The development of direct 3-dimensional printing of patient-specific mitral valve in soft material for simulation and procedural planning

Objectives

Replicating 3-dimensional prints of patient-specific mitral valves in soft materials is a cumbersome and time-consuming process. The aim of this study was to develop a method for a direct 3-dimensional printing of patient-specific mitral valves in soft material for simulation-based training and procedural planning.

Methods

A process was developed based on data acquisition using 3-dimensional transesophageal echocardiography Cartesian Digital Imaging and Communication of Medicine format, image processing using software (Vesalius3D, Blender, Meshlab, Atum3D Operation Station), and 3-dimensional printing using digital light processing, an additive manufacturing process based on photopolymer resins. Experiments involved adjustment of 3 variables: curing times, model thinness, and lattice structuring during the printing process. Printed models were evaluated for suitability in physical simulation by an experienced mitral valve surgeon.

Results

Direct 3-dimensional printing of a patient's mitral valve in soft material was completed within a range of 1.5 to 4.5 hours. Prints with postcuring times of 5, 7, 10, and 15 minutes resulted in increased stiffness. The mitral valves with 2.0-mm and 2.4-mm thinner leaflets felt more flexible without tear of the sutures through the material. The addition of lattice structures made the prints more compliant and better supported suturing.

Conclusions

Direct 3-dimensional printing of a realistic and flexible patient-specific mitral valve was achieved within a few hours. A combination of thinner leaflets, reduced curing time, and lattice structures enabled the creation of a realistic patient-specific mitral valve in soft material for physical simulation.

The Application of Precision Medicine in Structural Heart Diseases: A Step towards the Future

The personalized applications of 3D printing in interventional cardiology and cardiac surgery represent a transformative paradigm in the management of structural heart diseases. This review underscores the pivotal role of 3D printing in enhancing procedural precision, from preoperative planning to procedural simulation, particularly in valvular heart diseases, such as aortic stenosis and mitral regurgitation. The ability to create patient-specific models contributes significantly to predicting and preventing complications like paravalvular leakage, ensuring optimal device selection, and improving outcomes. Additionally, 3D printing extends its impact beyond valvular diseases to tricuspid regurgitation and non-valvular structural heart conditions. The comprehensive synthesis of the existing literature presented here emphasizes the promising trajectory of individualized approaches facilitated by 3D printing, promising a future where tailored interventions based on precise anatomical considerations become standard practice in cardiovascular care.

Three-dimensional printing of mitral valve models using echocardiographic data improves the knowledge of cardiology fellow physicians in training

Background

High fidelity three-dimensional Mitral valve models (3D MVM) printed from echocardiography are currently being used in preparation for surgical repair.

Aim

We hypothesize that printed 3DMVM could have relevance to cardiologists in training by improving their understanding of normal anatomy and pathology.

Methods

Sixteen fellow physicians in pediatric and adult cardiology training were recruited. 3D echocardiography (3DE) video clips of six mitral valves (one normal and five pathological) were displayed and the fellows were asked to name the prolapsing segments in each. Following that, three still images of 3D MVMs in different projections: enface, profile and tilted corresponding to the same MVs seen in the clip were presented on a screen. Participating physicians were presented with a comprehensive questionnaire aimed at assessing whether the 3D MVM has improved their understanding of valvular anatomy. Finally, a printed 3D MVM of each of the valves was handed out, and the same questionnaire was re-administered to identify any further improvement in the participants' perception of the anatomy.

Results

The correct diagnosis using the echocardiography video clip of the Mitral valve was attained by 45% of the study participants. Both pediatric and adult trainees, regardless of the year of training demonstrated improved understanding of the anatomy of MV after observing the corresponding model image. Significant improvement in their understanding was noted after participants had seen and physically examined the printed model.

Conclusion

Printed 3D MVM has a beneficial impact on the cardiology trainees' understanding of MV anatomy and pathology compared to 3DE images.

