Flexible ureterorenoscopy versus extracorporeal shock wave lithotripsy for treatment of lower pole stones of 10-20 mm

What's known on the subject? and What does the study add? Shock wave lithotripsy and flexible ureterorenoscopy are acceptable treatment options for lower pole stones smaller than 10 mm, while percutaneous nephrolithotomy is the favoured treatment for stones larger than 20 mm. For treatment of lower pole stones of 10-20 mm, flexible ureterorenoscopy has a significantly higher stone-free rate and lower retreatment rate than shock wave lithotripsy.

Objective: To compare the outcomes of flexible ureterorenoscopy (F-URS) and extracorporeal shock wave lithotripsy (ESWL) for treatment of lower pole stones of 10-20 mm.

Patients and methods: The database of patients with a single lower pole stone of 10-20 mm was examined to obtain two matched groups who were treated with F-URS or ESWL. Matching criteria were stone length, side and patient gender. Stone-free rates were evaluated 3 months after the last treatment session by non-contrast computed tomography. Both groups were compared for retreatment rate, complications and stone-free rate.

Results: The matched groups included 37 patients who underwent F-URS and 62 patients who underwent ESWL. Retreatment rate was significantly higher for ESWL (60% vs 8%, P < 0.001). Complications were more after F-URS (13.5% vs 4.8%), but the difference was not significant (P= 0.146). All complications were grade II or IIIa on modified Clavien classification. The stone-free rate was significantly better after F-URS (86.5% vs 67.7%, P= 0.038). One failure of F-URS (2.7%) and five failures (8%) of ESWL were treated with percutaneous nephrolithotomy. Significant residual fragments in three patients (8%) after F-URS were treated with ESWL, while significant residual fragments after ESWL in five patients (8%) were treated with F-URS. Residual fragments (<4 mm) were followed every 3 months in one patient (2.7%) after F-URS and in 10 patients (16%) after ESWL.

Conclusions: For treatment of lower pole stones of 10-20 mm, F-URS provided significantly higher stone-free rate and lower retreatment rate compared with ESWL. The incidence of complications after F-URS was not significantly more than after ESWL.