Vol.:(0123456789) 1 3 World Journal of Urology https://doi.org/10.1007/s00345-019-02746-2 ORIGINAL ARTICLE Optimal non‑invasive treatment of 1–2.5 cm radiolucent renal stones: oral dissolution therapy, shock wave lithotripsy or combined treatment—a randomized controlled trial Mohammed A. Elbaset 1  · Abdelwahab Hashem 1  · Ahmed Eraky 2  · Mohammed A. Badawy 3  · Ahmed El‑Assmy 1  · Khaled Z. Sheir 1  · Ahmed A. Shokeir 1 Received: 23 October 2018 / Accepted: 27 March 2019 © Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract Purpose To evaluate the efcacy of oral dissolution therapy (ODT), shock wave lithotripsy (SWL), and combined SWL and ODT for medium-sized radiolucent renal stone (RLS). Methods A randomized controlled trial for patients with medium-sized RLS, 1–2.5 cm, ≤ 500 Hounsfeld unit (HU). The ODT patients were counseled for oral potassiumsodium-hydrogen citrate (Uralyt-U ® ). The 2nd group underwent SWL and the last group had combined SWL and ODT. The primary outcome, stone-free rate (SFR) at 3 months, was assessed by non- contrast computed tomography (NCCT). We defned complete response (success) if no residual fragment were detected by NCCT; partial response (failure) if there was a decrease in stone size, but presence of residual stones; no response if there was no change or increase in stone size (failure). Results 150 patients completed follow-up. The SFR at 1st month and 3rd month were, respectively; 16% and 50% in the ODT group, 10% and 46% in the SWL group, and 35% and 72% patients in combined group with (p = 0.03 and 0.003, respectively. The overall SFR for all groups was 66%. Combined treatment and initial response in frst month follow-up were independent factors predicting SFR. In addition, combined treatment signifcantly decreased the overall stone volume (p = 0.03) and the need for additional stone management procedures after 3 months (p = 0.01). Conclusion Combined ODT and SWL treatment constitutes the most rapid and efective therapeutic approach for medium- sized RLS, decreasing overall stone volume as well as the number of SWL sessions needed in comparison to SWL therapy, alone. Keywords Urolithiasis · Radiolucent stones · Shock wave lithotripsy (SWL) · Dissolution therapy Introduction The lifetime risk of urinary stone disease is about 10–15% in the developed world and 20–25% in the middle-east with a recurrence rate as high as 50% at 5 years, 50–60% at 10, and up to 75% at 20 years without preventative treatment [1]. Uric acid radiolucent renal stones (RLS) represent up to 10% of urinary stones. In their pure form they can be distinguished by single-energy multidetector CT with stone density values that are between 200 and 450 Hounsfeld units (HU) [2]. Low urine volume, hyperuricosuria and acidic urinary environment are the principal pathophysiologic mechanisms responsible for uric acid stone formation. For prevention of their recurrence, guidelines recommend achieving a pH > 6.0 by potassium citrate therapy [3]. Oral alkalinization therapy Khaled Z. Sheir and Ahmed A. Shokeir are equal last author. * Abdelwahab Hashem abdelwahab_hashem@yahoo.com; abdelwahab.hashem@gmail.com 1 Urology Department, Urology and Nephrology Center, Mansoura University, Mansoura, Egypt 2 Urology Department, Mediclin Muritz Hospital, Waren, Germany 3 Radiology Department, Urology and Nephrology Center, Mansoura University, Mansoura, Egypt