133. Doyle NM, Lally KP. The CDH study group and advances in the clinical care of the patient with

congenital diaphragmatic hernia. Semin Perinatol 2004;28(5):174–184.

134. Migliazza L, Bellan C, Alberti D, et al. Retrospective study of 111 cases of congenital diaphragmatic

hernia treated with early high-frequency oscillatory ventilation and presurgical stabilization. J

Pediatr Surg 2007;42:1526–1532.

135. Gosche JR, Islam S, Boulanger SC. Congenital diaphragmatic hernia: searching for answers. Am J

Surg 2005;190:324–332.

136. Vijfhuize S, Schaible T, Kraemer U, et al. Management of pulmonary hypertension in neonates with

congenital diaphragmatic hernia. Eur J Pediatr Surg 2012;22:374–383.

137. Sluiter I, Reiss I, Kraemer U, et al. Vascular abnormalities in human newborns with pulmonary

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hypertension. Expert Rev Respir Med 2011;5(2):245–256.

138. Baird R, MacNab YC, Skarsgard ED, et al. Mortality prediction in congenital diaphragmatic hernia.

J Pediatr Surg 2008;43:783–787.

139. Kasales CJ, Coulson CC, Meilstrup JW, et al. Diagnosis and differentiation of congenital

diaphragmatic hernia from other noncardiac thoracic fetal masses. Am J Perinatol 1998;15(11):623–

628.

140. Shue EH, Miniati D, Lee H. Advances in prenatal diagnosis and treatment of congenital

diaphragmatic hernia. Clin Perinatol 2012;39:289–300.

141. Rashid A, Ivy D. Severe paediatric pulmonary hypertension: new management strategies. Arch Dis

Child 2005;90(1):92–98.

142. Zamora IJ, Olutoye OO, Cass DL, et al. Prenatal MRI fetal lung volumes and percent liver

herniation predict pulmonary morbidity in congenital diaphragmatic hernia (CDH). J Pediatr Surg

2014;49:688–693.

143. Lally KP, Lally PA, Langham MR, et al. Congenital Diaphragmatic Hernia Study Group. Surfactant

does not improve survival rate in preterm infants with congenital diaphragmatic hernia. J Pediatr

Surg 2004;39(6):829–833.

144. Grethel EJ, Cortes RA, Wagner AJ, et al. Prosthetic patches for congenital diaphragmatic hernia

repair: Surgisis vs Gore-Tex. J Pediatr Surg 2006; 41:29–33; discussion 29-33.

145. Rana AR, Khouri JS, Teitelbaum DH, et al. Salvaging the severe congenital diaphragmatic hernia

patient: is a silo the solution? J Pediatr Surg 2008;43(5):788–791.

146. Chan E, Wayne C, Nasr A. Minimally invasive versus open repair of Bochdalek hernia: a metaanalysis. J Pediatr Surg 2014;49:694–699.

147. Chiu PP, Sauer C, Mihailovic A, et al. The price of success in the management of congenital

diaphragmatic hernia: is improved survival accompanied by an increase in long-term morbidity? J

Pediatr Surg 2006;41:888–892.

148. Koivusalo A, Pakarinen M, Vanamo K, et al. Health-related quality of life in adults after repair of

congenital diaphragmatic defects–a questionnaire study. J Pediatr Surg 2005;40:1376–1381.

149. Al-Salem AH. Congenital hernia of Morgagni in infants and children. J Pediatr Surg 2007;42:1539–

1543.

150. Al-Salem AH, Zamakhshary M, Al Mohaidly M, et al. Congenital Morgagni’s hernia: a national

multicenter study. J Pediatr Surg 2014;49:503–507.

151. Laituri CA, Garey CL, Ostlie DJ, et al. Morgagni hernia repair in children: comparison of

laparoscopic and open results. J Laparoendosc Adv Surg Tech A 2011;21(1):89–91.

152. Hu J, Wu Y, Wang J, et al. Thoracoscopic and laparoscopic plication of the hemidiaphragm is

effective in the management of diaphragmatic eventration. Pediatr Surg Int 2014;30:19–24.