Fluid-structure interaction and structural simulation of high acceleration effects on surgical repaired human mitral valve biomechanics

Mitral valve dynamics depend on force stability in the mitral leaflets, the mitral annulus, the chordae tendineae, and the papillary muscles. In chordal rupture conditions, the proper function of the valve disrupts, causing mitral regurgitation, the most prevalent valvular disease. In this study, Structural and FSI frameworks were employed to study valve dynamics in healthy, pathologic, and repaired states. Anisotropic, non-linear, hyper-elastic material properties applied to tissues of the valve while the first-order Ogden model reflected the best compatibility with the empirical data. Hemodynamic blood pressure of the cardiovascular system is applied on the leaflets as uniform loads varying by time, and exposure to high acceleration loads imposed on models. Immersed boundary method used for simulation of fluid in a cardiac cycle. In comparison between healthy and pathologic models, stress values and chordal tensions are increased, by nearly threefold and twofold, respectively. Stress concentration on leaflets is reduced by 75% after performing a successful surgical repair on the pathological model. Crash acceleration loads led to more significant stress and chordae tension on models, by 27% and 23%, respectively. It is concluded that a more sophisticated model could lead to a better understanding of human heart valve biomechanics in various conditions. If a preoperative plan is developed based on these modeling methods, the requirement for multiple successive repairs would be eliminated, operative times are shortened, and patient outcomes are improved.

Transcatheter mitral valve replacement to treat severe calcified rheumatic native mitral stenosis: role of three-dimensional printing-a case report

Background

Rheumatic heart disease is a major disease that seriously affects human health and survival worldwide. Rheumatic mitral stenosis often has relatively complex pathological changes, and its progression leads to various manifestations of mitral valve dysfunction and adverse clinical events.

Case summary

We present a 60-year-old patient who developed chest tightness, shortness of breath, and bilateral lower limb oedema in 2018 (New York Heart Association functional class III). Systolic and diastolic murmurs could be heard in the mitral auscultation area. In December 2021, the patient was admitted to the hospital with stroke. Thereafter, transthoracic echocardiography and computed tomography were performed, and the progress of rheumatic mitral stenosis was recorded. Due to the patient's high surgical risk, a patient-specific three-dimensional printed model was used to observe anatomical structures and simulate main procedures, and the surgeons finally chose to perform transcatheter mitral valve replacement. The balloon-expandable bioprothesis was released from the right femoral artery to treat the rheumatic mitral stenosis. The patient remained asymptomatic at the 6-month follow-up.

Discussion

For patients with rheumatic mitral stenosis with high surgical risk, it is feasible to conduct transcatheter mitral valve replacement under the guidance of three-dimensional printing.

Three-dimensional printing in modelling mitral valve interventions

Mitral interventions remain technically challenging owing to the anatomical complexity and heterogeneity of mitral pathologies. As such, multi-disciplinary pre-procedural planning assisted by advanced cardiac imaging is pivotal to successful outcomes. Modern imaging techniques offer accurate 3D renderings of cardiac anatomy; however, users are required to derive a spatial understanding of complex mitral pathologies from a 2D projection thus generating an 'imaging gap' which limits procedural planning. Physical mitral modelling using 3D printing has the potential to bridge this gap and is increasingly being employed in conjunction with other transformative technologies to assess feasibility of intervention, direct prosthesis choice and avoid complications. Such platforms have also shown value in training and patient education. Despite important limitations, the pace of innovation and synergistic integration with other technologies is likely to ensure that 3D printing assumes a central role in the journey towards delivering personalised care for patients undergoing mitral valve interventions.

The evolution of technical prerequisites and local boundary conditions for optimization of mitral valve interventions-Emphasis on skills development and institutional risk performance

