Three-dimensional Printing Research Articles

A Cost-Affordable Methodology of 3D Printing of Bone Fractures Using DICOM Files in Traumatology

Three-dimensional (3D) printing has gained popularity across various domains but remains less integrated into medical surgery due to its complexity. Existing literature primarily discusses specific applications, with limited detailed guidance on the entire process. The methodological details of converting Computed Tomography (CT) images into 3D models are often found in amateur 3D printing forums rather than scientific literature. To address this gap, we present a comprehensive methodology for converting CT images of bone fractures into 3D-printed models. This involves transferring files in Digital Imaging and Communications in Medicine (DICOM) format to stereolithography format, processing the 3D model, and preparing it for printing. Our methodology outlines step-by-step guidelines, time estimates, and software recommendations, prioritizing free open-source tools. We also share our practical experience and outcomes, including the successful creation of 72 models for surgical planning, patient education, and teaching. Although there are challenges associated with utilizing 3D printing in surgery, such as the requirement for specialized expertise and equipment, the advantages in surgical planning, patient education, and improved outcomes are evident. Further studies are warranted to refine and standardize these methodologies for broader adoption in medical practice.

Three-Dimensional Printing of Yttrium Oxide Transparent Ceramics via Direct Ink Writing.

The utilization of 3D printing technology for the fabrication of intricate transparent ceramics overcomes the limitations associated with conventional molding processes, thereby presenting a highly promising solution. In this study, we employed direct ink writing (DIW) to prepare yttrium oxide transparent ceramics using a ceramic slurry with excellent moldability, solid content of 45 vol%, and shear-thinning behavior. A successfully printed transparent yttrium oxide ring measuring 30 mm in diameter, 10 mm in inner diameter, and 0.9 mm in thickness was obtained from the aforementioned slurry. After de-binding and sintering procedures, the printed ceramic exhibited in-line transmittance of 71% at 850 nm. This work not only produced complex yttria transparent ceramics with intricate shapes, but also achieved in-line transmittance that was comparable to that of the CIP method (79%), which can meet certain optical applications.

Development of an accurate hand-held sensing platform for nitrite detection based on nitrogen-doped carbon dots

As is well known, excessive nitrite can seriously pollute the environment and can harm human health. Although existing methods can be used to determine nitrite content, they still have some drawbacks, such as relatively complicated operation and expensive equipment. Herein, a hand-held sensing platform (HSP) for NO2− determination was developed. First, ammonia-rich nitrogen-doped carbon dots with orange-yellow emission were designed and synthesised, which were suitable as fluorescent probes because of their good optical properties and stability. Then, the HSP based on fluorescence using photoelectric conversion technology was designed and manufactured using three-dimensional printing technology. Under optimum conditions, the voltage (V/V0) of the proposed HSP showed good linearity for NO2− detection in the range of 10–500 μM, with a detection limit of 1.95 μM. This portable sensor showed good stability, accuracy and reliability in detecting actual water and meat samples, which may ensure food safety in practical applications. Moreover, the HSP is compact, portable and easily assembled and is suitable for on-site real-time detection, which shows great application potential and prospects.

A Comparative Study of the Rheological Properties of a Fly Ash-Based Geopolymer Reinforced with PP Fiber for 3D Printing: An Experimental and Numerical Approach

The present study investigates the flow characteristics of fly ash-based (FA) geopolymers reinforced with polypropylene (PP) fibers during the extrusion process in three-dimensional printing. By applying the Herschel–Bulkley rheological model, this research provides a sound theoretical basis to understand the flow behavior of these materials under various conditions. The Herschel–Bulkley model describes the relationship between shear stress and the shear rate in non-Newtonian fluids, capturing yield stress and flow consistency. A combination of experimental and numerical techniques based on the Finite-Element Method (FEM) in COMSOL has been used in this study. The results of both experimental and simulation approaches are compared to examine the material behavior during extrusion. The experimental results indicate that PP fiber content significantly affects the rheological properties. Mixtures with high fiber content encountered issues such as high static yield. However, mixtures with moderate fiber content showed smoother extrusion processes, suggesting an optimal fiber addition range that balances mechanical properties and extrudability. The numerical simulations generally agreed with the experimental data up to a certain fiber content level, beyond which more complex interactions necessitate further model refinements. The investigation identified a 0.25% to 0.5% fiber content range that enhances performance without complicating the extrusion process, facilitating the production of properly printed structures.

