BACKGROUND: Primary and incisional ventral hernia trials collect unstandardized inconsistent data, limiting data interpretation and comparison. This study aimed to create two minimum data sets for primary and incisional ventral hernia interventional trials to standardize data collection and improve trial comparison. To support these data sets, standardized patient-reported outcome measures and trial methodology criteria were created. METHODS: To construct these data sets, nominal group technique methodology was employed, involving 15 internationally recognized abdominal wall surgeons and two patient representatives. Initially a maximum data set was created from previous systematic and panellist reviews. Thereafter, three stages of voting took place: stage 1, selection of the number of variables for data set inclusion; stage 2, selection of variables to be included; and stage 3, selection of variable definitions and detection methods. A steering committee interpreted and analysed the data. RESULTS: The maximum data set contained 245 variables. The three stages of voting commenced in October 2019 and had been completed by July 2020. The final primary ventral hernia data set included 32 variables, the incisional ventral hernia data set included 40 variables, the patient-reported outcome measures tool contained 25 questions, and 40 methodological criteria were chosen. The best known variable definitions were selected for accurate variable description. CT was selected as the optimal preoperative descriptor of hernia morphology. Standardized follow-up at 30 days, 1 year, and 5 years was selected. CONCLUSION: These minimum data sets, patient-reported outcome measures, and methodological criteria have allowed creation of a manual for investigators aiming to undertake primary ventral hernia or incisional ventral hernia interventional trials. Adopting these data sets will improve trial methods and comparisons.

3rd Department of Surgery Motol University Hospital 1st and 2nd Medical Faculty of Charles University Prague Czech Republic

Abdominal Wall Unit General Surgery University College London Hospital London UK

Centre for Medical Imaging University College London London UK

Department of Abdominal Surgery University Hospitals of the Katholieke Universiteit Leuven Leuven Belgium

Department of Colorectal Surgery University Hospital of Wales Cardiff UK

Department of General and Hepatobiliary Surgery and Liver Transplantation University Hospital Ghent Ghent Belgium

Department of General and Upper Gastrointestinal Surgery North Devon District Hospital Barnstaple UK

Department of General Digestive and Endocrine Surgery Robert Debré University Hospital University of Reims Champagne Ardenne Reims France

Department of Surgery Amsterdam University Medical Centre Amsterdam the Netherlands

Department of Surgery Onze Lieve Vrouwe Gasthuis Hospital Amsterdam the Netherlands

Department of Surgery Royal Infirmary of Edinburgh Edinburgh UK

Department of Surgery Skåne University Hospital Malmö Malmö Sweden

General Surgery Digestive Disease Centre Bispebjerg Hospital University of Copenhagen Copenhagen Denmark

Intestinal Failure Unit Salford Royal NHS Foundation Trust Salford UK

Patient Representative Glasgow UK

Patient Representative Liverpool UK

Unit of Innovation in Minimally Invasive Surgery Department of Surgery University Hospital Virgen del Rocio University of Seville Seville Spain

References provided by Crossref.org

Midline incisional hernia guidelines: the European Hernia Society