A Novel Computer-Aided Approach for Parametric Investigation of Custom Design of Fracture Fixation Plates

The present study proposes an integrated computer-aided approach combining femur surface modeling, fracture evidence recover plate creation, and plate modification in order to conduct a parametric investigation of the design of custom plate for a specific patient. The study allows for improving the design efficiency of specific plates on the patients’ femur parameters and the fracture information. Furthermore, the present approach will lead to exploration of plate modification and optimization. The three-dimensional (3D) surface model of a detailed femur and the corresponding fixation plate were represented with high-level feature parameters, and the shape of the specific plate was recursively modified in order to obtain the optimal plate for a specific patient. The proposed approach was tested and verified on a case study, and it could be helpful for orthopedic surgeons to design and modify the plate in order to fit the specific femur anatomy and the fracture information

Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): Guidelines for medical 3D printing and appropriateness for clinical scenarios

Este número da revista Cadernos de Estudos Sociais estava em organização quando fomos colhidos pela morte do sociólogo Ernesto Laclau. Seu falecimento em 13 de abril de 2014 surpreendeu a todos, e particularmente ao editor Joanildo Burity, que foi seu orientando de doutorado na University of Essex, Inglaterra, e que recentemente o trouxe à Fundação Joaquim Nabuco para uma palestra, permitindo que muitos pudessem dialogar com um dos grandes intelectuais latinoamericanos contemporâneos. Assim, buscamos fazer uma homenagem ao sociólogo argentino publicando uma entrevista inédita concedida durante a sua passagem pelo Recife, em 2013, encerrando essa revista com uma sessão especial sobre a sua trajetória

In Silico Optimization of Femoral Fixator Position and Configuration by Parametric CAD Model

Structural analysis, based on the finite element method, and structural optimization, can help surgery planning or decrease the probability of fixator failure during bone healing. Structural optimization implies the creation of many finite element model instances, usually built using a computer-aided design (CAD) model of the bone-fixator assembly. The three most important features of such CAD models are: parameterization, robustness and bidirectional associativity with finite elements (FE) models. Their significance increases with the increase in the complexity of the modeled fixator. The aim of this study was to define an automated procedure for the configuration and placement of fixators used in the treatment of long bone fractures. Automated and robust positioning of the selfdynamisable internal fixator on the femur was achieved and sensitivity analysis of fixator stress on the change of major design parameters was performed. The application of the proposed methodology is considered to be beneficial in the preparation of CAD models for automated structural optimization procedures used in long bone fixation

Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): guidelines for medical 3D printing and appropriateness for clinical scenarios

Abstract Medical three-dimensional (3D) printing has expanded dramatically over the past three decades with growth in both facility adoption and the variety of medical applications. Consideration for each step required to create accurate 3D printed models from medical imaging data impacts patient care and management. In this paper, a writing group representing the Radiological Society of North America Special Interest Group on 3D Printing (SIG) provides recommendations that have been vetted and voted on by the SIG active membership. This body of work includes appropriate clinical use of anatomic models 3D printed for diagnostic use in the care of patients with specific medical conditions. The recommendations provide guidance for approaches and tools in medical 3D printing, from image acquisition, segmentation of the desired anatomy intended for 3D printing, creation of a 3D-printable model, and post-processing of 3D printed anatomic models for patient care.https://deepblue.lib.umich.edu/bitstream/2027.42/146524/1/41205_2018_Article_30.pd

Unveiling the prospects of point-of-care 3D printing of Polyetheretherketone (PEEK) patient-specific implants

