Three-dimensional printing for perioperative planning of complex aortic arch surgery

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.

A Systematic Analysis of Additive Manufacturing Techniques in the Bioengineering of In Vitro Cardiovascular Models

Additive Manufacturing is noted for ease of product customization and short production run cost-effectiveness. As our global population approaches 8 billion, additive manufacturing has a future in maintaining and improving average human life expectancy for the same reasons that it has advantaged general manufacturing. In recent years, additive manufacturing has been applied to tissue engineering, regenerative medicine, and drug delivery. Additive Manufacturing combined with tissue engineering and biocompatibility studies offers future opportunities for various complex cardiovascular implants and surgeries. This paper is a comprehensive overview of current technological advancements in additive manufacturing with potential for cardiovascular application. The current limitations and prospects of the technology for cardiovascular applications are explored and evaluated.

3D printing in aortic endovascular therapies

Endovascular treatment of aortic disease, including aneurysm or dissection, is expanding at a rapid pace. Often, the specific patient anatomy in these cases is complex. Additive manufacturing, also known as three-dimensional (3D) printing, is especially useful in the treatment of aortic disease, due to its ability to manufacture physical models of complex patient anatomy. Compared to other surgical procedures, endovascular aortic repair can readily exploit the advantages of 3D printing with regard to operative planning and preoperative training. To date, there have been numerous uses of 3D printing in the treatment of aortic pathology as an adjunct in presurgical planning and as a basis for training modules for fellows and residents. In this review, we summarize the current uses of 3D printing in the endovascular management of aortic disease. We also review the process of producing these models, the limitations of their applications, and future directions of 3D printing in this field.

CT-Derived 3D Printing for Coronary Artery Cannulation Simulator Design Manufacturing

Mastering coronary angiography requires practice. Cadavers and animals do not accurately represent the human anatomical body, and practicing with actual patients has medical safety issues. Simulation offers safe and realistic conditions for cardiology intervention training. In this study, we propose a novel 3D printed simulator that contains physically realistic anatomy and has four access points. It increases safety for patients and students, and production is low-cost. We aimed to make and validate this simulator design as a prototype for coronary cannulation training. It was designed using computed tomography (CT) scan data of aorta, coronary, and heart models, and was printed by 3D printing with resin materials consisting of 75% or 85% clear resin and 25% or 15% flexible resin additive. The simulator was constructed with a camera above the simulator with a degree of LAO of 30°/0°, a display table, and an acrylic box. Twelve validators were interviewed for their expert opinions and analyzed by a qualitative method. They scored the simulator's suitability on a four-point Likert scale questionnaire. They described the simulator as having admirable values for all aspects (85.8%), curriculum suitability (92%), educational importance (94%), accuracy (83%), efficiency (78%), safety (87.5%), endurance (81.2%), aesthetics (80.7%), storage (85.4%), and affordability (85.8%).

Imaging-Based, Patient-Specific Three-Dimensional Printing to Plan, Train, and Guide Cardiovascular Interventions: A Systematic Review and Meta-Analysis

BACKGROUND

To tailor cardiovascular interventions, the use of three-dimensional (3D), patient-specific phantoms (3DPSP) encompasses patient education, training, simulation, procedure planning, and outcome-prediction.

AIM

This systematic review and meta-analysis aims to investigate the current and future perspective of 3D printing for cardiovascular interventions.

METHODS

We systematically screened articles on Medline and EMBASE reporting the prospective use of 3DPSP in cardiovascular interventions by using combined search terms. Studies that compared intervention time depending on 3DPSP utilisation were included into a meta-analysis.

RESULTS

We identified 107 studies that prospectively investigated a total of 814 3DPSP in cardiovascular interventions. Most common settings were congenital heart disease (CHD) (38 articles, 6 comparative studies), left atrial appendage (LAA) occlusion (11 articles, 5 comparative, 1 randomised controlled trial [RCT]), and aortic disease (10 articles). All authors described 3DPSP as helpful in assessing complex anatomic conditions, whereas poor tissue mimicry and the non-consideration of physiological properties were cited as limitations. Compared to controls, meta-analysis of six studies showed a significant reduction of intervention time in LAA occlusion (n=3 studies), and surgery due to CHD (n=3) if 3DPSPs were used (Cohen's d=0.54; 95% confidence interval, 0.13 to 0.95; p=0.001), however heterogeneity across studies should be taken into account.