153. Ali A, Flageole H. Diaphragmatic pacing for the treatment of congenital central alveolar

hypoventilation syndrome. J Pediatr Surg 2008;43(5):792–796.

154. Krieger LM, Krieger AJ. The intercostal to phrenic nerve transfer: an effective means of

reanimating the diaphragm in patients with high cervical spine injury. Plast Reconstr Surg

2000;105:1255–1261.

155. Jaffe A, Calder AD, Owens CM, et al. Role of routine computed tomography in paediatric pleural

empyema. Thorax 2008;63:897–902.

156. Li ST, Tancredi DJ. Empyema hospitalizations increased in US children despite pneumococcal

conjugate vaccine. Pediatrics 2010;125:26–33.

157. Krenke K, Peradzynska J, Lange J, et al. Local treatment of empyema in children: a systematic

review of randomized controlled trials. Acta Paediatr 2010;99:1449–1453.

158. Avansino JR, Goldman B, Sawin RS, et al. Primary operative versus nonoperative therapy for

pediatric empyema: a meta-analysis. Pediatrics 2005;115(6):1652–1659.

159. Schultz KD, Fan LL, Pinsky J, et al. The changing face of pleural empyemas in children:

epidemiology and management. Pediatrics 2004;113(6):1735–1740.

160. Dotson K, Johnson LH. Pediatric spontaneous pneumothorax. Pediatr Emerg Care 2012;28(7):715–

720; quiz 721-723.

161. Laituri CA, Valusek PA, Rivard DC, et al. The utility of computed tomography in the management

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of patients with spontaneous pneumothorax. J Pediatr Surg 2011;46:1523–1525.

162. Choi SY, Kim YH, Jo KH, et al. Video-assisted thoracoscopic surgery for primary spontaneous

pneumothorax in children. Pediatr Surg Int 2013;29:505–509.

163. Tutor JD. Chylothorax in infants and children. Pediatrics 2014;133:722–733.

164. Haines C, Walsh B, Fletcher M, et al. Chylothorax development in infants and children in the UK.

Arch Dis Child 2014;99:724–730.

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Chapter 103

Pediatric Abdomen

Thomas T. Sato and Marjorie J. Arca

Key Points

1 Gastroschisis occurs with an incidence rate of 1 in 2,000 live births and is characterized by exposed

intestine herniating through a defect to the right of the umbilicus. In contrast, omphalocele is a

midline abdominal wall defect characterized by herniated visceral contents contained within the

umbilical cord covering and has a high incidence rate of associated congenital anomalies.

2 A congenital, indirect inguinal hernia is an abnormal, patent continuation of the peritoneum through

the internal inguinal ring; inguinal hernia repair is the most common elective procedure in pediatric

surgery.

3 Neonatal bilious emesis should be considered the result of an acute mechanical intestinal obstruction

until proven otherwise; emergent surgical evaluation is warranted to determine whether intestinal

malrotation with midgut volvulus is present.

4 Necrotizing enterocolitis (NEC) is a progressive, inflammatory intestinal condition of the surviving

premature neonate. Perforated NEC is the most common neonatal surgical emergency.

5 Hirschsprung disease is caused by aganglionosis of the myenteric nervous system in the rectum.

Most commonly, the rectosigmoid colon is involved, but the length of contiguous aganglionosis

varies in length proximally. Both propulsion and reflexive relaxation may be disordered or absent in

the rectum, leading to functional bowel obstruction in the neonate and chronic constipation in the

older child or adolescent. Enterocolitis associated with Hirschsprung disease is a potentially lifethreatening condition.

6 Intussusception is the invagination or telescoping of a proximal segment of intestine into an adjacent

distal segment and is the most common cause of intestinal obstruction in infants and children 3

months to 3 years of age.

7 The incidence of biliary atresia is 1 in 8,000 to 12,000 live births and is the most common cause of

chronic cholestasis in infants and children as well as the most frequent indication for pediatric liver

transplantation. Early diagnosis and management is necessary for optimal outcome.

