Retroperitoneal vs transperitoneal laparoscopic lithotripsy of 20-40 mm renal stones within horseshoe kidneys

BACKGROUND Horseshoe kidney (HK) with renal stones is challenging for urologists. Although both retroperitoneal and transperitoneal laparoscopic approaches have been reported in some case reports, the therapeutic outcome of retroperitoneal compared with transperitoneal laparoscopic lithotripsy is unknown. AIM To assess the efficacy of laparoscopic lithotripsy for renal stones in patients with HK. METHODS This was a retrospective study of 12 patients with HK and a limited number (n <= 3) of 20-40 mm renal stones treated with either retroperitoneal or transperitoneal laparoscopic lithotripsy (June 2012 to May 2019). The perioperative data of both groups were compared including operation time, estimated blood loss, postoperative fasting time, perioperative complications and stone-free rate (SFR). RESULTS No significant difference was observed for age, gender, preoperative symptoms, body mass index, preoperative infection, hydronephrosis degree, largest stone diameter, stone number and isthmus thickness. The mean postoperative fasting time of the patients in the retroperitoneal group and the transperitoneal group was 1.29 +/- 0.49 and 2.40 +/- 0.89 d, respectively (P = 0.019). There was no significant difference in operation time (194.29 +/- 102.48 min vs 151.40 +/- 39.54 min, P = 0.399), estimated blood loss (48.57 +/- 31.85 mL vs 72.00 +/- 41.47 mL, P = 0.292) and length of hospital stay (12.14 +/- 2.61 d vs 12.40 +/- 3.21 d, P = 0.881) between the retroperitoneal and transperitoneal groups. All patients in both groups had a complete SFR and postoperative renal function was within the normal range. The change in estimated glomerular filtration rate (eGFR) from the preoperative stage to postoperative day 1 in the retroperitoneal group and the transperitoneal group was -3.86 +/- 0.69 and -2.20 +/- 2.17 mL/(min center dot 1.73 m(2)), respectively (P = 0.176). From the preoperative stage to the 3-mo follow-up, the absolute change in eGFR values for patients in the retroperitoneal group and the transperitoneal group was -3.29 +/- 1.11 and -2.40 +/- 2.07 mL/(min center dot 1.73 m(2)), respectively (P = 0.581). CONCLUSION Both retroperitoneal and transperitoneal laparoscopic lithotripsy seem to be safe and effective for HK patients with a limited number of 20-40 mm renal stones.