3D打印技术在临床医学中的应用进展

近年来,3D打印技术迅速发展,在临床医学领域尤其在与再生重建相关的外科中应用广泛。3D打印技术可用于制备医学模型,进行手术策划,手术辅助器械和个性化内植入物,生物打印与组织工程等方面。本综述着重介绍了3D打印技术在临床医学中的应用,并分析目前存在的问题及展望发展前景。     

3D打印PEEK材料血管外支架建模及制作方法的可行性和有效性

目的 证明用于治疗胡桃夹综合征的3D打印聚醚醚酮（PEEK）材料血管外支架的三维建模和制作方法的可行性和有效性。 方法 以37例胡桃夹综合征患者为对象，利用患者的CT影像数据，分别对左肾静脉（LRV）受压迫处的动脉和静脉部分进行三维重建并进行3D打印。根据患者动静脉三维数字模型设计血管外支架，并利用PEEK材料进行3D打印。将3D打印PEEK材料血管外支架在1:1动静脉模型上模拟置入并进行术前规划。利用T检验对比分析患者术前和术后3个月的复查数据。 结果 术前CT影像上测得LRV狭窄处直径均值为（2.81 ± 1.67） mm，动静脉三维数字模型上测得其均值为（2.85 ± 1.59）mm，误差绝对值为（0.17 ± 0.21）mm。患者术前与术后3个月复查结果显示，LRV狭窄处直径（P < 0.01）、LRV肾门处直径与狭窄处比值（P < 0.01）以及LRV肾门处血流速度（P ＜ 0.05）均有显著性差异。37位患者术后均无并发症，其中有22位症状完全消失，15位症状明显缓解。CT影像显示支架位置稳定，无移位。 结论 用于治疗胡桃夹综合征的3D打印PEEK材料血管外支架的建模及制作程序可行且有效。     

数字化3D打印技术在口腔医学中的临床应用进展

数字化3D打印是医疗卫生行业发展迅速的一项技术，在口腔临床医学领域表现出巨大潜力，包括牙体牙髓病学、口腔修复学、正畸学、颌面外科和口腔种植学。新型数字化3D打印可以辅助设计并制作个性化导板、模型、假体和生物支架等，具有高精准、微创化、操作时长短和工作效率高等优点。借助医理工多学科交叉和数字化程序辅助设计，数字化3D打印技术可为口腔疾病的预防和诊疗提供更具个性化和多元化的方案或策略。对数字化3D打印技术在口腔医学各个领域的临床应用进行总结，可为不同的口腔临床医学领域应用数字化3D打印技术提供参考依据。     

3D打印聚醚醚酮材料在颅脑损伤后颅骨成形术中的应用疗效分析

目的对比分析聚醚醚酮（PEEK）和钛网在颅脑损伤（TBI）后颅骨成形术中的临床疗效,并探讨PEEK材料的潜在优势。 方法选取解放军联勤保障部队第九〇一医院神经外科自2017年1月至2021年1月行颅骨成形术的48例TBI患者为研究对象,按照使用材料的不同将患者分为PEEK组（20例）和钛网组（28例）。比较2组患者手术出血、平均手术时间、住院时间、术后并发症、塑形效果及总治疗费用方面的差异。术后随访12个月,采用Karnofsky功能状态（KPS）评分评估患者的远期效果。 结果所有患者均于术后12~14 d拆除缝线,且切口为甲级愈合。2组患者手术出血、手术时间及住院时间比较,差异无统计学意义（P>0.05）。PEEK组术后总的并发症发生率（65.00%）与钛网组（60.71%）比较,差异无统计学意义（P>0.05）;2组术后颅内迟发性出血、术区硬膜下积液、术区颅内感染、癫痫及迟发性脑积水的发生率比较,差异无统计学意义（P>0.05）;钛网组患者的皮下积液发生率及治疗费用均低于PEEK组,差异具有统计学意义（P<0.05）。2组患者术后的平均满意度均较高,但PEEK组优于钛网组,差异具有统计学意义（P<0.05）。术后随访12个月,2组患者均未出现迟发性切口感染及材料外露,KPS评分比较差异无统计学意义（P>0.05）。 结论应用3D打印PEEK材料对TBI患者行颅骨成形术,总体并发症发生率与钛网材料相比无明显差异,但3D打印PEEK材料与颅骨契合更加完美,适合儿童、青少年及女性患者在经济情况好的条件下使用。     

