Results:
A total of 575 patients were enrolled into the study. The demographic characteristics and results of groups in terms of the OT, infection status and the UAS usage were summarized in Table 1, 2 and 3, respectively.
According to the analysis with regard to the OT; age, sex, BMI, stone density, and stone free rates were similar between the groups whose operation time was less than 60 minutes and the group longer than 60 minutes. As expected, stone size and stone surface area was larger statistically, than in the group whose OT was longer than 60 minutes (p<0.05, Table 1). The rate of the usage UAS was greater statistically in the group whose OT was longer than 60 minutes (p<0.05, Table 1). In addition, infection rates in the group whose OT was longer than 60 min was higher statistically than in the group whose OT was lesser than 60 min ( p<0.05, Table 1).
According to the analysis with regard to the infection status; age, sex, stone size, stone surface area, localisation of the stones were not statistically different between the group with the infection and the group without the infection, but the OT was longer statistically in the group with the infection than in the group without the infection ( 94.1±14.2 and 68.01±23.1, for the group 1 and 2, respectively, p<0.05, Table 2).
According to the analysis with regard to the usage of the UAS; age, sex, stone size, stone surface area, stone free rates, and infection rates were not statistically significant between the group in which the UAS was used and the group not used, however, the OT was statistically longer in the group in which the UAS was used than in the group in which the sheath was not used ( 79.3±24.4 and 66.7±22.4, for group 1 and 2, respectively, p<0.05, Table 3).
Logistic regression analysis revealed that OT is an independent risk factor for infective process (Table 4). The analysis of ROC curve to estimate the sensitivity and specificity of OT in predicting infectious events determined the cut-off point as 87.5min. The area under curve (AUC) for OT time in terms of the infection risk was 0.82 (sensitivity 89.3%, specificity 69.5%, 95% CI 0.77-0.88; p=0.000) (Fig.1) (Table 5).