UTAS may increase urolithiasis-related problems, and knowledge regarding the treatment and management of these patients is evidently lacking. Although the stone characteristics in patients with UTAS seem complicated, leading to worse surgical outcomes, this multicenter retrospective analysis demonstrated that mini-ECIRS is a highly feasible and safe surgical option even for patients with UTAS without compromising treatment outcomes. To our knowledge, the present study is the first to investigate the utility and feasibility of mini-ECIRS in patients with UTAS.
Urinary stasis resulting from anatomical abnormalities promotes urinary stone formation by causing a delayed washout of crystal aggregates and urinary tract infections [4]. In this study, the UTAS group showed a higher stone number and more frequent infectious stones than the non-UTAS group, with no difference in stone burden. Among the ten cases of ileal conduit, the most common type in this study's UTAS, seven cases included infectious stones as components. Patients with UTAS exhibited a higher prevalence of preoperative pyuria and UTI, suggesting an increased number of cases requiring preoperative stenting and nephrostomy for UTI management.
Congenital anomalies of the kidney and urinary tract have been reported to permit the effective use of URS [8–10] and PCNL [11–13], achieving a satisfactory SFR with low-risk complications. In terms of reports on stone surgeries in patients with a history of urinary tract surgery, only one retrospective study has compared PNL and URS in patients with an ileal conduit [14]. This study indicated that the SFR on the mini-ECIRS was equivalent between the non-UTAS (62.8%) and UTAS (62.7%) groups. UTAS did not prolong the surgical time of mini-ECIRS, although anatomical abnormalities may increase surgical difficulty. In the UTAS group, the higher proportion of preoperative stenting and nephrostomy may have simplified surgical techniques, potentially resulting in no significant difference in surgical time. The multivariable model also showed UTAS did not directly contribute to the SFR, and stone burden and the number of involved calyces were identified as risk factors for non-SF, as previously well reported [6, 7, 15].
The overall complication rate was not significantly different between the non-UTAS (29.6%) and UTAS (29.5%) groups. Fever/SIRS was the most frequently observed complication, followed by septic shock, organ injury, and renal vascular complications, and no significant difference was observed between the groups for each complication. UTAS was not a significant risk factor for perioperative complications, including infectious and bleeding-related events, and did not contribute to an increase in these complications. Thus, our study revealed that mini-ECIRS can be safely performed in patients with comparable complication rates comparable to those in patients without UTAS.
In this study, preoperative UTI, female sex, and number of calyces involved were identified as risk factors for perioperative complications of mini-ECIRS, as previously reported for ECIRS [15, 16] or mini-PCNL [17]. Additionally, preoperative nephrostomy reduces the complication risks. Preoperative nephrostomy is a well-known procedure that reduces the risk of severe infectious complications [18, 19] and bleeding [18] in PCNL. Preoperative nephrostomy facilitates drainage, suppresses intrapelvic pressure, and shortens the surgical procedure for ECIRS. In this cohort, compared with non-UTAS patients, those with UTAS had a higher implantation rate for preoperative nephrostomy. This may explain the finding that UTAS was not an independent predictor of perioperative complications in the present study, although patients with UTAS tended to have a preoperative urinary tract infection history. Therefore, proactive measures, such as preoperative nephrostomy, may be important in managing UTAS patients with UTI.
This study had several limitations. It is retrospective in nature, involves multiple centers, leading to variations in surgical approaches due to diverse operators, and may exhibit potential selection bias in cases of UTAS, where less invasive procedures, such as URS, could be preferred based on clinical judgment. The number of patients with UTAS was relatively small, which may have resulted in poor statistical power to obtain proper significance.