Congenital Esophageal Stenosis

Congenital esophageal stenosis is a rare condition. The stenosis is frequently within 2 cm of the

gastroesophageal junction. The true incidence is unknown but is report to be 1:25,000 to 1:50,000 live

births. The narrowing of the lumen is present at birth but may not present with clinical symptoms

immediately. There are three histologic subtypes: ectopic tracheobronchial remnants, segmental

fibromuscular hypertrophy, and a membranous diaphragm or stenosis. These have been associated with

esophageal atresia. Symptoms may only occur when solids are started. Diagnosis is by esophagograms.

CT scans may confirm the diagnosis. Esophagoscopy confirms the diagnosis. Initial management is

esophageal dilation. If the stenosis is due to respiratory tract remnants, need for surgery is more

common. Surgery consists of resection of the stenotic segment with end-to-end anastomosis.114

Esophageal Duplication

Esophageal duplications are found in the posterior mediastinum and are covered by a muscular wall.

Most of these are attached to the wall of the esophagus and are covered by smooth muscle.

Approximately 10% communicate with the lumen of the esophagus. Neurenteric cysts communicate with

the spinal canal. Although many are asymptomatic, they may present with airway or esophageal

compression. In older children and adults, the presentation may be dysphagia, retrosternal pain, and

epigastric discomfort. There are reports of bleeding from acid dyspepsia. Excision is recommended

which may be accomplished by thoracotomy or thoracoscopy (Fig. 102-15).53,54

Vascular Rings

Vascular rings are a set of congenital defects in which the trachea or esophagus are encircled and

compressed by vascular structures. These account for approximately 1% of all congenital cardiovascular

anomalies. These rings may lead to tracheal narrowing with associated tracheomalacia. Symptoms may

include stridor, respiratory distress, or dysphagia. Barium swallow may be suggestive of the lesion. CT

scan and MRI are utilized to demonstrate the anomaly. Echocardiography is performed to rule out

structural cardiac anomalies. Bronchoscopy may also be useful to determine the degree of tracheal

narrowing. The most common type of abnormality is the double aortic arch resulting from persistence

of both the right and left embryologic aortic arches. The ascending aorta bifurcates, surrounding the

trachea and esophagus. Other causes of complete or incomplete rings include pulmonary artery sling

and aberrant right subclavian artery. When the vascular ring is symptomatic, the patient should be

treated by the appropriate division of the ring and lysis of the fibrous bands surrounding the trachea

and esophagus.115

Figure 102-15. Thoracoscopic excision of an esophageal duplication cyst in a patient presenting with dysphagia. Video endoscopic

view of the left superior hemithorax. (+) indicates site of original esophageal duplication cyst. Light from the intraesophageal

endoscope can be seen. Arrows demonstrate the subclavian artery. The mass (*) is nearly excised.

Congenital Tracheal Stenosis

Congenital tracheal stenosis represents a spectrum of obstructive lesions most commonly treated with

operative repair. The etiologies include complete tracheal rings, compression from anomalous

cardiovascular anatomy, and tracheomalacia. Short stenosis may respond to resection and anastomosis.

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Longer lengths of stenosis can be managed by patch tracheoplasty and slide tracheoplasty. Use of

cardiopulmonary bypass during repair may improve outcomes. In a review article outcomes were

similar with the use of slide tracheoplasty and patch tracheoplasty.116,117

FOREIGN BODIES OF THE TRACHEOBRONCHIAL TREE

9 Foreign-body aspiration occurs commonly in infants and young children and is a potentially lifethreatening event. A report in 2001 found that nonfood choking was a cause of death for 449 persons

under the age of 14 with 65% of the deaths in children under 3 over a 20-year period. Choking on food

causes death of approximately 75 children per year. Management is with the Hopkins rod lens system

with fiberoptic illumination utilized with rigid pediatric bronchoscopes and specialized grasping devices

allows for safe and reliable extraction of foreign bodies.118–120

Pathophysiology

Complete airway obstruction can occur at the level of the pharynx, hypopharynx, or trachea. Back

blows, abdominal thrust, or the Heimlich maneuver may dislodge the obstruction and save a life. An

inhaled foreign body which reaches the bronchial level may cause a ball-valve phenomenon allowing bidirectional but unequal flow of air. Air trapping and hyperinflation of the affected lobe lead to

mediastinal shift. Complete blockage results in loss of volume due to atelectasis.

