Retrograde intrarenal surgery and mini PCNL for 10-20 mm renal stones carry similar risk of bleeding: Study

Renal stones of 10-20 mm require effective interventions that reduce complications, particularly bleeding. Traditionally, percutaneous procedures have been thought to carry a risk for higher complications, such as bleeding, compared to endoscopic approaches, such as RIRS. A lot of caregivers, though, have believed otherwise, and this study looked to determine validity of the hypothesis that the assumption is incorrect, by scoring outcomes regarding bleeding following a standardized scoring method of evaluating stone size and hardness.

Total 176 patients who had renal stones with a size between 10 and 20 mm were enrolled in the study. The Stone Management According to Size-Hardness (SMASH) score=(Hounsfield units × stone maximum size in cm)/100 was used to guide the treatment to either group A or group B.

• Group A: RIRS, (n = 90) Patients with SMASH score <15.

• Group B: mini-PCNL, (n = 86) Patients with SMASH score ≥15.

Both groups received treatment with the Cyber Ho laser. Statistical comparisons were made for preoperative characteristics, stone-free rates, complication rates, and outcomes regarding bleeding.

The key findings of the study were:

Comparable Preoperative Features:

• Mean stone size: 17.1 mm (RIRS) vs 16.8 mm (mini-PCNL) (P = 0.13).

Efficacy:

• Stone-free rate: 87.8% (RIRS) vs 95.3% (mini-PCNL) (P = 0.07).

Complication Rates:

• Overall complication rate: 14.4% (RIRS) vs 18.6% (mini-PCNL) (P = 0.09).

Bleeding Risk:

• Gross hematuria: 5.5% (RIRS) vs 8.1% (mini-PCNL) (P = 0.07).

Mean hemoglobin drop:

• Day 1: 12 g/L (RIRS) vs 17 g/L (mini-PCNL) (P = 0.06).

• Day 3: 2 g/L (RIRS) vs 3 g/L (mini-PCNL) (P = 0.21).

• No blood transfusions or renal embolizations were required.

The management of renal stones between 10 and 20 mm with RIRS and mini-PCNL seems to be equivalent in terms of efficacy and shows a very low incidence of clinically significant bleeding. Such results support the use of SMASH scores for individualized selection of the best treatment for the patient.

Reference:

Perri, D., Besana, U., Maltagliati, M., Pacchetti, A., Calcagnile, T., Pastore, A. L., Romero-Otero, J., Micali, S., Govorov, A., Somani, B., Liatsikos, E., Knoll, T., Rocco, B., & Bozzini, G. (2024b). Risk of bleeding after retrograde intrarenal surgery vs miniaturised percutaneous nephrolithotomy for 10-20 mm renal stones: a not so different safety profile. BJU International. https://doi.org/10.1111/bju.16585