Objective <p>Fluoroscopic access techniques may not reliably differentiate between papillary and non-papillary renal access during percutaneous nephrolithotomy (PNL), potentially leading to misinterpretations that could increase complication risks. This pilot study aimed to evaluate whether a novel radiopaque 3D-printed collecting system model could be used to investigate the feasibility of identifying non-papillary accesses using different biplanar fluoroscopic techniques in the supine PNL setting.</p> Materials and methods <p>This experimental study was conducted in February 2023 using a 3D-printed Dentagum resin model of the renal collecting system fixed in a supine position. Five intentionally non-papillary accesses (two lower calyces, three middle calyces) that appeared papillary at a 0° fluoroscopic angle were created. Four biplanar fluoroscopic access techniques (0–30° cephalad, 0–30° caudal, 0–20° lateral, and 0–90°) were then employed to detect whether these accesses could be identified as non-papillary.</p> Results <p>Among the five non-papillary accesses, 0–30° cephalad detected one (20%), 0–30° caudal detected two (40%), and 0–90° detected two (40%), while 0–20° lateral detected none. Both non-papillary accesses in the lower calyx were correctly identified using 0–90°, with one additionally detected by 0–30° cephalad and the other by 0–30° caudal. Of the three non-papillary middle calyx accesses, only one was detected (via 0–30° caudal), whereas the other two were missed by all tested angles. Additional angles (e.g., 60° lateral–30° cephalad) further increased non-papillary detection rates.</p> Conclusions <p>This pilot study demonstrates that non-papillary accesses may appear papillary under standard biplanar fluoroscopic techniques, suggesting a risk of misinterpretation and underscoring the potential benefit of incorporating additional imaging angles to improve detection accuracy.</p>