1. What are branchial cleft anomalies?

Show answer
Cysts, sinuses, and fistulas that result from incomplete obliteration of the first, second, or third branchial clefts, and are present in early fetal development.

2. Which anomaly is the most common?

Show answer
Second branchial cleft anomalies are by far the most common, presenting near the mid- to upper border of the sternocleidomastoid (SCM) muscle. First branchial remnants are less common and third clefts are quite rare. (See Table 88-1.)
Table 88-1. BRANCHIAL CLEFT ANOMALIES

3. How do patients with branchial cleft anomalies present?

Show answer
Those with complete fistulas or sinuses present with intermittent drainage of a mucoid fluid on the neck. Patients with cysts usually present later with a mass (sterile or infected). Complete surgical excision is the treatment of choice.

4. What are the major operative hazards of branchial cleft remnant excision?

Show answer
The second branchial cleft tracts through the bifurcation of the carotid artery. The facial nerve is in close proximity to the first branchial cleft fistula. The superior laryngeal nerve and the recurrent laryngeal nerve are both at risk in dissection of a third branchial cleft.

5. What is a thyroglossal duct cyst?

Show answer
A thyroglossal duct cyst is the most common congenital cyst found in the neck. It is caused by failure of normal obliteration of the migration tract of the thyroid gland. Embryologically, the thyroid descends from the base of the tongue (foramen caecum) to its normal location in the low anterior neck.

6. How do patients with thyroglossal duct cysts present?

Show answer
They present with a paramidline mass in the upper neck; if infected, they may present with fever, tenderness, and erythema.

KEY POINTS: CONGENITAL CYSTS AND SINUSES OF THE NECK

1. The most common brachial cleft anomaly is the second brachial cleft anomaly presenting near the mid- to upper border or the sternocleidomastoid muscle.
2. A thyroglossal duct cyst is the most common congenital cyst found in the neck.
3. A cystic hygroma is a congenital lymphatic malformation that is benign an usually presents as a soft mass in the lateral neck.

7. How are thyroglossal duct cysts treated?

Show answer
The best treatment is complete excision of the cyst, along with the tract. Because embryologically the thyroid descends before formation of the hyoid cartilage, the tract may pass right through the hyoid. Therefore, complete tract removal requires excision of the central portion of the hyoid and dissection up to the base of the tongue (i.e., the Sistrunk procedure).

8. What is a cystic hygroma?

Show answer
A cystic hygroma is a congenital lymphatic malformation with a predilection for the neck. It is a benign lesion that usually presents as a soft mass in the lateral neck. Excision is often challenging because the lymph cysts do not respect the fascial planes and often intertwine with the neurovascular structures in the neck. Near-total excision is the treatment of choice.

References
BIBLIOGRAPHY
1. Alqahtani A, Nguyen LT, Flageole H, et al: 25 years experience with lymphangioma in children. J Pediatr Surg 34:1164-1168, 1999. Medline Similar articles Full article
2. Brown RL, Azizkhan RG: Pediatric head and neck lesions. Pediatr Clin North Am 45:889-905, 1998. Medline Similar articles
3. Kang L, Chang CH, Yu CH, et al: Prenatal detection of cystic hygroma using three-dimensional ultrasound. Ultrasound Med Biol 28:719, 2002. Medline Similar articles
4. Organ GM, Organ CH Jr: Thyroid gland and surgery of the thyroglossal duct: Exercise in applied embryology. World J Surg 24:886-890, 2000.
5. Smith CD: Cysts and sinuses of the neck. In O’Neill JA, Rowe MI, Grosfeld JL, et al (eds): Pediatric Surgery, 5th ed. St. Louis, Mosby, 1998, pp 757-771.
6. Telander RL, Filston HC: Review of head and neck lesions in infancy and childhood. Surg Clin North Am 72:1429-1447, 1992. Medline Similar articles

6. Should patients with hepatoblastoma receive preoperative chemotherapy to shrink the tumors?

Show answer
Preoperative chemotherapy does shrink tumors, resulting in easier hepatic resection and lower surgical morbidity. This benefit must be weighed against the considerable toxicity of chemotherapeutic agents.
KEY POINTS: ABDOMINAL TUMORS

1. The most common malignant solid abdominal tumors in children are neuroblastomas, Wilms’ tumor, and hepatoblastomas.
2. In neuroblastomas, age at presentation is the major prognostic factor.
3. Hepatoblastomas usually occur in infants and young children, whereas hepatocellular carcinomas usually occur in children older than 10 years.

