Prevalence of incidental Bochdalek's hernia in a large adult population.

OBJECTIVE: The purpose of this study was to determine the prevalence and characteristics of adult Bochdalek's hernia in a large patient population. MATERIALS AND METHODS: We retrospectively reviewed all abdominal CT scans obtained at our hospital in 1998. Patients in our study were identified through a keyword search of our database for "Bochdalek," "hernia," and "diaphragm." The individual patient studies identified were reviewed in a soft-copy format. We noted the location and side of the body on which the diaphragmatic hernia arose and the contents of the sac. We also performed a chart review for each patient included in the study, noting the patient's sex, age, and symptoms. RESULTS: Incidental Bochdalek's hernia was diagnosed in 22 patients (17 women, five men), which represents an incidence of 0.17% based on 13,138 abdominal CT reports we reviewed. The mean age of the patients was 66.6 years. None of the patients were symptomatic. Sixty-eight percent of the hernias were on the right side of the body, 18% were on the left side, and 14% were bilateral. Seventy-three percent contained only fat or omentum, whereas 27% had solid or enteric organ involvement including the spleen, small intestine, or large intestine. CONCLUSION: Bochdalek's hernia is not rare, and the incidence of Bochdalek's hernias that contain enteric tract is higher than previously reported. This incidence likely represents a conservative estimate because some Bochdalek's hernias may have been overlooked or unreported.