AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

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• Introduction
• RELEVANT ANATOMY
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• RELEVANT ANATOMY
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

The word atresia etymologically comes from the Greek a, which means no or without and tresis, which means orifice.

Jejunoileal atresias and stenoses are major causes of neonatal intestinal obstruction. Atresia refers to a congenital obstruction with complete occlusion of the intestinal lumen and accounts for 95% of obstructions. Stenosis, on the other hand, refers to a partial occlusion with incomplete obstruction and accounts for the remaining 5% of obstructions.¹

Intestinal atresia or stenosis can occur anywhere along the GI tract, and the anatomic location of the obstruction determines the clinical presentation. Most newborns with intestinal obstruction present with bilious emesis. Bilious vomiting in the neonate should be considered secondary to a mechanical obstruction until proven otherwise, and emergency surgical evaluation is warranted in every newborn with this symptom.

The survival of patients with intestinal obstruction has markedly improved over the last 20 years because of an improved understanding of intestinal physiology and the etiologic factors of the condition, refinements in pediatric anesthesia, and advances in surgical and perioperative care of newborns.¹

History of the Procedure

Ileal atresia has long been recognized. The first description of ileal atresia was credited to Goeller in 1684.¹ In 1911, Fockens reported the first successful surgical repair of a patient with small intestinal atresia.^{2, 1} However, the mortality rate for the surgical correction of this condition remained high for many years, even in the best pediatric surgical centers.²

In 1955, Louw and Barnard demonstrated the role of late intrauterine mesenteric vascular accidents as the likely cause of jejunoileal atresias, rather than the previously accepted theory of inadequate recanalization of the intestinal tract.³ Since that time, other factors such as in utero intussusception, intestinal perforation, segmental volvulus, and thromboembolism have also been shown to cause jejunoileal atresia.⁴ Atresias can also develop in patients with gastroschisis and in those with meconium ileus.

Frequency

The prevalence of jejunoileal atresia widely varies among different reports. In France, the prevalence is 2.25 cases per 10,000 live births.⁵ The overall prevalence of small intestinal atresia in Spain and Latin America is 1.3 cases per 10,000 live births.⁶

Intestinal atresia accounts for about one third of all cases of neonatal intestinal obstruction.⁷ In West Africa, intestinal atresia is the fourth most common cause of neonatal intestinal obstruction after anorectal malformations, Hirschsprung disease, and strangulated inguinal hernias.⁸ In an 11-year retrospective review of 500 children in India, Ranan et al found intestinal atresias to be the most common cause of intestinal obstruction in newborns and the second most common cause (11.8%) after intussusception (20.8%) in all age groups.⁹

Boys and girls are equally affected.⁷ In most studies, jejunoileal atresias seem to be more common than duodenal atresias, and colonic atresias account for the fewest number of cases.¹⁰

Unlike duodenal atresia, jejunoileal atresia associated with Down syndrome is uncommon. Patients with intestinal atresia are epidemiologically characterized by young gestational age and low birth weight, the atresia is associated with twinning, the parents are more often consanguineous compared with parents of healthy neonates, and vaginal bleeding frequently complicates the pregnancies. No correlation between jejunoileal atresia and parental age or disease has been proven.^{5, 6, 4} However, one study in France showed an increased prevalence of intestinal atresias in infants born to teenagers.⁵ Some maternal infections may be associated with ileal atresia.⁶

Etiology

Segmental differentiation of the embryonic gut starts as early as 3 weeks’ gestation. Fetal bile secretion and the swallowing of amniotic fluid begin in at 11-12 weeks’ gestation, well after revacuolization of the solid cord stage.¹ The small intestinal epithelium in humans is mature at birth. Luminal components such as amniotic fluid (before birth) and enteral nutrition (after birth) are not essential for epithelial maturation. Rather, epithelial protein expression (genetically imprinted) is crucial for nutrient absorption, epithelial defense, and repair of the small intestine.¹¹

The higher prevalence of associated congenital malformations with duodenal atresia compared with jejunoileal atresia suggests that proximal obstructions occur earlier in fetal life.^{12, 13}

