Ciprofloxacin Prophylaxis in Retrograde Intrarenal Surgery: a Prospective Randomized Trail in Comparison of Multiple-, Single- and Zero-dose.

PURPOSE:

To compare multiple-, single-, zero-dose antibiotic prophylaxis for retrograde intrarenal surgery (RIRS) and detect the ideal regimen to prevent systemic inflammatory response syndrome (SIRS).

METHODS:

An α error of 5% and a power of 80% were assumed to detect a 14.9% difference in rates of postoperative SIRS (5.1% for the antibiotic prophylaxis group and 20% for the control group) based on the historical data. According to sample size calculation formula for comparing rates between multiple independent samples, n=2λ/(2sin-1√Pmax-2sin-1√Pmin)2,the minimum sample sizes to detect statistically significant differences were estimated to be 86 patients for each of the study groups. To account for patients lost to follow-up and study withdrawals, this number was increased to 100.

After finishing the cases mentioned above, we find the difference in rates of postoperative SIRS in our center is 7.9% (1.2% for the antibiotic prophylaxis group and 9.1% for the control group). According to sample size calculation formula, the minimum sample sizes were estimated to be 124, additional 38 patients are required to be added to each group. For the accuracy and availability of the trial, we decided to enlarge the sample size.To account for patients lost to follow-up and study withdrawals, this number was increased to 150.