1. CONGENITAL DIAPHRAGMATIC HERNIA
Dr. Manish Kumar Gupta
Assistant Professor
Department of Paediatric Surgery
AIIMS, Rishikesh

2. Surgical intervention Outcomes
Introduction
Epidemiology
Associated anomalies
Embryology
Pathology
Diagnosis
Pre-natal diagnosis
Clinical presentation
Prenatal care
Pre-operative care
Surgical intervention
Outcomes

3. Introduction
Congenital diaphragmatic hernia (CDH) is a common malformation characterized by a defect in the posterolateral diaphragm, the foramen of Bochdalek, through which the abdominal viscera migrate into the chest during fetal life.

4. Epidemiology Incidence- 1 in 2000 to 5000 per live birth.
One third of neonates with CDH are stillborn.
So, the exact prevalence of the disease is underestimated.
When still births are counted with live birth, the incidence is more common in females.
Infants with isolated CDH are typically premature, macrosomic male.

5. One third are associated with a major congenital anomaly.
Approximately 80% are left sided.
Bilateral defects are rare and are associated with other major anomalies.
Although the exact etiology remains unknown, mothers that are thin or underweight may have an increased risk of bearing an infant with CDH.

6. CDH may be due to the exposure of genetically predisposed or susceptible individuals to environmental factors.
Exposure to a number of pharmacologic agents and environmental hazards has been implicated in its development.
These include insecticides and drugs, such as phenmetrazine, thalidomide, quinine, cadmium, lead, and nitrofen.
Retinoid-regulated target genes may be responsible for CDH development. (Vitamin A deficiency is seen in patients of CDH)

7. Associated anomalies Approximately 50% of CDH are isolated defects.
Others are associated with anomalies of the cardiovascular (27.5%), urogenital (17.7%), musculoskeletal (15.7%), and central nervous (9.8%) systems (CNS).
Anomalies as a consequence of diaphragmatic defect:
lung hypoplasia, intestinal malrotation, some cardiac malformations, and patent ductus arteriosus (PDA) are considered to be consequences of the diaphragmatic defect.
Non-CDH-related defects are estimated to occur in 40–60% of cases and can involve the cardiovascular, CNS, gastrointestinal, and genitourinary systems.

8. Development of diaphragm
The fully developed diaphragm is derived from four distinct components:
the anterior central tendon forms from the septum transversum
the dorsolateral portions form from the pleuroperitoneal membranes
the dorsal crura evolve from the esophageal mesentery
the muscular portion of the diaphragm develops from the thoracic intercostal muscle groups.
The pleuroperitoneal folds grow ventrally and fuse with the septum transversum and dorsal mesentery of the esophagus during gestational week 6.
Complete closure of the canal takes place during week 8 of gestation.
Anatomically, the right side closes before the left.
Neuro-muscularization of the diaphragm is the last in the development and matures the diaphragm.

9. Development of Diaphragm
The fully developed diaphragm is derived from four distinct components: (1) the anterior central tendon forms from the septum transversum, (2) the dorsolateral portions form from the pleuroperitoneal membranes, (3) the dorsal crura evolve from the esophageal mesentery, and (4) the muscular portion of the diaphragm develops from the thoracic intercostal muscle groups. The pleuroperitoneal folds grow ventrally and fuse with the septum transversum and dorsal mesentery of the esophagus during gestational week 6. Complete closure of the canal takes place during week 8 of gestation. Anatomically, the right side closes before the left. Neuro-muscularization of the diaphragm is the last in the development and matures the diaphragm.

10. Pathology of CDH Failure of closure of pleuro-peritoneal canal
Most common area is a postero-lateral defect ( Bochdalek )
Left side more common
Herniated contents
Left- left lobe of liver, spleen and bowel
Right- Liver and other viscera.
If closure of the pleuroperitoneal canal has not occurred by gestational weeks 9 and 10, the abdominal viscera herniate through the lumbocostal trigone into the ipsilateral thoracic cavity. Most common site is the postero-lateral defect. Left side is more common than right side. Herniated contents often include the left lobe of the liver, the spleen, and almost the entire gastrointestinal tract.

11. Lung development in CDH
Both the lungs are affected-Lung hypoplasia.
Ipsilateral > Contralateral
No. of bronchial branches – greatly reduced
Alveolar development severely affected
Increased muscle mass in the conducting airways
Unilateral visceral herniation affects both ipsilateral and contralateral lung development with hypoplasia more severe on the ipsilateral side. The number of bronchial branches in the affected lung is greatly reduced. This finding is noted in both ipsilateral and contralateral lungs. Alveolar development is severely affected, and it has been reported that few normal alveoli exist in the lungs at term. There is greater muscle mass in the conducting airways.

12. Pulmonary vasculature in CDH
Both the lungs are affected.
Reduction in the total no. of branches
Significant adventitial and medial wall thickening
No significant changes in pulmonary venous structure
Increased susceptibility to PPH
hypoxia, acidosis, hypothermia, stress
The pulmonary vascular bed is distinctly abnormal in lungs from patients with CDH. There is reduction in the total number of arterial branches in both the ipsilateral and the contralateral pulmonary parenchyma. Structurally, there is significant adventitial and medial wall thickening in pulmonary arteries with abnormal muscularization of the small arterioles which leads to increased susceptibility to the development of fixed and intractable pulmonary hypertension. No significant changes in pulmonary venous structure is seen. Postnatally, additional exacerbations of pulmonary vascular resistance may be induced by hypoxia, acidosis, hypothermia, and stress.

