MP30-13 PREOPERATIVE FACTORS AFFECTING RADIATION TIME DURING PERCUTANEOUS NEPHROLITHOTOMY: A MULTI-INSTITUTIONAL ANALYSIS

Abstract

INTRODUCTION AND OBJECTIVES: Percutaneous nephrolithometry (PCNL) may be associated with significant ionizing radiation exposure for patients and operating room personnel. We conducted a multicenter study to assess the predictors of increased radiation exposure during PCNL. METHODS: We performed a multicenter retrospective review of patients undergoing PCNL. Patient demographics, stone characteristics and perioperative data including fluoroscopy time were recorded and analyzed. Preoperative CT images were reviewed and S.T.O.N.E. score was assigned to each patient. RESULTS: A total of 1700 patients were included in the analysis. The mean age and body mass index (BMI) were 63.4 ± 15 and 31.2 ± 7kg/m2 respectively. Mean stone size and mean overall nephrolithometry score was 3.7 and 8.3 (SD=2.2) respectively. Overall single procedure stone-free rate was 72%. In logistic regression analysis, stone size (p<0.01), number of calyces (p<0.01), BMI (p<0.01), longer procedure time (p<0.01), skin-to-stone distance (p<0.01) and S.T.O.N.E. score (p<0.01) were significantly associated with increased fluoroscopy time. Stone-free patients had statistically significant lower radiation exposure compared to patients with residual stones (8.7 vs. 16.9 minutes, respectively; P<0.001). On average, for each increase in one unit of S.T.O.N.E score, there was additional 1.5 minutes of fluoroscopy time. In risk stratification, low-risk patients with 5-7 scores had 7.8 minutes of fluoroscopy time, compared to medium-risk (8-10) and high-risk patients (11-13) who had 12.8 and 15.8 minutes of fluoroscopy time, respectively (p=0.001). CONCLUSIONS: In this multicenter study, patients with greater stone size, BMI, number of calyces, skin-to-stone distance and S.T.O.N.E. nephrolithometry were associated with increased radiation exposure during PCNL. Alternative modified pulsed fluoroscopy techniques or radiation-free imaging modalities such as ultrasound should be used in order to reduce the amount of ionizing radiation during the PCNL procedures.