CONCLUSIONS

3DPSP are helpful to plan, train, and guide interventions in patients with complex cardiovascular anatomy. Benefits for patients include reduced intervention time with the potential for lower radiation exposure and shorter mechanical ventilation times. More evidence and RCTs including clinical endpoints are needed to warrant adoption of 3DPSP into routine clinical practice.

A Call for Change. Can 3D Printing Replace Cadavers for Surgical Training?

While cadaveric dissection has stood the test of time because of its widely accepted educational value by experienced surgeons, the introduction advances in 3D printing and biomaterial technologies could potentially provide alternative tools for surgical training. This novel concept in simulation (physical reality) would encompass all the benefits of cadavers in terms of realism and clinical relevance without any of its ethical, infection, safety, and financial concerns.

A three-dimensional biomodel of type A aortic dissection for endovascular interventions

Thoracic endovascular aortic repair is widely used for type B aortic dissection. However, there is no favorable stent-graft for type A aortic dissection. A significant limitation for device development is the lack of an experimental model for type A aortic dissection. We developed a novel three-dimensional biomodel of type A aortic dissection for endovascular interventions. Based on Digital Imaging and Communication in Medicine data from the computed tomography image of a patient with a type A aortic dissection, a three-dimensional biomodel with a true lumen, a false lumen, and an entry tear located at the ascending aorta was created using laser stereolithography and subsequent vacuum casting. The biomodel was connected to a pulsatile mock circuit. We conducted four tests: an endurance test for clinical hemodynamics, wire insertion into the biomodel, rapid pacing, and simulation of stent-graft placement. The biomodel successfully simulated clinical hemodynamics; the target blood pressure and cardiac output were achieved. The guidewire crossed both true and false lumens via the entry tear. The pressure and flow dropped upon rapid pacing and recovered after it was stopped. This simulation biomodel detected decreased false luminal flow by stent-graft placement and detected residual leak. The three-dimensional biomodel of type A aortic dissection with a pulsatile mock circuit achieved target clinical hemodynamics, demonstrated feasibility for future use during the simulated endovascular procedure, and evaluated changes in the hemodynamics.

Utilizing 3D Printing and Hydrogel Casting for the Development of Patient-Specific Rehearsal Platforms for Robotic Assisted Partial Nephrectomies

BACKGROUND

Three-dimensional (3D) printing technology has been utilized to create patient-specific (PS) replicas as visual aids for surgical planning.^1-4 However, they cannot recreate the operative experience due to a lack of realistic tissue characteristics.

OBJECTIVES

Develop anatomically accurate, realistic, PS partial nephrectomy platforms suitable for pre-operative surgical rehearsals using 3D-printing and hydrogel casting.

MATERIAL

Patient CT scans were segmented into a computer-aided design (CAD) file and used to create injection casts. Kidney and tumor casts along with hollow vascular and urinary structures were 3D-printed. The hilar structures and tumor were registered into the kidney cast, injected with poly-vinyl alcohol (PVA) hydrogel, and processed to create the kidney phantom. Mechanical and functional testing protocols were completed to confirm that the properties of PVA matched the live tissue.⁵ Anatomical accuracy was confirmed by CT scanning the phantom and creating another CAD, which was compared to the original patient CAD. Full-procedural PS rehearsals were completed 24-48 hours prior to their respective live surgeries. Clinically relevant metrics (warm ischemia time, estimated blood loss, and positive surgical margins) from each rehearsal and live case were compared using a Wilcoxon-rank sum test.

RESULTS

The 7%-3freeze/thaw PVA best recreated the mechanical and functional properties of porcine kidneys, while anatomical verification showed ≤1 mm deviation of the kidney and tumor from the patient anatomy and ≤3 mm for the hilar structures. PS rehearsal platforms were fabricated using these methods for 8 patients (average tumor size 5.92 cm and nephrometry score 9.8). A positive correlation was found for warm ischemia time and estimated blood loss between rehearsals and live surgeries.

