Flexible ureteroscopy for lower calyceal stones in a horseshoe kidney – Is it the new treatment of choice?

Introduction: The efficacy of retrograde intrarenal surgery (RIRS) for the treatment of disorders in a horseshoe kidney has not been sufficiently studied so far. We report on our experience with this method for the treatment of lower-pole calculi in patients with a horse-shoe kidney. Patients and methods: The files of 9 patients who underwent RIRS for lower calyceal stones in horseshoe kidneys between April 2012 and December 2014 were retrospectively analyzed. The stone-free status, postoperative complications, operative time and duration of hospitalization were assessed. Results: In total, 12 renal units with lower calyceal stones were treated, as 3 patients had stones in both kidneys. In 8 renal units complete stone clearance could be achieved in one sitting (67.7%), while in 3 renal units 2 sittings were necessary in order to achieve stone clearance. One patient with a stone sized 18 mm still had residual stones after two sittings and, therefore, underwent percutaneous nephrolithotomy (PCNL) for stone clearance. No major complications (Clavien–Dindo grades III–V) were encountered. Conclusion: RIRS for the treatment of stone disease in horseshoe kidneys has been shown to be a relatively safe and effective procedure. However, due to the anatomical abnormality, a second look may be needed to render the patient completely stone-free