scholarly journals Computational Evaluation of Surgical Design for Multisegmental Complex Congenital Tracheal Stenosis

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Limin Zhu ◽  
Xiaolei Gong ◽  
Jinlong Liu ◽  
Youjin Li ◽  
Yumin Zhong ◽  
...  
Keyword(s):  
Tracheal Stenosis ◽  
Computer Aided Design ◽  
Surgical Correction ◽  
Patient Specific ◽  
Congenital Tracheal Stenosis ◽  
Computational Evaluation ◽  
Life Threatening ◽  
Computational Fluid Dynamics Cfd ◽  
Aerodynamic Parameters ◽  
Aided Design

Multisegmental complex congenital tracheal stenosis (CTS) is an uncommon but potentially life-threatening malformation of the airway. Staged surgery is indicated for the complex pathophysiology of the abnormal trachea. Surgical intervention to fix the stenotic segments may result in different postoperative outcomes. However, only few studies reported the design of surgical correction for multisegmental CTS. We used computer-aided design (CAD) to simulate surgical correction under different schemes to develop a patient-specific tracheal model with two segmental stenoses. Computational fluid dynamics (CFD) was used to compare the outcomes of different designs. Aerodynamic parameters of the trachea were evaluated. An obvious interaction was found between the two segments of stenosis in different surgical designs. The surgical corrective order of stenotic segments greatly affected the aerodynamic parameters and turbulence flows downstream of tracheal stenosis and upstream of the bronchus. Patient-specific studies using CAD and CFD minimize the risk of staged surgical correction and facilitate quantitative evaluation of surgical design for multiple segments of complex CTS.

An Integrated Ship Re-Design/Modification Strategy

2019 ◽  
Vol 161 (A1) ◽  
Keyword(s):  
Computer Aided Design ◽  
Modular Design ◽  
Ship Hull ◽  
Cfd Model ◽  
Hull Form ◽  
Design Modification ◽  
Technical Parameters ◽  
Computational Fluid Dynamics Cfd ◽  
Bulbous Bow ◽  
Aided Design

Herein, we present an integrated ship re-design/modification strategy that integrates the ‘Computer-Aided Design (CAD)’ and ‘Computational Fluid Dynamics (CFD)’ to modify the ship hull form for better performance in resistance. We assume a modular design and the ship hull form modification focuses on the forward module (e.g. bulbous bow) and aft module (e.g. stern bulb) only. The ship hull form CAD model is implemented with NAPA*TM and CFD model is implemented with Shipflow**TM. The basic ship hull form parameters are not changed and the modifications in some of the technical parameters because of re-designed bulbous bow and stern bulb are kept at very minimum. The bulbous bow is re-designed by extending an earlier method (Sharma and Sha (2005b)) and stern bulb parameters for re-design are computed from the experience gained from literature survey. The re-designed hull form is modeled in CAD and is integrated and analyzed with Shipflow**TM. The CAD and CFD integrated model is validated and verified with the ITTC approved recommendations and guidelines. The proposed numerical methodology is implemented on the ship hull form modification of a benchmark ship, i.e. KRISO container ship (KCS). The presented results show that the modified ship hull form of KCS - with only bow and stern modifications - using the present strategy, results into resistance and propulsive improvement.

Novel Active Inflow Control Technology for Optimized Flow and Reduced Intervention

2021 ◽  
pp. 1-12
Author(s):  
Ashutosh Dikshit ◽  
Vivek Agnihotri ◽  
Mike Plooy ◽  
Amrendra Kumar ◽  
Seymur Gurbanov ◽  
...  
Keyword(s):  
Flow Control ◽  
Computer Aided Design ◽  
Process Development ◽  
Horizontal Wells ◽  
Field Trials ◽  
Control Device ◽  
Computational Fluid Dynamics Cfd ◽  
Inflow Control Device ◽  
Aided Design ◽  
Subsequent Intervention