References
BIBLIOGRAPHY
1. Caty MG, Shamberger RC: Abdominal tumors in infancy and childhood. Pediatr Clin North Am 40:1253-1271, 1993. Medline Similar articles
2. Herrera JM, Krebs A, Harris P, Barriga F: Childhood tumors. Surg Clin North Am 80:747-760, 2000. Medline Similar articles
3. Reynolds M: Pediatric liver tumors. Semin Surg Oncol 16:159-172, 1999. Medline Similar articles Full article
4. Shamberger RC, Guthrie KA, Ritchey ML, et al: Surgery related factors and local recurrence of Wilms’ tumor in National Wilms’ Tumor Study 4. Ann Surg 229:292-297, 1999. Full article
5. Shimada M: Tumors of the neuroblastoma group. Pathology 2:43-59, 1993.
6. Stocker JT: Hepatic tumors in children. Clin Liver Dis 5:259-281, 2001. Medline Similar articles

1. What is the most common type of congenital diaphragmatic hernia (CDH)?

Show answer
Congenital abnormalities of the diaphragm include a posterolateral defect (Bochdalek hernia), an anteromedial defect (Morgagni hernia), or the eventration (central weakening) of the diaphragm. The Bochdalek hernia is the most common variant and generally occurs on the left (80%). Approximately 20% occur on the right, and < 1% are bilateral.

2. What signs and symptoms suggest CDH?

Show answer
Neonatal respiratory distress is the most common manifestation of CDH caused by associated lung maldevelopment. At birth or shortly thereafter, the infant develops severe dyspnea, retractions, and cyanosis. On physical examination, breath sounds are diminished on the ipsilateral side, heart sounds can be heard more easily in the contralateral chest, and the abdomen is scaphoid because of the herniation of abdominal viscera into the chest. Mediastinal shift may result impairing venous return and cardiac output.

3. How is the diagnosis confirmed?

Show answer
A chest radiograph demonstrates multiple loops of air-filled intestine in the ipsilateral thorax. If a chest radiograph is obtained before entry of significant amounts of air into the bowel, a confusing pattern of mediastinal shift, cardiac displacement, and opacification of the hemithorax may be observed. Insertion of a nasogastric tube followed by repeat chest radiograph often demonstrates the tube (i.e., stomach) in the chest and confirms the diagnosis.

4. Are other anomalies associated with CDH?

Show answer
Fifty percent of infants with CDH have associated anomalies. Fewer than 10% of patients with multiple major concurrent anomalies survive. Excluding intestinal malrotation and pulmonary hypoplasia, cardiac anomalies (63%) are the most frequent, followed by genitourinary (23%), gastrointestinal (17%), central nervous system (14%), and other pulmonary (5%) anomalies.

5. What therapeutic measures should be initiated before transport or operation?

Show answer
Perhaps the easiest and most effective palliative intervention is decompression of the stomach with a nasogastric tube, which prevents further distention of the bowel and lung compression. Endotracheal intubation permits adequate ventilation and oxygenation. Ventilatory pressures are kept low (< 30 mmHg), and the infant is ventilated at a rapid rate (40-60 breaths/min) to avoid barotrauma. Venous access and fluid resuscitation complete preliminary resuscitation.

6. What is the “honeymoon period”?

Show answer
The honeymoon period describes the interval of time in which a neonate demonstrates adequate oxygenation and ventilation in the absence of maximal medical therapy. Regardless of subsequent deterioration, a honeymoon period suggests that pulmonary function is compatible with survival.
7. Describe the operative approach. Show answer

CDH results in a physiologic derangement of the lungs that is not reversed by surgical reconstruction of the diaphragm. Thus, repair of CDH is not a surgical emergency. The infant must be stabilized before surgical repair is attempted. A transabdominal approach allows reduction of the herniated abdominal viscera from the chest, repair of the diaphgramatic defect without obstructed vision or tension, correction of malrotation, and stretching of the abdominal cavity or creation of a ventral hernia with a prosthetic patch if the reduced viscera are not easily accomodated in the abdomen.

8. What is the most feared complication of diaphragmatic hernia?

Show answer
The most feared complication is persistent fetal circulation (PFC). In CDH, one or both lungs are hypoplastic, the pulmonary vascular bed is reduced, and the pulmonary arteries exhibit thickened muscular walls that are hyperreactive. Newborns with CDH are particularly prone to the development of pulmonary hypertension. PFC arises from a sustained increase in pulmonary artery pressure. Blood is shunted away from the lungs, and the unoxygenated blood is diverted to the systemic circulation (right-to-left shunt) through the patent ductus arteriosus and patent foramen ovale. PFC results in hypoxemia, profound acidosis, and shock. PFC is triggered by acidosis, hypercarbia, and hypoxia, all potent vasoconstrictors of the pulmonary circulation.

