Pediatric Surgery

INTRODUCTION

Pediatric surgery combines the technical challenge of performing complex operations in neonates, the appeal of solving a wide array of problems in many anatomic locations, and

the immense satisfaction of caring for children and offering them a long normal life. The approach to surgical problems in children should consider the long-term effects of the

therapy as well as its immediate success rate. The resiliency of children to major surgical stress must always be balanced against their intolerance to inaccurate fluid and

medication administration. The gratitude of a parent whose child has been saved by surgery is an additional benefit of this unique specialty.

GENERAL CONSIDERATIONS

Fluid and Electrolyte Balance

In an infant or child, the margin between dehydration and fluid overload is small. The infant is born with a surplus of body water, but within a few days this is excreted. At birth and

for the first 10 days of life, fluid requirements are 65 to 100 mL/kg (750 to 1000 mL/m 2). Daily maintenance fluids can be calculated by the formula: 100 mL/kg up to 10 kg, add 50

mL/kg for 11 to 20 kg, and add 25 mL/kg for each kilogram of weight thereafter. Because I.V. fluid orders are written as milliliters per hour, this can be conveniently converted to 4

mL/kg/h up to 10 kg, add 2 mL/kg/h for 11 to 20 kg, and add 1 mL/kg/h for each additional kilogram. For example, a 26-kg child has a maintenance fluid requirement of (10 × 4) +

(10 × 2) + (6 × 1) = 66 mL/h. Fluid for maintenance is generally provided as 5% dextrose in ¼ or [frac13] normal saline. For short-term intravenous therapy, sodium 5 meq/kg/day

and potassium 2 meq/kg/day will satisfy the daily need. Fluid and electrolyte losses secondary to protracted vomiting or diarrhea are corrected by modifying this formula according

to the measured losses. In the infant the normal serum osmolarity is between 280 and 290 mO/L.

Newborns have the ability to concentrate their urine well by the fifth day of life; thus urine concentration as well as output must be considered when ordering I.V. fluids

postoperatively. Daily electrolyte determinations are performed in infants on I.V. alimentation to obviate the serious sequelae of hypoosmolarity or hyperosmolarity. If the child has a

significant ongoing fluid loss (e.g., from a nasogastric tube), it is best to properly replace that loss with I.V. fluids at least every 8h.

Whatever the formula used to calculate fluid replacement for the infant or small child, there is no substitute for collecting and analyzing fluid losses and replacing the depleted

constituents precisely.

Acid-Base Equilibrium

Acidosis in children is an ominous sign unless it is the result of a chronic bicarbonate loss from the gastrointestinal tract or an acid accumulation as in chronic renal failure. Acute

acidosis usually implies inadequate tissue perfusion, and the cause of acidosis must be sought. Treatment of acute acidosis with a base deficit of greater than 5 is to administer

sodium bicarbonate in the following dose: base deficit × weight in kilograms × 0.5 (in newborns). In small children, the last factor in the equation should be 0.4, and it should be 0.3

in older children. The dose should be diluted to 0.5 meq/mL because full-strength sodium bicarbonate is hyperosmolar. One-half the corrective dose is given, and the serum pH is

measured again. During cardiopulmonary resuscitation (CPR), one-half the corrective dose can be given as an I.V. bolus and the other half given slowly I.V.

Alkalosis is usually caused by hyperventilation or stomach acid loss. In the ventilated child, hyperventilation can be corrected easily by decreasing the respiratory rate or tidal

volume. In the child with gastric fluid loss, I.V. fluids of 5% dextrose, 0.5% normal saline, and 20 mEq KCl/L usually correct the alkalosis. This is the preferred replacement fluid in

children with pyloric stenosis and alkalosis.

Blood Volume and Blood Replacement

A useful guideline for estimation of blood volume for the infant is 85 mL/kg of body weight. When packed red blood cells are utilized, the transfusion requirement is calculated as 10

mL/kg, which roughly is equivalent to a 500-mL transfusion for a 70-kg adult. In the child, coagulation deficiencies rapidly may assume clinical significance after extensive blood

transfusion. It is advisable to have fresh frozen plasma and platelets available if more than 30 mL/kg have been transfused. Plasma is given in a dose of 20 mL/kg and platelets are

given in a dose of 1 unit/5 kg. Each unit of platelets consists of 40 to 60 mL of fluid and the platelets can be spun down to a platelet “button” in infants who require restricted fluid

administration.

Hyperalimentation and Nutrition

The physiologic nutritional demands imposed on the growing infant are well recognized. When these are compounded by illness and the need to repair tissue and heal surgical

wounds, the risks of protein-calorie malnutrition are considerable. Thus parenteral nutritional support has been integrated into the management of infants and children with surgical

illnesses. When the gastrointestinal tract is not usable because of mechanical, ischemic, or inflammatory disorders, several options for nutritional support are available. Techniques

for delivering calories by a central or a peripheral venous route have been refined to the point where the caloric needs of all patients can be satisfied. Central venous catheters

continue to be the most common route for administering I.V. hyperalimentation for an extended period of time. Peripheral I.V. alimentation, utilizing less concentrated but greater

volumes of solutions, in combination with I.V. lipid supplements has eliminated the need for central alimentation in some patients. The infusion of all solutions utilized for

alimentation, indeed any I.V. solution in an infant or small child, always should be controlled by a properly alarmed constant infusion pump. To prevent the development of trace

metal deficiencies, supplementary copper, zinc, and iron are provided to patients receiving long-term parenteral nutritional support.

By using these techniques, positive nitrogen balance can be accomplished for all infants and children. Refinements and advances in the techniques of parenteral nutrition have had

an enormous impact on the survival of pediatric surgical patients. Despite the remarkable advances in I.V. alimentation, enteral feeding is always the preferred route, and every

effort is made to use the gastrointestinal tract by mouth or by tube feeding as quickly as possible.

Venous Access

Obtaining reliable vascular access in an infant or child is a major responsibility of the pediatric surgeon. The goal always must be to place the catheter in the least invasive, least

risky, and least painful manner and in a location that is most likely to allow use of the catheter without complications for as long as needed. Regardless of the size of the patient,

most infants requiring short-term I.V. medications and nutrition can be managed by peripheral percutaneous I.V. catheter placement. For long- term I.V. access in small infants, use

of Silastic central venous catheters is best. These are usually placed by cutdown in infants and by a percutaneous technique in older children. When a central venous catheter is

placed by cutdown, the preferred sites are external jugular vein, facial vein, or proximal saphenous vein. Secondarily, the internal jugular vein may be used with a purse-string

suture placed at the venotomy site to prevent venous occlusion. The catheters are tunneled to an exit site separate from the venotomy site. Currently, most central venous catheter

placement by cutdown is done in the operating room under general anesthesia.

The percutaneous placement of central venous catheters in infants can be done with success in experienced hands. The risk of doing this procedure blindly in an infant always

must be weighed against the benefit of avoiding a venous cutdown. In the infant with multiple central venous lines placed by cutdowns, the percutaneous approach may be the only

reasonable option. Regardless of whether the catheter is placed by cutdown or percutaneously, a chest x-ray to confirm central location of the catheter tip and no chest

complication from the placement is mandatory. We do this routinely within the operating room before the child is awakened.

Despite the technologic advances in the design of small catheters, the complication rates for central venous lines in infants are high. Sepsis from the catheter approaches a 10

percent incidence in many series, and superior or inferior vena caval occlusion is a significant risk, particularly in the smallest premature patients. We make every effort to feed the

infants by the enteral route as soon and as completely as possible to minimize the length of time they depend on I.V. nutrition.

Thermoregulation

Infants or children compromised by disease are extremely thermolabile. Premature infants are particularly susceptible to changes in environmental temperature. Because they are

unable to shiver and lack stores of fat, their potential for thermogenesis is impaired. Since these patients lack adaptive mechanisms to cope with the environment, the environment

must be regulated. Attention to heat conservation during transport of the infant to and from the operating room is essential. Transport units incorporating heating units are

necessary for premature infants. In the operating room, the infant is kept warm by the use of overhead heating lamps, a heating blanket, warming of inspired gases, and coverage

of the extremities and head with occlusive materials. During abdominal surgery, it is best to use an adhesive plastic sheet to avoid sheets that are wet and cold. All fluids used to

irrigate the chest or abdomen must be warmed to body temperature. Constant monitoring of the child's temperature is critical in a lengthy procedure.

Pain Control

The various physiologic responses of both neonates and fetuses to painful stimuli have been studied, and the results refute a commonly held belief that such patients do not have

mature enough nervous systems to sense pain in a manner similar to adults. Despite concern that respiratory depression might result from administration of narcotic analgesics in

infants, if the medications are given in the proper dose and with a proper time interval, they have an acceptable safety margin. In our hospital, virtually all parenteral analgesics are

given intravenously. For all patients with an adequate understanding of the administration system, patient-controlled analgesia (PCA) is an excellent method of pain control. There is

no fixed age below which PCA is not offered; however, patients below the age of 7years generally are poor candidates for PCA.

Some attempts at parent-controlled analgesia have been made, but the emotional involvement of the parents and their desire to see the child pain- free rather than comfortable

have limited the usefulness of that approach. Whenever possible, the use of anesthetic blocks, such as caudal tetracaine for hernias or thoracic epidural blocks for chest surgery,

are encouraged. Two to three days of excellent pain relief can be obtained by epidural catheter administration of narcotics and/or local anesthetics, and such patients are monitored

closely postoperatively. All pediatric patients having surgery, including circumcision, have pain, and should be given appropriate analgesia by the appropriate route to control that

pain.

Minimally Invasive Surgery

New technology has allowed many procedures that traditionally were done as open procedures to be done using video-assisted, minimally invasive techniques in infants and

children, regardless of size. Laparoscopic cholecystectomy, splenectomy, Nissen fundoplication, appendectomy, and placement of peritoneal dialysis and ventriculoperitoneal

shunts are performed routinely with less morbidity than their open counterparts. Laparoscopic assessment of the asymptomic side in inguinal hernia and localization of the

nonpalpable testicle are also becoming commonplace.

Laparoscopic pyloromyotomy is comparable with the open technique, but not demonstrably superior. Thoracoscopy for evacuation of empyema, lung biopsy and thoracic mass

excision or biopsy also has gained wide acceptance in pediatric surgery.

LESIONS OF THE NECK

Thyroglossal Duct Remnants

Pathology and Clinical Manifestations

The thyroid gland buds off the foregut diverticulum at the base of the tongue in the region of the future foramen cecum at 3 weeks of embryonic life. As the fetal neck develops, the

thyroid tissue becomes more anterior and caudad until it rests in its normal position. The “descent” of the thyroid is intimately connected with the development of the hyoid bone.

Residual thyroid tissue left behind in the migration may persist and present in the midline of the neck as a thyroglossal duct cyst. The mass is most commonly appreciated in the 2-

to 4-year-old child when the baby fat subsides and irregularities in the neck are more readily apparent. Usually the cyst is encountered in the midline at or below the level of the

hyoid bone and moves up and down with swallowing or with protrusion of the tongue. Occasionally it presents as an intrathyroidal mass. Most thyroglossal duct cysts are

asymptomatic. If the duct retains its connection with the pharynx, infection may occur, and the resulting abscess will need drainage, occasionally resulting in a salivary fistula.

Submental lymphadenopathy and midline dermoid cysts can be confused with a thyroglossal duct cyst. Rarely, midline ectopic thyroid tissue masquerades as a thyroglossal duct

cyst and may represent the patient's only thyroid tissue. Therefore, if there is any question regarding the diagnosis or if the thyroid gland cannot be palpated in its normal anatomic

position, it is advisable to obtain a nuclear scan to confirm the presence of a normal thyroid gland. Although rarely the case in children, in adults the thyroglossal duct might contain

thyroid tissue that undergoes malignant degeneration.

Treatment

If the cyst presents with an abscess, treatment should consist of drainage and antibiotics. Following resolution of the inflammation, resection of the cyst in continuity with the central

portion of the hyoid, and the tract into the pharynx, plus ligation at the foramen cecum (the Sistrunk operation), is curative. Lesser operations result in unacceptably high recurrence

rates, and recurrence is more frequent following infection.

Branchial Cleft Anomalies

Paired branchial clefts and arches develop early in the fourth gestational week. The first cleft and the first, second, third and fourth pouches give rise to adult organs. The embryologic communication between the pharynx and the external surface may persist as a fistula . A fistula is seen most commonly with the second branchial cleft,

which normally disappears, and extends from the anterior border of the sternocleidomastoid muscle superiorly, inward through the bifurcation of the carotid artery, and enters the

posterolateral pharynx just below the tonsillar fossa. The branchial cleft remnants may contain small pieces of cartilage and cysts, but internal fistulas are rare. A second branchial

cleft sinus is suspected when clear fluid is noted draining from the external opening of the tract at the anterior border of the lower third of the sternomastoid muscle. The treatment

is surgical, and complete removal of the cyst and tract is necessary for cure. Dissection of the sinus tract is facilitated by passing a fine lacrimal duct probe through the external

opening into the tract and utilizing this as a guide for dissection. Injection of a small amount of methylene blue dye into the tract also may be useful. A series of two or sometimes

three small transverse incisions in a “stepladder” fashion is preferred to a long oblique incision in the neck, which is cosmetically undesirable .

Cystic Hygroma

Etiology and Pathology

Cystic hygroma (lymphangioma) occurs as a result of sequestration or obstruction of developing lymph vessels in approximately 1 in 12,000 births. Although the lesion can occur

anywhere, the most common sites are in the posterior triangle of the neck, axilla, groin, and mediastinum. The cysts are lined by endothelium and filled with lymph. Occasionally

unilocular cysts occur, but more often there are multiple cysts “infiltrating” the surrounding structures and distorting the local anatomy. A particularly troublesome variant of cystic

hygroma is that which involves the tongue, floor of the mouth, and structures deep in the neck . Adjacent connective tissue may show extensive lymphocytic infiltration.

The mass may be apparent at birth or may appear and enlarge rapidly in the early weeks or months of life as lymph accumulates; most present by age 2 years. Extension of the

lesion into the axilla or mediastinum occurs about 10 percent of the time and can be demonstrated preoperatively by chest x- ray, ultrasound (US) or computed tomographic (CT)

scan. Occasionally cystic hygromas contain nests of vascular tissue. These poorly supported vessels may bleed and produce rapid enlargement and discoloration of the hygroma.

The diagnosis of cystic hygroma by prenatal US, before 30 weeks' gestation, has detected a “hidden mortality” as well as a high incidence of associated anomalies, including

abnormal karyotypes and hydrops fetalis.

Infection within the cysts usually caused by Streptococcus or Staphylococcus may occur. In the neck this can cause rapid enlargement, which may result in airway compromise.

Rarely, it may be necessary to carry out percutaneous aspiration of an infected cyst to relieve respiratory distress.

Treatment

Surgical excision is the treatment of choice. Total removal may not be possible because of the extent of hygroma and its proximity to and intimate relationship with adjacent nerves,

muscles, and blood vessels. Radical ablative surgery is not indicated for this benign lesion. Conservative excision and unroofing of remaining cysts is advised, with repeated partial

excision of residual hygroma if necessary, preserving all adjacent crucial structures. Postoperative wound drainage is important and is best accomplished by closed-suction

technique. Despite this, fluid may accumulate beneath the surgically created flaps in the area from which the hygroma was excised, requiring multiple needle aspirations. Injection

of sclerosing agents (OK-432 or bleomycin) with favorable results has been reported, but widespread use of these agents has not been seen in this country.

