Three-dimensional printing creates models for surgical planning of aortic valve replacement after previous coronary bypass grafting

Advantages and disadvantages of 3-dimensional printing in surgery: A systematic review

BACKGROUND

Three-dimensional (3D) printing is becoming increasingly important in medicine and especially in surgery. The aim of the present work was to identify the advantages and disadvantages of 3D printing applied in surgery.

METHODS

We conducted a systematic review of articles on 3D printing applications in surgery published between 2005 and 2015 and identified using a PubMed and EMBASE search. Studies dealing with bioprinting, dentistry, and limb prosthesis or those not conducted in a hospital setting were excluded.

RESULTS

A total of 158 studies met the inclusion criteria. Three-dimensional printing was used to produce anatomic models (n = 113, 71.5%), surgical guides and templates (n = 40, 25.3%), implants (n = 15, 9.5%) and molds (n = 10, 6.3%), and primarily in maxillofacial (n = 79, 50.0%) and orthopedic (n = 39, 24.7%) operations. The main advantages reported were the possibilities for preoperative planning (n = 77, 48.7%), the accuracy of the process used (n = 53, 33.5%), and the time saved in the operating room (n = 52, 32.9%); 34 studies (21.5%) stressed that the accuracy was not satisfactory. The time needed to prepare the object (n = 31, 19.6%) and the additional costs (n = 30, 19.0%) were also seen as important limitations for routine use of 3D printing.

CONCLUSION

The additional cost and the time needed to produce devices by current 3D technology still limit its widespread use in hospitals. The development of guidelines to improve the reporting of experience with 3D printing in surgery is highly desirable.

Preoperative surgical simulation of laparoscopic adrenalectomy for neuroblastoma using a three-dimensional printed model based on preoperative CT images

BACKGROUND

Three-dimensional (3D) printed models based on computed tomography (CT) images facilitate the visualization of complex structures and are useful for understanding the surgical anatomy preoperatively. We developed a preoperative surgical simulation method using a 3D printed model based on CT images obtained prior to laparoscopic adrenalectomy for adrenal neuroblastomas (NBs).

MATERIALS AND METHODS

The multi-detector CT images were transferred to a 3D workstation, and 3D volume data were obtained by reconstructing the sections. A model was made with a 3D printer using acrylic ultraviolet curable resin. The adrenal tumor, kidney, renal vein and artery, inferior vena cava, aorta, and outer body were fabricated. The pneumoperitoneum, insertion of trocars, and laparoscopic view were all attainable in this model. We used this model for three cases with adrenal NB.

RESULTS

We used this model to discuss the port layout before the operation and to simulate the laparoscopic view and range of forceps movement. All three cases with NB were completely resected without any surgical complications.

CONCLUSIONS

The surgical simulation using 3D printed models based on preoperative CT images for adrenal NB was very useful for understanding the patient's surgical anatomy and for planning the surgical procedures, especially for determining the optimal port layout.

Antenatal Three-Dimensional Printing of Aberrant Facial Anatomy

Congenital airway obstruction poses a life-threatening challenge to the newborn. We present the first case of three-dimensional (3D) modeling and 3D printing of complex fetal maxillofacial anatomy after prenatal ultrasound indicated potential upper airway obstruction from a midline mass of the maxilla. Using fetal MRI and patient-specific computer-aided modeling, the craniofacial anatomy of the fetus was manufactured using a 3D printer. This model demonstrated the mass to be isolated to the upper lip and maxilla, suggesting the oral airway to be patent. The decision was made to deliver the infant without a planned ex utero intrapartum treatment procedure. The neonate was born with a protuberant cleft lip and palate deformity, without airway obstruction, as predicted by the patient-specific model. The delivery was uneventful, and the child was discharged without need for airway intervention. This case demonstrates that 3D modeling may improve prenatal evaluation of complex patient-specific fetal anatomy and facilitate the multidisciplinary approach to perinatal management of complex airway anomalies.