3D打印技术在血管疾病诊治中的应用

正3D打印技术被制造业誉为第三次工业革命,在21世纪已经在许多领域都展现了巨大的价值和潜力,在医学领域如骨科、口腔科、整形外科、神经外科等都得到了广泛的应用。3D打印的开展应用也为血管疾病的诊治提供了新的方法,本文综述介绍3D打印技术在血管疾病诊治中的应用现状及未来发展趋势。1 3D打印技术的概念及种类3D打印技术(3DP)是一种快速成型技术,原理是将计算机辅助设计出的数字模型输入3D打印机中,通过逐     

3D打印在神经外科应用的新进展

3D打印自20世纪90年代迅速兴起并逐步应用于各行各业。近年来3D打印在医学领域的应用一定意义上带动了神经外科发展,其带来的变化或许将改变整个医疗行业面貌,其在未来还有多种应用可能。本文就3D打印在神经外科的应用作一综述。     

3D 打印技术在治疗颅内动脉瘤和动静脉畸形中的应用

3D打印是通过对原型实施数字建模,在计算机控制下完成对象物品的复制或创制过程。3D打印可完成个体化复制,实现对象物品外形和结构的精准模拟。利用多种医学影像学检查结果实施数据建模,3 D打印技术在生物医学领域的应用具有突出优势。近年来,3 D打印技术在脑血管病的预防、治疗和康复等方面均有应用。文章对3D打印技术在颅内动脉瘤和动静脉畸形中的应用进行了简要综述,并对未来应用前景进行了展望。     

人工智能及3D打印技术在心血管疾病诊疗中的应用进展

在大数据和开放科学时代,人工智能和3D打印技术蓬勃发展,其在心血管医学领域的探索应用突飞猛进.现代影像及检验技术积累了充分的原始数据,是人工智能探索的基础;心血管系统腔内结构复杂多变,充分利用人工智能和3D打印技术可以革新当前诊疗习惯和模式,提升服务效率和水平.现就人工智能和3D打印技术在心血管医学领域的应用进展做一综...     

3D打印技术在指导经导管二尖瓣介入手术中的应用与展望

二尖瓣疾病是危害人类心血管健康的常见瓣膜病之一。当前，已开发多种介入术式来治疗二尖瓣疾病。由于二尖瓣复合体特殊的解剖结构，导致介入手术难度增大，围术期并发症发生率居高不下。随着心血管3D打印技术的不断发展，3D可打印材料的更新和多学科协作相结合，3D打印成为经导管二尖瓣介入治疗中促进创新、提升手术成功率的技术。目前，患者特定的3D打印模型已用于经导管二尖瓣介入术前的器械尺寸调整、手术并发症的模拟预测等。通过运用二尖瓣介入模拟器模拟测试和多材料打印的创新方法，可以更好地预测器械将如何与患者特定的二尖瓣解剖结构相互作用。本文通过举例，阐述了3D打印在经导管二尖瓣介入治疗中的应用以及未来的发展方向。     

3D打印技术在骨科领域的应用

3D打印属于快速成型技术的一种,即以数字模型文件为基础,运用粉末状金属或塑料等可黏合材料通过逐层堆叠累积的方式制造三维实体的先进技术。近年来,随着该技术的不断发展,其已成为骨科领域的研究热点,并逐渐应用于临床中。本文综述了3D打印技术的发展历史与其在术前规划、术中导航、个性化假体和骨组织工程等骨科相关领域的相关应用,并结合其不足对其未来的发展做出技术展望。     

Influence of Layer Thickness and Raster Angle on the Mechanical Properties of 3D-Printed PEEK and a Comparative Mechanical Study between PEEK and ABS