Cervical Adenitis

Enlarged tender lymph nodes are usually the result of bacterial infection (Staphylococcus or Streptococcus). Treatment of the primary cause (e.g., otitis media or pharyngitis) with

antibiotics often is all that is necessary. However, when the involved nodes become fluctuant, incision and drainage are indicated, followed by appropriate wound care and dressing

changes. More chronic forms of lymphadenitis, including infections with tuberculosis and atypical mycobacteria, as well as cat-scratch fever, require further work- up to make the

diagnosis. In certain cases, extensive excision of the involved nodes will be necessary.

Torticollis

Fibrosis of the sternocleidomastoid muscle in infancy may produce shortening of the muscle and rotation of the head towards the opposite side. In two-thirds of cases, a mass may

be palpated in the affected muscle. Histologically, the lesion is characterized by the deposition of collagen and fibroblasts around atrophied muscle cells. For up to 80 percent of

patients, operation may not be needed, and physical therapy may be of some benefit. When necessary, surgical transection of the affected muscle is curative.

RESPIRATORY SYSTEM

Congenital Diaphragmatic Hernia (Bochdalek)

Pathology

During formation of the diaphragm, the pleural and coelomic cavities remain in continuity by means of the pleuroperitoneal canal. The posterolateral communication is the last to be

closed by the developing diaphragm. Failure of diaphragmatic development leaves a posterolateral defect known as Bochdalek hernia. This anomaly is encountered more

commonly on the left.

Incomplete development of the posterior diaphragm allows the viscera to fill the chest cavity. The abdominal cavity is small and undeveloped and remains scaphoid after birth. Both

lungs are hypoplastic, with decreased bronchial and pulmonary artery branching; lung weight, lung volume, and DNA content are decreased, all more severely evident on the

ipsilateral side. On rare occasions lung development is less adversely affected, signaling a greater chance of survival of the infant.

Prenatal US is successful in making the diagnosis of congenital diaphragmatic hernia (CDH) in the unborn child as early as 15 weeks' gestation. US findings include herniated

abdominal viscera, abnormal anatomy of the upper abdomen, and mediastinal shift away from the herniated viscera. Herniation appears to be a dynamic process in which the

viscera move in and out of the chest in some fetuses.

Prenatal criteria for a high-risk fetus include polyhydramnios, early diagnosis, a dilated stomach in the chest, and low lung-thorax ratio. Amniocentesis with karyotypes may show

chromosomal defects, especially trisomy 18 and 21. Associated anomalies, once thought to be uncommon, are identified in 40 percent of these infants, most often of the heart,

brain, genitourinary system, craniofacial structures, or limbs. Prenatal repair of CDH has had some success, and recent work has suggested that prenatal obstruction of the trachea

may exert a salutary effect on lung growth.

Following delivery, the bowel fills with air, and the mobile mediastinum shifts to the opposite side of the chest, compromising air exchange in the contralateral lung. Respiratory

failure occurs as a combination of the effect of hypoplasia of the lungs, persistence of fetal circulation as a result of pulmonary hypertension, and the mechanical compression of

the lungs from the herniated viscera. Chest x-ray is diagnostic .

Treatment

Many infants are symptomatic at birth due to hypoxia, hypercarbia, and metabolic acidosis, and prompt cardiorespiratory stabilization is mandatory. The goal of preoperative therapy

is to reverse the persistent pulmonary hypertension that results in right-to-left shunting across the open foramen ovale and the ductus arteriosus. Improvement in the infant's status

is apparent by improved oxygenation and ventilation. Immediate surgical repair is no longer performed. Instead the infant is stabilized by mechanical ventilation with 100% oxygen.

Hyperventilation is no longer widely practiced and the infants are often ventilated by high-frequency oscillation to avoid the pulmonary ravages of high inflating pressures. The goal

of preoperative therapy is to prevent or reverse pulmonary hypertension and metabolic acidosis and provide adequate oxygen delivery. Levels of hypercarbia once considered

unthinkable are tolerated. Newer techniques, such as intratracheal pulmonary ventilation and liquid ventilation, may offer some improved survival. The use of nitric oxide has been

disappointing in correcting the pulmonary hypertension associated with CDH.

Infants with CDH who fail to respond, and remain severely hypoxic despite optimal care are candidates for treatment of their respiratory failure by extracorporeal membrane

oxygenation (ECMO). Venovenous or venoarterial bypass is used. Venovenous bypass is established with a single cannula through the internal jugular vein, with blood removed

from and infused into the right atrium by separate ports. Venoarterial bypass is used preferentially by some centers because it provides the cardiac support that is often needed.

The right atrium is cannulated by means of the internal jugular vein and the aortic arch through the right common carotid artery . As much of the cardiac output is shunted

through the membrane oxygenator as needed to provide oxygenated blood to the infant and remove carbon dioxide. The infant is maintained on bypass until the pulmonary

hypertension is reversed and lung function, as measured by compliance, is improved. This is usually seen within 7 to 10 days but in some infants may take up to 3 weeks to occur.

Newborns who do not demonstrate significant improvement over this time have pulmonary hypoplasia that will not benefit from further extracorporeal life support.

The timing of diaphragm repair is controversial. Some surgeons perform early repair on bypass; others wait until the infant's lungs are fully recovered, repair the diaphragm and

discontinue bypass within hours of surgery. Still others repair the diaphragm only after the infant is off bypass.

Operative repair of the diaphragmatic hernia is best accomplished by an abdominal approach. Through a subcostal incision the abdominal viscera are withdrawn from the chest,

exposing the defect in the diaphragm. The anterior margin is often apparent, while the posterior muscular rim is attenuated. Most infants who need ECMO support prior to hernia

repair have large defects, often lacking the medial and posterior margins. Prior to the availability of ECMO therapy, most of these infants died.

If the infant is heparinized on bypass, minimal dissection of the muscular margins is performed. Electrocautery is used liberally to minimize postoperative bleeding. About

three-fourths of infants repaired on bypass require prosthetic material to patch the defect, suturing it to the diaphragm remnant or around ribs or costal cartilages for the large

defects. If there is adequate muscle for closure, a single layer of nonabsorbable horizontal mattress suture is used to close the defect. Just before the repair is complete, a chest

tube is positioned in the thoracic cavity and connected to 4 to 5 cmH 2O of suction.

Anatomic closure of the abdominal wall may be impossible after reduction of the viscera. Skin flaps are elevated and closed, creating a ventral hernia that may be closed using a

Goretex patch. Rarely, a Silastic “silo” must be placed because the skin cannot be approximated.

If the diaphragm has been repaired on ECMO, weaning and decannulation are accomplished as soon as possible. All infants are ventilated postoperatively to maintain postductal

arterial oxygenation of 80 to 100 torr. Very slow weaning from the ventilator is necessary to avoid recurrent pulmonary hypertension. Oscillation ventilation may be switched to

conventional ventilation as part of the process of weaning.

Currently there are no absolute criteria that successfully exclude the use of ECMO for these infants. Severe hypoxia or hypercarbia does not select infants who uniformly are

nonsurvivors. At present, over 60 percent of infants with congenital diaphragmatic hernia who are supported by ECMO can be expected to survive.

Congenital Lobar Emphysema

Congenital lobar emphysema (CLE) is a rare condition manifested during the first few months of life as a progressive hyperexpansion of one or more lobes of the lung. It can be

life-threatening in the newborn period but in the older infant causes less respiratory distress. Air entering during inspiration is trapped in the lobe; on expiration, the lobe cannot

deflate and progressively overexpands, causing atelectasis of the adjacent lobe or lobes. This hyperexpansion eventually shifts the mediastinum to the opposite side and

compromises the other lung. CLE usually occurs in the upper lobes of the lung (left greater than right), followed next in frequency by the right middle lobe, but it also can occur in

the lower lobes. It is caused by intrinsic bronchial obstruction from poor bronchial cartilage development or extrinsic compression. Approximately 14 percent of children with this

condition have cardiac defects, with an enlarged left atrium or a major vessel causing compression of the ipsilateral bronchus.

Symptoms range from mild respiratory distress to full-fledged respiratory failure with tachypnea, dyspnea, cough, and late cyanosis. These symptoms may be stationary or they may

progress rapidly. Diagnosis is made by chest x-ray which shows a hyperlucent affected lobe with adjacent lobar compression and atelectasis with varying degrees of shift of the

mediastinum to the opposite side and compression of the contralateral lung . If definitive diagnosis is unclear by chest x-ray, CT scan may be helpful. Unless foreign body

or mucous plugging is suspected as a cause of hyperinflation, bronchoscopy is not advisable because it can produce more air trapping and cause life-threatening respiratory

distress in a stable infant. Treatment is resection of the affected lobe, which may need to be done in urgent circumstances. The prognosis is excellent.

Congenital Cystic Adenomatoid Malformation

The clinical presentation of this lesion can be quite variable and lead to errors in diagnosis. The malformation consists of cystic proliferation of the terminal airway, producing cysts

lined by mucus-producing respiratory epithelium, and elastic tissue in the cyst walls without cartilage formation. There may be a single cyst with a wall of connective tissue

containing smooth muscle. Cysts may be large and multiple (type I), smaller and more numerous (type II), or resemble fetal lung without macroscopic cysts (type III). Most frequently

located in the left lower lobe, this lesion can occur in any lobe and may occur in both lungs simultaneously. In the left lower lobe, type I may be confused at birth with a congenital

diaphragmatic hernia. Clinical symptoms may range from none at all to severe respiratory failure. The cyst(s), whether single or multiple, can produce air trapping and thus be

confused with congenital lobar emphysema. They also can be involved with repeated infections and produce fever and cough in older infants and children, and be confused with

pulmonary sequestration or pneumatoceles.

The diagnosis often can be made by chest x-ray. In certain cases, US or CT scan may be definitive. US evaluation of the fetus may suggest the diagnosis prenatally, and in the

newborn US may be useful, especially to distinguish between adenomatous malformation and congenital diaphragmatic hernia. In older children who present with repeated

infections, it may be wise to rule out sequestration by Doppler US or aortography. Resection is curative and may need to be performed urgently in the infant with severe respiratory

distress. Lobectomy is usually required and the children do well following this procedure.

Pulmonary Sequestration

Pulmonary sequestration is uncommon and consists of a mass of lung tissue, usually in the left lower chest, occurring without the usual connections to the pulmonary artery or

tracheobronchial tree. There are two kinds of sequestration. Extralobar sequestration is usually a small area of nonaerated lung separated from the main lung mass, with a systemic

blood supply, located immediately above the left diaphragm. It is commonly found in cases of CDH. Intralobar sequestration more commonly occurs within the parenchyma of the

left lower lobe but can occur on the right. There is no major connection to the tracheobronchial tree, but a secondary connection may be established, perhaps through infection or

via adjacent intrapulmonary shunts. The blood supply is systemic from the aorta, often multiple, and frequently originates below the diaphragm . Venous drainage of both

types can be systemic or pulmonary. The cause of sequestration is unknown but most probably involves an abnormal budding of the developing lung that picks up a systemic blood

supply and never becomes connected with the bronchus or pulmonary vessels.

Extralobar sequestration is asymptomatic and is usually discovered incidentally on chest x-ray. If the diagnosis can be confirmed, e.g. by CT scan, resection is not necessary.

Diagnosis of intralobar sequestration, on the other hand, is usually made after repeated infections manifested by cough, fever, and consolidation in the posterior basal segment of

the left lower lobe. Increasingly the diagnosis is being made in the early months of life by US, and color Doppler often can be helpful to delineate the systemic arterial supply. An

arteriogram may be helpful in the older child in whom US of the chest is difficult, to help delineate the origin of the systemic blood supply and make surgical excision safer. Removal

of the entire left lower lobe is usually necessary since the diagnosis often is made late after multiple infections. Occasionally the sequestered part of the lung can be removed

segmentally. Prognosis is excellent.

Bronchogenic Cyst

Bronchogenic cysts can occur anywhere along the respiratory tract from the neck out into the lung parenchyma. They can present at any age. Histologically, they are

hamartomatous and usually consist of a single cyst lined with respiratory epithelium and containing cartilage and smooth muscle. They are probably embryonic rests of foregut

origin that have been pinched off from the main portion of the developing tracheobronchial tree and are closely associated in causation with other foregut duplication cysts

associated with the esophagus. Bronchogenic cysts may be seen on prenatal US but are discovered most often postnatally incidentally on chest x-ray and may be completely

asymptomatic. They may, however, produce symptoms, depending on their anatomic location. In the paratracheal region of the neck they can produce airway compression and

respiratory distress. In the lung parenchyma, they may become infected and present with fever and cough. In addition they may cause obstruction of the bronchial lumen with distal

atelectasis and infection. Chest x-ray usually will show a dense mass, and CT scan  or magnetic resonance imaging (MRI) will delineate the precise anatomic location of

the lesion. Treatment is resection of the cyst. Resection may need to be undertaken in emergency circumstances for airway compression. The prognosis is excellent.

Bronchiectasis

Bronchiectasis is an abnormal dilatation of the bronchi and bronchioles associated with chronic suppurative disease of the airways. Usually the children have an underlying

congenital pulmonary anomaly, cystic fibrosis, or immunologic deficiency. Bronchiectasis also can result from infection secondary to a neglected bronchial foreign body. The

symptoms include a chronic cough, often productive of purulent secretions, recurrent pulmonary infection, and hemoptysis. The diagnosis is suggested by a chest x-ray that shows

increased bronchovascular markings in the affected lobe. Historically, a bronchogram was required to demonstrate the saccular or fusiform distortion of the peripheral bronchi.

Chest CT delineates these lesions of bronchiectasis with excellent resolution. The preferred treatment for bronchiectasis is medical, consisting of antibiotics, postural drainage, and

avoidance of inhaled pollutants. Lobectomy or segmental resection is indicated for localized disease that has not responded appropriately to medical therapy.

Foreign Bodies

Airway

Aspiration of foreign bodies most commonly occurs in the toddler age group. The material aspirated is often the ubiquitous peanut, but there is a plethora of small objects that

youngsters put into their mouths that can be aspirated. A solid foreign body often will cause air trapping, with hyperlucency of the affected lobe or lung seen especially on expiration. Oil from the peanut is very irritating and may cause pneumonia. Delay in diagnosis can lead to atelectasis and infection. The most common anatomic location for a

foreign body is the right main stem bronchus or the right lower lobe. The child usually will cough or choke during eating but may then become asymptomatic. Total respiratory

obstruction with tracheal foreign body may occur, but usually respiratory distress is mild if present at all. A unilateral wheeze is often heard on auscultation. This wheeze often leads

to an inappropriate diagnosis of “asthma” and may delay the correct diagnosis for some time. Chest x-ray will show a radiopaque foreign body, but in the case of nuts, seeds, or

plastic toy parts, the only clue may be nondeflation of the affected lobe on an expiratory film or fluoroscopy. Bronchoscopy confirms the diagnosis and allows removal of the foreign

body. This can be a very simple procedure or it may be extremely difficult, especially with a smooth foreign body that cannot be grasped easily or one that has been retained for

some time. Bronchiectasis may be seen as an extremely late phenomenon after repeated infections of the poorly aerated lung and may require partial or total resection of the

affected lobe.

Esophagus

The most common foreign body in the esophagus is a coin. Again, toddlers are most commonly affected. The coin is retained in the esophagus at one of three locations: the

cricopharyngeus, the area of the aortic arch, or the gastroesophageal junction, all areas of normal anatomic narrowing. Symptoms are variable depending on the anatomic position

of the foreign body and the degree of obstruction, but occasionally include respiratory distress from compression of the trachea or inability to swallow saliva and drooling. Many

children are totally asymptomatic. The chest x-ray is diagnostic in the case of a coin. A contrast swallow may be required for nonradiopaque foreign bodies. Coins lodged within the

upper esophagus for less than 24 hours usually can be removed safely by an experienced physician in the emergency room. For all other situations, the treatment is by

esophagoscopy, rigid or flexible, and removal of the foreign body. In the case of sharp foreign bodies such as open safety pins, extreme care is required on extraction to avoid

injury of the esophagus itself. Diligent follow-up is required after removal of foreign bodies such as batteries, which can cause strictures, and occasionally, a foreign body calls

attention to a pre-existing stricture.