ABDOMINAL WALL DEFECTS

Gastroschisis

1 Gastroschisis occurs with an incidence of about 1 in 2,000 to 4,000 live births. Infants with

gastroschisis tend to be born to mothers who are younger (teenage), white, and consumed alcohol or

tobacco during pregnancy.1–3 Familial cases of gastroschisis are distinctly rare.4 Associated congenital

anomalies are uncommon. However, in about 10% of cases, intestinal atresia or stenosis can be seen and

is thought to be a result of mechanical or vascular compromise to the herniated bowel. Rarely, infants

with gastroschisis have complete loss of small bowel secondary to volvulus in utero.

The pathophysiology of gastroschisis remains unknown. In normal fetal development, two umbilical

veins are initially present. As the intestine returns to the abdominal cavity through the umbilicus, the

right umbilical vein undergoes resorption, leaving the left umbilical vein intact. Weakness of the

umbilical membrane at the site of umbilical vein resorption may allow the evisceration of the intestine

through the defect. This explanation is consistent with the clinical observation that the gastroschisis

defect is almost always located to the right of the umbilicus. Routine antenatal ultrasonography has

documented the sequential development of gastroschisis as a consequence of a ruptured hernia of the

umbilical cord in utero.5 Therefore, gastroschisis should be considered an isolated mechanical defect of

the developing umbilical cord rather than a global defect in embryogenesis.

The amount of bowel eviscerated in gastroschisis can be extensive because the bowel has not

2948

undergone complete mesenteric rotation and fixation at this particular time in embryogenesis. The

bowel may be thickened and the mesentery may be foreshortened secondary to the inflammatory

response induced by direct exposure to amniotic fluid. In gastroschisis, herniation of the liver is

distinctly unusual (Fig. 103-1).

Omphalocele

Anatomy, Embryology, and Pathophysiology

The incidence rate of omphalocele is approximately 1 in 6,000 to 10,000 live births and has been stable

over the past several decades. Omphalocele is a midline abdominal wall defect of varying size

characterized by the presence of herniated visceral contents into the translucent sac of the umbilicus.

The sac is composed of amniotic membrane, mesenchymal tissue known as Wharton jelly, and

peritoneum. The umbilical cord attaches to the sac and may be eccentric in origin (Fig. 103-2). The sac

may be inadvertently ruptured before or during delivery but it is always present. Similar to

gastroschisis, intestinal malrotation is usually present. Unlike gastroschisis, the bowel is typically

normal in appearance because it has not been directly exposed to the amniotic fluid. Small omphaloceles

are defined as 2 to 3 cm in diameter and have only a small amount of herniated bowel within the sac.

Closure of small omphaloceles is typically performed without significant physiological complications. In

contrast, giant omphaloceles defined as greater than 4 cm in diameter can lead to extensive herniation

of the stomach, bowel, liver, and spleen with subsequent underdevelopment of the abdominal cavity

(Fig. 103-3).

Omphalocele results from incomplete closure of the anterior abdominal wall at the umbilicus during

embryogenesis. During week 4 of gestation, the midgut undergoes progressive elongation in the yolk

sac outside the embryonic coelomic cavity. The midgut returns to the abdominal cavity during week 10,

where it undergoes normal rotation and fixation of the mesentery to the posterior abdominal wall.

Normal closure of the anterior abdominal wall requires return of the midgut to the abdominal cavity,

along with growth and fusion of the anterior body folds (cephalic, caudal, and two lateral) at the base

of the umbilicus. Failure of growth, migration, or fusion of the lateral body folds leads to omphalocele.

Failure of growth and fusion of the cephalic folds may lead to either a supraumbilical omphalocele

associated with a midline sternal defect (Fig. 103-4) and a herniated heart, termed ectopia cordis, or a

constellation of defects known as the pentalogy of Cantrell.6 This sequence includes a sternal cleft, an

absence of the septum transversum of the diaphragm, a pericardial defect, a cardiac defect, and an

epigastric omphalocele. Infants born with either ectopia cordis or pentalogy of Cantrell have significant

morbidity and often, these conditions are lethal.