Foods are the most common aspirated items and include peanuts, carrots, popcorn, hotdogs, and

grapes. Coins and toys are the most common nonfood items aspirated.

Clinical Presentation

Most affected children are less than 3 years of age. History of choking crisis is present in the majority of

children. Other symptoms include cough, wheezing, dyspnea, and fever. The most common signs are

unilateral decreased breath sounds, untilateral wheezing, and rhonchi.

Management

Chest radiographs, including bilateral lateral decubitus films are performed unless the patient is in

respiratory distress. The films may demonstrate hyperinflation or failure to develop atelectasis on the

affected side. In addition, the films may show pneumonia or atelectasis with a completely occluding

foreign body.

Bronchoscopic evaluation and foreign-body removal is performed in the operating room under

general anesthesia. The rigid bronchoscope with optical forceps can be used to retrieve most aspirated

foreign bodies (Fig. 102-16). Flexible graspers, Fogarty balloon catheters, and baskets can be useful

especially if the foreign body has migrated distally or has a smooth or round surface. Fluoroscopic

assistance can be useful with radiopaque objects which have migrated into the peripheral airways.

Over time, pneumonia or atelectasis may develop and a foreign body presenting with chronic lung

infection will require surgical resection of the associated potion of the lung.

CONGENITAL ABNORMALITIES OF THE DIAPHRAGM

10 Developmental defects of the diaphragm have surgical implications. Advances in management of

neonatal respiratory failure, fetal surgery, and lung developmental biology have arisen from the clinical

and laboratory evaluation of CDH (CDH, Bochdalek, or posterolateral hernia). CDH, which is relatively

rare, occurring in 1 in 3,000 neonates has led to a significant amount of clinical and basic science

research.

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Figure 102-16. Schematic illustration of a peanut foreign body being extracted from the right main stem bronchus under direct

vision.

In 1754, McCauley described the clinical course and postmortem anatomy of an infant with CDH.121

Although Bochdalek’s

122 understanding of the embryology of CDH was incorrect, this congenital defect

continues to carry his name. Prior to 1940, the successful repair of this defect remained rare.123 In 1946,

Gross

124 reported the postoperative survival of an infant less than 24 hours of age. From that time until

the 1980s the standard of care was emergent operative repair. At that time, CDH was considered to be

an anatomic derangement treated by an anatomic correction (the thought was that by getting the bowel

out of the chest, the lung compression would improve and the outcome would improve).

Until the 1980s, emergency surgery was considered the primary therapeutic goal based on mechanical

concept of providing space for growth of lungs. The overall published survival rates in the 1980s were

50% with ranges from 20% to 70% based on case selection. In the late 1980s, there was a switch in

management from emergency surgery to stabilization.125 Management in the postnatal period is

directed at decreasing pulmonary hypertension while maintaining adequate oxygen saturations

(between 85% and 95% preductal).125,126 Surgical repair is deferred until after physiologic stabilization

and this has led to improved survival of infant with CDH. Further improvements in therapies for

pulmonary hypertension and method to increase lung growth to combat pulmonary hypoplasia should

result in improvement in the survival and decreased morbidity of CDH infants.

Embryology of the Diaphragm

Mammalian lung development occurs in vivo as a coordinated developmental process that includes (a)

airway and acinar development, (b) cellular differentiation, (c) biochemical maturation, (d) interstitial

development including vasculature and extracellular matrix, and (e) physical growth or enlargement.

