Three-dimensional aortic aneurysm model and endovascular repair: an educational tool for surgical trainees

3D-Printing of Drug-Eluting Implants: An Overview of the Current Developments Described in the Literature

The usage of 3D-printing for drug-eluting implants combines the advantages of a targeted local drug therapy over longer periods of time at the precise location of the disease with a manufacturing technique that easily allows modifications of the implant shape to comply with the individual needs of each patient. Research until now has been focused on several aspects of this topic such as 3D-printing with different materials or printing techniques to achieve implants with different shapes, mechanical properties or release profiles. This review is intended to provide an overview of the developments currently described in the literature. The topic is very multifaceted and several of the investigated aspects are not related to just one type of application. Consequently, this overview deals with the topic of 3D-printed drug-eluting implants in the application fields of stents and catheters, gynecological devices, devices for bone treatment and surgical screws, antitumoral devices and surgical meshes, as well as other devices with either simple or complex geometry. Overall, the current findings highlight the great potential of the manufacturing of drug-eluting implants via 3D-printing technology for advanced individualized medicine despite remaining challenges such as the regulatory approval of individualized implants.

Transcending Dimensions: a Comparative Analysis of Cloaca Imaging in Advancing the Surgeon's Understanding of Complex Anatomy

Surgeons have a steep learning capacity to understand 2-D images provided by conventional cloacagrams. Imaging advances now allow for 3-D reconstruction and 3-D models; but no evaluation of the value of these techniques exists in the literature. Therefore, we sought to determine if advances in 3-D imaging would benefit surgeons, lead to accelerated learning, and improve understanding for operative planning of a cloaca reconstruction. Questionnaires were used to assess the understanding of 2-D and 3-D images by pediatric surgical faculty and trainees. For the same case of a cloacal malformation, a 2D contrast study cloacagram, a 3D model rotatable CT scan reconstruction, a software enhanced 3D video animation (which allowed the observer to manipulate the structure in any orientation), and a printed physical 3D cloaca model that could be held in the observer's hand were employed. Logistic mixed effect models assessed whether the proportion of questions about the case that were answered correctly differed by imaging modality, and whether the proportion answered correctly differed between trainee and attending surgeons for any particular modality. Twenty-nine pediatric surgery trainees (27 pediatric general surgery and 2 pediatric urology surgery trainees) and 30 pediatric surgery and urology faculty participated. For trainees, the percentage of questions answered correctly was: 2-D 10.5%, 3-D PACS 46.7%, 3-D Enhanced 67.1%, and 3-D Printed 73.8%. For faculty, the total percentage of questions answered correctly was: 2-D 22.2%, 3-D PACS 54.8%, 3D Enhanced 66.2%, and 3-D printed 74.0%. The differences in rates of correctness across all four modalities were significant in both fellows and attendings (p < 0.001), with performance being lowest for the 2-D modality, and with increasing percentage of correct answers with each subsequent modality. The difference between trainees and attendings in correctness rate was significant only for the 2-D modality, with attendings answering correctly more often. The 2-D cloacagram, as the least complex model, was the most difficult to interpret. The more complex the modality, the more correct were the responses obtained from both groups. Trainees and attendings had similar levels of correct answers and understanding of the cloacagram for the more advanced modalities. Mental visualization skills of anatomy and complex 3-D spatial arrangements traditionally have taken years of experience to master. Now with novel surgical education resources of a 3-D cloacagram, a more quickly advancing skill is possible.

Learn EVAR sizing from scratch: The results of a one-day intensive course in EVAR sizing and stent graft selection for vascular trainees

Background and aim

Recognition of structured training in endovascular aortic repair (EVAR) for vascular trainees is increasing. Nevertheless, how trainees can achieve sufficient skills in EVAR sizing and graft selection is sparsely described. The aim of this study was to investigate the effect of systematic training in basic EVAR sizing and graft selection on vascular surgery trainees using a validated assessment tool.

Methods

Sixteen vascular surgery trainees were included in an intensive 6-h hands-on workshop in aortic sizing and stent graft selection for EVAR with a trainer-to-trainee ratio of 1:2. After 1-h lecture, participants did 5 h of supervised training on increasingly complex cases. Finally, the participants were tested using a validated assessment tool.