Unlike duodenal atresia, many jejunoileal atresias are separated by a cordlike segment or a –V-shaped mesenteric gap. This finding and the usual finding of bile pigments and lanugo hairs distal to the atretic segment indicate that an in utero vascular accident that occurs relatively late in gestation (>11-12 weeks’ gestation) is likely the origin of these atresias, rather than failure of GI tract recanalization. A localized intrauterine vascular accident with ischemic necrosis of the bowel and subsequent reabsorption of the affected segment is the favored theory.^{14, 3, 2, 1, 15}

The localized nature of a vascular insult explains the low prevalence (10%) of coexisting conditions. Intestinal atresia associated with in utero intussusception or perforation, malrotation, volvulus, internal hernias, gastroschisis, and omphalocele further corroborates a vascular event as the etiology of most jejunoileal atresias.^{16, 15}

Sweeney et al examined 38 patients with jejunal atresia and 45 patients with ileal atresia at the Children's Research Center in Dublin, Ireland.¹³ Compared with patients with ileal atresia, patients with high jejunal atresia had a higher rate of associated congenital malformations (42% vs 2%), had a higher rate of multiple or apple-peel (type IIIb) atresias (53% vs 9%), and had a higher mortality rate. These results suggest that jejunal atresia may also develop from a malformative process.

In a collaborative study in France, Gaillard et al reviewed 102 cases from 42 induced abortions and 22 stillborns, as well as surgical findings in 38 neonates.¹⁷ Abnormalities such as meconium ileus (associated with cystic fibrosis) and chromosomal aberrations (eg, Down syndrome) were present during the second trimester of gestation. Intestinal atresia and stenosis were detected in the third trimester of pregnancy and were associated with ischemic conditions.

Most infants with this condition have only a single atretic segment. However, multiple atresias have been described in infants of mothers who ingested ergotamine and caffeine, or pseudoephedrine alone or in combination with acetaminophen during pregnancy.^{18, 19} Other vasoconstrictive factors such as cocaine abuse and smoking during pregnancy have also been associated with increased risk for the development of intestinal atresia.¹⁹ Also, the risk is higher in patients with graft versus host disease and immunosuppression and in those with malformative processes that are likely due to autosomal recessive transmission.^{20, 21}

Multiple intestinal atresias have been reported in rare association with pyloric atresia and pylorocholedochal fistula.²²

Familial cases of various types of atresia have been well described.²³ Familial type I jejunal atresia affected 3 members from 2 generations in one family. Proximal atresia was associated with renal dysplasia. Knowledge of the familial form of the disease indicates that most cases of jejunoileal atresia actually result from disruption of a normal embryologic pathway, most likely the development of the superior mesenteric artery and its branches. They should be considered to be true embryologic malformations rather than acquired lesions.²³

This association is presumably an autosomal dominant condition.²⁴ Matsumoto et al reported a case in Japan and reviewed the literature, finding 6 other cases of small intestinal atresia occurring in twins.²⁵ All published cases except one involved identical twins. Three pairs of twins had different types of atresia, and 4 pairs did not have any other anomalies. The other members of these families were not affected; this finding suggested that such cases may be due to environmental influences during gestation.

Pathophysiology

Dalla Vecchia et al performed a 25-year retrospective review and found 277 neonates with intestinal atresia.¹² The level of obstruction was duodenal in 138 patients, jejunoileal in 128, and colonic in 21. Of the 277 neonates, 10 had obstruction at more than one site. Jejunoileal atresia was associated with intrauterine volvulus (27%), gastroschisis (16%), and meconium ileus (11.7%).

In atresias of the small intestine, the jejunum and ileum are equally affected.^{7, 26 1} The proximal jejunum is the site of atresia in 31% of cases, the distal jejunum in 20%, the proximal ileum in 13%, and the distal ileum in 36%.¹ In more than 90% of patients, the atresia is single; however, multiple atresias are reported in 6-20% of cases.^{27, 1}

Heij et al performed a retrospective analysis of 21 patients with jejunal atresia and 24 with ileal atresia and found more differences than similarities between the groups (see Table).²⁸ The mean birth weight and gestational age were significantly lower in patients with jejunal atresia than in those with ileal atresia. Most jejunal atresias were multiple, whereas most ileal atresias were single. Antenatal perforation occurred frequently (10 cases) in ileal atresia but infrequently (2 cases) in jejunal atresia. The postoperative course was often prolonged, and the mortality rate increased in patients with jejunal atresia, among whom 3 deaths occurred (all in patients with apple-peel deformity). By comparison, one patient with ileal atresia died.