13. Problems: in CDH Respiratory distress Hypoxia Hypercarbia
So, in a case of CDH, the respiratory distress causes hypoxia, metabolic acidosis and hypercabia and it further, increases the pulmonary vascular resistance leading to further respiratory distress and thus forming a viscious cycle.
Hypercarbia
Metabolic acidosis

14. Diagnosis: Prenatal Diagnosis
Prenatal USG:
Mean gestational age at discovery is 24weeks.
Presence of polyhydramnios (80% cases of CDH)- due to kinking of the gastro- esophageal junction by translocation of the stomach into the thorax with resultant foregut obstruction.
Presence of stomach in the fetal thorax at the same cross-sectional level of heart.
Three-dimensional estimation of the fetal lung volume: important prognostic indicator.
Lung-to-head ratio has been the most widely used prognostic indicator.
Fetal MRI

15. Fetal ultrasound image at the level of the four chamber heart (dotted arrow). Gastric bubble (solid arrow) at the level of the four-chamber heart suggests CDH.

16. Clinical presentation
Newborns with CDH typically present with respiratory distress.
Immediate respiratory distress with associated low Apgar scores to an initial stable period and a delay in respiratory distress for 24 to 48 hours.
Initial signs associated with respiratory distress include tachypnea, chest wall retractions, grunting, cyanosis, and pallor.

17. On physical examination:
scaphoid abdomen and an increased chest diameter.
The point of maximal cardiac impulse is often displaced, suggesting mediastinal shift.
Bowel sounds may be auscultated within the chest cavity with a decrease in breath sounds bilaterally.
Chest excursion may be reduced, suggesting a lower tidal volume.

18. The diagnosis of CDH is typically confirmed by a chest radiograph demonstrating intestinal loops within the thorax.
The abdominal cavity may have minimal to no gas.

19. Here we can see that the left dome of diaphragm was elevated and presence of abdominal viscera in the left hemithorax with mediastinal shift.

20. Right-sided CDH.

21. Occasionally, CDH may be completely asymptomatic and is only discovered incidentally.
Older patients who present later in life have a much better prognosis due to milder or absent associated complications, such as pulmonary hypoplasia and hypertension.

22. Prenatal Care
Referral to tertiary care centres where respiratory distress of neonates can be managed.
Prenatal corticosteroids:
To enhance the lung development in the premature infants
Role in CDH is not determined.

23. Pre-operative care Resuscitation:
Cardio-respiratory system stabilisation
Endotracheal intubation
Nasogastric tube insertion
Ventilation by mask and Ambu bag is contraindicated to avoid distention of the stomach and intestines that may be in the thoracic cavity.
Arterial and venous access through umbilicus
Infant to be properly sedated
Ventilation at low pressures and high rate

24. Pharmacology: Drugs to reduce pulmonary hypertension: Surfactants:
calcium channel blockers, prostacyclin derivatives, endothelin receptor antagonists, and phosphodiesterase-5 inhibitors such as sildenafil
Surfactants:
There is deficiency of surfactants in CDH.
May improve respiratory function: doubtful overall benefit
Inhalational nitric oxide:
Potent vasodilator
May reduce pulmonary hypertension

25. Surgery Timing of surgery: Surgical steps:
CDH is a medical emergency not a surgical emergency.
Surgery once the baby is stabilised with minimal respiratory support and least pulmonary hypertension.
Surgical steps:
Ipsilateral abdominal incision
Defect is exposed.
Reduction of the abdominal viscera
Closure of the defect : Primary or grafts
Wound closure

28. Case -3: (CDH)
Once, the herniated contents were reduced, the diaphragmatic defect was identified.
Intra-operative pictures showing the diaphragmatic defect and margins of diaphragm

29. Case -3: CDH
The ipsilateral hypoplastic lung was visualised after some degree of positive pressure ventilation. The defect was closed by approximation of the edges of the hernia with non absorbable sutures.

30. Other surgical approaches
Thoracic approach
Minimal access surgery
Thoracoscopic approach
Laparoscopic approach

31. Post surgery, the baby is kept on mechanical ventilatory supports with abdominal decompression with the help of nasogastric tube, rectal washes, and urinary catheterisation.
Gradually, supports are weaned.

32. Outcome Survival rates at advanced centres are 60-90%.
CDH survivors are at significant risk for chronic neurologic, developmental, gastrointestinal, nutritional, pulmonary, musculoskeletal, and other disorders.
Late deaths have been reported in approximately 10% of initial survivors, mainly because of the consequences of persistent pulmonary hypertension.

33. Neurodevelopmental abnormalities.
Respiratory risk:
Pneumonias
Reactive airway disease
Cor pulmonale
Gastrointestinal:
Gastroesophageal reflux
Nutritional and growth related problems
Malrotation
Musculoskeletal:
Chest wall deformities and scoliosis
Neurodevelopmental abnormalities.
Problems in motor and cognitive skills.