The options for management of ureteral stones include conservative approaches such as active monitoring, and MET, minimally invasive procedures such as shock wave lithotripsy (SWL) and URS, and less often, laparoscopic ureterolithotomy. Taking together the observed rates of spontaneous stone passage, and variable time frame with which stones pass, the timing of when and modality with which to intervene can be challenging. Several factors, including patient preference, stone burden and location, resource availability, and surgeon skill, all contribute to the chosen treatment approach. Although conservative approaches such as observation or MET are acceptable options, passage of stones with such approaches may take several weeks to occur, during which period, patients may remain symptomatic, requiring ER visits, hospital admission, and analgesic use. Interestingly, despite its proven role in promoting stone passage, MET is still rarely used at the primary care level [19, 23]. In select cases, it might be prudent to offer early definitive therapy after a thorough discussion with the patient.

The indications and recommendations for URS have changed over the years, and is largely attributable to the refinement of flexible and rigid ureteroscopes, improved optics and ancillary instruments such as laser fibers and baskets, and to an extent evolution of surgical technique. Also, SWL has proven to be less effective than once thought. The updated ureteral stone guidelines reflect these changes, with an expansion for the indications of URS in treating ureteral stones [6]. While no differences in overall SFR were found between SWL and URS, the only instance in which SWL yielded slightly higher SFR was for proximal ureteral stones ≤10 mm. URS had significantly higher SFR for proximal stones >10 mm and for distal ureteral stones of all sizes. For all mid-ureteral stones, URS trended towards superior results but did not reach statistical significance. Such outcomes data would indicate that URS is perhaps less affected by stone burden than is SWL [24], and for obvious reasons, i.e., with SWL, the larger the stone burden, the more fragments that need to pass. URS is now deemed appropriate as first-line therapy for stones of any size in the proximal ureter, with clear benefits for stones >10 mm. Consistent with this is the updated Cochrane review comparing SWL to ureteroscopic management of ureteral calculi, which evaluated data from 7 randomized controlled trials. The authors report lower SFR (RR 0.84) and higher retreatment rates (RR 6.18) with SWL compared to URS, but with the benefit of shorter hospital stay and fewer complications (RR 0.43) [25]. This was further illustrated by Raman et al., where the number of primary procedures (i.e., the intended treatment modality) was fewer for URS compared to SWL at all ureteral locations, indicating a higher retreatment rate for SWL [24]. Scales and colleagues showed in a recent analysis that the odds of a second procedure following initial SWL were 1.54 times those of URS [26]. In their review, they showed that in beneficiaries undergoing initial SWL, 38% underwent an additional procedure within 120 days, versus 9% for URS and 18% for URS plus holmium laser.

Although the 1997 ureteral stone guidelines recommended SWL for stones <10 mm and either SWL or URS for stones >10 mm in the proximal ureter, the current guidelines, along with more recent data, reflect a change in this assertion. This shift in outcomes is largely due to improved endoscopic technology as discussed earlier, rendering URS easier and safer. Furthermore, newer devices such as the Stone Cone (Microvasive; Boston Scientific Corp., Spencer, IN) and N-Trap (Cook Urological, Spencer, IN) to prevent stone retropulsion during proximal URS may further contribute to the improved results [27, 28].

Unfortunately, it is very difficult to draw direct comparisons between available studies due to the variability in methodologies and criteria for determining SFRs; this continues to affect newer literature as well, as outlined in the Cochrane review discussed above. The limitations in assessing the currently available literature on SWL and URS stem from the lack of standardization in comparing stone size and burden, and more universal criteria in future study designs might permit a more accurate standard of comparison [20].

In a recent review of over 9,000 beneficiaries in the USA who underwent an initial procedure for the treatment of ureteral stones, several patients, providers, and practice setting characteristics were associated with the selection of URS versus SWL [26]. As might be expected, the odds of undergoing URS was 44% higher when treated at a high-volume URS facility versus 68% lower odds when treated at a high-volume SWL facility. A significant and interesting finding in this review was that female patients were less likely than males to undergo URS. Such gender-based preferences for the treatment modality for ureteral stones may have subtle clinical implications, in light of the observed trend of higher rate of increase in the incidence of stone disease in women compared to men. Congruent with these findings was a study that showed more recently that trained urologists were more likely to use URS than SWL, based on an analysis of board certification logs [29]. Leijte et al. showed that surgeon experience was indeed a predictive factor for complications and success for ureteroscopic holmium laser lithotripsy for ureteric calculi. Experienced surgeons had fewer complications, and the success rate was higher [30]. Nonetheless, current practice patterns indicate a consistent trend among American urologists towards URS and away from SWL for the management of stones of all sizes throughout the ureter [31]. For example, even with an expansion of extracorporeal lithotripter ownership in the state of Michigan, an associated drop in the rate of URS was not seen [32].

A cost–benefit analysis showed that, after failed observation, URS is the most cost-effective treatment strategy for ureteral stones at all locations [33]. Although observation alone is purported to be more cost-effective than surgical treatment, costs of total observation are more difficult to ascertain as the observation regimen is less controlled due to variations in management, with variable hospital ER visits, loss of work secondary to pain, etc. Cumulative economic data suggest that URS is the most cost-effective treatment strategy for ureteral stones in all locations, after observation fails [34].