3D multi-tissue printing for kidney transplantation

3D printing: a useful tool for safe clinical practice in children with complex vasculature

BACKGROUND

3D printing has been used in different medical contexts, although it is underutilised in paediatrics. We present the first use of 3D printing in the management of three paediatric patients with complex renovascular disease.

METHODS

Patient-specific 3D models were produced from conventional 2D imaging and manufactured using 3D polyjet printing technology. All three patients had different underlying pathologies, but all underwent multiple endovascular interventions (renal artery balloon angioplasty) prior to 3D printing and subsequent vascular surgery. The models were verified by an expert radiologist and then presented to the multidisciplinary team to aid with surgical planning.

RESULTS

Following evaluation of the 3D-printed models, all patients underwent successful uni/bilateral renal auto-transplants and aortic bypass surgery. The 3D models allowed more detailed preoperative discussions and more focused planning of surgical approach, therefore enhancing safer surgical planning. It influenced clinical decision-making and shortened general anaesthetic time. The families and the patients reported that they had a significantly improved understanding of the patient's condition and had more confidence in understanding proposed surgical intervention, thereby contributing to obtaining good-quality informed consent.

CONCLUSION

3D printing has a great potential to improve both surgical safety and decision-making as well as patient understanding in the field of paediatrics and may be considered in wider surgical areas.

Three-Dimensional Printing and Bioprinting in Renal Transplantation and Regenerative Medicine: Current Perspectives

For patients with end-stage kidney disease (ESKD), renal transplantation is the treatment of choice, constituting the most common solid organ transplantation. This study aims to provide a comprehensive review regarding the application of three-dimensional (3D) printing and bioprinting in renal transplantation and regenerative medicine. Specifically, we present studies where 3D-printed models were used in the training of surgeons through renal transplantation simulations, in patient education where patients acquire a higher understanding of their disease and the proposed operation, in the preoperative planning to facilitate decision-making, and in fabricating customized, tools and devices. Three-dimensional-printed models could transform how surgeons train by providing surgical rehearsal platforms across all surgical specialties, enabling training with tissue realism and anatomic precision. The use of 3D-printed models in renal transplantations has shown a positive impact on surgical outcomes, including the duration of the operation and the intraoperative blood loss. Regarding 3D bioprinting, the technique has shown promising results, especially in the field of microfluidic devices, with the development of tissue demonstrating proximal tubules, glomerulus, and tubuloinerstitium function, and in renal organoid development. Such models can be applied for renal disease modeling, drug development, and renal regenerative medicine.

The First Entirely 3D-Printed Training Model for Robot-assisted Kidney Transplantation: The RAKT Box

Background

Robot-assisted kidney transplantation (RAKT) is increasingly performed at selected referral institutions worldwide. However, simulation and proficiency-based progression training frameworks for RAKT are still lacking, making acquisition of the RAKT-specific skill set a critical unmet need for future RAKT surgeons.

Objective

To develop and test the RAKT Box, the first entirely 3D-printed, perfused, hyperaccuracy simulator for vascular anastomoses during RAKT.

Design setting and participants

The project was developed in a stepwise fashion by a multidisciplinary team including urologists and bioengineers via an iterative process over a 3-yr period (November 2019-November 2022) using an established methodology. The essential and time-sensitive steps of RAKT were selected by a team of RAKT experts and simulated using the RAKT Box according to the principles of the Vattituki-Medanta technique. The RAKT Box was tested in the operating theatre by an expert RAKT surgeon and independently by four trainees with heterogeneous expertise in robotic surgery and kidney transplantation.

Surgical procedure

Simulation of RAKT.

Measurements

Video recordings of the trainees' performance of vascular anastomoses using the RAKT Box were evaluated blind by a senior surgeon according to the Global Evaluative Assessment of Robotic Skills (GEARS) and Assessment of Robotic Console Skills (ARCS) tools.

Results and limitations

All participants successfully completed the training session, confirming the technical reliability of the RAKT Box simulator. Tangible differences were observed among the trainees in both anastomosis time and performance metrics. Key limitations of the RAKT Box include lack of simulation of the ureterovesical anastomosis and the need for a robotic platform, specific training instruments, and disposable 3D-printed vessels.

Conclusions

The RAKT Box is a reliable educational tool to train novice surgeons in the key steps of RAKT and may represent the first step toward the definition of a structured surgical curriculum in RAKT.