Figure 103-1. Gastroschisis. The defect is to the right of the normal umbilicus, and the bowel is thickened and inflamed.

Associated anomalies are more common in infants with omphalocele than with gastroschisis,

reflecting the more global abnormality of embryogenesis in omphalocele. About 50% to 60% of infants

with omphalocele have at least one associated congenital anomaly involving the skeleton,

gastrointestinal tract, nervous system, genitourinary system, and cardiopulmonary system.7,8 In

addition, infants with omphalocele have a higher incidence of chromosomal abnormalities and other

conditions such as Beckwith–Wiedemann syndrome. A comparison of gastroschisis and omphalocele is

summarized in Table 103-1.

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Figure 103-2. Omphalocele. The herniated intestines and liver are visible inside the sac. The umbilical cord attaches to the sac.

Figure 103-3. Ruptured omphalocele. Although the bowel is relatively normal in appearance, the abdominal cavity is extremely

underdeveloped.

Perioperative Management for Gastroschisis and Omphalocele

In contemporary practice, infants with gastroschisis can be safely delivered vaginally.8,9 Studies

comparing vaginal delivery with elective cesarean section for infants with gastroschisis demonstrated no

significant differences in outcome.10,11 Early delivery to minimize intestinal damage in gastroschisis

patients has not been proved to be efficacious.12,13 Fetal well-being has been advocated to be the

primary determinant for gastroschisis. To prevent birth-related hepatic injury, cesarean section is

preferable for prenatally diagnosed infants with giant omphaloceles.

After delivery, infants with either gastroschisis or omphalocele have similar initial management

priorities. If necessary, an adequate airway with effective ventilation and oxygenation is established.

The infant should be maintained under either an external warmer or a humidified incubator. An

orogastric sump tube should be inserted early and placed on suction to prevent further intestinal

distention. In gastroschisis, the herniated viscera should be examined to make certain that the

mesentery is not twisted. In addition, the tightness of the opening of the abdominal wall should be

assessed to ensure that there is sufficient perfusion of the bowel. The viscera should be covered with

gauze plastic wrap to prevent further contamination, hypothermia, and volume depletion. Alternatively,

the infant’s entire lower torso can be placed inside a plastic bowel bag. Regardless of the method, the

initial therapeutic goal is to provide rapid, effective temporary coverage of the viscera. Adequate

support of the herniated viscera must be provided to prevent intestinal ischemia. This can be done by

placing the baby on his or her side, and placing support under the intestines. With large omphaloceles,

the position of the infant’s liver and viscera may impair venous return from the inferior vena cava when

the infant is supine, and these infants may preferentially require a left-side-down position to maintain

normal hemodynamics. Intravenous dextrose and broad-spectrum antibiotics are administered. Infants

with gastroschisis will have higher intravenous fluid requirements to maintain euvolemia. If the infant

is not delivered at a center where definitive surgical care can be provided, urgent transport should be

arranged.

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Figure 103-4. Operative exploration of giant omphalocele with abdominal wall defect, absence of the septum transversum of the

diaphragm, pericardial defect, and cardiac defect.

DIAGNOSIS

Table 103-1 Comparison of Gastroschisis and Omphalocele

Gastroschisis. Once the infant with gastroschisis has been stabilized, measures are taken to secure the

viscera and, if possible, correct the abdominal wall defect. One option is to take the infant to the

operating room, where reduction of the herniated viscera with primary fascial closure of the abdominal

wall is an achievable goal in approximately 60% to 70% of infants with either gastroschisis. Gentle but

definitive stretching of the abdominal wall is performed, and proximal decompression of the bowel is

maintained with orogastric decompression. The defect may need to be enlarged to evaluate the

intestinal tract fully and/or reduce the viscera into the abdominal cavity. The limiting factor in primary

closure of a congenital abdominal wall defect is the increased intra-abdominal pressure generated by the

reduction of the herniated viscera. Increased intra-abdominal pressure can lead to abdominal

compartment syndrome. Features of neonatal abdominal compartment syndrome include impaired

venous return caused by compression of the inferior vena cava, reduction of splanchnic blood flow

leading to mesenteric ischemia, and respiratory compromise secondary to impaired diaphragmatic

excursion. Intraoperative measurement of intragastric or intravesical pressure, end-tidal CO2