Smart laser Sintering: Deep Learning-Powered powder bed fusion 3D printing in precision medicine

Medicines remain ineffective for over 50% of patients due to conventional mass production methods with fixed drug dosages. Three-dimensional (3D) printing, specifically selective laser sintering (SLS), offers a potential solution to this challenge, allowing the manufacturing of small, personalized batches of medication. Despite its simplicity and suitability for upscaling to large-scale production, SLS was not designed for pharmaceutical manufacturing and necessitates a time-consuming, trial-and-error adaptation process. In response, this study introduces a deep learning model trained on a variety of features to identify the best feature set to represent drugs and polymeric materials for the prediction of the printability of drug-loaded formulations using SLS. The proposed model demonstrates success by achieving 90% accuracy in predicting printability. Furthermore, explainability analysis unveils materials that facilitate SLS printability, offering invaluable insights for scientists to optimize SLS formulations, which can be expanded to other disciplines. This represents the first study in the field to develop an interpretable, uncertainty-optimized deep learning model for predicting the printability of drug-loaded formulations. This paves the way for accelerating formulation development, propelling us into a future of personalized medicine with unprecedented manufacturing precision.

An Advanced Knee Simulator Model Can Reproducibly Be Used for Ligament Balancing Training during Total Knee Arthroplasty.

A critical and difficult aspect of total knee arthroplasty (TKA) is ligamentous balancing for which cadavers and models have played a large role in the education and training of new arthroplasty surgeons, although they both have several shortcomings including cost, scarcity, and dissimilarity to in vivo ligament properties. An advanced knee simulator (AKS) model based on computed tomography (CT) scans was developed in the setting of these challenges with cadavers and previous models. In this study, we compared the ligament balancing between AKS and human cadaveric knees to assess the validity of using the AKS for ligament balancing training during TKA. A CT scan of a TKA patient with varus deformity was used to design the AKS model with modular components, using three-dimensional printing. Three fellowship-trained arthroplasty surgeons used technology-assisted TKA procedure to plan and balance three cadaver knees and the AKS model. Medial and lateral laxity data were captured using manual varus and valgus stress assessments for cadavers and the model in an extension pose (10 degrees of flexion from terminal extension) and between 90 and 95 degrees for flexion. After preresection assessments, surgeons planned a balanced cruciate-retaining TKA. Following bony cuts and trialing, extension and flexion ligament laxity values were recorded in a similar manner. Descriptive statistics and Student's t-tests were performed to compare the cadavers and model with a p-value set at 0.05. Preresection medial/lateral laxity data for both extension and flexion were plotted and showed that the highest standard deviation (SD) for the cadavers was 0.67 mm, whereas the highest SD for the AKS was 1.25 mm. A similar plot for trialing demonstrated that the highest SD for the cadavers was 0.6 mm, whereas the highest SD for the AKS was 0.61 mm. The AKS trialing data were highly reproducible when compared with cadaveric data, demonstrating the value of the AKS model as a tool to teach ligament balancing for TKA and for future research endeavors.

The comprehensive review on 3D printing- pharmaceutical drug delivery and personalized food and nutrition

Three-dimensional printing is one of the emerging technologies that is gaining interest from the pharmaceutical industry as it provides an opportunity to customize drugs according to each patient's needs. Combining different active pharmaceutical ingredients, using different geometries, and providing sustained release enhances the effectiveness of medicine. One of the most innovative uses of 3D printing is producing fabrics, medical devices, medical implants, orthoses, and prostheses. This review summarizes the various 3D printing techniques such as stereolithography, inkjet printing, thermal inkjet printing, fused deposition modelling, extrusion printing, semi-solid extrusion printing, selective laser sintering, and hot-melt extrusion. Also, discusses the drug relies profile and its mechanisms, characteristics, and applications of the most common types of 3D printed API formulations and its recent development. Here, Authors also, summarizes the central flow of 3D food printing process and knowledge extension toward personalized nutrition.