9. Is PFC correctable? If so, how?

Show answer
Yes. Various strategies are used to prevent or reverse PFC:

1. Monitoring: Oximetry or arterial sampling (preductal in the right upper extremity; postductal in the lower extremity) permits early detection of shunting of unoxygenated blood to the systemic circulation.
2. Ventilation: Hypercarbia is corrected by mechanical ventilation; adequate sedation; and, if necessary, pharmacologic paralysis.
3. Oxygenation: Hypoxemia is corrected by adequate ventilation and high concentrations of inspired oxygen (generally FiO2 = 100%).
4. Resuscitation: Metabolic acidosis is managed by restoring adequate tissue perfusion (intravenous fluids or blood, inotropes, and sodium bicarbonate).
5. Rescue: Salvage therapies include administration of pulmonary vasodilators via the ventilatory circuit (nitric oxide) or systemic circulation (priscoline, prostaglandin E2), high-frequency ventilation, and extracorporeal membrane oxygenation (ECMO).

10. What is the survival rate for patients with CDH?

Show answer
The overall survival rate is 60%. The major determinants of survival are the degree of pulmonary hypoplasia and associated major congenital anomalies. Among infants surviving the early newborn period without significant lung dysfunction, the survival rate approaches 100%.

11. Does in utero intervention have a role in the treatment of patients with CDH?

Show answer
To date, fetal surgery for CDH remains experimental. In a prospective trial reported in 1997, the results of intrauterine repair of CDH were compared with conventional postnatal surgery with similar outcome. The investigators concluded that because open fetal surgery does not improve survival or outcome, prenatally diagnosed CDH should be treated postnatally.

References
BIBLIOGRAPHY
1. Clark RH, Hardin WD, Hirschl RB, et al: Current surgical management of congenital diaphragmatic hernia: A report from the congenital diaphragmatic hernia study group. J Pediatr Surg 33:1004-1009, 1998. Medline Similar articles
2. Fauza DO, Wilson JM: Congenital diaphragmatic hernia and associated anomalies: Their incidence, identification, and impact on prognosis. J Pediatr Surg 29:1113-1117, 1994. Medline Similar articles
3. Harrison MR, Adzick NS, Bullard KM, et al: Correction of congenital diaphragmatic hernia in utero VII: A prospective trial. J Pediatr Surg 32:1637-1642, 1997. Medline Similar articles Full article
4. Nobuhara KK, Lund DP, Mitchell J, et al: Long-term outlook for survivors of congenital diaphragmatic hernia. Clin Perinatol 23:873-887, 1996. Medline Similar articles
5. Weber TR, Kountzman B, Dillon PA, et al: Improved survival in congenital diaphragmatic hernia with evolving therapeutic strategies. Arch Surg 133:498-503, 1998.

1. What are tracheoesophageal fistula (TEF) and esophageal atresia (EA)?

Show answer
The trachea and esophagus appear as a ventral diverticulum arising from the primitive foregut during the third week of gestation. The trachea and esophagus undergo separation by the ingrowth of ectodermal ridges during the fourth week of gestation. Failure of separation results in anomalous connection of the trachea to the esophagus (i.e., TEF) with or without incomplete formation of the esophagus (i.e., EA).

2. Describe the three most common variants and the relative incidence of each type

. Show answer

* Proximal EA with distal TEF (”proximal pouch with distal fistula”): 85%
* Isolated EA: 10%
* TEF without EA (”H fistula”): 5%

3. What other anomalies occur with tracheoesophageal malformations?

Show answer
TEF and EA result from an insult during the critical phase of embryogenesis (3-8 weeks’ gestation). Up to 70% of infants with tracheoesophageal malformations suffer one or more concomitant anomalies. Cardiovascular anomalies are the most prevalent (35%), followed by anomalies of the gastrointestinal (24%), genitourinary (20%), skeletal (13%), and central nervous (10%) systems. Twenty-five percent of infants born with tracheoesophageal malformation have one or more components of the VACTERL association (see question 2 in chapter 84).

4. Does the presence of other anomalies alter management and outcome?

Show answer
Healthy infants without concomitant anomalies generally undergo early repair with a nearly 100% survival rate, whereas infants who are severely premature or have life-threatening anomalies typically undergo delayed repair. Infants with lethal anomalies, such as trisomy 18, receive palliative care only.