Summary Integrating a flow control sliding sleeve into a sand screen can provide multiple advantages to the user in controlling the production inflow, but it comes with an increased completion cost as well as an increase in the number of interventions required when it is time to operate those valves. Especially in long horizontal wells, this can become time-consuming and inefficient. A few technologies exist to address this issue, but they either are too complex or require specialized rigging equipment at the wellsite, which is not desirable. As described herein, a unique, fit-for-application modular sliding sleeve sand screen assembly with dissolvable plugs was developed that eliminates the need for washpipe during run-in-hole (RIH) and allows flow control from several screens by means of a single sliding sleeve door (SSD), thereby also optimizing the subsequent intervention operations by reducing the number of SSDs in the well. The design and field installation of these modular screens is presented in this paper. The new modular sand screen consisted of an upper joint, modular middle joint, modular middle joint with an inflow control device (ICD) integrated into an SSD (with optional dissolvable plugs), a lower joint, and novel field-installable flow couplings between them. The design allows for any number of non-ICD/SSD screen joints to be connected to any number of ICD/SSD joints in any order. A computer-aided design was followed to achieve all the operational and mechanical requirements. Computational fluid dynamics (CFD) was used to optimize the flow performance characteristics. Prototypes were manufactured and tested before conducting successful field trials. The design process, development, and field installation results are presented herein.

scholarly journals Accuracy Assessment of Molded, Patient-Specific Polymethylmethacrylate Craniofacial Implants Compared to Their 3D Printed Originals

2020 ◽  
Vol 9 (3) ◽  
pp. 832 ◽  
Author(s):  
Dave Chamo ◽  
Bilal Msallem ◽  
Neha Sharma ◽  
Soheila Aghlmandi ◽  
Christoph Kunz ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Accuracy Assessment ◽  
Three Dimensional ◽  
Production Costs ◽  
Patient Specific ◽  
Patient Specific Implants ◽  
3D Printed ◽  
Cost Efficient ◽  
Craniofacial Implants ◽  
Aided Design

The use of patient-specific implants (PSIs) in craniofacial surgery is often limited due to a lack of expertise and/or production costs. Therefore, a simple and cost-efficient template-based fabrication workflow has been developed to overcome these disadvantages. The aim of this study is to assess the accuracy of PSIs made from their original templates. For a representative cranial defect (CRD) and a temporo-orbital defect (TOD), ten PSIs were made from polymethylmethacrylate (PMMA) using computer-aided design (CAD) and three-dimensional (3D) printing technology. These customized implants were measured and compared with their original 3D printed templates. The implants for the CRD revealed a root mean square (RMS) value ranging from 1.128 to 0.469 mm with a median RMS (Q1 to Q3) of 0.574 (0.528 to 0.701) mm. Those for the TOD revealed an RMS value ranging from 1.079 to 0.630 mm with a median RMS (Q1 to Q3) of 0.843 (0.635 to 0.943) mm. This study demonstrates that a highly precise duplication of PSIs can be achieved using this template-molding workflow. Thus, virtually planned implants can be accurately transferred into haptic PSIs. This workflow appears to offer a sophisticated solution for craniofacial reconstruction and continues to prove itself in daily clinical practice.

scholarly journals Patient-Specific Coronary Artery 3D Printing Based on Intravascular Optical Coherence Tomography and Coronary Angiography

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Chenxi Huang ◽  
Yisha Lan ◽  
Sirui Chen ◽  
Qing Liu ◽  
Xin Luo ◽  
...  
Keyword(s):  
Coronary Artery ◽  
3D Printing ◽  
Coronary Angiography ◽  
Coronary Arteries ◽  
Computer Aided Design ◽  
Patient Specific ◽  
3D Printing Technology ◽  
Vessel Lumen ◽  
Computer Aided ◽  
Aided Design

Despite the new ideas were inspired in medical treatment by the rapid advancement of three-dimensional (3D) printing technology, there is still rare research work reported on 3D printing of coronary arteries being documented in the literature. In this work, the application value of 3D printing technology in the treatment of cardiovascular diseases has been explored via comparison study between the 3D printed vascular solid model and the computer aided design (CAD) model. In this paper, a new framework is proposed to achieve a 3D printing vascular model with high simulation. The patient-specific 3D reconstruction of the coronary arteries is performed by the detailed morphological information abstracted from the contour of the vessel lumen. In the process of reconstruction which has 5 steps, the morphological details of the contour view of the vessel lumen are merged along with the curvature and length information provided by the coronary angiography. After comparing with the diameter of the narrow section and the diameter of the normal section in CAD models and 3D printing model, it can be concluded that there is a high correlation between the diameter of vascular stenosis measured in 3D printing models and computer aided design models. The 3D printing model has high-modeling ability and high precision, which can represent the original coronary artery appearance accurately. It can be adapted for prevascularization planning to support doctors in determining the surgical procedures.

