3D-printed soft-tissue physical models of renal malignancies for individualized surgical simulation: a feasibility study

Three-dimensional visualization techniques improve surgical Decision Making of robotic-assisted partial nephrectomy

Background

Complete preoperative comprehension of the adjacent structures of the kidney and location of renal vessels is essential for robot-assisted partial nephrectomy (RAPN). The effectiveness of three-dimensional (3D) visualization techniques in improving perioperative outcomes of RAPN has been inconsistent and has not been reported in Northeastern China.

Methods

In this cohort study, we reviewed patients with renal tumours who underwent RAPN between April 2019 and April 2024. Three-dimensional visualization models were reconstructed to evaluate resectability parameters, including vascular variations, collection system infiltration, and lymphatic involvement. Subsequently, a meta-analysis combining previous studies utilising 3D visualization techniques for partial nephrectomy was conducted.

Results

Of the 324 patients in the cohort, 147 were preoperatively evaluated using the 3D technology. Group 3D had significantly less estimated blood loss (P < 0.001) and a shorter operative time (P = 0.016) than in group No 3D. We also found that the rates of intraoperative ultrasound use (P = 0.015), intraoperative complications (P = 0.007), intraoperative transfusions (P = 0.007), and postoperative Clavien complications (P < 0.001) in group 3D were significantly lower than in group No 3D. The above findings were consistent in the subgroup with R.E.N.A.L. ≥ 8 points partly. Furthermore, a meta-analysis identified 11 studies that included 1522 patients who underwent RAPN. Use of 3D visualization technology resulted in decreased 55 % risk of opening the collecting system (Risk Ratio [RR] = 0.45[0.22-0.92], P = 0.030) and 79 % incidence of conversion to radical nephrectomy (RR = 0.21[0.08-0.57], P = 0.002). The RAPN group assisted by 3D visualization techniques showed an 81 % reduction in the risk of blood transfusion than in the control group (RR = 0.19[0.08-0.44], P < 0.001).

Conclusions

The application of 3D technology in RAPN appears to be superior for improving precise tumour removal and reducing adverse perioperative outcomes and should be considered for wide use in clinical practice.

Current Standards for Training in Robot-assisted Surgery and Endourology: A Systematic Review

BACKGROUND AND OBJECTIVE

Different training programs have been developed to improve trainee outcomes in urology. However, evidence on the optimal training methodology is sparse. Our aim was to provide a comprehensive description of the training programs available for urological robotic surgery and endourology, assess their validity, and highlight the fundamental elements of future training pathways.

METHODS

We systematically reviewed the literature using PubMed/Medline, Embase, and Web of Science databases. The validity of each training model was assessed. The methodological quality of studies on metrics and curricula was graded using the MERSQI scale. The level of evidence (LoE) and level of recommendation for surgical curricula were awarded using the educational Oxford Centre for Evidence-Based Medicine classification.

KEY FINDINGS AND LIMITATIONS

A total of 75 studies were identified. Many simulators have been developed to aid trainees in mastering skills required for both robotic and endourology procedures, but only four demonstrated predictive validity. For assessment of trainee proficiency, we identified 18 in robotics training and six in endourology training; however, the majority are Likert-type scales. Although proficiency-based progression (PBP) curricula demonstrated superior outcomes to traditional training in preclinical settings, only four of six (67%) in robotics and three of nine (33%) in endourology are PBP-based. Among these, the Fundamentals of Robotic Surgery and the SIMULATE curricula have the highest LoE (level 1b). The lack of a quantitative synthesis is the main limitation of our study.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Training curricula that integrate simulators and PBP methodology have been introduced to standardize trainee outcomes in robotics and endourology. However, evidence regarding their educational impact remains restricted to preclinical studies. Efforts should be made to expand these training programs to different surgical procedures and assess their clinical impact.

Practical applications of three-dimensional printing for process improvement in the cytopathology laboratory

With the increased availability of three-dimensional (3D) printers, innovative teaching and training materials have been created in medical fields. For pathology, the use of 3D printing has been largely limited to anatomic representations of disease processes or the development of supplies during the coronavirus disease 2019 pandemic. Herein, an institution's 3D printing laboratory and staff with expertise in additive manufacturing illustrate how this can address design issues in cytopathology specimen collection and processing. The authors' institutional 3D printing laboratory, along with students and trainees, used computer-aided design and 3D printers to iterate on design, create prototypes, and generate final usable materials using additive manufacturing. The program Microsoft Forms was used to solicit qualitative and quantitative feedback. The 3D-printed models were created to assist with cytopreparation, rapid on-site evaluation, and storage of materials in the preanalytical phase of processing. These parts provided better organization of materials for cytology specimen collection and staining, in addition to optimizing storage of specimens with multiple sized containers to optimize patient safety. The apparatus also allowed liquids to be stabilized in transport and removed faster at the time of rapid on-site evaluation. Rectangular boxes were also created to optimally organize all components of a specimen in cytopreparation to simplify and expedite the processes of accessioning and processing, which can minimize errors. These practical applications of 3D printing in the cytopathology laboratory demonstrate the utility of the design and printing process on improving aspects of the workflow in cytopathology laboratories to maximize efficiency, organization, and patient safety.

Development of a master-slave 3D printed robotic surgical finger with haptic feedback

Robotic surgery started nearly 30 years ago. It has achieved telepresence and the performance of repetitive, precise, and accurate tasks. The "master-slave" robotic system allows control of manipulators by surgeon at distant site. Robotic surgical fingers were developed to allow surgeons to move them with accuracy through sensors fixed on surgeon's hand. Also, haptic sensors were developed to allow transmission of sensation from robotic finger to surgeon's finger. A complete system of a, 3D printed by a stereolithography (SLA) 3D printer, robotic surgical finger with haptic feedback system is proposed. The developed system includes a master glove that controls the motion of a 3DOF robotic slave finger while getting haptic feedback of force/pressure exerted on it. The precise control of the slave robotic finger was achieved by applying a Proportional Integral and Derivative (PID), fast and robust, control algorithm using an Arduino based hardware and software module. The individual joint angles, metacarpophalangeal joint (MCP) and proximal interphalangeal joint (PIP), and wrist were measured using rotatory and inertial sensors respectively. The degree of movement for MCP, PIP, and Wrist joints were measured to be 0-86°, 0-71°, and 0-89° respectively. Motion to the robotic finger is mimicked by a glove motion requiring minimal learning curve for the device. The collected data for the slave motion is in good agreement with the master-glove motion data. The vibro-tactile haptic feedback system was developed to distinguish between three different materials to mimic human flesh, tumor, and bone. The master-slave system using robotic surgical finger with good simultaneous movement to surgeon's finger and good haptic sensation will provide the surgeon with the opportunity to perform finger dissection in laparoscopic and robotic surgery, as it used to be in open surgery. 3D bio printing will make this process even cheaper with the added advantage of making surgical tools locally according to the need of the surgery. An ongoing work is to develop silicone based 8 mm robotic surgical finger with multiple type haptic feedback.

Patient-specific simulations and navigation systems for partial nephrectomy

Partial nephrectomy (PN) is the standard treatment for T1 renal cell carcinoma. PN is affected more by surgical variations and requires greater surgical experience than radical nephrectomy. Patient-specific simulations and navigation systems may help to reduce the surgical experience required for PN. Recent advances in three-dimensional (3D) virtual reality (VR) imaging and 3D printing technology have allowed accurate patient-specific simulations and navigation systems. We reviewed previous studies about patient-specific simulations and navigation systems for PN. Recently, image reconstruction technology has developed, and commercial software that converts two-dimensional images into 3D images has become available. Many urologists are now able to view 3DVR images when preparing for PN. Surgical simulations based on 3DVR images can change surgical plans and improve surgical outcomes, and are useful during patient consultations. Patient-specific simulators that are capable of simulating surgical procedures, the gold-standard form of patient-specific simulations, have also been reported. Besides VR, 3D printing is also useful for understanding patient-specific information. Some studies have reported simulation and navigation systems for PN based on solid 3D models. Patient-specific simulations are a form of preoperative preparation, whereas patient-specific navigation is used intraoperatively. Navigation-assisted PN procedures using 3DVR images have become increasingly common, especially in robotic surgery. Some studies found that these systems produced improvements in surgical outcomes. Once its accuracy has been confirmed, it is hoped that this technology will spread further and become more generalized.

