3D Printing Hip Prostheses Offer Accurate Reconstruction,Stable Fixation,and Functional Recovery for Revision Total Hip Arthroplasty with Complex Acetabular Bone Defect

Complicated and large acetabular bone defects present the main challenges and difficulty in the revision of total hip arthroplasty(THA).This study aimed to explore the advantages of three-dimensional(3D)printing technology in the reconstruction of such acetabular bone defects.We retrospectively analyzed the prognosis of four severe bone defects around the acetabulum in three patients who were treated using 3D printing technology.Reconstruction of bone defect by conventional methods was difficult in these patients.In this endeavor,we used radiographic methods,related computer software such as Materialise's interactive medical image control system and Siemens NX software,and actual surgical experience to estimate defect volume,prosthesis stability,and installation accuracy,respectively.Moreover,a Harris hip score was obtained to evaluate limb function.It was found that bone defects could be adequately reconstructed using a 3D printing prosthesis,and its stability was reliable.The Harris hip score indicated a very good functional recovery in all three patients.In conclusion,3D printing technology had a good therapeutic effect on both complex and large bone defects in the revision of THA.It was able to achieve good curative effects in patients with large bone defects.

3D printing of personalized polylactic acid scaffold laden with GelMA/autologous auricle cartilage to promote ear reconstruction

At present,the clinical reconstruction of the auricle usually adopts the strategy of taking autologous costal cartilage.This method has great trauma to patients,poor plasticity and inaccurate shaping.Three-dimensional(3D)printing technology has made a great breakthrough in the clinical application of orthopedic implants.This study explored the combination of 3D printing and tissue engineering to precisely reconstruct the auricle.First,a polylactic acid(PLA)polymer scaffold with a precisely customized patient appearance was fabricated,and then auricle cartilage fragments were loaded into the 3D-printed porous PLA scaffold to promote auricle reconstruction.In vitro,gelatin methacrylamide(GelMA)hydrogels loaded with different sizes of rabbit ear cartilage fragments were studied to assess the regenerative activity of various autologous cartilage fragments.In vivo,rat ear cartilage fragments were placed in an accurately designed porous PLA polymer ear scaffold to promote auricle reconstruction.The results indicated that the chondrocytes in the cartilage fragments could maintain the morphological phenotype in vitro.After three months of implantation observation,it was conducive to promoting the subsequent regeneration of cartilage in vivo.The autologous cartilage fragments combined with 3D printing technology show promising potential in auricle reconstruction.

3D printing of calcium phosphate bioceramic with tailored biodegradation rate for skull bone tissue reconstruction

The bone regenerative scaffold with the tailored degradation rate matching with the growth rate of the new bone is essential for adolescent bone repair.To satisfy these requirement,we proposed bone tissue scaffolds with controlled degradation rate using osteoinductive materials(Ca-P bioceramics),which is expected to present a controllable biodegradation rate for patients who need bone regeneration.Physicochemical properties,porosity,compressive strength and degradation properties of the scaffolds were studied.3D printed Ca-P scaffold(3DS),gas foaming Ca-P scaffold(FS)and autogenous bone(AB)were used in vivo for personalized beagle skull defect repair.Histological results indicated that the 3DS was highly vascularized and well combined with surrounding tissues.FS showed obvious newly formed bone tissues.AB showed the best repair effect,but it was found that AB scaffolds were partially absorbed and degraded.This study indicated that the 3D printed Ca-P bioceramics with tailored biodegradation rate is a promising candidate for personalized skull bone tissue reconstruction.

