Feasibility of an endovascular training and research environment with exchangeable patient specific 3D printed vascular anatomy

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

BACKGROUND

Medical three-dimensional (3D) printing has demonstrated utility and value in anatomic models for vascular conditions. A writing group composed of the Radiological Society of North America (RSNA) Special Interest Group on 3D Printing (3DPSIG) provides appropriateness recommendations for vascular 3D printing indications.

METHODS

A structured literature search was conducted to identify all relevant articles using 3D printing technology associated with vascular indications. Each study was vetted by the authors and strength of evidence was assessed according to published appropriateness ratings.

RESULTS

Evidence-based recommendations for when 3D printing is appropriate are provided for the following areas: aneurysm, dissection, extremity vascular disease, other arterial diseases, acute venous thromboembolic disease, venous disorders, lymphedema, congenital vascular malformations, vascular trauma, vascular tumors, visceral vasculature for surgical planning, dialysis access, vascular research/development and modeling, and other vasculopathy. Recommendations are provided in accordance with strength of evidence of publications corresponding to each vascular condition combined with expert opinion from members of the 3DPSIG.

CONCLUSION

This consensus appropriateness ratings document, created by the members of the 3DPSIG, provides an updated reference for clinical standards of 3D printing for the care of patients with vascular conditions.

3D printing in the planning and teaching of endovascular procedures

BACKGROUND

The introduction of 3D printing in the medical field led to new possibilities in the planning of complex procedures, as well as new ways of training junior physicians. Especially in the field of vascular interventions, 3D printing has a wide range of applications.

METHODOLOGICAL INNOVATIONS

3D-printed models of aortic aneurysms can be used for procedural training of endovascular aortic repair (EVAR), which can help boost the physician's confidence in the procedure, leading to a better outcome for the patient. Furthermore, it allows for a better understanding of complex anatomies and pathologies. In addition to teaching applications, the field of pre-interventional planning benefits greatly from the addition of 3D printing. Especially in the preparation for a complex endovascular aortic repair, prior orientation and test implantation of the stent grafts can further improve outcomes and reduce complications. For both teaching and planning applications, high-quality imaging datasets are required that can be transferred into a digital 3D model and subsequently printed in 3D. Thick slice thickness or suboptimal contrast agent phase can reduce the overall detail of the digital model, possibly concealing crucial anatomical details.

CONCLUSION

Based on the digital 3D model created for 3D printing, another new visualization technique might see future applications in the field of vascular interventions: virtual reality (VR). It enables the physician to quickly visualize a digital 3D model of the patient's anatomy in order to assess possible complications during endovascular repair. Due to the short transfer time from the radiological dataset into the VR, this technique might see use in emergency situations, where there is no time to wait for a printed model.

Radiation-free Thoracic Endovascular Aneurysm Repair with Fiberoptic and Electromagnetic Guidance:A Phantom Study

PURPOSE

The purpose of this study was to evaluate the feasibility and accuracy of a radiation-free implantation of a thoracic aortic stent-graft employing fiberoptic and electromagnetic tracking in an anthropomorphic phantom.

MATERIALS AND METHODS

An anthropomorphic phantom was manufactured based on computed tomography angiography (CTA) data from a patient. An aortic stent-graft application system was equipped with a fiber Bragg gratings fiber and three electromagnetic sensors. The stent-graft was navigated in the phantom by three interventionalists using the tracking data generated by both technologies. One implantation procedure was performed. The technical success of the procedure was evaluated using digital subtraction angiography and pre- and post-interventional CTA. Tracking accuracy was determined at various anatomical landmarks based on separately acquired fluoroscopic images. The mean/maximum errors were measured for the stent-graft application system and the tip/end of the stent-graft.

RESULTS

The procedure resulted in technical success with a mean error below 3 mm for the entire application system and <2 mm for the position of the tip of the stent-graft. Navigation/implantation and handling of the device were rated sufficiently accurate and on a par with comparable, routinely used stent-graft application systems.

CONCLUSION

Our study demonstrates successful stent-graft implantation during a thoracic endovascular aortic repair procedure employing advanced guidance techniques and avoiding fluoroscopic imaging. This is an essential step in facilitating the implantation of stent-grafts and reducing the health risks associated with ionizing radiation during endovascular procedures.

Creation of 3D anatomical models illustrating an intact and centrally torn triangular fibrocartilage complex for patient education prior treatment

BACKGROUND

The triangular fibrocartilage complex (TFCC) is a composite structure located in the human wrist and is made up from fibrocartilage and ligaments. It consists of eight distinct structures, with the ligamentous structures acting as the major stabilizer of the distal radioulnar joint and with the articular disc acting as a shock absorber at the ulnocarpal joint. The articular disc can be called the triangular fibrocartilage (TFC). Thus, traumatic injuries of the TFCC ligamentous structures cause instability of the joint and a centrally torn TFC disc causes ulnar sided wrist pain. TFCC pathologies can be difficult for patients to understand in clinic, due to their complex three-dimensional (3D) nature. The purpose of this study was to produce 3D anatomical models illustrating the normal anatomy of the wrist joint with the TFCC structure and a pathological model with a centrally torn TFC. These models would be used in a hand clinic to aid explanation of this complex three-dimensional anatomical structure and their injury to patients and trainee doctors.

