Differences in Urine NGAL Levels in Patients Undergoing RIRS With or Without Ureteral Access Sheath

Differences in Urine Neutrophil Gelatinase-Associated Lipocalin (NGAL) Levels in Patients Undergoing Retrograde Intrarenal Surgery (RIRS) With or Without Ureteral Access Sheath (UAS)

This study will include patients aged between 18 and 65 who will undergo retrograde infrarenal surgery (RIRS) due to renal stone(s). A total of 60 patients (male or female) will be recruited, and will be randomized into 2 groups consisting of 30 patients in each group. The first group of patients will undergo RIRS with a ureteral access sheath (UAS) positioned prior to surgery; and the second group will undergo RIRS without UAS. As use of UAS decreases the pressure in the renal pelvis during RIRS, it is aimed to evaluate whether using UAS or not affects the kidney functions. besides the routine kidney function tests, namely urea and creatinine, neutrophil gelatinase-associated lipocalin (NGAL) (a more specific and early marker of kidney function) will be used to assess the differences in the kidney functions. Preoperative blood urea and creatinine levels and urine NGAL levels will be studied for all patients. After the surgery, blood urea and creatinine levels will be again studied as well as urine NGAL levels at postoperative 2nd hour, 72nd hour and 1st week.

RIRS with ureteral access sheath: A ureteral access sheath (UAS) will be positioned into the ureter of the patient prior to the insertion of the flexible ureterorenoscope (RIRS).

RIRS without ureteral access sheath: A ureteral access sheath (UAS) will not be positioned into the ureter of the patient prior to the insertion of the flexible ureterorenoscope (RIRS).

Determination of any impairment in renal function when ureteral access sheath is not used during RIRS by measuring urine NGAL level.

Determination of any impairment in renal function when ureteral access sheath is not used during RIRS by measuring blood urea and creatinine levels.

Inclusion Criteria: Being between 18-65 years old Having an indication of retrograde infrarenal surgery (RIRS) due to kidney stone Exclusion Criteria: Patients with uncontrolled diabetes mellitus and diabetic nephropathy Patients with blood pressure > 140/80 mmHg despite regular use of antihypertensive agent(s) Patients with chronic kidney failure who need dialysis Patients who have had prerenal, renal or postrenal acute kidney failure 3 months or much earlier Patients who have had pyelonephritis 3 months or much earlier Patients younger than 18 years or older than 65 years Patients who have undergone a kidney surgery within the last 3 months and have abnormal kidney function tests Patients with a concomitant ureter stone who will undergo an endoscopic ureter stone treatment at the same session

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