Current clinical evidence in intrarenal temperature, pressure and suction during retrograde intrarenal surgery: a review of literature

Purpose of review Experimental evidence suggests that intrarenal temperatures (IRTs) and pressures (IRPs) during retrograde intrarenal surgery (RIRS) with laser lithotripsy are clinically significant. Suction devices aim to facilitate RIRS and improve procedure outcomes. We present an overview of new clinical studies regarding IRT, IRP, and suction developments. Recent findings High laser power, low irrigation, and restricted working space were directly correlated with increased IRTs. Increased irrigation flow rate and ureteral access sheath (UAS) maintained well tolerated IRTs. Baseline IRPs ranged from 16 to 17 mmHg. Intraoperative IRP monitoring maintained values below 22 mmHg. Hand-assisted pumps often increase IRPs above the safety threshold. Prolonged IRP increments were correlated to postoperative infections. Suction devices decreased operative time to less than 60 min and improved stone-free rates (SFRs) at 1 day to more than 80 and at 30 days to more than 90%. Summary Despite the limited clinical evidence, IRTs during RIRS correlate directly with laser power and reversely correlate with irrigation flow rate and UAS use. Intraoperative IRP monitoring prevents hazardous increments. Manual pump irrigation causes extremely high IRPs. There is a possible relation between prolonged IRP increments and infectious complication development. Using suction UAS or flexible and navigable sheaths (FANS) improves operative times and SFRs, while more studies regarding direct in-scope suction (DISS) efficiency and safety are needed.