scholarly journals Improving mandibular reconstruction by using topology optimization, patient specific design and additive manufacturing?—A biomechanical comparison against miniplates on human specimen

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0253002
Author(s):  
Jan J. Lang ◽  
Mirjam Bastian ◽  
Peter Foehr ◽  
Michael Seebach ◽  
Jochen Weitz ◽  
...  
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Dynamic Testing ◽  
Mandibular Reconstruction ◽  
Patient Specific ◽  
Reconstruction Process ◽  
Cadaveric Specimen ◽  
Custom Made ◽  
Significant Difference ◽  
Titanium Grade

In this study, topology optimized, patient specific osteosynthesis plates (TOPOS-implants) are evaluated for the mandibular reconstruction using fibula segments. These shape optimized implants are compared to a standard treatment with miniplates (thickness: 1.0 mm, titanium grade 4) in biomechanical testing using human cadaveric specimen. Mandible and fibula of 21 body donors were used. Geometrical models were created based on automated segmentation of CT-scans of all specimens. All reconstructions, including cutting guides for osteotomy as well as TOPOS-implants, were planned using a custom-made software tool. The TOPOS-implants were produced by electron beam melting (thickness: 1.0 mm, titanium grade 5). The fibula-reconstructed mandibles were tested in static and dynamic testing in a multi-axial test system, which can adapt to the donor anatomy and apply side-specific loads. Static testing was used to confirm mechanical similarity between the reconstruction groups. Force-controlled dynamic testing was performed with a sinusoidal loading between 60 and 240 N (reconstructed side: 30% reduction to consider resected muscles) at 5 Hz for up to 5 · 105 cycles. There was a significant difference between the groups for dynamic testing: All TOPOS-implants stayed intact during all cycles, while miniplate failure occurred after 26.4% of the planned loading (1.32 · 105 ± 1.46 · 105 cycles). Bone fracture occurred in both groups (miniplates: n = 3, TOPOS-implants: n = 2). A correlation between bone failure and cortical bone thickness in mandible angle as well as the number of bicortical screws used was demonstrated. For both groups no screw failure was detected. In conclusion, the topology optimized, patient specific implants showed superior fatigue properties compared to miniplates in mandibular reconstruction. Additionally, the patient specific shape comes with intrinsic guiding properties to support the reconstruction process during surgery. This demonstrates that the combination of additive manufacturing and topology optimization can be beneficial for future maxillofacial surgery.

scholarly journals Qualification of Customised Medical Implants Produced by Ti6Al4V(ELI) Additive Manufacturing

2020 ◽  
Vol 321 ◽  
pp. 03012
Author(s):  
W B du Preez ◽  
G J Booysen
Keyword(s):  
Additive Manufacturing ◽  
Quality Management ◽  
Management System ◽  
Quality Management System ◽  
Titanium Implants ◽  
International Standards ◽  
Patient Specific ◽  
Medical Implants ◽  
Design Development ◽  
Custom Made

Although many cases of medical implants produced through additive manufacturing (AM) in Ti6Al4V have been reported in literature, most of these processes had not been qualified. To enable certification and commercialisation of medical implants and devices an ISO 13485:2016 quality management system was successfully implemented in the Centre for Rapid Prototyping and Manufacturing (CRPM) at the Central University of Technology, Free State in South Africa. This certification covers qualification of both design, development and production of patient specific custom made titanium implants, as well as preoperative models, jigs and cutting guides in nylon by means of AM and supports commercialisation. With this quality management system as framework for ensuring the reliability and repeatability of the AM performed at the CRPM, the generation of data to validate the individual processes in the AM process chain was pursued. Sufficient research data has been produced and published to prove that medical implants produced through AM can fully comply with the international standards for material, physical, chemical and mechanical properties. In this paper the research performed towards the qualification of AM of Ti6Al4V medical implants is discussed. Examples are given of internationally leading work on utilising these implants in maxillofacial and orthopaedic surgeries.