Advancement in computational simulation and validation of congenital heart disease: a review

The improvement in congenital heart disease (CHD) treatment and management has increased the life expectancy in infants. However, the long-term efficacy is difficult to assess and thus, computational modelling has been applied for evaluating this. Here, we provide an overview of the applications of computational modelling in CHD based on three categories; CHD involving large blood vessels only, heart chambers only, and CHD that occurs at multiple heart structures. We highlight the advancement of computational simulation of CHD that uses multiscale and multiphysics modelling to ensure a complete representation of the heart and circulation. We provide a brief future direction of computational modelling of CHD such as to include growth and remodelling, detailed conduction system, and occurrence of myocardial infarction. We also proposed validation technique using advanced three-dimensional (3D) printing and particle image velocimetry (PIV) technologies to improve the model accuracy.

Efficacy of 3D printed anatomically equivalent thermoplastic polyurethane guide conduits in promoting the regeneration of critical-sized peripheral nerve defects.

Three-dimensional (3D) printing is an emerging tool for creating patient-specific tissue constructs analogous to the native tissue microarchitecture. In this study, anatomically equivalent 3D nerve conduits were developed using thermoplastic polyurethane (TPU) by combining reverse engineering and material extrusion (i.e., fused deposition modeling) technique. Printing parameters were optimized to fabricate nerve-equivalent TPU constructs. The TPU constructs printed with different infill densities supported the adhesion, proliferation, and gene expression of neuronal cells. Subcutaneous implantation of the TPU constructs for three months in rats showed neovascularization with negligible local tissue inflammatory reactions and was classified as a non-irritant biomaterial as per ISO 10993-6. To perform in vivo efficacy studies, nerve conduits equivalent to rat's sciatic nerve were fabricated and bridged in a 10 mm sciatic nerve transection model. After four months of implantation, the sensorimotor function and histological assessments revealed that the 3D printed TPU conduits promoted the regeneration in critical-sized peripheral nerve defects equivalent to autografts. ThisstudyprovedthatTPU-based 3D printed nerve guidance conduits can be created to replicate the complicated features ofnaturalnerves that can promote the regeneration of peripheral nerve defects and also show the potential to be extended to several other tissues for regenerative medicine applications.&#xD.

Hardening properties and microstructure of 3D printed engineered cementitious composites based on limestone calcined clay cement

Comparison of three-dimensional (3D) printing and cast methods on the mechanical properties of cementitious materials is the basis for intelligent construction development. To achieve this, a series of experiments including the uniaxial tensile, compressive, flexural and interlayer bonding tests of mould-cast and 3D printed (3DP) specimens are conducted to investigate the effects of different preparation technologies on the microstructure and hardening properties of limestone calcined clay cement (LC3) based engineered cementitious composites (ECC). Results indicate that the tensile strength and strain capacity of the printed LC3-ECC decrease by 16.6%–22.7 % and 43.3%–54.6 % compared to the cast specimens, while it still possesses a strain capacity of 2 % and multiple cracking behaviour. The compressive and flexural properties of the printed LC3-ECC both show significant anisotropy, the maximum values of which are observed in the Z- and Y- directions, respectively. The interlayer bonding strength increases by 54.3%–91.9 % at 28 d compared to that at 7 d due to the hydration of LC3. The pore structure of the printed LC3-ECC is denser than that of the cast LC3-ECC, with more regular arrangement and finer size of pores. The macro-micro properties correlation analysis proves the better comprehensive performance of printed LC3-ECC relative to casted LC3-ECC, as well as reveals the relationship between pore structure and anisotropy. In terms of material sustainability, 3DP-LC3-ECC has a significant reduction in energy and carbon emissions compared to typical M45-ECC, contributing to the environmental development.

