scholarly journals In Vivo Tibial Fit and Rotational Analysis of a Customized, Patient-Specific TKA versus Off-the-Shelf TKA

2018 ◽  
Vol 32 (06) ◽  
pp. 499-505 ◽  
Author(s):  
Lennart Schroeder ◽  
Gregory Martin
Keyword(s):  
Computer Aided Design ◽  
Rotational Alignment ◽  
Patient Specific ◽  
Tibial Tubercle ◽  
Rotational Axis ◽  
Rotational Analysis ◽  
Total Knee ◽  
Aided Design ◽  
Rotational Deviation

AbstractIn total knee arthroplasty (TKA), surgeons often face the decision of maximizing tibial component fit and achieving correct rotational alignment at the same time. Customized implants (CIMs) address this difficulty by aiming to replicate the anatomical joint structure, utilizing data from patient-specific knee geometry during the manufacturing. We intraoperatively compared component fit in four tibial zones of a CIM to that of three different off-the-shelf (OTS) TKA designs in 44 knees. Additionally, we assessed the rotational alignment of the tibia using computed tomography (CT)-based computer aided design model analysis. Overall the CIM device showed significantly better component fit than the OTS TKAs. While 18% of OTS designs presented an implant overhang of 3 mm or more, none of the CIM components did (p < 0.05). There was a larger percentage of CIMs seen with optimal fit (≤1 mm implant overhang to ≤1 mm tibial bone undercoverage) than in OTS TKAs. Also, OTS implants showed significantly more component underhang of ≥3 mm than the CIM design (37 vs. 18%). The rotational analysis revealed that 45% of the OTS tibial components showed a rotational deviation of more than 5 degrees and 4% of more than 10 degrees to a tibial rotational axis described by Cobb et al. No deviation was seen for the CIM, as the device is designed along this axis. Using the medial one-third of the tibial tubercle as the rotational landmark, 95% of the OTS trays demonstrated a rotational deviation of more than 5 degrees and 73% of more than 10 degrees compared with 73% of CIM tibial trays with more than 5 degrees and 27% with more than 10 degrees. Based on our findings, we believe that the CIM TKA provides both better rotational alignment and tibial fit without causing overhang of the tibial tray than the three examined OTS implants.

scholarly journals Prototype of Augmented Reality Technology for Orthodontic Bracket Positioning: An In Vivo Study

2021 ◽  
Vol 11 (5) ◽  
pp. 2315
Author(s):  
Yu-Cheng Lo ◽  
Guan-An Chen ◽  
Yin Chun Liu ◽  
Yuan-Hou Chen ◽  
Jui-Ting Hsu ◽  
...  
Keyword(s):  
Augmented Reality ◽  
Navigation System ◽  
Computer Aided Design ◽  
Control Group ◽  
Orthodontic Bracket ◽  
Bracket Position ◽  
Aided Design ◽  
Clinical Error ◽  
And Control

To improve the accuracy of bracket placement in vivo, a protocol and device were introduced, which consisted of operative procedures for accurate control, a computer-aided design, and an augmented reality–assisted bracket navigation system. The present study evaluated the accuracy of this protocol. Methods: Thirty-one incisor teeth were tested from four participators. The teeth were bonded by novice and expert orthodontists. Compared with the control group by Boone gauge and the experiment group by augmented reality-assisted bracket navigation system, our study used for brackets measurement. To evaluate the accuracy, deviations of positions for bracket placement were measured. Results: The augmented reality-assisted bracket navigation system and control group were used in the same 31 cases. The priority of bonding brackets between control group or experiment group was decided by tossing coins, and then the teeth were debonded and the other technique was used. The medium vertical (incisogingival) position deviation in the control and AR groups by the novice orthodontist was 0.90 ± 0.06 mm and 0.51 ± 0.24 mm, respectively (p < 0.05), and by the expert orthodontist was 0.40 ± 0.29 mm and 0.29 ± 0.08 mm, respectively (p < 0.05). No significant changes in the horizontal position deviation were noted regardless of the orthodontist experience or use of the augmented reality–assisted bracket navigation system. Conclusion: The augmented reality–assisted bracket navigation system increased the accuracy rate by the expert orthodontist in the incisogingival direction and helped the novice orthodontist guide the bracket position within an acceptable clinical error of approximately 0.5 mm.

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.

Geometric Measurement of Wear in Tibial Inserts Through an Autonomous Reconstruction of the Original Surface

2011 ◽  
Author(s):  
Christopher B. Knowlton ◽  
George Hanson ◽  
Diego Orozco ◽  
Michel P. Laurent ◽  
Markus A. Wimmer
Keyword(s):  
Computer Aided Design ◽  
Design Parameters ◽  
Limiting Factor ◽  
Total Knee Replacements ◽  
Knee Replacements ◽  
Cad Models ◽  
Total Knee ◽  
Aided Design ◽  
Geometric Measurement ◽  
Worn Surfaces

Wear of the polyethylene tibial components in total knee replacements remains a limiting factor of implant life. Studies have used coordinate measuring machines (CMM) to estimate volumetric wear in retrieved components. This technique requires knowledge of the original pre-worn surfaces. Pre-worn surfaces have been successfully approximated in literature by nominal computer-aided design (CAD) models or, more commonly, size-matched unused inserts [1,2]. However, models and drawings of implants are proprietary, and many design parameters can have large tolerances. Unworn components are costly, often unattainable for obsolete implants and subject to deviation between batches.

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 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.

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.

Automated Virtual Placement and Evaluation of Tibial Components for Knee Arthroplasty

2011 ◽  
Author(s):  
Yifei Dai ◽  
Mary S. S. Wentorf ◽  
Jeffrey E. Bischoff
Keyword(s):  
Knee Arthroplasty ◽  
Rotational Alignment ◽  
Implant Design ◽  
Rotational Axis ◽  
Rotational Malalignment ◽  
Tibial Tray ◽  
Key Factor ◽  
Total Knee ◽  
The Impact ◽  
Good Coverage

The ability of tibial tray component shapes to appropriately fit boney geometry is an important aspect of implant design in total knee arthroplasty. Overhang of components in the knee has been associated with soft tissue damage and joint pain [1,2]. Good coverage establishes stability through adequate cortical bone support of the tray component, and reduces the likelihood of loosening and subsidence [3–5], and therefore serves as a key factor in component fixation, especially in those that rely on biological growth into porous component backings such as Trabecular Metal™ Material. More importantly, rotational malalignment of the tibial tray can disrupt the natural kinematics and implant longevity [6]. Previous studies investigated coverage of multiple tibial trays on digitized bone resection contours [1,7]. However the methodology for rotational alignment during implantation was not identified. Although rotational alignment has been investigated in numerous studies, most of the studies were carried out by either investigating the impact of malalignment [6], or assessing different definitions of the tibia rotational axis [8]. No correlation between the size of the rotational alignment window and the amount of coverage has been shown.

Cholinesterase Reactivation in Vivo with a Novel Bis-Oxime Optimized by Computer-Aided Design

2003 ◽  
Vol 307 (1) ◽  
pp. 190-196 ◽  
Author(s):  
P. I. Hammond ◽  
C. Kern ◽  
F. Hong ◽  
T. M. Kollmeyer ◽  
Y.-P. Pang ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Computer Aided ◽  
Aided Design ◽  
Cholinesterase Reactivation
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