Establishing a Quality Management System for Production of Certified Customised Titanium Medical Implants through Additive Manufacturing

MRS Advances ◽  
2020 ◽  
Vol 5 (26) ◽  
pp. 1387-1396
Author(s):  
W B du Preez ◽  
D J de Beer ◽  
G J Booysen
Keyword(s):  
Additive Manufacturing ◽  
Quality Management ◽  
Management System ◽  
Quality Management System ◽  
Titanium Implants ◽  
Patient Specific ◽  
Medical Implants ◽  
Validation Data ◽  
Custom Made

ABSTRACTVarious cases of medical implants produced through additive manufacturing (AM) in Ti6Al4V have been reported in literature. Not all manufacturing processes used, were qualified. In striving to deliver certified AM medical implants and devices, an ISO 13485:2016 quality management system was implemented in the Centre for Rapid Prototyping and Manufacturing (CRPM) of the Central University of Technology, Free State (CUT) in Bloemfontein, South Africa. This certification is valid for design, development and production of patient-specific custom-made titanium implants, preoperative models, jigs and cutting-guides in nylon through AM, and contract-production of these products. For maintaining this quality management system, the generation of data to validate the individual processes in the AM process-chain is crucial to prove the DMLS product-quality of CRPM’s products. During the past five years, directed research data was produced and published to prove that medical implants produced through DMLS can fully comply with the accepted international standards for material, physical, chemical and mechanical properties of such parts. The paper discusses the quality management system’s establishment; materials research projects executed to generate validation data are mentioned; and examples of customised titanium implants for restoring the quality of life of patients are shown.

Patient-Specific Titanium Mandibular Reconstruction Using Additive Manufacturing

2018 ◽  
Author(s):  
Xia Yan ◽  
Zhi Chao Feng ◽  
Changchun Li ◽  
Heming Wu ◽  
Chunbo Tang ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Mandibular Reconstruction ◽  
Patient Specific

scholarly journals Towards a CAD-based automatic procedure for patient specific cutting guides to assist sternal osteotomies in pectus arcuatum surgical correction

2018 ◽  
Vol 6 (1) ◽  
pp. 118-127 ◽  
Author(s):  
Monica Carfagni ◽  
Flavio Facchini ◽  
Rocco Furferi ◽  
Marco Ghionzoli ◽  
Lapo Governi ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Surgical Correction ◽  
Patient Specific ◽  
Chest Wall Deformity ◽  
Surgical Guide ◽  
Surgical Guides ◽  
Custom Made ◽  
Cutting Guides ◽  
Manufacturing Techniques ◽  
The Right

Abstract Pectus Arcuatum, a rare congenital chest wall deformity, is characterized by the protrusion and early ossification of sternal angle thus configuring as a mixed form of excavatum and carinatum features. Surgical correction of pectus arcuatum always includes one or more horizontal sternal osteotomies, consisting in performing a V-shaped horizontal cutting of the sternum (resection prism) by means of an oscillating power saw. The angle between the saw and the sternal body in the V-shaped cut is determined according to the peculiarity of the specific sternal arch. The choice of the right angle, decided by the surgeon on the basis of her/his experience, is crucial for a successful intervention. The availability of a patient-specific surgical guide conveying the correct cutting angles can considerably improve the chances of success and, at the same time, reduce the intervention time. The present paper aims to propose a new CAD-based approach to design and produce custom-made surgical guides, manufactured by using additive manufacturing techniques, to assist the sternal osteotomy. Starting from CT images, the procedure allows to determine correct resection prism and to shape the surgical guide accordingly taking into account additive manufacturing capabilities. Virtually tested against three case studies the procedure demonstrated its effectiveness. Highlights Patient-specific surgical guide improves the chances of success in sternal osteotomy. A CAD-based approach to design and produce custom-made surgical guides is proposed. The proposed framework entails both a series of automatic and user-guided tasks.

Diffusion-Tensor Imaging Versus Digitization in Reconstructing the Masseter Architecture

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Cristina Falcinelli ◽  
Zhi Li ◽  
Wilfred W. Lam ◽  
Greg J. Stanisz ◽  
Anne M. Agur ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Diffusion Tensor ◽  
Three Dimensional ◽  
Heterogeneous Material ◽  
Patient Specific ◽  
Proton Density ◽  
Fe Modeling ◽  
Orientation Data ◽  
Cadaveric Specimen ◽  
Significant Difference