Three-dimensional Virtual Models of the Kidney with Colored Perfusion Regions: A New Algorithm-based Tool for Optimizing the Clamping Strategy During Robot-assisted Partial Nephrectomy

BACKGROUND

An empirical selective clamping strategy based on the direction of the arterial branches can lead to failures during partial nephrectomy, even when assisted by three-dimensional virtual models (3DVMs).

OBJECTIVE

To develop and test new 3DVMs that include kidney perfusion regions and evaluate their intraoperative accuracy in guiding selective clamping and their impact on postoperative renal function.

DESIGN, SETTING, AND PARTICIPANTS

For patients with a kidney suitable for nephron-sparing surgery, 3DVMs were supplemented with a Voronoi diagram, a Euclidean distance-based mathematical tool, to calculate vascular-dominant regions the kidney.

SURGICAL PROCEDURE

Robot-assisted partial nephrectomy guided by perfusion-region (PR)-3DVMs.

MEASUREMENTS

All anatomic information given by the PR-3DVMs was collected. Selective or superselective clamping was planned and performed intraoperatively when feasible under 3DVM assistance. Changes in split renal function (SRF) and estimated renal plasmatic flow (ERPF) were evaluated for 51 patients who underwent baseline and 3-mo postoperative renal scintigraphy.

RESULTS AND LIMITATIONS

A total of 103 patients were prospectively enrolled. The median number of kidney and tumor perfusion regions were 8 (interquartile range [IQR] 7-10) and 3 (IQR 2-3), respectively. A clampless, selective clamping, and global clamping strategy was applied in eight (7.8%), 79 (76.6%), and 16 (15.5%) cases, respectively, with no differences between planning and surgery in terms of the number or order of arteries clamped or the perfusion regions that underwent ischemia. Among the 51 patients who underwent renal scintigraphy, the mean SRF decreased by 11.3%, 7.7%, and 1.7% after global, selective, and superselective clamping, respectively (p = 0.004). Similar results were obtained for ERPF (18.9%, 9.9%, and 6.0%; p = 0.02). The main limitation is the need for a bioengineer to manually refine the 3DVMs.

CONCLUSIONS

Use of mathematical algorithms for 3DVMs allows precise estimation of kidney perfusion regions to maximize the efficacy of selective clamping and minimize renal function impairment.

PATIENT SUMMARY

Three-dimensional models that include regions of blood flow to the kidney can be used to guide clamping of blood vessels when part of the kidney is being surgically removed. More limited clamping can reduce damage to the remaining portion of the kidney and result in better recovery of kidney function after surgery.

Three-Dimensional Customized Imaging Reconstruction for Urological Surgery: Diffusion and Role in Real-Life Practice from an International Survey

Despite the arising interest in three-dimensional (3D) reconstruction models from 2D imaging, their diffusion and perception among urologists have been scarcely explored. The aim of the study is to report the results of an international survey investigating the use of such tools among urologists of different backgrounds and origins. Beyond demographics, the survey explored the degree to which 3D models are perceived to improve surgical outcomes, the procedures mostly making use of them, the settings in which those tools are mostly applied, the surgical steps benefiting from 3D reconstructions and future perspectives of improvement. One hundred responders fully completed the survey. All levels of expertise were allowed; more than half (53%) were first surgeons, and 59% had already completed their training. Their main application was partial nephrectomy (85%), followed by radical nephrectomy and radical prostatectomy. Three-dimensional models are mostly used for preoperative planning (75%), intraoperative consultation and tailoring. More than half recognized that 3D models may highly improve surgical outcomes. Despite their recognized usefulness, 77% of responders use 3D models in less than 25% of their major operations due to costs or the extra time taken to perform the reconstruction. Technical improvements and a higher availability of the 3D models will further increase their role in surgical and clinical daily practice.

Application effect of head-mounted mixed reality device combined with 3D printing model in neurosurgery ventricular and hematoma puncture training

BACKGROUND

The purpose of this study was to explore the applicability of application effect of head-mounted mixed reality (MR) equipment combined with a three-dimensional (3D) printed model in neurosurgical ventricular and haematoma puncture training.

METHODS

Digital Imaging and Communications in Medicine (DICOM) format image data of two patients with common neurosurgical diseases (hydrocephalus and basal ganglia haemorrhage) were imported into 3D Slicer software for 3D reconstruction, saved, and printed using 3D printing to produce a 1:1-sized head model with real person characteristics. The required model (brain ventricle, haematoma, puncture path, etc.) was constructed and imported into the head-mounted MR device, HoloLens, and a risk-free, visual, and repeatable system was designed for the training of junior physicians. A total of 16 junior physicians who studied under this specialty from September 2020 to March 2022 were selected as the research participants, and the applicability of the equipment and model during training was evaluated with assessment score sheets and questionnaires after training.

RESULTS

According to results of the assessment and questionnaire, the doctors trained by this system are more familiar with the localization of the lateral anterior ventricle horn puncture and the common endoscopic surgery for basal ganglia haemorrhage, as well as more confident in the mastery of these two operations than the traditional training methods.

CONCLUSIONS

The use of head-mounted MR equipment combined with 3D printing models can provide an ideal platform for the operation training of young doctors. Through holographic images created from the combination of virtual and real images, operators can be better immersed in the operation process and deepen their understanding of the operation and related anatomical structures. The 3D printed model can be repeatedly reproduced so that doctors can master the technology, learn from mistakes, better achieve the purpose of teaching and training, and improve the effect of training.

Artificial Intelligence-Based Hyper Accuracy Three-Dimensional (HA3D®) Models in Surgical Planning of Challenging Robotic Nephron-Sparing Surgery: A Case Report and Snapshot of the State-of-the-Art with Possible Future Implications

Recently, 3D models (3DM) gained popularity in urology, especially in nephron-sparing interventions (NSI). Up to now, the application of artificial intelligence (AI) techniques alone does not allow us to obtain a 3DM adequate to plan a robot-assisted partial nephrectomy (RAPN). Integration of AI with computer vision algorithms seems promising as it allows to speed up the process. Herein, we present a 3DM realized with the integration of AI and a computer vision approach (CVA), displaying the utility of AI-based Hyper Accuracy Three-dimensional (HA3D^®) models in preoperative planning and intraoperative decision-making process of challenging robotic NSI. A 54-year-old Caucasian female with no past medical history was referred to the urologist for incidental detection of the right renal mass. Preoperative contrast-enhanced abdominal CT confirmed a 35 × 25 mm lesion on the anterior surface of the upper pole (PADUA 7), with no signs of distant metastasis. CT images in DICOM format were processed to obtain a HA3D^® model. RAPN was performed using Da Vinci Xi surgical system in a three-arm configuration. The enucleation strategy was achieved after selective clamping of the tumor-feeding artery. Overall operative time was 85 min (14 min of warm ischemia time). No intra-, peri- and post-operative complications were recorded. Histopathological examination revealed a ccRCC (stage pT1aNxMx). AI is breaking new ground in medical image analysis panorama, with enormous potential in organ/tissue classification and segmentation, thus obtaining 3DM automatically and repetitively. Realized with the integration of AI and CVA, the results of our 3DM were accurate as demonstrated during NSI, proving the potentialities of this approach for HA3D^® models' reconstruction.