, central

venous pressure, or regional oximetry may be helpful in determining the safety of primary abdominal

wall closure. If the herniated viscera cannot be reduced primarily, the viscera is placed in a constructed

Silastic pouch or performed silo. Daily partial reduction of the viscera within the silo is performed. This

technique allows gradual reduction of the herniated viscera into the abdominal cavity, and complete

reduction is usually obtained within 3 to 7 days. The infant is returned to the operating room for

removal of the temporary silo with delayed primary closure of the abdominal wall defect (Fig. 103-5).

Alternatively, a large abdominal wall defect may be effectively covered with abdominal skin flaps, with

delayed repair of the ventral hernia months to years later (gross closure).

In some centers, all babies with gastroschisis are managed by placing a preformed silo at the bedside

after the baby is born. Thereafter, the viscera is slowly reduced into the abdomen and eventual fascial

closure is attained.14 Some studies caution that this practice may lead to longer ventilator and fluid

requirements.14,15 Another method that has been described in gastroschisis patients with noninflamed

pliable intestines is to reduce the viscera with some sedation at the bedside, fold the umbilical cord

stump over the skin closure, and place a pressure dressing over the defect.16 The use of the umbilical

stump has been described even for patients requiring staged or silo closure.17 This method of closure has

been shown to effect fewer days of mechanical ventilation in retrospective studies.17–20

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Omphaloceles. Given the high incidence of associated anomalies, infants with omphalocele should

undergo diagnostic investigation, guided by the clinical presentation and physical examination. These

studies include chest radiography, echocardiogram, and renal ultrasound, in addition to baseline blood

work. Chromosomal analysis may be necessary. Until the decision is made with respect to the timing

and method of repair, the omphalocele should remain covered and protected with a gauze dressing. If

the omphalocele is ruptured or torn, immediate closure or coverage is necessary.

Figure 103-5. Silastic chimney or silo for temporary coverage and staged reduction of giant omphalocele.

Closure of omphaloceles is dictated by the size of the defect, the amount of viscera extruded into the

sac, and the abdominal domain. There is no standard definition of what constitutes a regular versus a

giant omphalocele. Practically, a giant omphalocele has an abdominal wall defect larger than 4 cm,

containing a portion of liver, and is difficult to dose primarily in the first days of life without

physiologic compromise.

Omphaloceles with a small abdominal wall defect typically would have operative fascial closure with

sac excision in the newborn period. Many techniques have been described to close giant omphaloceles

including sac excision and temporary coverage with grafts, use of intraperitoneal tissue expanders,21,22

and allowing the omphalocele sac to scar and then epithelialize in the latter technique.

The sac can be physically supported and left undisturbed, allowing epithelialization of the sac over

several weeks to months. Antibiotic solutions or ointments are usually applied to control

desiccation.22–25 Delayed repair of the ventral hernia is required. This delay is particularly useful in the

infant with a giant omphalocele and a small, underdeveloped abdominal cavity that prohibits primary

closure.

Infants with repaired omphalocele usually have relatively prompt return of bowel function after

definitive repair. In comparison, nearly all infants with gastroschisis have delayed intestinal function

following closure. The use of total parenteral nutrition (TPN) is essential in the treatment of these

infants because it allows nutritional support while the bowel inflammatory process resolves. It is not

unusual for these infants to require up to 4 weeks after repair to have bowel function normalize, and

time taken to achieve full enteral feeding is not affected by the use of erythromycin as a prokinetic

agent.26 Approximately 15% of infants with gastroschisis develop necrotizing enterocolitis (NEC), a

diffuse, often life-threatening inflammatory complication of the neonatal intestinal tract.27 In addition,

infants with gastroschisis are at risk for nutrient malabsorption and intestinal dysmotility with inability

to tolerate full enteral feeding. In particular, infants with gastroschisis and associated intestinal atresia

may have pronounced intestinal dysmotility and may require long-term, sometimes lifelong,

dependence on TPN for caloric intake.28

Long-term outcome of infants operated on for gastroschisis or omphalocele is usually dependent on

the morbidity and mortality of associated conditions rather than the abdominal wall defect itself.

