Diaphragmatic hernia (foramen of Bochdalek)

A foramen of Bochdalek hernia is a congenital disorder of the diaphragm that frequently presents as a neonatal emergency.(1)

The hernia tends to be large and may present as respiratory distress shortly after birth. It often strangulates. The prevalence of Bochdalek hernia is about 1/2200 births.

On chest radiography the hernia is seen as a round or oval mass or air-filled viscus in the posterior mediastinum, more commonly on the left hand side. It may be confirmed by barium studies of the gut and an excretory urogram.

Thin-section CT with multiplanar reformats has now become the industry standard for diagnosis due to increased sensitivity and ability to evaluate associated congenital anomalies. On CT of the chest, one can more accurately assess for focal defects in the diaphragm. CT is reported to have sensitivities of 78% for left-sided hernias and 50% for right-sided hernias. (2)

Antenatally, expected management and surveillance for complications is the standard of care. Sometimes, in severe herniation, fetoscopic endoluminal tracheal occlusion (FETO) therapy can be considered. This procedure temporarily blocks the trachea, and preliminary research suggests it improves lung development. (3)

Postnatally, management of hypoplastic lung tissue and maldevelopment takes precedence; this includes gentle ventilation, high-frequency oscillatory ventilation (HFOV), and extracorporeal membrane oxygenation (ECMO) therapies. (3)

In adults, these hernias can go undetected and become surgical emergencies if abdominal organs become strangulated, resulting in conditions like intestinal obstruction or gastric volvulus. Surgical repair is the only effective treatment for Bochdalek hernia in adults, preventing long-term complications and improving quality of life. Experienced surgeons often prefer a laparoscopic approach due to its minimal invasiveness and quicker recovery time. (4)

Overall survival rates vary across the literature, with most population-based studies suggesting an overall mortality rate between 42% and 68%, although some single-institution studies suggest a survival rate of upwards of 90%. (5)

Reference:

1. Kardon G et al. Congenital diaphragmatic hernias: from genes to mechanisms to therapies. Dis Model Mech. 2017 Aug 01;10(8):955-970
2. Alamo L, Gudinchet F, Meuli R. Imaging findings in fetal diaphragmatic abnormalities. Pediatr Radiol. 2015 Dec;45(13):1887-900
3. Leeuwen L, Fitzgerald DA. Congenital diaphragmatic hernia. J Paediatr Child Health. 2014 Sep;50(9):667-73.
4. Katsaros I et al. Bochdalek hernias in the adult population: a systematic review of the literature. ANZ J Surg. 2022 Sep;92(9):2037-2042.
5. Wigen RB, Duan W, Moraes TJ, Chiu PPL. Predictors of Long-Term Pulmonary Morbidity in Children with Congenital Diaphragmatic Hernia. Eur J Pediatr Surg. 2019 Feb;29(1):120-124