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I. INTRODUCTION A. Neonatal Physiologic Characteristics ---1. Water Metabolism ---2. Fluid and Electrolytes Concepts B. Variations in Individual Newborns ---1. Types of Newborns Infants ---2. Metabolic and Host Defenses ---3. Surgical Response of Newborns	II. HEAD AND NECK LESIONS A. Cervical Lymphadenopathy B. Congenital Torticollis C. Thyroglossal Duct Cyst D. Branchial Cleft Fistula E. Cystic Hygromas
III. OBSTRUCTIVE PROBLEMS Neonatal Intestinal Obstruction Logical Approach A. Esophageal Atresia B. Gastro-Duodenal Anomalies ---1. Gastric Anomalies ---2. Pyloric Stenosis ---3. Duodenal Malformations C. Malrotation and Volvulus D. Intestinal Atresia E. Meconium Ileus F. Hirschsprung's disease ---1. Total Colonic Aganglionosis G. Imperforate Anus H. Duplications I. Intussusception J. Appendicitis K. Chronic Intestinal Pseudo-obstruction L. Bezoars M. Neuronal Intestinal Dysplasia	IV. HERNIAS AND ABDOMINAL WALL DEFECT A. Diaphragmatic Hernias ---1. Congenital Diaphragmatic Hernia (Bochdalek) ---2. Morgagni Hernia ---3. Esophageal Hernias B. Processus Vaginalis Remnants ---1. Inguinal Hernias ---2. Hydroceles C. Undescended Testis D. Umbilical hernias E. Omphalocele F. Gastroschisis
V. GASTROINTESTINAL BLEEDING A. Upper GI bleeding (Newborn) B. Lower GI bleeding (Newborn) ---1. Necrotizing Enterocolitis (NEC) C. Upper GI bleeding (Older child) D. Lower GI bleeding (Older child) ---1- Anal Fissure ---2- Meckel's Diverticulum ---3- Juvenile Polyps	VI. PANCREATIC AND BILIARY DISORDERS A. Pancreatitis B. Biliary Atresia C. Choledochal Cyst D. Cholelithiasis E. Idiopathic Perforation Bile Ducts
VII. TUMORS A. Wilms tumor & Genetics  B. Neuroblastoma & Genetics C. Rhabdomyosarcoma & Genetics D. Liver Tumors E. Sacrococcygeal Teratoma F. Ovarian Tumors G. Thyroid Nodules H. Burkitt's Lymphoma	VIII. GYNECOLOGIC CONSIDERATIONS A. Labial Adhesions in Infants B. Ovarian Cyst C. Breast Disorders
IX. PRENATAL CONGENITAL MALFORMATIONS A. Fetal Surgery B. Fetal Intestinal Obstruction C. Prenatal CCAM	X. PEDIATRIC LAPAROSCOPY A. Physiology of the Pneumoperitoneum B. Laparoscopic Cholecystectomy C. Laparoscopic Appendectomy D. Laparoscopy for the Undescended Testis E. Groin Laparoscopy F. Laparocopic Splenectomy G. Laparoscopic Fundoplication
XI. SUGGESTED READING A. Specific Reading B. General Reading

Created: March 1996
 Last updated: May 2008

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I. INTRODUCTION

A. Neonatal Physiologic Characteristics

1. Water metabolism

Water represents 70 to 80% of the body weight of the normal neonate and premature baby respectively. Total body water (TBW) varies inversely with fat content, and prematures have less fat deposits. TBW is distributed into extracellular fluid (ECF) and intracellular fluid (ICF) compartment. The ECF compartment is one-third the TBW with sodium as principal cation, and chloride and bicarbonate as anions. The ICF compartment is two-third the TBW with potassium the principal cation. The Newborn's metabolic rate is high and extra energy is needed for maintenance of body temperature and growth. A change in body water occurs upon entrance of the fetus to his new extrauterine existence. There is a gradual decrease in body water and the extracellular fluid compartment with a concomitant increase in the intracellular fluid compartment. This shift is interrupted with a premature birth. The newborn's body surface area is relatively much greater than the adults and heat loss is a major factor. Insensible water loss are from the lung (1/3) and skin (2/3). Transepithelial (skin) water is the major component and decreases with increase in post-natal age. Insensible water loss is affected by gestational age, body temperature (radiant warmers), and phototherapy. Neonatal renal function is generally adequate to meet the needs of the normal full-term infant but may be limited during periods of stress. Renal characteristics of newborns are a low glomerular filtration rate and concentration ability (limited urea in medullary interticium) which makes them less tolerant to dehydration. The neonate is metabolically active and production of solute to excrete in the urine is high. The kidney in the newborn can only concentrate to about 400 mOsm/L initially (500-600 mOsm/L the full-term compared to 1200 mOsm/L for an adult), and therefore requires 2-4 cc/kg/hr urine production to clear the renal solute load. The older child needs about 1-2 cc/kg/hr and the adult 0.5-1 cc/kg/hr.

2. Fluid and Electrolytes Concepts

Cellular energy mediated active transport of electrolytes along membranes is the most important mechanism of achieving and maintaining normal volume and composition of fluid compartments. Infants can retain sodium but cannot excrete excessive sodium. Electrolytes requirements of the full-term neonate are: Sodium 2-3 meq/kg/day, potassium 1-2 meq/kg/day, chloride 3-5 meq/kg/day at a rate of fluid of 100cc/kg/24 hrs for the first 10 kg of weight. As a rule of thumb, the daily fluid requirements can be approximated too:

prematures 120-150cc/kg/24 hrs

neonates (term) 100cc/kg/24 hrs

Infants >10kg 1000cc+ 50cc/kg/24 hrs.

Special need of preterm babies fluid therapy are: conservative approach, consider body weight changes, sodium balance and ECF tonicity. They are susceptible to both sodium loss and sodium and volume overloading. High intravenous therapy can lead to patent PDA, bronchopulmonary dysplasia, enterocolitis and intraventricular hemorrhage. Impaired ability to excrete a sodium load that can be amplify with surgical stress (progressive renal retention of sodium). Estimations of daily fluid requirements should take into consideration:

(1) urinary water losses,

(2) gastrointestinal losses,

(3) insensible water losses, and

(4) surgical losses (drains).

Blood Volumes estimates of help during surgical blood loss are:

premature 85-100 cc/kg,

term 85 cc/kg,

and infant 70-80 cc/kg.

The degree of dehydration can be measured by clinical parameters such as: body weight, tissue turgor, state of peripheral circulation, depression of fontanelle, dryness of the mouth and urine output. Intravenous nutrition is one of the major advances in neonatal surgery and will be required when it is obvious that the period of starvation will go beyond five days. Oral feeding is the best method and breast is best source. Newborn infants requires 100-200 calories/kg/day for normal growth. This is increased during stress, cold, infection, surgery and trauma. Minimum daily requirement are 2-3 gm/kg of protein, 10-15 gm/kg of carbohydrate and small amount of essential fatty acids.

B. Variations in Individual Newborns

1. Types of Newborns Infants

a) The full-term, full-size infant with a gestational age of 38 weeks and a body weight greater than 2500 grams (TAGA)- they received adequate intrauterine nutrition, passed all fetal tasks and their physiologic functions are predictable.

b) The preterm infant with a gestational age below 38 weeks and a birth weight appropriate for that age (PreTAGA);

c) The small-for-gestational-age infant (SGA) with a gestational age over 38 weeks and a body weight below 2500 grams- has suffered growth retardation in utero.

d) A combination of (b) and (c), i.e., the preterm infant who is also small for gestational age.

The characteristic that most significantly affects the survival of the preterm infant is the immature state of the respiratory system. Between 27 and 28 weeks of gestation (900-1000 grams), anatomic lung development has progressed to the extent that extrauterine survival is possible. It is only after 30 to 32 weeks of gestation that true alveoli are present. Once there is adequate lung tissue, the critical factor that decides extrauterine adaptation and survival of the preterm infant is his capabilities to produce the phospholipid-rich material, surfactant that lines the respiratory epithelium.

2. Metabolic and Host Defenses

Handling of the breakdown products of hemoglobin is also a difficult task for the premature infant. The ability of the immature liver to conjugate bilirubin is reduced, the life span of the red blood cell is short, and the bilirubin load presented to the circulation via the enterohepatic route is increased. "Physiologic" jaundice is, therefore, higher in the preterm infant and persists for a longer period. Unfortunately, the immature brain has an increased susceptibility to the neurotoxic effects of high levels of unconjugated bilirubin, and kernicterus can develop in the preterm baby at a relatively low level of bilirubin. Other problems affecting the baby include the rapid development of hypoglycemia (35 mg%), hypocalcemia and hypothermia. Newborns have a poorly developed gluconeogenesis system, and depends on glycolysis from liver glycogen stores (depleted 2-3 hrs after birth) and enteral nutrition. Immature infants can develop hyperglycemia from reduced insulin response to glucose causing intraventricular hemorrhage and glycosuria. The preterm and surgical neonate is more prone to hypocalcemia due to reduced stores, renal immaturity, and relative hypoparathyroidism (high fetal calcium levels). Symptoms are jitteriness and seizures with increase muscle tone. Calcium maintenance is 50 mg/kg/day. Human beings are homeothermic organisms because of thermoregulation. This equilibrium is maintained by a delicate balance between heat produced and heal lost. Heat production mechanisms are: voluntary muscle activity increasing metabolic demands, involuntary muscle activity (shivering) and non-shivering (metabolizing brown fat). Heat loss occurs from heat flow from center of the body to the surface and from the surface to the environment by evaporation, conduction, convection and radiation. There is an association between hypothermia and mortality in the NICU's. The surgical neonate is prone to hypothermia. Infant produce heat by increasing metabolic activity and using brown fat. Below the 35°C the newborn experiences lassitude, depressed respiration, bradycardia, metabolic acidosis, hypoglycemia, hyperkalemia, elevated BUN and oliguria (neonatal cold injury syndrome). Factors that precipitate further these problems are: prematurity, prolonged surgery, and eviscerated bowel (gastroschisis). Practical considerations to maintain temperature control are the use of humidified and heated inhalant gases during anesthesia, and during all NICU procedures use radiant heater with skin thermistor-activated servo-control mechanism. The newborn's host defenses against infection are generally sufficient to meet the challenge of most moderate bacterial insults, but may not be able to meet a major insult. Total complement activity is 50% of adults levels. C3,C4,C5 complex, factor B, and properdin concentration are also low in comparison to the adult. IgM, since it does not pass the placenta, is absent.

