POIROT trial: post-operative imaging after urethroplasty with peri-catheter retrograde urethrography or trial of voiding with voiding cysto-urethrography

Purpose This study directly compares peri-catheter retrograde urethrography (pcRUG) and voiding cysto-urethrography (VCUG) as early postoperative imaging after urethroplasty and aims to assess whether pcRUG is superior at avoiding catheter reinsertion. Methods This is a single-center, prospective, interventional study comparing pcRUG and VCUG after urethroplasty in a within-patient fashion. All participants were first evaluated with pcRUG and subsequently with VCUG, unless pcRUG revealed significant contrast extravasation warranting further catheter stay. The primary end-point was to assess whether pcRUG is superior at avoiding catheter reinsertion compared with VCUG. Secondary end-points included the amount of significant contrast extravasations missed on pcRUG and the differences in radiation exposure. Results 80 patients were included in this study. Median (IQR) interval between surgery and first postoperative imaging was 16 (9–16) days. In 14/80 (18%) patients, the pcRUG showed significant contrast extravasation and catheter reinsertion was avoided, while this percentage is 0 by default for VCUG ( p < 0.001). In the other 66/80 (82%) patients, a VCUG was performed and 1/66 (1.5%) of these was considered as significant contrast extravasation. Notably, 9/66 (14%) of these patients could not void during the investigation. Median (IQR) dose of radiation exposure during pcRUG and VCUG was, respectively, 120 (84–161) mGy/cm 2 and 241 (169–334) mGy/cm 2 ( p < 0.001). Conclusions After urethroplasty, pcRUG is a valuable alternative for VCUG as early postoperative imaging. It has a comparable diagnostic yield, averts the risk of having to reinsert the catheter, avoids the problem of patients being unable to void during the examination and requires significantly less radiation.