These parallel developmental processes occur in such a fashion that at any one time during

development, there are characteristic relationships among each component that define the so-called

stages of lung development.127–129 Hormones such as the glucocorticoids, thyroid hormone, and retinoic

acid have been shown to regulate several of the crucial cellular interactions required for proper

pulmonary organogenesis and differentiation. In the human embryo, respiratory tract development

begins in the fourth week of gestation as a ventral out pouching of the foregut that soon has bifurcated

and begun branching into the surrounding mesenchyme. The primitive, pluripotent epithelial cells

differentiate into both bronchial and alveolar cell lines, under the control of the surrounding

mesenchyme. By a process of asymmetric branching, the divisions are complete by the 16th week of

gestation. Lung at this phase has columnar epithelium with thick mesenchyme giving rise to the

descriptive term pseudoglandular phase of development because of its histologic appearance. The

canalicular phase that follows and continues up to about the 24th gestational week is characterized by

flattening of the epithelium of the distal airways, thinning of the mesenchyme, and the growth of the

capillary network that surrounds the terminal airways. Gas exchange becomes functionally possible at

the end of this phase. The terminal sac period that follows refers to the appearance of a thin respiratory

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epithelium in apposition to a capillary network capable of supporting gas exchange. True alveolar

formation in humans begins shortly before or around the time of birth. Alveolar maturation and

multiplication takes place after birth and may continue up to 8 years of age.

The precursors of the mesoderm-derived diaphragm begin to form during the fourth week of

gestation with the appearance of the peritoneal folds from lateral mesenchymal tissue. At the same

time, the septum transversum forms from the inferior portion of the pericardial cavity and serves to

delineate the thoracic from the abdominal cavities. Eventually, the septum transversum leads to the

formation of the central tendinous area of the fully developed diaphragm. The pleuroperitoneal folds

extend from the lateral body wall and grow medially and ventrally until they fuse with the septum

transversum and dorsal mesentery of the esophagus during the sixth gestational week. Complete closure

of the canal takes place during the eighth week of gestation, with the right side closing before the

left.130 Muscularization of the diaphragm appears to develop from the innermost layer of thoracic

mesoderm, although other mechanisms have been proposed.131 Nitrofen-induced diaphragmatic hernias

in rats have been studied with scanning electron microscopy. Normal diaphragmatic development

includes the development of the pleuroperitoneal fold which connects to the mesonephric ridge and

transverse septum. The lung buds protrude into the peritoneal cavity and come in close contact with the

liver on the right and the stomach on the left. The lungs follow the enlarging pleural cavities and the

peritoneal portion becomes smaller. A trapezoidal structure forms laterally and is defined as the

posthepatic mesenchymal plate (PHMP). The PHMP grows rapidly in a laterodorsal direction and forms

the prominent ridge covering part of the liver. The opening closes from a continuous ingrowth of the

PHMP.132 In diaphragmatic hernia development, the PHMP is smaller and malformed although the

pleuroperitoneal fold and the transverse septum appear normal. This leaves part of the liver uncovered

and can bulge into the thorax. The lung development proceeds normally until the liver and lung

approach each other and lung hypoplasia is related to the degree of herniation (Fig. 102-17).132

Congenital Diaphragmatic Hernia Pathology and Pathophysiology

CDH occurs in 1:3,000 to 2:4,000 live births. Approximately one-third of antenatally diagnosed infants

with CDH are stillborn, with most of the deaths subscribed to other fatal anomalies. Defects are more

common on the left side based on the CDH registry.133 CDH represents a sporadic developmental

anomaly with some familial cases reported. One-third of patients have associated major defects. CDH

associated with an abnormal karyotype or cardiac defect is associated with a poor outcome.134

Figure 102-17. Anatomy of the diaphragm showing the location of congenital diaphragmatic defects.

The cause of CDH is unknown but is presumed that some combination of intrinsic predisposition

(genetic factors) and environmental factors (teratogen or deficiency) results in abnormal diaphragm and

lung development.135 A nitrofen-induced model of CDH also inhibits retinal dehydrogenase leading to

decreased retinoic acid, which has also been found in human infants with CDH.

