Rediscovering the Infracardiac Bursa: Important Surgical Landmark and Key to Understanding Complex Hiatus Hernia?

Background: The infracardiac bursa (ICB) is a variably sized mesothelial cavity in the lower posterior mediastinum on the right side of the esophago-gastric junction (EGJ), historically described as a remnant of the omental bursa. Despite recent studies suggesting its common presence, its clinical significance might be underestimated, leading to unexpected encounters and misidentification during surgery. A persistent omental bursa-ICB connection can exist, with unknown precise prevalence. This paper highlights the ICB’s potential clinical relevance for esophageal surgeons, focusing on its importance as a surgical landmark and potential role in a specific, underreported type of atypical hiatal hernia (HH). Methods: To assess the prevalence of ICB in adults, a retrospective video analysis of 100 consecutive primary HH repairs was performed, evaluating for atypical posterior defects. Furthermore, two atypical cases with persistent omental bursa-ICB connection are discussed: one with paraesophageal omental herniation, the other incidentally found during esophagectomy. Results: The video analysis revealed potential persistent omental bursa-ICB communications in 3% of patients. Inter-observer concordance for atypical posterior defects was high, suggesting this is a distinct, underdiagnosed clinical entity. In both clinical cases, classic Type I-IV HH features were absent and intraoperative findings solely revealed a large, non-reducible hernia sac originating from the omental bursa extending into the right paraesophageal mediastinum. We hypothesize these are congenital herniations due to a persistent omental bursa-ICB communication. Conclusions: The ICB and specifically, its potential connection to the omental bursa, is a relevant anatomical peculiarity. Increased recognition of this entity and associated pathologies around the EGJ may improve diagnosis and management of HH.