scholarly journals A Comprehensive 3D-Molded Bone Flap Protocol for Patient-Specific Cranioplasty

2021 ◽  
Author(s):  
Raphael Bertani ◽  
Caio Moreno Perret Novo ◽  
Pedro Henrique Freitas ◽  
Amanda Amorin Nunes ◽  
Thiago Nunes Palhares ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Low Cost ◽  
Selective Laser Sintering ◽  
Operating Time ◽  
Ct Scanning ◽  
Patient Specific ◽  
Manufacturing Cost ◽  
Post Processing ◽  
Cross Sectional ◽  
Cranial Defect

Abstract We present a detailed step-by-step approach for the low-cost production and surgical implantation of cranial prostheses, aimed at restoring aesthetics, cerebral protection, and facilitating neurological rehabilitation. This protocol uses combined scan computed tomography (CT) cross-sectional images, in DICOM format, along with a 3D printing (additive manufacturing) setup. The in-house developed software InVesalius®️ is an open-source tool for medical imaging manipulation. The protocol describes image acquisition (CT scanning) procedures, and image post-processing procedures such as image segmentation, surface/volume rendering, mesh generation of a 3D digital model of the cranial defect and the desired prostheses, and their preparation for use in 3D printers. Furthermore, the protocol describes a detailed powder bed fusion additive manufacturing process, known as Selective Laser Sintering (SLS), using Polyamide (PA12) as feedstock to produce a 3-piece customized printed set per patient. Each set consists of a “cranial defect printout” and a “testing prosthesis” to assemble parts for precision testing, and a cranial “prostheses mold” in 2 parts to allow for the intraoperative modeling of the final implant cast using the medical grade Poly(methyl methacrylate) (PMMA) in a time span of a few min. The entire 3D processing time, including modelling, design, production, post-processing and qualification, takes approximately 42 h. Modeling the PMMA flap with a critical thickness of 4 mm by means of Finite Element Method (FEM) assures mechanical and impact properties to be slightly weaker than the bone tissue around it, a safety design to prevent fracturing the skull after a possible subsequent episode of head injury. On a parallel track, the Protocol seeks to provide guidance in the context of equipment, manufacturing cost and troubleshooting. Customized 3D PMMA prostheses offers a reduced operating time, good biocompatibility, and great functional and aesthetic outcomes. Additionally, it offers greater than 15-fold cost advantage over the usage of other materials, including metallic parts produced by additive manufacturing.

scholarly journals A Systematic Review on 3D-Printed Imaging and Dosimetry Phantoms in Radiation Therapy

2019 ◽  
Vol 18 ◽  
pp. 153303381987020 ◽  
Author(s):  
Rance Tino ◽  
Adam Yeo ◽  
Martin Leary ◽  
Milan Brandt ◽  
Tomas Kron
Keyword(s):  
Systematic Review ◽  
Quality Assurance ◽  
Additive Manufacturing ◽  
Image Quality Assessment ◽  
Low Cost ◽  
Acrylonitrile Butadiene Styrene ◽  
Limiting Factors ◽  
Patient Specific ◽  
Wide Range ◽  
Assurance Process

Introduction: Additive manufacturing or 3-dimensional printing has become a widespread technology with many applications in medicine. We have conducted a systematic review of its application in radiation oncology with a particular emphasis on the creation of phantoms for image quality assessment and radiation dosimetry. Traditionally used phantoms for quality assurance in radiotherapy are often constraint by simplified geometry and homogenous nature to perform imaging analysis or pretreatment dosimetric verification. Such phantoms are limited due to their ability in only representing the average human body, not only in proportion and radiation properties but also do not accommodate pathological features. These limiting factors restrict the patient-specific quality assurance process to verify image-guided positioning accuracy and/or dose accuracy in “water-like” condition. Methods and Results: English speaking manuscripts published since 2008 were searched in 5 databases (Google Scholar, Scopus, PubMed, IEEE Xplore, and Web of Science). A significant increase in publications over the 10 years was observed with imaging and dosimetry phantoms about the same total number (52 vs 50). Key features of additive manufacturing are the customization with creation of realistic pathology as well as the ability to vary density and as such contrast. Commonly used printing materials, such as polylactic acid, acrylonitrile butadiene styrene, high-impact polystyrene and many more, are utilized to achieve a wide range of achievable X-ray attenuation values from −1000 HU to 500 HU and higher. Not surprisingly, multimaterial printing using the polymer jetting technology is emerging as an important printing process with its ability to create heterogeneous phantoms for dosimetry in radiotherapy. Conclusion: Given the flexibility and increasing availability and low cost of additive manufacturing, it can be expected that its applications for radiation medicine will continue to increase.

