Which is More Accurate? Urologist or STONE Nomogram: An Original Study

Background: Comparing and determining the accuracy of -urolo gists and STONE nomogram prediction about the Percutaneous Nephrolithotomy (PCNL) outcomes in urolithiasis patients. Methods: This retrospective cohort study was performed on 70 patients who underwent PCNL in Firoozgar Hospital (Tehran, Iran) from March 2019 to April 2020. Two expert urologists, who were not informed about the actual result of the procedure and did not have access to the post-operative data, were asked to predict the success rate of PCNL based on pre-operative imaging. The remaining stone size of less than 4 mm was considered as stone-free in PCNL. On the other hand, the STONE nomogram calculated the stone-free rate, and if the predicted success rate was over 60%, PCNL was considered successful based on the STONE nomogram. Results: The accuracy of the urologist’s prediction was 76.42%. The STONE nomogram correctly predicted the PCNL result in 59 cases (84.28%). There was a significant correlation between the actual success rate of the PCNL and the nomogram’s prediction (p-value= 1.013×10-5). There was no significant difference between the surgeons and the nomogram’s prediction (p-value=0.336). The number of stones did not significantly affect the correct prediction of surgical results (p-value<0.05). Upper calyx stones caused a significant difference between correct prediction of surgical results by surgeons and nomograms (p-value<0.05). Conclusion: No significant difference was found between surgeons’ prediction and STONE nomogram, but only in patients with kidney stones in the upper calyx; the nomogram’s prediction accuracy was higher.