This viewpoint report describes how the evolution of transcatheter mitral valve intervention (TMVI) is influenced by lessons learned from three evolutionary tracks: (1) the development of treatment from mitral valve surgery (MVS) to transcutaneous procedures; (2) the evolution of biomedical engineering for research and development resulting in predictable and safe clinical use; (3) the adaptation to local conditions, impact of transcatheter aortic valve replacement (TAVR) experience and creation of infrastructure for skills development and risk management. Thanks to developments in computer science and biostatistics, an increasing number of reports regarding clinical safety and effectiveness is generated. A full toolbox of techniques, devices and support technology is now available, especially in surgery. There is no doubt that the injury associated with a minimally invasive access reduces perioperative risks, but it may affect the effectiveness of the treatment due to incomplete correction. Based on literature, solutions and performance standards are formulated with an emphasis in technology and positive outcome. Despite references to Heart Team decision making, boundary conditions such as hospital infrastructure, caseload, skills training and perioperative risk management remain underexposed. The role of Biomedical Engineering is exclusively defined by the Research and Development (R&D) cycle including the impact of human factor engineering (HFE). Feasibility studies generate estimations of strengths and safety limitations. Usability testing reveals user friendliness and safety margins of clinical use. Apart from a certification requirement, this information should have an impact on the definition of necessary skills levels and consequent required training. Physicians Preference Testing (PPT) and use of a biosimulator are recommended. The example of the interaction between two Amsterdam heart centers describes the evolution of a professional ecosystem that can facilitate innovation. Adaptation to local conditions in terms of infrastructure, referrals and reimbursement, appears essential for the evolution of a complete mitral valve disease management program. Efficacy of institutional risk management performance (IRMP) and sufficient team skills should be embedded in an appropriate infrastructure that enables scale and offers complete and safe solutions for mitral valve disease. The longstanding evolution of mitral valve therapies is the result of working devices embedded in an ecosystem focused on developing skills and effective risk management actions.

Application experience and research progress of different emerging technologies in plastic surgery

In the diagnosis and treatment of plastic surgery, there are structural processing problems, such as positioning, moving, and reconstructing complex three-dimensional structures. Doctors operate according to their own experience, and the inability to accurately locate these structures is an important problem in plastic surgery. Emerging digital technologies such as virtual reality, augmented reality, and three-dimensional printing are widely used in the medical field, particularly in plastic surgery. This article reviews the development of these three technical concepts, introduces the technical elements and specific applications required in plastic surgery, summarizes the application status of the three technologies in plastic surgery, and summarizes prospects for future development.

Mastering the learning curve of endoscopic mitral valve surgery

Endoscopic mitral valve surgery is a challenging procedure. Surgical volume is mandatory to achieve sufficient proficiency and superior results. To this date the learning curve has proven to be challenging. Offering high-fidelity simulation based training for both residents as experienced surgeons can help in establishing and enlarging surgical competences in shorter time without intraoperative trial and error.

Surgical Rehearsal for Mitral Valve Repair: Personalizing Surgical Simulation by 3D Printing

PURPOSE

The goal of this study was to show possible effects of performing the actual procedure of mitral valve repair (MVR) on personalized silicone models 1 day before operation.

DESCRIPTION

Based on preoperative 3-dimensional echocardiography recordings, flexible 3-dimensional replicas of the depicted pathologic mitral valves could be produced and used for a simulation of reconstructive techniques analogous to the upcoming MVR procedure. We integrated this step of personalized surgical planning into the clinical routine of 6 MVR cases with 3 different surgeons. This pilot study was assessed by evaluating questionnaires and by comparing isolated surgical steps with conventional MVRs.

EVALUATION

This approach was considered a better preparation for MVRs with overall positive responses from the surgeons. Simulation helped reduce the time of initial inspection of the valve because of better understanding of the valve's pathomorphologic features. Annuloplasty benefited from preoperative sizing by reducing the number of sizing attempts.

CONCLUSIONS

These initial findings suggest that simulation-based surgical planning can be implemented into patients' and physicians' clinical workflow as a major technologic advancement for future MVR preparation.

At the Crossroads of Minimally Invasive Mitral Valve Surgery—Benching Single Hospital Experience to a National Registry: A Plea for Risk Management Technology