Impact of 3D printed models on quantitative surgical outcomes for patients undergoing robotic-assisted radical prostatectomy: a cohort study

BACKGROUND

Three-dimensional (3D) printed anatomic models can facilitate presurgical planning by providing surgeons with detailed knowledge of the exact location of pertinent anatomical structures. Although 3D printed anatomic models have been shown to be useful for pre-operative planning, few studies have demonstrated how these models can influence quantitative surgical metrics.

OBJECTIVE

To prospectively assess whether patient-specific 3D printed prostate cancer models can improve quantitative surgical metrics in patients undergoing robotic-assisted radical prostatectomy (RARP).

METHODS

Patients with MRI-visible prostate cancer (PI-RADS V2 ≥ 3) scheduled to undergo RARP were prospectively enrolled in our IRB approved study (n = 82). Quantitative surgical metrics included the rate of positive surgical margins (PSMs), operative times, and blood loss. A qualitative Likert scale survey to assess understanding of anatomy and confidence regarding surgical approach was also implemented.

RESULTS

The rate of PSMs was lower for the 3D printed model group (8.11%) compared to that with imaging only (28.6%), p = 0.128. The 3D printed model group had a 9-min reduction in operating time (213 ± 42 min vs. 222 ± 47 min) and a 5 mL reduction in average blood loss (227 ± 148 mL vs. 232 ± 114 mL). Surgeon anatomical understanding and confidence improved after reviewing the 3D printed models (3.60 ± 0.74 to 4.20 ± 0.56, p = 0.62 and 3.86 ± 0.53 to 4.20 ± 0.56, p = 0.22).

CONCLUSIONS

3D printed prostate cancer models can positively impact quantitative patient outcomes such as PSMs, operative times, and blood loss in patients undergoing RARP.

Simulation-based education in urology - an update

Over the past 30 years surgical training, including urology training, has changed from the Halstedian apprenticeship-based model to a competency-based one. Simulation-based education (SBE) is an effective, competency-based method for acquiring both technical and non-technical surgical skills and has rapidly become an essential component of urological education. This article introduces the key learning theory underpinning surgical education and SBE, discussing the educational concepts of mastery learning, deliberate practice, feedback, fidelity and assessment. These concepts are fundamental aspects of urological education, thus requiring clinical educators to have a detailed understanding of their impact on learning to assist trainees to acquire surgical skills. The article will then address in detail the current and emerging simulation modalities used in urological education, with specific urological examples provided. These modalities are part-task trainers and 3D-printed models for open surgery, laparoscopic bench and virtual reality trainers, robotic surgery simulation, simulated patients and roleplay, scenario-based simulation, hybrid simulation, distributed simulation and digital simulation. This article will particularly focus on recent advancements in several emerging simulation modalities that are being applied in urology training such as operable 3D-printed models, robotic surgery simulation and online simulation. The implementation of simulation into training programmes and our recommendations for the future direction of urological simulation will also be discussed.

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 Model-assisted Minimally Invasive Partial Nephrectomy: A Systematic Review with Meta-analysis of Comparative Studies

CONTEXT

Use of three-dimensional (3D) guidance for nephron-sparing surgery (NSS) has increased in popularity, especially for laparoscopic and robotic approaches. Different 3D visualization modalities have been developed as promising new tools for surgical planning and intraoperative navigation.

OBJECTIVES

To summarize and evaluate the impact of 3D models on minimally invasive NSS in terms of perioperative, functional, and oncological outcomes.

EVIDENCE ACQUISITION

A systematic literature search was conducted in December 2021 using the Medline (PubMed), Embase (Ovid), Scopus, and Web of Science databases. The protocol was registered on PROSPERO (CRD42022300948). The search strategy used the PICOS (Population, Intervention, Comparison, Outcome, Study design) criteria and article selection was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The risk of bias and the quality of the articles included were assessed. A dedicated data extraction form was used to collect the data of interest. Meta-analysis was performed using the Mantel-Haenszel method for binary outcomes, with results summarized as the odds ratio (OR), and the inverse variance method for continuous data, with results reported as the mean difference (MD). All effect estimates are reported with the 95% confidence interval (CI) and p ≤ 0.05 was considered statistically significant. All analyses were performed using R software and the meta package.

EVIDENCE SYNTHESIS

The initial electronic search identified 450 papers, of which 17 met the inclusion criteria and were included in the analysis. Use of 3D technology led to a significant reduction in the global ischemia rate (OR 0.22, 95% CI 0.07-0.76; p = 0.02) and facilitated more frequent enucleation (OR 2.54, 95% CI 1.36-4.74; p < 0.01) and less frequent opening of the collecting system (OR 0.36, 95% CI 0.15-0.89; p = 0.03) and was associated with less blood loss (MD 23.1 ml, 95% CI 31.8-14.4; p < 0.01). 3D guidance for NSS was associated with a significant reduction in the transfusion rate (OR 0.20, 95% CI 0.07-0.56; p < 0.01). There were no significant differences in rates of conversion to radical nephrectomy, minor and major complications, change in glomerular filtration rate, or surgical margins (all p > 0.05).

CONCLUSIONS

3D guidance for NSS is associated with lower rates of detriment and surgical injury to the kidney. Specifically, a lower amount of nontumor renal parenchyma is exposed to ischemia or sacrificed during resection, and opening of the collecting system is less frequent. However, use of 3D technology does not lead to significant improvements in oncological or functional outcomes.

PATIENT SUMMARY

We reviewed the use of three-dimensional tools for minimally invasive surgery for partial removal of the kidney in patients with kidney cancer. The evidence suggests that these tools have benefits during surgery, but do not lead to significant improvements in cancer control or functional outcomes for patients.

Systematic Review of Comparative Studies of 3D Models for Preoperative Planning in Minimally Invasive Partial Nephrectomy

Background: The employment of 3-dimensional (3D) virtual models of the organs and tumors, obtained from conventional 2-dimensional (2D) imaging (i.e. computed tomography scan and magnetic resonance imaging) have already demonstrated an outstanding potential in urology, especially in renal surgery. Objectives: The aim of this systematic review is to provide an updated focus on the results obtained from the preoperative employment of 3D virtual imaging reconstructions in nephron sparing oncological surgery. Methods: A systematic literature search was conducted in April 2022 using Medline (via PubMed), Embase (via Ovid), Scopus, and Web of Science. The search strategy used PICO criteria and article selection was conducted in accordance with the PRISMA guidelines. The risk of bias and the quality of the articles included were assessed. A dedicated data extraction form was used to collect the data of interest. Results: The initial electronic search identified 471 papers, of which 13 ultimately met the inclusion criteria and were included in the review. 11 studies reported outcomes of virtual models, 2 studies focused on printed 3D models. In these studies, the application of 3D models for preoperative planning has been reported to increase the selective clamping rate and reducing the opening of collecting system, blood loss and loss of renal function. Conclusions: 3D virtual models seem to provide some surgical benefits for preoperative planning especially for complex renal masses. In the next future the continuous evolution of this technology may further increase its field of application and its potential clinical benefit.

The use of individualized 3D-printed models on trainee and patient education, and surgical planning for robotic partial nephrectomies

3D printing is a growing tool in surgical education to visualize and teach complex procedures. Previous studies demonstrating the usefulness of 3D models as teaching tools for partial nephrectomy used highly detailed models costing between $250 and 1000. We aimed to create thorough, inexpensive 3D models to accelerate learning for trainees and increase health literacy in patients. Patient-specific, cost-effective ($30-50) 3D models of the affected urologic structures were created using pre-operative imaging of 40 patients undergoing partial nephrectomy at Thomas Jefferson University Hospital (TJUH) between July 2020 and May 2021. Patients undergoing surgery filled out a survey before and after seeing the model to assess patient understanding of their kidney, pathophysiology, surgical procedure, and risks of surgery. Three urological residents, one fellow, and six attendings filled out separate surveys to assess their surgical plan and confidence before and after seeing the model. In a third survey, they ranked how much the model helped their comprehension and confidence during surgery. Patient understanding of all four subjects significantly improved after seeing the 3D model (P < 0.001). The urology residents (P < 0.001) and fellow (P < 0.001) reported significantly increased self-confidence after interacting with the model. Attending surgeon confidence increased significantly after seeing the 3D model (P < 0.01) as well. Cost-effective 3D models are effective learning tools and assist with the evaluation of patients presenting with renal masses, and increase patient, resident, and fellow understanding in partial nephrectomies. Further research should continue to explore the utility of inexpensive models in other urologic procedures.

