LAUSR

Purpose The effect of combining miniaturization with endoscopic combined intrarenal surgery (ECIRS) is unclear. Thus, we compared the treatment outcomes between minimally invasive ECIRS (mini-ECIRS) using 16.5 Fr percutaneous access sheath and standard ECIRS using 24 Fr access sheath for renal stones Materials and methods We retrospectively analyzed consecutive patients who underwent single session mini or standard-ECIRS in the modified Valdivia position for renal stones between April 2009 and May 2016. To adjust for patient characteristics, 77 pairs were matched using preoperative parameters including age, sex, history of febrile urinary tract infection (UTI), stone surface area, number of involved calyces, and staghorn calculi. Results The stone free rate (SFR) was similar between mini and standard ECIRS according to non-contrast computed tomography (61.1% vs. 52.0%, p  = 0.388). The rate of perioperative complications exceeding grade 2 based on the Clavien-Dindo classification was similar in both groups (19.5% vs. 26.0%, p  = 0.442). Severe complications exceeding grade 3 were also similar in both groups (2.6% vs. 3.9%, p  > 0.99). Two cases of septic shock were noted in each group. Although there was no difference regarding bleeding-related complications (2.6% vs. 6.5%, p  = 0.442), pseudoaneurysm or blood transfusion was not observed in the mini-ECIRS group. Pain visual analog scale values in the perioperative period were lower in the mini-ECIRS group (1.34 ± 1.08 vs. 1.69 ± 1.23, p  = 0.062). Conclusions This study demonstrated that, compared to standard ECIRS, mini-ECIRS maintained SFR without increasing perioperative complications, tended to reduce postoperative pain and had a potential to reduce bleeding-related complications. This report suggests the advantages of ECIRS miniaturization for renal stones.