Results

All participants were able to size the test-case and select a stent graft combination in 24:35 (13:30–48:20) min (median and range). The participants’ overall test scores (lower is better) were in median 17.9 (11.9–28.4). This did not differ from the scores of experienced EVAR operators 14.7 (11.7–25.2) (<200 EVAR’s) ( p = .32) but was inferior to the score of EVAR experts 11.2 (9.8 –18.7) (≥200 EVAR’s) ( p = .01). The sub-score for anatomical measurements was 10.6 (3.9–18.8) and comparable with the experienced group 9.7 (8.1–12.8) ( p = .83) but inferior to the expert operators 6.5 (5.2–10.2) ( p = .04). The sub-score for stent graft selection was 7.5 (4.9–14.1) and comparable with experienced operators scoring 4.5 (3.6–12.3) ( p = .09) but inferior to the expert operators score of 5.0 (3.6–8.4) ( p = .01).

Conclusion

This study presents the results of a standardised one-day basic EVAR sizing and graft selection workshop. Vascular surgery trainees with no prior EVAR experience learned to size and select stent grafts for a simple infra-renal AAA on par with experienced EVAR operators.

Interventional radiology training: where will technology take us?

Interventional radiology is a relatively young specialty, and it is undergoing a period of considerable growth. The benefits of a minimally invasive approach are clear, with smaller incisions, less pain, and faster recovery times being the principal benefits compared to surgical alternatives.

Trainees need to acquire the technical skills and the clinical acumen to accurately deliver targeted treatment and safely follow up patients after the procedure. The need to maintain an efficient interventional radiology service whilst also giving sufficient time for trainee education is a challenge. In order to compensate for this, novel technologies like virtual reality (VR), augmented reality (AR), cadaveric simulation, and three-dimensional (3D) printing have been postulated as a means of supplementing training.

In this article, we outline the main features of these innovative strategies and discuss the evidence base behind them. Benefits of these techniques beyond pure clinical training include the standardization of educational cases, access to training at any time, and less risk to patients. The main disadvantage is the large financial outlay required. Therefore, before widespread uptake can be recommended, further research is needed to confirm the educational benefit of these novel techniques, both in and of themselves and in comparison to existing clinical-based education.

3D printing of aortic models as a teaching tool for improving understanding of aortic disease

BACKGROUND

A geometrical understanding of the individual patient's disease morphology is crucial in aortic surgery. The aim of our study was to validate a questionnaire addressing understanding of aortic disease and use this questionnaire to investigate the value of 3D printing as a teaching tool for surgical trainees.

METHODS

Anonymized CT-angiography images of six different patients were selected as didactic cases of aortic disease and made into 3D models of transparent rigid resin with the Vat-photopolymerization technique. The 3D aortic models, which could be disassembled and reassembled, were displayed to 37 surgical trainees, immediately after a seminar on aortic disease. A questionnaire was developed to compare the trainees' understanding before (T0) and after (T1) demonstration of the 3D printed models.

RESULTS

A panel of 15 experts participated in evaluating face and content validity of the questionnaire. The questionnaire validity was established and therefore the information investigated by the questionnaire could be synthetized using the mean of the items to indicate the understanding. The participants (mean age 28 years, range 26-34, male 59%) showed a significant improvement in understanding from T0 (median=7.25; IQR=1.50) to T1 (median=8.00; IQR=1.50; P=0.002).

CONCLUSIONS

Preliminary data suggest that the use of 3D-printed aortic models as a teaching tool was feasible and improved the understanding of aortic disease among surgical trainees.

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

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.

Artificial vascular models for endovascular training (3D printing)

The endovascular technique has led to a revolution in the care of patients with vascular disease; however, acquiring and maintaining proficiency over a broad spectrum of procedures is challenging. Three-dimensional (3D) printing technology allows the production of models that can be used for endovascular training. This article aims to explain the process and technologies available to produce vascular models for endovascular training, using 3D printing technology. The data are based on the group experience and a review of the literature. Different 3D printing methods are compared, describing their advantages, disadvantages and potential roles in surgical training. The process of 3D printing a vascular model based on an imaging examination consists of the following steps: image acquisition, image post-processing, 3D printing and printed model post-processing. The entire process can take a week. Prospective studies have shown that 3D printing can improve surgical planning, especially in complex endovascular procedures, and allows the production of efficient simulators for endovascular training, improving residents’ surgical performance and self-confidence.

