Ureter-ileum-interposition: Combined experience from two high-volume centres.

The current study aimed to evaluate short- and long-term complication rates and functional outcomes in a substantial cohort of patients undergoing ileal ureter interposition at two high-volume medical centres. Materials and methods: A retrospective single-arm analysis was conducted on patients who underwent ureter reconstruction using ileum between 2003 and 2022 at the University Clinic of Cologne and the National Cancer Institute of Ukraine. Data on aetiology, surgical techniques, pre- and postoperative kidney function changes, readmission rates and complication management were collected. Postoperative complications were classified according to Clavien-Dindo, and estimated glomerular filtration rate (eGFR) was calculated using the CKD-EPI formula. Results: Results revealed 107 cases with consistent data. Within 90 days post-surgery, 53% experienced complications, mainly graded as I-II. Grade III complications were seen in 13%, with two cases of grade IV complications leading to extended hospitalisation and patient death. The 90-day mortality rate was 1.8%. Over a mean follow-up of 52 months, clinically significant vesico-renal refluxes occurred in 28%, with only 5.4% leading to persistent urinary tract infection. Antireflux techniques appeared to reduce urine upflow incidence compared with conventional interposition. Anastomosis stricture occurred in 15% of patients, with 63% requiring permanent re-stenting and 37% needing re-anastomosis. Metabolic acidosis was clinically significant in 7.5% of cases. A slight improvement in renal function was observed during the first year post-surgery (average postoperative eGFR = 76 ± 22 ml/min; Mann-Witney Conclusion: Ileal ureter interposition demonstrated a favourable safety profile and functional outcomes. This surgical intervention provides an effective tension-free bypass, irrespective of healthy ureter length.