Surgical conditions such as undescended testicles, Meckel diverticulum, and adhesive small bowel

obstruction are encountered with moderate frequency. Adhesive small bowel obstruction most

commonly occurs in the first-year of life and requires operative management in the majority.29 Most

children with repaired abdominal wall defects enjoy satisfactory health and quality of life, although

they have been reported to have a lower degree of physical fitness measured by exercise time and

maximal oxygen consumption.30

Umbilical Hernia

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Anatomy and Embryology

Congenital umbilical hernia is the most common abdominal wall defect in infants and children. The

umbilical ring begins to contract circumferentially after birth and normally is reinforced by the paired

lateral umbilical ligaments (the obliterated umbilical arteries), the singular round ligament (the

obliterated umbilical vein), the urachal remnant, and the transversalis fascia. Incomplete growth or

impaired development of any one of these structures can lead to weakness at the umbilical ring and

cause a congenital umbilical hernia.

Clinical Issues and Management

Congenital umbilical hernias generally do not pose significant problems during childhood. Rarely, an

umbilical hernia presents with incarceration of intra-abdominal contents within the sac.31 Infants and

children may also present with infection or drainage at the umbilicus from associated urachal or

vitelline duct remnants. The incidence rate of congenital umbilical hernia has been reported to be 25%

to 50% in black infants and 4% to 9% in white infants in the first few months of life.32 There is an

increased incidence of umbilical hernia in premature infants, and there is a tendency for familial

inheritance.

Diagnosis of umbilical hernia is usually made after separation of the umbilical cord remnant from the

umbilicus and is often initially noted by parents or pediatrician. The size of the defect may vary from a

few millimeters to several centimeters and is typically reducible and asymptomatic. Age and size of the

defect are the most important factors determining spontaneous closure rates.33 Many umbilical hernias

spontaneously close within the first 2 to 3 years of life. Parents should be reassured that complications

related to untreated umbilical hernia are rare. Given the high rate of spontaneous closure and the

relatively asymptomatic nature of most umbilical hernias, operative repair is generally not performed

during the first 2 years of life. Skin ulceration or an episode of incarceration should prompt earlier

repair. Large defects with significant protrusion may necessitate surgery, and parents may desire repair

if an older child appears to be self-conscious about the hernia.

Nearly all umbilical hernia repairs can be performed as outpatient surgical procedures. An incision is

made along the umbilicus and the hernia sac is dissected free circumferentially. The sac is completely

excised and primary fascial closure is performed. The umbilical skin is typically preserved and sutured

to the fascial closure, and an acceptable cosmetic result is almost always achievable. Large umbilical

hernias with redundant skin may require umbilicoplasty. The incidence of complications such as wound

infection and recurrence is low.

Inguinal Hernia and Hydrocele

Anatomy, Embryology, and Pathophysiology

2 Inguinal hernias constitute one of the major surgical problems of infancy and childhood. Inguinal

hernia repair is the most common elective general surgical procedure performed by pediatric surgeons.

Three distinct anatomic types of inguinal hernias are observed in children: congenital indirect (99% of

infants and children), direct (0.5%), and femoral (<0.5%). An indirect inguinal hernia is an abnormal,

patent continuation of the peritoneum through the internal inguinal ring. The hernia sac originates

lateral to the deep inferior epigastric vessels and descends along the spermatic cord within the

cremasteric fascia. The sac can reside completely within the inguinal canal or descend through the

external inguinal ring into the scrotum. A direct inguinal hernia originates medial to the deep inferior

epigastric vessels and is external to the cremasteric fascia. The hernia sac protrudes directly through the

posterior wall of the inguinal canal and can descend through the external inguinal ring and into the

scrotum. A femoral hernia originates medial to the femoral vein and descends inferior to the inguinal

ligament along the femoral canal. A femoral hernia never enters the scrotum or the labia.

