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1 – 10 of over 1000Arkadiusz Miaskowski, Andrzej Krawczyk and Yoshiyuki Ishihara
The purpose of this paper is to use numerical methods and modelling to estimate the effect of a passive, metallic (conducting) implant on eddy currents distribution in a human…
Abstract
Purpose
The purpose of this paper is to use numerical methods and modelling to estimate the effect of a passive, metallic (conducting) implant on eddy currents distribution in a human knee model. There exists a concern among wearers of such implants that they alter electromagnetic field (eddy currents) significantly and there is a need for standardization of that problem.
Design/methodology/approach
The numerical model of a human knee has been built on the base of Visual Human Project and electromagnetic field calculations were carried out using Meep FDTD engine. In total, two scenarios have been considered: the knee model with and without a metallic implant. The knee implant model has been prepared as the knee model with overestimated electrical parameters of bone tissues by titanium metal. Alternating eddy current distribution has then been evaluated for both models using FDTD low frequency algorithm.
Findings
The highest values of eddy currents occurred on the interface between skin and muscle tissues when the model without an implant is considered. However, when the bone tissues have been replaced with titanium metal, the highest values have occurred in the implant (about 100 times higher than the previous one). This means that an implant can be heated by external electromagnetic fields and that the location of the highest values of eddy currents can be shifted to the proximity of the implant. Moreover, one should realize that in this model the implant is like a knee bone with all anatomical details. It has emerged from this that the implant's shape and size are essential when evaluating its effect on eddy currents distribution.
Practical implications
The interaction of electromagnetic field with implants should be generally further investigated, at least for the presumable worst cases. Such investigation has already been done by some researches but they have been devoted to radio frequencies. The authors believe that the presented research will be helpful in the standardization process, when talking about low frequency electromagnetic field.
Originality/value
The presented methodology can be used in the development of computer aid diagnosis systems. Overestimation of electrical parameters of some parts of the model allows us to predict the distribution of electromagnetic field in the model under investigation very quickly. The results presented in the paper can be used during the standardization process.
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Vijay Kumar Meena, Gagandeep, Aneesh, Vidya Rattan, Gaurav Luthra and Parveen Kalra
The purpose of this paper is to design and development of a patient-specific implant for zygomatic area of a patient suffering from mucormycosis (fungal infection). The paper…
Abstract
Purpose
The purpose of this paper is to design and development of a patient-specific implant for zygomatic area of a patient suffering from mucormycosis (fungal infection). The paper describes how integration of computer-aided design (CAD) and 3D printing can be successfully used for developing custom implants for the sites for which readymade optimal solutions are not available.
Design/methodology/approach
The CT scan data of the patient were used for the generation of a 3D model. The healthy side of skull was mirrored and copied on the infected part, which served as a base for designing the implant. The prototype of the implant was printed using fused deposition modelling before finally printing in Ti6Al4V alloy using direct metal laser sintering process.
Findings
The custom designed implant fitted well to the patient’s skull during surgery. Proper facial aesthetics were maintained post-surgery.
Originality/value
The work describes the application of CAD-based image processing software and additive manufacturing in the development of a custom implant for the sites for which no readymade optimal solution is available.
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Vivek Kumar Tiwary, Arunkumar P., Anand S. Deshpande and Nikhil Rangaswamy
Due to intrinsic limitations, fused deposition modelling (FDM) products suffer from the bad surface finish and inaccurate dimensional accuracies restricting its usage in many…
Abstract
Purpose
Due to intrinsic limitations, fused deposition modelling (FDM) products suffer from the bad surface finish and inaccurate dimensional accuracies restricting its usage in many applications. Hence, there is a need for processing polymer patterns before, during and after their productions. This paper aims to highlight the importance of pre- and post-processing treatments on the FDM-based acrylonitrile butadiene styrene patterns improving its surface quality so, that it can be used in rapid investment casting process for making medical implants and other high precision components.