Heij et al suggested that a difference in compliance of the bowel wall between the jejunum and ileum may explain some of their findings.²⁸ The compliant jejunal wall allows for massive dilatation with subsequent loss of peristalsis, accounting for the prolonged postoperative course and the relatively high rate of perforation in ileal atresias.

Differences Between Jejunal and Ileal Atresia^{28, 5, 1, 6, 4}

The maximal dilatation of the proximal segment occurs at the point of obstruction. This segment is commonly aperistaltic, of questionable viability, or both.² Grosfeld et al have modified Louw’s original classification into the following most commonly used description of intestinal atresia:²⁶

• Type I – Membrane
• Type II – Blind ends joined by fibrous cord
• Type IIIa – Disconnected blind end
• Type IIIb – Apple-peel deformity
• Type IV – Multiple, string of sausages

Stenosis

The proximal dilated intestine is in continuity with the distal nondilated bowel, and the mesentery is intact. Between these portions, a narrow, semirigid segment with a minute lumen is present. The small bowel length is normal. This lesion might simulate an atresia type I (see Media file 4).

Atresia type I (membrane)

This type is a mucosal (septal) atresia with an intact bowel wall. The proximal dilated intestine is continuous with the distal narrow one. The mesentery is intact, and the intestinal length is normal. The pressure generated on the internal membrane may elongate it as a windsock, giving a conical appearance to the transition. The distal intestine is collapsed (see Media file 5) but may contain meconium.

Atresia type II (blind ends joined by a fibrous cord)

In this type, a fibrous cord separates the proximal bowel from the distal segment. The mesentery is usually intact, but a small, V-shaped defect may be present. The length of the intestine is normal. The proximal blind pouch is grossly dilated, often aperistaltic and cyanotic. In addition, perforations have been encountered in patients who present late. Dilatation usually extends proximally 10-15 cm, after which the intestine assumes a relatively normal appearance. The distal blind pouch may be mildly distended because of retained cellular debris (as in fetal intussusception) (see Media file 6).

Atresia type III

Type III atresias seem to be the most common.^{7, 10} Intrauterine resorption of fetal gut subjected to a vascular insult explains the reduced bowel length commonly seen in this type of atresia. The distal bowel is small and decompressed.

Atresia type IIIa (disconnected blind ends)

In this type of atresia, both blind ends are completely separated without a fibrous cord between them. The atresia has a V-shaped mesenteric gap, and the intestine is shortened (see Media file 7). The proximal dilated pouch may have questionable viability and undergo torsion.

Atresia type IIIb (apple-peel deformity)

This type of atresia is also called the Christmas-tree deformity. Both intestinal segments are separated as in type IIIa, and the mesenteric defect is large. The proximal atretic segment is in the upper jejunum, near the ligament of Treitz, and the pouch is distended and lacks dorsal mesentery. The superior mesenteric artery distal to the middle colic branch is absent. The collapsed distal intestine helically encircles a small vessel (marginal artery) that arises from the ileocolic or right colic arcades, or the inferior mesenteric artery, and its vascularity may be impaired.

Type I or type II atresias may coexist in the distal segment. The intestine is always substantially shortened (see Media file 8). Many patients with this variant have low birth weight (70%) and were born premature (70%); they may also have malrotation (54%), multiple atresias, and an increased number of other associated anomalies that increase the prevalence of complications (63%) and mortality rate (54-71%).^{29, 1, 30}

Atresia type IV (multiple atresia)

Type IV atresia refers to any number and combination of atresias type I to III that simultaneously present, creating a string-of-sausages appearance (see Media file 9). A possible cause is intrauterine inflammation. However, findings of this type of atresia in family members suggest possible autosomal recessive transmission.^{31, 27, 21}

The presence of multiple GI atresias with cystic dilatation of the biliary duct is rare; the association has been described in 37 patients, with no recorded survivors in the world literature.^{24, 32} The dilatation of the bile duct seems to be due to normal drainage of bile into a closed-loop duodenal obstruction. Patients present with multiple atresias and die from short-bowel syndrome and complications related to total parenteral nutrition (TPN).