CONCLUSION

This reproducible method shows high anatomical accuracy, realistic tissue properties, and translational effects between rehearsals and live surgery. To determine the effects on patient outcomes, future studies will compare the impact of completing a pre-operative rehearsal vs standard surgical preparation.

Three-dimensional printing for cardiovascular diseases: from anatomical modeling to dynamic functionality

Three-dimensional (3D) printing is widely used in medicine. Most research remains focused on forming rigid anatomical models, but moving from static models to dynamic functionality could greatly aid preoperative surgical planning. This work reviews literature on dynamic 3D heart models made of flexible materials for use with a mock circulatory system. Such models allow simulation of surgical procedures under mock physiological conditions, and are; therefore, potentially very useful to clinical practice. For example, anatomical models of mitral regurgitation could provide a better display of lesion area, while dynamic 3D models could further simulate in vitro hemodynamics. Dynamic 3D models could also be used in setting standards for certain parameters for function evaluation, such as flow reserve fraction in coronary heart disease. As a bridge between medical image and clinical aid, 3D printing is now gradually changing the traditional pattern of diagnosis and treatment.

3D Printing Technologies: Recent Development and Emerging Applications in Various Drug Delivery Systems

The 3D printing is considered as an emerging digitized technology that could act as a key driving factor for the future advancement and precise manufacturing of personalized dosage forms, regenerative medicine, prosthesis and implantable medical devices. Tailoring the size, shape and drug release profile from various drug delivery systems can be beneficial for special populations such as paediatrics, pregnant women and geriatrics with unique or changing medical needs. This review summarizes various types of 3D printing technologies with advantages and limitations particularly in the area of pharmaceutical research. The applications of 3D printing in tablets, films, liquids, gastroretentive, colon, transdermal and intrauterine drug delivery systems as well as medical devices have been briefed. Due to the novelty and distinct features, 3D printing has the inherent capacity to solve many formulation and drug delivery challenges, which are frequently associated with poorly aqueous soluble drugs. Recent approval of Spritam® and publication of USFDA technical guidance on additive manufacturing related to medical devices has led to an extensive research in various field of drug delivery systems and bioengineering. The 3D printing technology could be successfully implemented from pre-clinical phase to first-in-human trials as well as on-site production of customized formulation at the point of care having excellent dose flexibility. Advent of innovative 3D printing machineries with built-in flexibility and quality with the introduction of new regulatory guidelines would rapidly integrate and revolutionize conventional pharmaceutical manufacturing sector.

Three-dimensional printing flexible models: a novel technique for Nuss procedure planning of pectus excavatum repair

Background

Pectus excavatum (PE), one of the most common congenital chest wall deformities, is characterized by posterior depression of the sternum and lower costal cartilages. In this study, we demonstrated the application of flexible three-dimensional printing thoracic models for surgical approach planning of extrapleural Nuss procedure for patients with pectus excavatum.

Methods

Six patients with pectus excavatum were referred to our hospital for extrapleural Nuss procedure. Each patient's chest was reconstructed based on their computed tomography imaging data, and the three-dimensional (3D) thoracic model was manufactured with flexible material using 3D printing technique. The individual surgical approach and custom-made steel bars were designed and produced using these models.

Results

The surgical approach was evaluated by using the three-dimensional thoracic model. In all patients received extrapleural Nuss surgery, it has been proven the uniformity of repair efficacy in both models and patients. Moreover, an individualized and well-fitting steel bar can be fabricated once the surgical approach was confirmed. All the steel bars were loaded against the ribs rigorously and seamlessly.

Conclusions

The flexible three-dimensional thoracic models were very helpful for the preoperative planning of extrapleural Nuss procedure.

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.

Additive manufacturing applications in cardiology: A review

BACKGROUND

Additive manufacturing (AM) has emerged as a serious planning, strategy, and education tool in cardiovascular medicine. This review describes and illustrates the application, development and associated limitation of additive manufacturing in the field of cardiology by studying research papers on AM in medicine/cardiology.

METHODS

Relevant research papers till August 2018 were identified through Scopus and examined for strength, benefits, limitation, contribution and future potential of AM. With the help of the existing literature & bibliometric analysis, different applications of AM in cardiology are investigated.