Design/methodology/approach
As a part of pre-processing treatment, the machine parameters affecting the surface quality were identified and optimised using design of experiments. The patterns developed after the first stage of optimisation were given different post-processing treatments, which included vapour smoothening, chemical treatment and sand paper polishing. The results were compared and the best ones were used for making patterns for making medical implants via rapid investment casting technique. The surface quality was checked while the dimensional changes happening during the stages of this hybrid technique were recorded using a three-dimensional optical scanner.
Findings
The surface roughness of the FDM based ABS patterns reduced from 21.63 to 14.40 µm with pre-processing treatments. Chemical treatment (post-processing treatment) turned to be the most suitable technique for reducing the surface roughness further down to 0.30 µm. Medical implants that used these pre- and post-processing treatments gave an average surface roughness of 0.68 µm. Cost and lead time comparisons showed that rapid investment casting technique can be a better method for low volume, customised and with specific requirements.
Originality/value
FDM parts/medical implants produced by rapid investment casting technique suffer from the inferior surface finish and inaccurate dimensional accuracies limiting its applications. A systematic approach to overcome this issue is presented in this research paper. This will directly help the end users and the manufacturers of medical implants, wherein, better surface finish and dimensionally accurate components are expected.
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Adrian Bartlomiej Mróz, Lukasz Lapaj, Tomasz Wisniewski, Konstanty Skalski and Volf Leshchynsky
Orthopaedic implants, such as intervertebral disc endoprostheses (IDEs) are difficult to manufacture by means of conventional methods because of their complex shape. However…
Abstract
Purpose
Orthopaedic implants, such as intervertebral disc endoprostheses (IDEs) are difficult to manufacture by means of conventional methods because of their complex shape. However, technologies developed in recent years, such as selective laser melting, could simplify this process. Although this method is attractive in both manufacturing and rapid prototyping of IDEs, little is known about their tribological performance. The functional aim of the work is to conduct a tribological evaluation of the ASTM F75 alloy after selective laser melting process and to investigate the viability of the technology in IDE design. The research aim was an explanation of the wear mechanism of bearing surfaces with respect to the reference material.
Design/methodology/approach
In this paper, the tribological test results of a lumbar IDE prototype fabricated by selective laser melting and forging is presented and compared. The endoprostheses were fabricated from commercially available ASTM F75 powder using a selective laser melting device. As a reference material, a forged ASTM F1537 LC alloy was used. Comparative wear and friction tests were carried out with the use of a unique spine simulator.
Findings
The obtained results confirm the viability of the selective laser technology in endoprosthesis design. Unfortunately, poorer tribological wear resistance of endoprostheses produced by means of selective laser melting (SLM) technology compared with that of the reference material calls into question the possibility of using these technologies in the manufacturing process of endoprosthesis' components exposed to tribological wear.
Originality/value
This paper presents the friction and wear behaviour of the lumbar IDE prototype. The tests were carried out in motion and loading conditions close to those we observe in the lumbar spine.
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Sarbjit Kaur, Niraj Bala and Charu Khosla
The biomaterials are natural or synthetic materials used to improve quality of life either by replacing tissue/organ or assisting their function in medical field. The purpose of…
Abstract
Purpose
The biomaterials are natural or synthetic materials used to improve quality of life either by replacing tissue/organ or assisting their function in medical field. The purpose of the study is to analyze the hydroxyapatite (HAP), HAP-TiO2 (25 percent) composite coatings deposited on 316 LSS by High Velocity Flame Spray (HVFS) technique.
Design/methodology/approach
The coatings exhibit almost uniform and dense microstructure with porosity (HAP = 0.153 and HAP-TiO2 composite = 0.138). Electrochemical corrosion testing was done on the uncoated and coated specimens in Ringer solution (SBF). As-sprayed coatings were characterized by XRD, SEM/EDS and cross-sectional X-ray mapping techniques before and after dipping in Ringer solution. Microhardness of composite coating (568.8 MPa) was found to be higher than HAP coating (353 MPa).
Findings
During investigations, it was observed that the corrosion resistance of steel was found to have increased after the deposition of HAP and HAP-TiO2 composite coatings. Thus, coatings serve as an effective diffusion barrier to prohibit the diffusion of ions from the SBF into the substrate. Composite coatings have been found to be more corrosion resistant as compared to HAP coating in the simulated body fluid.