Vertebrae CT Images 3D Reconstruction with Improve Marching Cubes Algorithm

Medical images 3D reconstruction is an important part in medical image analysis and processing. Although lots of algorithms have been proposed continuously, speed and accuracy cannot conform to actual needs, which has always been the focus topic. In this paper, we propose an Improved Marching Cubes algorithm ( I-MC) based on the surface rendering theory, which implements 3D reconstruction of the vertebrae. Firstly, we preprocessed the original 2D vertebrae CT images with the bilateral-filter denoising algorithm. Secondly, on the basis of the traditional Marching Cubes algorithm, the seed voxels were extracted and the Region Growing algorithm was used to determine all voxels that contain isosurfaces. Then, the Golden Section instead of the traditional linear interpolation was used to calculate the equivalent point, and this method reduced the calculations of public edges. VTK and OpenGL implemented 3D reconstruction of the vertebrae on GPU quickly and accurately. The experimental results show that when compared with the traditional Marching Cubes algorithm and Mesh Simplification Marching Cubes algorithm, the improved algorithm achieves a significant improvement of reconstruction speed while preserving the accurate results. The efficiency of algorithm is improved dramatically. This method is real-time and achieves the goal of efficient 3D reconstruction of vertebrae CT images.

Radiotherapy-customized head immobilization masks:from modeling and analysis to 3D printing

Immobilization devices may be a valuable aid to ensure the improved effectiveness of radiotherapy treatments where constraining the movements of specific anatomical segments is crucial. This need is also present in other situations, specifically when the superposition of various medical images is required for fine identification and characterization of some pathologies. Because of their structural characteristics, existing head immobilization systems may be claustrophobic and very uncomfortable for patients, during both the modeling and usage stages. Because of this, it is important to minimize all the discomforts related to the mask to alleviate patients’ distress and to simultaneously guarantee and maximize the restraint effectiveness of the mask. In the present work, various head immobilization mask models are proposed based on geometrical information extracted from computerized tomography images and from 3D laser scanning point clouds. These models also consider the corresponding connection to a radiotherapy table, as this connection is easily altered to accommodate various manufacturers’ solutions. A set of materials used in the radiotherapy field is considered to allow the assessment of the stiffness and strength of the masks when submitted to typical loadings.

Sparse-view neutron CT 3D image reconstruction algorithm based on split Bregman method

As a complement to X-ray computed tomography(CT),neutron tomography has been extensively used in nuclear engineer-ing,materials science,cultural heritage,and industrial applications.Reconstruction of the attenuation matrix for neutron tomography with a traditional analytical algorithm requires hundreds of projection views in the range of 0°to 180°and typically takes several hours to complete.Such a low time-resolved resolution degrades the quality of neutron imaging.Decreasing the number of projection acquisitions is an important approach to improve the time resolution of images;however,this requires efficient reconstruction algorithms.Therefore,sparse-view reconstruction algorithms in neutron tomography need to be investigated.In this study,we investigated the three-dimensional reconstruction algorithm for sparse-view neu-tron CT scans.To enhance the reconstructed image quality of neutron CT,we propose an algorithm that uses OS-SART to reconstruct images and a split Bregman to solve for the total variation(SBTV).A comparative analysis of the performances of each reconstruction algorithm was performed using simulated and actual experimental data.According to the analyzed results,OS-SART-SBTV is superior to the other algorithms in terms of denoising,suppressing artifacts,and preserving detailed structural information of images.

Technique Note for Staged Resection of Giant Invasive High-Cervical Schwannoma and Reconstruction of C2—C4 with 3D Printing Technique

A schwannoma is a relatively common benign spinal cord tumour;however,giant schwannomas with extensive cervical vertebral erosion are rare,and the treatment strategy,especially the reconstruction of the upper cervical vertebra,remains a challenge for spine surgeons.Here,we present a rare case of giant invasive high-cervical schwannoma with extensive erosion of the C2—C4 vertebral bodies and tumour-encased left vertebral artery.The surgical strategy and the reconstruction of C2—C4 with 3D printing techniques were discussed and performed.A 32-year-old man presented to our department with complaints of gait disturbance and weakness in both upper and lower extremities.His limb muscle strength was grade 2 or 3/5,and he exhibited severe bladder and bowel dysfunction on admission.X-ray and computed tomography of the cervical spine showed an extremely large erosive lesion at the C2—C4 vertebral bodies and lateral masses.Magnetic resonance imaging of the cervical spine showed a large soft-tissue mass on the left aspect of the C2—C5 vertebra and in the spinal canal at the C3—C4 level.A staged schwannoma resection,instrumented fixation,and reconstruction of C2—C4 with 3D metal printing technique were performed.The patient achieved good postoperative outcomes and returned to normal daily life with no recurrence of schwannoma during follow-up for four and a half years.The 3D-printed implant achieved solid fusion with the remaining cervical spine.We performed staged resection of the giant invasive high-cervical schwannoma and reconstructed the erosive C2—C4 vertebra with the assistance of a 3D printing technique.3D printing technology has facilitated the design and manufacture of customised implants for complex surgical procedures.

