Impact of stone volume on treatment outcomes of percutaneous nephrolithotripsy.

ABSTRACT

PURPOSE: We aimed to evaluate the impact of stone volume on the surgical outcomes of patients who underwent percutaneous nephrolithotripsy, which is the preferred treatment for renal and upper ureteral stones. MATERIALS AND METHODS: This retrospective study included 37 patients who underwent percutaneous lithotripsy between 2013 and 2019. Preoperative and postoperative stone volumes were quantified using computed tomography scan data. RESULTS: The mean preoperative and postoperative stone volumes were 10.7 cm3 (1.1-50.2 cm3 ) and 2.1 cm3 (0-18.2 cm3 ), respectively. The correlation coefficient between the stone volume and maximum stone length was 0.62 (P < .01). A residual stone volume of >5 mm was observed in 17 cases (45.9%). Thirteen cases underwent secondary treatment (35.1%) who had a preoperative stone volume of >15 cm3 or a postoperative stone volume of <2 cm3 . The areas under the curve for the stone volume for treatment success and the requirement for secondary treatment were 0.701 and 0.739, respectively, and were higher than those of stone length (0.638 and 0.558) and shape (0.644 and 0.641). CONCLUSIONS: Measurement of stone volume using three-dimensional imaging is simple and greatly impacted the course of stone treatment. Information on stone volume may predict an increased likelihood of secondary treatment in patients with a preoperative stone volume of >15 cm3 .