5. Describe the clinical presentation, diagnosis, and preoperative management of patients with EA with distal TEF.

Show answer
Early in the newborn period, affected infants demonstrate excessive salivation (i.e., inability to swallow secretions), choking, or regurgitation with feeding (i.e., inability to swallow feeds). Respiratory distress quickly ensues because of aspiration of secretions or feeds from the esophageal pouch and reflux of gastric acid into the airways and lungs via the distal TEF. A nasogastric tube cannot be advanced into the stomach. The radiograph demonstrates a blind-ending proximal esophageal pouch and an air-filled stomach caused by the anomalous connection of the distal esophagus to the airway. The infant is maintained in a semi-upright position with sump catheter drainage of the proximal esophageal pouch to minimize contamination of the lungs either because of aspiration or reflux.

6. Describe the clinical presentation, diagnosis, and preoperative management of isolated EA.

Show answer

Isolated EA is associated with excessive salivation, choking, and regurgitation of feeds. The inability to pass a nasogastric tube into the stomach and a gasless abdomen apparent on radiograph suggests the diagnosis. Preoperative management is directed to the identification of associated anomalies and determination of gap length. Sump catheter drainage of the proximal esophageal pouch is maintained to minimize aspiration. Gastrostomy is generally performed within the first 24 hours of life to permit feeding and assessment of the distal esophageal length. Typically, infants with EA undergo delayed repair to permit growth of the distal esophagus and reduction of gap distance.

7. Describe the clinical presentation, diagnosis, and preoperative management of TEF without EA.

Show answer
These infants demonstrate repeated choking or cyanotic spells with feeding caused by the reflux of feeds from the esophagus to the lungs via the anomalous tracheoesophageal connection. Older infants and children may present with recurrent bouts of pneumonia or unexplained reactive airway disease resulting from the intermittent contamination of the lungs via the fistula. Video esophagography and bronchoscopy are used to demonstrate the fistula.

8. How are tracheoesophageal malformations corrected surgically?

Show answer
Surgical treatment entails restoration of esophageal continuity and elimination of the pathologic connection of the esophagus to the airway. Correction of EA with or without TEF requires thoracotomy, with or without ligation of TEF, and end-to-end esophageal anastomosis. The first successful procedure was performed by Cameron Haight in 1941. At 5-7 days after surgery, an esophagogram is performed; if no leak is visualized, oral feedings are started and the pleural drain is removed.
TEF without EA is approached via a cervical incision, avoiding thoracotomy. The fistulous tract is divided and healthy tissue is interposed to prevent recurrence.

9. What are the early and late complications of surgical repair?

Early complications

Early complications are related to the basic surgical principles of wound healing. Anastomotic disruption generally results from poor blood supply and tension.
Late complications

Most strictures (50%) respond to one to three dilatations performed in the first 6 months of life. Refractory strictures require identification of associated gastroesophageal reflux (GER), which may worsen stricture formation. The frequency of GER appears related to gap length (i.e., the greater the gap distance, the greater the risk of significant GER).
KEY POINTS: TRACHEOESOPHAGEAL MALFORMATIONS

1. The three most common variants are proximal esophageal atresia (EA) with distal tracheoesophageal fistula (TEE), isolated EA, and TEF without EA.
2. Early in the newborn period, affected infants demonstrate excessive salivation, choking, or regurgitation with feeding.
3. Surgical treatment entails restoration of esophageal continuity and elimination of the pathologic connection of the esophagus to the airway.

References
BIBLIOGRAPHY
1. Brown AK, Tam PK: Measurements of gap length in esophageal atresia: A simple predictor of outcome. J Am Coll Surg 182:41-45, 1996. Medline Similar articles Full article
2. Dunn JC, Fonkalsrud EW, Atkinson JB: Simplifying the Waterston’s stratification of infants with tracheoesophageal fistula. Am Surg 65:908-910, 1999. Medline Similar articles
3. Saing H, Mya GH, Cheng W: The involvement of two or more systems and the severity of associated anomalies significantly influence mortality in esophageal atresia. J Pediatr Surg 33:1596-1598, 1998. Similar articles Full article
4. Somppi E, Tammela O, Ruuska T, et al: Outcome of patients operated on for esophageal atresia: 30 years’ experience. J Pediatr Surg 33:1341-1346, 1998.
5. Spitz L: Esophageal atresia: Past, present, and future. J Pediatr Surg 31:19-25, 1996. Medline Similar articles Full article
6. Torfs CP, Curry CJ, Bateson TF: Population-based study of tracheoesophageal fistula and esophageal atresia. Teratology 52:220-232, 1995. Medline Similar articles
7. Tovar JA, Diez Pardo JA, Murcia J, et al: Ambulatory 24-hour manometric and pH metric evidence of permanent impairment of clearance capacity in patients with esophageal atresia. J Pediatr Surg 30:1224-1231, 1995.

