Effects of Three-dimensional Measurement of the Urinary Stone Size on the Surgical Outcomes of Retrograde Intrarenal Stone Surgery

Abstract

Objective: This study aimed to investigate peri-/postoperative effects of three-dimensional measurement of stone size in patients who underwent retrograde intrarenal surgery, where preoperative stone size calculations determine the operation decisions and prognosis. Another aim is to determine a limit value in cm(3) for retrograde intrarenal surgery and to predict stone-free status based on this limit value. Materials and Methods: Data of 184 patients were retrospectively analysed. Patients were divided into two groups according to whether the stone-free status was achieved. Postoperative stone-free status and related effective parameters were analysed statistically. Results: No significant difference was found between age, gender, Hounsfield unit, length of hospital stay, secondary retrograde intrarenal surgery, renal unit abnormality, stone side, stone opacity, presence of additional ureteral stone, hydronephrosis and preoperative Double-J stent placement with stone-free rate. Subsequent interventions for residual stones, number of stones, stone sizes in cm(2) and cm(3) and operation time were determined as parameters that significantly affected the stone-free rate. As a result of the receiver operating characteristic analysis, the threshold stone size was 1.54 cm(3). Conclusion: More accurate indications can be determined by calculating the volume of the stone. Retrograde intrarenal surgery success decreases in stones >1.54 cm(3) by volume calculation. A different method such as percutaneous nephrolithotomy should be considered with higher preference for stones above this value.