The Application and Operation-Effect Analysis for Complex Tibial Plateau Fractures with 3D Printing Technique

Objective: To investigate the value of 3D printing techniques in the treatment of complex tibial plateau fractures. Methods: From September 2016 to September 2018, 28 patients with complex tibial plateau fractures were treated in our hospital. According to the odevity of hospitalized order, the patients were divided into two groups. Group A used 3D reconstruction, virtually reduction, 3D printing and demonstration of individual fracture model before operation while group B only received conventional process by use X-rays or CT image. Comparison between the two groups was made in operation time, operative blood loss, radiation frequency, surgery instrument cost and knee function score. Results: The follow-up was 14.4 months on average (ranged 6 to 22 months). There was no statistical difference of the surgery instrument cost between the 2 groups (P > 0.05). The operation time of group A was significantly shorter than that of group B (P χ2 = 0.373, P = 0.54). Conclusion: 3D printing techniques can improve surgery effect in complex tibial plateau fractures.

Permittivity of composites used for Luneburg lens antennas by drilling holes based on 3-D printing technique

Due to the attractive performances such as the ability of beam focus,broadband,multi-beam scanning and other features,Luneburg lens antennas are applied in multi-beam antenna,which overcomes the problem of gain loss produced by multi-beam parabolic antenna.Based on 3-D printing technique,Luneburg lens antennas by drilling holes are studied.Permittivity and loss tangent of the equivalent lens materials can be influenced by original materials,hole shapes,hole directions,and porosity.After tests,polystyrene with waxes may be the most appropriate materials for Luneburg lens with high strength.Permittivity with the shape of triangle is the lowest due to the homogeneity.Relative permittivities with the direction at a range of 15°-45°are lower while loss tangent at a range of 0°-30°.Radial directional holes are more appropriate for Luneburg lens.The relative permittivity is decreased with the increment of porosity.After calculations,the forecasts calculated by Looyenga and A-BG theory are more precise.Finally,Luneburg lens with two layers is fabricated by 3-D printing.

Phase II Clinical Study of Three-Dimensional Printed Coplanar Template Combined with CT-Guided Percutaneous Core Needle Biopsy of Pulmonary Nodules in Elderly Patients

Background: As the population age structure gradually ages, more and more elderly people were found to have pulmonary nodules during physical examinations. Most elderly people had underlying diseases such as heart, lung, brain and blood vessels and cannot tolerate surgery. Computed tomography (CT)-guided percutaneous core needle biopsy (CNB) was the first choice for pathological diagnosis and subsequent targeted drugs, immune drugs or ablation treatment. CT-guided percutaneous CNB requires clinicians with rich CNB experience to ensure high CNB accuracy, but it was easy to cause complications such as pneumothorax and hemorrhage. Three-dimensional (3D) printing coplanar template (PCT) combined with CT-guided percutaneous pulmonary CNB biopsy has been used in clinical practice, but there was no prospective, randomized controlled study. Methods: Elderly patients with lung nodules admitted to the Department of Oncology of our hospital from January 2019 to January 2023 were selected. A total of 225 elderly patients were screened, and 30 patients were included after screening. They were randomly divided into experimental group (Group A: 30 cases) and control group (Group B: 30 cases). Group A was given 3D-PCT combined with CT-guided percutaneous pulmonary CNB biopsy, Group B underwent CT-guided percutaneous pulmonary CNB. The primary outcome measure of this study was the accuracy of diagnostic CNB, and the secondary outcome measures were CNB time, number of CNB needles, number of pathological tissues and complications. Results: The diagnostic accuracy of group A and group B was 96.67% and 76.67%, respectively (P = 0.026). There were statistical differences between group A and group B in average CNB time (P = 0.001), number of CNB (1 vs more than 1, P = 0.029), and pathological tissue obtained by CNB (3 vs 1, P = 0.040). There was no statistical difference in the incidence of pneumothorax and hemorrhage between the two groups (P > 0.05). Conclusions: 3D-PCT combined with CT-guided percutaneous CNB can improve the puncture accuracy of elderly patients, shorten the puncture time, reduce the number of punctures, and increase the amount of puncture pathological tissue, without increasing pneumothorax and hemorrhage complications. We look forward to verifying this in a phase III randomized controlled clinical study. .