ESOPHAGUS

Esophageal Atresia and Tracheoesophageal Fistula

Perhaps no pediatric surgical condition has had as gratifying progress as the treatment of esophageal atresia and tracheoesophageal fistula. In the early decades of the twentieth

century, all babies born with this anomaly died. In 1939 Ladd and Leven achieved the first success with a complicated management plan that involved gastrostomy and fistula

ligation, followed by esophageal reconstruction with a skin tube. Over 50 years ago, Cameron Haight in Ann Arbor, Michigan, performed the first successful primary anastomosis for

esophageal atresia. This landmark achievement has been followed by steady improvement in survival for babies born with this condition. Currently most infants survive unless an

associated major anomaly supervenes. This progress has resulted not only from refinements in surgical technique, but also from advances in nutrition, respiratory care, antibiotics,

anesthesia, cardiology, genetics, and imaging technology.

Etiology and Pathology

The cause of this malformation is uncertain; however, it almost certainly relates to the common embryologic origin of the esophagus and trachea. Normally they divide into separate

tubes by 34 to 36 days' gestation, at which time the submucosal and muscular layers of both esophagus and trachea are apparent. When this separation is incomplete, a wide

spectrum of malformations may result. The most common esophageal malformation (85 percent) occurs as a blind-ending upper esophageal segment. The lower portion of the

esophagus connects to the trachea (Gross-Vogt type C) . The lower sophageal fistula usually joins the trachea at or just above the tracheal bifurcation, admitting

inspired air into the stomach and, in a retrograde fashion, gastric juice into the lungs.

Associated congenital anomalies are common and are the most significant factor influencing survival. Frequently esophageal atresia occurs as part of a collection of defects known

by the acronym VATER or VACTERRL ( vertebral, anorectal, cardiac, tracheoesophageal, renal, radial, limb). In nearly 20 percent of the infants born with esophageal atresia, some

variant of congenital heart disease occurs.

Clinical Manifestations

The earliest and most obvious clinical sign of esophageal atresia is regurgitation or drooling. Feedings are followed by choking or coughing, indicating aspiration. Abdominal

distention is a prominent feature, occurring when inspired air is transmitted through the fistula into the stomach. This sign differentiates “pure” esophageal atresia, in which no air

can pass into the gastrointestinal tract, and the abdomen is therefore scaphoid.

Regurgitated gastric juice passes through the fistula and into the trachea and lungs, leading to chemical pneumonia. The pulmonary problems are compounded by atelectasis,

which derives from diaphragmatic elevation secondary to gastric distention. The diagnosis may not be confirmed at the initial newborn examination by a physician, unless an

attempt is made to pass a tube into the stomach. Nurses who are feeding the baby and observing behavioral patterns such as the accumulation of mucus or saliva often make the

early diagnosis. In recent years, the diagnosis has been made prenatally with US examination. Polyhydramnios arouses suspicion, and failure to visualize a fetal stomach with US is

suggestive of the diagnosis of esophageal atresia.

For many surgeons, the demonstration of a tube coiled in an air-filled upper pouch on a plain film is adequate to diagnose esophageal atresia. For others, a contrast x-ray study is

required to confirm the diagnosis. Contrast medium instilled into the pouch outlines the blind upper esophagus . It also may document the existence of an upper pouch

fistula. Tracheal air enters the stomach via the fistula and establishes the presence of a tracheoesophageal communication on the x-ray. The condition of the lungs and the

existence of pneumonia or atelectasis are also essential information. Examination of the heart and great vessels with echocardiography is important to exclude cardiac defects and

verify the location of the aortic arch. In a stable infant, bronchoscopy at the time of repair allows localization of the level of the fistula, exclusion of upper pouch fistulas, and

identification of a laryngeotracheoesophageal cleft.

Treatment

With the diagnosis secure, the following measures should be instituted immediately: (1) infant warmer; (2) 30-degree head-up position; (3) route for I.V. therapy; (4) antibiotic

treatment (even if pneumonia is not yet clinically manifest); and (5) sump catheter suction in the upper pouch. It has become apparent that the major determinant of poor survival is

the presence of other severe anomalies; low birth weight and pneumonia are seldom risk factors for death. The optimal management strategy has evolved and is based on the

physiologic status of the infant. If the infant is stable, a primary repair is undertaken. If unstable, the repair is delayed until the problems are resolved and the infant can safely

undergo a major operation.

Primary Surgical Correction

The operative technique for primary repair is depicted . The keys are careful division of the fistula with closure of the tracheal opening and adequate mobilization of the

upper esophagus to permit an anastomosis without tension. The operation for primary repair of esophageal atresia and tracheoesophageal fistula has changed little since its

description by Cameron Haight, although most surgeons now perform a single-layer anastomosis rather than the original two-layer. The transpleural approach may be easier, but

the retropleural approach offers advantages. Exposure with this method is perfectly adequate, and protection of the lung by maintaining its pleural envelope has a salutary

postoperative effect. More important, an anastomotic leak will not communicate with the pleural cavity. A leak can be drained directly from the mediastinum posteriorly with

decreased morbidity. Although once routine, gastrostomy is rarely performed in the stable group of infants having primary repair.

Care must be taken when mobilizing the distal esophagus to avoid devascularization, since the blood supply is segmental from the aorta. Most of the esophageal length is obtained

from mobilizing the upper pouch, since the blood supply travels via the submucosa from above. Livaditis showed that incising the muscle of the upper pouch circumferentially

produced remarkable lengthening without compromising blood supply. This approach is useful if the distance between the two pouches precludes anastomosis without producing

undue tension.

Delayed or Staged Repair

For infants with serious coexisting anomalies or extreme prematurity, survival is limited. For these infants, a gastrostomy is placed and repair delayed. Nutritional support, coupled

with suction of the upper pouch and gastrostomy drainage, makes it possible to maintain infants with esophageal atresia and tracheoesophageal fistula indefinitely. Growth and

weight gain are achieved, pulmonary status is cleared, and the congenital anomalies are studied and corrected. Some infants, particularly premature ones with noncompliant lungs,

will not stabilize and require urgent division of the fistula. Anastomosis of the esophagus is accomplished at a later date.

Surgical correction of esophageal atresia with tracheoesophageal fistula leads to a satisfactory outcome with nearly normal esophageal function in most patients. Overall survival

rates of greater than 90 percent have been achieved in patients classified as stable. Unstable infants have an increased mortality (40 to 60 percent survival) because of potentially

fatal associated cardiac and chromosomal anomalies. However, the use of the staged procedure also has increased the survival in these high-risk infants.

Postoperative Course and Complications

The infant is maintained on parenteral nutrition for several days after repair. The chest tube is assessed daily for the presence of saliva indicating a leak. Many surgeons obtain a

contrast swallow 1 week after repair to assess the caliber of the anastomosis and to look for a leak. If there is no leak, the infant is begun on feedings. A leak at the anastomosis

usually heals without intervention, particularly if the pleural envelope has been maintained and drainage accomplished from the mediastinum via the retropleural route. Improved

management of infection, nutrition, and respiratory support in infants has contributed to success in handling anastomotic leaks.

Strictures are not infrequent (10 to 20 percent), particularly if a leak has occurred. A stricture may become apparent at any time, from the early postoperative period to months or

years later. It may present as choking, gagging, or failure to thrive, but often becomes clinically apparent with the transition to eating solid food. A contrast swallow or

esophagoscopy is confirmatory, and simple dilatation is usually corrective. Occasionally, repeated dilatations are required.

“Recurrent” tracheoesophageal fistula may represent a missed upper pouch fistula or a true recurrence. The mediastinal infection seen with an anastomotic disruption may cause

recurrence of the tracheoesophageal fistula. This complication may be difficult to identify and requires another operation to divide the tracheoesophageal fistula.

It has become apparent that even after repair, esophageal motility and the anatomy of the gastroesophageal junction are altered, potentially leading to gastroesophageal reflux.

The clinical manifestations of this reflux are similar to those seen in other infants with primary gastroesophageal reflux. An antireflux procedure, such as a Nissen fundoplication, is

used to prevent further reflux, but the child may have feeding problems after antireflux surgery as a result of the innate dysmotility of the distal esophagus.

Isolated Esophageal Atresia

Among those infants born with esophageal anomalies, 8 percent have isolated esophageal atresia. Characteristically, infants with isolated esophageal atresia present with a

scaphoid abdomen, since the gastrointestinal tract is devoid of air. The x-ray finding of a blind upper pouch and the absence of air below the diaphragm is pathognomonic of

isolated esophageal atresia without fistula.

The ideal surgical management is based on conservation of the native esophagus. Many surgeons perform a gastrostomy for feeding and wait 6 to 10 weeks for the upper pouch to

dilate and elongate. On imaging studies, if it looks as though the two ends can be approximated, primary anastomosis is attempted. If the ends do not reach, however,

esophagostomy with the upper esophageal pouch brought to the skin of the left side of the neck allows drainage of saliva and prevents aspiration. Esophageal replacement with a

colon segment or reversed gastric tube is then recommended at 1 year of age.

Isolated (H-Type) Tracheoesophageal Fistula

In rare instances (4 percent), an isolated congenital fistula connecting the trachea to the esophagus may exist. In this anomaly, both the trachea and the esophagus are otherwise

normal, with no narrowing or obstruction. Infants with this condition seem to swallow normally. The clinical features are subtle; weeks or months may elapse before a correct

diagnosis is made. The presence of an H-type tracheoesophageal fistula is suggested by the following triad of symptoms: (1) choking when feeding, (2) gaseous distention of the

bowel, and (3) recurrent aspiration pneumonia. Diagnosis usually can be confirmed by cine contrast x-ray studies or by bronchoesophagoscopy. Definitive treatment consists of

dividing the fistula. Surgical closure of the esophagus and trachea must be meticulous, and encroachment on the lumen of the trachea must be avoided. The fistula is usually

accessible to surgical repair through an incision just above the clavicle.

Laryngotracheoesophageal Cleft

Another variant of the failure of the trachea and esophagus to separate results in a communication that may be confined to the larynx or extend over the entire length of the trachea

to the carina. The diagnosis is suggested by recurrent aspiration and is confirmed with bronchoscopy. The cleft is frequently present in association with esophageal atresia. The

early management consists of tracheostomy, gastrostomy, and antireflux operation. At a later time the cleft is closed. Although once always fatal, most of these defects can now be

repaired successfully.

Corrosive Injury of the Esophagus

The toddler age group is the most vulnerable to injury by ingestion of corrosive substances. Curiosity may lead a child to ingest crystals or an unknown liquid especially if it is placed

in a drinking container. Since children gulp rather than taste, a single mouthful can cause severe injury. Both strong alkalis and strong acids produce injury by liquefaction or

coagulation necrosis, and since all corrosive agents are extremely hygroscopic, the caustic will cling to the esophageal epithelium. Injury and therefore subsequent strictures occur

at the anatomic narrowed areas of the esophagus, cricopharyngeus, midesophagus, and gastroesophageal junction. A child who has swallowed an injurious substance may be

symptom-free but usually will be drooling and unable to swallow saliva. Most corrosives are swallowed accidentally by children and the volume ingested is limited to a single swallow

because of the noxious taste and pain. Distal injuries to the stomach are therefore less common than in adults. However, the child must be observed carefully for signs of peritoneal

irritation.

There is no effective immediate antidote. Diagnosis is by careful physical examination of the mouth and endoscopy with a flexible or a rigid esophagoscope. It is important to

endoscope only to the first level of the burn in order to avoid perforation. Early barium swallow may delineate the extent of the mucosal injury, and it is important to realize that the

esophagus may be burned without evidence of a mouth injury. Steroids have not been shown to alter the development of stricture or modify the extent of injury and therefore are no

longer used, but antibiotics are continued for 3 weeks after injury. Circumferential esophageal injuries with necrosis will almost certainly stricture and therefore will be dealt with most

safely by a gastrostomy and a string inserted either through the esophagus immediately or at a repeat esophagoscopy 3 weeks later. Dilatation is attempted after a minimum of 3

weeks to avoid perforation and is restricted to established strictures. For more severe injuries, retrograde dilatations are safest, using graduated dilators brought through the

gastrostomy and advanced into the esophagus via the transesophageal string. For less severe injuries, dilatation may be attempted in antegrade fashion by either graded bougies

or balloons. Perforation during dilation is extremely rare in experienced hands. Treatment of an iatrogenic perforation is controversial and ranges from nonoperative treatment with

closed chest drainage to immediate operative closure. Abandonment of the esophagus is usually not necessary if recognition is prompt and treatment timely. Dilatations are

continued as often as necessary, with the goal of keeping the child out of the hospital and eating a normal diet until the stricture is resolved or it is clear that esophageal substitution

is required. Strictures have resolved as late as 6 months to a year after injury. Every attempt should be made to preserve the native esophagus.

Esophageal Substitution

Esophageal substitution is required less frequently than heretofore. The incidence of caustic strictures has been markedly diminished by the introduction of child-proof containers,

and there have been successes with end-to-end anastomosis after a period of growth in infants with isolated esophageal atresia or wide gap esophageal atresia with fistula.

However, these conditions are still the major indications for esophageal substitution in children. The options for esophageal substitution are the colon (right colon or transverse/left

colon), reversed gastric tube, gastric pull-up or pedicled or free, grafts of the jejunum. The right colon is based on a pedicle of the midcolic artery, the left colon, on a pedicle of the

midcolic or left colic artery . Gastric tubes are made from the greater curvature of the stomach based on the pedicle of the left gastroepiploic artery. When the whole

stomach is used, the vascularity is supplied by the right gastric artery. The route of the neoesophagus to the neck is at the surgeon's discretion. The substernal and left

transthoracic route are still the most popular. Bringing the substitute through the posterior mediastinum, either following blunt esophagectomy in the case of caustic stricture or by

creating a new tunnel in the case of esophageal atresia, avoids a thoracotomy and ensures the straightest path from neck to abdomen. Long-term follow-up has shown that all

methods of substitution can support normal growth and development, and the children enjoy reasonably normal eating habits. Because of the potential for late complications such

as ulceration and stricture, follow-up into adulthood is mandatory, but complications appear to diminish with time.

Gastroesophageal Reflux

Gastroesophageal reflux (GER) occurs to some degree in all children. GER is considered to be pathologic when it interferes with nutrition, causing failure to thrive; damages the

esophagus, causing bleeding or stricture formation; or it leads to pulmonary problems such as reactive airway disease, aspiration pneumonia or apnea. Failure to thrive and

pulmonary problems are particularly common in infants with GER, whereas strictures and esophagitis are more common in older children and adolescents. The majority of children

with severe GER that is unresponsive to medical therapy are neurologically impaired.

Clinical Manifestations

A history of repeated episodes of vomiting in an infant is the clearest indication of GER after obvious anatomic obstruction at or beyond the pylorus has been excluded. When the

vomiting is associated with failure of normal development or chronic respiratory symptoms, the likelihood of pernicious GER is increased.

A child suspected of having GER is evaluated with a barium swallow to rule out an anatomic obstruction in the stomach or duodenum and a 24-h pH probe study to determine the

severity of the reflux. The radioisotope “milk scan” is used to evaluate gastric emptying but is not obtained routinely if the upper gastrointestinal study shows normal gastric

emptying. Endoscopy with biopsies to prove esophagitis is utilized only in selected patients.