Fused deposition modeling (FDM) is a rapidly growing 3D printing technology. However, printing materials are restricted to acrylonitrile butadiene styrene (ABS) or poly (lactic acid) (PLA) in most Fused deposition modeling (FDM) equipment. Here, we report on a new high-performance printing material, polyether-ether-ketone (PEEK), which could surmount these shortcomings. This paper is devoted to studying the influence of layer thickness and raster angle on the mechanical properties of 3D-printed PEEK. Samples with three different layer thicknesses (200, 300 and 400 μm) and raster angles (0°, 30° and 45°) were built using a polyether-ether-ketone (PEEK) 3D printing system and their tensile, compressive and bending strengths were tested. The optimal mechanical properties of polyether-ether-ketone (PEEK) samples were found at a layer thickness of 300 μm and a raster angle of 0°. To evaluate the printing performance of polyether-ether-ketone (PEEK) samples, a comparison was made between the mechanical properties of 3D-printed polyether-ether-ketone (PEEK) and acrylonitrile butadiene styrene (ABS) parts. The results suggest that the average tensile strengths of polyether-ether-ketone (PEEK) parts were 108% higher than those for acrylonitrile butadiene styrene (ABS), and compressive strengths were 114% and bending strengths were 115%. However, the modulus of elasticity for both materials was similar. These results indicate that the mechanical properties of 3D-printed polyether-ether-ketone (PEEK) are superior to 3D-printed ABS.     

Mechanical,Chemical, and Processing Properties of Specimens Manufactured from Poly-Ether-Ether-Ketone (PEEK) Using 3D Printing

As part of the experiments herein, the mechanical properties of specimens made of poly-ether-ether-ketone (PEEK) material using 3D printing technology were determined. Two populations of specimens were investigated, the first of which contained an amorphous structure, while the other held a crystal structure. The studies also investigated the influence of the print directionality on the mechanical properties obtained. Static tensile, three-point bending, and impact tests were carried out. The results for the effect of the structure type on the tensile properties showed that the modulus of elasticity was approximately 20% higher for the crystal than for the amorphous PEEK form. The Poisson’s ratios were similar, but the ratio was slightly higher for the amorphous samples than the crystalline ones. Furthermore, the studies included a chemical PEEK modification to increase the hydrophilicity. For this purpose, nitrite and hydroxyl groups were introduced into the chain by chemical reactions. The results demonstrate that the modified PEEK specimens had worse thermoplastic properties than the unmodified specimens.     

Nanosized Hydroxyapatite Coating on PEEK Implants Enhances Early Bone Formation: A Histological and Three-Dimensional Investigation in Rabbit Bone

Polyether ether ketone (PEEK) has been frequently used in spinal surgery with good clinical results. The material has a low elastic modulus and is radiolucent. However, in oral implantology PEEK has displayed inferior ability to osseointegrate compared to titanium materials. One idea to reinforce PEEK would be to coat it with hydroxyapatite (HA), a ceramic material of good biocompatibility. In the present study we analyzed HA-coated PEEK tibial implants via histology and radiography when following up at 3 and 12 weeks. Of the 48 implants, 24 were HA-coated PEEK screws (test) and another 24 implants served as uncoated PEEK controls. HA-coated PEEK implants were always osseointegrated. The total bone area (BA) was higher for test compared to control implants at 3 (p < 0.05) and 12 weeks (p < 0.05). Mean bone implant contact (BIC) percentage was significantly higher (p = 0.024) for the test compared to control implants at 3 weeks and higher without statistical significance at 12 weeks. The effect of HA-coating was concluded to be significant with respect to early bone formation, and HA-coated PEEK implants may represent a good material to serve as bone anchored clinical devices.     

