The Use of the "Comprehensive Complication Index" as a Recording System of Postoperative Complications After Percutaneous, Retrograde and Extracorporeal Lithotripsy for Renal Lithiasis.

The study will be prospective non-interventional and will include patients with kidney stones who are to undergo one of the following three techniques: retrograde nephrolithotripsy, percutaneous nephrolithotripsy and extracorporeal nephrolithotripsy depending on the size of the stone. The study will take place at the 2nd Urology Clinic of the University of Athens, at the Sismanoglio Hospital of Athens. It will include patients diagnosed with kidney stones after plain X-ray and/or CT scan. Percutaneous nephrolithotripsy will be performed on stones > 2 cm, while extracorporeal or retrograde nephrolithotripsy on stones < 2 cm. Patient demographics (age, gender, body mass index, comorbidities, anticoagulant use), stone-related data (maximum stone size, anatomic location of stone, number of stones, presence of hydronephrosis preoperatively, presence of piglet catheter preoperatively, positive urine culture, preoperative chemoprophylaxis ) as well as information about the operation (type of anesthesia, operation time, hospitalization time) will be reported. Finally, all possible complications will be recorded intraoperatively, immediately postoperatively and up to 30 days after the day of surgery. This will be followed by a statistical analysis of the resulting data and a comparison between the CDC and CCI systems using the SPSS statistical program. To describe continuous variables, the mean/standard deviation will be used if it is a normal distribution, or the median and range if it is a non-normal distribution. The Shapiro-Wilk test will be used to investigate the distribution of the data. The absolute number and the corresponding percentage will be used to describe the qualitative variables. For the comparison of continuous variables, the parametric t-test will be used if the data follow a normal distribution, or the Mann-Whitney U test if they do not follow a normal distribution. Chi-square and Fisher's exact test will be used to compare qualitative variables. Exclusion criteria from this study are:

1. Non-acceptance by the patient of his participation or inability to understand the purposes and procedures of the study.
2. Recent similar operation that the patient has undergone (interval of less than one month).