The success of shock wave lithotripsy (SWL) in treating moderate-sized (10–20 mm) renal stones

Many centres favour endourological management over shock wave lithotripsy (SWL) in the management of moderate-sized (10–20 mm) renal stones. International guidelines support all available modalities for the treatment of these stones. The aim of this study was to evaluate the efficacy of SWL in the treatment of 10- to 20-mm renal stones. From January 2013 to October 2014, all patients with a renal stone measuring between 10 and 20 mm in maximum diameter on CT scan that were eligible for lithotripsy were included. 130 consecutive patients were evaluated. Demographics, location of stone within the kidney, number of SWL sessions and treatment outcomes were analysed. Treatment success was classified into complete stone clearance and the presence of clinically insignificant residual fragments <4 mm (CIRF). 119 patients (92 %) completed treatment and radiological follow-up. Eleven patients were excluded due to incomplete follow-up data. The mean age was 56.8 (23–88). Male to female ratio was 1.9:1 (78:41) and the mean BMI was 28.4 (17.9–58). The mean stone size was 12.8 mm (10–14 mm: n = 87; 15–20 mm: n = 32). The mean number of treatments was 2.14 and 2.82 for stones 10–14 and 15–20 mm, respectively. Overall treatment success was 66.4 % (combined complete stone clearance and CIRFs). Subdivided by stone size <15 mm and ≥15 mm, the success rate was 70.4 and 53.1 %, respectively. The treatment success by stone location was 65, 64 and 70 % for upper, middle and lower pole stones, respectively and 67 % for PUJ stones. For those who failed SWL treatment, the majority 50 % (n = 20) were managed expectantly, 42.5 % (n = 17) required URS, and 7.5 % (n = 3) required PNL. This study suggests that SWL has an efficacy for treating larger renal stones (10–20 mm) that is equivalent to success rates for smaller stones in other series. As a low-risk and non-invasive procedure SWL should be considered a first-line treatment for these stones.