Sustainable Surface Modification of Polyetheretherketone (PEEK) Implants by Hydroxyapatite/Silica Coating—An In Vivo Animal Study

Polyetheretherketone (PEEK) has the potential to overcome some of the disadvantages of titanium interbody implants in anterior cervical and discectomy and fusion (ACDF). However, PEEK shows an inferior biological behavior regarding osseointegration and bioactivity. Therefore, the aim of the study was to create a bioactive surface coating on PEEK implants with a unique nanopore structure enabling the generation of a long-lasting interfacial composite layer between coating material and implant. Seventy-two PEEK implants—each thirty-six pure PEEK implants (PI) and thirty-six PEEK implants with a sprayed coating consisting of nanocrystalline hydroxyapatite (ncHA) embedded in a silica matrix and interfacial composite layer (SPI)—were inserted in the femoral condyles of adult rats using a split-side model. After 2, 4 and 8 weeks, the femur bones were harvested. Half of the femur bones were used in histological and histomorphometrical analyses. Additionally, pull-out tests were performed in the second half. Postoperative healing was uneventful for all animals, and no postoperative complications were observed. Considerable crestal and medullary bone remodeling could be found around all implants, with faster bone formation around the SPI and fewer regions with fibrous tissue barriers between implant and bone. Histomorphometrical analyses showed a higher bone to implant contact (BIC) in SPI after 4 and 8 weeks (p < 0.05). Pull-out tests revealed higher pull-out forces in SPI at all time points (p < 0.01). The presented findings demonstrate that a combination of a bioactive coating and the permanent chemical and structural modified interfacial composite layer can improve bone formation at the implant surface by creating a sustainable bone-implant interface. This might be a promising way to overcome the bioinert surface property of PEEK-based implants.     

An Overview on the Rheology,Mechanical Properties,Durability, 3D Printing,and Microstructural Performance of Nanomaterials in Cementitious Composites

The most active research area is nanotechnology in cementitious composites, which has a wide range of applications and has achieved popularity over the last three decades. Nanoparticles (NPs) have emerged as possible materials to be used in the field of civil engineering. Previous research has concentrated on evaluating the effect of different NPs in cementitious materials to alter material characteristics. In order to provide a broad understanding of how nanomaterials (NMs) can be used, this paper critically evaluates previous research on the influence of rheology, mechanical properties, durability, 3D printing, and microstructural performance on cementitious materials. The flow properties of fresh cementitious composites can be measured using rheology and slump. Mechanical properties such as compressive, flexural, and split tensile strength reveal hardened properties. The necessary tests for determining a NM’s durability in concrete are shrinkage, pore structure and porosity, and permeability. The advent of modern 3D printing technologies is suitable for structural printing, such as contour crafting and binder jetting. Three-dimensional (3D) printing has opened up new avenues for the building and construction industry to become more digital. Regardless of the material science, a range of problems must be tackled, including developing smart cementitious composites suitable for 3D structural printing. According to the scanning electron microscopy results, the addition of NMs to cementitious materials results in a denser and improved microstructure with more hydration products. This paper provides valuable information and details about the rheology, mechanical properties, durability, 3D printing, and microstructural performance of cementitious materials with NMs and encourages further research.     

Influence of Infill Pattern on the Elastic Mechanical Properties of Fused Filament Fabrication (FFF) Parts through Experimental Tests and Numerical Analyses

Fused Filament Fabrication (FFF) is one of the most extensive additive manufacturing technologies for printing prototypes or final parts in various fields. Some printed parts need to meet structural requirements to be functional parts. Therefore, it is necessary to know the mechanical behavior of the printed samples as a function of the printing parameters in order to optimize the material used during the manufacturing process. It is known that FFF parts can present orthotropic characteristics as a consequence of the manufacturing process, in which the material is deposited layer by layer. Therefore, these characteristics must be considered for a correct evaluation of the printed parts from a structural point of view. In this paper, the influence of the type of filling pattern on the main mechanical properties of the printed parts is analyzed. For this purpose, the first parts are 3D printed using three different infill patterns, namely grid, linear with a raster orientation of 0 and 90°, and linear with a raster orientation of 45°. Then, experimental tensile tests, on the one hand, and numerical analyses using finite elements, on the other hand, are carried out. The elastic constants of the material are obtained from the experimental tests. From the finite element analysis, using a simple approach to create a Representative Volume Model (RVE), the constitutive characteristics of the material are estimated: Young’s Moduli and Poisson’s ratios of the printed FFF parts. These values are successfully compared with those of the experimental tests. The results clearly show differences in the mechanical properties of the FFF printed parts, depending on the internal arrangement of the infill pattern, even if similar 3D printing parameters are used.     