A combination of digital design and three-dimensional printing to assist treatment of thoracolumbar compression fractures using percutaneous kyphoplasty

Objective:To evaluate the clinical efficacy of the preoperative digita1 design combined with three dimensional(3D)printing models to assist percutaneous kyphoplasty(PKP)treatment for thoracolumbar compression frac tures.Methods:From January 2018 to August 2020,we obtained data of 99 patients diagnosed thoracolumbar compression fractures.These patients were divided into control group(n=50)underwent traditional PKP surgery,and observation group(n=49)underwent preoperative digital design combined with 3D printing model assisted PKP treatment.The clinical efficacy was evaluated with five parameters,including operation time,number of intraoperative radiographs,visual analogue scale(VAS)score,Cobb Angle change,and high compression rate of injured vertebrae.Results:There were statistically significant differences of operation time and number of intraoperative radio graphs between the two groups(P<0.05).For VAS score,Cobb Angle change and vertebral height compression rate,all of these three parameters were significantly improved when the patients accepted surgery teatment in two groups(P<0.05).However,there were no significant differences between control group and observation group for these three parameters either before or after surgery(P>0.05).Conclusions:Through the design of preoperative surgical guide plate and the application of 3D printing model to guide the operation,the precise design of preoperative surgical puncture site and puncture Angle of the injured vertebra was realized,the number of intraoperative radiographs was reduced,the operation time was shortened and the operation efficiency was improved.

Experimental investigation on the invert stability of operating railway tunnels with different drainage systems using 3D printing technology

In recent years, the invert anomalies of operating railway tunnels in water-rich areas occur frequently,which greatly affect the transportation capacity of the railway lines. Tunnel drainage system is a crucial factor to ensure the invert stability by regulating the external water pressure(EWP). By means of a threedimensional(3D) printing model, this paper experimentally investigates the deformation behavior of the invert for the tunnels with the traditional drainage system(TDS) widely used in China and its optimized drainage system(ODS) with bottom drainage function. Six test groups with a total of 110 test conditions were designed to consider the design factors and environmental factors in engineering practice,including layout of the drainage system, blockage of the drainage system and groundwater level fluctuation. It was found that there are significant differences in the water discharge, EWP and invert stability for the tunnels with the two drainage systems. Even with a dense arrangement of the external blind tubes, TDS was still difficult to eliminate the excessive EWP below the invert, which is the main cause for the invert instability. Blockage of drainage system further increased the invert uplift and aggravated the track irregularity, especially when the blockage degree is more than 50%. However, ODS can prevent these invert anomalies by reasonably controlling the EWP at tunnel bottom. Even when the groundwater level reached 60 m and the blind tubes were fully blocked, the invert stability can still be maintained and the railway track experienced a settlement of only 1.8 mm. Meanwhile, the on-site monitoring under several rainstorms further showed that the average EWP of the invert was controlled within 84 k Pa, while the maximum settlement of the track slab was only 0.92 mm, which also was in good agreement with the results of model test.

The application of 3D printing in the development of RECIST standard for evaluating tumor efficacy

Three-dimensional(3D)printing technology,as a novel technical method,can convert conventional computed tomography(CT)or magnetic resonance imaging(MRI)scans to computer-aided design files and develop a 2D spatial structure into a 3D imaging structure.In recent years,the technology has been widely used in numerous areas,including head and neck surgery,orthopedics,and bio-medicinal research.This article uses examples of 3D printed tumor models to develop Response Evaluation Criteria In Solid Tumors(RECIST)standards to evaluate the changes in tumors.RECIST standard is currently recognized as the standard for assessment of chemotherapy.Under the RECIST standard,changes occurring in tumors before and after the surgery,are evaluated.The assessment depends upon a CT evaluation of the changes in the lesions with the largest diameters.In addition,the disease progression and stability of remission is also assessed.Three-dimensional printing technology is more intuitive in the evaluation of changes to human tumors following chemotherapy and targeted therapy.However,a few reports are available.

3D-printed “fistula stent” designed for management of enterocutaneous fistula: An advanced strategy

Enterocutaneous fistulas(ECFs) are great challenges during the open abdomen. The loss of digestive juice, water-electrolyte imbalance and malnutrition are intractable issues during management of ECF. Techniques such as "fistula patch" and vacuumassisted closure therapy have been applied to prevent contamination of open abdominal wounds by intestinal fistula drainage. However, failures are encountered due to high-output fistula and anatomical complexity. Here, we report 3 D-printed patient-personalized fistula stent for ECF treatment based on 3 D reconstruction of the fistula image. Subsequent follow-up demonstrated that this stent was well-implanted and effective to reduce the volume of enteric fistula effluent.