The developing testicle is initially adjacent to the mesonephros and subsequently descends to the

scrotum during the third trimester of gestation. The peritoneal extension that descends alongside the

chorda gubernaculum of the testicle is called the processus vaginalis. A slightly higher incidence rate of

right-sided indirect inguinal hernia is thought to reflect delay of right-sided testicular descent from the

developing inferior vena cava and right external iliac vein. As the testicle descends into the scrotum, the

processus vaginalis forms a serous covering around the testicle known as the tunica vaginalis. Normally,

the patent processus vaginalis undergoes obliteration, closing the communication between the

peritoneal cavity and the inguinal canal. A patent processus vaginalis can lead to a variety of anatomic

conditions of the inguinal region (Fig. 103-6).

The incidence of patent processus vaginalis has been reported to be as high as 80% to 94% in

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newborn infants undergoing autopsy,34 whereas in adulthood, the incidence is 20% to 30%. Infants with

unilateral inguinal hernias have been found to have a patent contralateral processus vaginalis in 60%

during the first few months of life. By the age of 2 years, 20% of these hernias were obliterated, and

half of the remaining 40% became clinical hernias.35 At least 30% of infants requiring placement of a

ventriculoperitoneal shunt for hydrocephalus have been observed to have a patent processus vaginalis in

the first few months of life, with a rapid decline in patency in older children.36 These studies, along

with contemporary use of laparoscopic exploration of the contralateral internal ring, demonstrate that

although a patent processus vaginalis is common in infancy, there is some degree of obliteration that

occurs with increasing age, and a patent processus vaginalis by itself does not constitute a clinical

inguinal hernia.

Figure 103-6. Anatomic variations that occur with different degrees of obliteration of the processus vaginalis. A: Normal;

obliterated processus vaginalis. B: Proximal hernia sac; distal obliterated processus. C: Hernia sac extending into scrotum; no

obliteration. D: Proximal and distal obliteration with hydrocele of the cord. E: Hydrocele of the scrotum, obliterated processus. F:

Patent processus with communicating hydrocele.

Clinical Issues

Inguinal hernias occur in 1% to 3% of all children and in 3% to 5% of premature infants. There is no

known inheritance pattern, but there is an increased incidence of inguinal hernia in children with

connective tissue disorders such as Ehlers–Danlos syndrome and Marfan syndrome. There is a 6:1

predominance of males to females. At least 30% of children are younger than 6 months at the time of

operative repair. Inguinal hernia more commonly presents as right-sided (56.2%) compared with leftsided (27.5%) or bilateral (16.2%).37

Most infants and children have a history of an intermittent inguinal mass or bulge that may descend

into the scrotum or labia. The hernia may become more pronounced during times of increased intraabdominal pressure, such as crying or having a bowel movement. Most inguinal hernias in children

reduce spontaneously or are reducible with gentle, manual pressure along the inguinal canal. Female

infants may have an ovary and fallopian tube in the hernia sac, identified clinically as a firm, slightly

mobile, nontender mass in the labia or the inguinal canal. Most parents or pediatricians give a

2954

characteristic history that is sufficient to warrant inguinal exploration, even in children in whom the

hernia cannot be clinically demonstrated at the time of examination. Depending on institution and

surgeon preference, infants and children with a strong history consistent with inguinal hernia and an

equivocal clinical examination may be offered ultrasound or diagnostic laparoscopy to effectively

confirm the diagnosis before groin exploration.38

Incarceration is a common consequence of untreated inguinal hernia and presents as a nonreducible

mass in the inguinal canal, scrotum, or labia.39 Clinical symptoms and signs are related to the duration

of incarceration. If the incarceration has been present for several hours, the infant may be inconsolable

and have feeding intolerance, pain, abdominal distention, vomiting, and lack of flatus or stool, signaling

complete intestinal obstruction. The affected groin may become quite edematous, and a reactive scrotal

hydrocele may evolve. Elevation of the infant’s lower extremities with a pillow may help encourage

spontaneous reduction. Attempts at manually reducing an incarcerated inguinal hernia should be

performed by an experienced surgeon. If necessary, sedation to calm the infant before attempting

manual reduction may be cautiously used. Ice packs should be avoided in infants and children.