Clinical

Jejunoileal atresias can be identified on the basis of polyhydramnios present during prenatal evaluation, bilious vomiting, abdominal distension, and jaundice. Some patients may not pass meconium in the first day of life.

Clinical presentation of patients with jejunoileal atresia is as follows:

• Common characteristics
• • Polyhydramnios on prenatal ultrasound (28%)
  • Prematurity (35%)
  • Low birth weight (25-50%)
• Classic signs
• • Bilious emesis that warrants emergent surgical evaluation (most patients)
  • Abdominal distention (in distal atresias)
  • Jaundice (32%)
  • Failure to pass meconium in the first 24 hours (Rule out Hirschsprung disease. Passage of meconium does not rule out intestinal atresia.)
• Signs of continuous fluid loss
• • Dehydration, manifested by sunken fontanel and dry membranes
  • Decreased urine output (best clinical indication of tissue perfusion)
  • Tachycardia
  • Decreased pulse pressure 
  • Low-grade fever
  • Neurological involvement, manifested by irritability, lethargy, or coma

Patients are frequently premature (35%).⁵ One third of infants with jejunal atresia, one fourth of those with ileal atresia, and more than one half of those with multiple atresias have low birth weight.¹

Most patients present with bilious emesis, which indicates that the obstruction is distal to the ampulla of Vater.

The patient's pulse, respiratory rate, blood pressure, and temperature are usually initially within the reference range. As the patient loses fluid into the bowel and by vomiting, diminished plasma volume is reflected as tachycardia, decreased pulse pressure, and sometimes low-grade fever.

Immediately after delivery, the patient appears relatively healthy. Over time, the patient develops signs of hypovolemia (sunken eyes, sunken fontanel, dry skin and mucous membranes, and prolonged capillary refill time), which are due to vomiting and intra-abdominal third-space loss secondary to the obstruction. These patients are hungry and properly suck milk; however, they cannot tolerate feedings and continue to vomit profusely. They eventually become lethargic and hyporeactive, with muscle flaccidity. They can develop skin mottling, cardiovascular instability, and neurological involvement (irritability or coma).

A proximal small-bowel obstruction results in loss of fluids that resemble gastric juice and thus produces hypokalemic and hypochloremic metabolic alkalosis. With distal small bowel obstruction, fluid losses are usually isotonic, so serum electrolytes are normal until sufficient dehydration results in metabolic acidosis, as demonstrated by tachypnea and as low serum bicarbonate and elevated serum chloride values.

Adequate tissue perfusion is evaluated by observing the patient's capillary refill time, pulse, blood pressure, and urine output. If the patient is severely dehydrated, tenting of the skin can be noted.

About 32% of infants with jejunal atresia and 20% of those with ileal atresia have jaundice, which is characteristically due to indirect hyperbilirubinemia.¹⁰

Abdominal distension is most evident in cases of ileal atresias, in which it is diffuse, as opposed to proximal jejunal atresias, in which the upper abdomen is distended and the lower abdomen is scaphoid.

Intestinal loops and their peristalsis may be seen through the thin abdominal wall of newborns.

The abdomens of these babies are usually soft, without signs of peritonitis. In utero perforations usually seal before delivery. However, an excessively dilated proximal segment may undergo torsion, necrosis, and/or perforation. In these cases, the patient appears septic and dehydrated, and the abdominal wall may be discolored.

The patient's ability to pass some meconium does not exclude intestinal atresia. Cellular debris and swallowed amniotic fluid and lanugo hairs form meconium; this formation occurs earlier in gestation than the insult that produces the atresia.

Upon laboratory examination, an elevated hematocrit level secondary to hemoconcentration due to reduced plasma and extracellular fluid volume loss may be detected. The WBC count may be either normal or elevated. Patients may present with indirect hyperbilirubinemia and the electrolyte disturbances mentioned above.