Additive manufacturing (AM) or three-dimensional (3D) printing is rapidly gaining acceptance in the healthcare sector. With the availability of low-cost desktop 3D printers and inexpensive materials, in-hospital or point-of-care (POC) manufacturing has gained considerable attention in personalized medicine. Material extrusion-based [Fused Filament Fabrication (FFF)] 3D printing of low-temperature thermoplastic polymer is the most commonly used 3D printing technology in hospitals due to its ease of operability and availability of low-cost machines. However, this technology has been limited to the production of anatomical biomodels, surgical guides, and prosthetic aids and has not yet been adopted into the mainstream production of patient-specific or customized implants. Polyetheretherketone (PEEK), a high-performance thermoplastic polymer, has been used mainly in reconstructive surgeries as a reliable alternative to other alloplastic materials to fabricate customized implants. With advancements in AM systems, prospects for customized 3D printed surgical implants have emerged, increasing attention for POC manufacturing. A customized implant may be manufactured within few hours using 3D printing, allowing hospitals to become manufacturers. However, manufacturing customized implants in a hospital environment is challenging due to the number of actions necessary to design and fabricate the implants. The focus of this thesis relies on material extrusion-based 3D printing of PEEK patient-specific implants (PSIs). The ambitious challenge was to bridge the performance gap between 3D printing of PEEK PSIs for reconstructive surgery and the clinical applicability at the POC by taking advantage of recent developments in AM systems. The main reached milestones of this project include: (i) assessment of the fabrication feasibility of PEEK surgical implants using material extrusion-based 3D printing technology, (ii) incorporation of a digital clinical workflow for POC manufacturing, (iii) assessment of the clinical applicability of the POC manufactured patient-specific PEEK scaphoid prosthesis, (iv) visualization and quantification of the clinical reliability of the POC manufactured patient-specific PEEK cranial implants, and (v) assessment of the clinical performance of the POC manufactured porous patient-specific PEEK orbital implants. During this research work, under the first study, we could demonstrate the prospects of FFF 3D printing technology for POC PEEK implant manufacturing. It was established that FFF 3D printing of PEEK allows the construction of complex anatomical geometries which cannot be manufactured using other technologies. With a clinical digital workflow implementation at the POC, we could further illustrate a smoother integration and faster implant production (within two hours) potential for a complex-shaped, patented PEEK patient-specific scaphoid prosthesis. Our results revealed some key challenges during the FFF printing process, exploring the applicability of POC manufactured FFF 3D printed PEEK customized implants in craniofacial reconstructions. It was demonstrated that optimal heat distribution around the cranial implants and heat management during the printing process are essential parameters that affect crystallinity, and thus the quality of the FFF 3D printed PEEK cranial implants. At this stage of the investigation, it was observed that the root mean square (RMS) values for dimensional accuracy revealed higher deviations in large-sized cranial prostheses with “horizontal lines” characteristics. Further optimization of the 3D printer, a layer-by-layer increment in the airflow temperature was done, which improved the performance of the FFF PEEK printing process for large-sized cranial implants. We then evaluated the potential clinical reliability of the POC manufactured 3D printed PEEK PSIs for cranial reconstruction by quantitative assessment of geometric, morphological, and biomechanical characteristics. It was noticed that the 3D printed customized cranial implants had high dimensional accuracy and repeatability, displaying clinically acceptable morphologic similarity concerning fit and contours continuity. However, the tested cranial implants had variable peak load values with discrete fracture patterns from a biomechanical standpoint. The implants with the highest peak load had a strong bonding with uniform PEEK fusion and interlayer connectivity, while air gaps and infill fusion lines were observed in implants with the lowest strength. The results of this preclinical study were in line with the clinical applicability of cranial implants; however, the biomechanical attribute can be further improved. It was noticed that each patient-specific reconstructive implant required a different set of manufacturing parameters. This was ascertained by manufacturing a porous PEEK patient-specific orbital implant. We evaluated the FFF 3D printed PEEK orbital mesh customized implants with a metric considering the design variants, biomechanical, and morphological parameters. We then studied the performance of the implants as a function of varying thicknesses and porous design constructs through a finite element (FE) based computational model and a decision matrix based statistical approach. The maximum stress values achieved in our results predicted the high durability of the implants. In all the implant profile configurations, the maximum deformation values were under one-tenth of a millimeter (mm) domain. The circular patterned design variant implant revealed the best performance score. The study further demonstrated that compounding multi-design computational analysis with 3D printing can be beneficial for the optimal restoration of the orbital floor. In the framework of the current thesis, the potential clinical application of material extrusion-based 3D printing for PEEK customized implants at the POC was demonstrated. We implemented clinical experience and engineering principles to generate a technical roadmap from preoperative medical imaging datasets to virtual surgical planning, computer-aided design models of various reconstructive implant variants, to the fabrication of PEEK PSIs using FFF 3D printing technology. The integration of 3D printing PEEK implants at the POC entails numerous benefits, including a collaborative team approach, quicker turnaround time of customized implants, support in pre-surgical and intraoperative planning, improved patient outcomes, and decreased overall healthcare cost. We believe that FFF 3D printing of customized PEEK implants could become an integral part of the hospitals and holds potential for various reconstructive surgery applications