3- Surgical Response of Newborns

The endocrine and metabolic response to surgical stress in newborns (NB) is characterized by catabolic metabolism. An initial elevation in cathecolamines, cortisol and endorphins upon stimulation by noxious stimuli occurs; a defense mechanism of the organism to mobilize stored energy reserves, form new ones and start cellular catabolism. Cortisol circadian responsiveness during the first week of life is diminished, due to inmaturation of the adrenal gland. Cortisol is responsible for protein breakdown, release of gluconeogenic aminoacids from muscle, and fat lipolysis with release of fatty acids. Glucagon secretion is increased. Plasma insulin increase is a reflex to the hyperglycemic effect, although a resistance to its anabolic function is present. During surgical stress NB release glucose, fatty acids, ketone bodies, and amino acids; necessary to meet body energy needs in time of increase metabolic demands. Early postoperative parenteral nutrition can result in significant rate of weight gain due to solid tissue and water accumulation. Factors correlating with a prolonged catabolic response during surgery are: the degree of neuroendocrinological maturation, duration of operation, amount of blood loss, type of surgical procedure, extent of surgical trauma, and associated conditions (hypothermia, prematurity, etc.). They could be detrimental due to the NB limited reserves of nutrients, the high metabolic demands impose by growth, organ maturation and adaptation after birth. Anesthetics such as halothane and fentanyl can suppress such response in NB.

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II. NECK LESIONS

A. Cervical Lymphadenopathy

An enlarged lymph node is the most common neck mass in children. Most are anterior to the sternocleidomastoid muscle. Infection is the usual cause of enlargement; viral etiology and persist for months. Acute suppurative submandibular adenitis occur in early childhood (6 mo-3 yrs), is preceded by pharyngitis or URI, the child develops erythema, swelling and cellulitis, and management is antibiotics and drainage. Chronic adenitis: persistent node (> 3 wk., tonsillar), solitary, non-tender, mobile and soft. Generally no tx if < 1 cm, for nodes above 2 cm sizes with rapid growth, clustered, hard or matted do biopsy. Other causes are: (1) Mycobacterial adenitis- atypical (MAIS complex), swollen, non-tender, nor-inflamed, positive skin test, excision is curative, chemotx is of no value. (2) Cat-Scratch adenitis- caused by A. Fellis, transmitted by kittens, positive complement fixation test, minimally tender, fluctuant regional nodes, spontaneous resolution. (3) Hodgkin's disease mostly teenager and young adults, continuing growth, non-tender node, associated to weight loss, biopsy is diagnostic.

B. Congenital Torticollis

Congenital muscular torticollis is a disorder characterize by shortening of the cervical muscles, most commonly the sternocleidomastoid (SCM) muscle, and tilting of the head to the opposite side. This is the result of endomysial fibrosis of the SCM muscle. There is a relationship between birth position and the side affected by the contracture. Congenital torticollis causes: plagiocephaly (a craniofacial deformity), fascial asymmetry (hemihypoplasia), scoliosis and atrophy of the ipsilateral trapezius muscle if not corrected. Torticollis can develop at any age, although is more common during the first six months of life. The SCM muscle can be a fibrous mass, or a palpable tumor 1-3 cm in diameter within the substance of the muscle is identified by two to three weeks of age. Management is conservative in most cases using early physiotherapy exercises' a mean duration of three months to achieve full passive neck range of motion. The severity of restriction of motion is the strongest predictor of treatment duration. Those children with failed medical therapy or the development of fascial hemihypoplasia should undergo surgical transection of the SCM muscle.

C. Thyroglossal Duct Cysts

Thyroglossal duct cyst (TDC) is the most common congenital anterior midline neck mass usually (2/3 of cases) presenting before the second decade of life. Symptoms appear at an average age of four with the sudden appearance of a cystic mass at the angle of neck level moving with tongue protrusion and swallowing. Males are more commonly affected than females. TDC is an embryologic anomaly arising from epithelial remnant left after descent of the developing thyroid from the foramen cecum. The lining is cuboidal, columnar or pseudostratified epithelium. TDC is associated to discomfort, infection and a slight probability of malignancy. A legally protective requirement is to document that the mass is not ectopic thyroid gland. Diagnosis is physical. Sonograms will show a cyst between 0.4 and 4 cm in diameter, with variable sonographic appearance and no correlation with pathological findings of infection or inflammation. Once infected surgical excision is more difficult and recurrence will increase. Management is Sistrunk's operation: Excision of cyst with resection of duct along with the central portion of hyoid bone (a minimum of 10-15 mm of hyoid bone should be removed) and some muscle surrounding the proximal ductules (the length of single duct above the hyoid bone spreads into many ductuli as it approach the foramen cecum). Extensive dissection can cause pharyngodynia. The greatest opportunity for cure is surgery at initial non-inflamed presentation. Inadequate excision is a risk factor for further recurrence.

D. Branchial Cleft Fistulas

Branchial cleft fistulas (BCF) originate from the 1st to 3rd branchial apparatus during embryogenesis of the head and neck. Anomalies of the 2nd branchial cleft are by far the most commonly found. They can be a cyst, a sinus tract or fistulas. Fistulas (or sinus tract if they end blindly) display themselves as small cutaneous opening along the anterior lower third border of the sternocleidomastoid muscle, communicates proximally with the tonsillar fossae, and can drain saliva or a mucoid secretion. Management consists of excision since inefficient drainage may lead to infection. I have found that dissection along the tract (up to the tonsillar fossa!) can be safely and easily accomplished after probing the tract with a small guide wire in-place. This will prevent injury to nerves, vessels and accomplish a pleasantly smaller scar. Occasionally a second stepladder incision in the neck will be required. 1st BCF are uncommon, located at the angle of the mandible, and communicating with the external auditory canal. They have a close association with the fascial nerve. 3rd BCF are very rare, run into the piriform sinus and may be a cause of acute thyroiditis or recurrent neck infections.

E. Cystic Hygroma

Cystic hygroma (CH) is an uncommon congenital lesion of the lymphatic system appearing as a multilocular fluid filled cavity most commonly in the back neck region, occasionally associated with extensive involvement of airway or vital structures. The etiology is intrauterine failure of lymphatics to communicate with the venous system. Prenatal diagnosis can be done during the first trimester of pregnancy as a huge neck tumor. Differential diagnosis includes teratomas, encephalocele, hemangiomas, etc. There is a strong correlation between prenatal dx and Turner's syndrome (> 50%), structural defects (Noonan's syndrome) and chromosomic anomalies (13, 18, 21). Early diagnosis (< 30 wk gestation) is commonly associated to those anomalies, non-immune hydrops and dismal outcome (fetal death). Spontaneous regression is less likely but can explain webbed neck of Turner and Noonan's children. Prenatal dx should be followed by cytogenetic analysis: chorionic villous sampling, amniocentesis, or nuchal fluid cell obtained from the CH itself to determine fetal karyotype and provide counseling of pregnancy. Late diagnosis (>30 wks) should be delivered in tertiary center prepare to deal with dystocia and postnatal dyspnea of newborn. The airway should be secured before cord clamping in huge lesions. Intracystic injection of OK432 (lyophilized product of Streptococcus pyogenes) caused cystic (hygromas) lymphangiomas to become inflamed and led to subsequent cure of the lesion without side effects.

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III. OBSTRUCTIVE PROBLEMS

Signs and Symptoms
   1. Bilious vomiting is always abnormal.
   2. Abdominal distention (scaphoid abdomen possible).
   3. Delayed, scanty or no passage of meconium.
   4. Polyhydramnios in mother.
   5. Down's syndrome
   6. Family history
        a. Hirschsprung's disease
        b. Diabetic mother
        c. Jejunal atresia

Work-up (Logical approach)
1. While the infant is being studied, it must be kept in mind that the problem may be "non-surgical".
     a. Sepsis of the newborn with associated ileus is the most important cause of non-surgical bilious vomiting and abdominal distention.
     b. Intracranial lesions
             i. Hydrocephalus
             ii. Subdural hemorrhage
     c. Renal disease associated with uremia.
             i. Renal agenesis
             ii. Polycystic disease
             iii. Other urinary tract anomalies which may be associated with severe hydronephrosis.

2. Plain roentgenograms of the abdomen.
    a. Diagnostic in complete high intestinal obstruction- no gas in distal small bowel.
        i. Double bubble in duodenal obstruction.
        ii. Few gas filled loops beyond duodenum indicates jejunal atresia.
    b. Many gas filled loops (requires 24 hours) indicates some form of low intestinal obstruction.
        i. Ileal atresia
        ii. Meconium ileus (an unfortunate misnomer)- obstruction of the distal small intestine by thick undigested meconium.
        iii. Meconium plug syndrome - obstruction of colon by a plug of meconium.
        iv. Small left colon syndrome.
        v. Hirschsprung's disease - congenital aganglionosis of colon starting with the rectum.
        vi. Colonic atresia.
    c. May be nonspecific in instances of malrotation of the intestines.  This diagnosis must always be considered in neonates with unexplained bilious vomiting.
    d. Calcifications - at some time during fetal life meconium was (is) present in the abdomen.