1. What is imperforate anus?

Show answer
It is a congenital defect in which the opening of the anus is absent or misplaced, usually fistulizing anteriorly to the perineum or genitourinary (GU) tract. Anorectal malformations range from slight anterior malpositioning of the anus to complex cloacal deformities. Children with anorectal malformations commonly have other congenital anomalies, such as the VACTERL association.

2. What is the VACTERL association?

Show answer

V Vertebral defects
A Anorectal malformations
C Cardiac anomalies
T Tracheoesophageal fistula
E Esophageal atresia
R Renal anomalies
L Limb defects

The incidence of renal anomalies increases with the severity of the imperforate anus-from 10% with low lesions to 75% with high lesions.

3. How do you determine the severity of the defect in boys?

Show answer
The key is whether the boy has a high or low lesion. Low lesions are characterized by a fistula to the perineum somewhere along the midline raphe between the anus and the urethral meatus. After 24 hours, most infants with low lesions demonstrate meconium at the fistula. Other signs of a low lesion include white “pearls” along the raphe or a raised loop of skin, the so-called bucket-handle deformity. Boys with high lesions typically have flat buttocks without a good buttocks crease and may have meconium at the urethral meatus or apparent on urinalysis.

4. How is the lesion assessed in girls?

Show answer
Most affected girls (> 90%) have a rectovestibular or rectovaginal fistula, which usually can be determined by careful perineal examination. Girls with cloacal deformities (i.e., one orifice) have a high incidence of GU obstruction such as hydrocolpos or bladder obstruction. In low lesions, the anal opening is displaced anteriorly on the perineum. The normal location of the anus is halfway between the vaginal orifice and the coccyx.

5. How are infants with anorectal malformations treated?

Show answer
Infants with high lesions should be managed initially with a sigmoid colostomy and later with a pull-through procedure called posterior sagittal anorectoplasty. Infants with low lesions usually can be managed with immediate anoplasty or dilatation and delayed repair.

6. What is a posterior sagittal anorectoplasty (PSARP)?

Show answer
PSARP is a procedure performed through a longitudinal incision in the midline of the perineum, which permits visualization of the pelvic musculature and sphincters and clear exposure of the rectum and fistula. After closure of the fistula, the rectum is repositioned within the sphincteric muscle complex, and a neoanus is created.

7. What are the results after surgical reconstruction?

Show answer
Continence, defined as voluntary bowel movements with no soiling, depends on the type of lesion. Continence approaches 100% for low lesions but is rare with the highest lesions such as cloaca deformities in girls or bladder-neck fistulas in boys. Constipation is present in almost 50% of patients but is more frequent with the simpler defects.
KEY POINTS: IMPERFORATE ANUS

1. Imperforate anus is a congenital defect in which the opening of the anus is absent or misplaced, usually fistulizing anteriorly to the perineum or genitourinary tract.
2. Infants with high lesions should be managed initially with a sigmoid colostomy and later with a pull-through procedure called posterior sagittal anorectoplasty.
3. Infants with low lesions usually can be managed with immediate anoplasty or dilatation and delayed repair.

References
BIBLIOGRAPHY
1. deVries PA, Pena A: Posterior sagittal anorectoplasty. J Pediatr Surg 17:638-643, 1982. Medline Similar articles
2. Jones NM, Humphreys MS, Goodman TR, et al: The value of anal endosonography compared with magnetic resonance imaging following the repair of anorectal malformations. Pediatr Radiol 33:183, 2003. Medline Similar articles
3. Kluth D, Lambrecht W: Current concepts in the embryology of anorectal malformations. Semin Pediatr Surg 6:180-186, 1997. Medline Similar articles
4. Pena A: Anorectal malformations. Semin Pediatr Surg 4:35-37, 1995. Medline Similar articles
5. Pena A, Hong A: Advances in the managemant of anorectal malformations. Am J Surg 180:370-376, 2000.
6. Sarin YK, Sinha A, Gupta A: High anorectal malformation in boys: Need for clarity of definition and management. J Pediatr Surg 37:1637, 2002. Medline Similar articles

1. What signs or symptoms suggest intestinal obstruction in the neonate?

Show answer
Signs and symptoms vary according to the level of obstruction. Proximal intestinal obstruction leads to the early onset of bilious emesis, generally with minimal abdominal distention. In contrast, neonates with distal intestinal obstruction present after the first day of life with bilious vomiting and pronounced abdominal distention. Bilious emesis should always be interrogated further in infants and children.

2. What is the differential diagnosis of intestinal obstruction in neonates?

Show answer
Look for an anal opening, which eliminates the diagnosis of imperforate anus. Next obtain an abdominal radiograph. The extent of gaseous distention of the bowel implicates a proximal or distal bowel obstruction. No attempts should be made to distinguish small from large bowel obstruction.