The Various Applications of 3D Printing in Cardiovascular Diseases

PURPOSE OF REVIEW

To highlight the various applications of 3D printing in cardiovascular disease and discuss its limitations and future direction.

RECENT FINDINGS

Use of handheld 3D printed models of cardiovascular structures has emerged as a facile modality in procedural and surgical planning as well as education and communication. Three-dimensional (3D) printing is a novel imaging modality which involves creating patient-specific models of cardiovascular structures. As percutaneous and surgical therapies evolve, spatial recognition of complex cardiovascular anatomic relationships by cardiologists and cardiovascular surgeons is imperative. Handheld 3D printed models of cardiovascular structures provide a facile and intuitive road map for procedural and surgical planning, complementing conventional imaging modalities. Moreover, 3D printed models are efficacious educational and communication tools. This review highlights the various applications of 3D printing in cardiovascular diseases and discusses its limitations and future directions.

Three-dimensional (3D) printing and its applications for aortic diseases

Three-dimensional (3D) printing is a process which generates prototypes from virtual objects in computer-aided design (CAD) software. Since 3D printing enables the creation of customized objects, it is a rapidly expanding field in an age of personalized medicine. We discuss the use of 3D printing in surgical planning, training, and creation of devices for the treatment of aortic diseases. 3D printing can provide operators with a hands-on model to interact with complex anatomy, enable prototyping of devices for implantation based upon anatomy, or even provide pre-procedural simulation. Potential exists to expand upon current uses of 3D printing to create personalized implantable devices such as grafts. Future studies should aim to demonstrate the impact of 3D printing on outcomes to make this technology more accessible to patients with complex aortic diseases.

3D Printing Applications in Minimally Invasive Spine Surgery

3D printing (3DP) technology continues to gain popularity among medical specialties as a useful tool to improve patient care. The field of spine surgery is one discipline that has utilized this; however, information regarding the use of 3DP in minimally invasive spine surgery (MISS) is limited. 3D printing is currently being utilized in spine surgery to create biomodels, hardware templates and guides, and implants. Minimally invasive spine surgeons have begun to adopt 3DP technology, specifically with the use of biomodeling to optimize preoperative planning. Factors limiting widespread adoption of 3DP include increased time, cost, and the limited range of diagnoses in which 3DP has thus far been utilized. 3DP technology has become a valuable tool utilized by spine surgeons, and there are limitless directions in which this technology can be applied to minimally invasive spine surgery.

3D Printing is a Transformative Technology in Congenital Heart Disease

Survival in congenital heart disease has steadily improved since 1938, when Dr. Robert Gross successfully ligated for the first time a patent ductus arteriosus in a 7-year-old child. To continue the gains made over the past 80 years, transformative changes with broad impact are needed in management of congenital heart disease. Three-dimensional printing is an emerging technology that is fundamentally affecting patient care, research, trainee education, and interactions among medical teams, patients, and caregivers. This paper first reviews key clinical cases where the technology has affected patient care. It then discusses 3-dimensional printing in trainee education. Thereafter, the role of this technology in communication with multidisciplinary teams, patients, and caregivers is described. Finally, the paper reviews translational technologies on the horizon that promise to take this nascent field even further.

Patient-Specific Surgical Implants Made of 3D Printed PEEK: Material, Technology, and Scope of Surgical Application

Additive manufacturing (AM) is rapidly gaining acceptance in the healthcare sector. Three-dimensional (3D) virtual surgical planning, fabrication of anatomical models, and patient-specific implants (PSI) are well-established processes in the surgical fields. Polyetheretherketone (PEEK) has been used, mainly in the reconstructive surgeries as a reliable alternative to other alloplastic materials for the fabrication of PSI. Recently, it has become possible to fabricate PEEK PSI with Fused Filament Fabrication (FFF) technology. 3D printing of PEEK using FFF allows construction of almost any complex design geometry, which cannot be manufactured using other technologies. In this study, we fabricated various PEEK PSI by FFF 3D printer in an effort to check the feasibility of manufacturing PEEK with 3D printing. Based on these preliminary results, PEEK can be successfully used as an appropriate biomaterial to reconstruct the surgical defects in a “biomimetic” design.

