Development of an Improved Cadaveric Training Model for Endoscopic Combined Intrarenal Surgery Using Fresh‐Frozen Cadavers

ABSTRACT Objectives Endoscopic combined intrarenal surgery (ECIRS) is technically demanding and has a prolonged learning curve. Reports describing ECIRS training using fresh‐frozen cadavers are limited, partly because intrarenal and pyelovenous backflow may prevent adequate hydronephrosis. This study aimed to establish an optimized ECIRS training model using fresh‐frozen cadavers. Methods ECIRS cadaver surgical training (ECIRS‐CST) was conducted between April 2021 and October 2022 and evaluated across two periods. In the first period, standard ECIRS‐CST was performed. In the second period, laparoscopic nephrectomy training with renal vein clipping was performed before ECIRS‐CST to suppress pyelovenous backflow. Achievement of each ECIRS step and overall procedural completion were recorded. Participants assessed procedural realism and educational value using a custom‐designed 5‐point Likert‐scale questionnaire. Results Nine sessions were conducted in the first period and four in the second. During the first period, ultrasound‐guided nephrostomy puncture frequently failed because adequate hydronephrosis could not be established, and only three sessions progressed through all ECIRS steps. In the second period, renal vein clipping enabled more consistent hydronephrosis, resulting in successful nephrostomy puncture and completion of all steps in three of four sessions. Questionnaire responses indicated that tactile feedback during puncture, ultrasonographic visualization, and endoscopic findings were comparable to those in live patients. Many participants reported difficulty in achieving sufficient hydronephrosis during the first period. Conclusions Fresh‐frozen cadavers provide a realistic environment for ECIRS training; however, pyelovenous backflow limits the creation of adequate hydronephrosis. Renal vein clipping effectively addresses this limitation and provides a more reliable training model for procedural training.