Almost 30 years after the first endoscopic mitral valve repair, Minimally Invasive Mitral Valve Surgery (MIMVS) has become the standard at many institutions due to optimal clinical results and fast recovery. The question that arises is can already good results be further improved by an Institutional Risk Management Performance (IRMP) system in decreasing risks in minimally invasive mitral valve surgery (MIMVS)? As of yet, there are no reports on IRMP and learning systems in the literature. (2) Methods: We described and appraised our five-year single institutional experience with MIMVS in isolated valve surgery included in the Netherlands Heart Registry (NHR) and investigated root causes of high-impact complications. (3) Results: The 120-day and 12-month mortality were 1.1% and 1.9%, respectively, compared to the average of 4.3% and 5.3% reported in the NHR. The regurgitation rate was 1.4% compared to 5.2% nationwide. The few high-impact complications appeared not to be preventable. (4) Discussion: In MIMVS, freedom from major and minor complications is a strong indicator of an effective IRMP but remains concealed from physicians and patients, despite its relevance to shared decision making. Innovation adds to the complexity of MIMVS and challenges surgical competence. An IRMP system may detect and control new risks earlier. (5) Conclusion: An IRMP system contributes to an effective reduction of risks, pain and discomfort; provides relevant input for shared decision making; and warrants the safe introduction of new technology. Crossroads conclusions: investment in machine learning and AI for an effective IRMP system is recommended and the roles for commanding and operating surgeons should be considered.

Three dimensional modeling of atrioventricular valves provides predictive guides for optimal choice of prosthesis

Inaccuracies in intraoperative and preoperative measurements and estimations may lead to adverse outcomes such as patient-prosthesis mismatch. We aim to measure the relation between different dimensions of the atrioventricular valve complex in explanted porcine heart models. After a detailed physical morphology study, a cast of the explanted heart models was made using silicon-based materials. Digital models were obtained from three-dimensional scanning of the casts, showing the measured annulopapillary distance was 2.50 ± 0.18 cm, and 2.75 ± 0.36 cm for anterior and posterior papillary muscles of left ventricle, respectively. There was a significant linear association between the mitral annular circumference to anterior–posterior distance (p = 0.003, 95% CI 0.78–3.06), mitral annular circumference to interpapillary distance (p = 0.009, 95% CI 0.38–2.20), anterior–posterior distance to interpapillary distance (p = 0.02, 95% CI 0.10–0.78). Anterior–posterior distance appeared to be the most important predictor of mitral annular circumference compared to other measured distances. The mean length of the perpendicular distance of the tricuspid annulus, a, was 2.65 ± 0.54 cm; b was 1.77 ± 0.60 cm, and c was 3.06 ± 0.55 cm. Distance c was the most significant predictor for tricuspid annular circumference (p = 0.006, 95% CI 0.28–2.84). The anterior–posterior distance measured by three-dimensional scanning can safely be used to predict the annular circumference of the mitral valve. For the tricuspid valve, the strongest predictor for the circumference is the c-distance. Other measurements made from the positively correlated parameters may be extrapolated to their respective correlated parameters. They can aid surgeons in selecting the optimal prosthesis for the patients and improve procedural planning.

Translating Imaging Into 3D Printed Cardiovascular Phantoms

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3D printed patient specific phantoms can visualize complex cardiovascular anatomy

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Common imaging modalities for 3D printing are CCT and CMR

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Material jetting/PolyJet and stereolithography are widely used printing techniques

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Standardized validation is warranted to compare different 3D printing technologies

Translation of imaging into 3-dimensional (3D) printed patient-specific phantoms (3DPSPs) can help visualize complex cardiovascular anatomy and enable tailoring of therapy. The aim of this paper is to review the entire process of phantom production, including imaging, materials, 3D printing technologies, and the validation of 3DPSPs. A systematic review of published research was conducted using Embase and MEDLINE, including studies that investigated 3DPSPs in cardiovascular medicine. Among 2,534 screened papers, 212 fulfilled inclusion criteria and described 3DPSPs as a valuable adjunct for planning and guiding interventions (n = 108 [51%]), simulation of physiological or pathological conditions (n = 19 [9%]), teaching of health care professionals (n = 23 [11%]), patient education (n = 3 [1.4%]), outcome prediction (n = 6 [2.8%]), or other purposes (n = 53 [25%]). The most common imaging modalities to enable 3D printing were cardiac computed tomography (n = 131 [61.8%]) and cardiac magnetic resonance (n = 26 [12.3%]). The printing process was conducted mostly by material jetting (n = 54 [25.5%]) or stereolithography (n = 43 [20.3%]). The 10 largest studies that evaluated the geometric accuracy of 3DPSPs described a mean bias <±1 mm; however, the validation process was very heterogeneous among the studies. Three-dimensional printed patient-specific phantoms are highly accurate, used for teaching, and applied to guide cardiovascular therapy. Systematic comparison of imaging and printing modalities following a standardized validation process is warranted to allow conclusions on the optimal production process of 3DPSPs in the field of cardiovascular medicine.