MATERIALS

Three fresh frozen forearm and hand specimens were dissected, 3D scanned, 3D printed and painted. These models were introduced into a hand clinic to aid explanation of the complex anatomical structures, with the first 50 patients being asked, on a visual analog scale of 0-10, to state how much the models helped their understanding of the condition.

RESULTS

Three 3D printed anatomical models were produced to illustrate the (1) forearm muscles and wrist tendons, (2) an intact TFC and (3) a centrally torn TFC. 48 of 50 patients surveyed completed the scale, with an average rating of 8.7 increase in understanding with the models.

CONCLUSION

Patient education and understanding is crucial as it enhances decision making between surgeon and patient. These 3D anatomical models were shown to increase patient's understanding of the pathology. This should consequentially improve discussions on corresponding treatment options during consultation.

Utility of 3D printed abdominal aortic aneurysm phantoms: a systematic review

BACKGROUND

3D printed (3DP) abdominal aortic aneurysm (AAA) phantoms are emerging in the literature as an adjunct for the visualization of complex anatomy, particularly for presurgical device selection and simulation. This is the first systematic review to provide a comprehensive overview of 3DP for endovascular aneurysm repair (EVAR) planning and intervention, evaluating the readiness of current levels of technology for mainstream implementation.

METHODS

A systematic literature search of PubMed and MEDLINE was performed as per PRISMA guidelines using the terms '3D Printing', 'AAA' OR 'EVAR' and related index terms, and further relevant articles were appraised via a snowballing approach. Our last search was conducted on 14 November 2020.

RESULTS

Twenty-five articles were identified for critical analysis, with 14 cases or technical reports. Nineteen publications utilized 3DP AAA phantoms to aid presurgical decision making, device selection and design. Four publications explored the utility of 3DP phantoms as EVAR trainers, and one publication examined the technology as a tool for patient education. Flexible, transparent phantoms were deemed most useful; however, the cost and availability of higher end machines limited accessibility.

CONCLUSION

3DP phantoms have been used in EVAR to facilitate visualization of complex patient anatomy, appropriate device selection, in predicting navigational difficulties and the shape and position of endograft after deployment. These phantoms show promise in reducing known complications such as endoleak, stent graft occlusion and migration; however, larger scale prospective studies are required to validate its impacts on patient outcomes and cost savings to the healthcare system.

Accuracy evaluation of patient-specific 3D-printed aortic anatomy

INTRODUCTION

3D printing has a wide range of applications in medicine. In surgery, this technique can be used for preoperative planning of complex procedures, production of patient specific implants, as well as training. However, accuracy evaluations of 3D vascular models are rare.

OBJECTIVES

Aim of this study was to investigate the accuracy of patient-specific 3D-printed aortic anatomies.

METHODS

Patients suffering from aorto-iliac aneurysms and with indication for treatment were selected on the basis of different anatomy and localization of the aneurysm in the period from January 1st 2014 to May 27th 2016. Six patients with aorto-iliac aneurysms were selected out of the database for 3D-printing. Subsequently, computed tomography (CT) images of the printed 3D-models were compared with the original CT data sets.

RESULTS

The mean deviation of the six 3D-vascular models ranged between -0.73 mm and 0.14 mm compared to the original CT-data. The relative deviation of the measured values showed no significant difference between the 3D-vascular and the original patient CT-data.

CONCLUSION

Our results showed that 3D printing has the potential to produce patient-specific 3D vascular models with reliable accuracy. This enables the use of such models for the development of new endovascular procedures and devices.

Novel Strategies in Artificial Organ Development: What Is the Future of Medicine?

The technology of tissue engineering is a rapidly evolving interdisciplinary field of science that elevates cell-based research from 2D cultures through organoids to whole bionic organs. 3D bioprinting and organ-on-a-chip approaches through generation of three-dimensional cultures at different scales, applied separately or combined, are widely used in basic studies, drug screening and regenerative medicine. They enable analyses of tissue-like conditions that yield much more reliable results than monolayer cell cultures. Annually, millions of animals worldwide are used for preclinical research. Therefore, the rapid assessment of drug efficacy and toxicity in the early stages of preclinical testing can significantly reduce the number of animals, bringing great ethical and financial benefits. In this review, we describe 3D bioprinting techniques and first examples of printed bionic organs. We also present the possibilities of microfluidic systems, based on the latest reports. We demonstrate the pros and cons of both technologies and indicate their use in the future of medicine.