3. Contrast enema will differentiate the various types of low intestinal obstruction.
    a. Microcolon - complete obstruction of the small bowel.
    b. Meconium plug syndrome - colon dilated proximal to an intraluminal mass.
    c. Hirschsprung's disease - although it may appear to be diagnostic, not reliable in the newborn.
    d. Small left colon syndrome - colon dilated to the splenic flexure, then becomes narrow.

4. Upper G.I. series - the procedure of choice in diagnosing malrotation of the intestines. In the past a contrast enema was thought to be the diagnostic test of choice in instances of malrotation but the cecum and ascending colon can be in normal position in an infant or child with malrotation of the intestines.

5. Rectal biopsy - a pathologist competent in reading the slides is essential and should not be taken for granted.
    a. Suction biopsy of the rectal mucosa and submucosa- best screening procedure to rule out Hirschsprung's disease (ganglion cells are present in the submucosa), and is diagnostic in experienced hands.
    b. Full thickness biopsy of the rectal wall may be necessary if the suction biopsy is non-diagnostic or if the pathologist is unwilling or unable to make the diagnosis of aganglionosis on a suction biopsy specimen. This procedure is difficult in the small infant and has been replaced by the suction biopsy in most centers.
    c. All newborns who have delayed passage of meconium associated with a suspicious contrast enema should have a suction biopsy of the rectal mucosa and submucosa. With this technique, Hirschsprung's disease will be diagnosed early before it is complicated with enterocolitis. If delayed passage of meconium is "cured" by rectal stimulation(suppository, thermometer, or finger), it must be kept in mind that the diagnosis of Hirschsprung's disease is still a possibility. Whether or not a suction biopsy of the rectum is done before the infant goes home depends on the clinical setting but the safe course of action is to do the rectal biopsy before discharge. Parents may not call before the infant gets into trouble with enterocolitis.
    d. Suction biopsy of the rectum is probably indicated in all cases of so called meconium plug syndrome or small left colon syndrome. If the suction biopsy is not done, the infant must be observed for recurrent gastrointestinal symptoms. A breast-fed infant who has Hirschsprung's disease can "get by" for a prolonged period of time.

6. Concluding comments:
    The newborn suspected of having intestinal obstruction should be studied in a logical step by step manner. It is important that it be definitely established that the infant has a surgical problem before surgery is performed. This is usually not difficult in instances of complete high small bowel obstruction or when plain films of the abdomen show calcification and/or a distal small bowel obstruction with the contrast enema showing a microcolon or a definite malrotation of the colon (cecum in upper mid-abdomen or left upper quadrant).
    When plain films are suggestive of a high small bowel obstruction but there is gas in the distal small bowel, an upper GI series rather than a contrast enema should be performed. It is critically important that the diagnosis of malrotation of the intestines be always considered and ruled out in a neonate with bilious vomiting. Prompt recognition and treatment of malrotation of the intestines which is often associated with a midgut volvulus avoids the dire consequences of the problems associated with a massive small bowel resection.
    Mistakes are frequently made when the contrast enema is interpreted as normal, meconium plug syndrome, small left colon syndrome or Hirschsprung's disease. In all of  these clinical situations, a suction biopsy of the rectum is an excellent screening  procedure. If ganglion cells are present, Hirschsprung's disease is ruled out and the infant probably has a non-surgical diagnosis.  If ganglion cells are absent, the next step depends on the clinical picture and setting. If the pathologist is experienced and confident of the interpretation, the diagnosis of Hirschsprung's disease can be made with confidence. If there is any doubt about the absence of ganglion cells in the suction biopsy, a full thickness biopsy of the rectum (a difficult technical procedure requiring a general anesthetic) can be done to settle the issue. If Hirschsprung's disease is believed to be the problem, it must be diagnosed histologically before the infant is operated upon because at the time of surgery the site of obstruction may not be apparent and the abdomen may be closed because no obvious site of obstruction is found.
    Hypothyroidism in the first two to three months of life can mimic Hirschsprung's disease in all aspects except for a normal rectal biopsy.
    Another important point to remember is that duodenal atresia is a different disease from jejunal or ileal atresia in terms of their cause. Jejunal and ileal atresia occur as a result of a vascular accident in the small bowel mesentery during fetal life. Consequently, there is a relatively low incidence of other congenital anomalies except for cystic fibrosis.
    Duodenal atresia is a different disease in that there is a very high incidence of associated anomalies-- (Down's syndrome, imperforate anus, renal anomalies, congenital heart disease, etc.).
    Malrotation of the intestines and Hirschsprung’s disease must be ruled out before a newborn with unexplained bilious vomiting and/or abdominal distention is sent home. It can be unsafe to rely on parents to observe their infant for problems resulting from the above conditions. If diagnosed late, malrotation of the intestines or Hirschsprung’s disease can become life threatening or result in life long problems.

Esophageal atresia (EA) with distal tracheo-esophageal fistula (TEF) is the most common congenital
anomaly of the esophagus, followed by EA without TEF also known as pure esophageal atresia and
pure TEF. Incidence is one in every 2500 live births. The trachea and esophagus initially begin as a ventral diverticulum of the foregut during the third intrauterine week of life. A proliferation of endodermal cells appears on the lateral aspect of this growing diverticulum. These cell masses will divide the foregut into trachea and esophageal tubes. Whether interruption of this normal event leads to tracheo-esophageal anomalies, or during tracheal growth atresia of the esophagus results because of fistulous fixation of the esophagus to the trachea remians to be proven. Polyhydramnios is most commonly seen in pure EA. EA causes excessive salivation, choking, coughing, regurgitation with first feed and inability to pass a feeding tube into the stomach. Contrast studies are rarely needed and of potential disaster (aspiration). Correct dehydration, acid-base disturbances, respiratory distress and decompress proximal esophageal pouch (Reploge tube). Evaluate for associated conditions such as VACTERL association. Correct dehydration, acid-base disturbances, respiratory distress and decompress proximal esophageal pouch (Reploge tube). Evaluate for associated conditions such as VACTERL association (3 or more):
 -Vertebral anomalies i.e. hemivertebrae, spina bifida
 -Anal malformations i.e. imperforate anus
 -Cardiac malformations i.e. VSD, ASD, Tetralogy Fallot
 -Tracheo-Esophageal fistula (must be one of the associated conditions)
 -Renal deformities i.e. absent kidney, hypospadia, etc.
 -Limb dysplasia
    Early surgical repair (transpleural or extrapleural) is undertaken for those babies with adequate arterial blood gases, adequate weight (>1200 gm) and no significant associated anomalies. Delayed repair (gastrostomy first) for all other patients. Repair consists of muscle-sparing thoracotomy, closure of TEF and primary anastomosis. Esophagogram is done 7-10 days after repair. Most important predictors of outcome: birth weight, severity of pulmonary dysfuntion, and presence of major congenital cardiac disease. Complications after surgery: anastomotic leak, stricture, gastroesophageal reflux, tracheomalacia and recurrent TEF. Increase survival is associated with improvements in perioperative care, meticulous surgical technique and aggressive treatment of associated anomalies.
    Congenital isolated tracheo-esophageal fistula (TEF) occurs as 4-6% of the disorders of the esophagus bringing problems during early diagnosis and management. More than H-type is N-type, due to the obliquity of the fistula from trachea (carina or main bronchi) to esophageal side (see the figure) anatomically at the level of the neck root (C7-T1). Pressure changes between both structure can cause entrance of air into the esophagus, or esophageal content into the trachea. Thus, the clinical manifestation that we must be aware for early diagnosis are: cyanosis, coughing and choking with feedings, recurrent chest infections, persistent gastrointestinal distension with air, and hypersalivation. Diagnosis is confirmed with a well-done esophagogram, or video-esophagogram (high success rates, establish level of the TEF). Barium in the trachea could be caused by aspiration during the procedure. Upon radiologic doubt bronchoscopy should be the next diagnostic step. Any delay in surgery is generally due to delay in diagnosis rather than delay in presentation. Management consists of surgical closure of the TEF through a right cervical approach. Hint: a small guide-wire threaded through the fistula during bronchoscopy may be of some help. Working in the tracheo-esophageal groove can cause injury to the recurrent laryngeal nerve with vocal cord paralysis. Recurrence after closure is rare.aggressive treatment of associated anomalies.
    The three most common anastomotic complications are in order of frequency: stricture, leakage and recurrent TEF. Recurrent TEF after surgical repair for esophageal atresia occurs in approximately 3-15% of cases. Tension on the anastomoses followed by leakage may lead to local inflammation with breakage of both suture lines enhancing the chance of recurrent TEF. Once established, the fistula allows saliva and food into the trachea, hence clinical suspicion of this diagnosis arises with recurrent respiratory symptoms associated with feedings after repair of esophageal atresia. Diagnosis is confirmed with cineradiography of the esophagus or bronchoscopy. A second thoracotomy is very hazardous, but has proved to be the most effective method to close the recurrent TEF. Either a pleural or pericardial flap will effectively isolate the suture line. Pericardial flap is easier to mobilize, provides sufficient tissue to use and serves as template for ingrowth of new mucosa should leakage occur. Other alternatives are endoscopic diathermy obliteration, laser coagulation, or fibrin glue deposition.

B. Gastro-Duodenal Anomalies

B.1 Gastric Anomalies

Congenital gastric outlet obstruction is extremely rare. It occurs either in the pyloric or antral region. Antral membranes (web or diaphragm) are thin, soft and pliable, composed of mucosa/submucosa, and located eccentric 1-3 cm proximal to pyloro-duodenal junction. They probably represent the developmental product of excess local endodermal proliferation and redundancy. The diagnosis should rely on history, contrast roentgenology studies and endoscopic findings. Symptoms are those of recurrent non-bilious vomiting and vary according to the diameter of aperture of the membrane. There is a slight male predominance with fair distribution between age groups in children. Associated conditions: pyloric stenosis, peptic ulcer and cardiac. History of polyhydramnios in the mother. Demonstration of a radioluscent line perpendicular to the long axis of the antrum is diagnostic of a web. Endoscopy corroborates the diagnosis. Management can be either surgical or non-surgical. Surgical Tx is successful in symptomatic pt. and consist of pyloroplasty with incision or excision of the membrane. Other alternative is endoscopic balloon dilatation or transection of the web. Non-obtructive webs found incidentally can be managed medically with small curd formula and antispasmodics. The presence of an abnormally dilated gastric bubble in prenatal sonography should alert the physician toward the diagnosis of congenital antro-pyloric obstruction.