Research limitations/implications
It has been concluded that corrosion resistance of HAP as well as composite coating is because of the desirable microstructural changes such as low porosity high microhardness and flat splat structures in coatings as compared to bare specimen.
Practical implications
This study is useful in the selection of biomedical implants.
Social implications
This study is useful in the field of biomaterials.
Originality/value
No reported literature on corrosion behavior of HAP+ 25%- TiO2 has been noted till now using flame spray technique. The main focus of the study is to investigate the HAP as well as composite coatings for biomedical applications.
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During the repair of compound skull fractures or penetrating wounds to the brain, removal of significant portions of the skull may be required. Conventional prefabricated…
Abstract
During the repair of compound skull fractures or penetrating wounds to the brain, removal of significant portions of the skull may be required. Conventional prefabricated alloplastic implants require the use of complicated procedures during surgery, which can endanger a patient. Since prior rehearsals of the surgery are next to impossible, the surgery is usually complicated and lengthy. This paper aims to outline the importance of rapid prototyping (RP) in medicine, and also it details the use of RP for a cranioplastic surgery that was conducted in the South East Asian region. RP offers an easier way to design customized implants and manufacture them within a very short period. Rapid Prototyping can be used as an effective tool to generate complex 3D medical models from computed tomographic (CT) images. The models can be used for didactic purposes, as it helps the surgeons plan and rehearse the surgery well in advance. The RP prototype was used to successfully complete a cranioplastic surgery and realize the desired results. The operation time was also significantly reduced.
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Deepkamal Kaur Gill, Kartikeya Walia, Aditi Rawat, Divya Bajaj, Vipin Kumar Gupta, Anand Gupta, Mamta Juneja, Rakesh Tuli and Prashant Jindal
To relieve intracranial pressure and save patient inflicted with severe head injury, neurosurgeons restore cranial defects. These defects can be caused because of trauma or…
Abstract
Purpose
To relieve intracranial pressure and save patient inflicted with severe head injury, neurosurgeons restore cranial defects. These defects can be caused because of trauma or diseases (Osteomyelitis of bone) which are treated by cranioplasty, using the preserved bone of patient. In case of non-availability of bone, a cranial implant is generated using a biocompatible synthetic material, but this process is less accurate and time-consuming. Hence, this paper aims to present the use of rapid prototyping technology that allows the development of a more accurate patient-specific template and saves the surgery time.
Design/methodology/approach
A five-year-old girl patient having cranial defect was taken up for cranioplasty. CT (computed tomography) scans of the patient were used to generate 3D design of the implant suitable to conceal the defect on the left frontal portion using CAD/CAM (computer-aided design/ computer-aided manufacturing) software. The design was used for 3D printing to manufacture a base template, which was finally used to fabricate the actual implant using Simplex® P bone cement material to conceal the defect.
Findings
Surgery using Simplex® P implant was performed successfully on the patient, giving precise natural curvature to left frontal portion of the patient, decreasing surgery time by about 30 per cent.
Originality/value
The case demonstrates the development of a convenient, time-saving and aesthetically superior digital procedure to treat cranial defect in the absence of preserved bone flap using CT scan as input. 3D modelling and printing were deployed to produce an accurate template which was used to generate an implant using bone cement biocompatible material.
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Changjun Chen, Yang Li, Min Zhang, Xiaonan Wang, Chao Zhang and Hemin Jing
Additive manufacturing (AM), a method used in the nuclear, space and racing industries, allows the creation of customized titanium alloy scaffolds with highly defined external…
Abstract
Purpose
Additive manufacturing (AM), a method used in the nuclear, space and racing industries, allows the creation of customized titanium alloy scaffolds with highly defined external shape and internal structure using rapid prototyping as supporting external structures within which bone tissue can grow. AM allows porous tantalum parts with mechanical properties close to that of bone tissue to be obtained.
Design/methodology/approach
In this paper, porous tantalum structures with different scan distance were fabricated by AM using laser multi-layer micro-cladding.