Research on Surface Quality Enhancement of Wood-Plastic Composite Powder SLS Parts by Post Processing

2010 ◽  
Vol 113-116 ◽  
pp. 508-511 ◽  
Author(s):  
Wei Liang Zeng ◽  
Yan Ling Guo
Keyword(s):  
Surface Quality ◽  
Low Cost ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Wood Plastic Composite ◽  
Post Processing ◽  
Plastic Composite ◽  
Rp Process ◽  
Sintering Properties

According to its advantages, such as low-cost and green biological etc., Wood-Plastic Composite(WPC) is more suitable for make parts by Selective Laser Sintering(SLS) rapid prototyping (RP) process. With optimal design of components, the parts made by WPC have good mechanical properties as well as with good laser sintering properties. In order to further improve the surface quality of the parts, the post-processing–infiltrating with wax–is introduced. After post-processing, the void fraction is decreased from 51% to 7%, surface quality has been greatly improved, Ra belows 13µm on average, after polishing the surface is more smooth and Ra belows 5µm averagely，compared to those without post processing, surface roughness decrease 22% and 73% respectively.

scholarly journals Selective Laser Sintering (SLS) and Post-Processing of Prosopis Chilensis/Polyethersulfone Composite (PCPC)

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3034
Author(s):  
Aboubaker I. B. Idriss ◽  
Jian Li ◽  
Yangwei Wang ◽  
Yanling Guo ◽  
Elkhawad A. Elfaki ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Particle Distribution ◽  
Low Cost ◽  
Selective Laser Sintering ◽  
Single Layer ◽  
Dimensional Accuracy ◽  
Laser Sintering ◽  
Raw Material ◽  
Post Processing ◽  
Prosopis Chilensis

The range of selective laser sintering (SLS) materials is currently limited, and the available materials are often of high cost. Moreover, the mechanical strength of wood–plastic SLS parts is low, which restricts the application of a SLS technology. A new composite material has been proposed to address these issues, while simultaneously valorizing agricultural and forestry waste. This composite presents several advantages, including reduced pollution associated with waste disposal and reduced CO2 emission with the SLS process in addition to good mechanical strength. In this article, a novel and low-cost Prosopis chilensis/polyethersulfone composite (PCPC) was used as a primary material for SLS. The formability of PCPC with various raw material ratios was investigated via single-layer experiments, while the mechanical properties and dimensional accuracy of the parts produced using the various PCPC ratios were evaluated. Further, the microstructure and particle distribution in the PCPC pieces were examined using scanning electron microscopy. The result showed that the SLS part produced via 10/90 (wt/wt) PCPC exhibited the best mechanical strength and forming quality compared to other ratios and pure polyethersulfone (PES), where bending and tensile strengths of 10.78 and 4.94 MPa were measured. To improve the mechanical strength, post-processing infiltration was used and the PCPC-waxed parts were enhanced to 12.38 MPa and 5.73 MPa for bending and tensile strength.

scholarly journals An optimisation framework for designs for additive manufacturing combining design, manufacturing and post-processing

2021 ◽  
Vol 27 (11) ◽  
pp. 90-105
Author(s):  
Anton Wiberg ◽  
Johan Persson ◽  
Johan Ölvander
Keyword(s):  
Additive Manufacturing ◽  
Design Methodology ◽  
Manufacturing Cost ◽  
Design For Additive Manufacturing ◽  
Post Processing ◽  
Process Selection ◽  
Content Type ◽  
Post Process ◽  
Alternative Designs

Purpose The purpose of this paper is to present a Design for Additive Manufacturing (DfAM) methodology that connects several methods, from geometrical design to post-process selection, into a common optimisation framework. Design/methodology/approach A design methodology is formulated and tested in a case study. The outcome of the case study is analysed by comparing the obtained results with alternative designs achieved by using other design methods. The design process in the case study and the potential of the method to be used in different settings are also discussed. Finally, the work is concluded by stating the main contribution of the paper and highlighting where further research is needed. Findings The proposed method is implemented in a novel framework which is applied to a physical component in the case study. The component is a structural aircraft part that was designed to minimise weight while respecting several static and fatigue structural load cases. An addition goal is to minimise the manufacturing cost. Designs optimised for manufacturing by two different AM machines (EOS M400 and Arcam Q20+), with and without post-processing (centrifugal finishing) are considered. The designs achieved in this study show a significant reduction in both weight and cost compared to one AM manufactured geometry designed using more conventional methods and one design milled in aluminium. Originality/value The method in this paper allows for the holistic design and optimisation of components while considering manufacturability, cost and component functionality. Within the same framework, designs optimised for different setups of AM machines and post-processing can be automatically evaluated without any additional manual work.

