scholarly journals Outcome Validation of a Simulation Based Patient Specific TKA Planning Tool

10.29007/3mvp ◽  
2020 ◽  
Author(s):  
Joshua Twiggs ◽  
Justin Roe ◽  
Brett Fritsch ◽  
David Parker ◽  
Brad Miles
Keyword(s):  
Patient Specific ◽  
Predictive Algorithm ◽  
Significant Relationships ◽  
Simulation Based ◽  
Joint Dynamics ◽  
Operative Planning ◽  
The Impact ◽  
Future Patient ◽  
Selection Of ◽  
Knee Rig

Dynamic knee computer simulations are a promising surgical planning option in TKA, allowing the impact of plan alterations on joint dynamics to be analysed prior to surgery. Previously, the dynamic results of our simulation have been shown to correlate with outcome; here we show validation of its use in pre-operative planning.A database of TKA Patients undergoing surgery from 1-Jan-2014 operated on by 9 surgeons, who received a pre-operative and post-operative CT were assessed. A musculoskeletal computational model with similar boundary conditions to the Oxford Knee Rig was used to simulate post-TKA knee dynamics using Adams MSC software (Newport, CA). In addition, a set of pre-operative simulations were generated covering positional variations. The Dynamic Knee Score (DKS), a predictive algorithm machine learned from KOOS scored postoperative cases to predict outcome in preoperative planning was applied to all simulations.Patients were split into groups depending on whether the ‘post-operative achieved position’ was the ‘best’ of the preoperative modelled options in terms of simulated DKS score or not. These results were compared with 12 month postoperative KOOS scores. Cases where the best plan was followed had better outcome results. A relationship was shown with the KOOS Pain subscore, with the portion of patients below a KOOS Pain score of 70 dropping to 11% from 16% (p=0.030) when the best plan was followed.This study shows significant relationships between selection of patient specific kinematically optimal surgical plan and outcome. Such tools will play an important role in future patient specific decision making.

scholarly journals Numerical Parametric Study of Paravalvular Leak Following a Transcatheter Aortic Valve Deployment Into a Patient-Specific Aortic Root

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Wenbin Mao ◽  
Qian Wang ◽  
Susheel Kodali ◽  
Wei Sun
Keyword(s):  
Aortic Valve ◽  
Computational Model ◽  
Aortic Root ◽  
Paravalvular Leak ◽  
Patient Specific ◽  
Fe Method ◽  
Transcatheter Aortic Valve ◽  
Operative Planning ◽  
The Difference ◽  
The Impact

Paravalvular leak (PVL) is a relatively frequent complication after transcatheter aortic valve replacement (TAVR) with increased mortality. Currently, there is no effective method to pre-operatively predict and prevent PVL. In this study, we developed a computational model to predict the severity of PVL after TAVR. Nonlinear finite element (FE) method was used to simulate a self-expandable CoreValve deployment into a patient-specific aortic root, specified with human material properties of aortic tissues. Subsequently, computational fluid dynamics (CFD) simulations were performed using the post-TAVR geometries from the FE simulation, and a parametric investigation of the impact of the transcatheter aortic valve (TAV) skirt shape, TAV orientation, and deployment height on PVL was conducted. The predicted PVL was in good agreement with the echocardiography data. Due to the scallop shape of CoreValve skirt, the difference of PVL due to TAV orientation can be as large as 40%. Although the stent thickness is small compared to the aortic annulus size, we found that inappropriate modeling of it can lead to an underestimation of PVL up to 10 ml/beat. Moreover, the deployment height could significantly alter the extent and the distribution of regurgitant jets, which results in a change of leaking volume up to 70%. Further investigation in a large cohort of patients is warranted to verify the accuracy of our model. This study demonstrated that a rigorously developed patient-specific computational model can provide useful insights into underlying mechanisms causing PVL and potentially assist in pre-operative planning for TAVR to minimize PVL.

On the Applicability of Analytical Supply Chain Disruption Models for Selecting the Optimum Contingency Strategies for Electronic Supply Chain Disruption Management: A Comparison With Simulation

2014 ◽  
Author(s):  
Hannah Allison ◽  
Peter Sandborn ◽  
Bo Eriksson
Keyword(s):  
Supply Chain ◽  
Mitigation Strategy ◽  
Mitigation Strategies ◽  
Analytical Models ◽  
Supply Chain Disruption ◽  
Simulation Based ◽  
Disruption Mitigation ◽  
The Impact ◽  
Selection Of