B.2 Pyloric Stenosis

Is an abnormality of the pyloric musculature (hypertrophy) causing gastric outlet obstruction in early infancy. The incidence is 3 per 1000 live births. The etiology is unknown, but pylorospasm to formula protein cause a work hypertrophy of the muscle. Diagnostic characteristics are: non-bilious projectile vomiting classically 3-6 weeks of age, palpable pyloric muscle "olive", contrast studies are not necessary when the pyloric muscle is palpated, enlarged width and length in ultrasonography.  The treatment consist in correction of hypochloremic alkalosis and state of dehydration and performing a Fredet-Ramstedt modified pyloromyotomy. Post-operative management consist of: 50% will have one to several episodes of vomiting, usually can feed and go home in 24-36 hours, initial feeds start 8-12 hours after surgery.

B.3 Duodenal Malformations

Can be intrinsic (Atresia, Stenosis, Webs) or extrinsic (Annular pancreas, Ladd's bands). Occur distal or proximal to the ampulla of Vater. Most commonly distal to ampulla and therefore bilious vomiting is present. (Note: Bilious vomiting is surgical until proven otherwise in a baby).
 "Windsock" webs have clinical importance because of their tendency to be confused with distal duodenal obstruction and because of the frequent occurrence of an anomalous biliary duct entering along their medial margin.  Embryology: The first major event in the differentiation of the duodenum, hepatobiliary tree, and pancreas occurs at about the third week in gestation, when the biliary and pancreatic buds form at the junction of the foregut and the midgut. The duodenum at this time is a solid cord of epithelium, which undergoes vacuolization followed by recanalization and restitution of the intestinal lumen over 3-4 weeks of normal development. Failure of recanalization of the second part of the duodenum results in congenital obstruction of the lumen, often in conjunction with developmental malformation of the pancreatic anlagen and the terminal part of the biliary tree. In support of this concept is the high incidence of annular pancreas observed, believed to represent a persistence of the ventral pancreatic anlage in association with intrinsic duodenal obstruction.
Congenital partial obstruction of the duodenum can be either intrinsic (membrane, web or pure) or
extrinsic (Ladd's bands, annular pancreas). A significant group (25-33%) is born with Down's syndrome.
This does not entail a higher risk of early mortality unless associated with cardiac malformations. Other
associated conditions are malrotation (midgut volvulus is rare due to absent bowel distension and
peristalsis), biliary tract anomalies and Meckel's diverticulum. The diagnosis is suggested in utero by
the double-bubble image on ultrasound. Vomiting is the most frequent presenting symptom. UGIS is
diagnostic, showing a dilated stomach and first duodenal portion with scanty passage of contrast
material distally. Management varies accordingly to the type of stenosis: Ladd's bands are lysed. Pure
stenosis is opened longitudinally and closed transversely (Heineke-Mickulicz). Membranous stenosis is
resected. Successful endoscopic membranectomy of duodenal stenosis has been reported.
Duodeno-duodenostomy is the procedure of choice for annular pancreas. Diaphragms can rarely be
double. Anastomotic malfunction requiring prolonged intravenous nutrition and hospitalization has
prompted development of a diamond shape larger stoma. Tapering or plication of the dilated duodenum
is another effective method of improving disturbed transit. Other complications after surgery are
megaduodenum with blind loop syndrome, biliary reflux, cholestatic jaundice, delayed transit and bowel
obstruction. Early mortality is associated to prematurity and associated malformations. Long-term
follow-up is warranted to identify late problems.
 The diagnostic characteristics are: bilious vomiting, history of polyhydramnios in mother, KUB with classic "Double-bubble" appearance, a microcolon in barium enema study or malrotation.
 Treatment consist in: (1) duodeno-duodenostomy bypass for atresias, annular pancreas, and some stenosis. (2) duodenoplasty for webs, and stenosis, and (3) lysis of ladd's bands and Ladd's procedure for malrotation.  Associated anomalies are: Down's syndrome (20-30%), VACTERL syndrome, CNS anomalies and cardiac anomalies.

C. Malrotation and Volvulus

The rotation and normal fixation of the intestinal tract takes place within the first three months of fetal life. In the earliest stages when the intestinal tract is recognizable as a continuous tube, the stomach, small intestine, and colon constitute a single tube with its blood supply arising posteriorly. The midgut portion of this tube, from the second portion of the duodenum to the mid-transverse colon, lengthens and migrates out into an extension of the abdomen, which lies at the base of the umbilical cord. Here this loop of bowel undergoes a 270-degree counterclockwise twist at its neck. In the center of the twisted loop lie the blood vessels that will become the superior mesenteric artery and vein. After rotation, the small intestine quite rapidly withdraws into the abdominal cavity, with the duodenum and the proximal jejunum going first. During this process the duodenojejunal junction goes beneath and to the left of the base of the superior mesenteric vessels. This leaves the upper intestine, including the stomach and the duodenum, encircling the superior mesenteric vessels like a horseshoe with its opening on the left side of the embryo. The small intestine then follows into the abdomen, and withdrawal of the right half of the colon takes place so that it lies to the left. At the next step, the cecum and the right colon begin to travel across the top of the superior mesenteric vessels and then down to the right lower quadrant. The colon now lies draped across the top of the superior mesenteric vessels, again like a horseshoe, with its opening placed inferiorly. The duodenojejunal loop is said to attach to the posterior abdominal wall soon after its turn, whereas the mesenteric attachments of the entire colon and of the remaining small bowel gradually adhere after they arrive in their normal positions. In malrotation the right colon can create peritoneal attachments that include and obstruct the third portion of the duodenum (Ladd's bands).
 The diagnostic hallmarks are: bilious vomiting (the deadly vomit), abdominal distension and metabolic acidosis. A UGIS is more reliable than barium enema, most patients present in first month of life (neonatal), but may present at any time.
 The treatment is immediate operation; volvulus often means strangulation. Needs fluid and electrolyte replacement. Ladd's procedure consist of: reduce volvulus with a counterclockwise rotation, place small bowel in right abdomen, lysed ladd's bands, place large bowel in left abdomen, do an appendectomy. In cases of questionable non-viable bowel a second look procedure is required.

D. Intestinal Atresias

Meconium ileus is a neonatal intraluminal intestinal obstruction caused by inspissated meconium blocking the distal ileum. Occurs in 10-15% of all patients with cystic fibrosis, and 85-95% of patients with meconium ileus have cystic fibrosis. The meconium has a reduced water, abnormal high protein and mucoproteint content, the result of decreased pancreatic enzyme activity and prolonged small bowel intestinal transit time. Meconium Ileus is classified into two types: (1) Simple meconium ileus: The distal small bowel (10-30 cm of distal ileum) is relatively small, measuring less than 2 cm in diameter and contains concretions of gray, inspissated meconium with the consistency of thick glue or putty. It is often beaklike in appearance, conforming to the shape of the contained pellets. Proximally, the mid-ileum is large, measuring up to 7 cm in diameter. It is greatly distended by a mass of extremely thick, tenacious, dark green or tarry meconium. The unused small colon (microcolon) contains a small amount of inspissated mucus or grayish meconium. (2) Complicated meconium ileus: usually occurs during the prenatal period associated to volvulus, atresias, gangrene, perforation or peritonitis. A cystic mass or atresia of the bowel may occur. The degree of obstruction varies, may be cured in mild cases by rectal irrigations. Failure to pass meconium, abdominal distension and vomiting are seen in more severe cases. The diagnosis is suspected with findings of: multiple loops of dilated small bowel and coarse granular "soap-bubble" appearance on plain abdominal films. Some cases may show calcifications in the peritoneum (Meconium peritonitis). The Sweat Test is diagnostic of cystic fibrosis (value over 60 meq/L of sweat sodium or chloride are diagnostic). This test is not useful in infant during first weeks of life. Therapy is either: (1) Nonoperative- should be tried first. It consist of a careful gastrograffin enema after the baby is well-hydrated. Gastrograffin is a hyperosmolar aqueous solution of meglumine diatrizoate containing 0.1% polysorbate-80 (tween-80, a wetting agent) and 37% iodine. Its success is due to the high osmolarity (1700 mosm/liter) which draws fluid into the bowel and softens and loosens the meconium. (2) Surgical therapy that has included: ileostomy with irrigation, resection with anastomosis, and resection with ileostomy (Mikulicz, Bishop-Koop, and Santulli). Post-operative management includes: 10% acetylcysteine p.o., oral feedings (pregestimil), pancreatic enzyme replacement, and prophylactic pulmonary therapy. Long-term prognosis depends on the degree of severity and progression of cystic fibrosis pulmonary disease.