Differential diagnosis

Atresias should be distinguished from other causes of neonatal intestinal obstruction. Meticulous history taking and physical examination are the most useful elements in differentiating these conditions. Clinical settings and paraclinical studies to support the decision-making process are mentioned. The following are differential diagnoses of jejunoileal atresia and the indicated study associated with them:

• Malrotation with or without midgut volvulus – Contrast-enhanced upper-GI study
• Meconium ileus – Contrast-enhanced enema
• Intestinal duplication – Contrast-enhanced study, ultrasonography
• Internal hernia – Intraoperative examination
• Colonic atresia – Visual inspection (which reveals diffuse distension)
• Colonic aganglionosis – Rectal Biopsy
• Adynamic ileus – Examination (which reveals sepsis) and electrolyte disturbances

In patients with meconium ileus, a family history and a chloride sweat test are important. In this subgroup of patients, the viscosity of the meconium precludes the observation of air-fluid levels, and the Neuhauser sign can be revealed using radiography as a ground-glass appearance in the right lower quadrant. A contrast-enhanced enema that reveals reflux into the ileum is diagnostic.

Meconium peritonitis, due to in utero intestinal perforation, can be revealed using plain abdominal imaging. It appears as calcifications throughout the peritoneal cavity.

Patients with Hirschsprung disease are not usually premature or small for gestational age. A transition zone can be revealed using a barium enema study if enough time to develop high intraluminal pressure and proximal dilatation has passed. Rectal biopsy findings are diagnostic.

RELEVANT ANATOMY

Section 3 of 10  

• Authors and Editors
• Introduction
• RELEVANT ANATOMY
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

See Intraoperative details.

WORKUP

Section 4 of 10  

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• Introduction
• RELEVANT ANATOMY
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

Imaging Studies

• Prenatal ultrasonography
• • Intestinal atresias can be prenatally diagnosed using ultrasonography. Polyhydramnios and echogenic distended bowel loops are the characteristic findings. Polyhydramnios is present in one fourth of patients overall but it is more common in cases of high atresia (38%).^{33, 34, 30} 
  • Unfortunately, the specificity of ultrasonography is low, and only 28% of suggestive cases are confirmed after delivery.³⁴ The fetus swallows about 25-40% of the amniotic fluid in the fourth or fifth month, and the fluid is reabsorbed in the first 25-30 cm of the jejunum.³⁵ Therefore, proximal atresias are easier to diagnose than ileal or colonic atresias because the distal lesions are not usually associated with polyhydramnios.
• Plain abdominal radiography of the kidneys, ureters, and bladder (KUB)
• • A plain abdominal film should be obtained in every newborn with an intestinal obstruction.
  • Although considered pathognomonic of duodenal atresia, the double-bubble sign can be seen in very proximal jejunal atresias. The radiographic findings characteristic of jejunoileal atresia are distended bowel loops with air-fluid levels proximal to the level of the obstruction (see Media file 1). The lower the atresia is in the GI tract, the greater the number of intestinal loops that appear distended on the radiograph. Peritoneal calcifications, seen in 12% of patients, suggest meconium peritonitis, a sign of in utero intestinal perforation.
• Upper GI series
• • A contrast-enhanced upper-GI is seldom required. This study is typically performed to rule out partial obstruction or malrotation, which is present in 10% of patients with jejunoileal atresia.¹⁰
  • When performed, the study shows gastric dilatation and an enlarged small bowel up to the level of the atresia, where a blind pouch can be seen (see Media file 2). In cases of intestinal stenosis, the prestenotic segment appears dilated, a transition point is evident, and contrast material can be seen in the distal bowel.
• Barium enema study
• • The radiographic image of the colon of the newborn lacks the characteristic haustrae seen in older children. A contrast enema can be useful to distinguish large-bowel distension from small-bowel distension, to identify a site of colonic or distal ileal obstruction, to determine the presence of a microcolon, and to identify the position of the cecum; this last finding is useful in cases of abnormal rotation and fixation of the intestine (see Media file 3). Most neonates with jejunoileal atresia have an unused microcolon, except when the vascular accident leading to atresia occurs late in gestation, as in the case of idiopathic in utero intussusception.¹⁶
  • Remember that patients with meconium ileus also present with a microcolon.