Treatment

Most patients with GER are treated initially by conservative means. In the infant, propping and thickening the formula with rice cereal are generally recommended, although some

authors prefer a prone, head-up position. In the infant unresponsive to position and formula changes and the older child with severe GER, medical therapy is based on gastric acid

reduction with an H2 blocking agent (i.e. ranitidine) and a prokinetic agent (i.e. cisapride). Surgery is indicated if medical therapy has failed to prevent complications of GER or there

is an anatomic abnormality such as a large hiatal hernia or esophageal stricture. In children less than 1 year old or those unable to swallow because of neuromotor problems, a

gastrostomy is performed routinely with the antireflux procedure.

Antireflux surgery is either by a complete (i.e. Nissen) or partial (i.e. Thal) fundic wrap around the distal esophagus. These procedures can be done safely in children

laparoscopically. Postoperative complications of gagging, pulmonary problems and wrap breakdown with recurrent GER are quite high in children with neurologic impairment.

GASTROINTESTINAL TRACT

Pyloric Stenosis

Clinical Manifestations

Hypertrophic pyloric stenosis occurs in approximately 1 in 300 live births and is the most common surgical cause of vomiting in infancy. The typical infant is 4 to 6 weeks of age,

male, and the first born child. Nonbilious vomiting, becoming increasingly projectile, occurs over several days to weeks. Eventually the infant will develop a nearly complete

obstruction by the second to fourth week of life, and will not be able to hold down even clear liquids. This invariably proceeds to severe dehydration if not treated. These infants

develop a metabolic alkalosis with severe depletion of potassium and chloride ions. The serum pH level is high, whereas the urine pH level is high initially but eventually drops as

the severe potassium deficit leaves only hydrogen ions to exchange with sodium ions in the distal tubule of the kidney.

The diagnosis of pyloric stenosis usually can be made on physical examination by palpation of the typical “olive” in the right upper quadrant and the presence of visible gastric

waves on the abdomen. When the olive cannot be palpated, US in experienced hands will diagnose the condition accurately in 95 percent of patients.

Treatment

Pyloric stenosis is not a surgical emergency. Fluid resuscitation with correction of electrolyte abnormalities and metabolic alkalosis is essential before induction of general

anesthesia for operation. For most infants, I.V. fluid containing 5% dextrose and 0.45% saline with added potassium of 2 to 4meq/kg over 24h at a rate of approximately 150 to

175mL/kg for 24h will correct the underlying deficit. After this resuscitation, a Fredet-Ramstedt pyloromyotomy is performed. Postoperatively, I.V. fluids are continued

for several hours after which small frequent feedings of dilute formula or breast milk are offered and are gradually increased to full strength and full volume over the next 24 to 48h.

Most infants can be discharged home within 48h following surgery.

Intestinal Obstruction in the Newborn

Bilious (green) vomiting is the most common presenting symptom in a newborn with intestinal obstruction. If the abdomen is not distended and the abdominal plain films show

complete obstruction with no distal air, then the obstruction is most likely at the level of the duodenum or the pylorus. If there is incomplete obstruction with some gas more distally

in the bowel, then an upper gastrointestinal series is mandated to diagnose malrotation with possible midgut volvulus. If, however, the abdomen is distended, the obstruction is most

likely more distal. The physical examination will determine whether or not the anus is patent. Calcifications on the abdominal plain film may indicate meconium peritonitis;

pneumatosis and/or free abdominal air indicates necrotizing enterocolitis (NEC) with or without intestinal perforation. Otherwise a contrast enema will show whether there is a

microcolon indicative of jejunal-ileal atresia or meconium. If a microcolon is not present, then the diagnoses of Hirschsprung's disease, small left colon syndrome, and meconium

plug will be entertained.

Duodenal Malformations

Duodenal obstruction may be complete as in duodenal atresia or partial as in duodenal web or stenosis, annular pancreas, and malrotation of the midgut. A prenatal US may show

duodenal obstruction by demonstrating fluid filled cystic structures in the upper abdomen. Associated polyhydramnios is common and presents in the third trimester. In 85 percent of

infants with duodenal obstruction, the entry of the bile duct is proximal to the level of obstruction, such that vomiting is bilious. Abdominal distention is not present because of the

proximal level of obstruction. In those infants with obstruction proximal to the bile duct entry, the vomiting is nonbilious. Approximately one third of newborns with duodenal atresia

have associated Down's syndrome (trisomy 21). The “double bubble” seen on the air contrast upper gastrointestinal series is characteristic of duodenal atresia, with small amounts

of air seen distally if obstruction is incomplete .

A naso- or orogastric tube is passed to decompress the stomach and duodenum and the infant is given I.V. fluids to maintain adequate urine output. The infant should be evaluated

thoroughly for other associated anomalies, especially cardiac, since surgery is non-emergent. However, surgery should not be delayed if malrotation is the cause of duodenal

obstruction or if malrotation is present with intrinsic duodenal obstruction.

Once the work-up is complete and the infant is stable, he or she is taken to the operating room and the abdomen entered through a transverse right upper quadrant supraumbilical

incision under general endotracheal anesthesia. Associated anomalies found at the time of the operation include annular pancreas, malrotation, anterior portal vein, second distal

web, and biliary atresia. Most surgeons will perform a duodenoduodenostomy to correct the anomaly using either a standard side-to-side or proximal transverse-to-distal longitudinal

(diamond shaped) anastomosis with appropriate suture. An annular pancreas is never divided. Webs can be excised through a vertical duodenal incision, the mucosal oversewn,

and the duodenotomy closed horizontally. Gastrostomy tubes are not placed routinely. Recently reported survival rates exceed 90 percent. Late complications from repair of

duodenal atresia occur in approximately 12 to 15 percent of patients and include megaduodenum, intestinal motility disorders, duodenogastric reflux, gastritis, peptic ulcer,

gastroesophageal reflux, choledochal cyst, and cholelithiasis with cholecystitis.

Intestinal Atresia

Fetal mesenteric vascular accidents are likely to be the cause of most cases of intestinal atresia, based on a large amount of experimental and clinical data. The incidence of

intestinal atresia has been estimated to be between 1 in 2000 to 1 in 5000 live births, with equal representation of the sexes. Clinically the infants with jejunal or ileal atresia present

with bilious vomiting and progressive abdominal distention. The degree to which the abdomen becomes distended and the number of obstructed loops on upright abdominal films

correlates roughly with the level of the obstruction .

In 12 percent of patients, calcification can be observed on the plain abdominal films diagnosing prenatal perforation and meconium peritonitis. Work-up of the newborn with

suspected jejunal-ileal atresia includes a barium enema. The information from this procedure can distinguish small versus large intestinal distention, whether or not a microcolon is

present, the level of obstruction, and the position of the cecum.

Surgical correction of the small intestinal atresia is urgent. At laparotomy, one of several types of atresia will be encountered. In type I there is a mucosal atresia with intact

muscularis. In type 2 the atretric ends are connected by a fibrous band. In type 3A the two ends of the atresia are separated by a V-shaped defect in the mesentery. Type 3B is an

“apple- peal” deformity or “Christmas tree” deformity in which the bowel distal to atresia receives a retrograde blood supply from the ileal colic or right colic artery. In type 4 atresia,

there are multiple atresias with a “string of sausage” or “string of beads” appearance. Disparity in lumen size  between the proximal distended bowel and the small

diameter of collapsed bowel distal to the atresia has lead to a number of innovative techniques of anastomosis. These include 1) end-to-back technique, fish- mouthing the

antimesenteric border of the distal loop; 2) tapering of the proximal distended loop to correspond to the distal loop with end-to-end anastomosis; 3) Bishop-Koop end-to-side union

with exteriorization of the distal lumen, and rarely, 4) Mikulicz exteriorization or 5) end ileostomies with delayed anastomosis .

Malrotation and Midgut Volvulus

During fetal development, the midgut supplied by the superior mesenteric artery grows too rapidly to be accommodated in the abdominal cavity. Prolapse into the umbilical cord

occurs around the sixth week. Between the tenth and twelfth week, the midgut returns to the abdominal cavity, undergoing a 270 degree counterclockwise rotation around the

superior mesenteric artery. The duodenum rotates caudal to the artery, and its C- loop traces this path. The transverse and ascending colon demonstrate the path of rotation of the

cecum cephalad to the artery. The duodenum becomes fixed retroperitoneally in its third portion, emerging at the ligament of Treitz, and the cecum becomes fixed to the lateral

abdominal wall by peritoneal bands. The takeoff of the branches of the superior mesenteric artery elongates and becomes fixed along a line extending from its emergence from the

aorta to the cecum in the right lower quadrant. If rotation is incomplete, the cecum remains in the epigastrium, but the bands fixing the duodenum to the retroperitoneum and cecum

continue to form. This results in bands (Ladd's bands) extending from the cecum to the lateral abdominal wall and crossing the duodenum with the potential for obstruction. The

mesenteric takeoff remains confined to the epigastrium, resulting in a narrow pedicle suspending all the branches of the superior mesenteric artery and the entire midgut. A volvulus

may occur around the mesentery, obstructing the jejunum and also cutting off the blood supply to the midgut. Intestinal obstruction and the potential for total vascular compromise

of the midgut supervene unless the condition is corrected.

Midgut volvulus can occur at any age, though it is seen most often in the first few weeks of life. Bilious vomiting is usually the first sign of volvulus and all infants with bilious

vomiting must be evaluated rapidly to insure that they do not have intestinal malrotation with volvulus. Chronic obstructive symptoms from Ladd's bands across the duodenum may

manifest as intermittent vomiting, but a volvulus presents early with irritability and bile vomitus and later with manifestations of vascular compromise such as bloody stools and

eventually circulatory collapse. The index of suspicion for this condition must be high, since abdominal signs are minimal in the early stages. Advanced ischemia of the intestine

results in erythema and edema of the abdominal wall, shock and rapidly, death. Abdominal films show a paucity of gas throughout the intestine with a few scattered air-fluid levels.

The diagnosis of malrotation is best made by an upper gastrointestinal series that shows incomplete rotation with the duodenojejunal junction displaced to the right. The duodenum

may show a corkscrew effect diagnosing volvulus, or complete duodenal obstruction, with the small bowel loops entirely in the right side of the abdomen. Barium enema may show

a displaced cecum, but this sign is unreliable, especially in the small infant in whom the cecum is normally in a somewhat higher position than in the older child.

Early surgical intervention is mandatory if the ischemic process is to be avoided or reversed. Volvulus occurs clockwise and it is therefore untwisted counterclockwise. The bands

between the cecum and the abdominal wall and between the duodenum and terminal ileum are divided sharply to splay out the superior mesenteric artery and its branches. This

brings the straightened duodenum into the right lower quadrant and the cecum into the left lower quadrant. The appendix is removed to avoid diagnostic errors in later life . If the bands have been lysed completely no suturing of the cecum or duodenum is necessary. With advanced ischemia, reduction of the volvulus without the Ladd

procedure is accomplished, and a “second look” 24 hours to 36h later often will show vascular recovery. Frankly necrotic bowel can then be resected conservatively. With early

diagnosis and correction the prognosis is excellent. With delays in diagnosis, the infant may succumb or be condemned to the ravages of shortgut syndrome until intestinal

transplantation becomes routinely possible.

Meconium Ileus

Meconium ileus produces intestinal obstruction from impaction of meconium in the distal ileum. The ideology of this problem is cystic fibrosis. These infants have deficits of

pancreatic enzymes in the intestine producing viscous meconium. Bilious vomiting appears late, following progressive abdominal distention, failure to pass meconium, and

impressively dilated loops of small bowel on upright abdominal film without air fluid levels. Small bubbles of gas entrapped in the inspissated meconium in the terminal ileum may

produce a characteristic “ground glass” appearance. A contrast enema will demonstrate a microcolon and the terminal ileum filled with pellets of meconium . In patients

with prenatal intestinal perforation, intraperitoneal calcifications form, producing an eggshell pattern on plain abdominal x-ray. Patients with uncomplicated meconium-ileus, i.e.

patients without intestinal perforation or vascular compromise of the distended ileum, can be treated nonoperatively by a method originally described by Noblett.

Dilute Gastrografin is advanced through the colon under fluoroscopic control into the dilated portion of the ileum. Since Gastrografin acts partially by absorbing fluid from the bowel

wall into the intestinal lumen, maintaining adequate hydration of the infant during this maneuver is extremely important. The enema may be repeated at 12-h intervals over several

days until all the meconium is evacuated per rectum. If surgical intervention is required because of failure of Gastrografin enemas to relieve obstruction, operative irrigation with

dilute Gastrografin or acetylcysteine (Mucomyst) through a purse-string suture may be successful. Alternatively, resection of the distended terminal ileum is performed, the

meconium pellets are flushed from the distal small bowel by acetylcysteine, and ileostomies, a Bishop-Koop anastomosis, or an end-to-end anastomosis is performed.

Necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a disease of multifactorial origin that almost exclusively affects stressed premature infants. Common factors found in most infants with NEC include intestinal ischemia, bacterial colonization of the gut, and enteral feedings of synthetic formulas. Hypoalbuminemia may predispose neonates to NEC. Experimental evidence

suggests that both ischemia and reperfusion may lead to the intestinal damage seen in NEC. Clinically the first sign of NEC is formula intolerance, evident by vomiting or a large

residual volume of a previous feeding in the stomach at the time of the next feeding. Abdominal distention and hematochezia are the next signs of NEC and suggest ileus and

mucosal ischemia, respectively. Invasion of the ischemic mucosa by gas-forming organisms causes pneumatosis intestinalis, which is the pathognomonic radiographic finding in

NEC . Development of hepatoportal venous gas suggests a particularly severe form of NEC. Some children, despite appropriate medical therapy, will develop a

fulminant course with progressive peritonitis, acidosis, sepsis, disseminated intravascular coagulopathy, and death.

Treatment

In all infants suspected of having NEC, feedings are discontinued, a nasogastric tube is placed, and parenteral antibiotics are given. Free intraperitoneal air and signs of diffuse

peritonitis are obvious indications for operation. Children with significant acidosis (pH < 7.20) after volume resuscitation and those with hepatoportal venous gas who do not improve

promptly on medical therapy are also considered surgical candidates. In equivocal cases, tapping the peritoneal cavity may aid in the decision to operate if the fluid withdrawn

contains bacteria or intestinal contents. Resection of frankly gangrenous bowel should be carried out, and in the vast majority of cases, the intestinal ends are brought out as

stomas. When there is massive intestinal involvement, marginally viable bowel is retained and a “second-look” procedure is carried out in 24h. In the selected neonate weighing less

than 1500 grams, drainage of the peritoneal cavity under local anesthesia is an effective method of improving the desperately ill infant, with approximately one-third surviving

without additional operations.

Total parenteral nutrition is maintained for at least 2 weeks postoperatively, after which oral feedings of small volumes of dilute formula are gradually introduced. Strictures develop

in 20 percent of medically or surgically treated patients, and a contrast enema is mandatory before reestablishing intestinal continuity. If all other factors are favorable, the ileostomy

is closed when the child is between 2 and 2.5 kg. Despite the severity of the illness in this premature population, survival rates for NEC approach 80 percent in many series.

Intussusception

Intussusception is a common cause of intestinal obstruction in the infant. It is observed most often in infants between 8 and 12 months of age and is slightly more common in males.