Anatomical Engineering and 3D Printing for Surgery and Medical Devices: International Review and Future Exponential Innovations

Three-dimensional printing (3DP) has recently gained importance in the medical industry, especially in surgical specialties. It uses different techniques and materials based on patients' needs, which allows bioprofessionals to design and develop unique pieces using medical imaging provided by computed tomography (CT) and magnetic resonance imaging (MRI). Therefore, the Department of Biology and Medicine and the Department of Physics and Engineering, at the Bioastronautics and Space Mechatronics Research Group, have managed and supervised an international cooperation study, in order to present a general review of the innovative surgical applications, focused on anatomical systems, such as the nervous and craniofacial system, cardiovascular system, digestive system, genitourinary system, and musculoskeletal system. Finally, the integration with augmented, mixed, virtual reality is analyzed to show the advantages of personalized treatments, taking into account the improvements for preoperative, intraoperative planning, and medical training. Also, this article explores the creation of devices and tools for space surgery to get better outcomes under changing gravity conditions.

A soft functional mitral valve model prepared by three-dimensional printing as an aid for an advanced mitral valve operation

OBJECTIVES

The goal of this study was to build a soft mitral valve (MV) model for surgical simulation to aid with an advanced MV operation.

METHODS

Soft three-dimensional models of the MV were constructed by the mould-modelling method using silicone. The properties of the material used were tested and compared with those of the valve tissue. Then, the accuracy of the three-dimensional model was assessed from the perspectives of the pathological and morphological parameters. Thereafter, surgical simulation of MV repair, closure of the perforation and transcatheter MV replacement were simulated using our model. Two experienced surgeons were invited to perform and evaluate the fidelity and softness of the model. Morphological changes in the MV and the potential compression of the device on surrounding cardiac tissue were also measured after simulation.

RESULTS

The soft MV model was successfully constructed by the mould-modelling method. The property of the material used was closer to that of valve tissue than to that of the rigid model. In addition, the pathological details and morphological measurements of the three-dimensional model were consistent with the surgical findings. The simulated surgical procedure was successful using our model. Morphological changes, including the ratio of the leaflet/annulus area and the coaptation depth, were closely correlated with the regurgitation left after MV repair, which might be an indicator of the surgical effects. The results of this study demonstrated the great advantages of our constructed soft model in exploring the interaction of the device with the surrounding tissue. These advantages were not obtained using the rigid model in a previous study.

CONCLUSIONS

The soft MV model was successfully constructed using the mould-modelling method, and its physical properties were similar to those of heart tissue. In addition, the constructed model exhibited great advantages in surgical simulation and clinical application compared with the anatomical model.

The development of a flexible heart model for simulation-based training

OBJECTIVES

Simulation-based training has shown to be effective in training new surgical skills. The objective of this study is to develop a flexible 3-dimensional (3D)-printed heart model that can serve as a foundation for the simulation of multiple cardiovascular procedures.

METHODS

Using a pre-existing digital heart model, 3D transoesophageal echocardiography scans and a thoracic CT scan, a full volume new heart model was developed. The valves were removed from this model, and the internal structures were remodelled to make way for insertable patient-specific structures. Groves at the location of the coronaries were created using extrusion tools in a computer-modelling program. The heart was hollowed to create a more flexible model. A suitable material and thickness was determined using prior test prints. An aortic root and valve was built by segmenting the root from a thoracic CT scan and a valve from a transoesophageal echocardiogram. Segmentations were smoothed, small holes in the valves were filled and surrounding structures were removed to make the objects suitable for 3D printing.

RESULTS

A hollow 3D-printed heart model with the wall thicknesses of 1.5 mm and spaces to insert coronary arteries, valves and aortic roots in various sizes was successfully printed in flexible material.

CONCLUSIONS

A flexible 3D-printed model of the heart was developed onto which patient-specific cardiac structures can be attached to simulate multiple procedures. This model can be used as a platform for surgical simulation of various cardiovascular procedures.

