Collagen implant versus gluteus maximus flap for perineal closure after extended abdominoperineal excision: NEAPE randomized clinical trial

BACKGROUND: Optimal reconstruction of the perineal defect after extended abdominoperineal excision remains uncertain, and randomized comparisons between biological mesh and myocutaneous flaps are lacking. This trial assessed whether an acellular porcine collagen implant (APCI) is non-inferior to a gluteus maximus myocutaneous flap (GMF) for pelvic floor reconstruction. METHODS: NEAPE was a multicentre, randomized, non-inferiority trial conducted in eight Nordic referral centres. Adults undergoing extended abdominoperineal excision for rectal cancer were randomized to reconstruction with an APCI or unilateral GMF. The primary outcome was the proportion of patients underperforming in the timed-stands test at 6 months, defined relative to age- and sex-matched reference values. The non-inferiority margin was -10%. RESULTS: Eighty-three patients were included in the modified intention-to-treat population (mean(standard deviation) age 68(10) years; 31% female). At 6 months, 71% of patients (25 of 35) in the implant group and 60% of patients (20 of 33) in the flap group underperformed. The risk difference was -11% (one-sided 95% confidence interval -30% to ∞), and non-inferiority was not demonstrated. CONCLUSION: The APCI did not demonstrate non-inferiority compared with the GMF. The direction of the effect favoured the flap, with results compatible with worse functional outcomes in the implant group. REGISTRATION NUMBER: ClinicalTrials.gov NCT01347697.