Vascular CT and MRI: a practical guide to imaging protocols

Non-invasive cross-sectional imaging techniques play a crucial role in the assessment of the varied manifestations of vascular disease. Vascular imaging encompasses a wide variety of pathology. Designing vascular imaging protocols can be challenging owing to the non-uniform velocity of blood in the aorta, differences in cardiac output between patients, and the effect of different disease states on blood flow. In this review, we provide the rationale behind—and a practical guide to—designing and implementing straightforward vascular computed tomography (CT) and magnetic resonance imaging (MRI) protocols.

Teaching Points

• There is a wide range of vascular pathologies requiring bespoke imaging protocols.

• Variations in cardiac output and non-uniform blood velocity complicate vascular imaging.

• Contrast media dose, injection rate and duration affect arterial enhancement in CTA.

• Iterative CT reconstruction can improve image quality and reduce radiation dose.

• MRA is of particular value when imaging small arteries and venous studies.

Clinical Applications of 3D Printing: Primer for Radiologists

Three-dimensional (3D) printing refers to a number of manufacturing technologies that create physical models from digital information. Radiology is poised to advance the application of 3D printing in health care because our specialty has an established history of acquiring and managing the digital information needed to create such models. The 3D Printing Task Force of the Radiology Research Alliance presents a review of the clinical applications of this burgeoning technology, with a focus on the opportunities for radiology. Topics include uses for treatment planning, medical education, and procedural simulation, as well as patient education. Challenges for creating custom implantable devices including financial and regulatory processes for clinical application are reviewed. Precedent procedures that may translate to this new technology are discussed. The task force identifies research opportunities needed to document the value of 3D printing as it relates to patient care.

Creating vascular models by postprocessing computed tomography angiography images: a guide for anatomical education

BACKGROUND

A new application of teaching anatomy includes the use of computed tomography angiography (CTA) images to create clinically relevant three-dimensional (3D) printed models. The purpose of this article is to review recent innovations on the process and the application of 3D printed models as a tool for using under and post-graduate medical education.

METHODS

Images of aortic arch pattern received by CTA were converted into 3D images using the Google SketchUp free software and were saved in stereolithography format. Using a 3D printer (Makerbot), a model mode polylactic acid material was printed.

RESULTS

A two-vessel left aortic arch was identified consisting of the brachiocephalic trunk and left subclavian artery. The life-like 3D models were rotated 360° in all axes in hand.

CONCLUSIONS

The early adopters in education and clinical practices have embraced the medical imaging-guided 3D printed anatomical models for their ability to provide tactile feedback and a superior appreciation of visuospatial relationship between the anatomical structures. Printed vascular models are used to assist in preoperative planning, develop intraoperative guidance tools, and to teach patients surgical trainees in surgical practice.

Applications of 3D printing in cardiovascular diseases

3D-printed models fabricated from CT, MRI, or echocardiography data provide the advantage of haptic feedback, direct manipulation, and enhanced understanding of cardiovascular anatomy and underlying pathologies. Reported applications of cardiovascular 3D printing span from diagnostic assistance and optimization of management algorithms in complex cardiovascular diseases, to planning and simulating surgical and interventional procedures. The technology has been used in practically the entire range of structural, valvular, and congenital heart diseases, and the added-value of 3D printing is established. Patient-specific implants and custom-made devices can be designed, produced, and tested, thus opening new horizons in personalized patient care and cardiovascular research. Physicians and trainees can better elucidate anatomical abnormalities with the use of 3D-printed models, and communication with patients is markedly improved. Cardiovascular 3D bioprinting and molecular 3D printing, although currently not translated into clinical practice, hold revolutionary potential. 3D printing is expected to have a broad influence in cardiovascular care, and will prove pivotal for the future generation of cardiovascular imagers and care providers. In this Review, we summarize the cardiovascular 3D printing workflow, from image acquisition to the generation of a hand-held model, and discuss the cardiovascular applications and the current status and future perspectives of cardiovascular 3D printing.

3D-printing techniques in a medical setting: a systematic literature review

BACKGROUND

Three-dimensional (3D) printing has numerous applications and has gained much interest in the medical world. The constantly improving quality of 3D-printing applications has contributed to their increased use on patients. This paper summarizes the literature on surgical 3D-printing applications used on patients, with a focus on reported clinical and economic outcomes.

METHODS

Three major literature databases were screened for case series (more than three cases described in the same study) and trials of surgical applications of 3D printing in humans.