Silicone models of the aortic root to plan and simulate interventions

OBJECTIVES

The objective of this work was to develop technology to create 'soft' patient-specific models of semilunar heart valves, the aortic valve in particular, suitable for training and simulation of surgical and endovascular interventions.

METHODS

Data obtained during routine cardiac contrast-enhanced multislice computed tomography were used to create 3-dimensional models of the aortic root. Three-dimensional models were used to create soft silicone models of the aortic root made by casting silicone into a negative mould printed with stereolithography. A comparison between the constructed models and the size of the aortic root was performed. We quantified how much time was needed for production of each model.

RESULTS

Four patient-specific soft models of the aortic root were produced. Data from patients of different ages and body surface areas were used as prototypes. All models had minimum size errors. During development of this technology, production time per model was reduced from 63 to 39 h.

CONCLUSIONS

We have demonstrated the feasibility of making soft patient-specific 3-dimensional aortic root models using currently available technology. These models can be used both for training physicians in a variety of open surgical and endovascular interventions and for the study of complex aortic root geometry.

Establishment of deformable three-dimensional printed models for laparoscopic right hemicolectomy in transverse colon cancer

BACKGROUND

Applications of three-dimensional (3-D) printed solid organ models for navigation and simulation were previously reported for abdominal surgeries, and their usefulness was shown by subjective evaluation. However, thus far, no study has examined the effect of intraoperative movements for tissue handling. Novel, deformable 3-D printed models of the superior mesenteric artery (SMA) and superior mesenteric vein (SMV) were created to optimize laparoscopic right hemicolectomy. The aim of this study was to establish a method using these individualized models for use in surgical practice.

METHODS

Deformable 3-D models for laparoscopic right hemicolectomy were created using a 3-D printing flexible filamentous material (thermoplastic polyurethane). Five patients with transverse colon cancer who underwent laparoscopic right hemicolectomy with D3 lymphadenectomy between April 2017 and September 2019 were enrolled in this study. Then, the created patient-specific models were compared with the previously recorded intraoperative video views.

RESULTS

Transverse colon mobilization changed the spatial arrangement of the branches of the SMA and SMV. The 3-D models reproduced the intraoperative view, although approaches to the dominant vessels to complete D3 lymphadenectomy may vary.

CONCLUSIONS

Deformable 3-D models of the SMA and SMV with added branches may aid in optimizing laparoscopic right hemicolectomy operations.

3D-printed anatomical models of the cystic duct and its variants, a low-cost solution for an in-house built simulator for laparoscopic surgery training

OBJECTIVES

To explore a method to create affordable anatomical models of the biliary tree that are adequate for training laparoscopic cholecystectomy with an in-house built simulator.

METHODS

We used a fused deposition modeling 3D printer to create molds of Acrylonitrile Butadiene Styrene (ABS) from Digital Imaging and Communication on Medicine (DICOM) images, and the molds were filled with silicone rubber. Thirteen surgeons with 4-5-year experience in the procedure evaluated the molds using a low-cost in-house built simulator utilizing a 5-point Likert-type scale.

RESULTS

Molds produced through this method had a consistent anatomical appearance and overall realism that evaluators agreed or definitely agreed (4.5/5). Evaluators agreed on recommending the mold for resident surgical training.

CONCLUSIONS

3D-printed molds created through this method can be applied to create affordable high-quality educational anatomical models of the biliary tree for training laparoscopic cholecystectomy.

Clinical situations for which 3D printing is considered an appropriate representation or extension of data contained in a medical imaging examination: adult cardiac conditions

BACKGROUND

Medical 3D printing as a component of care for adults with cardiovascular diseases has expanded dramatically. A writing group composed of the Radiological Society of North America (RSNA) Special Interest Group on 3D Printing (SIG) provides appropriateness criteria for adult cardiac 3D printing indications.

METHODS

A structured literature search was conducted to identify all relevant articles using 3D printing technology associated with a number of adult cardiac indications, physiologic, and pathologic processes. Each study was vetted by the authors and graded according to published guidelines.

