The Effect of Three Endourological Procedures for the Management of Renal Calculi Regarding Acute Kidney Injury

The main aim of the study is to investigate and compare the possible acute effect of standard PCNL, mini-PCNL and RIRS on renal function. Secondary aims are to investigate the efficacy (stone-free rate), safety (complication rate, long-term kidney function) and other parameters (operation, fluoroscopy and hospitalization time) concerning the 3 endourological operations (PCNL, mini- PCNL, RIRS) for the treatment of renal calculi.

This is a 3-arm parallel group prospective randomized active-treatment clinical study. A total of 75 patients with renal calculi 10-30 mm in maximal diameter measured in abdominal CT scan will be recruited in this research protocol. Patient enrollment will be performed from patients referred to Urolithiasis Unit of the 1st Urology Department, G. Gennimatas Hospital, Aristotle University of Thessaloniki. In all potentially eligible patients full medical history, as well as demographic characteristics and drug treatment will be recorded, followed by a detailed physical examination and standard laboratory tests.

Eligible patients will be randomized to receive one of the following endourological techniques of nephrolithotripsy: standard PCNL, mini- PCNL or RIRS. All eligible patients will be randomised to one of the 3 groups, consisting of 25 patients, with an equal allocation ratio (1:1). The randomization sequence will be computer generated by the study coordinating team.

The primary and secondary measurements of the study will be carried in prespecified time-points that are listed below:

Point 0(P0): Screening visit:

Potentially eligible patients will be asked to provide written informed consent. We will record full medical history, concomitant medication, clinical examination, demographic characteristics, body weight, height, body mass index (BMI).

Point 1(P1): 1st day of hospitalization (Monday or Thursday):

Admission of the patient to the hospital where a routine preoperative control is conducted including: routine hematological and biochemical laboratory parameters (Hct, Hb, WBC, PLT, fasting glucose, urea, creatinine, serum electrolytes, SGOT, SGPT), chest X-ray and anesthesiological preoperative evaluation. Patient is randomized to be treated with one of the 3 endourological operations.

Point 2(P2): Operation day (Tuesday or Friday), 2 hours before the operation:

Urine sample is collected for measurement of urine biomarkers (NGAL, KIM-1, IL-18) and creatinine (baseline values). Blood sample is collected for creatinine measurement and eGFR is calculated.

Point 3(P3): Operation (PCNL, mini-PCNL or RIRS):

Operation, fluoroscopy time and intraoperative complications are recorded

Point 4(P4): 2 hours after the operation:

Urine sample is collected for measurement of urine biomarkers (NGAL, KIM-1, IL-18) and creatinine. Blood sample is collected for creatinine measurement and eGFR is calculated. A VAS pain score is completed. Urine output is measured. Postoperative complications are recorded.

Point 5(P5): 6 hours after the operation:

Urine sample is collected for measurement of urine biomarkers (NGAL, KIM-1, IL-18) and creatinine. Blood sample is collected for creatinine measurement and eGFR is calculated. A VAS pain score is completed. Urine output is measured. Postoperative complications are recorded.

Point 6(P6): 24 hours after the operation:

Urine sample is collected for measurement of urine biomarkers (NGAL, KIM-1, IL-18) and creatinine. Blood sample is collected for creatinine measurement and eGFR is calculated. A VAS pain score is completed. Urine output is measured. Postoperative complications are recorded.

Point 7(P7): 48 hours after the operation:

Urine sample is collected for measurement of urine biomarkers (NGAL, KIM-1, IL-18) and creatinine. Blood sample is collected for creatinine measurement and eGFR is calculated. A VAS pain score is completed. Urine output is measured. Potential postoperative complications are recorded.

Point 8(P8): 1 month after the operation:

CT scan is conducted for confirmation of treatment success and stone free status or not. Blood sample is collected for creatinine measurement and eGFR is calculated. Potential postoperative complications are recorded.

Point9(P9): 3 months after the operation:

Blood sample is collected for creatinine measurement and eGFR is calculated. Potential postoperative complications are recorded.

Eligibility Criteria:
Inclusion Criteria:

1. Patients aged \> 18 years old
2. Patients with renal stone or stones of 10-30 mm in maximal diameter measured in computed tomography scan.
3. Decision of the patient to receive surgical treatment
4. Ability to understand and provide a written informed consent to participate in the study.

Exclusion Criteria:

1. Solitary kidney (functional or organic)
2. Ureteral stone in the same system causing obstruction
3. Malignant tumor in the treated kidney
4. Stone in diverticulum
5. Diabetes or coronary heart disease.
6. History of surgery in the treated kidney
7. Recent intake of drugs that affect renal function or intravenous contrast agent
8. Concomitant urinary infection
9. Congenital anomalies of the urinary tract
10. Patients of whom incomplete clinical data or incomplete samples are available