Patient summary

We describe the first entirely 3D-printed simulator that allows surgeons to test the key steps of robot-assisted kidney transplantation (RAKT) in a training environment before performing the procedure in patients. The simulator, called the RAKT Box, has been successfully tested by an expert surgeon and four trainees. The results confirm its reliability and potential as an educational tool for training of future RAKT surgeons.

Application of three-dimensional printing technology in renal diseases

Three-dimensional (3D) printing technology involves the application of digital models to create 3D objects. It is used in construction and manufacturing and has gradually spread to medical applications, such as implants, drug development, medical devices, prosthetic limbs, and in vitro models. The application of 3D printing has great prospects for development in orthopedics, maxillofacial plastic surgery, cardiovascular conditions, liver disease, and other fields. With in-depth research on 3D printing technology and the continuous update of printing materials, this technology also shows broad development prospects in renal medicine. In this paper, the author mainly summarizes the basic theory of 3D printing technology, its research progress, application status, and development prospect in renal diseases.

Three-Dimensional (3D) Printing in Cancer Therapy and Diagnostics: Current Status and Future Perspectives

Three-dimensional (3D) printing is a technique where the products are printed layer-by-layer via a series of cross-sectional slices with the exact deposition of different cell types and biomaterials based on computer-aided design software. Three-dimensional printing can be divided into several approaches, such as extrusion-based printing, laser-induced forward transfer-based printing systems, and so on. Bio-ink is a crucial tool necessary for the fabrication of the 3D construct of living tissue in order to mimic the native tissue/cells using 3D printing technology. The formation of 3D software helps in the development of novel drug delivery systems with drug screening potential, as well as 3D constructs of tumor models. Additionally, several complex structures of inner tissues like stroma and channels of different sizes are printed through 3D printing techniques. Three-dimensional printing technology could also be used to develop therapy training simulators for educational purposes so that learners can practice complex surgical procedures. The fabrication of implantable medical devices using 3D printing technology with less risk of infections is receiving increased attention recently. A Cancer-on-a-chip is a microfluidic device that recreates tumor physiology and allows for a continuous supply of nutrients or therapeutic compounds. In this review, based on the recent literature, we have discussed various printing methods for 3D printing and types of bio-inks, and provided information on how 3D printing plays a crucial role in cancer management.

Automatic Segmentation of Kidneys and Kidney Tumors: The KiTS19 International Challenge

Purpose: Clinicians rely on imaging features to calculate complexity of renal masses based on validated scoring systems. These scoring methods are labor-intensive and are subjected to interobserver variability. Artificial intelligence has been increasingly utilized by the medical community to solve such issues. However, developing reliable algorithms is usually time-consuming and costly. We created an international community-driven competition (KiTS19) to develop and identify the best system for automatic segmentation of kidneys and kidney tumors in contrast CT and report the results.

Methods: A training and test set of CT scans that was manually annotated by trained individuals were generated from consecutive patients undergoing renal surgery for whom demographic, clinical and outcome data were available. The KiTS19 Challenge was a machine learning competition hosted on grand-challenge.org in conjunction with an international conference. Teams were given 3 months to develop their algorithm using a full-annotated training set of images and an unannotated test set was released for 2 weeks from which average Sørensen-Dice coefficient between kidney and tumor regions were calculated across all 90 test cases.

Results: There were 100 valid submissions that were based on deep neural networks but there were differences in pre-processing strategies, architectural details, and training procedures. The winning team scored a 0.974 kidney Dice and a 0.851 tumor Dice resulting in 0.912 composite score. Automatic segmentation of the kidney by the participating teams performed comparably to expert manual segmentation but was less reliable when segmenting the tumor.

Conclusion: Rapid advancement in automated semantic segmentation of kidney lesions is possible with relatively high accuracy when the data is released publicly, and participation is incentivized. We hope that our findings will encourage further research that would enable the potential of adopting AI into the medical field.

Three-Dimensional Visualization With Virtual Reality Facilitates Complex Live Donor Renal Transplant

Background: Living donor renal transplant involves highly technical operations in both a healthy donor and a recipient with end-stage kidney disease. Contrast-enhanced computed tomography angiography (CTA) is used to assess critical donor anatomy, but its interpretation becomes increasingly difficult as renal anatomy becomes more complex. Case Report: A related donor was denied because of prohibitive anatomy seen on the pretransplant evaluation CTA. As the donor was highly motivated to donate, CTA DICOM images were segmented to create a 3-dimensional (3D) model that could be evaluated in an immersive and stereoscopic virtual reality (VR) environment. The donor's anatomy was found to be acceptable, and he was approved. Conclusion: In live donor nephrectomy candidates, 3D reconstruction and VR visualization can be used to facilitate appreciation of complex anatomy.

