Congenital Posterolateral Diaphragmatic Hernia and Other Less Common Hernias of the Diaphrag

m in Infants and Children

A. CONGENITAL POSTEROLATERAL

DIAPHRAGMATIC HERNIAS• The diagnosis of a congenital diaphragmatic

hernia can be made in utero.

• Infants and older children who are found to have a congenital diaphragmatic hernia are not as severely affected as the neonate and should have 100% predicted survival.

Embryology

• The Bochdalec hernia is a classic posterolateral defect of diaphragm caused by failure of the pleuroperitoneal canal to close at 8 weeks’ gestation.

• The defect occurs on the left side 80% of the time and is occasionally bilateral.

• The hole can be 1-2 cm in size to total absence of hemidiaphragm.

• Fig 50-1

Embryology

• When the intestine return to the abdomen from the yolk sac, the abdominal organ will herniate to the chest at 10 weeks’ gestation

• The mediastinum will be pushed into contralateral side and both lungs will be hypoplasia.

Embryology

• 72% of posterolateral diaphragmatic hernia fetuses have extradiaphragmaic abnormalities, such as congenital heart disease, neural tube defect, genitourinary, skeletal, craniofacial anomaly, abdominal wall defect…etc.

Embryology

• Prognostic factors based on prenatal ultrasound is problematic.

• Prenatal diagnosis was ever considered a poor prognostic factor, but the significance decreased due to increased numbers of ultrasound.

• Observation of the liver in the chest is a poor prognostic factor.

Embryology

• Fetal abdominal circumference is less than fifth percentile is a poor prognostic factor.

• Metkus et al reported that the size of contralateral lung measured as a ratio of lung area to head circumference was the only absolute predictor of survival.

Presentation

• It may cause respiratory distress, feeding intolerance.

• Some patients have no symptoms.

• The diagnosis is suspected if the abdomen is scaphoid or heart sound can be heard in the right chest.

• Chest radiography can reveal air-filled loops of intestines or an NG tube.

• table 50-1

• Fig 50-2, -3

Presentation

• Any baby with respiratory distress at birth who is suspected to have a Bochdalec hernia must be intubated and ventilated. Mask bagging can increase abdominal distention and should be avoided.

• Mechanical ventilation with 100% FiO2 and low air pressure(<25 cm H2O with 5 cm of PEEP) should be used.

Presentation

• ECMO, dopamine (low dose), dobutamine, 5% albumin( 10-15 ml, IV bolus, for systemic hypotension) may be necessary.

• If a Bochdalec hernia is found in an older infant or a child incidentally, the hernia should be repaired at the time.

Management• NO therapy(to control pulmonary hypertens

ion) and partial liquid (perfluorocarbon) ventilation may be used.

• Hyperventilation and alkalosis were ever used to control pulmonary hypertension and persistent fetal circulation, but they are avoided to decrease ventilator-induced lung injury now.

Management

• If these are not useful, the ECMO is indicated.

• Table 50-2

Operative Correction

• A newborn must be stabilized at least 72 hours before operation.

• If vital signs deteriorate, a contralateral pneumothorax is suspected and a 10F chest tube must be placed.

• The correction is done through a paramedian incision.

Operative Correction

• Fig 50-5

Operative Correction

• Extralobar pulmonary sequestration is removed.

• A small defect is repaired with permanent suture and Teflon pladgets.

• A large defect is repaired with polytetrafluoroethylene membrane.

Operative Correction

• If a hemidiaphragm is absent completely, then a polytetrafluoroethylene membrane must be sutured on the ribs anteriorly and posterolaterally. The median portion of the membrane is sutured to the contralateral diaphragmatic leaf and the adventia overlying the esophagus and the aorta.

Operative Correction

• The use of chest tube is controversial. Suggestions include one chest tube, no chest tube, bilateral chest tubes, under water seal, and tube exposure to the atmosphere.

• Associated abdominal anomalies must be corrected during the operation.

Extracorporeal Menbrane Oxygenation(ECMO)

• Standard criteria have not established, but in generally include AaDO2< 600 for 12 hours; oxygen index>40; acute deterioration(pH <7.15 or PaO2<55mmHg) for 2 hours; failure of conventional management; and progressive barotrauma.

Extracorporeal Menbrane Oxygenation(ECMO)

• Contraindications include preexisting intraventricular hemorrhage; weight<2000 g; and congenital or neurologic abnormalities incompatible with a normal life.

Factors in Survival

• ABG pH< 7.0 with a PCO2>100 is a poor predictor.

• Toulokian et al reported a scoring system based on radiographic findings to predict the outcome. The findings include side of the hernia, location of the stomach, relative volume aerated lungs, and presence of a pneumothorax.

Factors in Survival

• Preoperative and postoperative AaDO2 >500 mmHg correlated little chance of survival.

