It is aimed to evaluate the treatment results, rates of success and complications, and injury given to the kidney by measuring preoperative and postoperative blood and Cystatin C levels in patients with kidney stones smaller than 2 cm who will undergo either ultra-mini percutaneous nephrolithotripsy (PCNL) or micro PCNL.

In this study, the demographic and preoperative data, imaging data, operative data and postoperative follow-up data will be prospectively recorded according to the patient information forms for the patients with kidney stone smaller than 2 cm who will undergo either ultra-mini PCNL or micro PCNL.

A total of 60 (sixty) patients, aging between 18 and 65 years, with similar stone size and location are being planned to be enrolled into the study; and will be prospectively randomized into two groups with a 1:1 ratio, thus 30 (thirty) patients will receive ultra-mini PCNL while 30 (thirty) patients will undergo micro PCNL.

Preoperatively, blood and urine Cystatin C levels will be measured. After the surgery, blood and urine Cystatin C levels at postoperative 12th hour will be recorded. Besides these, classical kidney function tests, namely blood urea and creatinine levels, will be measured preoperatively and postoperatively.

Parameters listed below will be also recorded and evaluated:

1. Preoperative general evaluation data: Age, height, weight, body-mass index, concomitant comorbidities, prescriptions used, history of operation(s), American Society of Anesthesiologists (ASA) score
2. Preoperative urological evaluation data: History of extracorporeal shock wave lithotripsy (ESWL)/PCNL/ureterorenoscopy (URS)/retrograde intrarenal surgery (RIRS)/open surgery, whole blood count, kidney function tests, automatic urine test, urine culture, preoperative imaging modality (KUB, US, CT), number-dimensions-localization-composition of stone(s), existence of hydronephrosis
3. Operative data: Access fluoroscopy duration, total access duration, total fluoroscopy duration, operation duration, use of double-J stent, preoperative complications
4. Number of previous ESWL seance, total duration of ESWL, number of shots during ESWL (if any)
5. Follow-up data: Urethral catheterization time, hospitalization time, need of any other treatment for being stone-free, time to full stone-free, duration to removal of double-J stent, existence of residual stone(s), formation of new stone(s), complications in late period

Inclusion Criteria:

• Patients who are planned to undergo PCNL due to kidney stone
• Patients with a kidney stone < 2 cm
• Patients between 18 and 65 years old

Exclusion Criteria:

• Patients with unregulated diabetes mellitus and diabetic nephropathy
• Patients with a blood pressure higher than 140/80 mmHg despite use of antihypertensive drug(s) regularly
• Patients with chronic renal failure who need dialysis
• Patients who had prerenal, renal or postrenal acute kidney failure during the last 6 months
• Patients who had acute pyelonephritis during the last 6 months
• Patients younger than 18 years old or older than 65 years old
• Patients who had kidney surgery during the last 3 months and who have abnormal kidney functions
• Patients with ureteral stone who are planned to undergo endoscopic stone treatment at the same time
• Patients with a history of corticosteroid use during enrollment into the study or previous 3 months
• Patients with uncontrolled thyroid disease
• Patients who have a disease with rapid cell turn-over (like leukemia, lymphoma, etc.)
• Patients whose operation terminated or converted to open surgery due to any reason
• Patients with missing data