Applications of three-dimensional printing technology in the cardiovascular field

Three-dimensional (3-D) printing technology has rapidly developed in the last few decades. Meanwhile, the application of this technology has reached beyond the engineering field and expanded to almost all disciplines, including medicine. There has been much research on the medical applications of 3-D printing in neurosurgery, orthopedics, maxillofacial surgery, plastic surgery, tissue engineering, as well as other fields. Because of the complexity of the cardiovascular system, the application of this technology is limited and difficult, as compared to other disciplines, and thus there is much room for future development. Many of the difficulties associated with this technology must be overcome. Nonetheless, there is no doubt that 3-D printing technology will benefit patients with cardiovascular diseases in the near future.

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.

Emerging Applications of Bedside 3D Printing in Plastic Surgery

Modern imaging techniques are an essential component of preoperative planning in plastic and reconstructive surgery. However, conventional modalities, including three-dimensional (3D) reconstructions, are limited by their representation on 2D workstations. 3D printing, also known as rapid prototyping or additive manufacturing, was once the province of industry to fabricate models from a computer-aided design (CAD) in a layer-by-layer manner. The early adopters in clinical practice have embraced the medical imaging-guided 3D-printed biomodels for their ability to provide tactile feedback and a superior appreciation of visuospatial relationship between anatomical structures. With increasing accessibility, investigators are able to convert standard imaging data into a CAD file using various 3D reconstruction softwares and ultimately fabricate 3D models using 3D printing techniques, such as stereolithography, multijet modeling, selective laser sintering, binder jet technique, and fused deposition modeling. However, many clinicians have questioned whether the cost-to-benefit ratio justifies its ongoing use. The cost and size of 3D printers have rapidly decreased over the past decade in parallel with the expiration of key 3D printing patents. Significant improvements in clinical imaging and user-friendly 3D software have permitted computer-aided 3D modeling of anatomical structures and implants without outsourcing in many cases. These developments offer immense potential for the application of 3D printing at the bedside for a variety of clinical applications. In this review, existing uses of 3D printing in plastic surgery practice spanning the spectrum from templates for facial transplantation surgery through to the formation of bespoke craniofacial implants to optimize post-operative esthetics are described. Furthermore, we discuss the potential of 3D printing to become an essential office-based tool in plastic surgery to assist in preoperative planning, developing intraoperative guidance tools, teaching patients and surgical trainees, and producing patient-specific prosthetics in everyday surgical practice.

Three-dimensional liver model based on preoperative CT images as a tool to assist in surgical planning for hepatoblastoma in a child

The patient is a 3-year-old female diagnosed with PRETEXT IV hepatoblastoma (HB). Although the tumor was decreased after the neoadjuvant chemotherapy, HB still located at the porta hepatis. The patient underwent extended left lobectomy successfully after surgical simulation using three-dimensional (3D) printing liver model based on preoperative CT.

Current progress in tissue engineering of heart valves: multiscale problems, multiscale solutions

INTRODUCTION

Heart valve disease is an increasingly prevalent and clinically serious condition. There are no clinically effective biological diagnostics or treatment strategies. The only recourse available is replacement with a prosthetic valve, but the inability of these devices to grow or respond biologically to their environments necessitates multiple resizing surgeries and life-long coagulation treatment, especially in children. Tissue engineering has a unique opportunity to impact heart valve disease by providing a living valve conduit, capable of growth and biological integration.

AREAS COVERED

This review will cover current tissue engineering strategies in fabricating heart valves and their progress towards the clinic, including molded scaffolds using naturally derived or synthetic polymers, decellularization, electrospinning, 3D bioprinting, hybrid techniques, and in vivo engineering.

EXPERT OPINION

Whereas much progress has been made to create functional living heart valves, a clinically viable product is not yet realized. The next leap in engineered living heart valves will require a deeper understanding of how the natural multi-scale structural and biological heterogeneity of the tissue ensures its efficient function. Related, improved fabrication strategies must be developed that can replicate this de novo complexity, which is likely instructive for appropriate cell differentiation and remodeling whether seeded with autologous stem cells in vitro or endogenously recruited cells.

Three-dimensional printing to facilitate anatomic study, device development, simulation, and planning in thoracic surgery

BACKGROUND

The development and deployment of new technologies in additive 3-dimensional (3D) printing (ie, rapid prototyping and additive manufacturing) in conjunction with medical imaging techniques allow the creation of anatomic models based on patient data.

OBJECTIVE

To explore this rapidly evolving technology for possible use in care and research for patients undergoing thoracic surgery.

