building, sited in Reggio Calabria (Italy), when their plant configurations turn from single grid-connected into community is analyzed using 2024 tariffs. From the study the economic advantages of the community result, pointing out an NPV increase (€ 3798), with a consequent reduction of the investment pay-back time for most users. The benefit increases (€ 24,918) when an energy intensive user joins the community. The study also considers a plant configuration equipped with storage, pointing out the reduced grid exchanges: a lower injection of 5.6 MWh and a lower withdrawal of 6.9 MWh. Concerning NPV, despite the batteries cost and their replacement every 10 years, only low reductions are observed, thanks to the great saving obtained by stored energy, that make the investment convenient. In the future the study will be enriched with the analysis of plant configurations that consider aggregation among adjacent buildings.

Selective Leaching for the Recycling of Lithium, Iron, and Phosphorous from Lithium-Ion Battery Cathodes’ Production Scraps

The market for lithium iron phosphate (LFP) batteries is projected to grow in the near future. However, recycling methods targeting LFP batteries, especially production scraps, are still underdeveloped. This study investigated the extraction of iron phosphate and lithium from LFP production scraps using selective leaching, considering technical and economic aspects. Two leaching agents, sulfuric acid (0.25–0.5 M, 25 °C, 1 h, 50 g/L) and citric acid (0.25–0.5 M, 25 °C, 1 h, 70 g/L) were compared; hydrogen peroxide (3–6%vv.) was added to prevent iron and phosphorous solubilization. Sulfuric acid leached up to 98% of Li and recovered up to 98% of Fe and P in the solid residues. Citric acid leached 18–26% of Li and recovered 98% of Fe and P. Totally, 28% of Li was precipitated for sulfuric acid process, while recovery with citric acid did not produce enough precipitate for a characterization. Sulfur is the main impurity present in the precipitates. The total operative costs associated with reagents and energy consumption of the sulfuric acid route were below 3.00 €/kg. In conclusion, selective leaching provided a viable and economic method to recycle LFP production scraps, and it is worth further research to optimize Lithium recovery.

Cost-Effectiveness of Nonoperative Management vs Upfront Laparoscopic Appendectomy for Pediatric Uncomplicated Appendicitis Over 1 Year.

Non-operative management (NOM) with antibiotics alone for pediatric uncomplicated appendicitis is accepted to be safe and effective. However, the relative cost-effectiveness of this approach compared to appendectomy remains unknown. We aimed to evaluate the cost-effectiveness of non-operative versus operative management for pediatric uncomplicated acute appendicitis. A trial-based real-world economic evaluation from the healthcare sector perspective was performed using data collected from a multi-institutional non-randomized controlled trial investigating NOM versus surgery. The time horizon was 1 year, with costs in 2023 US dollars. Ratio of costs-to-charges (RCC)-based data for the initial hospitalization, readmissions, and unplanned emergency department visits were extracted from the Pediatric Health Information System (PHIS). Utility data were derived from patient-reported disability days and health-related quality-of-life scores. Multiple scenarios and one-way deterministic and probabilistic sensitivity analyses accounted for parameter uncertainty. Willingness-to-pay (WTP) threshold was set at $100,000 per quality-adjusted life year (QALY) or disability-adjusted life year (DALY). Primary outcome measures included total and incremental mean costs, QALY, DALY, and incremental cost-effectiveness ratios (ICERs). Of 1,068 participants, 370 (35%) selected NOM and 698 (65%) selected urgent laparoscopic appendectomy. Operative management cost an average of $9,791/patient and yielded an average of 0.884 QALYs while NOM cost an average of $8,044/patient and yielded an average of 0.895 QALYs. NOM was both less costly and more effective in base case and scenario analyses using disability days and alternate methods of calculating utilities. NOM is cost-effective compared to laparoscopic appendectomy for pediatric uncomplicated appendicitis over 1 year.

Bus scheduling with heterogeneous fleets: Formulation and hybrid metaheuristic algorithms