Accurate characterization of the craniomaxillofacial (CMF) skeleton using finite element (FE) modeling requires representation of complex geometries, heterogeneous material distributions, and physiological loading. Musculature in CMF FE models are often modeled with simple link elements that do not account for fiber bundles (FBs) and their differential activation. Magnetic resonance (MR) diffusion-tensor imaging (DTI) enables reconstruction of the three-dimensional (3D) FB arrangement within a muscle. However, 3D quantitative validation of DTI-generated FBs is limited. This study compares 3D FB arrangement in terms of pennation angle (PA) and fiber bundle length (FBL) generated through DTI in a human masseter to manual digitization. CT, MR-proton density, and MR-DTI images were acquired from a single cadaveric specimen. Bone and masseter surfaces were reconstructed from CT and MR-proton density images, respectively. PA and FBL were estimated from FBs reconstructed from MR-DTI images using a streamline tracking (STT) algorithm (n = 193) and FBs identified through manual digitization (n = 181) and compared using the Mann–Whitney test. DTI-derived PAs did not differ from the digitized data (p = 0.411), suggesting that MR-DTI can be used to simulate FB orientation and the directionality of transmitted forces. Conversely, a significant difference was observed in FBL (p < 0.01) which may have resulted due to the tractography stopping criterion leading to early tract termination and greater length variability. Overall, this study demonstrated that DTI can yield muscle FB orientation data suitable to representative directionality of physiologic muscle loading in patient-specific CMF FE modeling.

scholarly journals 3D Printed Personalized Corneal Models as a Tool for Improving Patient’s Knowledge of an Asymmetric Disease

Symmetry ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 151 ◽  
Author(s):  
Jose S. Velázquez ◽  
Francisco Cavas ◽  
José M. Bolarín ◽  
Jorge L. Alió
Keyword(s):  
Clinical Practice ◽  
Additive Manufacturing ◽  
Open Source ◽  
3D Model ◽  
Clinical Service ◽  
Communication Strategy ◽  
Patient Specific ◽  
Custom Made ◽  
Patient Assistance ◽  
3D Printed

Additive manufacturing is a vanguard technology that is currently being used in several fields in medicine. This study aims to evaluate the viability in clinical practice of a patient-specific 3D model that helps to improve the strategies of the doctor-patient assistance. Data obtained from a corneal topographer were used to make a virtual 3D model by using CAD software, to later print this model by FDM and get an exact replica of each patient’s cornea in consultation. Used CAD and printing software were open-source, and the printing material was biodegradable and its cost was low. Clinic users gave their feedback by means of a survey about their feelings when perceiving with their senses their own printed cornea. There was 82 surveyed, 73.8% (9.74; SD: 0.45) of them considered that the model had helped them a lot to understand their disease, expressing 100% of them their intention of taking home the printed model. The majority highlighted that this new concept improves both quality and clinical service in consultation. Custom-made individualized printed models allow a new patient-oriented perspective that may improve the communication strategy from the ophthalmologist to the patient, easing patient’s understanding of their asymmetric disease and its later treatment.

Regeneration von Knochendefekten mit computergesteuerter Herstellung von Gerüstträgern

2013 ◽  
Vol 22 (03) ◽  
pp. 180-187 ◽  
Author(s):  
J. Henke ◽  
J. T. Schantz ◽  
D. W. Hutmacher
Keyword(s):  
Tissue Engineering ◽  
Additive Manufacturing ◽  
Custom Made

ZusammenfassungDie Behandlung ausgedehnter Knochen-defekte nach Traumata oder durch Tumoren stellt nach wie vor eine signifikante Heraus-forderung im klinischen Alltag dar. Aufgrund der bestehenden Limitationen aktueller Therapiestandards haben Knochen-Tissue-Engineering (TE)-Verfahren zunehmend an Bedeutung gewonnen. Die Entwicklung von Additive-Manufacturing (AM)-Verfahren hat dabei eine grundlegende Innovation ausgelöst: Durch AM lassen sich dreidimensionale Gerüstträger in einem computergestützten Schichtfür-Schicht-Verfahren aus digitalen 3D-Vorlagen erstellen. Wurden mittels AM zunächst nur Modelle zur haptischen Darstellung knöcherner Pathologika und zur Planung von Operationen hergestellt, so ist es mit der Entwicklung nun möglich, detaillierte Scaffoldstrukturen zur Tissue-Engineering-Anwendung im Knochen zu fabrizieren. Die umfassende Kontrolle der internen Scaffoldstruktur und der äußeren Scaffoldmaße erlaubt eine Custom-made-Anwendung mit auf den individuellen Knochendefekt und die entsprechenden (mechanischen etc.) Anforderungen abgestimmten Konstrukten. Ein zukünftiges Feld ist das automatisierte ultrastrukturelle Design von TE-Konstrukten aus Scaffold-Biomaterialien in Kombination mit lebenden Zellen und biologisch aktiven Wachstumsfaktoren zur Nachbildung natürlicher (knöcherner) Organstrukturen.