New imaging technologies for robotic kidney cancer surgery

Objective

Kidney cancers account for approximately 2% of all newly diagnosed cancer in 2020. Among the primary treatment options for kidney cancer, urologist may choose between radical or partial nephrectomy, or ablative therapies. Nowadays, robotic-assisted partial nephrectomy (RAPN) for the management of renal cancers has gained popularity, up to being considered the gold standard. However, RAPN is a challenging procedure with a steep learning curve.

Methods

In this narrative review, different imaging technologies used to guide and aid RAPN are discussed.

Results

Three-dimensional visualization technology has been extensively discussed in RAPN, showing its value in enhancing robotic-surgery training, patient counseling, surgical planning, and intraoperative guidance. Intraoperative imaging technologies such as intracorporeal ultrasound, near-infrared fluorescent imaging, and intraoperative pathological examination can also be used to improve the outcomes following RAPN. Finally, artificial intelligence may play a role in the field of RAPN soon.

Conclusion

RAPN is a complex surgery; however, many imaging technologies may play an important role in facilitating it.

Three-Dimensional Physical Model in Urologic Cancer

Three-dimensional (3D) printing, as an evolving technology, enables the creation of patient-specific physical models with high precision; thus, it is widely used in various clinical practices, especially urologic cancer. There is an increasing need to clarify the contribution of 3D printing in the practice of urological cancer in order to identify various applications and improve understanding its benefits and challenges in clinical practice. Researches have focused on the use of 3D-printed models in patient and trainee education, surgical simulation, as well as surgical planning and guidance. This mini review will present the most recently published studies on the topic, including the applications of 3D-printed models, feasibility of performed procedures, possible simulated organs, application outcomes, and challenges involved in urologic cancer, to provide potential directions for future research.

Anatomical Engineering and 3D Printing for Surgery and Medical Devices: International Review and Future Exponential Innovations

Three-dimensional printing (3DP) has recently gained importance in the medical industry, especially in surgical specialties. It uses different techniques and materials based on patients' needs, which allows bioprofessionals to design and develop unique pieces using medical imaging provided by computed tomography (CT) and magnetic resonance imaging (MRI). Therefore, the Department of Biology and Medicine and the Department of Physics and Engineering, at the Bioastronautics and Space Mechatronics Research Group, have managed and supervised an international cooperation study, in order to present a general review of the innovative surgical applications, focused on anatomical systems, such as the nervous and craniofacial system, cardiovascular system, digestive system, genitourinary system, and musculoskeletal system. Finally, the integration with augmented, mixed, virtual reality is analyzed to show the advantages of personalized treatments, taking into account the improvements for preoperative, intraoperative planning, and medical training. Also, this article explores the creation of devices and tools for space surgery to get better outcomes under changing gravity conditions.

The Role of 3D Printing in Planning Complex Medical Procedures and Training of Medical Professionals-Cross-Sectional Multispecialty Review

Medicine is a rapidly-evolving discipline, with progress picking up pace with each passing decade. This constant evolution results in the introduction of new tools and methods, which in turn occasionally leads to paradigm shifts across the affected medical fields. The following review attempts to showcase how 3D printing has begun to reshape and improve processes across various medical specialties and where it has the potential to make a significant impact. The current state-of-the-art, as well as real-life clinical applications of 3D printing, are reflected in the perspectives of specialists practicing in the selected disciplines, with a focus on pre-procedural planning, simulation (rehearsal) of non-routine procedures, and on medical education and training. A review of the latest multidisciplinary literature on the subject offers a general summary of the advances enabled by 3D printing. Numerous advantages and applications were found, such as gaining better insight into patient-specific anatomy, better pre-operative planning, mock simulated surgeries, simulation-based training and education, development of surgical guides and other tools, patient-specific implants, bioprinted organs or structures, and counseling of patients. It was evident that pre-procedural planning and rehearsing of unusual or difficult procedures and training of medical professionals in these procedures are extremely useful and transformative.

Deep Learning Plus Three-Dimensional Printing in the Management of Giant (>15 cm) Sporadic Renal Angiomyolipoma: An Initial Report

Objective

To evaluate the feasibility and effectivity of deep learning (DL) plus three-dimensional (3D) printing in the management of giant sporadic renal angiomyolipoma (RAML).

Methods

The medical records of patients with giant (>15 cm) RAML were retrospectively reviewed from January 2011 to December 2020. 3D visualized and printed kidney models were performed by DL algorithms and 3D printing technology, respectively. Patient demographics and intra- and postoperative outcomes were compared between those with 3D-assisted surgery (3D group) or routine ones (control group).

Results

Among 372 sporadic RAML patients, 31 with giant ones were eligible for analysis. The median age was 40.6 (18-70) years old, and the median tumor size was 18.2 (15-28) cm. Seventeen of 31 (54.8%) had a surgical kidney removal. Overall, 11 underwent 3D-assisted surgeries and 20 underwent routine ones. A significant higher success rate of partial nephrectomy (PN) was noted in the 3D group (72.7% vs. 30.0%). Patients in the 3D group presented a lower reduction in renal function but experienced a longer operation time, a greater estimated blood loss, and a higher postoperative morbidity. Subgroup analysis was conducted between patients undergoing PN with or without 3D assistance. Despite no significant difference, patients with 3D-assisted PN had a slightly larger tumor size and higher nephrectomy score, possibly contributing to a relatively higher rate of complications. However, 3D-assisted PN lead to a shorter warm ischemia time and a lower renal function loss without significant difference. Another subgroup analysis between patients under 3D-assisted PN or 3D-assisted RN showed no statistically significant difference. However, the nearness of tumor to the second branch of renal artery was relatively shorter in 3D-assisted PN subgroup than that in 3D-assisted RN subgroup, and the difference between them was close to significant.

Conclusions

3D visualized and printed kidney models appear to be additional tools to assist operational management and avoid a high rate of kidney removal for giant sporadic RAMLs.

3D Printing of Physical Organ Models: Recent Developments and Challenges

Physical organ models are the objects that replicate the patient-specific anatomy and have played important roles in modern medical diagnosis and disease treatment. 3D printing, as a powerful multi-function manufacturing technology, breaks the limitations of traditional methods and provides a great potential for manufacturing organ models. However, the clinical application of organ model is still in small scale, facing the challenges including high cost, poor mimicking performance and insufficient accuracy. In this review, the mainstream 3D printing technologies are introduced, and the existing manufacturing methods are divided into "directly printing" and "indirectly printing", with an emphasis on choosing suitable techniques and materials. This review also summarizes the ideas to address these challenges and focuses on three points: 1) what are the characteristics and requirements of organ models in different application scenarios, 2) how to choose the suitable 3D printing methods and materials according to different application categories, and 3) how to reduce the cost of organ models and make the process simple and convenient. Moreover, the state-of-the-art in organ models are summarized and the contribution of 3D printed organ models to various surgical procedures is highlighted. Finally, current limitations, evaluation criteria and future perspectives for this emerging area are discussed.

New Technologies for Kidney Surgery Planning 3D, Impression, Augmented Reality 3D, Reconstruction: Current Realities and Expectations

Purpose of review

We aim to summarize the current state of art about 3D applications in urology focusing on kidney surgeries. In addition we aim to provide a snapshot about future perspective of intraoperative applications of augmented reality (AR).

Recent findings

A variety of applications in different fields have been proposed. Many applications concern current realities and 3D reconstruction, while some others are about future perspective. The majority of recent studies have focused their attention on preoperative surgical planning, patient education, surgical training, and AR.