Application of a 3D-printed ”fistula stent” in plugging enteroatmospheric fistula with open abdomen: A case report

BACKGROUND Open abdomen(OA) has been generally accepted for its magnificent superiority and effectiveness in patients with severe trauma, severe intra-abdominal infection, and abdominal compartment syndrome. In the meantime, OA calls for a mass of nursing and the subsequent enteroatomospheric fistula(EAF), which is one of the most common complications of OA therapy, remains a thorny challenge.CASE SUMMARY Our team applied thermoplastic polyurethane as a befitting material for producing a 3 D-printed "fistula stent" in the management of an EAF patient,who was initially admitted to local hospital because of abdominal pain and distension and diagnosed with bowel obstruction. After a series of operations and OA therapy, the patient developed an EAF.CONCLUSION Application of this novel "fistula stent" resulted in a drastic reduction in the amount of lost enteric effluent and greatly accelerated rehabilitation processes.

Research progress of localization technique assisted neuroendoscopy for cerebral hemorrhage

Neurosurgeons who perform intracere-bral hemorrhage(ICH)evacuation procedures have lim-ited options for monitoring hematoma evacuation and intraoperatively assessing residual-hematoma burden.In recent years,neuroendoscope-assisted,minimally inva-sive surgery for spontaneous ICH is simple and effective and becoming increasingly common.Many methods are applied in neuronavigation-assisted surgery for ICH evac-uation,such as neuroendoscopy,three-dimensional(3D)reconstruction,intraoperative ultrasound,and stereotac-tic craniotomy.Compared with a traditional craniotomy operation,hematoma removal(using methods of accurate localization)can reduce iatrogenic damage,protect white matter,and shorten patients’recovery time.This paper mainly outlines the treatment of basal ganglia-cerebral hemorrhage with neuroendoscopy assistance using local-ization techniques.

Determination of the full-field stress and displacement using photoelasticity and sampling moirémethod in a 3D-printed model

The quantitative characterization of the full-field stress and displacement is significant for analyzing the failure and instability of engineering materials.Various optical measurement techniques such as photoelasticity,moiréand digital image correlation methods have been developed to achieve this goal.However,these methods are difficult to incorporate to determine the stress and displacement fields simultaneously because the tested models must contain particles and grating for displacement measurement;however,these elements will disturb the light passing through the tested models using photoelasticity.In this study,by combining photoelasticity and the sampling moirémethod,we developed a method to determine the stress and displacement fields simultaneously in a three-dimensional(3D)-printed photoelastic model with orthogonal grating.Then,the full-field stress was determined by analyzing 10 photoelastic patterns,and the displacement fields were calculated using the sampling moirémethod.The results indicate that the developed method can simultaneously determine the stress and displacement fields.

Inner damage identification and residual strength assessment of a 3D printed tunnel with marble-like cementitious materials using piezoelectric transducers

Quantitative damage identification of surrounding rock is important to assess the current condition and residual strength of underground tunnels.In this work,an underground tunnel model with marble-like cementitious materials was first fabricated using the three-dimensional(3D)printing technique and then loaded to simulate its failure mode in the laboratory.Lead zirconate titanate piezoelectric(PZT)transducers were embedded in the surrounding rock around the tunnel in the process of 3D printing.A 3D monitoring network was formed to locate damage areas and evaluate damage extent during loading.Results show that as the load increased,main cracks firstly appeared above the tunnel roof and below the floor,and then they coalesced into the tunnel boundary.Finally,the tunnel model was broken into several parts.The resonant frequency and the peak of the conductance signature firstly shifted rightwards with loading due to the sealing of microcracks,and then shifted backwards after new cracks appeared.An overall increase in the root-mean-square deviation(RMSD)calculated from conductance signatures of all the PZT transducers was observed as the load(damage)increased.Damage-dependent equivalent stiffness parameters(ESPs)were calculated from the real and imaginary signatures of each PZT at different damage states.Satisfactory agreement between equivalent and experimental ESP values was achieved.Also,the relationship between the change of the ESP and the residual strength was obtained.The method paves the way for damage identification and residual strength estimation of other 3D printed structures in civil engineering.

