Intraoperative Assessment of Stone Free Status for Percutaneous Nephrolithotomy Surgery: Surgeon’s Eye

Abstract

Objective: In patients who underwent percutaneous nephrolithotomy(PNL),it was aimed to determine the accuracy of the surgeon's intraoperative stone-free status(SFS) prediction,the factors affecting it,the predictors that caused the wrong estimation, and finally to evaluate the reliability of the "surgeon's eye".
 
 Material and Methods: The data of 1025 patients who underwent PNL and met the inclusion criteria were evaluated retrospectively.Since the basis of our study was based on the evaluation of the surgeon's stone-free prediction,patients identified as "absence of residual stone fragment(RF)" by the surgeon were grouped and compared with postoperative computed tomography imaging according to the presence of RF.
 
 Results: Sensitivity, specificity, positive predictive value and negative predictive value were calculated as 67.87%, 96.23%, 91.67% and 83.04%, respectively.In our study, it was found that the "surgeon's eye" predicted SFS incorrectly at a rate of 16.9%.There was no statistically significant correlation between gender,stone side,stone density and hemoglobin decrease between the two groups.Stone size,operation time,fluoroscopy time,location of the stone,number of stones in the calyces and GUY's stone score(GSS) were statistically significantly associated with "surgeon's eye".As a result of multivariate logistic regression analysis of the parameters that were found to have a statistically significant relationship with the surgeon's eye,stone size,the number of stones in the calyces and GSS were significant predictors.
 
 Conclusion: The most important predictors of "surgeon's eye" in PNL were stone size,number of stones in the calyces and GSS. These predictors can be used as an effective criterion in the use of methods to reduce radiation exposure in postoperative imaging of patients who are predicted to be stone-free.