Summary

The disposability of 3D models in healthcare scenarios might improve surgical outcomes, learning curves of novice surgeons and residents, as well as patients’ understanding and compliance, allowing a more shared surgical decision-making.

Development and Validation of a Virtual Reality Haptic Femoral Nailing Simulator

OBJECTIVE

To create a virtual reality (VR) femoral nailing simulator combining haptics and image intensifier functionality and then carry out validation studies to assess its educational value.

DESIGN

The simulator consisted of a 3D virtual environment, a haptic device and 3D printed drill handle and a VR headset. The environment was created using a video game development engine, interfaced with plugins to allow haptic feedback and image intensifier functionality. Two tasks were created within the simulator as part of an antegrade femoral intramedullary (IM) nail procedure: proximal guidewire entry and distal locking.For the validation study, participants performed the above tasks on the simulator. Metrics were collected including time taken, number of X-rays and tool distance travelled and used to assess construct validity. A questionnaire was then completed to assess authenticity and content validity.

SETTING

Simulator development in centre for simulation and engagement science laboratory. Validation study in a teaching hospital environment.

PARTICIPANTS

Orthopedic specialist trainees and consultants.

RESULTS

Surgeon experience (number of IM nails performed/postgraduate year) correlated with significantly improved task performance. More experienced surgeons took less time, used fewer X-rays and had greater economy of movement than less experienced surgeons. Authenticity and content validity were well rated, with criticisms primarily due to hardware limitations.

CONCLUSIONS

To our knowledge this is the first orthopedic simulator to combine immersive VR with haptics and full image intensifier functionality. By combining multiple aspects of surgical practice within a single device, we aimed to improve participant immersion and educational value. Our work so far has focused on technical skills, demonstrating good authenticity, content and construct validity, however our findings show promise in other applications such as nontechnical skill development and assessment.

Accessing 3D Printed Vascular Phantoms for Procedural Simulation

Introduction: 3D printed patient-specific vascular phantoms provide superior anatomical insights for simulating complex endovascular procedures. Currently, lack of exposure to the technology poses a barrier for adoption. We offer an accessible, low-cost guide to producing vascular anatomical models using routine CT angiography, open source software packages and a variety of 3D printing technologies.

Methods: Although applicable to all vascular territories, we illustrate our methodology using Abdominal Aortic Aneurysms (AAAs) due to the strong interest in this area. CT aortograms acquired as part of routine care were converted to representative patient-specific 3D models, and then printed using a variety of 3D printing technologies to assess their material suitability as aortic phantoms. Depending on the technology, phantoms cost $20–$1,000 and were produced in 12–48 h. This technique was used to generate hollow 3D printed thoracoabdominal aortas visible under fluoroscopy.

Results: 3D printed AAA phantoms were a valuable addition to standard CT angiogram reconstructions in the simulation of complex cases, such as short or very angulated necks, or for positioning fenestrations in juxtarenal aneurysms. Hollow flexible models were particularly useful for device selection and in planning of fenestrated EVAR. In addition, these models have demonstrated utility other settings, such as patient education and engagement, and trainee and anatomical education. Further study is required to establish a material with optimal cost, haptic and fluoroscopic fidelity.

Conclusion: We share our experiences and methodology for developing inexpensive 3D printed vascular phantoms which despite material limitations, successfully mimic the procedural challenges encountered during live endovascular surgery. As the technology continues to improve, 3D printed vascular phantoms have the potential to disrupt how endovascular procedures are planned and taught.

Utilization of a three-dimensional printed kidney model for favorable TRIFECTA achievement in early experience of robot-assisted partial nephrectomy

Background

This retrospective study aimed to investigate whether a three-dimensional (3D) model would improve the achievement of TRIFECTA, which was defined as the absence of perioperative complications and positive surgical margins and a warm ischemia time of <25 minutes, during robot-assisted partial nephrectomy (RAPN).

Methods

Prior to RAPN, a 3D-square type kidney model was prepared and used for all RAPN procedures in patients with T1a renal cell carcinoma (RCC) treated at a single center between March 2016 and April 2019. All RAPN procedures were performed by a single surgeon.

Results

The study included 50 patients, of whom 22, 24, and 4 had low-, intermediate-, and high-risk R.E.N.A.L Nephrometry scores, respectively. The TRIFECTA achievement rate was 86.0%, and transfusion or conversion to radical nephrectomy was not required in any of the patients. Only one Clavien-Dindo grade 3 complication was reported—a pseudoaneurysm that required embolism. The TRIFECTA achievement rate was independent of the R.E.N.A.L Nephrometry scores and the surgeon’s experience level (25 cases each of early and advanced experience).

Conclusions

The 3D model contributed to the achievement of TRIFECTA during RAPN performed by a less-experienced surgeon. These findings should be further evaluated in studies involving a larger number of cases and surgeons.

Realization of Open Software Chain for 3D Modeling and Printing of Organs in Simulation Centers: Example of Renal Pelvis Reconstruction

OBJECTIVE

Three-dimensional (3D) printing has many uses in healthcare such as in surgical training. It is becoming an interesting tool finding new pedagogical purposes in medical simulation. In this study, using a process consisting of 3D modeling, a simulator dedicated to pyeloplasty was designed, manufactured, and evaluated by experts.

DESIGN

With the aid of open-source software and computer-aided design software, 3D models of a renal parenchyma, a renal pelvis and a ureter were created. This renal apparatus was processed and crafted with additive manufacturing using soft polymer materials. Polyvinyl alcohol material was used to print the components in order to make them dissectible and to evaluate their use in surgical teaching.

SETTING AND PARTICIPANTS

Seven expert surgeons evaluated the model by performing a pyeloplasty sequence established in a previous work. An evaluation grid with 8 items related to surgical movement was rated on a 5-point Likert scale to assess how similar working with the model was to actual surgery.

RESULTS

Three items were rated with a score greater than or equal to 4 (Needle penetration, Thread-sliding, and Cutting Strength). Suture strength was rated with a score above 3.5 for both renal pelvis and ureter, whereas elasticity was rated below 3. Handling and mobility properties were rated above 3 for the renal pelvis and below 3 for the ureter. The cost of the unit was $0.30 per renal unit. The primary difference identified was a difference in elongation between polyvinyl alcohol material and real biological tissue.

CONCLUSIONS

It is feasible to generate and print a low cost upper urinary tract model from patient data imagery using environmentally friendly products that can be used effectively in surgical training. The simulator has been able to reproduce sensations related to surgical movements for a low cost. Hereafter, research into the pedagogical benefits provided to students, and through them, patients, should be performed. 3D printing models can offer new opportunities for healthcare simulation specific to different surgical fields.

Personalised three-dimensional printed transparent kidney model for robot-assisted partial nephrectomy in patients with complex renal tumours (R.E.N.A.L. nephrometry score ≥7): a prospective case-matched study

OBJECTIVES

To evaluate the effectiveness of a three-dimensional (3D) printed transparent kidney model as a surgical navigator for robot-assisted partial nephrectomy (RPN) in patients with complex renal tumours, defined by a R.E.N.A.L. (Radius, Exophytic/Endophytic, Nearness, Anterior/Posterior, Location) nephrometry score of ≥7.

PATIENTS AND METHODS

A total of 80 patients who underwent RPN were included in the present prospective case-matched study (case group [n = 40, application of 3D-printed transparent kidney model during RPN] vs matching group [n = 40, routine protocol]). The RPNs were performed by a single experienced surgeon. The RPN procedure consisted of six steps: (i) preparation of the renal hilar vessel for clamping, (ii) tumour detection and dissection, (iii) robotic ultrasonography, (iv) tumour resection, (v) calyx repair and haemostasis, and (vi) renorrhaphy. The time for each step, console time, and warm ischaemia time were compared between the two groups as a surrogate marker for surgical effectiveness.