3D打印整体复制技术在脑动脉瘤手术治疗中的应用

目的探讨3D打印整体复制技术在脑动脉瘤手术治疗中的应用价值。方法 2017年2月至2019年2月收治符合标准的脑动脉瘤54例,根据术前规划分为观察组(27例)和对照组(27例)。对照组按常规进行计划实施手术。观察组术前应用颅脑整体3D打印模型进行动脉瘤手术模拟。结果两组均顺利完成手术治疗。观察组术中显露时间[(123.3±74.9)min]显著短于对照组[(219.8±121.4)min,P<0.05]。两组住院时间无明显差异(P>0.05)。观察组术后6个月GOS评分[(4.33±0.25)分]、手术前后NIHSS评分差值[(5.85±3.84)分]、Barthrl指数差值[(17.50±4.56)分]均显著大于对照组[分别为(2.86±0.12)分、(3.30±3.53)分、(10.00±5.31)分;P<0.05]。两组术后并发症发生率无明显差异(P>0.05)。结论 3D整体打印模型辅助制定手术计划,可缩短脑动脉瘤术中显露时间,同时改善病人预后。

3D打印结合虚拟手术辅助治疗C型桡骨远端骨折

目的探讨3D打印结合虚拟手术辅助治疗C型桡骨远端骨折手术的效果。方法将17例C型桡骨远端骨折患者术前薄层CT扫描的数据适当处理后导入3D打印机,快速定制模型以分析骨折具体情况,同时在计算机上进行虚拟的复位内固定手术后,制定详细的手术计划。严格按照计划实施手术,记录手术时间、术中出血量、骨折愈合时间、复位情况和腕关节功能恢复情况。结果手术时间28～76 min,术中出血量20～75 ml。患者均获得随访,时间6～18个月。骨折全部愈合,时间为8.2～11.5周。术后6个月时,影像学测量桡骨高度为7.2～12.7 mm,掌倾角为7.1°～14.9°,尺偏角14.8°～27.3°;采用改良Sarmiento系统评估骨折复位情况:优10例,良6例,可1例;采用Dienst标准评估腕关节功能:优12例,良4例,可1例。结论借助3D打印技术快速定制骨折模型,术者可以直观、深入地观察C型桡骨远端骨折情况;通过计算机数字化虚拟手术,按照定制的术前计划实施精准手术,可以提高实际手术的效率,提高治疗效果满意度。

Physical model test and application of 3D printing rock-like specimens to laminated rock tunnels

Weak structural plane deformation is responsible for the non-uniform large deformation disasters in layered rock tunnels,resulting in steel arch distortion and secondary lining cracking.In this study,a servo biaxial testing system was employed to conduct physical modeling tests on layered rock tunnels with bedding planes of varying dip angles.The influence of structural anisotropy in layered rocks on the micro displacement and strain field of surrounding rocks was analyzed using digital image correlation(DIC)technology.The spatiotemporal evolution of non-uniform deformation of surrounding rocks was investigated,and numerical simulation was performed to verify the experimental results.The findings indicate that the displacement and strain field of the surrounding layered rocks are all maximized at the horizontal bedding planes and decrease linearly with the increasing dip angle.The failure of the layered surrounding rock with different dip angles occurs and extends along the bedding planes.Compressive strain failure occurs after excavation under high horizontal stress.This study provides significant theoretical support for the analysis,prediction,and control of non-uniform deformation of tunnel surrounding rocks.

汽车发动机连杆激光3-D打印工艺研究

为了研究汽车发动机连杆激光3-D打印制造工艺,采用理论分析和实验验证的方法,建立了连杆3-D数据模型,进行了分层切片处理,通过S型扫描和轮廓偏移扫描,规划两种连杆加工路径。选用铁基合金粉末以及相应的工艺参量,在激光3-D打印系统中进行连杆打印试验。扫描单层轨迹用时4min30s^4min56s,总用时4h20min。结果表明,连杆成形区底部的金相组织主要是柱状晶和树枝晶,中上部是细小的等轴晶,层间致密搭接,形成良好的冶金结合;成形连杆显微硬度为450HV^490HV,屈服强度为754MPa,抗拉强度为1189MPa,延伸率为9%。连杆激光3-D打印成形制坯性能相比于锻造、粉锻制造工艺,减少了工装成本支出并缩短了生产准备工时,其屈服强度、抗拉强度等力学性能超过钢锻连杆,与国外粉锻连杆相比,差别不大,能满足连杆制坯要求。