    Total colonic aganglionosis (TCA) is found in approx. 2 to 13% of patients with Hirschsprung's disease (2). There are three critical phases for patients with TCA (15).
 The first period comprises the time from birth until correct diagnosis. Patients with TCA present with a large variety of symptoms. Several authors have outlined the diagnostic problems in patients with TCA (2,4,18). Atypical symptoms may lead to excessively delayed diagnosis. Festen et al. report a delay in diagnosis up to 160 days after birth (4). Patients present with either ileus or symptoms as in typical Hirschsprung's disease but additionally with recurrent vomiting. In patients presenting with ileus, diagnosis may be delayed for several weeks because causative factors like volvulus or meconium ileus do not primarily warrant investigations for aganglionosis. Furthermore, TCA may be associated with other anomalies of the gastrointestinal tract. Only a few reports of TCA associated with small bowel atresia and volvulus can be found (3, 7). Lally et al. report anastomotic failure following repair of ileal atresia due to underlying extensive aganglionosis (11). In cases of midgut volvulus without malrotation, aganglionosis has to be ruled out. Stringer et al. recently published a series of seven full-term infants with meconium ileus due to extensive intestinal aganglionosis (18). Neonatal appendicitis, a very rare disease, may be the leading symptom of TCA. Therefore, rectal biopsies are mandatory in those cases. Ratta et al. state that lack of awareness of the condition may lead to delay in diagnosis and inappropriate treatment (15). Additional to the diagnostic problems due to atypical and heterogenic symptoms, histochemical examination of rectal biopsies may prove negative or equivocal because increased acetylcholinesterase activity may not be present in TCA (5,10,12). Furthermore, there is no typical radiographic pattern (13,17). Plain abdominal radiographs usually suggests low bowel obstruction whereas barium enema usually does not show pathognomonic features.
 If no mechanical obstruction is found at laparotomy in neonates presenting with ileus, it is suggested to resect the appendix to rule out TCA. If rectal mucosal biopsies are negative or equivocal, biopsies should be repeated or a formal sphincterectomy for thorough analysis is done.
 The second period lasts from the raising of stoma to its closure, including the definite surgical procedure. Failure to thrive and excessive fluid losses have been reported in patients with ileostomies (2). Post-ileostomy complications, however, have been eliminated after the importance of oral sodium supplementation to maintain the enteral co-transport system has been realized (16). In the series of Cass & Myers, ileostomy dysfunction was common with a 20% prolapse rate and 25% rate of persistent excessive losses (2). Interestingly, right transversostomies may show a good function even in cases of TCA. Therefore, frozen section biopsies are mandatory when raising a stoma.
 The definitive surgical procedure has been debated (2,5,8,9,15). Colonic patch graft procedures were the first proposals for surgical management of TCA (14). The rational behind were to use the distinctive resorptive function of part of the aganglionic colon (6). Use of the right colon has the theoretical advantage of improved water resorption. However the colon patch procedures have significant complications, e.g., enterocolitis, ulceration of the aganglionic pouch, perforations and extreme dilatation. Multiple modifications of the technique  have been reported but none were superior (1,8,9,18). Actually, a modified Duhamel's pull-through procedure seems favorable in the treatment of TCA (2,15).
 The third critical phase begins with closure of the stoma. Complications in this period are predominantly recurrent episodes of sub-ileus and diarrhea or nocturnal incontinence. The cause for sub-ileus is a raised tone in the residual sphincter. Repeated manual anal dilatations may be mandatory. The treatment of diarrhea may be managed by diets and/or Loperamide often in large doses. Side effects of large doses of Loperamide are mental irritability and dyskinesia.
 Significantly better survival of the patients with TCA nowadays is mainly attributed to more accurate diagnosis and improved management of infants with ileostomies.

References:
1. Boley SJ: A new approach to total aganglionosis of the colon. Surg Gynecol Obstet 159:481-484, 1984
2. Cass DT, Myers N: Total colonic aganglionosis: 30 years' experience. Pediatr Surg Int 2:68-75, 1987
3. Fekete CN, Ricour C, Martelli H: Total colonic aganglionosis (with or without ileal involvement): A review of 27 cases. J Pediatr Surg 21:251-254, 1986
4. Festen C: Total colonic aganglionosis: A diagnostic problem. Z Kinderchir 27:330-337, 1979
5. Festen C, Severijner R, v.d. Staak F: Total colonic aganglionosis: Treatment and follow-up. Z Kinderchir 44:153-155, 1989
6. Heath AL, Spitz L, Milla PJ: The absorptive function of colonic aganglionoic intestine: Are the Duhamel and Martin procedures rational? J Pediatr Surg 20:34-36, 1985
7. Ikeada K, Goto S: Total colonic aganglionosis with or without small bowel involvement: An analysis of 137 patients. J Pediatr Surg 21:319-322, 1986
8. Kimura K, Nishijima E, Muraji T: A new surgical approach to extensive aganglionosis. J Pediatr Surg 16:840-843, 1981
9. Kimura K, Nishijima E, Muraji T: Extensive aganglionosis: Further experience with the colonic patch graft procedure and long-term results. J Pediatr Surg 23:52-56, 1988
10. Kurer MH, Lawson JON, Pambakian H: Suction biopsy in Hirschsprung's disease. Arch Dis Child 61:83-84, 1986
11.Lally KP, Chwals WJ, Weitzman JJ: Hirschsprung's disease: A possible cause of anastomotic failure following repair of intestinal atresia. J Pediatr Surg 27:469-470, 1992
12. Lister J, Tam PKH: Hirschsprung's disease. In: Neonatal Surgery, Hrsg. Lister J, Irving IM, Burrterworth, London, p.523-546, 1990
13. Louw JH: Total colonic aganglionosis. Can J Surg 21:397-405, 1971
14.Martin L: Surgical management of Hirschsprung's disease involving the small intestine. Arch Surg 97:183-189, 1968
15.Ratta BS, Kiely EM, Spitz L: Improvements in the management of total colonic aganglionosis. Pediatr Surg Int 5:30-36, 1990
16. Sacher P, Hirsig J, Gresser J et al: The importance of oral sodium replacement in ileostomy patients. Progr Pediatr Surg 24:226-231, 1989
17. Swenson O, Sherman JO, Fisher JH: Diagnosis of congenital megacolon: an analysis of 501 patients. J Pediatr Surg 7:587-594, 1973
18. Stringer MD, Brereton RJ, Drake DP: Meconium ileus due to extensive intestinal  aganglionosis. J Pediatr Surg 29:501-503, 1994

* Author:
Peter Sacher, MD
Pediatric Surgical Department
University Children's Hospital
Zurich Switzerland

            Imperforate anus (IA) is a congenital anomaly in which the natural anal opening is absent. Diagnosis of IA is usually made shortly after birth on routine physical examination. The incidence of IA is approximately 1 in 4000-5000 live births and it is more common in males. Its etiology is unknown and it runs equally through all racial, cultural and socio-economic groups. There is preliminary evidence (> 5 case reports) of the existence of autosomal inheritance (both dominant and recessive) in patients with anorectal malformations.
            IA is classified as either "high" or "low" depending on the termination of the distal rectum. When the rectum ends above the levator muscles the malformations are classified as high, and when the rectum ends below the levator muscles the malformations are classified as low. High lesions are more frequent in males, low ones in females. Determination of the level of the lesion (by abdominal x-ray or perineal ultrasound) is critical for appropriate management. Children who have IA may also have other congenital anomalies. The acronym VACTERL describes the associated problems that infants with IA may have: Vertebral defects, Anal atresia, Cardiac anomalies, Tracheoesophageal fistula, Esophageal atresia, Renal anomalies, and Limb anomalies.
            Repair of low IA is relatively simple and is usually treated with perineal anoplasty; however, repair of high IA is more complex. Patients are initially given a temporary colostomy and time is given to allow the child to grow. A pull-through operation is completed at a later date. Independent of the level of the lesion, the goal of the surgery is the creation of adequate nerve and muscle structures around the rectum and anus to provide the child with the capacity for bowel control.
            MALES: most important decision in the initial management of Imperforate Anus (IA) male patient during the neonatal period is whether the baby needs a colostomy and/or another kind of urinary  diversion procedure to prevent sepsis or metabolic derangements. Male patients will benefit from perineal inspection to check for the presence of a fistula (wait 16-24 hours of life before deciding). During this time start antibiotherapy, decompress the GI tract, do a urinalysis to check for meconium cells, and an ultrasound of abdomen to identify urological associated anomalies.  Perineal signs in low malformations that will NOT need a colostomy are: meconium in perineum, bucket-handle defect, anal membrane and anal stenosis. These infants can be managed with a perineal anoplasty during the neonatal period with an excellent prognosis. Meconium in urine shows the pt has a fistula between the rectum and the urinary tract. Flat "bottom" or perineum (lack of intergluteal fold), and absence of anal dimple indicates poor muscles and a rather high malformation needing a colostomy. Patients with no clinical signs at 24 hours of birth will need a invertogram or cross-table lateral film in prone position to decide rectal pouch position. Bowel > 1 cm from skin level will need a colostomy, and bowel < 1 cm from skin can be approach perineally. Those cases with high defect are initially managed with a totally diverting colostomy. Diverting the fecal stream reduces the chances of genito-urinary tract contamination and future damage.
            FEMALES: most frequent defect in females patient with imperforate anus (IA) is vestibular fistula, followed by vaginal fistulas. In more than 90% of females cases perineal inspection will confirm the diagnosis.  These infants require a colostomy before final corrective surgery. The colostomy can be done electively before discharge from the nursery while the GI tract is decompressed by dilatation of the fistulous tract. A single orifice is diagnostic of a persistent cloacal defect usually accompany with a small-looking genitalia. Cloacas are associated to distended vaginas (hydrocolpos) and urologic malformations. This makes a sonogram of abdomen very important in the initial management of these babies for screening of obstructive uropathy (hydronephrosis and hydroureter). Hydrocolpos can cause compressive obstruction of the bladder trigone and interfere with ureteral drainage. Failure to gain weight and frequents episodes of urinary tract infections shows a poorly drained urologic system. A colostomy in cloacas is indicated.  10% of babies will not pass meconium and will develop progressive abdominal distension. Radiological evaluation will be of help along with a diverting colostomy in this cases. Perineal fistulas can be managed with cutback without colostomy during the neonatal period.
            The most important prognostic characteristic is the severity of the IA. Patients with low IA have a good probability of having normal stool patterns. Patients with high IA report more problems such as fecal incontinence and constipation. For patients who cannot maintain normal bowel function, the use of a special diet, underpants liners, enemas and drugs have ameliorated their lives. Long-term follow up (with both qualitative and quantitative quality of life considerations) of these patients is very important. In addition, the use of anal endosonography and/or manometry can be used as objective measurements of anorectal pressure and sphincter function.