RESULTS

AM creates an accurate three-dimensional anatomical model to explain, understand and prepare for complex medical procedures. A prior study of patient's 3D heart model can help doctors understand the anatomy of the individual patient, which may also be used create training modules for institutions and surgeons for medical training.

CONCLUSION

AM has the potential to be of immense help to the cardiologists and cardiac surgeons for intervention and surgical planning, monitoring and analysis. Additive manufacturing creates a 3D model of the heart of a specific patient in lesser time and cost. This technology is used to create and analyse 3D model before starting actual surgery on the patient. It can improve the treatment outcomes for patients, besides saving their lives. Paper summarised additive manufacturing applications particularly in the area of cardiology, especially manufacturing of a patient-specific artificial heart or its component. Model printed by this technology reduces risk, improves the quality of diagnosis and preoperative planning and also enhanced team communication. In cardiology, patient data of heart varies from patient to patient, so AM technologies efficiently produce 3D models, through converting the predesigned virtual model into a tangible object. Companies explore additive manufacturing for commercial medical applications.

Three-dimensional printed degradable splint in the treatment of pulmonary artery sling associated with severe bilateral bronchus stenosis

Pulmonary artery sling is a congenital cardiovascular disease and is usually accompanied by tracheobronchial stenosis. Generally, infants diagnosed with pulmonary artery sling should have surgery. However, the treatment of tracheobronchial stenosis is still controversial. Our team developed a customised, degradable, three-dimensional printed splint and successfully applied it in the treatment of pulmonary artery sling associated with severe bilateral bronchus stenosis. We suggested that three-dimensional printing may be a novel and effective way to treat tracheobronchial stenosis and other diseases in children.

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.

The Role of Three-Dimensional Printing in Contemporary Vascular and Endovascular Surgery: A Systematic Review

BACKGROUND

Three-dimensional (3D) printing, also known as rapid prototyping or additive manufacturing, is a novel adjunct in the medical field. The aim of this systematic review is to evaluate the role of 3D printing technology in the field of contemporary vascular surgery in terms of its technical aspect, practicability, and clinical outcome.

METHODS

A systematic search of literatures published from January 1, 1980 to July 15, 2017 was identified from the EMBASE, MEDLINE, and Cochrane library database with reference to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline. The predefined selection inclusion criterion was clinical application of 3D printing technology in vascular surgery of large and small vessel pathology.

RESULTS

Forty-two articles were included in this systematic review, including 2 retrospective cohorts and 1 prospective case control study. 3D printing was mostly applied to abdominal aortic aneurysm (n = 20) and thoracic aorta pathology (n = 8), other vessels included celiac, splenic, carotid, subclavian, femoral artery, and portal vein (n = 10). The most commonly quoted materials were acrylonitrile-butadiene-styrene (n = 2), polylactic acid (n = 4), polyurethane resin (n = 3) and nylon (n = 3). The cost per replica ranged from USD $4-2,360. Cost for a commercial printer was around USD $2,210-50,000.

CONCLUSION

3D printing was recognized and gradually incorporated as a useful adjunct in the field of vascular and endovascular surgery. The production of an accurate anatomic patient-specific replica was shown to bring significant impact in patient management in terms of anatomic understanding, procedural planning, and intraoperative navigation, education, and academic research as well as patient communication. Further analysis on cost-effectiveness was indicated to guide decisions on applicability of such promising technology on a routine basis.

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 Modelling and Printing Technology to Produce Patient-Specific 3D Models

BACKGROUND

A comprehensive knowledge of mitral valve (MV) anatomy is crucial in the assessment of MV disease. While the use of three-dimensional (3D) modelling and printing in MV assessment has undergone early clinical evaluation, the precision and usefulness of this technology requires further investigation. This study aimed to assess and validate 3D modelling and printing technology to produce patient-specific 3D MV models.

METHODS

A prototype method for MV 3D modelling and printing was developed from computed tomography (CT) scans of a plastinated human heart. Mitral valve models were printed using four 3D printing methods and validated to assess precision. Cardiac CT and 3D echocardiography imaging data of four MV disease patients was used to produce patient-specific 3D printed models, and 40 cardiac health professionals (CHPs) were surveyed on the perceived value and potential uses of 3D models in a clinical setting.

