Outpatient services in Germany are less controlled by external quality assurance programs. Comprehensive outcome data for benchmarking or health-care decision-making are missing e.g. for day case surgery. A quality-of-life instrument specific to hernia repair with mesh has been recently proposed (Carolinas Comfort Scale, CCS) .This study evaluates the integration of CSS as part of a multicentre quality assurance scheme for day-case (outpatient) surgery.b.The Study Group on "Quality assurance in ambulatory hernia surgery" has developed and standardized Operation technique for 3D Implants. As a consequence, any deviation must be documented by the standard. The extension to other centers according to a standardized protocol took place (shadowing to learn the operational standards, training in documentation, Minimum quantity 30 interventions per year, etc.).