External Validation of the "Tor Vergata" 3D Printed Models of the Upper Urinary Tract and Stones for High-Fidelity Simulation of Retrograde Intrarenal Surgery.

Introduction: Novel training modalities are being investigated to overcome the challenges associated with learning retrograde intrarenal surgery (RIRS). Consequently, a series of 3D printed models of the upper urinary tract and stones designed for ex vivo surgical simulation was introduced in 2021. This study aims to provide external validation of the training model and assess its role in the development of surgical skills. Materials and Methods: A mixed cohort of 20 urologists at different levels of expertise participated in a whole-day live simulation event to examine the model and perform a timed simulation of intrarenal navigation, stone relocation, and laser fragmentation. Operative times were recorded and two independent expert endourologists scored the simulations according to a modified "Objective Structured Assessment of Technical Skills" (OSATS) scale. Five novice urologists from the cohort performed three further simulations in a subsequent event to assess improvement in surgical skills. Results: Face validity was demonstrated with a median score of ≥4/5 in each of the 11 items investigated. Content validity was also effectively reached, with 100% positive impressions with regard to the usefulness for the acquisition of surgical skills. Significant differences were observed among operative times stratified per surgeon experience (all p < 0.0050), thus providing construct validity. Median total OSATS score for novices was 14 (range 8, 25) and was found to be significantly different from expected expert performance (p = 0.0010). Repeated simulations by novices led to a progressive reduction of operative times (p = 0.0313) and increase in median total OSATS (p = 0.0625). Conclusion: The 3D printed models of upper urinary tract and synthetic training stones for the high-fidelity simulation of each phase of RIRS were validated by this study. The results encourage the usage of the models in simulation courses and the evaluation of their potential role in standardized training curricula.

Introducing 3D printed models of the upper urinary tract for high-fidelity simulation of retrograde intrarenal surgery.

PURPOSE: Training in retrograde intrarenal surgery for the treatment of renal stone disease is a challenging task due to the unique complexity of the procedure. This study introduces a series of 3D printed models of upper urinary tract and stones designed to improve the training process. METHODS: Six different models of upper urinary tract were algorithmically isolated, digitally optimized and 3D printed from real-life cases. Soft and hard stones in different sizes were produced from 3D printed moulds. The models were fitted onto a commercially available part-task trainer and tested for retrograde intrarenal surgery. RESULTS: Each step of the procedure was simulated with extraordinary resemblance to real-life cases. The unique anatomical intricacy of each model and type of stones allowed us to reproduce surgeries of increasing difficulty. As the case-load required to achieve proficiency in retrograde intrarenal surgery is high, benchtop simulation could be integrated in training programs to reach good outcomes and low complication rates faster. Our models match incredible anatomical resemblance with low production cost and high reusability. Validation studies and objective skills assessment during simulations would allow comparison with other available benchtop trainers and the design of stepwise training programs. CONCLUSIONS: 3D printing is gaining a significant importance in surgical training. Our 3D printed models of the upper urinary tract might represent a risk-free training option to hasten the achievement of proficiency in endourology.

3D mixed reality holograms for preoperative surgical planning of nephron-sparing surgery: evaluation of surgeons' perception.

BACKGROUND: 3D reconstructions are gaining a wide diffusion in nephron-sparing surgery (NSS) planning. They have usually been studied on common 2D flat supports, with limitations regarding real depth comprehension and interaction. Nowadays, it is possible to visualize kidney 3D reconstructions as holograms in a "mixed reality" (MR) setting. The aim of this study was to test the face and content validity of this technology, and to assess the role of 3D holograms in aiding preoperative planning for highly complex renal tumors amenable by NSS. METHODS: We evaluated surgeons' perception of mixed reality for partial nephrectomy during a urological international meeting organized at our Institution in January 2019. Thanks to the images of preoperative CT, hyper-accuracy 3D (HA3DTM) reconstructions were performed. Then, a virtual environment was created, and it interacted with the models in mixed reality setting by using HoloLens. We submitted to all the attendees a questionnaire, expressed by the Likert scale (1-10), about their opinion over the use and application of the MR. Moreover, the attendees had the chance to perform a first-hand MR experience; then, they were asked to choose their clamping and resection approach. RESULTS: Overall 172 questionnaires were collected. The scores obtained regarding both surgical planning (scored 8/10) and anatomical accuracy (9/10) were very positive. High satisfaction toward the potential role of this technology in surgical planning and understanding of surgical complexity (both scored 9/10) were expressed. After a first-hand experience with HoloLens and MR, 64.4% and 44.4% of the surgeons changed their clamping and resection approach, respectively - compared to CT image visualization only - choosing a more selective one. CONCLUSIONS: Our study suggests that surgeons perceive holograms and MR as a useful and interesting tool for the preoperative setting before partial nephrectomy, in the direction of an ever more precise surgery.

Three-dimensional Elastic Augmented-reality Robot-assisted Radical Prostatectomy Using Hyperaccuracy Three-dimensional Reconstruction Technology: A Step Further in the Identification of Capsular Involvement.

BACKGROUND: In prostate cancer (PCa) surgical procedures, in order to maximize potency recovery, a nerve-sparing (NS) procedure is preferred. However, cancer abutting or focally extending beyond the prostate capsule increases the risk of a positive surgical margin. OBJECTIVE: To evaluate the accuracy of our new three-dimensional (3D) elastic augmented-reality (AR) system in identifying capsular involvement (CI) location of PCa during the NS phase of robot-assisted radical prostatectomy (RARP). Secondarily, the accuracy of this technology was compared with two-dimensional (2D)-based cognitive procedures. DESIGN, SETTING, AND PARTICIPANTS: A prospective study, enrolling 40 patients with PCa undergoing RARP at our center, from May to October 2018. SURGICAL PROCEDURE: Patients underwent 3D AR RARP or, in case of unavailability of this technology, 2D cognitive RARP. In all patients, total anatomical reconstruction was used. MEASUREMENTS: Clinical data were collected. In order to compare the two groups, nonparametric Mann-Whitney and chi-square tests were performed. A metallic clip was placed at the level of suspicious CI on the basis of images given by the 3D AR or magnetic resonance imaging (MRI) report. The pathological analysis evaluated the presence of tumor at the level of the clip. RESULTS AND LIMITATIONS: Twenty patients were enrolled in each group. Focusing on the 3D AR group at macroscopic evaluation, the metallic clip was placed at the tumor and capsular bulging in all cases. At microscopic assessment, cancer presence was confirmed in the suspicious area in 95.4% of the cases. Moreover, CI was correctly identified in 100.0% of the cases, thanks to the 3D image overlap. These results were compared with the 2D MRI cognitive group, showing, at microscopic analysis, statistically significant superiority of the 3D AR group in CI detection during the NS phase (100% vs 47.0%; p<0.05). The main limitation of this technique is that the segmentation and overlapping of the images are performed manually. CONCLUSIONS: Our findings suggest that, with the introduction of the elastic 3D virtual models, prostate deformation is correctly simulated during surgery and lesion location is correctly identified, even in dynamic reality with a subsequent potential reduction of positive surgical margin rate and, in the meantime, maximization of functional outcomes. PATIENT SUMMARY: On the basis of our findings, the three-dimensional elastic augmented-reality technology seems to help the surgeon in lesion location identification even in a dynamic phase of the intervention, optimizing the oncological outcomes.