The most common cause is hypertrophy of the Peyer's patches in the terminal ileum from an antecedent viral infection. The hypertrophied lymphatic patch becomes drawn into the

lumen of the terminal ileum and is moved progressively into the ascending and transverse colon. Polyps, malignant tumors, such as lymphoma, and Meckel's diverticulum may act

as lead points for intussusception; such intussusceptions are rarely reduced by air or contrast enema, and thus the lead point is identified when operative reduction of the

intussusception is performed.

Clinical Manifestations

Since intussusception is frequently preceded by a gastrointestinal viral illness, the onset may not be determined easily. Typically, the infant develops paroxysms of crampy

abdominal pain and intermittent vomiting. Between attacks the infant may act completely well, but as symptoms progress, increasing lethargy develops. Bloody mucus

(“currant-jelly” stool) may be passed per rectum. Ultimately, if reduction is not accomplished, gangrene of the intussusceptum occurs.

The pathognomonic physical finding is an elongated mass in the right upper quadrant or epigastrium with an absence of bowel in the right lower quadrant (Dance's sign). The mass

may be seen on plain abdominal x-ray but is more easily demonstrated on air or contrast enema.

Treatment

The air enema is the preferred method of diagnosis and nonoperative treatment of intussusception. Air is introduced with a manometer and pressure should not exceed 120 mmHg.

Peritonitis constitutes a contraindication to air enema. The air may push the intussusception before it and accomplish reduction. Free reflux into multiple small bowel loops and an

infant who abruptly becomes well are characteristic of successful reduction. Unless both these signs are observed, it cannot be assumed that the intussusception is reduced, and

preparations for exploration are made. Despite reports of successful reduction in more than 90 percent of children with intussusception using air enema, most centers are achieving

about 60 percent successful reduction with this technique.

If hydrostatic reduction is successful, the infant may be given oral fluids immediately. The incidence of recurrent intussusception is 5 percent whether the intussusception is reduced

by operation or by hydrostatic pressure. Failure to reduce the intussusception mandates surgery. Exploration is carried out through a right lower quadrant incision, delivering the

intussuscepted mass into the wound. Reduction usually can be accomplished by gentle distal pressure, milking the bowel out of the intussuscipiens, never pulling it out. The blood

supply to the appendix is often compromised, and appendectomy is performed. Resection of frankly gangrenous bowel is carried out without attempting reduction of the

intussusception. As a rule, primary ileocolic anastomosis can be performed after resection.

I.V. fluids are continued until peristalsis returns. If resection is necessary, prophylactic antibiotics are also administered for 72 h.

Appendicitis

Clinical Manifestations

Appendicitis in children may differ in presentation from the same disease in adults. The incidence of perforation rises dramatically as the age of the patient decreases so that

perforated appendicitis occurs in approximately 25 percent of adolescents but 80 percent of children less than 5 years old. The frequency of gastroenteritis and the poor localization

of pain in the young child both increase the risk of ascribing the pain to a viral etiology, delaying a visit to the doctor and once seen by the doctor, the low index of suspicion that the

problem is appendicitis further delays the correct diagnosis, increasing the risk of perforation.

Once the appendix has perforated, the symptoms may be most consistent with severe gastroenteritis with pain, vomiting and diarrhea, or the child may present with a pattern of

intestinal obstruction. An abdominal mass in the lower abdomen, in an ill-appearing child may well be an appendiceal abscess rather than a malignancy.

Sonography has been disappointing in assisting with the diagnosis of appendicitis. Contrast enema and abdominal CT with enteric contrast material are the best radiographic

studies to diagnose late appendicitis in the unclear case. In the male, right lower quadrant peritoneal tenderness and leukocytosis should prompt exploration regardless of other

signs and symptoms. In the female, ovarian or uterine pathology also must be considered. In girls over 10 years of age, laparoscopy is very helpful in making the correct diagnosis

of low abdominal pain and is almost always a successful method of treating that problem. Management of an appendiceal abscess “mass” by drainage percutaneously and I.V.

antibiotics has been advocated by some, but most pediatric surgeons prefer early operative drainage of the abscess and appendectomy.

Duplications, Meckel's Diverticulum, and Mesenteric Cysts

Duplications

Duplications can occur at any level in the gastrointestinal tract but are found most commonly in the ileum. They may be long and tubular, but usually are cystic masses lying within

the leaves of the mesentery and sharing a common wall with the intestine. Symptoms can include a palpable mass and/or frank intestinal obstruction. Torsion may produce

gangrene and perforation, and subtle or massive bleeding may occur. This bleeding comes from ulceration in the duplication or adjacent intestine if the duplication contains ectopic

gastric mucosa.

The ability to make a preoperative diagnosis of duplication usually depends on the presentation. Sonography and technetium pertechnetate scanning are the two most helpful

diagnostic tests. In the case of short duplications, resection of the cyst and adjacent intestine with end-to-end anastomosis can be performed in a straightforward fashion. If

resection of long duplications would compromise intestinal length, multiple enterotomies and mucosal stripping in the duplicated segment will allow the walls to collapse and become

adherent. An alternative method is to divide the common wall using the GIA stapler, forming a common lumen. This should not be done in duplications that contain ectopic gastric

mucosa. In the patient with a very long duplication or multiple duplications, intraoperative nuclear medicine scanning will ensure complete excision of the ectopic gastric mucosa.

Meckel's Diverticulum

A Meckel's diverticulum is a remnant of a portion of the embryonic omphalomesenteric (vitelline) duct. It is located on the antimesenteric border of the ileum, usually within 2 ft of the

ileocecal valve. It may be found incidentally at surgery or may present with inflammation masquerading as appendicitis. Similar to duplications, ectopic gastric mucosa may produce

ileal ulcerations that bleed and lead to the passage of maroon-colored stools. Diagnosis may be made by technetium pertechnetate scans when the patient presents with bleeding.

Treatment is surgical, and a wedge resection of the diverticulum with transverse closure of the ileum can be performed if the base is narrow. If wedge excision would compromise

the ileal lumen, sleeve excision and end-to-end ileoileostomy are performed.

Mesenteric Cysts

Mesenteric cysts are similar to duplications in their location within the mesentery. However, they do not contain any mucosa or muscular wall. Chylous cysts may result from

congenital lymphatic obstruction . Mesenteric cysts can cause intestinal obstruction or may present as an abdominal mass. The diagnosis may be made by US or

abdominal CT. At operation, surgical excision is preferred sometimes requiring resection of the adjacent intestine. Partial excision or marsupialization should be reserved for cysts

involving a large portion of the mesentery.

Hirschsprung's Disease

Hirschsprung's disease results from the absence of ganglion cells in the myenteric plexus of the intestine. Recent findings suggest that mutations in the RET protooncogene may be

responsible for many cases of Hirschsprung's disease. The precursors of the ganglion cells are neural crest cells that migrate into the intestine from cephalad to caudad. The

process is completed by the twelfth week of embryonic life, but the migration from midtransverse colon to anus takes 4 weeks. This increases the time period of vulnerability for

failure of migration and accounts for the fact that most cases of aganglionosis involve the rectum and rectosigmoid. Longer segments of absent ganglion cells also may occur, and

total colonic aganglionosis, although rare, is also seen.

Aganglionic colon does not permit normal peristalsis to occur. Functional obstruction therefore supervenes, and the infant may present with complete colon obstruction or with a

devastating enterocolitis. The presentation may, however, be much more subtle, with constipation and abdominal distention as the chief findings. Occasionally failure to thrive is the

initial sign.

Diagnosis

Infants with Hirschsprung's disease usually will fail to pass meconium in the first 24 h of life, although this history is often difficult to obtain. Barium enema may be unreliable in

diagnosing Hirschsprung's disease in the newborn infant because the colon is not dilated enough to show a transition zone. In older infants and children, barium enema will show

the size difference between the dilated ganglionic colon and the distal constricted aganglionic rectal segment. The barium enema in total colonic aganglionous usually shows a

markedly shortened colon.

Rectal biopsy makes the definitive diagnosis of Hirschsprung's disease. Suction rectal biopsy provides a small piece of mucosa and submucosa without the requirement for

anesthesia. Occasionally the suction biopsy is not diagnostic and a full-thickness biopsy is required. The histopathology of Hirschsprung's disease is the absence of ganglion cells

in the myenteric plexuses, increased staining of a cholinesterase stain and the presence of hypertrophied nerve bundles. Some surgeons have found the use of rectal manometry

helpful, particularly in older children, but it is not as accurate a diagnostic tool as is rectal biopsy.

Treatment

Treatment is surgical in all cases. Some pediatric surgeons prefer to create a colostomy in the newborn period and wait until the child weighs 10 kg before performing a definitive

pull-through operation. When a colostomy is done for Hirschsprung's disease, a frozen-section confirmation that ganglion cells are present at the colostomy site is mandatory. Some

surgeons advocate primary pull-through operations in newborn infants without colostomy. The intraabdominal dissection can be performed using the laparoscope, even in the

newborn. In the older infant and child who have been diagnosed belatedly, it is important to allow the distended hypertrophied colon to return to a normal size before performing a

pullthrough. This is usually accomplished by waiting 3 to 6 months after a colostomy is performed.

Three pull-through procedures are currently in use for treating Hirschsprung's disease. The first of these is the original Swenson procedure, in which the aganglionic rectum is

carefully dissected in the pelvis and removed down to the anus. The ganglionic colon is then anastomosed to the anus via a perineal approach . In the Duhamel

procedure , dissection outside the rectum is confined to the retrorectal space, and the ganglionic colon is anastomosed posteriorly just above the anus. The anterior

wall of the ganglionic colon and the posterior wall of the aganglionic rectum are anastomosed, using a stapling device. In Soave's operation, dissection is entirely within the rectum. The rectal mucosa is stripped from the muscular sleeve, and the ganglionic colon is brought through this sleeve and anastomosed to the anus. Complications with all

procedures include enterocolitis, constipation and anastomotic stricture, but long-term results with the three procedures are comparable and generally excellent in experienced

hands. These three procedures also can be adapted for total colonic aganglionosis; the ileum is used for the pull-through or anastomosed to the aganglionic segment of distal colon

and rectum to improve absorption.

Imperforate Anus

Imperforate anus occurs in approximately 1 in 5000 live births, affecting males and females almost equally. Failure of descent of the urorectal septum in embryonic life produces a

variety of anorectal and cloacal anomalies. The level to which this septum descends determines the separation of the urinary and hindgut systems. Broadly classified, the

imperforate anus is characterized as “high” or “low” depending on whether the rectum ends above the levator ani muscle complex or partially descends through this muscle. In high

imperforate anus in males the rectum usually ends as a fistula into the membranous urethra. In females, the high imperforate anus often is part of a cloacal anomaly.

The low lesions have a fistula to the perineum. In males this is seen in the median raphe of the scrotum or penis, and in females the most common perineal fistula ends at the

posterior fourchette. Since the rectum has descended through the levator complex in low lesions, only a perineal operation is required; this situation occurs in 40 percent of males

and 70 percent of females with imperforate anus. Such children will be expected to be continent, since the “muscle of continence,” the levator ani muscle, and the rectum are in a

normal relationship to each other.

Infants having high imperforate anus require a colostomy in the newborn period, with some kind of pull-through procedure performed at about 2 months of age. Careful assessment

of the genital tracts in females and the genitourinary system in all patients with imperforate anus is imperative because of the very high incidence of associated anomalies,

particularly in children with a high imperforate anus. Many have associated spinal cord anomalies, particularly tethered cord, and all should be evaluated with spinal US and

magnetic resonance imaging MRI. These infants require evaluation for signs of the VACTERRL association (see Esophageal Atresia and Tracheoesophageal Fistula , above),

including careful preoperative cardiac assessment.

Diagnosis of imperforate anus is not difficult. The location of the fistula site may sometimes be a problem. Beading of mucus or meconium along the median raphe of the perineum

and scrotum denotes a low imperforate anus in the male. Air in the bladder, urinating gas or meconium, and a retrograde urethrogram with contrast material may demonstrate the

urinary fistula of the high imperforate anus in the male. In the female, since most of the lesions are low, careful examination of the perineum, fourchette, and vestibule of the vagina

will locate the fistula in most cases. A high fistula in the female may terminate in the vagina and will be harder to demonstrate. If a single perineal opening is seen in the female, a

cloacal abnormality is present with urethra, vagina, and rectum opening into a common urogenital sinus. Colostomy is usually delayed for 24h if no perineal fistula is seen.

Cross-table lateral x-ray of the perineum with the buttock elevated may be done to determine the distance between the end of the rectum and the skin. If there is any doubt of the

level, it is much safer to perform a colostomy than ruin any chance for continence by an injudicious perineal operation.

Pena and DeVries have devised a posterior sagittal approach for repair of high imperforate anus, dividing the levator ani and external sphincter complex in the midline posteriorly

and bringing down the rectum after sufficient length is achieved. The muscles are then reconstructed and sutured to the rectum. Initial reports of results with the posterior sagittal

anorectoplasty have been encouraging for both the primary and secondary procedures for high imperforate anus as well as cloacal anomalies. Pena also recommends this

approach in the female with a rectovestibular fistula.

JAUNDICE

Biliary Atresia

Pathologic jaundice implies persistent elevation of the direct bilirubin level (> 2 weeks, > 2 mg/dL) and may be consequent to cholestasis or obstruction. The incidence of biliary

atresia is approximately 1 in 20,000 births, and the condition affects not only the extrahepatic bile ducts but also the liver, which accounts for the biochemical overlap with many of

the cholestatic causes of jaundice. Originally, biliary atresia was thought to be a developmental anomaly. There is recent suggestive evidence, however, that the condition may have

an immunologic basis. Infectious etiologies have been proposed but never substantiated.

The obliterative process involves the common duct, cystic duct, one or both hepatic ducts, and the gallbladder, in a variety of combinations. Approximately 25 percent of the

patients have coincidental malformations, often associated with polysplenia and may include intestinal malrotation, preduodenal portal vein, and intrahepatic vena cava.

Abdominal exploration in an infant with biliary atresia should commence with inspection of the left upper quadrant to determine the status of the spleen and thereby alert the

surgeon to the possibility of coexisting anomalies should polysplenia be encountered.

Clinical Manifestations

Jaundice, a constant finding, is usually present at birth or shortly thereafter but may go undetected or may be regarded as “physiologic” until the child is 2 or 3 weeks old.

Initially, the growth and weight gain are normal, but in later stages retarded growth is apparent. As the liver becomes progressively more fibrotic, the patients develop stigmata of

portal hypertension, particularly splenomegaly.

Diagnosis

No single test or combination of studies is absolutely reliable but with properly selected tests, it is usually possible to discriminate between cholestatic and obstructive jaundice.

Initially, the synthetic functions of the liver are unimpaired. Thus, the serum albumin level and clotting mechanism are normal. In many centers the nuclear scan using technetium

99m IDA (DISIDA), performed after pretreatment of the patient with phenobarbital, has proven to be an accurate and reliable study. If radionuclide appears in the intestine,

extrahepatic bile duct patency is ensured. If radiopharmaceutical is normally concentrated by the liver but not excreted despite treatment with phenobarbital, and the metabolic

screen, particularly alpha1-antitrypsin determination, is normal, the presumptive diagnosis is biliary atresia. This examination, particularly when complemented by percutaneous

needle biopsy of the liver, will establish a diagnosis with a high degree of certainty.

Complementary studies include abdominal US. This examination is reliable only when performed in the fasting patient. It should be emphasized that the presence of a gallbladder

does not exclude the diagnosis of biliary atresia; in approximately 15 percent of these patients the distal biliary tract is patent although the proximal ducts are atretic. It is worth

noting that the intrahepatic bile ducts are never dilated in the patient with biliary atresia. The sonographer must be alert to the possibility that parallel vascular structures in the porta

may be mistakenly interpreted as patent bile ducts. Doppler US will usually resolve confusion.