Improvement of Binocular Reconstruction Algorithm for Measuring 3D Pavement Texture Using a Single Laser Line Scanning Constraint

The dense and accurate measurement of 3D texture is helpful in evaluating the pavement function.To form dense mandatory constraints and improve matching accuracy,the traditional binocular reconstruction technology was improved threefold.First,a single moving laser line was introduced to carry out global scanning constraints on the target,which would well overcome the difficulty of installing and recognizing excessive laser lines.Second,four kinds of improved algorithms,namely,disparity replacement,superposition synthesis,subregion segmentation,and subregion segmentation centroid enhancement,were established based on different constraint mechanism.Last,the improved binocular reconstruction test device was developed to realize the dual functions of 3D texture measurement and precision self-evaluation.Results show that compared with traditional algorithms,the introduction of a single laser line scanning constraint is helpful in improving the measurement’s accuracy.Among various improved algorithms,the improvement effect of the subregion segmentation centroid enhancement method is the best.It has a good effect on both overall measurement and single pointmeasurement,which can be considered to be used in pavement function evaluation.

Advancing Wound Filling Extraction on 3D Faces:An Auto-Segmentation and Wound Face Regeneration Approach

Facial wound segmentation plays a crucial role in preoperative planning and optimizing patient outcomes in various medical applications.In this paper,we propose an efficient approach for automating 3D facial wound segmentation using a two-stream graph convolutional network.Our method leverages the Cir3D-FaIR dataset and addresses the challenge of data imbalance through extensive experimentation with different loss functions.To achieve accurate segmentation,we conducted thorough experiments and selected a high-performing model from the trainedmodels.The selectedmodel demonstrates exceptional segmentation performance for complex 3D facial wounds.Furthermore,based on the segmentation model,we propose an improved approach for extracting 3D facial wound fillers and compare it to the results of the previous study.Our method achieved a remarkable accuracy of 0.9999993% on the test suite,surpassing the performance of the previous method.From this result,we use 3D printing technology to illustrate the shape of the wound filling.The outcomes of this study have significant implications for physicians involved in preoperative planning and intervention design.By automating facial wound segmentation and improving the accuracy ofwound-filling extraction,our approach can assist in carefully assessing and optimizing interventions,leading to enhanced patient outcomes.Additionally,it contributes to advancing facial reconstruction techniques by utilizing machine learning and 3D bioprinting for printing skin tissue implants.Our source code is available at https://github.com/SIMOGroup/WoundFilling3D.

3D printing of interferonγ-preconditioned NSC-derived exosomes/collagen/chitosan biological scaffolds for neurological recovery after TBI

The reconstruction of neural function and recovery of chronic damage following traumatic brain injury(TBI)remain significant clinical challenges.Exosomes derived from neural stem cells(NSCs)offer various benefits inTBI treatment.Numerous studies confirmed that appropriate preconditioning methods enhanced the targetedefficacy of exosome therapy.Interferon-gamma(IFN-γ)possesses immunomodulatory capabilities and is widelyinvolved in neurological disorders.In this study,IFN-γwas employed for preconditioning NSCs to enhance theefficacy of exosome(IFN-Exo,IE)for TBI.miRNA sequencing revealed the potential of IFN-Exo in promotingneural differentiation and modulating inflammatory responses.Through low-temperature 3D printing,IFN-Exowas combined with collagen/chitosan(3D-CC-IE)to preserve the biological activity of the exosome.The deliveryof exosomes via biomaterial scaffolds benefited the retention and therapeutic potential of exosomes,ensuring that they could exert long-term effects at the injury site.The 3D-CC-IE scaffold exhibited excellentbiocompatibility and mechanical properties.Subsequently,3D-CC-IE scaffold significantly improved impairedmotor and cognitive functions after TBI in rat.Histological results showed that 3D-CC-IE scaffold markedlyfacilitated the reconstruction of damaged neural tissue and promoted endogenous neurogenesis.Furthermechanistic validation suggested that IFN-Exo alleviated neuroinflammation by modulating the MAPK/mTORsignaling pathway.In summary,the results of this study indicated that 3D-CC-IE scaffold engaged in long-termpathophysiological processes,fostering neural function recovery after TBI,offering a promising regenerativetherapy avenue.