METHODS

Because of an active research project at our institution on regional lung chemotherapy, human pulmonary arteries (PAs) were chosen for this rapid prototyping project. Computed tomography (CT) and CT angiography in combination with segmentation techniques from 2 software packages were used for rapid generation and adjustment of the 3D polygon mesh and models reconstruction of the PAs. The reconstructed models were exported as stereolithographic data sets and further processed by trimming, smoothing, and wall extrusion.

RESULTS

Flexible 3D printed replicas of 10 patient PAs were created successfully with no print failures; however, 1 initial test print with a 1 mm mural thickness was too fragile so the whole group was printed with a 1.5 mm wall. The design process took 8 hours for each model (CT image to stereolithographic) and printing required 97 hours in aggregate. Useful differences in anatomy were defined by this method, such as the expected greater number of proximal branches on the left versus right (2.5 ± 1.1 vs 1.0 ± 0.0; P = .001).

CONCLUSIONS

Reconstructed models of pulmonary arteries using 3D rapid prototyping allow replication of sophisticated anatomical structures that can be used to facilitate anatomic study, surgical planning, and device development.

Three-dimensional printing in cardiac surgery and interventional cardiology: a single-centre experience

OBJECTIVES

In individual cases, routine preoperative imaging might not be sufficient for optimal planning of cardiovascular procedures. Three-dimensional printing (3D), a widely used technique to build life-like replicas of anatomical structures that has proven value in different medical disciplines, might overcome these shortcomings. However, data on 3D printing in cardiovascular medicine are limited to single reports. This stimulated us to present our single-centre experience with 3D printing models in cardiac surgery and interventional cardiology.

METHODS

Between the years 2006 and 2013, we fabricated 3D printing models using preoperative computed tomography or magnetic resonance imaging data in paediatric and adult cardiac surgery, as well as interventional cardiology. We present the 8 most representative cases.

RESULTS

The models were very helpful for perioperative planning and orientation, as well as simulation of procedures due to the exact and life-like illustration of the cardiovascular anatomy.

CONCLUSIONS

The fabrication of 3D printing models is feasible for perioperative planning and simulation in a variety of complex cases in paediatric and adult cardiac surgery, as well as in interventional cardiology. Further studies including more patients and providing more data are expected to demonstrate that the use of 3D printing may decrease morbidity and mortality of complex, non-routine procedures in cardiovascular medicine.

Experimental study of PLLA/INH slow release implant fabricated by three dimensional printing technique and drug release characteristics in vitro

Background

Local slow release implant provided long term and stable drug release in the lesion. The objective of this study was to fabricate biodegradable slow release INH/PLLA tablet via 3 dimensional printing technique (3DP) and to compare the drug release characteristics of three different structured tablets in vitro.

Methods

Three different drug delivery systems (columnar-shaped tablet (CST), doughnut-shaped tablet (DST) and multilayer doughnut-shaped tablet (MDST)) were manufactured by the three dimensional printing machine and isoniazid was loaded into the implant. Dynamic soaking method was used to study the drug release characteristics of the three implants. MTT cytotoxicity test and direct contact test were utilized to study the biocompatibility of the implant. The microstructures of the implants’ surfaces were observed with electron microscope.

Results

The PLLA powder in the tablet could be excellently combined through 3DP without disintegration. Electron microscope observations showed that INH distributed evenly on the surface of the tablet in a “nest-shaped” way, while the surface of the barrier layer in the multilayer doughnut shaped tablet was compact and did not contain INH. The concentration of INH in all of the three tablets were still higher than the effective bacteriostasis concentration (Isoniazid: 0.025 ~ 0.05 μg/ml) after 30 day’s release in vitro. All of the tablets showed initial burst release of the INH in the early period. Drug concentration of MDST became stable and had little fluctuation starting from the 6th day of the release. Drug concentration of DST and CST decreased gradually and the rate of decrease in concentration was faster in DST than CST. MTT cytotoxicity test and direct contact test indicated that the INH-PLLA tablet had low cytotoxicity and favorable biocompatibility.