RESULTS

Both groups were well-balanced for all baseline characteristics. The use of the model reduced the console time by ~20% compared to the matched group (64.6 vs 78.5 min, P = 0.001). On multivariate logistic regression analysis, tumour radius (P < 0.001) and application of the model (P = 0.009) were identified as significant predictors of a console time of ≤70 min.

CONCLUSION

We established the usefulness of a personalised 3D-printed transparent kidney model for more effective RPNs. Use of the 3D-printed transparent kidney model reduced the operative time even for complex renal tumours and would be expected to broaden the indications for PN.

Validation of a three-dimensional printed model for training of surgical extraction of supernumerary teeth

INTRODUCTION

This study aimed to validate a three-dimensional (3D) printed model to provide training for supernumerary teeth (SNTs) extraction.

MATERIALS AND METHODS

Each of the 30 participants, grouped as experienced and without experience, conducted two identically simulated surgeries on a 3D-printed replica of human mixed dentition with a SNT. The surgery time, area of bony window and volume of removed material were measured; subsequently, responses to a five-item questionnaire were recorded. The collected data were statistically analysed.

RESULTS

The surgery time was 228.37 ± 141.53 seconds and 125.47 ± 53.03 seconds in the first and second surgery, respectively. The training significantly decreased the surgery time in the participants without experience (P = .000). However, there were no significant differences in the area of window opening (P = .271) and volume of removed material between the two surgeries (P = .075). The participants who perceived educational benefits accounted for more than 60% of the respondents for every question. Participants without experience in SNT extraction showed a tendency to rate a higher score than did those with experience.

CONCLUSIONS

A 3D-printed model for surgical extraction of a SNT can improve surgical skill and, especially, shorten the learning curve in beginners.

[Use of personalized 3D printed kidney models for partial nephrectomy]

Partial nephrectomy is a first-line treatment option for the management of renal tumors. It is a surgical procedure whose complexity and stakes vary according to the specific anatomy of the patient and his tumor. 3D modeling and 3D printing have become a means of representing and thus visualizing the tumor lesion and its anatomical relationships within the organ. This mode of visualization allows the surgeon and his team, but also the patient, to easily realize the tumor complexity, the predictable difficulty of the surgery and therefore the risks of complications. Various publications have reported the benefit to the patient in terms of pre-therapy education. Some have shown a benefit for the operator in terms of surgical planning. Finally, studies on preoperative surgical simulation showed shorter kidney lumpectomy times and less bleeding when surgeons were able to train before the operation on the corresponding 3D printed model. 3D printing therefore represents an innovative tool that would improve patient management prior to partial nephrectomy, through the information it can deliver, but also through surgical simulation.

3D-printed models and virtual reality as new tools for image-guided robot-assisted nephron-sparing surgery: a systematic review of the newest evidences

PURPOSE OF REVIEW

Nowadays, kidney cancer surgery has been focusing on a patient-tailored management, expanding the indication to nephron-sparing surgery (NSS). Starting from computer tomography images, 3D models can be created, allowing a never experienced before understanding of surgical anatomy. Once obtained the models can be printed or virtually visualized with the aid to assist the surgeon in preoperative planning and simulation or intraoperative navigation. The aim of this systematic review is to assess the preoperative and intraoperative impact of 3D printed and virtual imaging for robotic NSS.

RECENT FINDINGS

Ten articles were found to meet the inclusion criteria and reviewed. An 'intermediate' score was assessed to the overall articles' quality. A moderate/high risk of bias was recorded for all the studies.

SUMMARY

3D-printed models were considered to be more useful during both preoperative simulations and patients' counseling. These models guaranteed a better comprehension of anatomical structures and surgical procedure. Costs and quality of the materials available represent the two main limits of this developing technology.Instead, in a virtual reality setting the preoperative planning was enhanced by using 3D virtual models in a mixed reality environment. Intraoperatively, the possibility to overlap the 3D model to real anatomy allowed augmented reality procedures. This technology is still a 'newborn' and is constantly evolving, expanding day by day the range of its potential applications.

Variability in accuracy of prostate cancer segmentation among radiologists, urologists, and scientists

Background

There is increasing research in using segmentation of prostate cancer to create a digital 3D model from magnetic resonance imaging (MRI) scans for purposes of education or surgical planning. However, the variation in segmentation of prostate cancer among users and potential inaccuracy has not been studied.

Methods

Four consultant radiologists, four consultant urologists, four urology trainees, and four nonclinician segmentation scientists were asked to segment a single slice of a lateral T3 prostate tumor on MRI (“Prostate 1”), an anterior zone prostate tumor MRI (“Prostate 2”), and a kidney tumor computed tomography (CT) scan (“Kidney”). Time taken and self‐rated subjective accuracy out of a maximum score of 10 were recorded. Root mean square error, Dice coefficient, Matthews correlation coefficient, Jaccard index, specificity, and sensitivity were calculated using the radiologists as the ground truth.

Results

There was high variance among the radiologists in segmentation of Prostate 1 and 2 tumors with mean Dice coefficients of 0.81 and 0.58, respectively, compared to 0.96 for the kidney tumor. Urologists and urology trainees had similar accuracy, while nonclinicians had the lowest accuracy scores for Prostate 1 and 2 tumors (0.60 and 0.47) but similar for kidney tumor (0.95). Mean sensitivity in Prostate 1 (0.63) and Prostate 2 (0.61) was lower than specificity (0.92 and 0.93) suggesting under‐segmentation of tumors in the non‐radiologist groups. Participants spent less time on the kidney tumor segmentation and self‐rated accuracy was higher than both prostate tumors.

Conclusion

Segmentation of prostate cancers is more difficult than other anatomy such as kidney tumors. Less experienced participants appear to under‐segment models and underestimate the size of prostate tumors. Segmentation of prostate cancer is highly variable even among radiologists, and 3D modeling for clinical use must be performed with caution. Further work to develop a methodology to maximize segmentation accuracy is needed.

Evaluation of Interactive Virtual Reality as a Preoperative Aid in Localizing Renal Tumors

Introduction: A detailed understanding of renal tumor anatomy is required to perform partial nephrectomy. We evaluated the utility of a CT-based interactive virtual reality (iVR) display to assist surgeons' understanding of the precise location of the renal tumor. Methods: CT scans and iVR models of 11 patients with a mean R.E.N.A.L. nephrometry score of 6.9 were evaluated. Seven faculty urologists and six urology residents reviewed CT scans and positioned each tumor onto a digital three-dimensional model of the same kidney, although without the tumor present. A week later, participants repeated the session using both iVR models and CT scans. For both time points, the overlap between the surgeon-inserted tumor and the actual tumor location was calculated. Participants answered a 1 to 10 Likert scale survey to gauge their understanding of renal and tumor anatomy based on CT alone vs CT+iVR. Results: Median tumor overlap for the entire cohort was 28% after CT review and 42% after CT+iVR (p = 0.05); among faculty urologists, for CT+iVR vs CT alone, percentage overlap improved (47% vs 33%, p = 0.033) and the incidence of 0% overlap decreased (19%-4%, p = 0.024), respectively. Among residents, there was no significant difference for either percentage overlap or 0% overlap for CT vs CT+iVR. The percentage overlap for the two tumors with high R.E.N.A.L. nephrometry scores (i.e., 10) increased from 51% to 67% after using CT+iVR (p = 0.039). The combination of CT+iVR was an independent predictor of improved overlap vs CT alone (odds ratio 2.22, 95% confidence interval 1.04-4.78, p = 0.039). Faculty surgeons' survey responses showed an improved understanding of the tumor location and shape with the addition of iVR (p < 0.05). Conclusions: The addition of patient-specific iVR models to standard CT imaging improved the ability of faculty urologists to accurately configure the location of a renal tumor, and improved their understanding of tumor anatomy.

Three-dimensional printing versus conventional machining in the creation of a meatal urethral dilator: development and mechanical testing

Background

Three-dimensional (3D) printing is a promising technology, but the limitations are often poorly understood. We compare different 3D printing methods with conventional machining techniques in manufacturing meatal urethral dilators which were recently removed from the Australian market.