Neonatal jaundice also may be caused by the inspissated bile syndrome. This term is applied to patients with normal biliary tracts who have persistent obstructive jaundice.

Increased viscosity of bile and obstruction of the canaliculi are implicated as causes. The condition has been seen in infants receiving parenteral nutrition and is also encountered

secondary to hemolysis or cystic fibrosis. In some instances, no etiologic factors can be defined.

Treatment

Historically, a variety of innovative operations have been attempted to promote bile flow from the liver in infants with biliary atresia. Only the hepatoportoenterostomy, developed by

Kasai, has stood the test of time and demonstrated promise as a procedure that not only will provide relief of jaundice but also may result in cure. The procedure is based on

Kasai's observation that the fibrous tissue at the porta hepatis invests microscopically patent biliary ductules that, in turn, communicate with the intrahepatic ductal system.

Transecting this fibrous tissue, invariably encountered cephalad to the bifurcating portal vein, opens these channels and establishes bile flow into a surgically constructed intestinal

conduit, usually a Roux en Y limb of jejunum . The likelihood of surgical success is increased if the procedure is accomplished before the infant attains the age of 8

weeks. The outlook is poor for patients after the twelfth week. Bile drainage is anticipated when the operation is carried out early; unfortunately, bile flow does not necessarily imply

cure. Prognostic indicators include the rate at which the serum bilirubin level returns toward normal. It has been observed that in patients operated upon before 60 days, jaundice

resolves in approximately 2 months, whereas infants having corrective surgery after 60 days rarely become anicteric or do so only after 6 months. Further, in the latter group the

transaminases often remain elevated. The outcome is most favorable when the serum bilirubin reaches a level less than 1 mg./dL. Hepatic fibrosis may progress even when bile

drainage is achieved. Postoperative cholangitis continues to plague infants having successful portoenterostomy procedures. The incidence and severity of cholangitis may be

reduced by external venting of the surgically created biliary conduit and by the long-term administration of antibiotics. Despite these measures, the problem of ascending infection

has not been eliminated. Reoperation, with resectional debridement of the portoenterostomy anastomosis, has rescued selected children with intractable cholangitis. Portal

hypertension and its sequelae also jeopardize the outcome for some patients even when they have been relieved of jaundice. Gastrointestinal hemorrhage from esophageal varices

usually can be managed successfully by endoscopic sclerotherapy or variceal ligation. For some patients portosystemic shunting has been successful in controlling hemorrhage

from esophageal varices.

While “cure” may be attained in only 25 to 30 percent of patients after hepatoportoenterostomy, significant palliation and prolongation of life with the native liver has been achieved

routinely with the probability of 5 year survival exceeding 60 percent. For the child afflicted with biliary atresia in whom the Kasai operation fails, or succeeds only temporarily, liver

transplantation remains the final hope for salvage. It is generally acknowledged that a prior Kasai operation does not adversely affect on the results of subsequent transplantation.

In the era of orthotopic and living related transplantation there is little justification for repeated operations attempting to salvage a failed Kasai operation. Biliary atresia has been the

most common indication for transplantation in pediatric recipients, and the 1- year survival rate exceeds 80 percent.

Biliary Hypoplasia

In some infants coming to surgery with a presumptive diagnosis of biliary atresia, an operative cholangiogram may demonstrate the gallbladder and extrahepatic biliary system to be

patent, albeit diminutive hence, biliary hypoplasia. Hypoplasia of the extrahepatic biliary system is associated with hepatic parenchymal disorders that cause severe intrahepatic

cholestasis. Included among these are alpha 1-antitrypsin deficiency and arteriohepatic dysplasia (Alagille's syndrome). The primary pathology resides within the liver and not the bile

ducts; therefore, portal dissection and portoenterostomy are not indicated in these patients. Rather, a generous liver biopsy is obtained and the operation terminated.

Choledochal Cyst

There have been numerous descriptions and classifications based on the location and anatomy of the choledochal cyst. Among the most useful is the classification proposed by

Alonso-Lej. The type I cyst characterized by fusiform dilatation of the bile duct into which the cystic duct enters is the most common and clinically relevant. Choledochal cyst is most

appropriately considered the predominant feature in a constellation of pathologic abnormalities within the pancreatic-biliary system. Frequently associated with choledochal cyst are

anomalous junction of the pancreatic duct and common bile duct, distal bile duct stenosis, intrahepatic ductal dilatation, abnormal histology of the common bile duct, and hepatic

histology ranging from normal to cirrhotic. These features are encountered in varying degrees and combinations and constitute the anatomic spectrum of the malformation.

The causation of choledochal cyst is controversial. Babbit proposed an abnormal pancreatic biliary duct junction, with the formation of a “common channel” into which pancreatic

enzyme secretions are discharged, with resulting weakening of the bile duct wall by gradual enzymatic destruction, leading to dilatation, inflammation, and finally cyst formation. It

should be noted, however, that not all patients with choledochal cyst demonstrate an anatomic common channel.

Choledochal cyst is more common in females than in males (4:1). The so- called classic symptom complex of pain, mass, and jaundice is actually encountered in fewer than half the

patients. The more usual presentation is that of episodic abdominal pain, often recurrent over months or years, and generally associated with only minimal jaundice that may

escape detection. If the condition persists unrecognized, sequelae including cholangitis, cirrhosis, and portal hypertension are almost inevitable.

Diagnosis

With the increasing use of antenatal US, choledochal cyst is frequently diagnosed in the fetus. For the older child or adolescent, US and CT scanning are the diagnostic mainstays.

These studies will demonstrate the dimensions of the cyst and define its relationship to the vascular structures in the porta, as well as the intrahepatic ductal configuration.

Endoscopic retrograde cholangiopancreatography (ERCP) is reserved for patients in whom confusion remains after evaluation by less invasive imaging modalities.

Treatment

The surgical options include internal drainage by cystenterostomy and surgical excision. The morbidity from the former is excessive. The cyst wall is composed of fibrous tissue and

is devoid of mucosal lining. Anastomotic obstruction from scarring is inevitable. Further, the thick-walled fibrous cyst does not contract after drainage but rather persists as a

receptacle for stagnant bile, and complications related to biliary stasis militate against internal drainage procedures. An additional, and perhaps the most serious, consequence of

cyst retention is the development of malignancy arising within the cyst wall. The incidence of this aggressive and highly lethal neoplasm further supports the recommendation for

cyst resection.

In most circumstances, the caliber of the common hepatic duct cephalad to the choledochal cyst is normal. Successful resection of the cyst requires circumferential dissection,

entering the posterior plane between the cyst and portal vein to accomplish removal. The pancreatic duct, which may enter the distal cyst, is vulnerable to injury during distal cyst

excision but can be avoided by not dissecting into the pancreatic parenchyma.

For the patient in whom the anatomy of the porta is obscured and distorted by pericystic inflammation, an alternative technique is proposed. An arbitrary plane is entered within the

posterior wall of the cyst that allows the inner lining of the back wall to be dissected free from the outer layer that directly overlies the portal vascular structures. The lateral and

anterior cyst, as well as the internal aspect of the back wall, is removed. The outer posterior wall remains behind. In either circumstance, cyst excision is accomplished, with

reconstruction using normal or near-normal proximal bile duct and a mucosal union between the biliary system and intestinal tract. The likelihood of postoperative anastomotic

stricture with attendant sequelae is minimized. Further, the risk of malignant tumor is reduced although not completely eliminated.

DEFORMITIES OF THE ABDOMINAL WALL

Embryology

The abdominal wall is formed by four separate embryologic folds—cephalic, caudal, and right and left lateral folds—each of which is composed of somatic and splanchnic layers.

Each of the folds develops toward the anterior center portion of the coelomic cavity, joining to form a large umbilical ring that surrounds the two umbilical arteries, the vein, and the

yolk sac or omphalomesenteric duct. These structures are covered by an outer layer of amnion, and the entire unit composes the umbilical cord. Between the fifth and tenth weeks

of fetal development the intestinal tract undergoes a rapid growth outside the abdominal cavity within the proximal portion of the umbilical cord. As development is completed, the

intestine gradually returns to the abdominal cavity. Contraction of the umbilical ring completes the process of abdominal wall formation. Failure of the cephalic fold to close results in

sternal defects (such as congenital absence of the sternum or the pentalogy of Cantrell. Failure of the caudal fold to close results in exstrophy of the bladder and, in more extreme

cases, exstrophy of the cloaca. Interruption of central migration of the lateral folds results in omphalocele. Gastroschisis, originally thought to be a variant of omphalocele, probably

results from a fetal accident in the form of intrauterine rupture of a hernia of the umbilical cord.

Umbilical Hernia

Failure of timely closure of the umbilical ring leaves a central defect in the linea alba. The resulting umbilical hernia is covered by normal umbilical skin and subcutaneous tissue, but

the fascial defect allows protrusion of abdominal content . Hernias less than a cm in size at the time of birth usually will close spontaneously by three years of life.

Sometimes the hernia is large enough that the protrusion is disfiguring and disturbing to both the child and the family. In such circumstances early repair may be advisable. When

the defect is small and spontaneous closure likely, delay of surgical correction until 4 or 5 years of age is appropriate. Incarceration is rarely seen in an umbilical hernia. Unlike

treatment for inguinal hernia of infants and young children, attempts at reduction of an incarcerated umbilical hernia are unwise. Repair of uncomplicated umbilical hernia is

performed through a small curving infraumbilical incision that fits into the skin crease of the umbilicus. The fascial defect is repaired with permanent or long-lasting absorbable,

interrupted sutures in a transverse plane. Fascial flaps or other complicated umbilical hernia repairs that have been recommended for adult patients are unnecessary in children.

The umbilicus should never be excised in the repair of umbilical hernias in the childhood period.

Patent Urachus

During the development of the coelomic cavity, there is free communication between the urinary bladder and the abdominal wall through the urachus, which exits adjacent the

omphalomesenteric duct. Persistence of this tract results in a communication between the bladder and the umbilicus . The first sign of a patent urachus is moisture or

urine flow from the umbilicus; consequently, recurrent urinary tract infection can result. The urachus may be partly obliterated, with a remnant remaining beneath the umbilicus in the

extraperitoneal position as an isolated cyst, which may be identified by US. Such a cyst usually presents as an inflammatory mass inferior to the umbilicus. Initial treatment is

drainage of the abscess with cyst excision as a separate procedure once the inflammation has resolved. Diagnosis of patent urachus is most reliably made by a cystogram in the

lateral projection. Surgical correction is carried out via extraperitoneal exposure of the infraumbilical area. After identification, excision of the urachal tract with closure of the bladder

is curative.

Omphalocele

Prenatal US will identify many of these defects permitting genetic evaluation and counselling. Postnatally, an omphalocele  presents as a mass of bowel and solid

viscera in the central abdomen, covered by translucent membrane. The size varies from about 1 cm in diameter to huge defects containing much or all of the abdominal viscera. In

the latter forms, the bowel has lost its right of domain in the abdominal cavity, and closure is difficult. Frequently the liver occupies much of the defect and does not tolerate

compression. The diagnosis is made by inspection. Infants born with omphaloceles are prone to other anomalies. There is a 60 to 70 percent incidence of associated anomalies,

especially cardiac and chromosomal abnormalities. Special syndromes such as exstrophy of the cloaca (vesicointestinal fissure) and the Beckwith-Wiedemann constellation of

anomalies (macroglossia, macrosomia, hypoglycemia, and visceromegaly) include omphalocele.

Immediate treatment after delivery of an infant with omphalocele consists of covering the lesion with saline-soaked gauze and wrapping the trunk circumferentially. No pressure

should be placed on the omphalocele sac in an effort to reduce its contents, because pressure can lead to rupture of the sac or may interfere with abdominal venous return, or

impede respiratory effort. The omphalocele sac can be treated with desiccating substances such as Mercurochrome, but most infants in the United States are treated surgically.

Indications for nonoperative therapy of an omphalocele are (1) a newborn with a giant omphalocele and other life- threatening anomalies whose correction takes precedence over

repair of the omphalocele, (2) the neonate with other anomalies that complicate a surgical repair of the omphalocele, and (3) a newborn with severe associated anomalies that may

not be consistent with survival.

When the abdomen cannot be closed primarily without undue tension, a temporary measure is placement of a “silo” of Silastic material sutured to the fascia around the

circumference of the defect as an exterior cover without skin. This technique also can be used for gastroschisis when necessary. The main principle in the use of the plastic material

is steady pressure with gradual reduction of the plastic envelope within 7 days to close the fascia without excessive tension. Today most infants, even those with large

omphaloceles, can be salvaged. The persistent mortality rate of 20 to 30 percent from pediatric centers reflects the serious cardiac and chromosomal anomalies associated with this

malformation.

Gastroschisis

Shaw first suggested that gastroschisis is simply a hernia of the umbilical cord that ruptures after the complete development of the abdominal wall. The defect that permits escape

of the intestines is located at the junction of the umbilicus and normal skin. The defect is almost always to the right of the umbilicus. Infants with gastroschisis have a large amount

of intestine on the surface of the abdominal wall . The umbilicus becomes partly detached, allowing free communication with the abdominal cavity. The intestine lying

free outside of the abdominal cavity may be glistening, moist, and normal in appearance, suggesting that the rupture occurred immediately before or during delivery of the infant.

More commonly, the intestine is thick, edematous, discolored, and covered with an exudate. Unlike infants born with omphalocele, associated anomalies seen with gastroschisis are

confined to bowel atresia, further substantiating the mechanics of this abnormality. Currently, prenatal US may detect gastroschisis, permitting counselling and elective controlled

delivery .

Treatment

All infants born with gastroschisis require urgent surgical treatment. The intestine can be returned to the abdominal cavity, and a secure, primary surgical closure of the abdominal

wall is possible in many instances. Mechanical stretching of the abdominal wall aids in successful primary closure; however, for those infants whose intestine has become thickened

and edematous, the construction of an extraabdominal compartment from Silastic sheeting is beneficial . As in the surgical correction of omphalocele, the prosthetic

pouch allows gradual enlargement of the abdominal cavity and accommodation of the intestines. Care must be taken so that increased abdominal pressure does not cause inferior

vena cava compression that may impede venous return to the heart or diaphragmatic pressure preventing normal respiratory excursion. Intestinal function may not return for several

weeks, and is especially delayed if the bowel is thickened and edematous. In these infants, the advent of I.V. alimentation has been lifesaving. The survival rate for infants with

gastroschisis exceeds 90 percent in many series.

Exstrophy of the Cloaca (Vesicointestinal Fissure)

Exstrophy of the cloaca represents one of the severest forms of embryologic derangement. In infants with cloacal exstrophy, the normal ventral closure of the pelvis and the

abdominal wall is imperfect. Major components of cloacal exstrophy are (1) omphalocele, (2) exstrophy of the bladder, (3) external intestinal fistula through the bladder

(enterovesical fistula), (4) epispadias in males, (5) imperforate anus, and (6) foreshortened colon. In addition, there is often an associated orthopedic deformity of the lower limbs.

Treatment of these complicated anomalies should be done in conjunction with a pediatric urologist and pediatric orthopedist to gain maximal function with a minimal number of

procedures. An ileostomy and primary closure of the omphalocele usually are possible. The small piece of distal colon should be preserved for future anal and vaginal

reconstruction. Timing of bladder and urinary reconstruction needs to be individualized, depending on the child's anatomy. While most patients suffer a number of physical

limitations, many have the potential for functional rehabilitation, which justifies aggressive surgical efforts on their behalf.