Acoustical properties of a 3D printed honeycomb structure filled with nanofillers:Experimental analysis and optimization for emerging applications

The novelty of this research lies in the successful fabrication of a 3D-printed honeycomb structure filled with nanofillers for acoustic properties,utilizing an impedance tube setup in accordance with ASTM standard E 1050-12.The Creality Ender-3,a 3D printer,was used for printing the honeycomb structures,and polylactic acid(PLA)material was employed for their construction.The organic,inorganic,and polymeric compounds within the composites were identified using fourier transformation infrared(FTIR)spectroscopy.The structure and homogeneity of the samples were examined using a field emission scanning electron microscope(FESEM).To determine the sound absorption coefficient of the 3D printed honeycomb structure,numerous samples were systematically developed using central composite design(CCD)and analysed using response surface methodology(RSM).The RSM mathematical model was established to predict the optimum values of each factor and noise reduction coefficient(NRC).The optimum values for an NRC of 0.377 were found to be 1.116 wt% carbon black,1.025 wt% aluminium powder,and 3.151 mm distance between parallel edges.Overall,the results demonstrate that a 3Dprinted honeycomb structure filled with nanofillers is an excellent material that can be utilized in various fields,including defence and aviation,where lightweight and acoustic properties are of great importance.

A Systematic Approach for Making 3D-Printed Patient-Specific Implants for Craniomaxillofacial Reconstruction

Craniomaxillofacial reconstruction implants,which are extensively used in head and neck surgery,are conventionally made in standardized forms.During surgery,the implant must be bended manually to match the anatomy of the individual bones.The bending process is time-consuming,especially for inexperienced surgeons.Moreover,repetitive bending may induce undesirable internal stress concentration,resulting in fatigue under masticatory loading in v iv o and causing various complications such as implant fracture,screw loosening,and bone resorption.There have been reports on the use of patient-specific 3D-printed implants for craniomaxillofacial reconstruction,although few reports have considered implant quality.In this paper,we present a systematic approach for making 3D-printed patientspecific surgical implants for craniomaxillofacial reconstruction.The approach consists of three parts:First,an easy-to-use design module is developed using Solidworks®software,which helps surgeons to design the implants and the axillary fixtures for surgery.Design engineers can then carry out the detailed design and use finite-element modeling(FEM)to optimize the design.Second,the fabrication process is carried out in three steps:0 testing the quality of the powder;(2)setting up the appropriate process parameters and running the 3D printing process;and (3)conducting post-processing treatments(i.e.,heat and surface treatments)to ensure the quality and performance of the implant.Third,the operation begins after the final checking of the implant and sterilization.After the surgery,postoperative rehabilitation follow-up can be carried out using our patient tracking software.Following this systematic approach,we have successfully conducted a total of 41 surgical cases.3D-printed patient-specific implants have a number of advantages;in particular,their use reduces surgery time and shortens patient recovery time.Moreover,the presented approach helps to ensure implant quality.