Methods

A prototype dilator was 3D printed vertically orientated on a low-cost fused deposition modelling (FDM) 3D printer in polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS). It was also 3D printed horizontally orientated in ABS on a high-end FDM 3D printer with soluble support material, as well as on an SLS 3D printer in medical nylon. The dilator was also machined in stainless steel using a lathe. All dilators were tested mechanically in a custom rig by hanging calibrated weights from the handle until the dilator snapped.

Results

The horizontally printed ABS dilator experienced failure at a greater load than the vertically printed PLA and ABS dilators, respectively (503 g vs 283 g vs 163 g, p < 0.001). The SLS nylon dilator and machined steel dilator did not fail. The steel dilator is the most expensive with a quantity of five at 98 USD each, but this decreases to 30 USD each for a quantity of 1000. In contrast, the cost for the SLS dilator is 33 USD each for five and 27 USD each for 1000.

Conclusions

Low-cost FDM 3D printing is not a replacement for conventional manufacturing. 3D printing is best used for patient-specific parts, prototyping or manufacturing complex parts that have additional functionality that cannot otherwise be achieved.

Innovation in Urology: Three Dimensional Printing and Its Clinical Application

Three-dimensional (3D) printing allows rapid prototyping of novel equipment as well as the translation of medical imaging into tangible replicas of patient-specific anatomy. The technology has emerged as a versatile medium for innovation in medicine but with ever-expanding potential uses, does 3D printing represent a valuable adjunct to urological practice? We present a concise systematic review of articles on 3D printing within urology, outlining proposed benefits and the limitations in evidence supporting its utility. We review publications prior to December 2019 using guidelines outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. Of 117 identified articles, 67 are included highlighting key areas of research as the use of patient-specific models for patient education, surgical planning, and surgical training. Further novel applications included printed surgical tools, patient-specific surgical guides, and bioprinting of graft tissues. We conclude to justify its adoption within standard practice, further research is required demonstrating that use of 3D printing can produce; direct and measurable improvements in patient experience, consistent evidence of superior surgical outcomes or simulation which surpasses existing means' both in fidelity and enhancement of surgical skills. Although exploration of 3D printing's urological applications remains nascent, the seemingly limitless scope for innovation and collaborative design afforded by the technology presents undeniable value as a resource and assures a place at the forefront of future advances.

Robotic dismembered pyeloplasty surgical simulation using a 3D-printed silicone-based model: development, face validation and crowdsourced learning outcomes assessment

Ureteropelvic junction obstruction (UPJO) is an uncommonly encountered pathology, posing a challenge for resident training. We describe the development and face validation of a robotic pyeloplasty simulation using a 3D-printed silicone-based model of UPJO for surgical training, in combination with crowdsourced scoring to objectively assess performance and learning outcomes. The organs were created using 3D modeling software and printed using a silicone-based material by Lazarus 3D, LLC. They were secured in a laparoscopic box trainer and the robotic system was docked. Eight residents and three faculty each performed two robotic-assisted right dismembered pyeloplasties on separate occaisions. Face validity was evaluated on a 5-point Likert scale. Crowd-Sourced Assessment of Technical Skills (C-SATS Inc.) scored surgical performance using the Global Evaluative Assessment of Robotic Skills (GEARS) criteria, based on video review of each simulation. All participants completed the simulation twice with fully patent anastomoses. Average time to complete the first and second trials was 44.4 min and 43.2 min, respectively. The average GEARS score was 17.1 and 17.6 for the first and second trials respectively. Participants improved on average in all 5 GEARS categories, with significant improvement in depth perception (p = 0.006). The model received mean scores (out of 5) of 4.36 for aesthetics, 4.18 for overall feel, 3.55 for realism, 4.72 for usability, and 4.72 for suturability. Residents had a significant increase in confidence between initial and final surveys on a 5-point Likert Scale: 1.63 vs. 2.38 (p = 0.03). Using 3D-printed silicone-based models, participants completed robotic-assisted dismembered pyeloplasties for training and skill acquisition. We demonstrated face validity of the simulation, which was also found to improve participant speed and significantly improve resident confidence. Crowdsourced assessment demonstrated significant improvement in depth perception.

Role of 3D printing in surgical education for robotic urology procedures

During the past 5 years, the body of literature surrounding the utilization of three-dimensional (3D) printing in the field of urology has grown exponentially. Incentivized by work hour restrictions, patient safety initiatives, and inspired by technical advances in biomaterials and rapid printing strategies, this emerging, and fascinating area of research has begun to make headway into clinical practice. However, concerns about cost, limited understanding of the technical processes involved, and lack of its potential uses remain barriers to its widespread adoption. We examined existing published literature on how 3D printing technologies have been utilized in the field of Urology to enhance pre-operative planning, revitalize surgical training, and modernize patient education, with particular focus on, robotic surgery. To date, 3D-printed models have been used and studied most commonly in the preoperative planning for nephron-sparing surgeries during the treatment of renal masses, where the challenges of complex renal anatomy and benefits of reducing renal ischemic injury create the most intuitive value. Prostate models are the second most common, particularly in the planning of nerve-sparing procedures. Early studies have demonstrated sufficient realism and educational effectiveness. Subsequent studies demonstrated improved surgeon confidence, operative performance, and optimized patient outcomes including high levels of patient satisfaction. Realistic, accurate, and reasonably priced models can currently be generated within hours using standard desktop 3D printers. While primarily utilized as anatomic replicas of diseased organs that restore a sense of haptic feedback lost in robotic procedures, innovations in polymers, improvements in 3D printer host and modeling software, and upgrades in printer hardware allow this technology to serve as a comprehensive, interactive, simulation platform that can be a critical surgical decision making as well as an effective teaching tool. As Urologists continue to rapidly diversify and iterate upon this adaptive modality, the benefits in patient outcomes will likely outpace the diminishing drawbacks, and we may well see the next revolution in surgical education, robotic techniques, and personalized medicine concurrently.

Current applications of three-dimensional printing in urology

Three-dimensional (3D) printing or additive manufacturing is a new technology that has seen rapid development in recent years with decreasing costs. 3D printing allows the creation of customised, finely detailed constructs. Technological improvements, increased printer availability, decreasing costs, improved cell culture techniques, and biomaterials have enabled complex, novel and individualised medical treatments to be developed. Although the long-term goal of printing biocompatible organs has not yet been achieved, major advances have been made utilising 3D printing in biomedical engineering. In this literature review, we discuss the role of 3D printing in relation to urological surgery. We highlight the common printing methods employed and show examples of clinical urological uses. Currently, 3D printing can be used in urology for education of trainees and patients, surgical planning, creation of urological equipment, and bioprinting. In this review, we summarise the current applications of 3D-printing technology in these areas of urology.

Mechanical and functional validation of a perfused, robot-assisted partial nephrectomy simulation platform using a combination of 3D printing and hydrogel casting

INTRODUCTION AND OBJECTIVES

There is a scarcity of high-fidelity, life-like, standardized and anatomically correct polymer-based kidney models for robot-assisted partial nephrectomy (RAPN) simulation training. The purpose of this technical report is to present mechanical and functional testing data as evidence for utilizing a perfused hydrogel kidney model created utilizing 3D printed injection casts for RAPN simulation and training.

METHODS

Anatomically correct, tumor-laden kidney models were created from 3D-printed casts designed from a patient's CT scan and injected with poly-vinyl alcohol (PVA). A variety of testing methods quantified Young's modulus in addition to comparing the functional effects of bleeding and suturing among fresh porcine kidneys and various formulations of PVA kidneys.

