Diaphragmatic hernia

Classification

• Bochdalek hernia (posterolateral)
  • More common
  • Congenital posterolateral defect, usually on the left
  • Through lumbocostal triangle (also known as 'Bochdalek's foramen') - space between muscle fibres originating from the 12th rib, and the lateral arcuate ligament
  • Main effect is respiratory (protrusion of abdominal organs into thorax leads to pulmonary hypoplasia)
• Morgagni hernia
  • Much less common
  • Anterior, central, retrosternal defect
  • Congenital defect of the midline diaphragm resulting in herniation into anterior mediastinum
  • Defect in development of septum transversum with consequent lack of fusion of the sternal and costal fibrotendinous elements of the diaphragm
  • Always has a sac
• Congenital or acquired
• Sac vs no sac (eventration)

Pathophysiology

• When congenitally present, can lead to pulmonary hypoplasia and then respiratory insufficiency and pulmonary hypertension - common with Bochdalek, not with Morgagni

Presentation

• Bochdalek
  • Presents immediately on birth
• Morgagni hernia
  • Can present in adults or children
  • Pain or constipation from intermittent partial colonic obstruction
  • Epigastric or substernal fullness
  • Viscus can incarcerate or strangulate

Management

• Congenital Bochdalek hernia
  • Delayed operative approach - deferred until cardiorespiratory stabilisation is achieved, which can take weeks
  • Reduction of herniated contents and closure of the diaphragmatic defect
  • Most infants go home off oxygen
• Congenital Morgagni hernia
  • Better outcomes due to absence of respiratory defects seen with Bochdalek hernias
  • Repair is indicated in all patients due to risk of strangulation
    • Emergency: upper midline laparotomy
    • Elective: generally laparoscopic repair
  • Resect sac then primary repair with non-absorbable horizontal mattress sutures. Diaphragm secured to the posterior part of the sternum and to the posterior rectus sheath.
    • Mesh only if needed due to large defects and weak tissue - some sort of synthetic mesh, will need to be coated
  • Recurrence is rare and results are excellent

For operative technique, see topic under 'trauma'