Surgical techniques and randomization
BLIND
Patients were electronically randomized on the day before surgery. They were allocated to the treatment group (with drainage) or the control group (without drainage). A clinical nurse performed the randomization through a web-based service (This study was not blinded due to technical limitations. Indeed, it would have been difficult to blind the operators placing a drain and to blind the patients due to the presence of dressings and drain bottles.The surgical technique was standardized in both groups. All patients underwent an open repair according to the Rives-Stoppa procedure [