Kidney stone disease is a common condition, and retrograde intrarenal surgery (RIRS) is a minimally invasive procedure frequently used to remove kidney stones. During RIRS, pressure inside the kidney can increase, which may contribute to temporary kidney injury. New aspiration-enabled access sheath systems have been developed to better control this pressure by continuously removing irrigation fluid during surgery. This study will compare aspiration and conventional access sheath systems to determine whether improved pressure control reduces early kidney injury. Blood and urine biomarkers (IL-18 and L-FABP), which can detect kidney damage earlier than standard kidney function tests, will be measured before and after surgery. The results may help identify surgical techniques that better protect kidney function and improve the safety of kidney stone treatment for patients.