CT guidance ^(125)I seed implantation for pelvic recurrent rectal cancer assisted by 3D printing individual non-coplanar template

Objective To analyze the difference of dosimetric parameters between pre-plan and post-plan of 125I radioactive seed implantation assisted by 3D printing individual non-coplanar template（3D printing template）for locally recurrent rectal cancer（LRRC）.Methods From February 2016 to April 2016,a total of 10 patients with locally recurrent rectal cancer received 125I seeds implan-

3D printing of patient-specific neck splints for the treatment of post-burn neck contractures

Dear Editor,Burn scar contracture is a common problem in healing burn wounds of the neck. It can cause both pain and dysfunction if not treated adequately (1)The treatment of such wounds often involves a combination of surgery and splinting therapy (2)A variety of splints, including the thermoplastic static neck splint [3], the Watusi collar [4], manually fabricated splints, and pre-fabricated splints such as the Philadelphia collar have been used for the management of scar contractures. However, each type of splint has its own advantages and disadvantages, and none of these splints seem to reduce the need for skin reconstruction nor delays the time until surgical re-construction [5].

Analysis of the microstructure of microbial solidified sand and engineering residue based on CT scanning

A close relationship exists between the pore network structure of microbial solidified soil and its macroscopic mechanical properties.The microbial solidified engineering residue and sand were scanned by computed tomography(CT),and a three-dimensional model of the sample was established by digital image processing.A spatial pore network ball-stick model of the representative elementary volume(REV)was established,and the REV parameters of the sample were calculated.The pore radius,throat radius,pore coordination number,and throat length were normally distributed.The soil particle size was larger after solidification.The calcium carbonate content of the microbial solidified engineering residue’s consolidated layer decreased with the soil depth,the porosity increased,the pore and throat network developed,and the ultimate structure was relatively stable.The calcium carbonate content of the microbial solidified sand’s consolidated layer decreased and increased with the soil depth.The content reached the maximum,the hardness of the consolidated layer was the highest,and the development of the pore and throat network was optimum at a depth of 10–15 mm.

3D打印非共面模板CT引导下^(125)Ⅰ粒子植入治疗恶性肿瘤临床应用

目的探讨3D打印非共面模板CT引导下放射性粒子植入治疗对于肿瘤治疗的安全性和有效性。方法20例恶性肿瘤患者,在接受3D打印非共面模板联合CT引导下放射性粒子植入治疗后进行回顾性研究。粒子植入流程包据术前CT定位及计划设计、术中方案优化、共面模板辅助CT引导下穿刺、粒子植入、术后3天计划验证、术后1~3个月疗效评价。疗效评价采用实体瘤评价标准(RECIST)v1.1,不良反应评价采用不良事件常用术语评定标准(CTCAE)v3.0。观察肿瘤区(gross tumor volume,GTV)接受90~120 Gy处方剂量的近期疗效和安全性。结果所有患者经过3D打印非共面模板联合CT引导下放射性粒子植入治疗后临床症状均有改善,1个月后部分缓解(PR)8例(40%),3个月后完全缓解+部分缓解(CR+PR)18例(90%),5例CR,13例PR,粒子植入后局部病灶均无进展,无严重并发症。结论3D打印非共面模板联合术中CT引导下永久性^(125)Ⅰ粒子组织间植入治疗术前术后计划可获得良好的一致性,有良好的治疗准确性,具有并发症少,简便安全等优点,为规范临床操作流程及精确植入的提供了新的方法。

CT三维重建配合3D打印技术在辅助寰枢椎椎弓根螺钉置入的应用价值评估

目的:探讨CT三维重建配合3D打印技术在辅助寰枢椎椎弓根螺钉置入的应用价值。方法:通过CT三维重建的多种后处理技术明确寰枢椎病变13例作为观察组,再将CT三维重建、逆向工程原理及快速成形技术相结合,设计出一种新型的导航模板,辅助椎弓根螺钉置入,并与13例之前已通过X线透视置钉法的病例(对照组)进行置钉效果比较。结果:对照组13例共置椎弓根螺钉41枚,其中Ⅰ类置钉9枚,Ⅱ类置钉18枚,Ⅲ类置钉14枚,成功率65.9%;观察组共打印颈椎模型13例,设计导向模板21个,5例由于先前通过X线透视仅在枢椎两侧的椎弓根内置钉,只制作出枢椎的导航模板;模拟手术同样置钉41枚,其中Ⅰ类置钉15枚,Ⅱ类置钉21枚,Ⅲ类置钉5枚,成功率87.8%。结论:CT三维重建的各种后处理技术不仅能够准确的判断寰枢椎病变,并能配合3D打印技术,制作出个体化的导航模板,使上颈椎椎弓根螺钉的置入变得既安全又省时,并能在术后准确评估置钉效果。