• Wilson et al reported that best postductal PCO2 and the oxygenation-ventilation index (PCO2/mean airway pressure X respiratory rate X 100) were predictors of mortality. Infants who did not respond to conventional mechanical ventilation (best postductal PO2<100; best postductal PCO2>40, with ventilation index>1000) did not benefit from ECMO.

Future Prospects

• In utero correction of defect can allow sufficient growth of lung for survival in fetal lambs, but the technique did not improve outcome in humans.

• Antenatal tracheal occlusion (with balloon or clip) can reverse the lung hypoplasia in lambs, but the outcome of the technique remains to be seen in humans.

Long-Term Follow-Up

• Jeandot et al reported survivors after 1-2 years have a persistent reduced perfusion but improved ventilation.

• Vanomo et al reported no clinical impairment but some reduced exercise tolerance and minor ventilatory impairment.

• Anterior chest wall deformity, scoliosis, and G-E reflux were also noted by others.

Long-Term Follow-Up

• Recurrence may develop, especially in those babies who require patch repair.

•

B. MISCELLANOUS CONGENITAL

DIAPHRAGMATIC HERNIAS

B-1. Hernias through the Central Tendon of the Diaphragm

• If it occurs on the right side, a mushroom-like projection of liver can be seen. This projection will be misinterpreted a diaphragmatic tumor. Distinguishing can be done by creating a pneumoperitoneum. Air appears around the liver protrusion can be seen. Operation is not necessary.

B-1. Hernias through the Central Tendon of the Diaphragm

• If the hernia occurs in the left side, the stomach may herniate, a air-containing cyst can be seen on the top of the diaphragm. The hernia may associated with partial absence of pericardium, so cardiac symptoms may occur. The operation is done through an abdominal approach in infants and children but through thoracic approach in older children and adults.

B-2. Paraesophageal Hernia in Infants and Older Children

• It is congenital or acquired in infants and children.• The acquired variety is usually a complication of o

peration of G-E reflux.• UGI series reveals herniated stomach and other ab

dominal organs.• In some children, anemia may occur from gastritis

or esophagitis; vomiting from obstruction or incarceration.

B-2. Paraesophageal Hernia in Infants and Older Children

• Operation should be done in all cases and should include reduction of herniated organs; approximation of the crura. Anti-reflux procedure or gastropexy is also suggested to carry out.

B-3. Morgagni Hernia

• It is an anterior retrosternal diaphragmatic hernia.

B-3. Morgagni Hernia

• Anatomy

1. Lack of fusion or muscularization of

pleuroperitoneal membrane anteriorly can

lead a defect as known as Morgagni

foramen or space of Larrey .

2. The internal mammary artery may pass

through the space to rectus sheath and become

the superior epigastric artery.

B-3. Morgagni Hernia

• Anatomy

3. The peritoneum is intact so there

is usually a true hernia sac.

4. Left side is less involved because of

protection of the pericardium.

5. The ligamentum teres is the medial

border of the hernia.

Fig51-1

B-3. Morgagni Hernia

• INCIDENCE

1. It is uncommon.

2. Although it is congenital, it is found less

in a child than in a adult.

3. It is more in women and obese people.

4. Right side (90%), left side (2%), bilateral (8%).

Morgagni Hernia

• SYMPTOMS

1. 1/3 patients have no symptom.

2. Most frequent symptoms are cramping

pain, constipation from partial colonic

obstruction.

3. Gastric volvulus or small intestine

obstruction are less frequent.

Morgagni Hernia

• SYMPTOMS

4. Complete obstruction, incarceration, or

strangulation is rare.

5. Cardiorespiratory symptoms are less

common than GI symptoms.

6. Trauma, exercise and pregnancy can cause

the occurrence.

Morgagni Hernia

• Diagnosis 1. Chest radiograph reveals pericardiophrenic density that is solid or contain air. 2. The lateral view reveals retrosternal opacity. 3. Pericardial cyst, lobulated pneumothorax, fat pad, mediastinal tumor or bronchogenic carcinoma may mimic the hernia.

Fig51-2

Morgagni Hernia

• Diagnosis

4. Contrast study of colon and UGI can

confirm the diagnosis.

5. CT scan can reveal fat or a hollow organ.

6. MRI is not necessary.

Morgagni Hernia

• Surgical repair 1. All symptomatic adults should undergo repair. 2. Some reports showed asymptomatic adults should undergo repair to avoid incarceration and stranulation. 3. It is reasonable that patients with only omentum herniation or high operative risk do not need operation.

Fig.51-7

Morgagni Hernia

• Surgical repair

4. Repair can be done through paramedian,

subcostal or upper median incision

transabdominally.

5. A small defect can be closed primarily with

interrupted suture.

6. Prosthetic patches are necessary to close

larger defects.

Morgagni Hernia

• Surgical repair

7. It is not necessary to enter or to drain the

the pleural space.

8. Lapatroscopy and thoracoscopy are ever

used.

9. The mortality and morbidity are low.

10. Recurrence is rare.

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