RESULTS

The prototype method demonstrated submillimetre precision for all four 3D printing methods used, and statistical analysis showed a significant difference (p<0.05) in precision between these methods. Patient-specific 3D printed models, particularly using multiple print materials, were considered useful by CHPs for preoperative planning, as well as other applications such as teaching and training.

CONCLUSIONS

This study suggests that, with further advances in 3D modelling and printing technology, patient-specific 3D MV models could serve as a useful clinical tool. The findings also highlight the potential of this technology to be applied in a variety of medical areas within both clinical and educational settings.

3D printing from cardiovascular CT: a practical guide and review

Current cardiovascular imaging techniques allow anatomical relationships and pathological conditions to be captured in three dimensions. Three-dimensional (3D) printing, or rapid prototyping, has also become readily available and made it possible to transform virtual reconstructions into physical 3D models. This technology has been utilised to demonstrate cardiovascular anatomy and disease in clinical, research and educational settings. In particular, 3D models have been generated from cardiovascular computed tomography (CT) imaging data for purposes such as surgical planning and teaching. This review summarises applications, limitations and practical steps required to create a 3D printed model from cardiovascular CT.

Fabrication of arbitrary 3D components in cardiac surgery: from macro-, micro- to nanoscale

Fabrication of tissue-/organ-like structures at arbitrary geometries by mimicking the properties of the complex material offers enormous interest to the research and clinical applicability in cardiovascular diseases. Patient-specific, durable, and realistic three-dimensional (3D) cardiac models for anatomic consideration have been developed for education, pro-surgery planning, and intra-surgery guidance. In cardiac tissue engineering (TE), 3D printing technology is the most convenient and efficient microfabrication method to create biomimetic cardiovascular tissue for the potential in vivo implantation. Although booming rapidly, this technology is still in its infancy. Herein, we provide an emphasis on the application of this technology in clinical practices, micro- and nanoscale fabrications by cardiac TE. Initially, we will give an overview on the fabrication methods that can be used to synthesize the arbitrary 3D components with controlled features and will subsequently highlight the current limitations and future perspective of 3D printing used for cardiovascular diseases.

Three-dimensional Printed Cardiac Models: Applications in the Field of Medical Education, Cardiovascular Surgery, and Structural Heart Interventions

In recent years, three-dimensional (3D) printed models have been incorporated into cardiology because of their potential usefulness in enhancing understanding of congenital heart disease, surgical planning, and simulation of structural percutaneous interventions. This review provides an introduction to 3D printing technology and identifies the elements needed to construct a 3D model: the types of imaging modalities that can be used, their minimum quality requirements, and the kinds of 3D printers available. The review also assesses the usefulness of 3D printed models in medical education, specialist physician training, and patient communication. We also review the most recent applications of 3D models in surgical planning and simulation of percutaneous structural heart interventions. Finally, the current limitations of 3D printing and its future directions are discussed to explore potential new applications in this exciting medical field.

Use of 3D printer technology to facilitate surgical correction of a complex vascular anomaly with esophageal entrapment in a dog

A 10 week old female intact Staffordshire terrier was presented with a total of five congenital cardio-thoracic vascular anomalies consisting of a patent ductus arteriosus (PDA) with an aneurysmic dilation, pulmonic stenosis, persistent right aortic arch, aberrant left subclavian artery and persistent left cranial vena cava. These abnormalities were identified with a combination of echocardiogram and computed tomography angiography (CTA). The abnormalities were associated with esophageal entrapment, regurgitation, and volume overload of the left heart with left atrial and ventricular enlargement. A 2 cm diameter aneurysmic dilation at the junction of the PDA, right aortic arch and aberrant left subclavian artery presented an unusual surgical challenge and precluded simple circumferential ligation and transection of the structure. A full scale three dimensional model of the heart and vasculature was constructed from the CTA and plasma sterilized. The model was used preoperatively to facilitate surgical planning and enhance intraoperative communication and coordination between the surgical and anesthesia teams. Intraoperatively the model facilitated spatial orientation, atraumatic vascular dissection, instrument sizing and positioning. A thoracoabdominal stapler was used to close the PDA aneurysm prior to transection. At the four-month postoperative follow-up the patient was doing well. This is the first reported application of new imaging and modeling technology to enhance surgical planning when approaching correction of complex cardiovascular anomalies in a dog.

