What is the role of ureteroscopy in the treatment of nephrolithiasis?

Updated: Jun 21, 2018
  • Author: Chirag N Dave, MD; Chief Editor: Bradley Fields Schwartz, DO, FACS  more...
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Answer

Along with ESWL, ureteroscopic manipulation of a stone (see the image below) is a commonly applied method of stone removal. A small endoscope, which may be rigid, semirigid, or flexible, is passed into the bladder and up the ureter to directly visualize the stone. Normal saline should be used for this procedure, as opposed to sterile water, to prevent electrolyte disturbances and hemolysis. [41]

Two calculi in a dependent calyx of the kidney (lo Two calculi in a dependent calyx of the kidney (lower pole) visualized through a flexible fiberoptic ureteroscope. In another location, these calculi might have been treated with extracorporeal shockwave lithotripsy (ESWL), but, after being counseled regarding the lower success rate of ESWL for stones in a dependent location, the patient elected ureteroscopy. Note that the image provided by fiberoptics, although still acceptable, is inferior to that provided by the rod-lens optics of the rigid ureteroscope in the previous picture.

Ureteroscopy is especially suitable for removal of stones that are 1-2 cm, lodged in the lower calyx or below, cystine stones, and high attenuation ("hard") stones. It is also useful in patients who have multiple small calculi or pre-existing nephrostomy tubes, and following a UTI. The typical patient has acute symptoms caused by a distal ureteral stone, usually measuring 5-8 mm.

Stones smaller than 5 mm in diameter generally are retrieved using a stone basket, whereas tightly impacted stones or those larger than 5 mm are manipulated proximally for ESWL or are fragmented using an endoscopic direct-contact fragmentation device or a holmium laser fiber. Stones can then be retrieved by stone basket and/or allowed to pass spontaneously.

When attempting to achieve a high stone-free rate, a surgeon can take one of two general approaches: 1) complete fragment retrieval via stone basket or 2) exhaustive lithotripsy to allow for residual stones to pass spontaneously. In large studies comparing those two approaches, the former has been associated with higher stone-free rates (up to 100% versus 87%), lower rates of subsequent unplanned emergency department visits, and lower rates of re-hospitalization.

An additional intervention,  to prevent migration back into the renal pelvis, is placement of a backstop device proximal to the stone, prior to fragmentation. This has been shown to lead to higher stone-free rates, fewer emergency room visits, and lower hospitalization rates, when compared with cases in which the backstop is not used.{ref76)


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