안면 비대칭 교정을 위한 악교정 수술에서 전두단면 하악지 경사의 의도적 변화시 정확성과 안정성

학위논문(석사) -- 서울대학교대학원 : 치과대학 치의과학과, 2022. 8. Jin Young Choi .목적: 안면 비대칭 교정을 위한 악교정 수술에서 전방 하악지 경사(FRI)의 의도적인 변화의 정확성과 안정성을 평가한다. 방 법: 안면비대칭을 동반한 골격성 III급 부정교합 진단으로, 의도적인 전방 하악지 경사도 수정을 동반한 악교정 수술을 시행 받은 20명의 환자(5명의 남성, 15명의 여성)를 대상으로 하였다. 각 환자는 술전 2-3주, 술후 3일(T1)과 6개월(T2)에 각각 콘빔전산화단층촬영(Cone-Beam Computed Tomography, CBCT)을 시행하였다. 가상 수술 계획을 세웠으며, 가상 수술 데이터(Tv) 상에서 좌우 양측의 전방 하악지 경사도를 측정하였다. 전방 하악지 경사도 수정의 정확성은 가상 수술 데이터와 술후 3일 데이터의 차이(∆T1-Tv)를, 수정된 전방 하악지 경사도의 안정성은 술후 3일과 6개월의 차이(∆T2-T1)를 계산하여 평가하였다. 결 과: 모든 수술은 성공적으로 시행되었고, 모든 환자들에서 계획된 최종교합으로 유도되었으며 안면 비대칭 또한 개선되었다. 전방 하악지 경사도 수정의 정확성(ΔT1-Tv)은 0.87 ± 0.25˚, (p> 0.05, p=0.69) 수정된 전방 하악지 경사도의 안정성(ΔT2-T1)은 0.58 ± 0.34˚, (p> 0.05, p=0.50) 로 측정되었다. 요약: 악교정 수술 시 컴퓨터를 사용한 가상 수술과 CAD/CAM을 활용하여 의도적 전방 하악지 경사도 수정이 계획대로 수술에 반영되었으며, 또한 안정적으로 유지할 수 있는 것으로 평가된다Objective: To assess the accuracy and stability of intentional change of frontal ramal inclination (FRI) in orthognathic surgery for the correction of facial asymmetry. Materials and methods: The study included 20 patients (5 males and 15 females) who were diagnosed as skeletal Class III malocclusion with facial asymmetry, underwent orthognathic surgery including intentional change of FRI for the correction of facial asymmetry, and had Cone-Beam Computed Tomography (CBCT) 2 – 3 weeks before surgery, 3 days after surgery (T1), and 6 months after surgery (T2). After performing virtual surgical planning, the data of virtual surgical planning (Tv) was utilized to assess the right and left FRI one time. The accuracy of FRI correction (∆T1-Tv) and the stability of corrected FRI (∆T2 -T1) was evaluated. Results: Surgery was successful for all the patients. All patients achieved good final occlusion and facial asymmetry were resolved. The mean absolute value of accuracy of FRI correction (ΔT1-Tv) and the stability of corrected FRI (ΔT2 –T1) were 0.87 ± 0.25˚ and 0.58 ± 0.34˚, respectively. No statistically significant values were found in both accuracy and stability. Conclusion: Results indicated that computer aided design and computer aided manufacturing (CAD/CAM) assisted orthognathic surgery might have a high degree of surgical precision and stability of intentional change of FRITable of contents Acknowledgments II Abstract III Abbreviations in this study VI Introduction and background 2 Materials and methods 6 Methods: 7 1- Acquisition of skull and dentition data for virtual surgical planning 7 2- Procedure of virtual surgical planning including intentional change of FRI 7 3- Fabrication of computer-aided design and computer -aided manufacturing – made customized surgical guide stents, wafer, and customized titanium plates 8 4- Orthognathic surgery 9 5- Evaluation of the accuracy of intentional change of FRI 9 6- Evaluation of the Stability superimposed of FRI 10 Data analysis: 10 Results 11 Discussion 12 References 18 List of figures 24 List of tables 28 국문초록 31석

