Who will be blinded {17a}
Blinding will be performed according to the evidence-based guidelines published by Probst et al. [Patients are blinded as they are under general anaesthesia during the trial intervention. Neither the discharge letter nor the operation report will contain any information regarding group allocation. This will be monitored by the clinical monitor.Surgeons performing the operation are unblinded to the trial intervention. To minimise performance bias, randomisation is performed after the closure of the posterior wall of the abdomen.For blinded outcome assessment, the person performing randomisation and the surgical team conducting the control/experimental intervention (“unblinded” study members) will be documented. All outcome assessments must be performed by blinded clinical assessors The trial statistician is blinded as she/he has no access to unblinded data during the study. Furthermore, the statistician will perform according to a pre-defined statistical analysis plan which will be finished prior to database closure.For primary endpoint evaluation, a clinical as well as radiological examination needs to be performed. Clinical outcome assessment must be performed by a surgeon. Blinding the radiologic examination can be achieved easily, as these physicians are not part of the prior trial interventions or the clinical trial centre. For clinical evaluation, the same prerequisites apply as outlined above, i.e. surgeons performing the clinical evaluation must be independent of the “unblinded” trial team.