Limitations
This study has certain limitations. First, it was a retrospective study and had a small number of patients. Second, the chemical analysis of the stones was not undertaken. Third, stone cultures were not included in the study. Although the effect of PAP and preoperative antimicrobial treatment remains uncertain, it is essential to identify high-risk patients, take an intraoperative culture, and perform infection control more carefully according to the results in order to prevent serious infection complications. Therefore, well designed prospective studies with larger case series are required to confirm the results of the current study.