Endourological Training Using 3D-Printed Bladder Phantoms: Development and Prospective Evaluation

Background: To create and evaluate a realistic, anatomically accurate, and user-friendly bladder phantom for reproducible endourological training purposes and endoscope mastery. Materials and Methods: The anatomy of full bladders was mapped from human computed tomography datasets. After a 3D model development process, content evidence and response process evidence (RPE) of the phantom were evaluated using the system usability scale (SUS), 5-point Likert scale questionnaires, and task execution of experienced urologists (U) and endoscopy-naive medical students (MS) in two training sessions (first vs second). Required validation cohort sizes (1:10) of the evaluating urologists (n = 12) and students (n = 115) were precalculated. Time measurements were recorded. Students were additionally evaluated by a validated global psychomotor assessment score (GPSS). Group comparisons were calculated by the Mann-Whitney U test. All tests were two sided with p < 0.05 considered statistically significant. Results: Content evidence was assessed by urologists with an "excellent" SUS score of 89.4 +/- 5.9 and an average "agreement" of >= 4 pts in the Likert scale questionnaires. RPE was assessed by intra- and intergroup time comparison for the execution of endoscopic tasks (cystoscopy [CY], guidewire insertion, and tumor biopsy). For CY, U: first 17.6 +/- 4.4 seconds vs second 12.4 +/- 2.0 seconds, p = 0.002; MS: first 56.6 +/- 28.2 seconds vs second 28.6 +/- 14.7 seconds, p < 0.001; U vs MS: first U 17.6 +/- 4.4 seconds vs first MS 56.6 +/- 28.2 seconds, p < 0.001, second U 12.4 +/- 2.0 seconds vs second MS 28.6 +/- 14.7 seconds, p < 0.001. Significant time differences were documented for all tasks and sessions (p < 0.001). Additionally, significant GPSS differences were recorded between the sessions (GPSS: first 20.4 +/- 5.1 pts vs second 24.7 +/- 4.0 pts, p < 0.001). Conclusions: Our low-fidelity 3D-printed bladder, called BladCap, is an easy-to-assemble, inexpensive, and robust phantom. We present data, which establish construct validity to support use as a clinical training device.