RESULTS

Evidence-based appropriateness guidelines are provided for the following areas in adult cardiac care; cardiac fundamentals, perioperative and intraoperative care, coronary disease and ischemic heart disease, complications of myocardial infarction, valve disease, cardiac arrhythmias, cardiac neoplasm, cardiac transplant and mechanical circulatory support, heart failure, preventative cardiology, cardiac and pericardial disease and cardiac trauma.

CONCLUSIONS

Adoption of common clinical standards regarding appropriate use, information and material management, and quality control are needed to ensure the greatest possible clinical benefit from 3D printing. This consensus guideline document, created by the members of the RSNA 3D printing Special Interest Group, will provide a reference for clinical standards of 3D printing for adult cardiac indications.

Three-dimensional printing in adult cardiovascular medicine for surgical and transcatheter procedural planning, teaching and technological innovation

Three-dimensional (3D)-printing technologies in cardiovascular surgery have provided a new way to tailor surgical and percutaneous treatments. Digital information from standard cardiac imaging is integrated into physical 3D models for an accurate spatial visualization of anatomical details. We reviewed the available literature and analysed the different printing technologies, the required procedural steps for 3D prototyping, the used cardiac imaging, the available materials and the clinical implications. We have highlighted different materials used to replicate aortic and mitral valves, vessels and myocardial properties. 3D printing allows a heuristic approach to investigate complex cardiovascular diseases, and it is a unique patient-specific technology providing enhanced understanding and tactile representation of cardiovascular anatomies for the procedural planning and decision-making process. 3D printing may also be used for medical education and surgical/transcatheter training. Communication between doctors and patients can also benefit from 3D models by improving the patient understanding of pathologies. Furthermore, medical device development and testing can be performed with rapid 3D prototyping. Additionally, widespread application of 3D printing in the cardiovascular field combined with tissue engineering will pave the way to 3D-bioprinted tissues for regenerative medicinal applications and 3D-printed organs.

Simulation of a Right Anterior Thoracotomy Access for Aortic Valve Replacement Using a 3D Printed Model

OBJECTIVE

The right anterior lateral thoracotomy (RALT) approach for aortic valve replacement provides excellent outcomes in expert hands while avoiding sternal disruption. It, however, remains a technically demanding niche operation. Instrument trajectories via this access are influenced by patient anatomy, the intercostal space chosen, and surgical retraction maneuvers.

METHODS

To simulate the typical surgical maneuvers, on an anatomically accurate model, and to measure the instrument trajectories, we generated a 3-dimensional (3D) printed model of the heart and chest cavity. A simulated approach to the base of the right coronary sinus via the medial-second intercostal, the lateral-second intercostal, or third intercostal space was made. Keeping the instrument in place, 3D scans of the models and geometrical measurements of the instrument trajectories were performed.

RESULTS

The 3D scans of the 3D printed model showed a high fidelity when compared to the original computed tomographic scan image geometry (mean deviation of 1.26 ± 1.27mm). The instrument intrathoracic distance was 75 mm via the medial-second, 115 mm via the lateral-second, and 80 mm via the third intercostal space. The 3D angulation of the instrument to the incision was 33.77^o, 55.93^o, and 38.4^o respectively. The distance of the instrument to the lateral margin was 12, 26, and 5 mm respectively. The cranial margin of the incision was always a limiting margin for the instrument.

CONCLUSIONS

Three-dimensional printing and 3D scanning facilitated a realistic simulation of the instrument trajectory during RALT approach. The lateral-second intercostal approach showed the most favorable approach angle and distance from the lateral margin, although it also had the longest intrathoracic distance.

Mechanical Analysis of Ceramic/Polymer Composite with Mesh-Type Lightweight Design Using Binder-Jet 3D Printing

3D printing technology has recently been highlighted as an innovative manufacturing process. Among various 3D printing methods, binder jetting (BJ) 3D printing is particularly known as technology used to produce the complex sand mold quickly for a casting process. However, high manufacturing costs, due to its expensive materials, need to be lowered for more industrial applications of 3D printing. In this study, we investigated mechanical properties of sand molds with a lightweight structure for low material consumption and short process time. Our stress analysis using a computational approach, revealed a structural weak point in the mesh-type lightweight design applied to the 3D-printed ceramic/polymer composite.