Does stone analysis have better predictive value than urine culture and stone culture for predicting systemic inflammatory response syndrome post retrograde intra renal surgery? A single center pilot study

Purpose: Infective complications such as fever, systemic inflammatory response syndrome (SIRS), septicemia, and shock are common and preventable complications after retrograde intrarenal surgery (RIRS). Patients with positive urine and stone cultures have a greater risk of SIRS. Infection stones (carbonate apatite) are bacteria-harboring stones that predispose to sepsis. A pilot study is conducted to establish the role of stone analysis in predicting SIRS after RIRS compared to urine and stone cultures. Materials and Methods: Sixty patients who underwent RIRS from January 2018 to June 2018 were prospectively evaluated with respect to preoperative urine culture, stone burden and location, operative time, postoperative clinical course, residual stone size, stone culture, stone analysis, and occurrence of septicemia-related events. Results: 5 out of 60 patients who underwent RIRS developed SIRS (8%). Sensitivity levels of predicting SIRS were different, where urine culture (20%), stone culture (20%), and carbonate apatite on the stone analysis (60%). Positive urine culture and stone culture had no significant relation to the prediction of SIRS (P = 1). Carbonate apatite was present in 12 samples (20%) in varying proportions. The presence of apatite >50% of the total sample was in 5/60 samples (8%), which are referred to as infection stones. Three out of these 5 patients with infection stones developed SIRS (60%). Thus, the presence of carbonate apatite in the stone analysis had a statistically significant relation to SIRS (P 50% on stone analysis has higher sensitivity than urine and stone culture in predicting SIRS after RIRS.