Sustainable Additive Manufacturing: Mechanical Response of Polyethylene Terephthalate Glycol over Multiple Recycling Processes

The continuous demand for thermoplastic polymers in a great variety of applications, combined with an urgent need to minimize the quantity of waste for a balanced energy-from-waste strategy, has led to increasing scientific interest in developing new recycling processes for plastic products. Glycol-modified polyethylene terephthalate (PETG) is known to have some enhanced properties as compared to polyethylene terephthalate (PET) homopolymer; this has recently attracted the interest from the fused filament fabrication (FFF) three-dimensional (3D) printing community. PET has shown a reduced ability for repeated recycling through traditional processes. Herein, we demonstrate the potential for using recycled PETG in consecutive 3D printing manufacturing processes. Distributed recycling additive manufacturing (DRAM)-oriented equipment was chosen in order to test the mechanical and thermal response of PETG material in continuous recycling processes. Tensile, flexure, impact strength, and Vickers micro-hardness tests were carried out for six (6) cycles of recycling. Finally, Raman spectroscopy as well as thermal and morphological analyses via scanning electron microscopy (SEM) fractography were carried out. In general, the results revealed a minor knockdown effect on the mechanical properties as well as the thermal properties of PETG following the process proposed herein, even after six rounds of recycling.     

Sustainable Additive Manufacturing: Mechanical Response of Polyamide 12 over Multiple Recycling Processes

Plastic waste reduction and recycling through circular use has been critical nowadays, since there is an increasing demand for the production of plastic components based on different polymeric matrices in various applications. The most commonly used recycling procedure, especially for thermoplastic materials, is based on thermomechanical process protocols that could significantly alter the polymers’ macromolecular structure and physicochemical properties. The study at hand focuses on recycling of polyamide 12 (PA12) filament, through extrusion melting over multiple recycling courses, giving insight for its effect on the mechanical and thermal properties of Fused Filament Fabrication (FFF) manufactured specimens throughout the recycling courses. Three-dimensional (3D) FFF printed specimens were produced from virgin as well as recycled PA12 filament, while they have been experimentally tested further for their tensile, flexural, impact and micro-hardness mechanical properties. A thorough thermal and morphological analysis was also performed on all the 3D printed samples. The results of this study demonstrate that PA12 can be successfully recycled for a certain number of courses and could be utilized in 3D printing, while exhibiting improved mechanical properties when compared to virgin material for a certain number of recycling repetitions. From this work, it can be deduced that PA12 can be a viable option for circular use and 3D printing, offering an overall positive impact on recycling, while realizing 3D printed components using recycled filaments with enhanced mechanical and thermal stability.     

3D PEEK Objects Fabricated by Fused Filament Fabrication (FFF)

PEEK (poly ether ether ketone) materials printed using FFF 3D printing have been actively studied on applying electronic devices in satellites owing to their excellent light weight and thermal resistance. However, the PEEK FFF process generated cavities inside due to large shrinkage has degraded both mechanical integrity and printing reliability. Here, we have investigated the correlations between nozzle temperatures and PEEK printing behaviors such as the reliability of printed line width and surface roughness. As the temperature increased from 360 to 380 °C, the width of the printed line showed a tendency to decrease. However, the width of PEEK printed lines re-increased from 350 to 426 μm at the nozzle temperatures between 380 and 400 °C, associated with solid to liquid-like phase transition and printed out distorted and disconnected lines. The surface roughness of PEEK objects increased from 49 to 55 μm as the nozzle temperature increased from 380 to 400 °C, where PEEK is melted down and quickly solidified based on more energy and additional heating time at higher printing temperatures at 400 °C. Based on these printing trends, a reliability analysis of the printed line was performed. The printed line formed the most uniform width at 380 °C and had a highest Weibull coefficient of 28.6 using the reliability analysis technique called Weibull modulus.