We thank Dr. Hall and colleagues for their commentary on our meta-analysis clarifying the differential efficacy of tamsulosin in patients with ureteral stones. As the authors point out, the tamsulosin number needed to treat for large distal stones is 5. However, in all comers (all patients with ureteral stone, rather than the large distal stone subgroup), the number needed to treat is much less favorable. However, in general, the number needed to treat is much less favorable. An ultrasonography-first approach for suspected ureteral stones may leave clinicians with uncertainty in regard to stone size and location in some cases, which leads to a fundamental question: should clinicians use computed tomography (CT) to determine stone size and location to better identify patients who might benefit from tamsulosin?

In the meta-analysis, we sought to determine the efficacy of tamsulosin for ureteral stone, irrespective of imaging modality used to define study cohorts. However, our search of high-quality studies of tamsulosin efficacy identified only studies that enrolled participants according to CT findings; we did not identify any studies in which ultrasonography was used to select patients. Thus, in the strictest sense, our findings apply only to individuals in whom CT identified a large distal ureteral stone.

In terms of imaging selection, we believe that CT should not be routinely chosen over ultrasonography for patients with suspected ureteral stones. We agree with Dr. Hall and colleagues in advocating an ultrasonography-first strategy for patients who are not at high risk for a stone-related emergency (eg, urosepsis, renal deterioration, solitary kidney, intractable symptoms) or an important alternative diagnosis, such as appendicitis. In fact, radiology ultrasonography may be accurate for large distal ureteral stones. Although less sensitive compared with CT scan, radiology ultrasonography mainly misses small stones and those in the midureter. Still, some stones might be missed with an ultrasonography-first strategy, and so the risks of radiation must be weighed against the benefit of improved detection of a large distal stone. Further studies of this strategy would help answer this question.

It may be reasonable to use tamsulosin empirically without knowing size or location, but this is a less ideal approach because the effect of tamsulosin on ureteral stones of unknown size and location would, on average, be diminished. We do not believe that the finding of moderate to severe hydronephrosis is accurate enough to select patients for tamsulosin. According to the study cited by Dr. Hall and colleagues, moderate to severe hydronephrosis has a sensitivity of 52% and specificity of 79% for a stone greater than 5 mm, and 11% of stones greater than 5 mm would be missed. Another possible strategy would be to treat regardless of ultrasonographic findings, weighing the risk of radiation exposure against the adverse effect of α-blockers, which are typically well tolerated. Again, more research is needed.

Our practice generally involves an ultrasonography-first strategy for patients with uncomplicated stone and a low risk of an alternative diagnosis. For patients who receive a diagnosis of a ureteral stone and in whom a stone is not visualized, we have begun to discuss with them the risks and benefits of tamsulosin. Many patients wish to proceed with tamsulosin without obtaining CT, although there are exceptions.