Randomization and blinding
Randomization was performed in permuted blocks using sealed opaque envelopes prepared by the IMBI. Intraoperatively, randomization took place after successful source control and abdominal lavage and before the closing of the abdominal wall.The outcome assessors of the CONTINT trial were blinded to the patients’ trial intervention. The primary endpoint had to be assessed by a board-certified surgeon familiar with the examination of the abdominal wall and at least six months training in ultrasound.