Homemade 3D-Printed Affordable and Practical Alternative Videolaryngoscope: First Step

Objective: Changing economic conditions make it difficult for clinics to access the medical devices they need. Videolaryngoscope is one of the devices needed in many units such as operating rooms, intensive care and emergency services. Our study aims to design a low-cost videolaryngoscope (VL) using three-dimensional printing technology and offer clinics a cost-effective alternative to traditional VLs. Materials and Methods: Initially, three-dimensional images were obtained from the website www.thingeverse.com to form the basis of the videolaryngoscope blade. The Ultimaker Cura 4.0 program (Ultimaker B.V. Netherlands, Utrecht) was used to create three-dimensional drawings of the handle and blade prints. This drawing was produced on a 3D printer using polylactic acid as raw material. Finally, the wireless camera with 1080p HD resolution was positioned on the handle and blade. 3DPVL was tested on an intubation mannequin by a group of 30 anesthesiologists, each with at least 4 years of experience. The intubation times of the participants and their satisfaction with this process were recorded. Results: In the study, the intubation times performed by 30 anesthesiologists on a mannequin were recorded. It was determined that the average intubation time for 3DPVL was 24.3 seconds. 90% of participants rated the experience as good or excellent. Similarly, satisfaction levels were rated as good or excellent by 60% of participants. Conclusion: The affordable and practical of production associated with 3DPVL make it a potentially viable alternative to traditional VLs for clinicians. In the second step, a case series focusing on easy airways is planned regarding our device. In later steps, randomized controlled studies are planned between our device and traditional VL in easy and difficult airways.

Impact of three-dimensional-printing technology guidance on surgical outcomes for retroperitoneal sarcoma: A propensity score-matched study.

The surgical treatment of retroperitoneal sarcoma (RPS) is highly challenging because of its complex anatomy. In this study, the authors compared the surgical outcomes of patients with RPS who underwent surgical resection guided by three-dimensional (3D) printing technology versus traditional imaging. This retrospective study included 251 patients who underwent RPS resection guided by 3D-printing technology or traditional imaging from January 2019 to December 2022. The main outcome measures were operative time, intraoperative blood loss, postoperative complications, and hospital stay. In total, 251 patients were enrolled in the study: 46 received 3D-printed navigation, and 205 underwent traditional surgical methods. Propensity score matching yielded 44 patients in the 3D group and 82 patients in the control group. The patients' demographics and tumor characteristics were comparable in the matched cohorts. The 3D group had significantly shorter operative time (median, 186.5 minutes [interquartile range (IQR), 130.0-251.3 minutes] vs. 210.0 minutes [IQR, 150.8-277.3 minutes]; p=.04), less intraoperative blood loss (median, 300.0 mL [IQR, 100.0-575.0 mL] vs. 375.0 mL [IQR, 200.0-925.0 mL]; p=.02), shorter postoperative hospital stays (median, 11.0 days [IQR, 9.0-13.0 days] vs. 14.0 days [IQR, 10.8-18.3 days]; p=.02), and lower incidence rate of overall postoperative complications than the control group (18.1% vs. 36.6%; p=.03). There were no differences with regard to the intraoperative blood transfusion rate, the R0/R1 resection rate, 30-day mortality, or overall survival. Patients in the 3D group had favorable surgical outcomes compared with those in the control group. These results suggest that 3D-printing technology might overcome challenges in RPS surgical treatment. The surgical treatment of retroperitoneal sarcoma (RPS) is highly challenging because of its complex anatomy. The purpose of this study was to investigate whether three-dimensional (3D) printing technology offers advantages over traditional two-dimensional imaging (such as computed tomography and magnetic resonance imaging) for guiding the surgical treatment of RPS. In a group of patients who had RPS, surgery guided by 3D-printing technology was associated with better surgical outcomes, including shorter operative time, decreased blood loss, shorter hospital stays, and fewer postoperative complications. These findings suggested that 3D-printing technology could help surgeons overcome challenges in the surgical treatment of RPS. 3D-printing technology has important prospects in the surgical treatment of RPS.

