Diaphragmatic hernia in children

diaphragmatic hernia in children pediatrics bochdaleck hernia morgagni hernia and surgery care

1. DIAPHRAGMATIC HERNIAS GROUP 20

2. Anatomy of Diaphragm In human anatomy, the thoracic diaphragm, or simply the diaphragm is a sheet of internal skeletal muscle that extends across the bottom of the thoracic cavity. The diaphragm separates the thoracic cavity, containing the heart and lungs, from the abdominal cavity and performs an important function in respiration: as the diaphragm contracts, the volume of the thoracic cavity increases and air is drawn into the lungs. It is a musculotendinous dome-shaped structure that demarcates pleural and peritoneal cavities.

3. Innervation: – Bilateral phrenic nerves (C3–C5) —Lower intercostal nerves • Arterial supply – Internal thoracic artery • Pericardiophrenic aa. • Musculophrenic aa. – Inferior phrenic arteries

4. Embryological development of Diaphragm

5. Diaphragmatic Hernia Diaphragmatic hernia is a defect or hole in the diaphragm that allows the abdominal contents to move into the chest cavity. Treatment is usually surgical. Types Congenital diaphragmatic hernia a. Morgagni’s hernia b. Bochdalek hernia

6. Congenital Diaphragmatic Hernia Congenital diaphragmatic hernia (CDH) is a birth defect of the diaphragm. The most common type of CDH is a Bochdalek hernia ; other types include Morgagni hernia , diaphragm eventration and central tendon defects of the diaphragm. Malformation of the diaphragm allows the abdominal organs to push into the chest cavity, hindering proper lung formation. Most CDH defects occur on the left side (80%); bilateral defects are extremely rare. Accurate determination of true survival rate is distorted by the fact that many infants with CDH are stillborn , and many reports tend to exclude infants with complex associated anomalies from survival calculations.

7. Types Bochdalek hernia The Bochdalek hernia, also known as a postero-lateral diaphragmatic hernia , is the most common manifestation of CDH. In this instance the diaphragm abnormality is characterized by a hole in the postero-lateral corner of the diaphragm which allows passage of the abdominal viscera into the chest cavity. The majority of Bochdalek hernias (80–85%) occur on the left side of the diaphragm, a large proportion of the remaining cases occur on the right side. To date, it carries a high mortality and an active area of clinical research Morgagni hernia This rare anterior defect of the diaphragm is variably referred to as Morgagni, retrosternal, or parasternal hernia. Accounting for approximately 2% of all CDH cases, it is characterized by herniation through the foramina of Morgagni which are located immediately adjacent and posterior to the xiphoid process of the sternum .

8. Diaphragm eventration The diagnosis of congenital diaphragmatic eventration is used when there is abnormal displacement (i.e. elevation ) of part or all of an otherwise intact diaphragm into the chest cavity . This rare type of CDH occurs because in the region of eventration the diaphragm is thinner, allowing the abdominal viscera to protrude upwards.

9. Pathogenesis CDH is thought to result from failure of closure of the pleuro- peritoneal canal in the developing fetus. Normally, the pleuroperi- toneal cavities become separated by the developing membrane during weeks 8 to 10 of gestation . When this process fails , the pleuroperitoneal canal does not close , and a posterolateral dia- phragmatic defect results. The p osterolateral location of this hernia is known as Bochdalek hernia ; it is distinguished from a CDH of the anteromedial location known as Morgagni hernia . As a result of the defect, abdominal contents herniate into the thoracic cavity, compressing the ipsilateral developing lung . These lungs have smaller bronchi , with less bronchial branching and less alveolar surface area than lungs in normal infants. The ipsilateral lung is affected more severely; however, both lungs are affected by pulmonary hypoplasia . In addition to the abnormal airway development, the pulmonary vasculature is also significantly affected by increased thickness of arteriolar smooth muscle . Also, arteriolar vasculature is extremely sensitive to the multiple local and systemic vasoactive factors. Hence, the severity of pulmonary hypoplasia and pulmonary hypertension significantly affect the overall morbidity and mortality in CDH infants.

10. Clinical Presentation and Diagnosis Most infants with CDH experience respiratory distress at birth. The initial symptoms and signs may include grunting respiration chest retractions dyspnea cyanosis with scaphoid abdomen. Decreased breath sounds along with bowel sounds may be auscultated over the chest with CDH The shifting of heart sounds to the right (for left-sided CDH) is common. A significant differential of preductal and postductal pulse oximetry indicates the right-to-left shunting due to PPHN.

