Editing CUA: Ureteral Calculi (2015) (section)

== URS ==

* '''Common methods of intracorporeal ureteroscopic lithotripsy include pneumatic, eletrohydraulic, and Holmium:YAG (Ho:YAG) laser. Of these,''' '''Holmium:YAG is the method of choice''' in terms of stone fragmentation, stone free rates, and need for auxiliary procedures.
* '''Use of a ureteral access sheath has traditionally been advocated at the time of flexible URS for renal stones for several reasons, including (4):'''
*# '''Allowing easy multiple entry and re-entry to the upper urinary tract and renal collecting system'''
*# '''Decrease in intrarenal pressure, which could potentially diminish kidney injury'''
*# '''Improved irrigation flow thus optimizing vision'''
*# '''The potential to improve stone-free rates by allowing passive egress or active retrieval of fragments'''.
** However, evidence is very limited
* Semi-rigid ureteroscopes represent the mainstay for treating most ureteric stones due to (3):
*# Superior optics
*# Excellent irrigant flow
*# Size of the working channel.
* The outer tip diameter of ureteroscopes typically varies between 4.5 and 8.5Fr. for semi-rigid ureteroscopes and 6.75 to 8.7Fr. for flexible ureteroscopes. Digital flexible ureteroscopes are bigger (8.7Fr. tip with 9.9Fr. shaft)
* '''Preoperative discussion should include the potential of failed access, placement of a ureteral stent, and delayed URS at another date'''
* '''Stenting following uncomplicated URS is still a controversial topic''' and there is evidence to support both sides.
** '''If a ureteral access sheath is used during URS, a ureteral stent should be placed.'''
** '''If bilateral URS is performed, depending on the situation, consideration should be given to stenting at least one side, to prevent the possibility of bilateral ureteric obstruction postoperatively.'''
** '''Stenting does not affect stone-free rates or long-term complications such as strictures, but may result in less emergency room visits and narcotic use in the postoperative period'''
** '''Stenting prior to URS is helpful to improve stone-free rates in stones > 1 cm. Stenting prior to URS also facilitates access to the ureter due to passive dilation'''