Three-Dimensional Printing for Cancer Applications: Research Landscape and Technologies

As a variety of novel technologies, 3D printing has been considerably applied in the field of health care, including cancer treatment. With its fast prototyping nature, 3D printing could transform basic oncology discoveries to clinical use quickly, speed up and even revolutionise the whole drug discovery and development process. This literature review provides insight into the up-to-date applications of 3D printing on cancer research and treatment, from fundamental research and drug discovery to drug development and clinical applications. These include 3D printing of anticancer pharmaceutics, 3D-bioprinted cancer cell models and customised nonbiological medical devices. Finally, the challenges of 3D printing for cancer applications are elaborated, and the future of 3D-printed medical applications is envisioned.

The Role of 3D-Printed Phantoms and Devices for Organ-specified Appliances in Urology

Urology is one of the fields that are always at the frontline of bringing scientific advancements into clinical practice, including 3D printing (3DP). This study aims to discuss and presents the current role of 3D-printed phantoms and devices for organ-specified applications in urology. The discussion started with a literature search regarding the two mentioned topics within PubMed, Embase, Scopus, and EBSCOhost databases. 3D-printed urological organ phantoms are reported for providing residents new insight regarding anatomical characteristics of organs, either normal or diseased, in a tangible manner. Furthermore, 3D-printed organ phantoms also helped urologists to prepare a pre-surgical planning strategy with detailed anatomical models of the diseased organs. In some centers, 3DP technology also contributed to developing specified devices for disease management. To date, urologists have been benefitted by 3D-printed phantoms and devices in the education and disease management of organs of in the genitourinary system, including kidney, bladder, prostate, ureter, urethra, penis, and adrenal. It is safe to say that 3DP technology can bring remarkable changes to daily urological practices.

Physicochemical parameters that underlie inkjet printing for medical applications

One of the most common types of 3D printing technologies is inkjet printing due to its numerous advantages, including low cost, programmability, high resolution, throughput, and speed. Inkjet printers are also capable of fabricating artificial tissues with physiological characteristics similar to those of living tissues. These artificial tissues are used for disease modeling, drug discovery, drug screening, and replacements for diseased or damaged tissues. This paper reviews recent advancements in one of the most common 3D printing technologies, inkjet dispensing. We briefly consider common printing techniques, including fused deposition modeling (FDM), stereolithography (STL), and inkjet printing. We briefly discuss various steps in inkjet printing, including droplet generation, droplet ejection, interaction of droplets on substrates, drying, and solidification. We also discuss various parameters that affect the printing process, including ink properties (e.g., viscosity and surface tension), physical parameters (e.g., internal diameter of printheads), and actuation mechanisms (e.g., piezoelectric actuation and thermal actuation). Through better understanding of common 3D printing technologies and the parameters that influence the printing processes, new types of artificial tissues, disease models, and structures for drug discovery and drug screening may be prepared. This review considers future directions in inkjet printing research that are focused on enhancing the resolution, printability, and uniformity of printed structures.

Whole Organ Engineering: Approaches, Challenges, and Future Directions

End-stage organ failure remains a leading cause of morbidity and mortality across the globe. The only curative treatment option currently available for patients diagnosed with end-stage organ failure is organ transplantation. However, due to a critical shortage of organs, only a fraction of these patients are able to receive a viable organ transplantation. Those patients fortunate enough to receive a transplant must then be subjected to a lifelong regimen of immunosuppressant drugs. The concept of whole organ engineering offers a promising alternative to organ transplantation that overcomes these limitations. Organ engineering is a discipline that merges developmental biology, anatomy, physiology, and cellular interactions with enabling technologies such as advanced biomaterials and biofabrication to create bioartificial organs that recapitulate native organs in vivo. There have been numerous developments in bioengineering of whole organs over the past two decades. Key technological advancements include (1) methods of whole organ decellularization and recellularization, (2) three-dimensional bioprinting, (3) advanced stem cell technologies, and (4) the ability to genetically modify tissues and cells. These advancements give hope that organ engineering will become a commercial reality in the next decade. In this review article, we describe the foundational principles of whole organ engineering, discuss key technological advances, and provide an overview of current limitations and future directions.