11. The diagnosis of CDH is frequently made prenatally as early as 15 weeks of gestation during a routine ultrasound evaluation. Infants who have a late onset of CDH ( beyond 25 weeks of gestation) have been reported to have better overall survival . The herniation of the stomach and liver, polyhydramnios, and associated anomalies have been associated with poor outcome. The chest radiograph demonstrates multiple bowel loops in the thoracic cavity along with mediastinal shift. In Morgagni hernia , the diagnosis is often delayed until childhood because most infants are asymptomatic. Typically, the infant does well for several hours after delivery during the so-called honeymoon period and then begins to demonstrate worsening respiratory function. In approximately 10% to 20% of cases, CDH is diagnosed beyond the first 24 hours of life, at which time infants present with various symptoms of feeding difficulties, respiratory distress, and pneumonia.

12. Imaging Studies: Level III ultrasonography and echocardiography should accompany a diagnosis of CDH. Prenatal echocardiography may identify cardiac anomalies (more commonly, ventricular hypoplasia, atrial septal defects, and ventricular septal defects) Chest radiography An early chest radiograph is obtained to confirm the diagnosis of CDH. Findings include loops of bowel in the chest, mediastinal shift, paucity of bowel gas in the abdomen, and presence of the tip of a nasogastric tube in the thoracic stomach. Repeated chest radiographs may reveal a change in the intrathoracic gas pattern. Right-sided lesions are difficult to differentiate from diaphragmatic eventration and lobar consolidation. Echocardiography Further investigations should include early echocardiography, which may reveal cardiac defects, decreased left ventricular mass, poor ventricular contractility, pulmonary and tricuspid valve regurgitation, and right-to-left shunting. Repeated echocardiography is recommended to measure changes in the pulmonary artery pressure, left-to-right shunt, and flow across the ductus arteriosus.

13. TREATMENT Laparoscopic occlusion of the fetal trachea, resulting in accumulation of lung fluid to stimulate lung growth , has gained increasing interest. External tracheal clips or endotracheal balloons can be placed laparoscopically (often referred to as fetoscopy ) to occlude the fetal trachea. The Tracheal Occlusion To Accelerate Lung growth (TOTAL) trial is led by several European centres. The post- natal management of CDH is directed toward stabilization of the cardiorespiratory status while minimizing iatrogenic injury from therapeutic interventions. Immediate securing of the airway with endotracheal intubation is critical. Excessive mean airway pressure ventilation can result in pneumothorax and compromised venous blood return to the heart. The first step in management is orogastric tube placement and securing the airway (intubation). Inhaled nitric oxide is used widely for its pulmonary vasodilatory effect. Sildenafil , a phosphodiesterase type 5 inhibitor, works by inducing pulmonary vascular smooth muscle relaxation and has been used in many centers with various results.

14. Surgical Repair For infants with relatively stable pulmonary status, CDH repair can be safely performed on the second to fourth day of life after the potential honeymoon period. CDH repair after ECMO is associated with improved survival compared with repair while on ECMO. At operation, the preferred approach for a posterolateral CDH is through a subcostal abdominal incision . The viscera are reduced into the abdominal cavity, and the pos- terolateral defect in the diaphragm is approximated with interrupted nonabsorbable sutures. When present (10% to 15% of cases), a hernia sac should be excised . Typically, the hernia defect is large, with only a small leaflet of diaphragmatic tissue present anteromedially. Although primary repair of the defect is ideal, closure with excessive tension must be avoided to prevent hernia recurrence.

15. A number of reconstructive techniques and materials are available for the repair of large hernia defects. The surgical technique of abdominal or thoracic muscle flaps can be considered, but the use of prosthetic material , most commonly Gore-Tex patch , has become widespread The advantages of a prosthetic patch are shorter operative tim e and a tension-free repair . However, the major potential problems with prosthetic patches are the risks of infection and recurrence of the hernia . When CDH is repaired on ECMO, particular attention must be paid to achieve hemostasis . However, despite the use of careful surgical techniques with diligent hemostasis, postoperative bleeding is a common major complication . Beyond the immediate postoperative period, many infants with CDH experience significant morbidity because of PPHN and respiratory dysfunction . For example, infants who survive aggressive management of severe respiratory failure may manifest neurologic problems, such as motor and cognitive deficits, developmental delay, seizures, and hearing loss. Other problems include gastroesophageal reflux (GER) disease and foregut dysmotility.

16. Complications Complications observed in the early post operative period include recurrent pulmonary hypertension and a deterioration in respiratory mechanics and gaseous exchange Less commonly observed complications are the disruption of suture line, recurrence of diaphragmatic hernia, leakage of peritoneal fluid and blood into the thorax and development of an ipsilateral hydrothorax Small bowel obstruction may occur secondary to adhesions or volvulus

17. – Group 20 “THANK YOU”