In general, guidelines based on evidence-based medicine and created by a recognized panel of experts in a given field are important for establishing an accepted standard of care. For the medical and surgical management of urolithiasis, several different guidelines have been produced by myriad urological associations. While many of the available guidelines are based on high-level evidence, there are a number of recommendations in each document that are based only on expert opinion, deemed “eminence-based medicine.”¹ Also, there are often different methodologies for assigning a grade to the levels of evidence or determining the strength of a given recommendation. For example, the American Urological Association includes strong observational studies, such as cohort studies and case-control studies, in its highest level of evidence (Grade A) along with randomized control trials (RCTs).² Conversely, the European Association of Urology (EAU) and the Canadian Urological Association (CUA) only consider meta-analyses of RCTs as the highest level of evidence.^3,4

We recently reviewed the consensus and controversy of multiple association guidelines focused on the surgical and medical management of stone disease.⁵ Areas of controversy were often caused by lower levels of evidence and the attendant default to local eminence-based medicine.

One of the major shortcomings in the reporting of stone treatments, which adversely impacts the ability to develop guidelines, is the ongoing absence of a defined standard for reporting surgical outcomes. The lack of consistency with reporting stone-free rate (SFR), which defines treatment efficacy, muddles the ability of even the most expert panel to develop reliable and consistent guidelines. In this regard the timing of followup imaging, the type of imaging done and the actual definition of SFR are confounding factors. In some cases, followup studies are done immediately while in other reports studies are delayed until 3 months postoperative to allow time for the passage of small fragments.

While it is freely acknowledged that computerized tomography (CT) is the most accurate study to assess stone-free status, many studies persist in using plain radiographs, ultrasound or both. Radiographs may miss stones in 30% to 40% of patients while ultrasonography misses up to 27% of stone remnants. The sensitivity of ultrasound improves when combined with plain radiographs, but even then 20% of patients may be improperly counseled.^6,7

Additionally, the definition of SFR varies greatly around the world. It is our contention that SFR means the absence of all targeted stones on a CT scan performed within 3 months of the procedure. With this stringent definition, it is sobering to realize that even in the best of hands, 25% to 42% of patients will have postoperative stone remnants resulting in reintervention within 2 years in nearly a third of patients.^8,9

We recommend that a grading system be applied to SFR in order to overcome the oft misused or misrepresented term of “stone free” (see Appendix). Low-dose, abdomen-only CT-based absolute SFR (Grade A) indicates the absence of any stone fragments while CT-based relative SFR has 2 possibilities: Grade B (≤2 mm fragments) and Grade C (≤4 mm fragments). A system of this nature would allow for accurate comparison of many of the currently available CT-based studies. Results based solely on plain radiographs or ultrasound would no longer be included in the evidence used by the various guidelines panels to develop their recommendations.

Expectedly, guidelines lag behind contemporary evidence as each new study must be evaluated and vetted by the members of each of the dedicated guideline groups. Of note, today all urological societies and associations have urolithiasis working groups. Rather than having these groups of experts work in isolated bubbles producing at times conflicting or incomplete guidelines, we firmly support the earlier proposal of Pradere and colleagues to create a collaborative international endeavor that would develop a single universal guideline.¹⁰

If we have learned anything from the current COVID-19 chaos, it is that we can meet effectively using videoconference platforms. In this manner, time zones cease to be an impediment to gathering the best and the brightest across the globe to create a universal set of guidelines that would also take into account the exigencies caused by economic constraints and resources. Such efforts by each society would significantly decrease the lag time from published evidence to wide-scale implementation, much to the benefit of all people afflicted with urolithiasis.