A systematic review of hiatus hernia classifications

Summary Hiatus hernias (HH) are common and significantly impact symptoms and morbidity in Upper GI surgery, yet there is no consensus on classification. We previously identified various classification systems used in randomized trials, but these often lack clinical relevance. This inconsistency affects benchmarking, standardizing practice, and the ability to generate and answer research questions effectively. The aim of this review was to systematically identify and appraise what classification systems have been described and their association with treatment outcomes. We undertook a systematic review of the PubMed and EMBASE databases on the 17th January 2023. A total of 847 articles were identified and 304 were included, with a further 10 studies identified that tested a novel approach to classifying HH against surgical outcomes. The commonest method of classifying HH in the literature was Types I–IV used in 60% of studies. Other studies described endoscopic, manometric, anti-reflux, intraoperative, and postoperative classifications. Eighteen separate definitions were recorded for oversized HH; described as Massive, Giant, or Large. The quality of studies linking classifications to outcomes was limited, but some associations were noted based on anatomical and physiological factors. Types I–IV are the most common method of classifying HH in the literature. There was significant and overlap and discrepancy in the definitions used for Massive, Giant, and Large HH. Although evidence is limited, components such as intra-thoracic stomach or hiatal dimensions may improve HH classification and guide treatment, standardization, and research.