RESULTS

227 surgical papers were analyzed and summarized using an evidence table. The papers described the use of 3D printing for surgical guides, anatomical models, and custom implants. 3D printing is used in multiple surgical domains, such as orthopedics, maxillofacial surgery, cranial surgery, and spinal surgery. In general, the advantages of 3D-printed parts are said to include reduced surgical time, improved medical outcome, and decreased radiation exposure. The costs of printing and additional scans generally increase the overall cost of the procedure.

CONCLUSION

3D printing is well integrated in surgical practice and research. Applications vary from anatomical models mainly intended for surgical planning to surgical guides and implants. Our research suggests that there are several advantages to 3D-printed applications, but that further research is needed to determine whether the increased intervention costs can be balanced with the observable advantages of this new technology. There is a need for a formal cost-effectiveness analysis.

Medical 3D Printing for the Radiologist

While use of advanced visualization in radiology is instrumental in diagnosis and communication with referring clinicians, there is an unmet need to render Digital Imaging and Communications in Medicine (DICOM) images as three-dimensional (3D) printed models capable of providing both tactile feedback and tangible depth information about anatomic and pathologic states. Three-dimensional printed models, already entrenched in the nonmedical sciences, are rapidly being embraced in medicine as well as in the lay community. Incorporating 3D printing from images generated and interpreted by radiologists presents particular challenges, including training, materials and equipment, and guidelines. The overall costs of a 3D printing laboratory must be balanced by the clinical benefits. It is expected that the number of 3D-printed models generated from DICOM images for planning interventions and fabricating implants will grow exponentially. Radiologists should at a minimum be familiar with 3D printing as it relates to their field, including types of 3D printing technologies and materials used to create 3D-printed anatomic models, published applications of models to date, and clinical benefits in radiology. Online supplemental material is available for this article.

A Pilot Study Assessing the Impact of 3-D Printed Models of Aortic Aneurysms on Management Decisions in EVAR Planning

Introduction:

Endovascular repair of aortic aneurysms with difficult anatomy is challenging. There is no consensus for planning such procedures.

Methods:

Six cases of aortic aneurysms with challenging anatomical features, such as short, angulated, and conical necks and tortuous iliacs were harvested. The computed tomography (CT) scans were anonymized. Lifesize 3-dimensional (3-D) printed models were created of the lumen. Endovascular operators were asked to review the CT angiography (CTA), make a management plan, and give an indication of their confidence. They were then presented with the equivalent model and asked to review their decision. Their attitudes to such models were briefly surveyed.

Results:

A total of 28 endovascular operators reviewed 144 cases. After review of the physical model, the management plan changed in 29 (20.1%) of 144 cases. Initial plan after CTA review was endovascular 73.6%, open repair 22.9%, and second opinion 3.5%. After model review, this became endovascular 67.4%, open repair 19.4%, and second opinion 4.8%. Although the general trend was toward more open procedures, off-label techniques reduced from 19.4% to 15.2% following model review. When the management plan did not change, level of confidence did increase in 37 (43.5%) of 85 cases. The majority of operators stated that they would find models useful for planning in some procedures. For 1 case, the change in the percentage of participants being sure in the management plan was statistically significant ( P = .031).

Conclusion:

The 3-D printed models may be potentially useful in planning cases with EVAR. It is a paradigm that warrants further investigation.

Novel application of rapid prototyping for simulation of bronchoscopic anatomy

OBJECTIVE

The authors used rapid prototyping (RP) technology to create anatomically congruent models of tracheo-bronchial tree for teaching relevant bronchoscopic anatomy.

DESIGN

Pilot study.

SETTING

A single level tertiary academic medical center.

INTERVENTIONS

Two 3 dimensional (3D) models of tracheo-bronchial tree (one showing normal anatomy and another with an early take off of right apical bronchus) were recreated from Computed Tomographic images using RP technology. These images were then attached to mannequins and examined with a flexible fiberoptic bronchoscope (FFB). These images were then compared with the actual FFB images obtained during lung isolation.

MEASUREMENTS AND MAIN RESULTS

The images obtained through the 3D models were found to be congruent to actual patient anatomy.

CONCLUSIONS

RP can be successfully used to create anatomically accurate models from imaging studies. There is potential for RP to become a valuable educational tool in the future.