Findings
Porous tantalum samples were tested for resistance to compressive force and used scanning electron microscope to reveal the morphology of before and after compressive tests. Their structure and mechanical properties of these porous Ta structures with porosity in the range of 35.48 to 50 per cent were investigated. The porous tantalum structures have comparable compressive strength 56 ∼ 480 MPa, and elastic modulus 2.8 ∼ 9.0GPa, which is very close to those of human spongy bone and compact bone.
Research limitations/implications
This paper does not demonstrate the implant results.
Practical implications
It can be used as implant material for the repair bone.
Social implications
It can be used for fabrication of other porous materials.
Originality/value
This paper system researched the scan distance on how to influence the mechanical properties of fabricated porous tantalum structures.
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Murtdha Adhab Siyah, Rostam Moradian and Iraj Manouchehri
SS316L alloy used in biomedical application and the alloy have Fe, Cr and Ni elements and release this ion into the human body causing dangerous effects for the human body, and…
Abstract
Purpose
SS316L alloy used in biomedical application and the alloy have Fe, Cr and Ni elements and release this ion into the human body causing dangerous effects for the human body, and make the SS316L, which is used as surgical implant failure in short time in biomedical application. This study aims to use Ti6Al4V as coating for SS316L alloy to make it have bio inert surface, and modified the surface alloy for biomedical application from another part in this study, we want to decrease the corrosion rate for SS316L in simulated body surface Ringer solution.
Design/methodology/approach
The morphology, roughness, XRD of the coating, potential polarization and electrochemical impedance spectra investigation to study the effect of Ti6Al4V coating on corrosion behaviors of SS316L in the Ringer solution.
Findings
This study discusses the modification of SS316L surfaces by using Ti6Al4V radio magnetron frequency sputtering techniques, the results of the EIS and polarization of SS316L in Ringer’s solution at 37°C shows that improved resistance against corrosive ions for all the samples coating with Ti6Al4V and especially with a coating have a thickness of 850 nm at a sputtering power of 150 W.
Research limitations/implications
Polarization and electro chemical impedance spectra were assessed to investigate the effect of Ti6Al4V coating on corrosion behaviors of SS316L alloy in the Ringer solution.
Practical implications
This study discussed the modification SS316L surfaces by using Ti6Al4V radio magnetron frequency sputtering techniques. The results of the EIS and polarization of SS316L in Ringer’s solution at 37°C improved resistance against corrosive ions for all the samples coating with a Ti6Al4V and specificity with the coating sample have a thickness 850 nm at a sputtering power of 150 W.
Social implications
The goal of this study to modification SS316L alloy surface by using Ti6al4V RF Sputtering to give the SS316L alloy more resistance for biocorrosion.
Originality/value
In this research, Ti6Al4V RF sputtering as a coating for SS316L, study the bio corrosion behaviors in Simulated body fluid Ringer solution and investigation the corrosion by using EIS analysis.
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Zuhao Li, Chenyu Wang, Chen Li, Zhonghan Wang, Fan Yang, He Liu, Yanguo Qin and Jincheng Wang
This paper aims to review the latest applications in terms of three-dimensional printed (3DP) metal implants in orthopedics, and, importantly, the design of 3DP metal implants…
Abstract
Purpose
This paper aims to review the latest applications in terms of three-dimensional printed (3DP) metal implants in orthopedics, and, importantly, the design of 3DP metal implants through a series of cases operated at The Second Hospital of Jilin University were presented.
Design/methodology/approach
This paper is available to practitioners who are use 3DP implants in orthopedics. This review began with the deficiency of traditional prostheses and basic concepts of 3DP implants. Then, representative 3DP clinical cases were summarized and compared, and the experiences using customized prostheses and directions for future potential development are also shown.
Findings
The results obtained from the follow-up of clinical applications of 3DP implants show that the 3D designed and printed metal implants could exhibit good bone defect matching, quick and safe joint functional rehabilitation as well as saving time in surgery, which achieved high patient satisfaction collectively.
Originality/value
Single center experiences of 3DP metal implants design were shared and the detailed technical points between various regions were compared and analyzed. In conclusion, the 3DP technology is infusive and will present huge potential to reform future orthopedic practice.
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