scholarly journals Design and Analyses of a Transdermal Drug Delivery Device (TD3) †

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5090 ◽  
Author(s):  
Jennifer García ◽  
Ismael Ríos ◽  
Faruk Fonthal Rico
Keyword(s):  
Drug Delivery ◽  
Transdermal Drug Delivery ◽  
Computer Aided Design ◽  
Micro Electro Mechanical System ◽  
Discharge Process ◽  
Microneedle Array ◽  
Delivery Device ◽  
Drug Delivery Device ◽  
Computational Fluid Dynamics Cfd ◽  
Aided Design

In this paper, we introduce a novel type of transdermal drug delivery device (TD3) with a micro-electro-mechanical system (MEMS) design using computer-aided design (CAD) techniques as well as computational fluid dynamics (CFD) simulations regarding the fluid interaction inside the device during the actuation process. For the actuation principles of the chamber and microvalve, both thermopneumatic and piezoelectric principles are employed respectively, originating that the design perfectly integrates those principles through two different components, such as a micropump with integrated microvalves and a microneedle array. The TD3 has shown to be capable of delivering a volumetric flow of 2.92 × 10−5 cm3/s with a 6.6 Hz membrane stroke frequency. The device only needs 116 Pa to complete the suction process and 2560 Pa to complete the discharge process. A 38-microneedle array with 450 µm in length fulfills the function of permeating skin, allowing that the fluid reaches the desired destination and avoiding any possible pain during the insertion.

Optimal Sensor Design Using Patient-Specific Images

2010 ◽  
Vol 4 (2) ◽  
Author(s):  
Sukhi Basati ◽  
Timothy J. Harris ◽  
Andreas A. Linninger
Keyword(s):  
Computer Aided Design ◽  
Rational Design ◽  
Treatment Options ◽  
Patient Specific ◽  
Data Sets ◽  
Disease States ◽  
Magnetic Resonance Data ◽  
Computer Aided ◽  
Aided Design ◽  
Pathological Disease

In diseases such as hydrocephalus, the cerebral ventricles enlarge. The treatment options for these patients are presently based on pressure, which has limited capabilities. We present the design of a volume sensor as an alternative monitoring option. Through the use of computer aided design and simulation, we optimized a sensor in silico with fewer resources. Specifically, we designed a sensor for animal experimentation with a scalable procedure for human sensors. In this paper, we present a rational design approach for a sensor that integrates advances in medical imaging. Magnetic resonance data sets of both normal and diseased subjects were used as a virtual laboratory. Finite element simulations were performed under pathological disease states of the brain as a contribution toward an accelerated device design. An optimized sensor was then fabricated for these subjects based on the outcome of the simulations. In this paper, we explain how a computer aided subject-specific design was used to help fabricate and test our sensor.

Management of Severe Congenital Tracheal Stenosis

1994 ◽  
Vol 103 (5) ◽  
pp. 351-356 ◽  
Author(s):  
Michael E. Dunham ◽  
Lauren D. Holinger ◽  
Carl L. Backer ◽  
Constantine Mavroudis
Keyword(s):  
Cardiopulmonary Bypass ◽  
Tracheal Stenosis ◽  
Preoperative Diagnosis ◽  
Surgical Repair ◽  
Pericardial Patch ◽  
Congenital Tracheal Stenosis ◽  
Life Threatening ◽  
The Mean

We have managed 23 infants and children with severe tracheal stenosis due to congenital complete tracheal rings producing a long-segment stenosis of the trachea. Nineteen (83%) have survived this life-threatening cause of airway obstruction, 7 of whom also had pulmonary artery slings. Pericardial patch tracheoplasty facilitated by partial cardiopulmonary bypass is currently our preferred technique for surgical repair. Eighteen patients (78%) underwent operative intervention, 3 of whom (17%) have died since surgery. The mean follow-up is 4.5 years. Bronchoscopy is essential for preoperative diagnosis and accurate intraoperative incision of the trachea, and is critical for long-term postoperative airway management. The more distal lesions are associated with increased complications and a higher mortality rate.

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