Conclusions

Three dimensional printing technique was a reliable technique to fabricate complicated implants. Drug release pattern in MDST was the most stable among the three implants. It was an ideal drug delivery system for the antibiotics. Biocompatibility tests demonstrated that the INH-PLLA implant did not have cytotoxicity. The multilayer donut-shaped tablet provided a new constant slow release method after an initial burst for the topical application of the antibiotic.

Three-dimensional printing model of anomalous bronchi before surgery

Lung surgeries in patients with bronchial variations have rarely been reported. Here, we describe the case of a patient along with lung cancer with variant anatomy of the right upper lobe bronchus. This variation was evaluated by three-dimensional multi-detector computed tomography angiography with bronchography and a three-dimensional printing model using rapid prototyping. The variant anterior segment bronchus (S3) of the right upper lobe arising from the middle lobe bronchus was confirmed before surgery using the printing model, which helped to determine the extent of resection required and facilitated the understanding of the patient's anatomy during surgery. A thoracoscopic anterior segmentectomy and middle lobectomy were performed. The printing model was useful for detecting and evaluating the variant bronchi.

Surgical strategy for biventricular assist device implantation after previous coronary artery bypass grafting

In an aging population, numerous patients who underwent previous coronary artery bypass grafting (CABG) are presenting with end-stage ischemic cardiomyopathy. Although redo CABG and cardiological interventions are possible treatment options, orthotopic heart transplantation remains an ultimate option for these patients. However, there is high morbidity and mortality on the waiting list, and mechanical circulatory support is a life-saving concept [Hetzer 2006; Taylor 2009].We developed a simplified and safe technique for implantation of a biventricular assist device as a redo in complex patients after previous CABG and end-stage heart failure.

Evaluation of patients after coronary artery bypass grafting

Modern techniques for coronary artery bypass graft (CABG) are highly successful. Nevertheless, over time, grafts do fail and native coronary artery disease does progress. Follow-up of patients after CABG should focus on secondary prevention, including careful attention to all modifiable risk factors for cardiovascular disease. Routine stress testing with or without imaging is usually not necessary if the patient is asymptomatic and engaging in normal physical activities, including moderate exercise without difficulty. Stress testing with electrocardiographic monitoring alone or in conjunction with nuclear myocardial perfusion imaging or echocardiography is commonly used if a patient develops recurrent symptoms post-CABG or is at particular high risk for complications. Computed tomography coronary angiography is a new, very powerful, noninvasive technique that can directly visualize both CABG and the native coronary arteries. Computed tomography coronary angiography is complimentary to functional stress testing in that it provides anatomic information about graft patency and native coronary artery stenoses, but the functional significance of these findings may still require stress testing with nuclear or ultrasound imaging. Further technical improvements, both in surgical techniques and in imaging, and prospective multicenter trials, are needed to better define the best methods for following patients post-CABG.

The practical clinical value of three-dimensional models of complex congenitally malformed hearts

OBJECTIVE

Detailed 3-dimensional anatomic information is essential when planning strategies of surgical treatment for patients with complex congenitally malformed hearts. Current imaging techniques, however, do not always provide all the necessary anatomic information in a user-friendly fashion. We sought to assess the practical clinical value of realistic 3-dimensional models of complex congenitally malformed hearts.

METHODS

In 11 patients, aged from 0.8 to 27 years, all with complex congenitally malformed hearts, an unequivocal decision regarding the optimum surgical strategy had not been reached when using standard diagnostic tools. Therefore, we constructed 3-dimensional virtual computer and printed cast models of the heart on the basis of high-resolution whole-heart or cine magnetic resonance imaging or computed tomography. Anatomic descriptions were compared with intraoperative findings when surgery was performed.

RESULTS

Independently of age-related factors, images acquired in all patients using magnetic resonance imaging and computed tomography proved to be of sufficient quality for producing the models without major differences in the postprocessing and revealing the anatomy in an unequivocal 3-dimensional context. Examination of the models provided invaluable additional information that supported the surgical decision-making. The anatomy as shown in the models was confirmed during surgery. Biventricular corrective surgery was achieved in 5 patients, palliative surgery was achieved in 3 patients, and lack of suitable surgical options was confirmed in the remaining 3 patients.

CONCLUSION

Realistic 3-dimensional modeling of the heart provides a new means for the assessment of complex intracardiac anatomy. We expect this method to change current diagnostic approaches and facilitate preoperative planning.