3. When are contrast studies of the gastrointestinal (GI) tract indicated? Show answer
If peritonitis or pneumoperitoneum is present, proceed to exploratory laparotomy without delay. Malrotation with volvulus must be distinguished from the other cause of congenital duodenal obstruction (duodenal atresia). In this setting, upper GI is the study of choice. In volvulus, the upper GI demonstrates distention of the proximal duodenum, corkscrewing of the distal duodenum, and limited or no progression of contrast into the distal bowel. Conversely, duodenal atresia appears as a blind ending pouch in the first or second portion of the duodenum. Contrast enema is generally the preferred study in all other forms of neonatal intestinal obstruction.

4. Describe intestinal atresia.

Show answer
Atresia can occur anywhere in the GI tract: duodenal (50%), jejunoileal (45%), or colonic (5%). Duodenal atresia arises from a failure of recanalization during the 8th-10th week of gestation; jejunoileal and colonic atresia are caused by an in utero mesenteric vascular accident.

5. Distinguish duodenal atresia from other forms of intestinal atresia.

Show answer
Duodenal atresia is characterized by the onset of bilious vomiting (85% of atresia distal to the ampulla of Vater) within the first day of life; significant abdominal distention is absent. Approximately 25% of affected infants have trisomy 21. The abdominal radiograph demonstates a “double bubble” caused by the distended stomach and first or second portions of duodenum. Surgical correction is performed by duodenoduodenostomy.
Jejunoileal atresia produces bilious vomiting at 2-3 days of life with moderate to severe abdominal distention. The abdominal radiograph shows dilated loops of bowel with air-fluid levels. Barium enema reveals a microcolon and no reflux of contrast into the dilated bowel. Associated anomalies are uncommon. Surgical correction involves end-to-end anastomosis with or without limited intestinal resection.
Colonic atresia, similar to jejunalileal atresia, is associated with the late onset of bilious vomiting, no passage of meconium, and moderate to severe abdominal distention. The abdominal radiograph reveals dilated loops of bowel with air-fluid levels suggesting distal intestinal obstruction. Barium enema demonstrates a microcolon with a cutoff observed in a proximal colonic segment. Twenty percent of affected infants suffer an associated anomaly of the heart, musculoskeletal system, abdominal wall, or GI tract. Surgical management includes limited colonic resection with primary anastomosis.

6. Describe malrotation with midgut volvulus.

Show answer
During the 6th-12th week of gestation, the intestine undergoes evisceration, growth, return to the abdominal cavity, and counterclockwise rotation with fixation. Malrotation is an error in both rotation and fixation. Abnormal fixation and a narrow-based mesentery predispose to twisting of the midgut on its blood supply (superior mesenteric artery), vascular occlusion (strangulation), and obstruction (malrotation with midgut volvulus). Typically, a previously well neonate or child without a history of surgery presents with bilious vomiting, abdominal distention, and variable degrees of shock. If the infant is acutely ill, no further studies are needed and surgical exploration is indicated. If the diagnosis is in question and the infant is stable, an upper GI study, not a barium enema, is performed. Surgical treatment entails four parts: (1) division of abnormal peritoneal bands, (2) correction of malrotation, (3) restoration of a broad-based mesentery, and (4) appendectomy because of the location of the cecum in the right upper quadrant.

7. Is midgut volvulus a surgical emergency?

Show answer
Yes! The risk of strangulation caused by the rotational anomaly and abnormal peritoneal bands implies a surgical emergency. Delay places the infant at risk of losing the entire midgut and potentially dying.

8. What is meconium ileus (MI)?

Show answer
MI is the obstruction of the terminal ileum by highly viscid, tenacious meconium. MI is a complication of cystic fibrosis (CF). Fifteen percent of neonates with CF present with MI. The combination of hyperviscous mucus secreted by the abnormal intestinal glands and pancreatic insufficiency leads to abnormal meconium and obstructs the lumen of the terminal ileum. Symptoms of feeding intolerance, bilious emesis, and abdominal distention begin in the second to third days of life. Unlike most forms of neonatal intestinal obstruction, surgery is reserved for patients refractory to nonoperative treatment or complex MI (atresia, volvulus, perforation). Sixty percent of infants with simple MI can be treated successfully with Gastrografin enemas and rectal irrigation. If an operation is indicated, the objective is to remove the obstructing meconium by limited resection or enterostomy with evacuation of the meconium and irrigation of the distal bowel.