During the early development of the diaphragm, the midgut is largely extracoelomic. If closure of the

pleuroperitoneal canal has not occurred by the time the midgut returns to the abdomen during the 9th

and 10th weeks of gestation, the abdominal viscera herniate through the lumbocostal trigone into the

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ipsilateral thoracic cavity. The resulting abnormal position of the bowel prevents its normal

counterclockwise rotation and fixation. No hernia sac is present if the event occurs before complete

closure of the pleuroperitoneal canal, but a nonmuscularized membrane forms a hernia sac in 10% to

15% of CDH patients. In addition to the small bowel, other intraabdominal organs such as the spleen,

stomach, colon, and liver may also herniate through the diaphragmatic defect.

Left-sided CDH is characterized by a 2- to 4-cm posterolateral defect in the diaphragm through which

the abdominal viscera have translocated into the ipsilateral thoracic cavity. On a right-sided defect, the

large right lobe of the liver can occupy most of the hemithorax. The hepatic veins may drain ectopically

into the right atrium, and the liver and lung may be fused.135

The pathophysiology of CDH has been attributed to pulmonary parenchymal compression by the

herniated organs and its effect on growth and maturation of the lung. An emerging school of thought

attributes the pulmonary hypoplasia to an early mesenchymal developmental insult to the lung and

diaphragm. Unilateral diaphragmatic hernia is associated with both ipsilateral and contralateral

abnormal pulmonary development, although hypoplasia is more severe on the ipsilateral side. The lung

on the side of the hernia is much smaller than its contralateral counterpart, and both are strikingly

smaller than normal lungs (Fig. 102-18). The pulmonary vascular disease associated with CDH is

characterized by abnormal pulmonary vascular development, abnormal vasoreactivity, and a

disorganization of postnatal vascular remodeling. There are fewer capillaries which are unevenly

distributed. Both the media and the adventitia have structural abnormalities consistent with increased

muscularization in utero. Sonic hedgehog signaling which is involved in the development of respiratory

bronchioles is delayed in CDH. Levels of several regulatory proteins are changed compared to controls

but no causative relationship has been demonstrated.136,137

Pulmonary blood flow accounts for only 7% of cardiac output during normal fetal development.

Pulmonary vascular resistance is high. The fetus preferentially shunts oxygenated blood from the

placenta through the foramen ovale and ductus arteriosus in a right-to-left direction into the systemic

circulation. With the institution of breathing at birth, oxygen levels rise causing pulmonary vascular

resistance to fall, which in turn allows an increase in pulmonary blood flow. Increased arterial oxygen

tension then also induces spontaneous closure of the ductus arteriosus. Persistent fetal circulation may

develop if this process is interrupted. Elevated pulmonary vascular resistance results in right-to-left

shunting of blood at either the atrial or ductal levels with the delivery of unsaturated blood into the

systemic circulation. As shunting increases, the oxygen saturation in the systemic circulation falls. The

resulting hypoxia further increases pulmonary vascular resistance and compromises pulmonary blood

flow while increasing the right-to-left shunt flow. Factors that contribute to the persistence of high

pulmonary vascular resistance in CDH lungs are thought to be the structural changes of decreased total

arteriolar cross-sectional area in the involved lungs and the increased muscularization of the arterial

structures that are present. Additional exacerbations of pulmonary vascular resistance may be induced

by the known stimulators of pulmonary hypertension, which include hypoxia, acidosis, hypothermia,

and stress. Alternations in the levels of prostaglandins, leukotrienes, catecholamines, and the renin

angiotensin system had been implicated as mediators of this complex process. The combination of

hypoplastic lungs and lungs prone toward increased vascular resistance often proves to be deadly; a

vicious cycle may ensue in which hypoplastic lungs and associated hypoxia leads to pulmonary

hypertension in a lung vasculature already prone toward reactive vasospasm. The increase in pulmonary

pressures results in a greater shunt, which in turn further reduces oxygen levels.

