Stone Clearance by Computed Tomography after Percutaneous Nephrolithotomy: A Descriptive Cross-sectional Study

Abstract

Introduction: Percutaneous nephrolithotomy has the highest stone free rate among other procedures with relatively higher complication rate. Post-operative imaging after stone surgeries has not been uniform. This study was done to study about the stone clearance by computed tomography after percutaneous nephrolithotomy.

Methods: The descriptive cross-sectional study was conducted in the Department of Urology, Bir Hospital for six months duration. The patients undergoing percutaneous nephrolithotomy and those with intra-operative fluoroscopic clearance were evaluated with a low dose computed tomography after 48 hours to assess residual fragments its size and location. Patient’s demographics, stone characteristics and complications were compared between the stone free and with residual stone patients.

Results: Out of 72 percutaneous nephrolithotomy performed, 40 patients were included in the study. Low dose computed tomography kidney, ureter and bladder after 48 hours of surgery detected residual fragments in 11 (27.5%) patients. The RFs size of <4mm were found in 7 (63.63%) of cases whereas RFs of >4mm were found in 4 (36.36%). The stone size was 352.47 ± 97.47 mm2 and 254.79 ± 172.68mm2 in group with residual fragments and stone free group respectively.

Conclusions: Low dose computed tomography kidney, ureter and bladder done for assessment of stone clearance after 48 hours of percutaneous nephrolithomy detected residual in around one fourth of patients, however majority of them had residual fragments <4mm. Intra-operative fluoroscopic clearance may over estimate stone clearance after percutaneous nephrolithomy as about one third of patients still may have residual fragments of >4mm size.