9. What is Hirschsprung’s disease?

Show answer
In this disease, the intestine is innervated by cells originating in the neural crest. During the 5th-12th week of gestation, neural crest cells migrate in a craniocaudal direction and disperse within the wall of the intestine (intermuscular, to Auerbach’s plexus; submucosal, to Meissner’s plexus). Hirschsprung’s disease arises from the failure of normal enteric innervation. The bowel remains in a contracted, spastic state and produces a functional rather than a true mechanical obstruction. Abdominal distention, feeding intolerance, and delayed or absent meconium within the first 48 hours of life are the presenting findings in infants. Older patients suffer chronic constipation, abdominal distention, and failure to thrive. Because the disease always affects the most distal bowel (80-85% rectosigmoid) with a variable involvement of proximal bowel, barium enema demonstrates the characteristic radiographic appearance of a spastic, contracted rectum with dilated proximal bowel. Suction rectal biopsy documenting the absence of ganglion cells and presence of nerve hypertrophy confirms the diagnosis. Surgical correction is performed by excision of the aganglionic (distal colorectal) segment and coloanal anastomosis.

10. What is intussusception? What are the therapeutic options?

Show answer
Intussusception is the invagination of proximal bowel (intussusceptum) into the distal bowel (intussuscipien). Swelling, vascular compromise, and obstruction follow. Nearly two thirds of cases occur in the first 2 years of life. The cause is thought to be a result of lymphoid hyperplasia in the terminal ileum after viral infection. The diagnosis should be suspected in previously well infants, 6-9 months of age, with vomiting, crampy abdominal pain, and bloody stools. Barium or air enema is both diagnostic and therapeutic. Injection of contrast demonstrates colonic obstruction with no reflux into the proximal bowel. Controlled hydrostatic reduction with barium or air is successful in 90% of cases. If hydrostatic reduction is unsuccessful or in children with peritonitis, operative reduction is indicated. The risk of recurrent intussusception is 5% for either radiographic or surgical reduction.

11. What examples of neonatal obstruction can escape early detection and present later in life?

Show answer
Although most conditions are identified within the first week to month of life, lesions other than atresia may be identified in children and even adults.
Duodenal stenosis. Unlike duodenal atresia, stenosis results in narrowing but not complete obstruction of the duodenum. Thus, infants fed formula or pureed foods may not become symptomatic until childhood. Children with intermittent abdominal pain and symptoms of gastric outlet obstruction require an upper GI study, particularly if they have trisomy 21.
Malrotation. One third of patients with malrotation are identified after the first month of life. Children present with bilious emesis and intermittent abdominal pain, and malrotation is generally identified by an upper GI series. Malrotation with midgut volvulus should be suspected in any ill child with signs of intestinal obstruction and no history of abdominal surgery.
Hirschsprung’s disease. One third of patients are diagnosed after the first year of life. A long history of constipation refractory to therapy mandates rectal biopsy, particularly in patients with trisomy 21.
Intussusception. One third of cases occur after age 2 years. A pathologic lead point (i.e., polyp, tumor, hematoma, Meckel’s diverticulum) is present in one third of older patients.

References
BIBLIOGRAPHY
1. Aquino A, Domini M, Rossi C, et al: Correlation between Down’s syndrome and malformation of pediatric surgical interest. J Pediatr Surg 33:1380-1382, 1998. Medline Similar articles
2. Daneman A, Alton DJ, Ein S, et al: Perforation during attempted intussusception reduction in children-a comparison of perforation with barium and air. Pediatr Radiol 25:81-88, 1995. Medline Similar articles
3. Godbole P, Stringer MD: Bilious vomiting in the newborn: How often is it pathologic? J Pediatr Surg 37:909-911, 2002.
4. Long FR, Kramer SS, Markowitz RI, Taylor GE: Radiographic patterns of intestinal malrotation in children. Radiographics 16:547-560, 1996. Medline Similar articles
5. Maxson RT, Franklin PA, Wagner CW: Malrotation in the older child: Surgical management, treatment, and outcome. Am Surg 61:135-138, 1995. Medline Similar articles
6. Reding R, de Ville de Goyet J, Gosseye S, et al: Hirschsprung’s disease: A 20 year experience. J Pediatr Surg 32:1221-1225, 1997. Full article

1. What is pyloric stenosis?

Show answer
Hypertrophic pyloric stenosis (HPS) is idiopathic thickening and elongation of the pylorus that produces gastric outlet obstruction. HPS is the most common surgical cause of nonbilious vomiting in infants. Offspring of an affected parent have an increased incidence of HPS (10%); the highest rate (20%) occurs in boys born to affected mothers.

2. Describe the typical presentation of HPS.

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The typical presentation is a healthy infant who initially fed normally but who presents at age 2-6 weeks with a history of “projectile” vomiting. The emesis is nonbilious. After vomiting, the infant appears hungry and will refeed immediately. With time, the infant becomes dehydrated and, if allowed to progress, malnutrition follows.