References
1- Chen CJ: The treatment of imperforate anus: experience with 108 patients. J Pediatr Surg 34(11):1728-32, 1999.
2- Landau D, Mordechai J, Karplus M, Carmi R: Inheritance of familial congenital isolated anorectal malformations: case reports and review. Am J Med Genetics 71:280-282, 1997.
3- Rintala RJ, Lindahl HG, Rasanen M: Do children with repaired low anorectal malformations have normal bowel function? J Pediatr Surg 32(6):823-826, 1997.
4- Peña A: Anorectal malformations. Semin Pediatr Surg 4(1):35-47, 1995
5- Peña A: Management of anorectal malformations during the newborn period. World J Surg 17(3):385-92, 1993
6- Peña A: Posterior sagittal approach for the correction of anorectal malformations. Adv Surg 19:69-100, 1986
7- Peña A: Surgical treatment of high imperforate anus. World J Surg 9(2):236-43, 1985
8- deVries PA, Peña A: Posterior sagittal anorectoplasty. J Pediatr Surg 17(5):638-43, 1982

H. Duplications

Duplications of the gastrointestinal tract are considered uncommon congenital anomalies usually diagnosed or unexpectedly encountered intraoperatively during the first two years of life. The duplicated bowel can occur anywhere in the GI tract, is attached to the mesenteric border of the native bowel, shares a common wall and blood supply, coated with smooth muscle, and the epithelial lining is GI mucosa. May contain ectopic gastric or pancreatic tissue. Most are saccular, other tubular. Theories on their origin (split notochord syndrome, twining, faulty solid-stage recanalization) do not explain all cases of duplicated bowel. Three-fourth are found in the abdomen (most commonly the ileum and jejunum), 20% in the thorax, the rest thoraco-abdominal or cervical. Symptoms vary according to the size and location of the duplication. Clinical manifestations can range from intestinal obstruction, abdominal pain, GI bleeding, ulceration, or mediastinal compression. Ultrasound confirms the cystic nature of the lesion (muscular rim sign) and CT the relationship to surrounding structures. Management consist of surgical excision avoiding massive loss of normal bowel and removing all bowel suspect of harboring ectopic gastric mucosa.

     Although intussusception can occur at any age, the greatest incidence occurs in infants between 4-10 months of age. Over half of the cases are in the first year of life. Frequently occurs after a recent upper respiratory infection, by Adenovirus type 3 that causes a reactive lymphoid hyperplasia that act as lead point (of Peyer's patch).
     A definite lead point is identified in about 5% of patients. These include: Meckel's diverticulum, polyps, Henoch's Schonlein purpura, hematoma, lymphoma, foreign bodies, and duplications. Most children have no lead point and it is felt that enlarged mesenteric nodes or swollen Peyer's patches may be the cause. The baby has intermittent periods of severe discomfort with screaming, stiffening and drawing up of the legs, followed by periods of rest. Vomiting may occur and bloody, mucoid (currant jelly) stool may be passed. The baby may become dehydrated and appear acutely ill. Frequently, lethargy may be an early sign. The diagnosis is made by barium enema, and hydrostatic reduction of the intussusception with barium is successful in approximately 50% of cases. To be successful, the barium must reflux into the terminal ileum. The surgeon should be notified before an attempt at barium reduction, and should be present at the time of study. Recently the use of gas enema reduction has been successful in patients with: (1) symptoms less than 12 hours, (2) no rectal bleeding, (3) absence of small bowel obstruction, and (4) normally hydrated. Ultrasonography can be used as a rapid sensitive screening procedure in the initial diagnosis of intussusception. Previous adverse clinical features that precluded barium reduction can be replaced during gas reduction. Predictors of failure of reduction are: (1) ileocolic intussusception, (2) long duration of symptoms, (3) rectal bleeding, and (4) failed reduction at another institution. Air reduction (pneumocolon) is a very effective alternative method since it brings less radiation (shorter flouroscopy time), less costs and less morbidity in cases of perforations.
     Failure of hydrostatic reduction requires urgent operation through a right lower quadrant horizontal incision. The intussusception is reduced by pushing on the distal bowel like a tube of toothpaste rather than pulling the proximal bowel. Most cases are ileo-colic intussusception, and a few are jejuno-jejunal or ileo-ileal intussusception.
    The traditional method of diagnosing and managing ileo-colic intussusception is barium enema contrast reduction. In China where this is the most common surgical emergency in childhood, pneumatic reduction has been used for more than 25 years. A recent tendency toward this approach is seen in recent years in Occident. This consist of rectal insufflation of oxygen at a flow rate of 2 L/min, controlling pressure by adjusting the height of the mercury column, and using maximal pressures of 80 mm Hg. Small bowel aeration is a sign of complete reduction. Series are successful in 70-90% of cases. Gas enema reduction is very successful in patients with: (1) symptoms less than 12 hours, (2) no rectal
bleeding, (3) absence of small bowel obstruction, and (4) normally hydrated. Ultrasonography can be
used as a rapid sensitive screening procedure in the initial diagnosis of intussusception. Previous
adverse clinical features that precluded barium reduction can be replaced during gas reduction.
Predictors of failure of reduction are: (1) ileocolic intussusception, (2) long duration of symptoms, (3)
rectal bleeding, and (4) failed reduction at another institution. Air reduction (pneumocolon) is a very
effective alternative method since it brings less radiation (shorter flouroscopy time), less costs and less
morbidity in cases of perforations.
 
 

K.Chronic Intestinal Pseudo-Obstruction

Chronic Intestinal Pseudo-Obstruction is a rare disorder of intestinal motility in infants and children characterized by recurrent attacks of abdominal pain, distension, vomiting, constipation and weight loss in the absence of obvious mechanical lesions. The disease can be familial or sporadic. Suggested etiology is degeneration of enteric nervous or smooth muscle cells. The diagnosis is based on history, physical exam, radiographies and motility studies. X-Ray hallmarks are: absent strictures, absent, decreased or disorganized intestinal motility, and dilated small/large bowel loops. Associated conditions identified in 10-30% of patients are bladder dysfunction (megacystis) and neurological problems. Histologic pattern portrayed: myenteric plexus hyperplasia, glial cell hyperplasia, and small ganglion cells (hypoganglionosis). Management is primary supportive: intestinal decompression (NG), long-term TPN and antibiotic prophylaxis. Motility agents are unsuccessful. Venting gastrostomy with home parenteral nutrition has shortened the high hospitalization rate associated to this disease process. A similar condition can be seen in early fed prematures due to immaturity of intestinal motility.

L.Bezoars

Bezoars are rare foreign body concretions formed in the stomach and small bowel composed mainly of hair (tricho), vegetable matter (phyto) or milk curds (lacto). Most cases are females children, 6-10 years old, with bizarre appetite (trichophagia) and emotional disturbances. Originally the mass forms in the stomach and can move to the small bowel by fragmentation, extension or total translocation. Diagnosis can be confirmed by UGIS, CT-Scan or endoscopy. The child can develop an asymptomatic palpable abdominal mass, pain, obstruction or perforation. Other children will reduce intake and develop weight loss. Predisposing conditions to bezoar formations are: gastric dymotility and decreased acidity. Management can consist of mechanical or pulsating jet of water fragmentation via the endoscope, operative extraction, shock-wave lithotripsy (ESWL) with subsequent evacuation, or dissolution by oral ingestion of proteolytic enzymes (papain, acetylcysteine, cellulase). With ESWL the shock wave pressure needed is less than half used for urolithiasis cases.

    Intestinal Neuronal Dysplasia (IND) is a colonic motility disorder first described in 1971 by Meier-Ruge associated to characteristic histochemical changes of the bowel wall (hyperplasia of submucous & myenteric plexus with giant ganglia formation,  isolated ganglion cells in lamina propia and muscularis mucosa, elevation of acetylcholinesterase in parasympathetic fiber of lamina propia and circular muscle, and myenteric plexus sympathetic hypoplastic innervation), also known as hyperganglionosis associated to elevated acetylcholinesterase parasympathetic staining. The condition can occur in an isolated form (either localized to colon or disseminated throughout the bowel), or associated to other diseases such as Hirschsprung's (HD), neurofibromatosis, MEN type IIB, and anorectal malformations. It is estimated that 20-75% of HD cases have IND changes proximal to the aganglionic segment. Clinically two different types of isolated IND have been described: Type A shows symptoms of abdominal distension, enterocolitis, bloody stools, intestinal spasticity in imaging studies (Ba Enema) since birth, is less common and associated with hypoplasia of sympathetic nerves. Type B is more frequent, symptoms are indistinguishable from that of HD, with chronic constipation, megacolon, and repeated episodes of bowel obstruction. Management depends on clinical situation; conservative for minor symptoms until neuronal maturation occurs around the 4th year of life, colostomy and resectional therapy for life threatening situations.
 

