First-in-human safety and feasibility study of an acellular collagen mesh for augmentation urethroplasty: an IDEAL stage 1 study

Buccal mucosa graft (BMG) urethroplasty is the gold standard for substitution urethral reconstruction but is associated with donor-site morbidity. We conducted a first-in-human prospective feasibility study to evaluate the safety and functional outcomes of an off-the-shelf acellular collagen mesh designed as an absorbable alternative for augmentation urethroplasty. This is a single-arm IDEAL stage 1 study conducted at a tertiary centre with ethics approval and ClinicalTrials.gov registration (NCT05463991) on 27th July 2022. Five adult men with anterior urethral strictures ≤ 3 cm on urethrogram underwent dorsal or ventral onlay augmentation urethroplasty using a sterile, GMP-manufactured bovine collagen mesh. The primary endpoint was device safety, defined as device-related intra- or postoperative adverse events. Secondary outcomes included International Prostate Symptom Score (IPSS), quality of life (QoL), peak urinary flow rate (Qmax), and need for reintervention over 24 months. All procedures were completed without intraoperative complications. No device-related adverse events (infection, extrusion, erosion, or fistula) were observed. Three of five patients required interval urethral dilatation within 12 months, whereas no patient required redo urethroplasty. At 24 months, median IPSS improved from 24.5 preoperatively to 1, QoL from 4 to 2, and Qmax from 11.1 mL/s to 19.7 mL/s. These functional outcomes reflect the final clinical status after all postoperative management, including secondary urethral dilatation where required. Limitations include the small sample size, single-centre design, and absence of routine endoscopic assessment. This first-in-human series demonstrates 2-year safety and technical feasibility of an acellular collagen mesh for substitution urethroplasty. Functional voiding outcomes were restored without need for redo urethroplasty. Larger prospective studies with structured objective follow-up are required before clinical adoption.