152 Three-Dimensional Printing Bespoke Polycaprolactone Tracheal Splint for Treatment of Tracheomalacia

Abstract Aim Tracheomalacia can be a fatal airway disease with limited treatment options. Three-dimensional (3D) printing has led to various patient-specific tracheal stents and splints. However, these are limited by mismatched stiffness and resulting granulation tissue formation and fibrosis. We aimed to develop a non-toxic and biodegradable polycaprolactone expandable tracheal splint by 3D printing. By fine-tuning mechanical properties, we hypothesised that the splint would match the native trachea and accommodate tracheal growth in tracheomalacia patients. Method We designed splints consisting of concave topological patterns with varying angles and aspect ratios. Fabrication occurred using polycaprolactone filaments in a 3D fuse deposition modelling printer. Uniaxial tensile studies were performed on splints to assess Young’s Modulus, Toughness, Ultimate strain, Strength, and Poisson ratio. Splints displaying optimal mechanical properties were tested for human lung fibroblast cell viability, proliferation, and morphology. Results On a mechanical testing rig, uniaxial tensile studies confirmed that splint designs with smaller angles and negative Poisson ratios of up to strains of 25%, better mimicked mechanical properties of native human trachea, accommodating tracheal growth. In vitro studies using these tracheal splints demonstrated successful human lung cell proliferation with low cell toxicity. Conclusions This study characterised 3D printed bespoke tracheal splints with various 2D structures, showing mechanical properties that match the native trachea. However, in vivo studies investigating cellular interactions on our splint must be performed to further evaluate the ability for endogenous tissue formation.

Optimizing surface finish in FDM-printed polycarbonate spur gears through abrasive flow finishing: insights from physics and material science perspectives

In recent times, the usage of polymers has experienced notable growth across diverse manufacturing sectors. Polymeric gears, integral to automation, material handling systems, toys, and household appliances, have become ubiquitous. Although additive manufacturing techniques, especially Three-Dimensional (3D) printing, offer versatile applications, they grapple with challenges, notably poor surface finishing attributed to layer accumulation. This work explores the field of abrasive flow machining (AFM) in experimental settings using FDM-printed polymeric gears. The AFM medium concoction involves coal ash powder as the foundational material, EDM oil as the carrier fluid, and the infusion of glycerin as additives. Rigorous investigations were undertaken to pinpoint the optimal viscosity of the AFM medium and refine process parameters with a central focus on enhancing surface quality. A Taguchi L9 Design of Experiment (DOE) was meticulously crafted for parameter optimization using the Minitab statistical software. The investigation established a functional relationship between the output parameter (surface roughness) and key input variables (layer thickness, abrasive percentage, abrasive mesh size, and finishing time). The maximum level of AFM media optimization was attained at 33% abrasive concentration, 220 abrasive mesh size, and 60% liquid synthesizer. Additionally, the results of the investigation showed that a media viscosity of 0.50 Pa-sec, layer thickness of 0.1, and culminating time of 45 min were the optimal values for the most % improvement in surface roughness. The initial surface roughness underwent a profound reduction from 12.30 μm to 0.30 μm, marking an exceptional improvement of 97.56%. This inquiry contributes significant insights into the refinement of AFM parameters for elevating the surface finish of FDM-printed polymeric gears, promising enhanced performance across diverse applications.

3D printable elastomers with exceptional strength and toughness.

Three-dimensional (3D) printing has emerged as an attractive manufacturing technique because of its exceptional freedom in accessing geometrically complex customizable products. Its potential for mass manufacturing, however, is hampered by its low manufacturing efficiency (print speed) and insufficient product quality (mechanical properties). Recent progresses in ultra-fast 3D printing of photo-polymers1-5 have alleviated the issue of manufacturing efficiency, but the mechanical performance of typical printed polymers still falls far behind what is achievable with conventional processing techniques. This is because of the printing requirements that restrict the molecular design towards achieving high mechanical performance. Here we report a 3D photo-printable resin chemistry that yields an elastomer with tensile strength of 94.6 MPa and toughness of 310.4 MJ m-3, both of which far exceed that of any 3D printed elastomer6-10. Mechanistically, this is achieved by the dynamic covalent bonds in the printed polymer that allow network topological reconfiguration. This facilitates the formation of hierarchical hydrogen bonds (in particular, amide hydrogen bonds), micro-phase separation and interpenetration architecture, which contribute synergistically to superior mechanical performance. Our work suggests a brighter future for mass manufacturing using 3D printing.

Stapler Strategies for Upcycling Mixed Plastics.