scholarly journals Topology and FEA modeling and optimization of a patient-specific zygoma implant

2021 ◽  
Author(s):  
Abhijit Cholkar ◽  
David Kinahan ◽  
Dermot Brabazon
Keyword(s):  
Additive Manufacturing ◽  
Optimum Design ◽  
Optimization Technique ◽  
Operating Time ◽  
Topological Optimization ◽  
Implant Design ◽  
Patient Specific ◽  
Stainless Steel 316L ◽  
Element Analysis ◽  
Suitable Material

Additive manufacturing has proven to be a very beneficial production technology in the medical and healthcare industries. While existing for over four decades, recent work has seen great improvements in the quality of products; particularly in medical devices such as implants. Improved customization reduced operating time and increased cost-effectiveness associated with Metal AM for these products offers a new value proposition.  This paper investigates and evaluates modelling methods for the zygoma bone (human jawbone) and explores the most suitable material and optimum design for this critical biomedical implant. This paper proposes an innovative and efficient pre-process methodology that includes modelling, design validation, topological optimization, and numerical analysis. The method includes the generation of the model using reverse engineering of CT scan data and a topology optimization technique which makes the implant lightweight without causing excessive stress concentration. Static structural Finite Element Analysis was conducted to test three different biocompatible materials (Ti6Al4V, stainless steel 316L and CoCr alloys) which are commonly available for metal additive manufacturing. The stresses and conditions in the analysis were that of the human mastication process and all the implant design were tested with the three material types. The Taguchi method was used to determine the optimum design which was found to result in the highest mass reduction of 25% with Ti6Al4V as the implant material.

scholarly journals Application of 3D Printing Technology in Orthopedic Medical Implant -Spinal surgery as an example

2019 ◽  
Vol 5 (2) ◽  
pp. 3
Author(s):  
Rong Feng Zhang ◽  
Peng Yun Wang ◽  
Ming Yang ◽  
Xuebo Dong ◽  
Xue Liu ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Spinal Surgery ◽  
Surgical Planning ◽  
Operating Time ◽  
Manufacturing Technology ◽  
Patient Specific ◽  
Additive Manufacturing Technology ◽  
Patient Specific Implants ◽  
Surgical Guides ◽  
Communication Aid

Additive manufacturing has been used in complex spinal surgical planning since the 1990s and is now increasingly utilized to produce surgical guides, templates, and more recently customized implants. Surgeons report beneficial impacts using additively manufactured biomodels as pre-operative planning aids as it generally provides a better representation of the patient’s anatomy than on-screen viewing of computed tomography (CT) or magnetic resonance imaging (MRI). Furthermore, it has proven to be very beneficial in surgical training and in explaining complex deformity and surgical plans to patients/ parents. This paper reviews the historical perspective, current use, and future directions in using additive manufacturing in complex spinal surgery cases. This review reflects the authors’ opinion of where the field is moving in light of the current literature. Despite the reported benefits of additive manufacturing for surgical planning in recent years, it remains a high niche market. This review raises the question as to why the use of this technology has not progressed more rapidly despite the reported advantages – decreased operating time, decreased radiation exposure to patients intraoperatively, improved overall surgical outcomes, pre-operative implant selection, as well as being an excellent communication aid for all medical and surgical team members. Increasingly, the greatest benefits of additive manufacturing technology in spinal surgery are customdesigned drill guides, templates for pedicle screw placement, and customized patient-specific implants. In view of these applications, additive manufacturing technology could potentially revolutionize health care in the near future.