Design and Application of 3D Printing Based Personalised Pelvic Prostheses

In this paper,we describe the design and surgical process of personalised pelvic prostheses fixation through 3D printing according to different Enneking pelvic tumour zones:the ilium(Zone I),acetabulum(Zone II),and pubis and ischium(Zone III).A 3D model of the pelvis was reconstructed using imaging data,and the parameters on the planes of the acetabulum and pelvic incisal margin were measured.The main body of the pelvic prosthesis was constructed,a porous structure was designed on the bone-prosthesis interface,and the movement paths,lengths,and diameters of screws were planned.By combining the pathological model and osteotomy guide,limb salvage reconstruction was performed in patients with pelvic tumours.Preoperative and postoperative data were compared to verify the prosthesis stability.Our investigation revealed that the long-term survival of pelvic reconstruction prostheses depends on accurate matching with the bone defect area,good initial stability,and a porous structure to allow bone ingrowth.

双源64排螺旋CT分期增强扫描及3D后处理对肝血管瘤的诊断价值

目的评价双源64排螺旋CT三期增强扫描及3D后处理功能对肝脏血管瘤容积测定的诊断价值。方法回顾性的分析经临床手术病理证实的60例肝血管瘤的CT资料。测定60例肝脏血管瘤患者不同时相的CT值,并采用3D软件测定不同时相的强化容积。结果 60例病例中,平扫有79个病灶(91.86%)为低密度灶,7个病灶为等或高密度;动脉期72个病灶边缘点状、斑片状强化,14个未出现强化;门脉期及延迟期相继出现强化,最终都强化至等密度。3D后处理后,可从不同角度不同时相肿瘤的强化容积改变看到不同的瘤体整体形态学改变及肿瘤与肝动脉之间的关系。结论双源64排螺旋CT三期增强扫描及3D后处理可清楚显示肝血管瘤的典型CT表现,对血管瘤的诊断及鉴别诊断有很大价值。

Characterization of 3D pore nanostructure and stress-dependent permeability of organic-rich shales in northern Guizhou Depression,China

The three-dimensional(3D)pore structures and permeability of shale are critical for forecasting gas production capacity and guiding pressure differential control in practical reservoir extraction.However,few investigations have analyzed the effects of microscopic organic matter(OM)morphology and 3D pore nanostructures on the stress sensitivity,which are precisely the most unique and controlling factors of reservoir quality in shales.In this study,ultra-high nanoscale-resolution imaging experiments,i.e.focused ion beam-scanning electron microscopy(FIB-SEMs),were conducted on two organic-rich shale samples from Longmaxi and Wufeng Formations in northern Guizhou Depression,China.Pore morphology,porosity of 3D pore nanostructures,pore size distribution,and connectivity of the six selected regions of interest(including clump-shaped OMs,interstitial OMs,framboidal pyrite,and microfractures)were qualitatively and quantitatively characterized.Pulse decay permeability(PDP)measurement was used to investigate the variation patterns of stress-dependent permeability and stress sensitivity of shales under different confining pressures and pore pressures,and the results were then used to calculate the Biot coefficients for the two shale formations.The results showed that the samples have high OM porosity and 85%of the OM pores have the radius of less than 40 nm.The OM morphology and pore structure characteristics of the Longmaxi and Wufeng Formations were distinctly different.In particular,the OM in the Wufeng Formation samples developed some OM pores with radius larger than500 nm,which significantly improved the connectivity.The macroscopic permeability strongly depends on the permeability of OM pores.The stress sensitivity of permeability of Wufeng Formation was significantly lower than that of Longmaxi Formation,due to the differences in OM morphology and pore structures.The Biot coefficients of 0.729 and 0.697 were obtained for the Longmaxi and Wufeng Formations,respectively.