3. What are the physical findings?

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Affected infants suffer some degree of dehydration. The abdomen is nondistended and soft. A palpable pyloric tumor, known as the “olive,” confirms the diagnosis. An olive is palpable in 50% of patients. Associated findings are rare, but mild jaundice occurs in 5% of infants because of reduced glucuronyl transferase activity.

4. How is the diagnosis confirmed?

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Ultrasonographic criteria include pyloric diameter > 1.4 cm, wall width > 4 mm, and pyloric channel length > 1.6 cm. Alternatively, a barium upper gastrointestinal (UGI) examination may be used to confirm the diagnosis (gastric outlet obstruction, pyloric channel narrowing). Current analyses suggest that UGI is the most cost-effective initial radiologic diagnostic test because, unlike ultrasound, alternative causes of nonbilious vomiting (e.g., gastroesophageal reflux, malrotation, duodenal stenosis) can be identified.

5. Describe the likely electrolyte abnormalities.

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Electrolyte levels are often normal, but long-standing vomiting will eventually result in hypokalemic, hypochloremic metabolic alkalosis because of the loss of gastric acid (HCl). Earlier consideration of the diagnosis has led to a significant reduction in this classic electrolyte abnormality at presentation. Dehydration is corrected with either 0.9% NaCl or, in less severe cases, 0.5% NaCl with 30 mEq/L KCl. After dehydration and electrolytes are corrected, pyloromyotomy is performed.

6. What procedure is recommended for the correction of HPS?

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The Fredet-Ramstedt pyloromyotomy is recommended. A superficial incision is made longitudinally over the pyloric muscle in an avascular area, and the muscle fibers are fractured to expose the underlying mucosa. At the conclusion of the pyloromyotomy, the gastric mucosa should bulge upward into the cleft, and the pyloric muscle walls should move independently of one another. Air is injected into the stomach via the nasogastric tube to identify inadvertent mucosal perforation. Pyloromyotomy may be performed either via a transverse incision in the right upper quadrant (i.e., an open procedure) or via three small (3-mm) incisions in the epigastrium (i.e., a laparoscopic procedure). The results of open and laparoscopic pyloromyotomy appear equivalent.

7. What should be done if a perforation is identified?

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The mucosa should be closed with several fine sutures and covered with an omental patch. If the mucosal injury is too extensive, the myotomy should be closed with sutures and a second, parallel myotomy should be made at 45-180° from the original myotomy.

8. When can postoperative feeding begin?

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Small-volume feedings are started after the infant has recovered from anesthesia (2-3 hours) and advanced to goal. Small amounts of vomiting are common (20%), but most infants achieve full feeds within 24 hours postoperatively. Incomplete pyloromyotomy is uncommon (< 1%) and is not considered unless symptoms of gastric outlet obstruction persist for 7-10 days after surgery.

9. Describe several hypotheses about the pathogenesis of HPS.

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Recent studies of the abnormal pyloric complex demonstrate improper innervation of pyloric smooth muscle, excessive contraction of circular pyloric smooth muscle (decreased nitric oxide synthase), increased extracellular matrix proteins (collagen), and increased expression or local synthesis of growth hormones (i.e., insulin-like growth factor-1, transforming growth factor beta-1, platelet derived growth factor).

References
BIBLIOGRAPHY
1. Campbell BT, McLean K, Barnhart DC, et al: A comparison of laparoscopic and open pyloromyotomy at a teaching hospital. J Pediatr Surg 37:1068-1071, 2002. Medline Similar articles Full article
2. Chen EA, Luks FI, Gilchrist BF, et al: Pyloric stenosis in the age of ultrasonography: Fading skills, better patients? J Pediatr Surg 31:829-830, 1996. Full article
3. Garza JJ, Morash D, Dzakovic A, et al: Ad libitum feeding decreases hospital stay for neonates after pyloromyotomy. J Pediatr Surg 37:493-495, 2002. Medline Similar articles Full article
4. Hulka F, Campbell JR, Harrison MW, et al: Cost-effectiveness in diagnosing infantile hypertrophic pyloric stenosis. J Pediatr Surg 32:1604-1608, 1997. Medline Similar articles Full article
5. Miozzari HH, Tonz M, von Vigier RO, et al: Fluid resuscitation in infantile hypertrophic pyloric stenosis. Acta Paediatr 90:511-514, 2001. Medline
6. Ohshiro K, Puri P: Pathogenesis of infantile hypertrophic pyloric stenosis: Recent progress. Pediatr Surg Int 13:243-252,1998. Medline Similar articles Full article