This paper focuses on optimizing mixed-fleet bus scheduling (MFBS) with vehicles of different sizes in public transport systems. We develop a novel mixed-integer nonlinear programming (MINLP) model to address the MFBS problem by optimizing vehicle assignment and dispatching programs. The model considers user costs, operator costs, and the crowding inconvenience of standing and sitting passengers. To tackle the complexity of the MFBS problem, we employ Genetic Algorithm (GA) and Grey Wolf Optimizer (GWO). Besides, we develop two hybrid metaheuristics, including GA-SA [a combination of GA and Simulated Annealing (SA)] and GWO-SA (a combination of GWO and SA), to improve optimization capabilities for the MFBS problem. We also employ a Taguchi approach to fine-tune the metaheuristics’ parameters. We widely examine and compare the metaheuristics’ performance across various-sized samples (small, medium, and large), considering solution quality, computational time, and the result stability of each algorithm. We also compare the metaheuristics’ solutions with the optimal solutions acquired by GAMS software in small and medium-scale samples. Our findings show that the GWO-SA outperforms the other metaheuristics. Applying our model to a real bus corridor in Santiago, Chile, we find that precise dispatching plans generated by more sophisticated/advanced algorithms (GA-SA and GWO-SA) lead to larger cost savings and improved performance compared to simpler algorithms (GA and GWO). Interestingly, utilizing more advanced algorithms makes a difference in terms of fleet planning in crowded scenarios, whereas for low and medium-demand cases, simpler dispatching algorithms could be used without a drop in accuracy.

Repairs and Breaks Prediction for Deep Neural Networks

With the increasing prevalence of software incorporating deep neural networks (DNNs), quality assurance for these software systems has become a crucial concern. To this end, various methods have been proposed to repair the misbehavior of DNNs by modifying their weights. However, these repair methods may not meet the developer's needs for a given dataset and model. In this study, we build prediction models for repair outcomes (i.e., repairs and breaks) to help determine whether the repair method is likely to work. By using our prediction models, developers and operators of DNNs can decide whether or not to apply a repair method, and if so, which method to use. Our prediction models utilize four metrics as explanatory metrics that represent the confidence or ambiguity in the DNN predictions. We experimented with four repair methods and 10 datasets. The experimental results demonstrate that our prediction models successfully select a repair method that meets developers’ needs in 16 out of 24 cases, resulting in an average time saving of 16.29% compared to the naive method. Based on these results, our prediction models can reduce costs for developers and operators when deciding whether to employ repair methods for real-world applications of DNNs.

Surgical Tray Optimization in the Setting of Cleft Lip and Palate Reconstruction: Implications for Operative Cost and Efficiency.

To assess surgical instrument usage in cleft lip (CL) and cleft palate (CP) surgery and create an optimized surgical tray with an associated cost-savings analysis. Prospective, observational study. Single institution, 6-month prospective review. A total of 10 primary CL surgeries and 10 primary CP surgeries were included in this study. Complete lists of surgical instruments utilized in CL and CP surgeries were collected. The average instrument UFs were 26.0% for CL and 22.6% for CP. The estimated costs were $33.15 to $290.29 for the original CL surgical tray and $10.20 to $63.80 for the optimized tray. For CP, the original tray's cost was estimated at $38.25 to $319.00, and the optimized tray at $9.18 to $57.42. This demonstrates a cost reduction of $22.95 to $226.49 for CL and $29.07 to 261.58 for CP. The idealized surgical instrument tray could contribute to reducing healthcare expenditures and promoting operating room efficiency, patient safety, and environmentally friendlier operating theaters.

Outcome of Transanal suture haemorrhoidopexy and Stapled haemorrhoidopexy -A prospective observational study

Background: Transanal suture haemorrhoidopexy is the preferred treatment due to its low cost, less post operative complication and decreased chance of recurrence in grade II and grade III Hemorrhoids. Objective: To compare the post-operative outcome of transanal suture haemorrhoidopexy and stapled haemorrhoidopexy in patients with grade II and III haemorrhoids. Methods: This study was conducted in the Department of Colorectal Surgery, Shaheed Suhrawardy Medical College hospital over a period of one-year. Sixty-two patients with haemorrhoids were enrolled in this study according to selection criteria. Data were collected, compiled and tabulated according to key variables. Qualitative data were expressed as frequency with percentage and quantitative data as mean with standard deviation. Quantitative data were analyzed by student’s t-test and qualitative data by Chi-square test. Data were processed and analyzed by using software SPSS 22.0. For all analyses p-value &lt;0.05 was considered statistically significant. Result: Mean age of the patients was 49.38 ± 7.17 years and 52.45 ± 6.17 years in Stapled hemorrhoidopexy and Trans anal suture hemorrhoidopexy group respectively (p&gt;0.05). Males were predominant in both the two groups. In stapled hemorrhoidopexy group, grade of hemorrhoids was II (51.6%) and III (48.4%) whereas in Transanal suture hemorrhoidopexy group, grade of hemorrhoids was II (38.7%) and III (61.3%) (p&gt;0.05). Operative time was lower in Stapled hemorrhoidopexy (26.93 ± 1.59 min) than Transanal suture hemorrhoidopexy (27.74 ± 1.63 min). Per operative bleeding was found more in stapled group. Most of the patients stayed in the hospital only one day in both the two groups. Only four patients in Stapled hemorrhoidopexy group and one patient in Transanal suture hemorrhoidopexy group stayed more than one day. Post-operative pain according to VAS was lower in Stapled hemorrhoidopexy group (1.90 ± 0.54) than Transanal suture hemorrhoidopexy group (2.09 ± 0.30) after 24 hours of the surgery. But there was no significant difference in pain after 7 days of surgery between the two groups. Post-operative complications were more in stapled hemorrhoidopexy than Trans anal suture hemorrhoidopexy, but not statistically significant. Recurrence (bleeding &amp; prolapse) found more in stapled group than suture hemorrhoidopexy group. Treatment cost was significantly lower in trans anal suture hemorrhoidopexy. Conclusion: Based on this study, transanal suture hemorrhoidopexy showed less intra and post-operative hemorrhage, shorter duration of hospital stay, lower post-operative complications, and lower recurrence rate when compared to stapled hemorrhoidopexy. However, these differences were not statistically significant. The only statistically significant difference was in the operative cost, which was in favor of transanal suture hemorrhoidopexy. J Shaheed Suhrawardy Med Coll 2023; 15(1): 45-49

