[Trial sequential analysis in evaluation of clinical guidelines (midline incisional hernia model)]

To evaluate the methodology of Trial Sequential Analysis as a tool for developing and critically appraising of clinical guidelines on the model of midline ventral hernias.

Systematic searching for international guidelines on the management of ventral hernias was conducted in the PubMed, EMBASE, Scopus, Web of Science, CINAHL, and Cochrane Library databases up to May 01, 2023. Searching depth was 5 years. Quality of systematic reviews was assessed using a Critical Appraisal Sheet from the Oxford Center for Evidence-Based Medicine. TSA was performed using Copenhagen Trial Unit (Centre for Clinical Intervention Research, Denmark) software. We analyzed sensitivity of models using relative risk reduction rates.

We analyzed 3 international guidelines on the management of primary and incisional ventral hernias: the International Endohernia Society (IEHS, 2019), the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES, 2016), and the European Hernia Society (EHS, 2023). Systematic reviews in all guidelines had high quality. The IEHS (2019) and SAGES (2016) guidelines synthesized evidence without meta-analytical processing, whereas the EHS (2023) guideline incorporated meta-analysis. Our supplementary TSA calculations demonstrated that EHS (2023) guideline evidence base is sufficiently powered to identify diabetes mellitus and surgical site infection as key risk factors of incisional hernia following midline laparotomy. Alloplastic mesh appeared to be a preventive factor against hernia recurrence compared with suture repair. Nonetheless, optimal mesh placement technique remains inconclusive.

To ensure necessary evidence base for updated guidelines on midline ventral hernias, further protocol studies are needed, including international collaboration. An alternative option for achieving a larger sample size, but with lower evidence base, could be research of surgical registries.