Surgical applications of three-dimensional printing: a review of the current literature & how to get started

Three dimensional (3D) printing involves a number of additive manufacturing techniques that are used to build structures from the ground up. This technology has been adapted to a wide range of surgical applications at an impressive rate. It has been used to print patient-specific anatomic models, implants, prosthetics, external fixators, splints, surgical instrumentation, and surgical cutting guides. The profound utility of this technology in surgery explains the exponential growth. It is important to learn how 3D printing has been used in surgery and how to potentially apply this technology. PubMed was searched for studies that addressed the clinical application of 3D printing in all surgical fields, yielding 442 results. Data was manually extracted from the 168 included studies. We found an exponential increase in studies addressing surgical applications for 3D printing since 2011, with the largest growth in craniofacial, oromaxillofacial, and cardiothoracic specialties. The pertinent considerations for getting started with 3D printing were identified and are discussed, including, software, printing techniques, printing materials, sterilization of printing materials, and cost and time requirements. Also, the diverse and increasing applications of 3D printing were recorded and are discussed. There is large array of potential applications for 3D printing. Decreasing cost and increasing ease of use are making this technology more available. Incorporating 3D printing into a surgical practice can be a rewarding process that yields impressive results.

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.

Using Three-Dimensional Printing to Fabricate a Tubing Connector for Dilation and Evacuation

BACKGROUND

This is a proof-of-concept study to show that simple instrumentation problems encountered in surgery can be solved by fabricating devices using a three-dimensional printer. The device used in the study is a simple tubing connector fashioned to connect two segments of suction tubing used in a surgical procedure where no commercially available product for this use is available through our usual suppliers in New Zealand.

MATERIALS AND METHODS

A cylindrical tubing connector was designed using three-dimensional printing design software. The tubing connector was fabricated using the Makerbot Replicator 2X three-dimensional printer. The connector was used in 15 second-trimester dilation and evacuation procedures. Data forms were completed by the primary operating surgeon. Descriptive statistics were used with the expectation that the device would function as intended in all cases.

EXPERIENCE

The three-dimensional printed tubing connector functioned as intended in all 15 instances.

CONCLUSION

Commercially available three-dimensional printing technology can be used to overcome simple instrumentation problems encountered during gynecologic surgical procedures.

The Use of Three-dimensional Printers for Partial Adrenalectomy: Estimating the Resection Limits

OBJECTIVE

To avoid hormonal replacement after partial adrenalectomy (PA), establishing the precise limit of an adrenal gland resection is essential. Herein, we evaluated the use of three-dimensional (3D) adrenal gland printing and volumetry measurement before PA to improve the determination of the remnant gland volume.

METHODS

Concomitant total adrenalectomy and a contralateral PA were performed in a patient with primary macronodular adrenal hyperplasia that exhibited mild hypercortisolism, arterial hypertension, and diabetes. Before surgery, a 3D replica of the adrenal gland to be partially resected was printed and given to the surgeon. The volumetry of the gland was measured by computed tomography 3D image reconstruction.

RESULTS

No postoperative complications were noted. Immediately after the surgery, the patient initiated corticosteroid replacement, which was interrupted 52 days later. At the 6-month follow-up, the patient stopped using medications for diabetes and reduced the number of antihypertensive medications from 5 to 1. The pre- and postoperative serum cortisol levels were, respectively, 28 and 8.7 mcg/dl (n 5-25 mcg/dl). The pre- and postoperative adrenocorticotropic hormone levels were, respectively, <5 and 88 pg/ml (n 7.2-63 pg/ml). The postoperative adrenal volume was 12% of the total preoperative adrenal volume.

CONCLUSION

The use of 3D printing associated with adrenal volumetry might be a useful tool for the surgeon when performing PA, enabling an estimation of the remnant gland volume.