RESULTS

7% PVA at three freeze-thaw cycles (7%-3FT) was found to be the formula that best replicates the mechanical properties of fresh porcine kidney tissue, where mean(± SD) values of Young's modulus of porcine tissue vs 7%-3FT samples were calculated to be 85.97(± 35) kPa vs 80.97(± 9.05) kPa, 15.7(± 1.6) kPa vs 74.56(± 10) kPa and 87.46(± 2.97) kPa vs 83.4(± 0.7) kPa for unconfined compression, indentation and elastography testing, respectively. No significant difference was seen in mean suture tension during renorrhaphy necessary to achieve observable hemostasis and capsular violation during a simulated perfusion at 120 mmHg.

CONCLUSIONS

This is the first study to utilize extensive material testing analyses to determine the mechanical and functional properties of a perfused, inanimate simulation platform for RAPN, fabricated using a combination of image segmentation, 3D printing and PVA casting.

3D printing technology and its role in urological training

PURPOSE

Surgical simulation and 3D printing have both been gaining traction exclusively over the past decade, and now have started to appear simultaneously in current research. The opinion that surgical simulation should be part of surgery curricula is becoming ever more apparent. In this review, we highlight and briefly examine the 3D printing workflow, and each facet of the current body of literature using this technology in the augmentation of surgical training, in addition to the challenges currently faced.

METHODS

A broad literature search was conducted pertaining to the utilisation of 3D printing in urology, aiming to sample the majority of use-cases of this fairly novel technology. The 3D printing workflow, current use-cases of 3D printing as applied to urological training, and challenges faced have been described.

RESULTS

A respectable number of surgical use-cases utilising 3D printing technology in their development were identified, including but not limited to percutaneous nephrolithotomy, partial nephrectomy, renal transplantation, laparoscopic pyeloplasty, prostate brachytherapy, transurethral resection of bladder tumours, urethrovesical anastomosis simulation devices, in addition to laparoscopic trainers and robotic surgery phantoms.

CONCLUSION

Over the last decade, urology has taken this cutting-edge technology in its stride; flaunting its efficacy in the augmentation of a number of procedural training applications. The number of use cases for this technology is only expected to rise as its virtues are demonstrated, the ease of use and availability of 3D printing units advances, and costs abated.

From digital world to real life: a robotic approach to the esophagogastric junction with a 3D printed model

BACKGROUND

Three-dimensional (3D) printing may represent a useful tool to provide, in surgery, a good representation of surgical scenario before surgery, particularly in complex cases. Recently, such a technology has been utilized to plan operative interventions in spinal, neuronal, and cardiac surgeries, but few data are available in the literature about their role in the upper gastrointestinal surgery. The feasibility of this technology has been described in a single case of gastroesophageal reflux disease with complex anatomy due to a markedly tortuous descending aorta.

METHODS

A 65-year-old Caucasian woman was referred to our Department complaining heartburn and pyrosis. A chest computed tomography evidenced a tortuous thoracic aorta and consequent compression of the esophagus between the vessel and left atrium. A "dysphagia aortica" has been diagnosed. Thus, surgical treatment of anti-reflux surgery with separation of the distal esophagus from the aorta was planned. To define the strict relationship between the esophagus and the mediastinal organs, a life-size 3D printed model of the esophagus including the proximal stomach, the thoracic aorta and diaphragmatic crus, based on the patient's CT scan, was manufactured.

RESULTS

The robotic procedure was performed with the da Vinci Surgical System and lasted 175 min. The surgeons had navigational guidance during the procedure since they could consult the 3D electronically superimposed processed images, in a "picture-in-picture" mode, over the surgical field displayed on the monitor as well as on the robotic headset. There was no injury to the surrounding organs and, most importantly, the patient had an uncomplicated postoperative course.

CONCLUSIONS

The present clinical report highlights the feasibility, utility and clinical effects of 3D printing technology for preoperative planning and intraoperative guidance in surgery, including the esophagogastric field. However, the lack of published data requires more evidence to assess the effectiveness and safety of this novel surgical-applied printing technology.

An overview on 3D printing for abdominal surgery

BACKGROUND

Three-dimensional (3D) printing is a disruptive technology that is quickly spreading to many fields, including healthcare. In this context, it allows the creation of graspable, patient-specific, anatomical models generated from medical images. The ability to hold and show a physical object speeds up and facilitates the understanding of anatomical details, eases patient counseling and contributes to the education and training of students and residents. Several medical specialties are currently exploring the potential of this technology, including general surgery.

METHODS

In this review, we provide an overview on the available 3D printing technologies, together with a systematic analysis of the medical literature dedicated to its application for abdominal surgery. Our experience with the first clinical laboratory for 3D printing in Italy is also reported.

RESULTS

There was a tenfold increase in the number of publications per year over the last decade. About 70% of these papers focused on kidney and liver models, produced primarily for pre-interventional planning, as well as for educational and training purposes. The most used printing technologies are material jetting and material extrusion. Seventy-three percent of publications reported on fewer than ten clinical cases.

CONCLUSION

The increasing application of 3D printing in abdominal surgery reflects the dawn of a new technology, although it is still in its infancy. The potential benefit of this technology is clear, however, and it may soon lead to the development of new hospital facilities to improve surgical training, research, and patient care.

Three-dimensional printing for laparoscopic partial nephrectomy in patients with renal tumors

Objectives

To explore the efficacy of three-dimensional printing physical model-assisted laparoscopic partial nephrectomy (3D-LPN) in patients with renal tumors.

Methods

We retrospectively assessed all patients who underwent LPN with or without 3D-printed physical model assistance from January 2016 to February 2018 at our institution. The demographic characteristics, operative findings, and clinical outcomes from the procedure were collected and analyzed.

Results

Sixty-nine patients underwent 3D-LPN and 58 underwent traditional LPN. The groups showed no differences in demographics, RENAL score, surgical approach, operative time, estimated intra-/postoperative blood loss, increased creatinine level, or complications. In the 3D-LPN group, warm ischemia time was shorter, whereas surgery waiting time was longer, compared with those parameters in the LPN group. Subgroup analysis indicated that for patients with RENAL score ≥8, the 3D-LPN group had significantly shorter warm ischemic time and less intraoperative blood loss than the traditional LPN group. Intra- and postoperative hospital complication rates were similar for 3D-LPN and traditional LPN groups (8.7% vs. 13.7%).

Conclusions

3D printing provides an additional tool to assist with LPN. Use of a 3D model can assist in planning and performance of LPN in patients with RENAL score ≥8.

A Systematic Review of the Clinical Value and Applications of Three-Dimensional Printing in Renal Surgery

The purpose of this systematic review is to collate and analyse the current literature which examines clinical applications of 3D printing for renal disease, alongside cost and time duration factors associated with the printing process. A comprehensive search of the literature was performed across five different databases to identify studies that qualitatively and quantitatively assessed the value of 3D-printed kidney models for renal disease. Twenty-seven studies met the selection criteria for inclusion in the review. Twenty-five were original studies, and two were case reports. Of the 22 studies reporting a qualitative evaluation, the analysis of findings demonstrated the value of the 3D-printed models in areas of clinician and patient education, and pre-surgical simulation for complex cases of renal disease. Of five studies performing a quantitative analysis, the analysis of results displayed a high level of spatial and anatomical accuracy amongst models, with benefits including reducing estimated blood loss and risk of intra-operative complications. Fourteen studies evaluated manufacturing costs and time duration, with costs ranging from USD 1 to 1000 per model, and time duration ranging from 15 min to 9 days. This review shows that the use of customised 3D-printed models is valuable in the education of junior surgeons as well as the enhancement of operative skills for senior surgeons due to a superior visualisation of anatomical networks and pathologic morphology compared to volumetric imaging alone. Furthermore, 3D-printed kidney models may facilitate interdisciplinary communication and decision-making regarding the management of patients undergoing operative treatment for renal disease. It cannot be suggested that a more expensive material constitutes a higher level of user-satisfaction and model accuracy. However, higher costs in the manufacturing of the 3D-printed models reported, on average, a slightly shorter time duration for the 3D-printing process and total manufacturing time.