Prune-Belly Syndrome (Eagle-Barret Syndrome)

Prune-belly syndrome is characterized by the findings of lax lower abdominal musculature, dilated urinary tract, including the bladder, and undescended testes bilaterally. It occurs

almost exclusively in males . Despite the impressive dilatation of the urinary tract, most of the children with prune-belly syndrome have adequate renal parenchyma for

growth and development, at least early in life. In the past, aggressive “reconstruction” of the urinary tract was attempted, but currently a conservative approach is favored unless

there is a specific area that requires drainage due to obstruction, not just dilation.

The testes are invariably intraabdominal and bilateral orchidopexy can be performed in conjunction with abdominal wall reconstruction at 6 to 12 months of age. Despite orchiopexy,

fertility in a boy with prune-belly syndrome is unlikely. Abdominal wall repair is best accomplished with a large curving transverse incision in the lower abdomen extending into the

flanks, the so-called “smile” incision. The combination of conservative treatment of the urinary tract and aggressive treatment of the undescended testes and abdominal wall has

given many of these children a reasonably normal lifestyle.

Inguinal Hernia

Inguinal hernia results from a failure of closure of the processus vaginalis, a finger-like projection of the peritoneum that accompanies the testicle as it descends into the scrotum.

Closure of the processus vaginalis should occur a few months prior to birth, which explains the high incidence of inguinal hernias in premature infants. In children, the male:female

incidence of inguinal hernia is 10:1. Infants are at high risk for incarceration of an inguinal hernia because of the narrow inguinal ring. Differentiating between an incarcerated

inguinal hernia and a hydrocele can be difficult, even with scrotal transillumination, and the symptomatic infant with a scrotal inguinal bulge must be evaluated by an experienced

surgeon. Most often the incarcerated hernia can be reduced. The infant is sedated, and moderate bimanual pressure is applied by compressing the sac from below while a gentle

counterforce downward is provided from the examiner's hand above the inguinal ring. Occasionally, these hernias will reduce spontaneously after sedation is given and the

continuous struggling and crying are terminated. Following reduction of the incarcerated hernia, the child is admitted for observation, and herniorrhaphy is performed within the next

24 h to prevent recurrent incarceration. If the hernia cannot be reduced, or if intestinal obstruction is obvious, emergency operation, with reduction and repair, is necessary.

When the diagnosis of inguinal hernia is made in an otherwise normal child, operative repair should be planned, since spontaneous resolution does not occur. The frequency of a

patent processus vaginalis on the side opposite the obvious hernia remains controversial. Data from laparoscopic evaluation of the normal appearing side revealed an incidence of

greater than 30 percent patent processus vaginalis, regardless of the age or gender of the patient.

An inguinal hernia in a female frequently contains an ovary rather than intestine. Although the gonad usually can be reduced into the abdomen by gentle pressure, it often

prolapses in and out until surgical repair is carried out. In some patients, the ovary and fallopian tube constitute one wall of the hernial sac (sliding hernia), and in these patients the

ovary can be reduced effectively only at the time of operation. If the ovary is irreducible, prompt hernia repair is indicated to prevent ovarian torsion or strangulation.

When fluid fills the processus vaginalis, the patient has a hydrocele. The hydrocele may be associated with a hernia, may have a patent processus vaginalis too small for intestine

to pass into (a communicating hydrocele), or may have no communication with the peritoneal cavity. When a hydrocele is diagnosed in infancy and there is no evidence of a hernia,

observation is proper therapy until the child is older than 12 months. If the hydrocele has not disappeared by 12 months, invariably there is a patent processus vaginalis, and

operative hydrocelectomy with excision of the processus vaginalis is indicated. When the first signs of a hydrocele are seen after 12 months of age, the patient should undergo

elective hydrocelectomy, which in a child is always performed through a groin incision. Aspiration of hydroceles is discouraged, since almost all without a patent processus vaginalis

will resorb spontaneously, and those with a communication to the peritoneum will recur and require operative repair eventually.

Operative repair of an inguinal hernia or hydrocele is accomplished through a small incision in a skin crease in the groin directly over the internal inguinal ring. The external oblique

muscle is opened, and the cord structures and hernia sac are elevated into the wound, taking care not to grasp the vas deferens. The hernia sac is dissected to the internal ring and

doubly suture ligated. The distal part of the hernia sac is dissected down to the testicle and widely opened to prevent a postoperative hydrocele. When the hernia is very large and

the patient very small, tightening of the internal inguinal ring or even formal repair of the inguinal floor may be necessary, although the vast majority of children do not require any

treatment beyond high ligation of the hernia sac. Inguinal hernias in children recur in less than 1 percent of patients, and recurrences usually result from missed hernia sacs at the

first procedure, a direct hernia, or a missed femoral hernia. All children should have local anesthetic administered either by caudal injection or by direct injection into the wound.

Spinal anesthesia in preterm infants decreases the risk of postoperative apnea when compared with general anesthesia.

GENITALIA

Cryptorchidism

The term undescended testicle describes that testicle that has been interrupted in its normal route of descent into the scrotum. Such a testicle may reside in the posterior abdomen,

in the internal inguinal ring, in the inguinal canal, or even at the external ring. The testicle begins as a thickening on the urogenital ridge in the fifth to sixth week of embryologic life.

In the seventh and eighth months the testicle descends along the inguinal canal into the upper scrotum, and with its progress the processus vaginalis is formed and pulled along

with the migrating testicle. At birth, approximately 95 percent of infants have the testicle normally positioned in the scrotum.

A distinction should be made between the undescended testicle and the ectopic testicle. An ectopic testis, by definition, is one that has passed through the external ring in the

normal pathway and then has come to rest in an abnormal location overlying either the rectus abdominis or external oblique muscle, or the soft tissue of the medial thigh, or behind

the scrotum in the perineum. A congenitally absent testicle results from failure of normal development or an intrauterine accident leading to loss of blood supply to the developing

testicle.

Clinical Manifestations

Usually a unilateral undescended testicle can be felt in the inguinal canal or in the upper scrotum. Occasionally, the testicle will be difficult or impossible to palpate, indicating either

an abdominal testicle or congenital absence of the gonad. Patients with a nonpalpable testicle are routinely laparoscoped before inguinal exploration to identify an abdominal

testicle. In patients with bilateral undescended testicles, it is appropriate to study the serum gonadotropin level, since the serum luteinizing hormone level is elevated in patients

without gonadal tissue.

Reasons for surgical placement of the testicle in the scrotum are

(1) diminished spermatogenesis, (2) malignant degeneration, (3) increased trauma (to a testicle located at the pubic tubercle), (4) increased incidence of torsion, and (5) psychological. The reason for malignant degeneration is not established, but the evidence points to an inherent

abnormality of the testicle that predisposes it to incomplete descent and malignancy rather than malignancy as a result of an abnormal environment.

Males with bilateral undescended testicles are infertile. When the testicle is not within the scrotum, it is subjected to a higher temperature, resulting in diminishing spermatogenesis.

Mengel and coworkers studied 515 undescended testicles by histology and demonstrated a decreasing presence of spermatogonia after 2 years of age. Consequently it is now

recommended that the undescended testicle be surgically repositioned by 2 years of age. Despite orchidopexy, the incidence of infertility is approximately two times higher in men

with unilateral orchidopexy compared to men with normal testicular descent.

Treatment

The use of chorionic gonadotropin occasionally has been effective in patients with bilateral undescended testes, suggesting that these patients are more apt to have a hormone

insufficiency than children with unilateral undescended testicle. If there is no testicular descent after a month of endocrine therapy, operative correction should be undertaken. A

child with unilateral cryptorchidism should have surgical correction of the problem.

Some patients who have an absent testis are greatly bothered by this anatomic deficiency. Prostheses of all sizes are now available and can be simply inserted into the scrotum,

achieving normal appearance and a normal structure for palpation. Any patient who has an undescended testicle corrected surgically should be examined yearly by his surgeon

until his midteen years. At that time, the individual should undergo thorough explanation about the possibility of malignant degeneration and be instructed in self-examination, which

should be carried out at least twice a year for life.

Vaginal Anomalies

Anomalies of development of the vagina constitute a spectrum from simple defects (imperforate hymen) to more complex forms of vaginal atresia, including distal, proximal, and,

most severe, complete. These defects are produced by abnormal development of müllerian ducts and/or urogenital sinus. The diagnosis is made most often by physical

examination. Secretions into the obstructed vagina produce hydrocolpos, which may present as a large abdominal mass. US may help delineate the anatomy. The type of surgical

repair depends on the extent of the defect. Simple imperforate hymen or a low transverse septum may be excised readily by a perineal approach. Other forms of vaginal atresia

require complex reconstructive surgery, which may include mobilizing vaginal remnants down to the perineum, creating skin flaps, or using a colon segment as a neovagina.

Ovarian Cysts and Tumors

Ovarian cysts and tumors occur infrequently in childhood. They may be classified broadly as nonneoplastic or neoplastic. Nonneoplastic lesions include cysts (simple, follicular,

inclusion, paraovarian, or corpus luteum), endometriosis, and inflammatory lesions. Neoplastic lesions are classified based on the three primordia that contribute to the ovary:

mesenchymal components of the urogenital ridge, germinal epithelium overlying the urogenital ridge, and germ cells migrating from the yolk sac.

Most commonly, children with an ovarian mass complain of abdominal pain. Other signs and symptoms include a palpable abdominal mass, evidence of urinary obstruction,

symptoms of bowel obstruction, and endocrine imbalance. The surgical approach depends on the appearance of the mass at operation, i.e., whether it is benign-appearing or is

suspicious for malignancy. In the case of a simple, benign ovarian cyst, conservative excision is recommended, sparing ovarian tissue. If a lesion appears malignant, (1) ascites and

peritoneal washings should be collected for cytologic study, (2) the liver and diaphragm are inspected carefully for metastatic disease, (3) an omentectomy is performed, (4) pelvic

and paraaortic lymph nodes are biopsied, (5) the primary tumor is resected completely, and (6) the contralateral ovary is carefully inspected and, if appropriate, bisected and

biopsied.

An increasing number of ovarian cysts are being detected by prenatal US. In the past, surgical excision was recommended for all cysts greater than 5 cm in diameter because of

the perceived risk of ovarian torsion. More recently, it has become apparent from serial US examinations that many of these lesions will resolve spontaneously. Complex cysts of

any size require surgical intervention. Surgeons have four options for managing simple cysts: (1) follow the lesion sonographically and operate if it fails to resolve over several

months, (2) drain the cyst percutaneously by ultrasound- guided needle aspiration, (3) drain the cyst by laparoscopically guided needle aspiration, and (4) excise the cyst by

conventional operation.

Ambiguous Genitalia (Intersex Syndromes)

Normal sexual differentiation occurs in the sixth fetal week. In every fetus, wolffian (male) and müllerian (female) ducts are present until the onset of sexual differentiation. Normal

sexual differentiation is directed by the Y chromosome in a genetic switch initiated by the sex determining region of the Y chromosome (SRY). SRY is located on the distal 1A1 end

of the short arm of the Y chromosome, adjacent to the pseudoautosomal region where small deletions in this area were known to be associated with sex reversal. Thus, SRY

provides a genetic switch that initiates gonadal differentiation in the mammalian urogenital ridge. Müllerian inhibiting substance (MIS), a member of the transforming growth factor

(TGF-b) family, results in regression of the müllerian duct, the anlagan of the uterus, Fallopian tubes, and the upper vagina. MIS gene transcription is initiated by tissue specific

(gonadal ridge) and developmentally appropriate expression of the triple alpha-helical SRY protein that binds to the promoter region of the MIS gene in a sequence specific manner.

Simplistically, in the absence of SRY in the Y chromosome and in the presence of a duplicated X chromosome, the urogenital ridge differentiates as an ovary. In the absence of MIS

that is produced by the Sertoli cells of the differentiated testis, the müllerian duct derivatives, i.e., the vagina, uterus, and Fallopian tubes, are preserved or fail to undergo

regression. Thus the female phenotype prevails. In order for the male phenotype to develop, the embryo must have a Y chromosome, the SRY must be normal without point

mutations or deletions, testosterone and MIS must be produced by the differentiated gonad, and the tissues must respond to these ligands via an appropriate receptor.

Testosterone stimulates maturation of wolffian duct structures into epididymis, vas deferens, and seminal vesicles; simultaneously, the MIS produces regression of the female

structures. Any disruption of the orderly steps in sexual differentiation may be reflected clinically as variants of the intersex syndromes . These may be classified as (1)

true hermaphroditism (with ovarian and testicular gonadal tissue), (2) male pseudohermaphroditism (testicles only), (3) female pseudohermaphroditism (ovarian tissue only), and (4)

mixed gonadal dysgenesis (usually underdeveloped or imperfectly formed gonads).

Male pseudohermaphroditism is found in genotypic males with bilateral testes; however, the duct structures of many of these patients differentiate partly as phenotypic females,

resulting from defects in androsynthesis or incomplete müllerian regression. Female pseudohermaphroditism is found most commonly in patients with congenital adrenal

hyperplasia who are unable to synthesize cortisol due to abnormally low levels of any one of five enzymes. In 90 percent of cases, deficiency of 21-hydroxylase causes

adrenocorticotropic hormone (ACTH) to stimulate the secretion of excessive quantities of adrenal androgen, which masculinizes the developing female. These infants are prone to

salt loss and can experience collapse at about 1 week of age. The rarest intersex form, that of the true hermaphrodite, is usually found with XX karyotype. These children have

ambiguous genitalia and their gonad pattern may show an ovary and a testicle, or an ovotestis.

In the differential diagnosis of patients with intersex anomalies, the following diagnostic steps are necessary:

(1) evaluation of the genetic background and family history;

(2)assessment of the anatomic structures by physical examination and x-ray studies;

(3) chromosome studies;

(4) determination of biochemical factors in serum and urine; and

(5)when necessary, laparotomy and gonadal biopsy.

 Genetic females should be assigned the female gender, regardless of the degree of virilization. For genetic males, the gender assignment will depend on anatomic considerations, specifically the size of the phallus, since at this time satisfactory surgical techniques do not exist to reconstruct an inadequate

phallus. The physicians presented with a newborn infant with ambiguous genitalia must make the gender assignment rapidly, to minimize the emotional impact on the family, and

accurately, since a change later causes irreparable anguish. Assignment to one of four major groups of defects described above can be made readily using two screening criteria:

(1)the presence of gonadal symmetry or asymmetry, and (2)the presence of a chromatin mass or Barr body or the absence of fluorescence of the distal long arm of the Y

chromosome. After the correct designation to one of the major categories, the specific pathoetiology can be determined at a more deliberate pace.

Gonadal symmetry is determined by the position of one gonad relative to the other, either above or below the external inguinal ring. If the gonadal position is symmetric, both

gonads lie either above or below the inguinal ring, suggesting a diffuse etiologic basis for the abnormality. For example, in either male or female pseudohermaphroditism, a

biochemical defect affects both gonads equally, such that the gonads are symmetric. In contrast, in mixed gonadal dysgenesis or true hermaphroditism, asymmetry is observed if

there is a predominance of testicular tissue on one side and ovarian tissue on the other side, in which case the testicular gonad is descended and the ovarian gonad is

undescended.

With more than one X chromosome present in the karyotype, the inactivated X chromosome (Barr body) can be found tangentially in the nucleus, which is the case with female

pseudohermaphroditism (adrenogenital syndrome) or in most cases of true hermaphroditism. Conversely, Barr bodies are absent in patients with male pseudohermaphroditism and

mixed gonadal dysgenesis. At centers that perform analyses to mark the distal long arm of the Y chromosome, instead of chromatin analysis with Barr bodies, fluorescent Y positive

nuclei are seen with male pseudohermaphrodites and mixed gonadal dysgenesis, and fluorescent Y negative nuclei are seen with female pseudohermaphrodites and true

hermaphrodites. With this algorithm, a preliminary diagnosis that assigns the patient to one of four major groups can be established with 80 to 90 percent accuracy within the first 24

hours of life.