Due to the nature of the manufacturing and support activities associated with long life cycle products, the parts that products required need to be dependably and consistently available. However, the parts that comprise long lifetime products are susceptible to a variety of supply chain disruptions. In order to minimize the impact of these unavoidable disruptions to production, manufacturers can implement proactive mitigation strategies. Two mitigation strategies in particular have been proven to decrease the penalty costs associated with disruptions: second sourcing and buffering. Second sourcing involves selecting two distinct suppliers from which to purchase parts over the life of the part’s use within a product or organization. Second sourcing reduces the probability of part unavailability (and its associated penalties), but at the expense of qualification and support costs for multiple suppliers. An alternative disruption mitigation strategy is buffering (also referred to as hoarding). Buffering involves stocking enough parts in inventory to satisfy the forecasted part demand (for both manufacturing and maintenance requirements) for a fixed future time period so as to offset the impact of disruptions. Careful selection of the mitigation strategy (second sourcing, buffering, or a combination of the two) is key, as it can dramatically impact a part’s total cost of ownership. This paper studies the effectiveness of traditional analytical models compared to a simulation-based approach for the selection of an optimal disruption mitigation strategy. A verification case study was performed to check the accuracy and applicability of the simulation-based model. The case study results show that the simulation model is capable of replicating results from operations research models, and overcomes significant scenario restrictions that limit the usefulness of analytical models as decision-making tools. Four assumptions, in particular, severely limit the realism of most analytical models but do not constrain the simulation-based model. These limiting assumptions are: 1) no fixed costs associated with part orders, 2) infinite-horizon, 3) perfectly reliable backup supplier, and 4) disruptions lasting full ordering periods (as opposed to fractional periods).

scholarly journals Intra-Operative and Anatomic Verification of a TKA Computational Model for Pre-Operative Surgical Planning

10.29007/hvqg ◽  
2019 ◽  
Author(s):  
Joshua Twiggs ◽  
Edgar Wakelin ◽  
Justin Roe ◽  
Brett Fritsch ◽  
Brad Miles
Keyword(s):  
Total Knee Arthroplasty ◽  
Contact Force ◽  
Knee Arthroplasty ◽  
Patient Specific ◽  
Koos Score ◽  
Significant Difference ◽  
Patient Reported ◽  
Joint Dynamics ◽  
Operative Planning ◽  
Total Knee

A promising measure of dynamic outcomes in Total Knee Arthroplasty (TKA) is the simulation of joint dynamics. These simulations are potentially useful for pre-operative planning, but are not yet validated for patient-specific variations in anatomy, which forms the aim of this paper. 284 patients from a database of total knee arthroplasty patients were analysed using a pre-operatively defined simulation predicting post-operative knee dynamics; each patient had previously undergone pre- and post-operative CT imaging and had been assessed using the Knee Injury and Osteoarthritis Outcome (KOOS) score at 6 months following surgery. A significant correlation was found between the simulated contact force and laxity in mid-flexion (r=-0.452, p<0.0001), and between the medio- lateral difference in contact force and difference in distal-vs-posterior femoral collateral ligament offset (r=-0.473, p<0.0001). A significant difference of 5 KOOS pain points (p=0.02) was found for patients with unusually low or high simulated contact force compared to normal. These results indicate the preoperative simulation is capable of distinguishing patient-specific kinematics prior to surgery, thereby demonstrating the utility of this simulation for making pre-surgical predictions of patient-specific kinematics and patient-reported outcomes.

Methods for Restricting Maximum Exposure Rate in Computerized Adaptative Testing

Methodology ◽  
2007 ◽  
Vol 3 (1) ◽  
pp. 14-23 ◽  
Author(s):  
Juan Ramon Barrada ◽  
Julio Olea ◽  
Vicente Ponsoda
Keyword(s):  
Measurement Accuracy ◽  
Computerized Adaptive Testing ◽  
Computation Time ◽  
Adaptive Testing ◽  
Exposure Rate ◽  
Control Parameters ◽  
The Impact ◽  
Two Alternatives ◽  
Selection Of ◽  
Maximum Exposure

Abstract. The Sympson-Hetter (1985) method provides a means of controlling maximum exposure rate of items in Computerized Adaptive Testing. Through a series of simulations, control parameters are set that mark the probability of administration of an item on being selected. This method presents two main problems: it requires a long computation time for calculating the parameters and the maximum exposure rate is slightly above the fixed limit. Van der Linden (2003) presented two alternatives which appear to solve both of the problems. The impact of these methods in the measurement accuracy has not been tested yet. We show how these methods over-restrict the exposure of some highly discriminating items and, thus, the accuracy is decreased. It also shown that, when the desired maximum exposure rate is near the minimum possible value, these methods offer an empirical maximum exposure rate clearly above the goal. A new method, based on the initial estimation of the probability of administration and the probability of selection of the items with the restricted method ( Revuelta & Ponsoda, 1998 ), is presented in this paper. It can be used with the Sympson-Hetter method and with the two van der Linden's methods. This option, when used with Sympson-Hetter, speeds the convergence of the control parameters without decreasing the accuracy.