Mechanical recycling is one of the simplest and most economical strategies to address ever-increasing plastic pollution, but it cannot be applied to immiscible mixed plastics and suffers from property deterioration after each cycle. By combining the amphiphilic block copolymer strategy and reactive compatibilization strategy, we designed a series of stapler strategies for compatibilizing/upcycling mixed plastics. First, various functionalized graft copolymers were accessed via different synthetic routes. Subsequently, the addition of a very small amount of stapler molecules induced a synergistic effect with the graft copolymers that improved the compatibility and mechanical properties of mixed plastics. These strategies were highly effective for various binary/ternary plastic systems and can be directly applied to postconsumer waste plastics, which can increase the toughness of mixed postconsumer waste plastics by 162 times. Most importantly, it also effectively improved the impact resistance, adhesion performance, and three-dimensional (3D) printing performance of mixed plastics, and permitted the recycling of plastic blends 20 times with minimal degradation in their mechanical properties.

Three-Dimensional Printing Creates New Trends of the Technological Revolution in Urologic Surgery

Three-Dimensional Printing Creates New Trends of the Technological Revolution in Urologic Surgery

From Imaging to Visualization: Seeing the Future of Endometriosis Care

ObjectiveTo describe how the knowledge from standard imaging practices can be translated into three-dimensional visualization techniques and utilized in the surgical planning and management of endometriosis. SettingTertiary care academic centre. ParticipantsTwo case studies of patients with endometriosis are described. InterventionsTransvaginal ultrasound (1), magnetic resonance imaging, three-dimensional printing (2), and three-dimensional virtual reality modeling (3) were utilized during patient workup and preparation. Three-dimensional modeling was performed by a virtual reality technician and verified for accuracy by a fellowship trained radiologist. Surgical management for endometriosis was performed. ConclusionWhile expert transvaginal ultrasound and/or magnetic resonance imaging suffice for the majority of cases, three-dimensional printing and virtual reality modeling are a novel adjunct to standard imaging modalities. Rendering two-dimensional images into a three-dimensional representation allows users to interact with the anatomy and is particularly useful when distorted by complex pathology. These techniques contributed to improved patient understanding and experience, and helped medical learners better grasp regular imaging techniques and its translation to pelvic anatomy. Last, it augmented surgeon comprehension of the relationship between the pelvic structures, allowing for enhanced surgical planning and intraoperative decision making. Further study is being performed to quantify these effects.

Mathematical modeling and experiments on the acoustic properties of a frame structure with a membrane

This study is a fundamental work conducted to theoretically estimate the acoustic properties of a simplified frame structure, that is, a simplified foam sound absorbing material, which is a porous material. The changes in the sound absorption characteristics caused by the presence of a membrane are also considered as part of the fundamental study of foam materials. In the mathematical model, the clearance composed by the frame structure with the membrane is divided into elements perpendicular to the direction of the soundwave incidence and approximated as a clearance bounded by two parallel planes. The characteristic impedance and the propagation constant are obtained for the approximated clearance and introduced into a one-dimensional transfer matrix. The transfer matrix method is used to calculate the sound absorption coefficient. The calculated theoretical values are compared with the experimental values. Sensitivity analysis is also performed for the changes in the parameters used in the theoretical analysis, such as the cylinder diameter and the pitch between the cylinders. The samples are fabricated using a three-dimensional printer. The sound absorption coefficient is measured using a two-microphone impedance measurement tube. The theoretical values based on the analysis tended to be close to the experimental ones. They showed a high prediction accuracy with respect to the peak frequency of the sound absorption curve. These values for the presence and increase of the membrane closely followed the experimental values when the percentage of the membrane present was varied.

Advancements and Applications of Three-dimensional Printing Technology in Surgery.

Three-dimensional (3D) printing technology has revolutionized surgical practices, offering precise solutions for planning, education, and patient care. Surgeons now wield tangible, patient-specific 3D models derived from imaging data, allowing for meticulous presurgical planning. These models enhance surgical precision, reduce operative times, and minimize complications, ultimately improving patient outcomes. The technology also serves as a powerful educational tool, providing hands-on learning experiences for medical professionals and clearer communication with patients and their families. Despite its advantages, challenges such as model accuracy and material selection exist. Ongoing advancements, including bioactive materials and artificial intelligence integration, promise to further enhance 3D printing's impact. The future of 3D printing in surgery holds potential for regenerative medicine, increased global accessibility, and collaboration through telemedicine. Interdisciplinary collaboration between medical and engineering fields is crucial for responsible and innovative use of this technology.