Background: Vessel-sparing anastomotic repair (vsAR) has been developed as a less traumatic alternative to transecting anastomotic repair (tAR) to treat isolated short bulbar urethral strictures. This vessel-sparing technique could result in improved functional outcomes without jeopardizing the excellent surgical outcome after (transecting) anastomotic repair. The purpose of this study is to directly compare vsAR and tAR for both surgical and functional outcomes.
Methods: This trial is a prospective, interventional, multi-center, single-blinded, 1:1 randomized, controlled, non-inferiority, phase II trial. Sample size calculation resulted in a required sample size of 100 patients (50 patients per arm). Trial participants will be randomized by an independent third party using a computer-based random sequence generator with permuted blocks of variable size. The primary objective of this trial is to show that vsAR is non-inferior to tAR in terms of failure-free survival after 24 months of follow-up, considering a non-inferiority limit of 10%. Failure is defined as the inability to pass a 16-Fr flexible cystoscope through the reconstructed area without damaging the urethral mucosa. Secondary end-points mainly include differences in postoperative complications and changes in functional outcome parameters, which will be assessed with validated questionnaires. All participants are scheduled for follow-up at 3, 12, and 24 months postoperatively.
Discussion: This trial will provide level Ib evidence about the differences in both surgical and functional outcome between vsAR and tAR, which may importantly scape the future of bulbar urethral reconstruction. Depending on the trial results, this phase II trial may generate a larger phase III trial with more statistical power and a lower alpha value.
Trial registration: This trial is registered at clinicaltrials.gov ( NCT03572348 ) and in the Belgian Clinical Trial Registry (B670201837335). The trial was registered prospectively. Registered on 28 June 2018.
Keywords: Anastomotic repair; End-to-end; Excision and primary anastomosis; Non-transecting; Randomized controlled trial; Transecting; Urethral stricture; Urethroplasty; Vessel-sparing.