Numerical Analysis of the VAD Outflow Cannula Positioning on the Blood Flow in the Patient–Specific Brain Supplying Arteries

2020 ◽  
Vol 22 (2) ◽  
pp. 619-636 ◽  
Author(s):  
Zbigniew Tyfa ◽  
Damian Obidowski ◽  
Krzysztof Jóźwik
Keyword(s):  
Blood Flow ◽  
Computer Aided Design ◽  
Volume Flow Rate ◽  
Flow Distribution ◽  
Primary Objective ◽  
Patient Specific ◽  
Blood Flow Distribution ◽  
Reconstruction Process ◽  
Outflow Cannula ◽  
The Brain

AbstractThe primary objective of this research can be divided into two separate aspects. The first one was to verify whether own software can be treated as a viable source of data for the Computer Aided Design (CAD) modelling and Computational Fluid Dynamics CFD analysis. The second aspect was to analyze the influence of the Ventricle Assist Device (VAD) outflow cannula positioning on the blood flow distribution in the brain-supplying arteries. Patient-specific model was reconstructed basing on the DICOM image sets obtained with the angiographic Computed Tomography. The reconstruction process was performed in the custom-created software, whereas the outflow cannulas were added in the SolidWorks software. Volumetric meshes were generated in the Ansys Mesher module. The transient boundary conditions enabled simulating several full cardiac cycles. Performed investigations focused mainly on volume flow rate, shear stress and velocity distribution. It was proven that custom-created software enhances the processes of the anatomical objects reconstruction. Developed geometrical files are compatible with CAD and CFD software – they can be easily manipulated and modified. Concerning the numerical simulations, several cases with varied positioning of the VAD outflow cannula were analyzed. Obtained results revealed that the location of the VAD outflow cannula has a slight impact on the blood flow distribution among the brain supplying arteries.

An evaluation of a shoulder rehabilitation class in a UK hospital following evidence-based modifications

2021 ◽  
pp. 1-8
Author(s):  
Emily Kell ◽  
John A. Hammond ◽  
Sophie Andrews ◽  
Christina Germeni ◽  
Helen Hingston ◽  
...  
Keyword(s):  
Patient Satisfaction ◽  
Shoulder Pain ◽  
Management Strategies ◽  
Cost Effective ◽  
Rehabilitation Programme ◽  
Patient Specific ◽  
Satisfaction Survey ◽  
Evidence Based ◽  
Patient Satisfaction Survey ◽  
Significant Difference

OBJECTIVES: Shoulder pain is a common musculoskeletal disorder, which carries a high cost to healthcare systems. Exercise is a common conservative management strategy for a range of shoulder conditions and can reduce shoulder pain and improve function. Exercise classes that integrate education and self-management strategies have been shown to be cost-effective, offer psycho-social benefits and promote self-efficacy. This study aimed to examine the effectiveness of an 8-week educational and exercise-based shoulder rehabilitation programme following the introduction of evidence-based modifications. METHODS: A retrospective evaluation of a shoulder rehabilitation programme at X Trust was conducted, comparing existing anonymised Shoulder Pain and Disability Index (SPADI) and Patient-Specific Functional Scale (PSFS) scores from two cohorts of class participants from 2017-18 and 2018-19 that were previously collected by the physiotherapy team. Data from the two cohorts were analysed separately, and in comparison, to assess class efficacy. Descriptive data were also analysed from a patient satisfaction survey from the 2018-19 cohort. RESULTS: A total of 47 patients completed the 8-week shoulder rehabilitation programme during the period of data collection (2018-2019). The 2018-19 cohort showed significant improvements in SPADI (p 0.001) and PSFS scores (p 0.001). No significant difference was found between the improvements seen in the 2017-18 cohort and the 2018-19 cohort. 96% of the 31 respondents who completed the patient satisfaction survey felt the class helped to achieve their goals. CONCLUSION: A group-based shoulder rehabilitation class, which included loaded exercises and patient education, led to improvements in pain, disability and function for patients with rotator cuff related shoulder pain (RCRSP) in this outpatient setting, but anticipated additional benefits based on evidence were not observed.

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