A. Diaphragmatic Hernias

A.1 Congenital Diaphragmatic Hernia (Bochdalek)

The most common congenital diaphragmatic hernia (CDH) is that which occurs through the postero-lateral defect of Bochdalek. It is caused by failure of the pleuroperitoneal membrane to develop adequately and close before the intestines returning to the abdomen at the tenth week of gestation. The intestines then enter the pleural cavity and cause poor lung development leading to pulmonary hypoplasia (a reduced number of alveoli per area of lung tissue). This defect is postero-lateral in the diaphragm and may vary in size. Stomach, liver or spleen may be partly in chest as well. Frequency is 1:2000 live births and the natural history in prenatally diagnosed CDH is that 60% will die. The clinical presentation is that the newborn becomes rapidly cyanotic, acidotic, and has poor ventilation. Major findings relate to the degree of pulmonary maldevelopment. Chest films will show intestines in the chest. Left sided hernias are more common than right (90% on left). Placement of a radiopaque nasogastric tube may show the tube coiled in the lower left chest. Higher risk factors are: early appearance of symptoms in life, prematurity and associated anomalies. Treatment consist of rapid intubation and ventilation with use of muscle relaxants, placement of a nasogastric tube to prevent gaseous distension of the intestines and preoperative stabilization of arterial blood gases and acid-base status. Surgery can be undertaken when one of the following objectives are met: (1) blood gases normalize with no significant changes between preductal and postductal samples, (2) echocardiogram demonstrate reduce pulmonary pressure and pulmonary peripheral resistance.
 Operative management consist of abdominal approach, closure of hernia by primary repair or use of mesh, and correction of malrotation. Postoperative management is very difficult. Due to hypoplastic lungs, there is frequently pulmonary hypertension leading to right-to-left shunting and progressive hypoxemia, hypercarbia, and acidosis that worsens the pulmonary hypertension. The use of chest tubes may cause overstretching of the already hypoplastic alveoli causing: increase pulmonary hypertension, reduce functional residual capacity and reduce lung compliance. Postoperatively, the infant should be kept paralyzed and ventilated and only very slowly weaned from the ventilator. The severity of pulmonary hypoplasia, both ipsilaterally and contralaterally, is the main determinant of outcome. ECMO (extracorporeal membrane oxygenator) has come to reduce somewhat the mortality of this condition.
 The mortality of CDH is directly related to the degree of lung hypoplasia associated. Death is caused by persistent pulmonary hypertension and right ventricular failure. Prospective studies of prenatally diagnosed fetus prior to 25 wk. gestation has shown that 60% will die despite optimal postnatal care. This unsolved problem has prompted investigators to develop new treatment options such as preoperative stabilization, jet-frequency ventilation, and ECMO. Another area of development is intrauterine fetal surgical repair. To achieve success fetal surgery should:  (1) pose no risk to the mother (innocent bystander) or her future reproductive capacity; (2) tocolytic therapy in the post-op weeks should proved effective to avoid prenatal stillbirths; and  (3) the procedure should be superior to conventional therapy. Intrauterine repair has meet with limited success due to herniation of the fetal liver into the chest through the defect. Disturbance of the umbilical circulation during or after liver reduction causes fetal death. Positive-pressure ventilation after birth reduces the liver before the baby comes for surgical repair. Dr. Harrison (USFC Fetal Treatment Center) has devised separate fetal thoraco-abdominal incisions to deal with this problem ("two-step dance"), reducing or amputating the left lateral segment of the liver. Another less invasive approach is enlarging the hypoplastic lungs by reducing the normal egress of fetal lung fluid with controlled tracheal obstruction called PLUGS (Plug Lung Until it Grows).
 Delayed presentation beyond the neonatal period is rare, estimated to occur in 4-6% of cases. Infants and children will present with either respiratory or gastrointestinal symptoms such as: chronic respiratory tract infection, vomiting, intermittent intestinal obstruction, and feeding difficulty. Occasionally the child is asymptomatic. The small size of the defect protected by either the spleen or the liver and the presence of a hernial sac may  delay the intestinal herniation into the chest. A rise intrabdominal pressure by coughing or vomiting transmitted to any defect of the diaphragm makes visceral herniation more likely. Diagnosis is confirmed by chest or gastrointestinal contrast imaging. Management consists of immediate surgery after preop stabilization. Most defects can be closed primarily through an abdominal approach. Chest-tube placement in the non-hypoplastic lung is of help. Surgical results are generally excellent. A few deaths have resulted from cardiovascular and respiratory compromise due to visceral herniation causing mediastinal and pulmonary compression.

A.2 Morgagni Hernias

First described in 1769, Morgagni Hernias (MH) are rare congenital diaphragmatic defects close to the
anterior midline between the costal and sternal origin of the diaphragm. They occur retrosternally in the
midline or more commonly on either side (parasternally) of the junction of the embryologic septum
transversum and thoracic wall (see the figure) representing less than 2% of all diaphragmatic defects.
Almost always asymptomatic, typically present in older children or adults with minimal gastrointestinal
symptoms or as incidental finding during routine chest radiography (mass or air-fluid levels). Infants
may develop respiratory symptoms (tachypnea, dyspnea and cyanosis) with distress. Cardiac
tamponade due to protrusion into the pericardial cavity has been reported. The MH defect contains a
sac with liver, small/ large bowel as content. Associated conditions are: heart defects, trisomy 21,
omphalocele, and Cantrells' pentalogy. US and CT-Scan can demonstrate the defect. Management is
operative. Trans-abdominal subcostal approach is preferred with reduction of the defect and suturing of
the diaphragm to undersurface of sternum and posterior rectus sheath. Large defects with phrenic
nerve displacement may need a thoracic approach. Results after surgery rely on associated conditions.

A.3 Esophageal Hernias

Two types of esophageal hernia recognized are the hiatal and paraesophageal hernia. Diagnosis is
made radiologically always and in a number of patients endoscopically. The hiatal hernia (HH) refers to
herniation of the stomach to the chest through the esophageal hiatus. The lower esophageal sphincter
also moves. It can consist of a small transitory epiphrenic loculation (minor) up to an upside-down
intrathoracic stomach (major). HH generally develops due to a congenital, traumatic or iatrogenic factor.
Most disappear by the age of two years, but all forms of HH can lead to peptic esophagitis from
Gastroesophageal reflux. Repair of HH is determined by the pathology of its associated reflux (causing
failure to thrive, esophagitis, stricture, respiratory symptoms) or the presence of the stomach in the
thoracic cavity. In the paraesophageal hernia (PH) variety the stomach migrates to the chest and the
lower esophageal sphincter stays in its normal anatomic position. PH is a frequent problem after
antireflux operations in patients without posterior crural repair. Small PH can be observed. With an
increase in size or appearance of symptoms (reflux, gastric obstruction, bleeding, infarction or
perforation) the PH should be repaired. The incidence of PH has increased with the advent of the
laparoscopic fundoplication.

PROCESUS VAGINALIS REMNANTS

B.1 Inguinal Hernias

 A hernia is defined as a protrusion of a portion of an organ or tissue through an abnormal opening. For groin (inguinal or femoral) hernias, this protrusion is into a hernial sac. Whether or not the mere presence of a hernial sac (or processus vaginalis) constitutes a hernia is debated. Inguinal hernias in children are almost exclusively indirect type. Those rare instances of direct inguinal hernia are caused by previous surgery and floor disruption. An indirect inguinal hernia protrudes through the internal inguinal ring, within the cremaster fascia, extending down the spermatic cord for varying distances. The direct hernia protrudes through the posterior wall of the inguinal canal, i.e., medial to deep inferior epigastric vessels, destroying or stretching the transversalis fascia. The embryology of indirect inguinal hernia is as follows: the duct descending to the testicle is a small offshoot of the great peritoneal sac in the lower abdomen. During the third month of gestation, the processus vaginalis extends down toward the scrotum and follows the chorda gubernaculum that extends from the testicle or the retroperitoneum to the scrotum. During the seventh month, the testicle descend into the scrotum, where the processus vaginalis forms a covering for the testicle and the serous sac in which it resides. At about the time of birth, the portion of the processus vaginalis between the testicle and the abdominal cavity
obliterates, leaving a peritoneal cavity separate from the tunica vaginalis that surrounds the testicle.
 Approximately 1-3% of children have a hernia. For infants born prematurely, the incidence varies from 3-5%. The typical patient with an inguinal hernia has an intermittent lump or bulge in the groin, scrotum, or labia noted at times of increased intra-abdominal pressure. A communicating hydrocele is always associated with a hernia. This hydrocele fluctuates in size and is usually larger in ambulatory patients at the end of the day. If a loop of bowel becomes entrapped (incarcerated) in a hernia, the patient develops pain followed by signs of intestinal obstruction. If not reduced, compromised blood supply (strangulation) leads to perforation and peritonitis. Most incarcerated hernias in children can be reduced.
 The incidence of inguinal hernia (IH) in premature babies (9-11%) is higher than full-term (3-5%), with a dramatic risk of incarceration (30%). Associated to these episodes of incarceration are chances of: gonadal infarction (the undescended testes complicated by a hernia are more vulnerable to vascular compromise and atrophy), bowel obstruction and strangulation. Symptomatic hernia can complicate the clinical course of babies at NICU ill with hyaline membrane, sepsis, NEC and other conditions needing ventilatory support. Repair should be undertaken before hospital discharge to avoid complications. Prematures have: poorly developed respiratory control center, collapsible rib cage, deficient fatigue-resistant muscular fibers in the diaphragm that predispose then to potential life-threatening post-op respiratory complications such as: need of assisted ventilation (most common), apnea and bradycardia, emesis, cyanosis and re-intubation (due to laryngospasm). Independent risk factors associated to this complications are (1) history of RDS/bronchopulmonary dysplasia, (2) history of patent ductus arteriosus, (3) low absolute weight (< 1.5 Kg), and (4) anemia (Hgb < 10 gm- is associated to a higher incidence of post-op apnea). Postconceptual age (sum of intra- and extrauterine life) has been cited as the factor having greatest impact on post-op complications. These observation makes imperative that preemies (with post conceptual age of less than 45 weeks) be carefully monitored in-hospital for at least 24 hours after surgical repair of their hernias. Outpatient repair is safer for those prematures above the 60 wk. of postconceptual age. The very low birth weight infant with symptomatic hernia can benefit from epidural anesthesia.
 At times, the indirect inguinal hernia will extend into the scrotum and can be reduced by external, gentle pressure. Occasionally, the hernia will present as a bulge in the soft tissue overlying the internal ring. It is sometimes difficult to demonstrate and the physician must rely on the patient's history of an intermittent bulge in the groin seen with crying, coughing or straining.
 Elective herniorrhaphy at a near convenient time is treatment of choice. Since risk of incarceration is high in children, repair should be undertaken shortly after diagnosis. Simple high ligation of the sac is all that is required. Pediatric patients are allowed to return to full activity immediately after hernia repair. Patients presenting with incarceration should have an attempt at reduction (possible in greater than 98% with experience), and then admission for repair during that hospitalization. Bilateral exploration is done routinely by most experienced pediatric surgeons. Recently the use of groin laparoscopy through the hernial sac permits visualization of the contralateral side.
 Approximately 1% of females with inguinal hernias will have the testicular feminization syndrome. Testicular feminization syndrome (TFS) is a genetic form of male pseudohermaphroditism (patient who is genetically 46 XY but has deficient masculinization of external genitalia) caused by complete or partial resistance of end organs to the peripheral effects of androgens. This androgenic insensitivity is caused by a mutation of the gene for androgenic receptor inherited as an X-linked recessive trait. In the complete form the external genitalia appear to be female with a rudimentary vagina, absent uterus and ovaries. The infant may present with inguinal hernias that at surgery may  contain testes. Axillary/pubic hair is sparse and primary amenorrhea is present. The incomplete form may represent undervirilized infertile men. Evaluation should include: karyotype, hormonal assays, pelvic ultrasound, urethrovaginogram, gonadal biopsy and labial skin bx for androgen receptor assay. This patients will never menstruate or bear children. Malignant degeneration (germ cell tumors) of the gonads is increased (22-33%). Early gonadectomy is advised to: decrease the possible development of malignancy, avoid the latter psychological trauma to the older child, and eliminate risk of losing the pt during follow-up. Vaginal reconstruction is planned when the patient wishes to be sexually active. These children develop into very normal appearing females that are sterile since no female organs are present.

