Value of Intraoperative Ultrasound in Decreasing Incidence of Residual Radiolucent Stones Post- Percutaneous Nephrolithotomy

Abstract

Background: Percutaneous nephrolithotomy (PCNL) is the gold standard treatment for large renal calculi. The primary goal of treatment is absolute clearance of stone. The incidence of residual stones after PCNL ranges from 10% to 60% and may be higher in radiolucent stones. Aim of work:Our objective was to assess the effectiveness of using ultrasound during PCNL in patients with radiolucent stones in reducing the incidence of residual fragments postoperatively. Patients and Methods:This was a single-center prospective study over a 6 year period. We identified 86 patients undergoing PCNL with radiolucent stones. Ultrasound was used in conjunction with traditional fluoroscopy to identify residual fragments. Each patient had a first-day postoperative computed tomography to assess for residual fragments. The sensitivity of ultrasound with fluoroscopy was compared to clinically or radiologically [CT] detected residual fragments.Results: Our overall stone clearance rate was 82.6% [as evidenced by postoperative CT]. The sensitivity of intraoperative ultrasound, when compared to postoperative CT, was 95.8%, specificity 40.0%, the positive predictive value 88.3%, and negative predictive value 66.7% Conclusions: The use of intraoperative ultrasound during PCNL for radiolucent stones may help in the reduction of postoperative imaging. However, future studies are recommended.