Intrarenal access with the flexible ureteropyeloscope: effects of active and passive tip deflection

In flexible ureteroscopy, active deflection of the tip of the endoscope is essential to reach the lateral and inferior infundibula. Two other features may affect endoscope function: one- or two-way deflection and the presence of a secondary, passively deflectable, segment. In our 7-year experience with five different endoscopes, attempts to examine the intrarenal collecting system were successful in 205 of 225 patients (92%). The success rate was lowest with a prototype endoscope, which did not have a secondary deflecting segment. There was no significant difference between those instruments with single- or two-way deflection that possessed secondary deflection. Endoscopes with secondary deflection were most successful in entering the lower pole, and this feature was necessary to reach the entire collecting system in 51% of the patients. Most of the failures of access were in attempts to reach the lower infundibulum. There was some trend toward greater success with the smaller instruments (8.5F).