Workflow improvement and financial gain after integration of high-throughput sample processing system with flow cytometer in a high-volume pathology laboratory: Results from a prospective comparative study using Lean principles

BackgroundHighly efficient clinical laboratories are essential for monitoring many human illnesses. Ampath Laboratory Services, the largest pathology lab in South Africa, analyzes large numbers of peripheral blood samples for CD4 levels yearly. ObjectiveTo assess productivity and quality of a newer integrated automated solution, the BD FACSDuet™ Sample Preparation System/BD FACSLyric™ Flow Cytometer using conventional assessment methods and Lean concepts. Materials and methodsThis prospective study compared the performance of the BD FACS™ Sample Preparation Assistant [SPA] III and BD FACSCanto™ II Flow Cytometer with the newly introduced integrated system (BD FACSDuet™/BD FACSLyric™). They were validated for accuracy, precision, and external quality assessment. Process mapping and Lean assessment helped identify steps leading to waste. An economic model was developed to characterize workflow and economic impact associated with total daily hands-on time, processing time, and reworks. ResultsStrong linear correlation was present between both systems. Precision and accuracy studies revealed that all coefficient of variation (CV)% values were below 20% of allowable limits. External proficiency assessments were within limits. The fully automated workflow of BD FACSDuet™/BD FACSLyric™ permitted better consistency with significantly shorter processing time and batch processing and reduced operator interventions. Lean assessment identified defects with motion, over-processing, waiting, and non-utilized talent. Significant reductions in hands-on and total daily processing time that could increase daily specimen testing efficiency and fewer reworks were associated with the BD FACSDuet™/BD FACSLyric™. Lean improvements translated to significant economic savings associated with operator costs and unnecessary reagent consumption. ConclusionBD FACSDuet™/BD FACSLyric™ is an accurate, reliable, and cost-effective fully automated system for high-volume flow cytometry labs that perform T-cell enumeration using a single-platform and single-tube approach.

Robotic Versus Laparoscopic Gastrectomy for Gastric Cancer: The Largest Systematic Reviews of 68,755 Patients and Meta-analysis.

This meta-analysis aimed to compare the efficacy of robotic gastrectomy (RG) and laparoscopic gastrectomy (LG) in treating gastric cancer (GC). A comprehensive literature search across PubMed, MEDLINE, and Web of Science identified 86 eligible studies, including 68,755 patients (20,894 in the RG group and 47,861 in the LG group). The analysis revealed that RG was associated with superior outcomes in several areas: more lymph nodes were harvested, intraoperative blood loss was reduced, postoperative hospital stays were shorter, and the time to first flatus and oral intake was shortened (all p<0.001). Additionally, RG resulted in lower incidences of conversion to open surgery (OR=0.62, p=0.004), reoperation (OR=0.68, p=0.010), overall postoperative complications (OR=0.82, p<0.001), severe complications (OR=0.65, p<0.001), and pancreatic complications (OR=0.60, p=0.004). However, RG had longer operative times and higher costs (both p<0.001). No significant differences were found between RG and LG in terms of resection margin distance, mortality, anastomotic leakage, or recurrence rates. RG is a safe and effective surgical option for patients of GC, but further improvements in operative duration and costs are needed.