Additive Manufacturing-Based Adaptive Dynamic Parameter Characterization by Using Pressure-Fed Flexure Mechanisms

2019 ◽  
Author(s):  
ChaBum Lee ◽  
JaeMin Han ◽  
Gyu Ha Kim
Keyword(s):  
Additive Manufacturing ◽  
Dynamic Characteristics ◽  
Low Cost ◽  
Damping Ratio ◽  
Dynamic Parameter ◽  
Fluidic Channel ◽  
Cross Sectional ◽  
Channel Geometry ◽  
Dynamic Behaviors ◽  
Time Dynamic

Abstract This paper presents dynamic characteristics of pressure-fed flexure mechanisms with the additively manufactured internal fluidic channels. Additive manufacturing (AM) technology makes use of the mechanical design flexibility that can effectively control the material distribution in terms of stiffness and damping of the flexures. Five different fluidic channel geometry (circular, semicircular, inverse-semicircular, triangular, and inverse-triangular) with the same cross-sectional area was designed and fabricated inside of one-dimensional cantilever beam (10 × 30 × 100 mm3). Stiffness, damping ratio and natural frequency of each cantilever according to varying air pressure condition from 14.7 psi (atmospheric pressure) to 75 psi were characterized, and at the same time dynamic behaviors of each cantilever were identified by using dynamic signal analyzer. In addition, dynamic characteristics of water-filled flexure mechanism were compared to those of air-filled cases. As a result, the internal channel geometry and filled-in media in the channel have significant influences to determine dynamic characteristics of flexure mechanisms. Such pressure-fed mechanisms can be considered in the first stage of AM flexure design and fabrication processes to adaptively control dynamic behaviors in an easy, convenient and low-cost manner.

Patient-Specific Clavicle Reconstruction Using Digital Design and Additive Manufacturing

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Marie Cronskär ◽  
Lars-Erik Rännar ◽  
Mikael Bäckström ◽  
Kjell G Nilsson ◽  
Börje Samuelsson
Keyword(s):  
Additive Manufacturing ◽  
Complex Shape ◽  
Plate Osteosynthesis ◽  
Operating Time ◽  
Digital Design ◽  
Patient Specific ◽  
Functional Design ◽  
Actual Case ◽  
Clavicle Fractures ◽  
Ct Data

There is a trend toward operative treatment for certain types of clavicle fractures and these are usually treated with plate osteosynthesis. The subcutaneous location of the clavicle makes the plate fit important, but the clavicle has a complex shape, which varies greatly between individuals and hence standard plates often have a poor fit. Using computed tomography (CT) based design, the plate contour and screw positioning can be optimized to the actual case. A method for patient-specific plating using design based on CT-data, additive manufacturing (AM), and postprocessing was initially evaluated through three case studies, and the plate fit on the reduced fracture was tested during surgery (then replaced by commercial plates). In all three cases, the plates had an adequate fit on the reduced fracture. The time span from CT scan of the fracture to final implant was two days. An approach to achieve functional design and screw-hole positioning was initiated. These initial trials of patient-specific clavicle plating using AM indicate the potential for a smoother plate with optimized screw positioning. Further, the approach facilitates the surgeon's work and operating time can be saved.

scholarly journals Interfacial Bonding Mechanism and Mechanical Performance of Continuous Fiber Reinforced Composites in Additive Manufacturing

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Congze Fan ◽  
Zhongde Shan ◽  
Guisheng Zou ◽  
Li Zhan ◽  
Dongdong Yan
Keyword(s):  
Additive Manufacturing ◽  
Mechanical Performance ◽  
Theoretical Calculations ◽  
Ct Scanning ◽  
Interfacial Bonding ◽  
Continuous Fiber ◽  
Forming Process ◽  
Cross Sectional ◽  
Neck Size ◽  
Bonding Performance

AbstractThe additive manufacturing of continuous fiber composites has the advantage of a high-precision and efficient forming process, which can realize the lightweight and integrated manufacturing of complex structures. However, many void defects exist between layers in the printing process of additive manufacturing; consequently, the bonding performance between layers is poor. The bonding neck is considered a key parameter for representing the quality of interfacial bonding. In this study, the formation mechanism of the bonding neck was comprehensively analyzed. First, the influence of the nozzle and basement temperatures on the printing performance and bonding neck size was measured. Second, CT scanning was used to realize the quantitative characterization of bonding neck parameters, and the reason behind the deviation of actual measurements from theoretical calculations was analyzed. When the nozzle temperature increased from 180 to 220 °C, CT measurement showed that the bonding neck diameter increased from 0.29 to 0.34 mm, and the cross-sectional porosity reduced from 5.48% to 3.22%. Finally, the fracture mechanism was studied, and the influence of the interfacial bonding quality on the destruction process of the materials was determined. In conclusion, this study can assist in optimizing the process parameters, which improves the precision of the printing parts and performance between the layers.

Sign in / Sign up

Export Citation Format

Share Document