2933

Figure 102-18. Autopsy specimen of an infant with severe pulmonary hypoplasia secondary to congenital diaphragmatic hernia.

Pulmonary hypoplasia is bilateral, but the left lung is most severely affected.

Diagnosis

Diagnosis of CDH is often made on prenatal ultrasound examination and a recent population-based study

demonstrated that 66% were diagnosed prenatally.138 In addition to the defect, polyhydramnios is

common. Prenatal MRI is utilized for more accurate delineation of the defect.125 Postnatal presentation

frequently includes cyanosis and respiratory distress shortly after birth in severely affected neonates. On

physical examination, the patients have a scaphoid abdomen. A plain chest radiograph with loops of

intestine in the chest confirms the diagnosis of CDH with an ng tube in place to confirm the position of

the stomach (Fig. 102-19). After confirmation of diagnosis, echocardiography should be performed to

evaluate for degree of pulmonary hypertension and to determine presence of cardiac defects.

Differential diagnosis includes eventration of the diaphragm, anterior diaphragmatic hernia (Morgagni),

congenital pulmonary malformations, unilateral pulmonary effusion, and primary agenesis of the

lung.139

Figure 102-19. A: Chest radiograph of a newborn with a left congenital diaphragmatic hernia. Mediastinal structures are shifted to

the right. Abdominal viscera occupy the left hemithorax. The nasogastric tube locates the stomach. The child underwent repair of

the congenital diaphragmatic hernia after treatment and resolution of pulmonary hypertension. B: Immediate postoperative

photograph demonstrates hypoplastic lung, flattening of diaphragm, and return of abdominal viscera to normal positon.

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Prognostic Factors

Multiple tools for prognosis of CDH have not been successful. One method for evaluation is the lung to

head ratio (LHR) which is determined by multiplying the simultaneous sonographic measurements of

the size if the contralateral lung in an anteroposterior and lateromedial direction, and dividing by the

head circumference. Ratios less than 1 have been associated with poor outcome. Because the LHR

increases with age, the percent of predicted value for gestational age has been used with no survivors

below 15% of predicted.140 Liver above the diaphragm has also been used to determine outcome with

decreased survival with liver-up. The combination of a low LHR with liver-up has a poor outcome. The

size of the defect was a significant factor in survival, a major cardiac anomaly and 1-minute Apgar sores

of ≤4 were associated with increased mortality.141,142 Physiologic parameters have been used to

develop calculations for prediction of survival including the CDHSG which utilizes birthweight and 5-

minute Apgar, the CNN (Canadian Neonatal Network) equation utilizing SNAP-II scores and gestational

age, and the WHSRPF using blood gas values in first 24 hours, with the CDHSG having the best

predictive value.138

Treatment

At the time of antenatal diagnosis, the mother and fetus should be referred to an appropriate tertiary

care perinatal center with the availability of the full array of respiratory care strategies.

Resuscitation should begin with standard neonatal resuscitation guidelines and then proceed with

endotracheal intubation and nasogastric tube insertion. Bag–valve mask should be avoided. Careful

management of temperature regulation, glucose homeostasis, and volume status should be performed.

Fluid resuscitation should be performed with crystalloid, blood products, and colloid. Inotropes such as

dopamine or dobutamine are utilized if needed. Most infants can be managed with simple pressurecycled ventilation with a goal of maintaining a preductal PaO2 greater than 60 correlating with

saturation between 85% and 95%. Keeping peak pressures below 25 and accepting CO2 between 45 and

65 decreases barotrauma. For failure of gentle ventilation, the next step in therapy would be the use of

jet ventilator or oscillator ventilator; use of HFOV with mean airway pressure 13 to 17, frequency of 10

Hz, and amplitude of 30 to 50 keeping the contralateral lung expansion at 8 ribs.126

In addition to ventilatory methods, a variety of agents are utilized to modify pulmonary vascular

resistance. Inhaled nitric oxide has been used in infants with approximately 30% responding. Studies

have demonstrated that the results are temporary and NO should be considered a temporizing measure.