After complete evaluation, certain plastic surgical procedures are required to harmonize the external genitalia with the sex of rearing. Operations to reduce the size of the enlarged

clitoris have been developed that spare the sensation and function of the clitoris. Plastic procedures to exteriorize the vagina or separate it from the urethra are necessary in

patients born with a urogenital sinus. When male assignment is appropriate for an infant with ambiguous genitalia, hypospadias repair will be necessary. When contradictory

gonads or ovotestes are present, removal of these structures is required to prevent the possibility of hormone secretion or malignant degeneration. For psychological adjustment of

some teenage male patients with inadequate or absent gonads, the insertion of testicular prostheses may prove beneficial. Children with endocrine deficiency may require lifetime

exogenous supplementation. Prompt recognition of infants with intersex anomalies, followed by appropriate sex assignment and proper treatment, prevents the social and

psychological derangements that have occurred in the past because of delayed diagnosis or inappropriate gender assignment.

NEOPLASTIC DISEASE

Cancer is the second leading cause of death in children. Approximately 11 percent of the deaths of children in the United States are due to malignant diseases . In the past 30 years there has been a marked increase in the survival of patients with childhood cancer. This improvement can be attributed to better diagnostic imaging techniques; new

chemotherapeutic agents; collaborative approaches to surgery, chemotherapy, and radiation therapy; and multi-institutional studies evaluating new treatments and protocols. This

unified approach to diagnosis, staging, and therapy has proved useful in the management of the more common pediatric solid malignancies, such as Wilms' tumor, hepatic tumors,

rhabdomyosarcoma, neuroblastoma, and teratoma. Advances in the understanding of molecular biology, immunology, pharmacology, and tumor biology surely will lead to

improvements in care in the next decade. Best results are achieved in institutions with special skill in the care of children and with access to the latest multimodality and

multidisciplinary protocols.

Wilms' Tumor

Wilms' tumor is an embryonal neoplasm of the kidney that usually presents as an asymptomatic mass in the flank or upper abdomen. The peak age of incidence is between 1 and 5

years. This tumor has been associated with congenital anomalies such as aniridia, the Beckwith-Wiedemann syndrome, urinary tract defects, hemihypertrophy, and chromosomal

deletion, suggesting a possible hereditary influence. Specific Wilms' tumor suppressor genes have been discovered and cloned (WT1 and WT2), mutations or deletions of which

may be responsible for the development of Wilms' tumors.

Before operation, all patients suspected of Wilms' tumor should be evaluated radiographically. Abdominal and chest CT scans and US are the mainstays of the work-up. US

confirms the presence of a mass and localizes it to the kidney. It can demonstrate the presence of renal vein or vena caval extension, crucial information before embarking on

surgical intervention. The CT scan usually will show a large intrarenal mass . Furthermore, the scan provides important preoperative data such as the tumor status of the

contralateral kidney and the presence of local or distant spread. MRI is finding an increasing role in the imaging of these tumors.

The key to staging and treatment is surgical intervention. A generous transabdominal transverse incision is used to ensure adequate exposure for removing the primary tumor, to

evaluate the opposite kidney, and to inspect the rest of the abdomen. The tumor and kidney are completely resected with care to avoid tumor spillage. Whenever possible the renal

vein should be clamped before the tumor is mobilized, to prevent tumor embolization. If there has been contiguous spread of the tumor into adjacent organs, the operation may be

expanded to include part of the liver, spleen, diaphragm, pancreas, or stomach. Lymph nodes are sampled to assist with staging.

Following operative removal of a Wilms' tumor, the need for chemotherapy and/or radiation therapy is determined by the histology of the tumor and the clinical stage of the patient. Patients with disease confined to one kidney, totally removed surgically, receive a short course of chemotherapy and can expect a 97 percent 4-year survival, with

tumor relapse rare after that time. Patients with Stage II and III disease with favorable histology receive a longer course of combination chemotherapy. Patients with Stage IV

disease or unfavorable histology require longer and more intensive chemotherapy. Radiation therapy is used for the advanced stages. Even in Stage IV, cure rates of 80 percent

are being achieved. The survival rates are worse in the small percentage of patients considered to have unfavorable histology. Actinomycin D and vincristine are the major

chemotherapeutic agents used. Adriamycin and cyclophosphamide are used in advanced stages. Despite the enormous contribution of chemotherapy and radiation to improved

survival, surgical excision remains the primary treatment. In selected patients, preoperative chemotherapy is used to shrink massive tumors or to reduce tumor bulk when bilateral

disease is present. In the case of massive tumors, this approach may reduce tumor spill and make operations safer. With bilateral disease it allows for conservation of renal tissue

at the time of resection.

Current protocols designed by the National Wilms' Tumor Study (NWTS) focus on decreasing therapy for low-risk patients and on intensifying therapy for high-risk patients.

Additionally, new strategies are required for children with recurrent disease, since the present outlook with conventional therapy is dismal. Long-term follow-up is required for all

children treated for Wilms' tumor because of the increasing recognition of second malignancies.

Neuroblastoma

Neuroblastoma is the third most common pediatric malignancy. Over 60 percent arise in children under the age of 5 years. Neuroblastomas arise from the neural crest cells and

show different levels of differentiation. The tumor originates most frequently in the adrenal glands, posterior mediastinum, neck, or pelvis but can arise in any sympathetic ganglion.

The clinical presentation depends on the site of the primary and the presence of metastasis.

Two-thirds of these tumors are first noted as an asymptomatic abdominal mass. The tumor may cross the midline, and a majority of patients will already show signs of metastatic

disease. The patient should be evaluated by CT scan and US, which usually show displacement and occasionally obstruction of the ureter of an intact kidney. Since these tumors

derive from the sympathetic nervous system, catecholamines and their metabolites will be produced at increased levels and may produce symptoms. Measurement of VMA and

HVMA in serum and urine aids in the diagnosis and in monitoring adequacy of future treatment and recurrence. Elevations of serum ferritin and neuron-specific enolase levels

correlate with poor prognosis. Increased copy number of the N-myc gene is an important indicator of poor prognosis.

Although CT scan, bone marrow biopsy, and radionuclide scans are important adjuncts to preoperative staging, surgical evaluation and excision, when possible, are essential. The

main hope of cure is to resect the tumor completely, because chemotherapy and radiation therapy have not altered survival significantly in the past 20 years. Abdominal tumors are

approached through a transverse incision, and every attempt is made to resect the tumor completely. Thoracic tumors may be approached through a posterolateral thoracotomy

and often have an intraspinal component necessitating laminectomy and intraspinal removal. Many staging classifications have been developed to predict survival and to stratify

patients for treatment protocols . The most commonly employed are those developed by the Children's Cancer Study Group and the International Neuroblastoma

Staging System.

If the tumor is not resectable, a generous biopsy is obtained for histopathologic classification and determination of N-myc gene copy number, both important determinants of

prognosis. Under current experimental protocols, the children receive several courses of chemotherapy to shrink the tumor and then undergo a “second-look” attempt at resection.

Protocols incorporating bone marrow transplantation have been used for patients with advanced disease. Even with aggressive chemotherapy protocols, the 2-year survival rate for

older children with metastatic disease is 20 percent.

Owing to variability in sites and in biologic behavior, the treatment of neuroblastoma must be individualized. In infants favorable survival may be realized even when there is

metastatic spread to bone marrow, liver, or skin (Stage IVs). Over 85 percent of these patients, if less than one year old, will be completely and spontaneously cured. The

spontaneous regression of tumor seen in many of these patients has led to much investigation of immunotherapy as a possible therapeutic tool. Although cure rates of greater than

80 percent have been achieved in Stages I and II, the poor survival in the higher stages is discouraging and calls for new therapies and further research.

Rhabdomyosarcoma

Rhabdomyosarcoma is a primitive soft tissue tumor that arises from mesenchymal tissues. The head and neck (36 percent), extremities (19 percent), genitourinary tract (21

percent), and trunk (9 percent) are the most common sites of origin, although the tumor can arise virtually anywhere. The clinical presentation of the tumor depends on the site of

origin. The diagnosis is confirmed with incisional or excisional biopsy after evaluation by MRI, CT scans of the affected area and the chest, and bone marrow biopsy. The tumor

grows locally into surrounding structures and metastasizes widely to lung, regional lymph nodes, liver, brain, and bone marrow. The overall survival is 60 percent at 5 years. Prognosis relates to the site of origin, clinical grouping, and histopathology. The prognosis in patients with embryonal pathology is much more favorable than that in patients with alveolar histology. Five-year survival rates are 81 percent in clinical group I, 80 percent in clinical group II, 65 percent in clinical group

III, and 27 percent in clinical group IV. The Intergroup Rhabdomyosarcoma Study (IRS) has recently developed a staging system based on TNM principles that may serve as the

basis for future studies designed to improve survival.

Wide local excision with adequate “clean” margins is the optimal surgical treatment for localized forms of rhabdomyosarcoma. The potential morbidity of radical amputations or

exenteration can be avoided because of progress in chemotherapy and radiation therapy in recent years. Often the approach involves initial biopsy, several courses of

chemotherapy, and resection at a “second-look” operation. The standard chemotherapy is a combination of actinomycin D, vincristine, and cyclophosphamide. Treatment is

individualized based on the site, group, and histology, but all will receive multimodality therapy.

Teratoma

Teratomas are tumors composed of tissue from all three embryonic germ layers. They may be benign or malignant, may arise in any part of the body, and are usually found in

midline structures. Thoracic teratomas usually present as an anterior mediastinal mass. Ovarian teratomas present as an abdominal mass often with symptoms of torsion, bleeding,

or rupture. Retroperitoneal teratomas may present as a flank or abdominal mass. The location incidence of teratomas in children is seen in Table 37-4. The goal of therapy is

complete surgical excision because the success of chemotherapy and/or radiation therapy seen in other pediatric tumors has not been realized in this group of tumors.

Sacrococcygeal Teratoma

Sacrococcygeal teratoma usually presents as a large mass extending from the sacrum in the newborn period. Many tumors have been diagnosed prenatally by US. In fetuses with

evidence of hydrops and a large sacrococcygeal teratoma, prognosis is poor, thus prenatal intervention has been advocated in such patients. The mass may be as small as a few

centimeters in diameter or as massive as the size of the infant (Fig. 37- 36). There is a form of tumor that does not present externally but grows in the presacral space and often

presents later in childhood. The differential diagnosis consists of neural tumors, lipoma, and myelomeningoceles.

Most tumors are identified at birth and are benign, but with advancing age the potential for malignant degeneration is high. Complete resection of the tumor as early as possible is

essential. The rectum and genital structures are often distorted by the tumor but usually can be preserved in the course of resection. The cure rate is excellent if the tumor is

excised completely. Perioperative complications of hypothermia and hemorrhage can occur with massive tumors and may prove lethal in “benign” lesions. With discovery of the

tumor in older infants and children, the results are poor because of the high incidence of malignant degeneration. Chemotherapy is indicated in these older children.

Liver Tumors

More than two-thirds of all liver tumors in children are malignant. Hepatoblastoma is the most common malignancy of the liver in children, with most of these tumors diagnosed

before 4 years of age. Hepatocellular carcinoma is the next most common, with a peak age incidence between 10 and 15 years. Malignant mesenchymomas and sarcomas are

much less common but constitute the remainder of the malignancies. Most children with a liver tumor present with an abdominal mass that is usually painless, which the parents

note while changing the child's clothes or while bathing the child.

The patients are rarely jaundiced but may complain of anorexia and weight loss. Most liver function tests are normal. Alpha-fetoprotein levels are elevated in 90 percent of children

with hepatoblastomas but are increased much less commonly in other liver malignancies. Radiographic evaluation of these children should include a flat-plate abdominal

radiograph, an US study, and a contrast-enhanced abdominal CT scan.

Complete surgical extirpation of the tumor is the primary goal and is essential for cure. For resectable tumors, attempts to reduce the bulk of massive tumors by pretreatment with

chemotherapy have met with limited success. The value of radiotherapy is also limited. Previously, hepatic transplantation for unresectable primary lesions had a high incidence of

carcinomatosis and death; however, recent results are more encouraging. For hepatoblastoma, about half the patients have completely resectable lesions , and about

80 percent of these can be cured with adjunct chemotherapy. Of all patients with hepatoblastomas, only about 70 percent are long-term survivors. Patients with hepatocellular

carcinoma have a worse prognosis because the tumors are frequently multicentric or metastatic. The cure rate for all children with hepatocellular carcinomas is only 25 percent.

TRAUMA

Injuries account for almost half of all pediatric deaths, more than cancer, congenital anomalies, pneumonia, heart disease, homicide, and meningitis combined. Motor vehicle

collision involving car occupants or pedestrians is the most common cause of accidental death in children; drowning, burns, and firearms account for a significant segment of the

remaining group. Not evident in the mortality statistics is the number of children who sustain injury and recover with a subsequent disability. Improved methods of communication,

immediate prehospital care, and rapid transportation to regional centers increase the probability of survival after a major traumatic injury. Because of the complex requirements for

resuscitation and treatment of an injured child, it is essential that each regional referral center establish a systematic approach to care.

Management of trauma in children requires immediate recognition and treatment of life-threatening injuries to the head, thorax, and abdomen. Recognition that the child with severe

head injury manifests a different physiologic response from that of the adult forms the foundation of successful therapy. Aggressive therapy of elevated intracranial pressure results

in improved survival; 30 percent of the childhood victims of serious head trauma die, whereas the remainder make a good to excellent recovery. Thoracic trauma occurs in 5 percent

of all injured children. Blunt abdominal trauma is common in the pediatric population, the spleen and liver are the most frequent intraabdominal organs sustaining injury.

Nonoperative management is a reasonable approach in the child with blunt hepatic or splenic trauma with stable vital signs. Exploratory laparotomy is indicated for a physiologically

unstable child despite appropriate fluid resuscitation. These children should undergo laparotomy for hemostasis, and an attempt at splenic salvage by splenorrhaphy is warranted if

the child's condition permits. Splenic salvage is important in children to minimize the potential for future overwhelming sepsis. Lap belt injuries are increasingly common in children

due to mandatory seat belt laws. Lap-belt injuries may cause serious intestinal trauma and lumbar spine fractures and are poorly diagnosed by the abdominal CT. Peritoneal lavage

or laparotomy is indicated in this group of injured children.

Consideration of the unique requirements of the injured child during evaluation and therapy improves outcome and minimizes mortality. Aerophagia proceeding to gastric dilatation

can compromise respiration or mimic an abdominal injury; therefore, nasogastric decompression is essential in all children with significant injury. The temperature of injured children

might drop precipitously because of the relatively large surface area to body mass ratio. Hypothermia potentiates the deleterious effects of shock and metabolic acidosis.

Hypovolemic shock with attendant cellular hypoperfusion requires treatment by infusion of crystalloid solutions at a rate of 20 mL/kg, I.V. push. Urine output (1mL/kg/h) in children is

a useful indicator of adequate fluid resuscitation. Once initial assessment and resuscitation are complete, diagnostic measures with conventional x-rays and CT scan are important.

Prompt movement to a pediatric intensive care unit is essential unless a decision for operation is necessary. Complete rehabilitation of the child and the family should be the

ultimate goal of every pediatric trauma center. The solution to pediatric trauma is not improved schemes for treatment but rather prevention of injury