Optimizing cerebrovascular surgical and endovascular procedures in children via personalized 3D printing

OBJECT Despite the availability of multiplanar imaging, understanding relational 3D anatomy for complex cerebrovascular lesions can be difficult. A 3D printed model allows for instantaneous visualization of lesional anatomy from all perspectives, with the added ability to simulate operative approaches with tactile feedback. The authors report their experience with customized 3D printed models of pediatric cerebrovascular lesions as an educational and clinical tool for patients, trainees, and physicians. METHODS Via an "in-house" 3D print service, magnetic resonance imaging (MRI) and computerized tomography (CT) studies of pediatric patients with arteriovenous malformations (AVMs) were processed with specialized software, and regions of interest were selected by the surgical/endovascular team. Multiple models for each patient were then printed on a 3D printer, with each construct designed to illustrate different aspects of the specific lesion. Intraoperative validation of model fidelity was performed using perioperative imaging, surgical filming, and post hoc analysis of models with intraoperative photography. RESULTS Four cases involving pediatric patients (ages 0-16 years) were studied for initial proof of principle. Three of the patients had AVMs and one had a vein of Galen malformation (VOGM). The VOGM was embolized successfully and the AVMs were resected without complication. In the AVM cases, intraprocedural imaging and photography were performed and verified millimeter-level fidelity of the models (n = 5, 98% concordance, range 94%-100% with average of < 2 mm variation in the largest AVM [6-cm diameter]). The use of 3D models was associated with a 30-minute reduction in operative time (12%) in 2 cases when they were compared with matched controls as a feasibility study. CONCLUSIONS Patient-specific 3D printed models of pediatric cerebrovascular conditions can be constructed with high fidelity. This proof-of-principle series demonstrates, for the first time, confirmation of model accuracy using intraprocedural assessment and potential benefit through shortened operative time.

Introducing a 3-dimensionally Printed, Tissue-Engineered Graft for Airway Reconstruction

Objective:

To use 3-dimensional (3D) printing and tissue engineering to create a graft for laryngotracheal reconstruction (LTR).

Study Design:

In vitro and in vivo pilot animal study.

Setting:

Large tertiary care academic medical center.

Subjects and Methods:

A 3D computer model of an anterior LTR graft was designed. That design was printed with polylactic acid on a commercially available 3D printer. The scaffolds were seeded with mature chondrocytes and collagen gel and cultured in vitro for up to 3 weeks. Scaffolds were evaluated in vitro for cell viability and proliferation. Anterior graft LTR was performed on 9 New Zealand white rabbits with the newly created scaffolds. Three animals were sacrificed at each time point (4, 8, and 12 weeks). The in vivo graft sites were assessed via bronchoscopy and histology.

Results:

The in vitro cell proliferation assay demonstrated initial viability of 87.5%. The cells proliferated during the study period, doubling over the first 7 days. Histology revealed that the cells retained their cartilaginous properties during the 21-day study period. In vivo testing showed that all animals survived for the duration of the study. Bronchoscopy revealed a well-mucosalized tracheal lumen with no evidence of scarring or granulation tissue. Histology indicated the presence of newly formed cartilage in the region where the graft was present.

Conclusions:

Our results indicate that it is possible to produce a custom-designed, 3D-printed, tissue-engineered graft for airway reconstruction.

Three-dimensional printing in surgery: a review of current surgical applications

BACKGROUND

Three-dimensional printing (3DP) is gaining increasing recognition as a technique that will transform the landscape of surgical practice. It allows for the rapid conversion of anatomic images into physical objects, which are being used across a variety of surgical specialties. It has been unclear which groups are leading the way in coming up with novel ways of using the technology and what specifically the technology is being used for. The aim of this article was to review the current applications of 3DP in modern surgical practice.

MATERIALS AND METHODS

An electronic search was carried out in MEDLINE, EMBASE, and PsycINFO for terms related to 3DP. These were then screened for relevance and practical applications of the technology in surgery.

RESULTS

Four hundred eighty-eight articles were initially found, and these were eventually narrowed down to 93 full-text articles. It was determined that there were three main areas in which the technology is being used to print: (1) anatomic models, (2) surgical instruments, and (3) implants and prostheses.

CONCLUSIONS

Different specialties are at different stages in the use of the technology. The costs involved with implementing the technology and time taken for printing are important factors to consider before widespread use. For the foreseeable future, this is an exciting and interesting technology with the capacity to radically change health care and revolutionize modern surgery.