B.2 Hydroceles

A hydrocele is a collection of fluid in the space surrounding the testicle between the layers of the tunica vaginalis. Hydroceles can be scrotal, of the cord, abdominal, or a combination of the above. A hydrocele of the cord is the fluid-filled remnant of the processus vaginalis separated from the tunica vaginalis. A communicating hydrocele is one that communicates with the peritoneal cavity by way of a narrow opening into a hernial sac. Hydroceles are common in infants. Some are associated with an inguinal hernia. They are often bilateral, and like hernias, are more common on the right than the left. Most hydroceles will resolved spontaneously by 1-2 years of age. After this time, elective repair can be performed at any time. Operation is done through the groin and search made for an associated hernia. Aspiration of a hydrocele should never be attempted. As a therapeutic measure it is ineffective, and as a diagnostic tool it is a catastrophe if a loop of bowel is entrapped. A possible exception to this is the postoperative recurrent hydrocele.

C. Undescended Testis

    The undescended testis is a term we use to describe all instances in which the testis cannot be manually manipulated into the scrotum. The testes form from the medial portion of the urogenital ridge extending from the diaphragm into the pelvis. In arrested descent, they may be found from the kidneys to the internal inguinal ring. Rapid descent through the internal inguinal ring commences at approximately week 28, the left testis preceding the right. Adequate amounts of male hormones are necessary for descent. The highest levels of male hormones in the maternal circulation have been demonstrated at week 28. Thus, it appears that failure of descent may be related to inadequate male hormone levels or to failure of the end-organ to respond.  The undescended testes may be found from the hilum of the kidney to the external inguinal ring. A patent processus vaginalis or true hernial sac will be present 90% of the time.
    The undescended testis found in 0.28% of males can be palpable (80%; most at inguinal canal), or
non-palpable (20%). Testes that can be manually brought to the scrotum are retractile and need no
further treatment. Parents should know the objectives, indications and limitations of an orchiopexy: that
the testis could not exist (testicular vanishing syndrome), even after descend can atrophy, that it cannot
be fixed and removal is a therapeutic possibility. To improve spermatogenesis (producing an adequate
number of spermatozoids) surgery should be done before the age of two. Electron microscopy has
confirmed an arrest in spermatogenesis (reduced number of spermatogonias and tubular diameter) in
undescended testis after the first two years of life. Other reasons to pex are: a higher incidence of
malignancy, trauma and torsion, and future cosmetic and psychological problems in the child. The
management is surgical; hormonal (Human Chorionic Gonadotropin) treatment has brought conflicting
results except bilateral cases. Surgery is limited by the length of the testicular artery. Palpable testes
have a better prognosis than non-palpable. Laparoscopy can be of help in non-palpable testis avoiding
exploration of the absent testis.

D. Umbilical Hernias
by: Adrian M. Viens, MS
University of Toronto

An umbilical hernia is a small defect in the abdominal fascial wall in which fluid or abdominal contents protrude through the umbilical ring. The presence of a bulge within the umbilicus is readily palpable and becomes more apparent when the infant cries or during defecation. The actual size of the umbilical hernia is measured by physical examination of the defect in the rectus abdominis muscle, and not by the size of the umbilical bulge. The size of the fascial defect can vary from the width of a fingertip to several centimetres.Embryologically, the cause of an umbilical hernia is related to the incomplete contraction of the umbilical ring. The herniation of the umbilicus is a result of the growing alimentary tract that is unable to fit within the abdominal cavity. Umbilical hernias are more prevalent in females than in males and are more often seen in patients with African heritage. The increased frequency of umbilical hernias has also been attributed to premature babies, twins and infants with long umbilical cords. There is also a frequent association with disorders of mucopolysaccharide metabolism, especially Hurler's Syndrome (gargoylism).Most umbilical hernias are asymptomatic; the decision to repair the umbilical hernia in the first years of life is largely cosmetic and is often performed because of parental request, not because of pain or dysfunction. In the past, some parents use to tape a coin over the umbilical bulge, however, manual compression does not have an effect on the fascial defect.Treatment of umbilical hernia is observation. Most umbilical hernias spontaneously close by age two, with 90% closed by age three and 95% closed by age five. However, surgical repair is recommended if the hernia has not closed by the age of five.If a large defects (> 2cm) remains after the age of 2, spontaneously repair in unlikely and may be closed surgically. The incidence of incarceration (trapped intestinal loop) is rare, even in larger defects. Females should especially have their umbilical hernia corrected before pregnancy because of the associated increased intra-abdominal pressure that could lead to complications. The procedure is simple and incidence of complication such as infection is extremely rare. The repair is usually done as outpatient surgery under general anesthetic.

References:
1-Skandalakis JE, Gray SW (eds): Embryology for surgeons: the embryological basis for treatment of congenital anomalies - 2nd edition. Williams & Wilkins, Baltimore, pp. 563-67, 1994
2- Skinner MA, Grosfeld JL: Inguinal and umbilical hernia repair in infants and children. Surg Clinics of North Am 73(3): 439-49, 1993
3- Raffensperger JG (ed): Swenson's Pediatric Surgery - 5th edition. Appleton & Lange, Norwalk, Connecticut, pp.195, 1990
4- Moore KL: The developing human - 4th edition. Philadelphia, WB Saunders, pp. 231-34, 279-81, 1988
5-Woods GE: Some observations on umbilical hernias in infants. Arch Dis Child 28:450-62, 1953
6- Evans AG: The comparative incidence of umbilical hernias in colored and white infants. J Natl Med Assoc 33:158-60, 1944

E. Omphalocele

The three most common abdominal wall defect in newborns are umbilical hernia, gastroschisis and
omphalocele. Omphalocele is a milder form of primary abdominoschisis since during the embryonic
folding process the outgrowth at the umbilical ring is insufficient (shortage in apoptotic cell death).
Bowel and/or viscera remains in the umbilical cord causing a large abdominal wall defect. Defect may
have liver, spleen, stomach, and bowel in the sac while the abdominal cavity remains underdeveloped in
size. The sac is composed of chorium, Wharton's jelly and peritoneum. The defect is centrally localized
and measures 4-10 cm in diameter. A small defect of less than 2 cm with bowel inside is referred as a
hernia of the umbilical cord. There is a high incidence (30-60%)of associated anomalies in patients with
omphalocele. Epigastric localized omphalocele are associated with sternal and intracardiac defects (i.e.,
Pentalogy of Cantrell), and hypogastric omphalocele have a high association with genito-urinary
defects (i.e., Cloacal Exstrophy). All have malrotation. Cardiac, neurogenic, genitourinary, skeletal and
chromosomal changes and syndromes are the cornerstones of mortality. Antenatal diagnosis may
affect management by  stimulating search for associated anomalies and changing the site, mode or
timing of delivery. Cesarean section is warranted in large omphaloceles to avoid liver damage and
dystocia. After initial stabilization management requires consideration of the size of defect, prematurity
and associated anomalies. Primary closure with correction of the malrotation should be attempted
whenever possible. If this is not possible, then a plastic mesh/silastic chimney is fashioned around the
defect to cover the intestinal contents and the contents slowly reduced over 5-14 days. Antibiotics and
nutritional support are mandatory. Manage control centers around sepsis, respiratory status, liver and
bowel dysfunction from increased intraabdominal pressure.

F. Gastroschisis

Gastroschisis is  a congenital evisceration of part of the abdominal content through an anterior
abdominal wall defect found to the right of the umbilicus. The protruding gut is foreshortened, matted,
thickened and covered with a peel. In a few babies (4 to 23%) an intestinal atresia (IA) further
complicates the pathology. IA complicating gastroschisis may be single or multiple and may involve the
small  or large bowel. The IA might be the result of pressure on the bowel from the edge of the defect
(pinching effect) or an intrauterine vascular accident. Rarely, the orifice may be extremely narrow
leading to gangrene or complete midgut atresia. In either case the morbidity and mortality of the child is
duplicated with the presence of an IA. Management remains controversial. Alternatives depend on the
type of closure of the abdominal defect and the severity of the affected bowel. With primary fascial
closure and good-looking bowel primary anastomosis is justified. Placement of a silo calls for delayed
resection performing a second look operation at a  later stage to save intestinal length. Angry looking
dilated bowel prompts for proximal diversion, but the higher the enterostomy the greater the problems
of fluid losses, electrolyte imbalances, skin excoriation, sepsis and malnutrition. Closure of the def