Uncovering the Diversification of Tissue Engineering on the Emergent Areas of Stem Cells, Nanotechnology and Biomaterials

2020 ◽  
Vol 15 (3) ◽  
pp. 187-201 ◽  
Author(s):  
Sunil K. Dubey ◽  
Amit Alexander ◽  
Munnangi Sivaram ◽  
Mukta Agrawal ◽  
Gautam Singhvi ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Stem Cells ◽  
Immune System ◽  
Clinical Application ◽  
Cell Types ◽  
Patient Specific ◽  
Potential Strategy ◽  
Induced Pluripotent ◽  
Treat All ◽  
The Impact

Damaged or disabled tissue is life-threatening due to the lack of proper treatment. Many conventional transplantation methods like autograft, iso-graft and allograft are in existence for ages, but they are not sufficient to treat all types of tissue or organ damages. Stem cells, with their unique capabilities like self-renewal and differentiate into various cell types, can be a potential strategy for tissue regeneration. However, the challenges like reproducibility, uncontrolled propagation and differentiation, isolation of specific kinds of cell and tumorigenic nature made these stem cells away from clinical application. Today, various types of stem cells like embryonic, fetal or gestational tissue, mesenchymal and induced-pluripotent stem cells are under investigation for their clinical application. Tissue engineering helps in configuring the stem cells to develop into a desired viable tissue, to use them clinically as a substitute for the conventional method. The use of stem cell-derived Extracellular Vesicles (EVs) is being studied to replace the stem cells, which decreases the immunological complications associated with the direct administration of stem cells. Tissue engineering also investigates various biomaterials to use clinically, either to replace the bones or as a scaffold to support the growth of stemcells/ tissue. Depending upon the need, there are various biomaterials like bio-ceramics, natural and synthetic biodegradable polymers to support replacement or regeneration of tissue. Like the other fields of science, tissue engineering is also incorporating the nanotechnology to develop nano-scaffolds to provide and support the growth of stem cells with an environment mimicking the Extracellular matrix (ECM) of the desired tissue. Tissue engineering is also used in the modulation of the immune system by using patient-specific Mesenchymal Stem Cells (MSCs) and by modifying the physical features of scaffolds that may provoke the immune system. This review describes the use of various stem cells, biomaterials and the impact of nanotechnology in regenerative medicine.

Analysis of the Most Valued Organization to Work for in Spain, According to Nationality and Location

2019 ◽  
Vol 5 (2) ◽  
pp. 83-99
Author(s):  
Francisco Jesús Ferreiro Seoane ◽  
Manuel Octavio Del Campo Villares
Keyword(s):  
Work Environment ◽  
Talent Management ◽  
Point Of View ◽  
Added Value ◽  
Quantitative Character ◽  
Autonomous Communities ◽  
Professional Performance ◽  
Significant Relationships ◽  
Pearson Correlations ◽  
Selection Of

Background: The objective of this article is to analyse if there are significant relationships between the most valuable companies operating in Spain regarding professional performance, according to nationality and location within their Autonomous Communities or any superior aggrupation. To do that, a sample of 100 companies has been selected. Methods: The methodology followed is based on the selection of the 100 highestvalued companies from the point of view of Human Resources’ policy for the period 2013-2016 and through the measurement of six factors: Talent Management, Retribution, Work environment, CSR, Training and Employees’ perception, and classified by nationality and location. The study was based on 12 hypotheses, using the Unifactorial Variance’s Analysis, Pearson correlations and regressions. One limitation could be the fact that this study refers to a particular period, focusing on Spain and the variables mentioned, based on questionnaires. The added value of this work lies on the newness as it has a quantitative character, and on the fact that most of the hypotheses do not comply. Results and Conclusion: This allows to deny certain beliefs that affirm that European and American companies operating in Spain are more attractive than the Spanish or the Mediterranean ones.

Impact of removing ESBL designation from culture reports on the selection of antibiotics for the treatment of infections associated with ESBL-producing organisms

2020 ◽  
Vol 41 (5) ◽  
pp. 604-607 ◽  
Author(s):  
Mark D. Lesher ◽  
Cory M. Hale ◽  
Dona S. S. Wijetunge ◽  
Matt R. England ◽  
Debra S. Myers ◽  
...  
Keyword(s):  
Antimicrobial Stewardship ◽  
Antibiotic Prescribing ◽  
The Impact ◽  
Inhibitor Combination ◽  
Lactamase Inhibitor ◽  
Selection Of

AbstractWe characterized the impact of removal of the ESBL designation from microbiology reports on inpatient antibiotic prescribing. Definitive prescribing of carbapenems decreased from 48.4% to 16.1% (P = .01) and β-lactam–β-lactamase inhibitor combination increased from 19.4% to 61.3% (P = .002). Our findings confirm the importance of collaboration between microbiology and antimicrobial stewardship programs.

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