Study on the effect of mitigation strategies for rail corrugation in metro lines

Rail corrugation appears as a periodic irregularity on the rail running surface that causes severe dynamic loads at the wheel-rail interface. These dynamic forces may generate ground-borne vibrations that propagate from the line to the surrounding buildings causing discomfort to residents. Rail grinding is the most used countermeasure for the mitigation of corrugation. However, this maintenance operation determines high operative costs if frequently performed and must be carefully scheduled. To this end, it is important to assess the effectiveness of other mitigation solutions that may prevent or slow down its growth. The main objective of this study is to investigate the formation of rail corrugation on a sharp curve of the Cityringen underground line in Copenhagen. A wheel-rail interaction model is developed in the frequency domain to identify the root causes of the problem on the specific curve and predict the corrugation wavelength. Once the accuracy of the model is tested against experimental observations on the reference curve, it is used to explore the effectiveness of different mitigation actions, such as the use of friction modifiers, the variation of the speed, track design and track gauge. The results indicate that friction modifiers and speed variation are the most effective measures.

Preoperative Care Intensity and Cost for Renal Colic: Implications for Surgical Value-Based Reforms.

The aim of this study was to identify preoperative patient/facility factors associated with postoperative and total episode-related costs using renal colic as a model surgical condition to improve value-based payment models. Using state Healthcare Cost and Utilization Project data, we performed a retrospective cohort study examining perioperative costs for individuals presenting to an emergency department for renal colic and who ultimately underwent definitive surgical management. We estimated multivariable ordered and binary logistic regressions to examine the association between preoperative and operative cost quartiles on the probability of specific postoperative cost quartiles after accounting for hospital and individual factors. We also performed logistic regressions to identify patients who deviated from predicted perioperative cost pathways. Among 2736 individuals included in our analysis, episode-related costs ranged from $4536 (bottom quartile) to $26,662 (top quartile). Individuals in the highest preoperative cost quartile experienced an 11.7% higher probability of remaining in the highest postoperative cost quartile relative to those in the lowest preoperative cost quartile (95% CI, 0.0709-0.163; P < .001). Delays in surgery (95% CI, 0.0869-0.163; P < .001) and Medicaid vs private insurance (95% CI, 0.01-0.0728; P < .01) were associated with a 12.5% and 4.1% higher probability of being in the top quartile of preoperative costs, respectively. Treating facility experience with value-based payment models did not influence perioperative costs. Using renal colic as a model surgical condition, our novel findings suggest that preoperative costs are associated with both postoperative and total episode-related costs and should be accounted for when designing future value-based payment models.

Sterile Draping of Operative Microscopes in Breast Free Flaps and Surgical Site Infections.

Operative microscopes are traditionally draped in single-use plastic to prevent infection theoretically. The necessity of this routine in breast free flap surgery is unclear. Alternatively, sterile wrapping of microscope handles would reduce operating room waste and provide a more cost-effective and environmentally sustainable approach to sterility. This study aimed to determine whether the draping technique used during abdominally based free flaps (Ab-FF) influenced the rate of surgical site infections. We conducted a retrospective review of Ab-FF performed consecutively between March 2017 and August 2022. Patient demographics, comorbidities, perioperative data, and postoperative complications were collected. The primary outcomes included postoperative surgical site infections and environmental impact. Of the 281 identified breasts reconstructed with Ab-FF, operating microscopes were sterilely covered with microscope drapes (n = 215) or handle covers (n = 66) composed of polyethylene-based plastic. Overall, postoperative infections occurred in 9.3% of cases (n = 26) in either the recipient breast (n = 11, 3.9%) or abdominal donor site (n = 15, 5.3%), primarily due to S. aureus and Streptococcus species . The handle (n = 6, 9.1%) and drape (n = 20, 9.3%) cohorts had similar infection rates with no sequelae of operative complications. In multivariate analysis, radiation was the only independent predictor of postoperative infection, while bilateral reconstructions were independently protective. Replacing a microscope drape with a handle reduces carbon emissions by 1276 grams of CO 2 and direct costs by $7.84 per item. The principles of "Lean and Green" surgery prioritize reducing operating room generated waste to achieve financial and environmental sustainability. This cohort study of 281 breast free flaps demonstrates that switching from whole microscope draping to handle wrapping was not associated with an increased rate or odds of infection. Adopting a microscope handle wrapping protocol decreased the carbon footprint and operative costs. The results of this study offer evidence to support adoption and further exploration of pragmatic, cost-effective, and sustainable approaches to microsurgical breast reconstruction.