Phosphodiesterase-5 inhibition with sildenafil has a vasodilatory effect but can also cause systemic

hypotension worsening the shunting. In addition, the absorption is variable so dose–effect relationship is

not well understood. Milrinone, a phosphodiesterase-3 inhibitor improves right ventricular function and

relaxes pulmonary vessels but there is no evidence to support or discourage the use of milrinone. Recent

studies have demonstrated the use of prostacyclin or prostaglandin E1 to decrease pulmonary artery

pressure and pulmonary vascular resistance. Inhalation of prostacyclin seems to be preferable to IV

usage. Other medications such as tyrosine kinase inhibitors and endothelin receptor antagonists may

show promise.136

Surfactant has been demonstrated to be reduced in CDH infants. However, surfactant has not been

demonstrated to improve survival.143

Failure to improve with ventilatory and pulmonary hypertension management strategies should

prompt consideration of ECMO. ECMO can be used for an extended period of time when ventilator

therapy has failed. Indication for the use of ECMO is the failure to improve in the setting of severe

pulmonary hypertension. In recent years the use of ECMO has decreased but still ranges from 15% to

40% of diaphragmatic hernias; with survival following ECMO of 51%.125

Surgery

Delayed surgery has been demonstrated to improve survival in some studies. Current consensus is that

the repair should be done in a semielective manner.

The diaphragm defect is usually approached through a subcostal incision, although the repair can be

performed through a thoracotomy incision (Fig. 102-20). Both thoracoscopic and laparoscopic

approaches have been described. The abdominal organs are returned to the abdomen. The defect in the

diaphragm is repaired. Primary repair with nonabsorbale suture is preferred. If the defect cannot be

repaired primarily due to size, a prosthetic patch such as Goretex has been utilized. The major drawback

of the use of a patch, either inert or bioactive is recurrent herniation which may occur in up to 50% of

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infants.144 There may have been loss of intraabdominal domain and difficulty with closing the abdomen.

In these cases, a silo may be used.145 Tube thoracostomy is used at the surgeon preference. A recent

meta-analysis of minimally invasive versus open repairs demonstrated that recurrence rate is higher

after MIS and operative time is longer.146 Postoperative ventilator time and postoperative mortality

were higher after open surgery but none of the studies were randomized and this may have represented

selection bias.146

Figure 102-20. Repair of a congenital diaphragmatic hernia (CDH). A: Operative appearance of CDH. B: Placement of sutures for

repair of a typical left posterolateral diaphragmatic defect. C: Completed repair. D: Prosthetic material may be used for large

defects to avoid tension.

Postoperative management should continue the goals set before surgery. Continued attention to fluid

status is important in the postoperative period. Weaning from the ventilator should be slow and

deliberate. Refractory postoperative pulmonary hypertension is relatively common in those who

required ECMO and is often treated with iNO and prostacyclin in conjunction with frequent

echocardiography.

Outcome

Survival rates have been reported at 65% to 78% in the last decade improved from 50% in the past. As

survival has improved, other morbidities have been demonstrated including long-term use of

bronchodilators, need for gastrostomy for nutritional support, and increased rate of GERD requiring

surgery. Musculoskeletal deformities also occur with scoliosis, pectus excavatum, pectus carinatum, and

chest wall asymmetry described.147 Adult survivors of CDH have demonstrated higher incidence of

GERD, recurrent intestinal obstruction, and recurrent abdominal pain. Scores in the Gastrointestinal

Quality of Life Index are similar to controls while there were lower scores in the Health-related Quality

of Life Survey but most still had good or satisfactory scores.148

Evolving Therapies

Open fetal repair of diaphragmatic hernia has been performed but there was no survival benefit and

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there was an increase in preterm delivery so this is not currently offered. Tracheal occlusion in utero

has been developed as a strategy based on observations that the lungs of neonates with congenital high

airway obstruction developed hyperplastic lungs. Fetal tracheal occlusion improved lung volume but

there was still impairment in the lung. Fetal endoscopic tracheal occlusion has been trialed with fewer

premature deliveries. In the US trial there was no improvement in survival in a randomized trial. The