Novel indirect additive manufacturing for processing biomaterials

PhD ThesisThe aim of this work was to identify methods for the production of patient-specific biomedical devices via indirect additive manufacturing (AM) methods. Additive manufacturing has been shown to provide a good solution for the manufacture of patient specific implants, but in a limited range of materials, and at a relatively high cost. This research project considered what are known as “indirect” AM approaches, which typically consider AM in combination with one or more subsequent processes in order to produce a part, with a maxillofacial plate and mandible resection used as a demonstrator application. Three different approaches were considered: (i) using AM to produce moulds for powder pressing of bioceramic green parts for subsequent sintering; (ii) using AM to produce moulds for biopolymer sintering; and (iii) 3D printing of bioceramic powders into green parts for subsequent sintering. Apatite wollastonite glass ceramic (AW) and poly-Lactide-co-glycolide (PLGA) were selected as the bioceramic and biopolymer materials to process. These were characterised before and after processing in order to ensure that the processing route did not affect the material properties. Geometric dimensions, the morphological structure and mechanical properties were studied to establish the accuracy, shrinkage and strength of the fabricated biomaterial implants. The use of AM processes to produce moulds for PLGA sintering, and the 3D printing of bioceramic powders formed the best overall results in terms of the definition and properties of the manufactured parts. Parts produced were accurate to within 5% of the as designed dimensions for both the PLGA sintering and the bioceramic powders 3D printing. The indirect AM methods are considered to be promising processing routes for medical devices.University Malaysia Perlis and the Malaysian Higher Education Ministr

Optimization of a Patient-Specific External Fixation Device for Lower Limb Injuries

From MDPI via Jisc Publications RouterHistory: accepted 2021-08-02, pub-electronic 2021-08-10Publication status: PublishedFunder: Engineering and Physical Sciences Research Council; Grant(s): EP/R01513/1Funder: King Saud University; Grant(s): RSP-2021/299The use of external fixation devices is considered a valuable approach for the treatment of bone fractures, providing proper alignment to fractured fragments and maintaining fracture stability during the healing process. The need for external fixation devices has increased due to an aging population and increased trauma incidents. The design and fabrication of external fixations are major challenges since the shape and size of the defect vary, as well as the geometry of the human limb. This requires fully personalized external fixators to improve its fit and functionality. This paper presents a methodology to design personalized lightweight external fixator devices for additive manufacturing. This methodology comprises data acquisition, Computer tomography (CT) imaging analysis and processing, Computer Aided Design (CAD) modelling and two methods (imposed predefined patterns and topology optimization) to reduce the weight of the device. Finite element analysis with full factorial design of experiments were used to determine the optimal combination of designs (topology optimization and predefined patterns), materials (polylactic acid, acrylonitrile butadiene styrene, and polyamide) and thickness (3, 4, 5 and 6 mm) to maximize the strength and stiffness of the fixator, while minimizing its weight. The optimal parameters were found to correspond to an external fixator device optimized by topology optimization, made in polylactic acid with 4 mm thickness

Book of Abstracts 15th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering and 3rd Conference on Imaging and Visualization

In this edition, the two events will run together as a single conference, highlighting the strong connection with the Taylor & Francis journals: Computer Methods in Biomechanics and Biomedical Engineering (John Middleton and Christopher Jacobs, Eds.) and Computer Methods in Biomechanics and Biomedical Engineering: Imaging and Visualization (JoãoManuel R.S. Tavares, Ed.). The conference has become a major international meeting on computational biomechanics, imaging andvisualization. In this edition, the main program includes 212 presentations. In addition, sixteen renowned researchers will give plenary keynotes, addressing current challenges in computational biomechanics and biomedical imaging. In Lisbon, for the first time, a session dedicated to award the winner of the Best Paper in CMBBE Journal will take place. We believe that CMBBE2018 will have a strong impact on the development of computational biomechanics and biomedical imaging and visualization, identifying emerging areas of research and promoting the collaboration and networking between participants. This impact is evidenced through the well-known research groups, commercial companies and scientific organizations, who continue to support and sponsor the CMBBE meeting series. In fact, the conference is enriched with five workshops on specific scientific topics and commercial software.info:eu-repo/semantics/draf