Abstract
Danilovic et al. communicated an article addressing bilateral retrograde intrarenal surgery (RIRS) for kidney stones. 1 The rationale for this approach relies on factors such as cost reduction, avoiding a second procedure, and reducing surgical waiting list, among others.
A historical concern for potential acute renal injury and the alleged higher complications rate caused by the simultaneous manipulation of kidneys has driven surgeon's choice toward staged procedures. Nevertheless, through our prospectively collected experience 2,3 and systematic review, we have demonstrated bilateral RIRS and percutaneous nephrolithotomy are both effective and safe procedures. 4
Agreeing with authors, there is a lack of well-conducted studies, and best quality evidence would be reached through a clinical trial comparing patients with bilateral stones randomly allocated for RIRS whether as a bilateral same session procedure or to two-staged procedures.
Conversely, researchers compared unilateral versus bilateral RIRS and found a similar stone-free rate and hospital stay, whereas bilateral RIRS utilized fewer supplies and had longer operative time. The way these results are reported could be misleading: it should be stressed that overall hospitalization must be obtained by adding also that of the second side. Similarly, the longer operative time for bilateral RIRS (61.24 vs 88.65 min) may lead to misinterpretation, as theater time per renal unit definitely favors bilateral RIRS (61.24 vs 44.3 min).
Regarding complications, our view is different from that of the authors, who concluded bilateral RIRS was “not entirely safe.” This statement is biased by the perception that the risk of complications doubles that of staged procedures. On the contrary, it is clear how overall risk is essentially equivalent, and mainly determined by the number of renal units treated. In other words, in staged treatment, the risk of complications is diffused over time rather than being faced at once when bilateral procedure.
In fact, the higher complication rate (15.9% vs 39.9%) and emergency department visits (11.6% vs 34.8%) are again biased by the fact that a bilateral procedure is being compared with a single-side one. Moreover, all complications but one, were Clavien Dindo I–II, and the only IIIb happened in the bilateral group where a patient underwent bilateral stenting. Noteworthy, a high rate of JJ stent displacement before planed was reported (34.8%–39.1%) probably because of the consistent use of stent-strings, which is not recommended in bilateral cases. This was definitely an avoidable complication.
Similarly, the authors reported a higher creatinine increase for bilateral RIRS. Interestingly, bilateral group's baseline creatinine had a wide standard deviation (0.97 ± 0.59; 60% of the mean) arising concern on data distribution. It may have been better using nonparametric data. However, at postoperative day 90, creatinine levels were comparable, and all follow-up means were within normal range. Also, a change-from-baseline would have been more informative. Nonetheless, this relevant finding invites us to proper patient selection, namely normal kidney function.
As clinical trials are warranted, we believe that, to date, evidence spots safety of bilateral RIRS along with shorter operative and anesthesia time, and hospitalization, which can benefit both, patients and health care providers.