The Predictive Factors for the Longer Survival of the Reusable Flexible Ureterorenoscopy.

Abstract

The flexible ureterorenoscopy (FURS) is expensive and fragile equipment which easily break down during the surgery. f-URS have yet some problems with their durability that affect survival. One of the most important ways to increase the survival of a device is to improve its use in the right indications. We aimed to investigate whether the durability of the f-URS will be affected due to the volume and location of the stone and some anatomical features of the including infundibulopelvic angle (IPA), and location anomalies. The collected data from 705 patients' data including their age, sex, stone location, and stone volume, S-ReSC score, Hounsfield unit (HU) as stone density, IPA, BMI, and the usage time of f-URS using 10f-URS were included to study. Exp(B) values and confidence intervals (95% CIs) of parameters were calculated with COX regression and Roc curve analysis was also used to determine the cut-off value. Renal malformation, DJstent use, previous ESL application, and UAS use did not affect contrary to expectations stone volume, HU, IPA, and S-ReSC score were among the factors statistically significant affecting the durability of the device. It was observed, Exp(B) values of the affecting factors to be 0.984, 0.268, 0.894, and 0.607, respectively. We found the most appropriate cutoff value for IPA as 41.25 degrees. The mean stone volume broken by each of the subsequent f-URS may increase, while the mean operative time may decrease as time progresses. This result shows us the importance of mastery of the device, such as the deflection maneuver, and the correct use distance of the laser, which improves with the increase in user experience, and makes us interpret that the operation time is shortened with this self-confidence. Factors including stone volume, HU, IPA, S-ReSC score affect the durability of the f-URS device and the as well as manufacturing features.