Ahmed AF. et al., 2025: Retrograde intrarenal surgery for treatment of stones in congenital anomalous kidneys: a case-matched comparative study with extracorporeal shockwave lithotripsy.

Abul-Fotouh Ahmed, Mahmoud ElMesery, Mohamed Algammal, Abdullah Daoud, Ahmed Solyman, Ahmed Mosaad 
Urolithiasis. 2025 Oct 6;53(1):188. doi: 10.1007/s00240-025-01860-8. 

Abstract

Objectives: To compare the efficacy and safety of extracorporeal shockwave lithotripsy (SWL) and retrograde intrarenal surgery (RIRS) in the management of renal stones in patients with congenital renal anomalies.

Methods: In this matched-group comparative study, we prospectively enrolled patients with congenital renal anomalies and renal stones ≤ 20 mm who underwent RIRS. These patients were matched 1:1 with those who underwent SWL at our institution. The primary outcome was the stone-free rate (SFR). Secondary outcomes included operative time, fluoroscopy time, complication rates, hospital stay, and need for retreatment.

Results: A total of 166 patients were included (83 in each group). Baseline demographic, clinical, and stone characteristics were comparable between the two groups, except that patients in the RIRS group had significantly higher BMI and stone radiodensity. The distribution of anomalies was as follows: malrotation (79.5%), horseshoe kidney (6.0%), pelvic kidney (10.8%), duplex system (2.4%), and crossed renal ectopia (1.2%). RIRS achieved a significantly higher SFR than SWL (81.9% vs. 56.6%, p < 0.001). Complication rates were comparable between the groups (RIRS: 24.1%, SWL: 20.5%), with the majority being minor (Clavien–Dindo grade I–II). RIRS was associated with a longer operative time, shorter fluoroscopy exposure, and significantly lower retreatment rates (19.3% vs. 85.5%, p < 0.001). The median hospital stay was 2 days for RIRS, while SWL was performed on an outpatient basis.

Conclusion: In patients with congenital renal anomalies, RIRS provides superior stone clearance and significantly reduces the need for retreatment compared to SWL, while maintaining a comparable safety profile.

Trial registration: The trial was registered at ClinicalTrials.gov (NCT05240170) (04/02/2022).

Comment Hans-Göran Tiselius

Stone removal from anomalous kidneys is a tricky procedure because of complex clearance of fragments. The authors of this study addressed the problem by matched comparisons. They accordingly included in the comparison patients with up to 20 mm large stones treated with RIRS and stones with similar anomalies treated with SWL. The RIRS patients were included prospectively whereas the SWL patients were historical.
Although the selection of patients allowed for a reasonable comparison the problem is that the results of SWL were known by the surgeons doing RIRS. Although this situation is less than optimal, it is to some extent compensated for by the large number of patients in the study.
The overall initial stone-free rates were 72% for RIRS and 57% for SWL. This result is expected in view of the direct manipulation of stones under vision in RIRS.
From an economic point of view, it is noteworthy that the cost for RIRS was approximately twice that of SWL.
Although the two groups both comprise patients with anomalous kidney anatomy, a careful comparison of patients with identical or close to identical anatomical conditions would have been more rewarding.

Hans-Göran Tiselius