Diagnostic Procedures

• When a neonate does not pass meconium in the first 24 hours of life, Hirschsprung disease should be a concern.
• In the absence of radiologic findings suggestive of atresia, suction rectal biopsy should be performed. This is done at the bedside and does not require anesthesia.

Histologic Findings

If the patient has Hirschsprung disease, rectal biopsy reveals an absence of ganglion cells and hypertrophy of the nerve bundles.¹⁵

TREATMENT

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• Introduction
• RELEVANT ANATOMY
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

Surgical therapy

The key for successful treatment of neonates with intestinal atresia is comprehensive perioperative care. This is usually best accomplished by a team that includes experienced surgeons, neonatologists, and nutritional support teams. Early diagnosis, proper preoperative stabilization, the right choice of surgical procedure, and good postoperative neonatal care are the most important considerations.

Preoperative details

Neonates tolerate surgical procedures best when they are metabolically and hemodynamically stable. Attention should be directed to prevent or correct hypothermia, hypovolemia, hypoglycemia, and hypoxemia.

The patient is admitted to the neonatal intensive care unit and restricted to nothing by mouth (NPO). The baby should be kept in a warm environment (eg, an incubator) with humidified air, and the oxygen saturation should be monitored. Vital signs should be frequently assessed. The airway is kept clear with frequent nasopharyngeal aspiration. Intubation for respiratory support in patients with severe abdominal distension or sepsis may be necessary. Baseline laboratory investigations are performed, and blood is cross-matched. Use of umbilical lines should be avoided because of the increased risk of infection and because they become suboptimal for the transverse incision for laparotomy. Specific fluid and electrolyte management of the newborn patient are beyond the scope of this chapter. Acute hypovolemia is managed with 10- to 20-mL/kg boluses of lactated Ringer solution.

An orogastric tube should be placed for gastric decompression and to avoid aspiration. Neonates are obligate nasal breathers; breathing through the mouth is a learned reflex that occurs around age 3 months. Gastric output must be replaced as well. Because urine output is the best clinical indicator of hemodynamic stability, a bladder catheter is used to ensure an output of 1-2 mL/kg/h. Before surgery, 1 mg of vitamin K is intramuscularly (IM) administered, and broad-spectrum antibiotics are intravenously (IV) administered.

Neonates lose heat more rapidly and have higher metabolic requirements than older patients. Care must be taken in keeping the metabolic demands satisfied and the baby warm at all times, including during transport to the surgical suite and during induction of anesthesia.

Intraoperative details

During anesthesia, the patient is carefully monitored. The blood loss is quantified and the intravascular volume kept adequate.

The abdomen is entered through a supraumbilical transverse incision (see Media files 10-11). The entire intestine is delivered through the incision to assess the anatomy and type of atresia and to rule out other anomalies. A perforation, if present, should be controlled at this stage before further exploration is done. The definitive way to exclude distal atresias, which occur in 6-21% of patients, is to irrigate normal sodium chloride solution into the distal pouch and to milk it caudally. If other anomalies are ruled out, the intestine is returned to the abdominal cavity while keeping the atretic segment exposed. When the intestinal length is normal, the dilated proximal pouch can be resected, by removing 10-15 cm of dilated bowel proximal to the atresia, to avoid postoperative physiologic obstruction due to lack of peristalsis. 

Instillation of normal sodium chloride solution with a 24-gauge needle through a pursestring suture into a clamped distal pouch may be useful to distend that segment and to reduce the size discrepancy between the proximal and distal intestine (see Media file 12). The proximal intestine is transected at a right angle to maximize its vascularity, whereas the distal bowel is transected obliquely and the incision is continued along the antimesenteric border as a fish mouth to equalize the size of the openings on both sides for the anastomosis (see Media file 13).³⁶

Louw et al conducted experiments that precluded the blood supply to some parts of the intestine under development.³ The authors concluded that it was likely that the blood supply to portions of the bowel adjacent to the atretic segment would be compromised, not enough to cause necrosis but sufficient to cause a functional problem with resultant defective peristalsis. Thus, they recommend resection of the blind bulbous end of the proximal intestine prior to the anastomosis. The mortality of intestinal atresia at Great Ormond Street Hospital decreased from 69% to 33%.³⁷

A 1- or 2-layer, end-to-back (end-to-oblique) anastomosis is performed. The mesenteric gap is then approximated with fine absorbable sutures by taking care to avoid kinking the anastomosis and damaging the mesenteric vessels. Patency of the anastomosis can be tested by milking intestinal air through it. The intestinal segment is then moistened with warm normal sodium chloride solution and returned to the abdominal cavity.