金属3-D打印制造技术的发展

归纳了当前金属3-D打印技术的发展情况,指出了各类3-D打印技术优缺点,从发展历史、工作原理等方面讨论了典型3-D打印技术的技术特点;在此基础上,对选区激光熔化技术的研究前景进行展望,即激光选区熔化技术作为金属3-D打印一个重要分支在各领域具有更广泛的应用;提高材料性能、设备功能、结构设计及制造工艺的研发水平,可极大推动金属3-D打印技术的发展。随着金属打印技术的成熟,3-D打印的应用必将会覆盖更多金属制造产业,成为未来最重要、最具战略意义的制造技术。

3D printing of glass by additive manufacturing techniques:a review

Additive manufacturing(AM),which is also known as three-dimensional(3D)printing,uses computer-aided design to build objects layer by layer.Here,we focus on the recent progress in the development of techniques for 3D printing of glass,an important optoelectronic material,including fused deposition modeling,selective laser sintering/melting,stereolithography(SLA)and direct ink writing.We compare these 3D printing methods and analyze their benefits and problems for the manufacturing of functional glass objects.In addition,we discuss the technological principles of 3D glass printing and applications of 3D printed glass objects.This review is finalized by a summary of the current achievements and perspectives for the future development of the 3D glass printing technique.

Control of electromechanical performance in 3D printing latticestructured BaTiO_(3) piezoelectric ceramics

Barium titanate(BaTiO_(3))piezoelectric ceramics with triply periodic minimal surface(TPMS)structures have been frequently used in filters,engines,artificial bones,and other fields due to their high specific surface area,high thermal stability,and good heat dissipation.However,only a limited number of studies have analyzed the effect of various parameters,such as different wall thicknesses and porosities of TPMS structures,on ceramic electromechanical performance.In this study,we first employed vat photopolymerization(VPP)three-dimensional(3D)printing technology to fabricate high-performance BaTiO_(3) ceramics.We investigated the slurry composition design and forming process and designed a stepwise sintering postprocessing technique to achieve a density of 96.3%and a compressive strength of 250±25 MPa,with the piezoelectric coefficient(d_(33))reaching 263 pC/N.Subsequently,we explored the influence of three TPMS structures,namely,diamond,gyroid,and Schwarz P,on the piezoelectric and mechanical properties of BaTiO_(3) ceramics,with the gyroid structure identified as exhibiting optimal performance.Finally,we examined the piezoelectric and mechanical properties of BaTiO_(3) ceramics with the gyroid structure of varying wall thicknesses and porosities,thus enabling the modulation of ceramic electromechanical performance.

Photosensitizer-assisted direct 2D patterning and 3D printing of colloidal quantum dots

Direct photopatterning is a powerful strategy for patterning colloidal quantum dots(QDs)for their integration in various electronic and optoelectronic devices.However,ultraviolet(UV)exposure required for QD patterning,especially those with short wavelength(e.g.,deep UV light),can degrade the photo-,and electroluminescence,and other properties of patterned QDs.Here we develop a photosensitizer-assisted approach for direct photopatterning of QDs with h-line(centered at 405 nm)UV light and better preservation of their luminescent properties.This approach uses a photosensitizer that can absorb the h-line UV light and transfer the energy to activate bisazide-based crosslinkers via Dexter energy transfer.Uniform,high-resolution(smallest feature size,2μm),and full-color patterns of red,green,and blue QD layers can be achieved.The patterned QD layers maintain up to~90%of their original photoluminescent quantum yields,comparing favorably with those(<60%)of QDs patterned without photosensitizers.We further extended the strategy to the direct three-dimensional(3D)printing of QDs.This photosensitizerassisted approach offers a new way for direct two-dimensional(2D)photopatterning and 3D printing of colloidal QDs,with implications in building high-performance QD optoelectronic devices.

Nanoscale 3D Printing Technique Uses Micro-Pyramids to Build Better Biochips

This nanoprinting process allows researchers to 3D print more material on a biochip than ever before,making it easier to study biomedical issues.Making biochips,a key technology in studying disease,just got a little easier.This new nanoprinting process?uses gold-plated pyramids,an LED light,and photochemical reactions to print more organic material on the surface of one single biochip than ever before.The technique uses an array of polymer pyramids that are covered in gold and mounted onto an atomic force mi-