Cold saline irrigation, a novel approach, reduces the risk of postoperative urinary tract infection in retrograde intrarenal surgery

Retrograde intrarenal surgery is a standard treatment for upper urinary tract stones. However, serious postoperative urinary tract infections are frequently experienced. In this study, we hypothesized that vasoconstriction caused by kidney cooling might reduce the risk of bleeding and infection during retrograde intrarenal surgery. We retrospectively analyzed 139 patients who underwent RIRS for the treatment of renal and ureteral stones at the Japanese Red Cross Hadano Hospital in Kanagawa Prefecture. Patients were classified into two groups: the HOT group in which intraoperative irrigation was performed using saline solution heated to 37°C, and the COLD group in which saline solution cooled to 4°C. The incidence of urinary tract infection after surgery was significantly lower in the COLD group (7.4%) than in the HOT group (19.7%). The length of hospital stay was also shorter in the COLD group than in the HOT group. Our results suggest that intraoperative irrigation with cooled saline may reduce the risk of perioperative UTI.