European trials add a second fetal surgery to remove the balloon to allow for improvement in the

development and function of type II pneumocytes and to increase surfactant production. With the

European trial, vaginal delivery is possible but with the US trial, the infants were delivered by EXIT

procedure, using the placenta to maintain oxygenation until an airway is secured.140

Foramen of Morgagni Hernia

The anterior CDH is rare and accounts for 3% to 5% of all CDHs. It is commonly diagnosed during

childhood. It is frequently diagnosed from chest or abdominal radiographs being performed for

presumed pneumonia or gastrointestinal symptoms (Fig. 102-21).149 This is an anteromedial hernia at

the junction of the septum transversum and the thoracic wall with contents being seen in a retrosternal

position. There is a hernia sac present and the sac may contain colon, small intestine, or liver. The

hernias are repaired due to the risk of segmental intestinal volvulus or obstruction. Repair may be

performed through a laparoscopic approach. The sac is excised and the diaphragm is sutured to the

undersurface of the posterior rectus sheath at the costal margin. Laparoscopy has been demonstrated to

be an effective method for repair of this type of hernia.150,151

Figure 102-21. Morgagni hernia. (A) Anteroposterior and (B), lateral radiographs of patient with Morgagni hernia.

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Eventration of the Diaphragm

Eventration of the diaphragm is diagnosed by the abnormal elevation of one or both hemidiaphragms

and can be congenital or acquired. The congenital form may appear very similar to a diaphragmatic

hernia with a sac. The cause of the congenital form is unknown although infectious causes have been

implicated. The acquired form is a consequence of injury to the phrenic nerve. Small children are more

likely to be affected than older children as the decreased chest size leads to dyspnea and respiratory

infection. Surgery is utilized for symptomatic cases after several months of observation if symptoms are

minimal. The surgical management is with plication of the diaphragm with nonabsorbale sutures. The

repair may be performed through the abdomen or the chest and both thoracoscopic and laparoscopic

techniques are applicable.152

Diaphragmatic Pacing

Ventilator-dependent children with spinal cord injury or central hypoventilation syndromes may benefit

from diaphragm pacing.153 The application of repetitive stimulus patterns to the phrenic nerves causes

rhythmic contractions of the diaphragm. Phrenic nerve pacing wires are implanted at the cervical or

intrathoracic level. Receivers are implanted in subcutaneous pockets, while an external microprocessorcontrolled transmitter/antenna assembly activates the receiver. Patients with injured phrenic nerves

(high spinal cord injury) may benefit from diaphragm pacing after intercostal-to-phrenic nerve

transfer.154

PLEURAL DISEASES

Empyema

Empyema is the accumulation of purulent material in the pleural space. In children, empyema is most

often the sequelae of bacterial pneumonia. Empyema develops when a parapneumonic effusion becomes

infected or when a necrotizing pneumonia erodes into the pleural space. Empyema may also be caused

by penetrating thoracic trauma, intrathroacic, or cervical esophageal perforation or as a complication

from surgery on the chest. The American Thoracic Society divides the empyema process into 3 stages:

1. Exudative: Thin free-flowing fluid with a low cell count.

2. Fibrinopurulent: Frank pus is present and fibrin formation begins to cover the pleura with

development of loculations.

3. Organizing: Thick peel with fibroblasts.155

The most common organism responsible for empyema is Streptococcus pneumonia despite the

utilization of pneumococcal vaccinations. Other common organisms are Staphylococcus aureus and

Hemophilus influenza.156 The signs and symptoms include worsening pneumonia with fever, tachypnea,

dyspnea, and sometimes cyanosis. Abdominal pain may be present. Chest radiograph demonstrates the

presence of fluid and loculation. CT imaging is the best method of determining the extent of loculated

fluid versus underlying pulmonary pathology (Fig. 102-22).

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