Following successful reduction of an incarcerated hernia, expedient elective repair of the hernia should

be performed after the edema has subsided. If reduction of an incarcerated hernia requires several

attempts and is difficult, overnight inpatient observation is warranted to rule out reduction of

strangulated bowel; fortunately, this is an uncommon occurrence in the pediatric population. Inability to

reduce an incarcerated hernia is a clear indication for urgent operative exploration and repair.

Incarcerated inguinal hernia must be differentiated from an acute, noncommunicating hydrocele, or

inguinal lymphadenitis. With acute hydrocele, it is usually possible to transilluminate the hydrocele and

palpate normal cord structures above the scrotal mass. In addition, symptoms of bowel obstruction are

absent with acute hydrocele. Acute lymphadenitis typically is associated with fever, erythema, and

tenderness, and there may be a history of lower-extremity infection on the ipsilateral side. If the

inguinal mass is not reducible and an incarcerated hernia cannot be excluded, urgent groin exploration

is required.

Operative Considerations and Outcome

The diagnosis of inguinal hernia in an infant or a child is an indication for operative repair. The

rationale for elective repair is to prevent the complications associated with incarceration. At least 71%

of infants who require operative reduction of incarcerated inguinal hernia are younger than 11

months.40 Therefore, an approach emphasizing timely elective repair of inguinal hernia is warranted,

particularly during infancy. Delay of elective repair may be necessary in premature, extremely low–

birth-weight (<1,500 g) infants and in children with other conditions such as congenital heart disease,

pulmonary disease, infection, or metabolic disease.

Elective inguinal hernia repair in the pediatric age group is usually performed as an outpatient

surgical procedure using general anesthesia, although spinal anesthesia is an effective alternative in

selected high-risk infants.41 A regional caudal block or local inguinal nerve block using local anesthetic

is useful to diminish perioperative pain and increase patient comfort. These techniques, along with the

use of rapid-acting general anesthetics, allow the vast majority of children to be discharged home within

hours of operation. Overnight observation and monitoring are required for high-risk infants and

children with disorders that increase anesthetic risk for postoperative apnea.

Repair of pediatric inguinal hernia relies on high ligation of the hernia sac at the internal inguinal

ring. Sensory nerves deep to the external oblique aponeurosis should be identified and preserved.

Careful identification and dissection of the hernia sac from the vas deferens and the testicular blood

supply must be performed. The vas deferens must be carefully dissected free from the sac, and direct

handling or pinching of the vas with forceps is avoided. The absence of a vas deferens or a blind-ending

vas may be observed in children with cystic fibrosis (CF). In female infants, opening the hernia sac to

visualize the ovary and fallopian tube may help avoid inadvertent injury to these structures during

suture ligation of the sac. The distal component of the hernia sac is opened widely, and any fluid in the

sac is evacuated. If the internal inguinal ring is attenuated or enlarged, it can be repaired with a few

sutures. Experience with laparoscopic inguinal hernia repair using purse–string suture closure of the

patent internal ring without direct inguinal exploration has been described.42 The testicle is returned to

its scrotal position by gentle traction on the gubernaculum, and the spermatic cord is carefully aligned

along the inguinal canal. Postoperative pain is managed with oral acetaminophen for 24 to 48 hours;

older children may require postoperative narcotics. In addition, abnormalities of the vas deferens may

be associated with genitourinary anomalies. A renal ultrasound should be permed to rule out kidney

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