The abdominal wall is closed in layers with absorbable sutures.

Intestinal stenosis and type I atresias (membranes) should be treated in the same way described above. Bypass procedures are generally suboptimal because they fail to remove the abnormal intestine, and side-to-side anastomoses have the risk of creating blind loops. For membranous atresias, membrane excision with transverse enteroplasty is sometimes appropriate, particularly when membranes are present as part of multiple atresias.

Gastrostomy tubes are not routinely used, and postoperative nasogastric suction suffices for gastric decompression. This is the authors' preference. However, some authors recommend using a gastrostomy tube in a very high jejunal atresia for stomach decompression and to pass a transanastomotic tube for early postoperative enteral drip feeding (see Media file 14).² Another option for early postoperative enteral feeding is to pass a nasojejunal transanastomotic tube; however, the high incidence of nasal sores with long-term nasal tubes must be kept in mind.

When bowel length is reduced (for type III or IV atresias) and the patient is in danger of having a severely shortened intestine, an antimesenteric tapering jejunoplasty may be performed over a 26F tube by diminishing the diameter of the proximal bowel and preserving bowel length. This can be manually performed or performed using a GIA stapler and oversewing the staple line with Lembert sutures (see Media files 15-16). Some patients require repeated surgical procedures to manage functional obstruction due to an aperistaltic, dilated bowel at the site of the anastomosis.

If the need for long-term TPN is anticipated, a central venous catheter is placed. The author prefers to place the central catheter in the same anesthetic procedure, after the laparotomy.

In patients with atresia associated with gastroschisis, closure of the abdominal wall takes priority over the repair of the atresia.³⁸ Indications for primary anastomosis versus stoma formation depend on the degree of damage, the dilatation of the preatretic intestine at initial presentation, and the overall medical condition of the patient. Although primary anastomosis is preferred, it is not advisable when the vascular integrity of the intestine is questionable or when severe peritonitis or complicated meconium ileus are present. In such cases, resection of the atretic segment and enterostomy are advisable.

When multiple atresias are present, a judgment must be made about whether all atresias can be managed at the same time or whether a staged repair is necessary. In the latter case, a temporary ostomy or ostomies are used at the appropriate levels.

Grosfeld et al reported on the treatment of 128 patients with jejunoileal atresia in their 25-year review of patients at James Whitcomb Riley Hospital for Children in Indianapolis, Indiana.²⁶ Resections were performed in 97 (76%) of 128 patients (anastomosis in 45 [46%], tapering enteroplasty in 23 [24%], temporary ostomy in 29 [30%]), ostomy alone in 25 (26%), web excision in 5 (5%), and the Bianchi procedure in 1 (1%).

Postoperative details

After the procedure, the patient is transferred to the neonatal ICU. Thermoregulation with an incubator is most important. Oxygen saturation should be monitored, and maintenance fluids are administered. The gastric output is closely monitored and replaced volume for volume. Extra boluses of 10-20 mL/kg of lactated Ringer solution may be necessary to maintain urine output at 1-2 mL/kg/h. Transfusion is administered if indicated.

Glucose, hemoglobin, electrolytes, and bilirubin levels are frequently monitored during the first postoperative days, and adjustments are made accordingly. Phototherapy to avoid kernicterus is sometimes necessary.

Although the literature does not support the use of prophylactic antibiotics beyond 24-48 hours after the procedure, the authors continue antibiotic coverage for 5 days after surgery.

Enteral feedings are carefully started after signs of propulsive peristalsis occur, as indicated by clear, low-volume nasogastric output; a soft, nondistended abdomen; and evidence that the baby is passing flatus or stool.

Enteral intake can be started with most oral rehydration solutions at small rates. If tolerated, breast milk is preferable to any commercial formula. If breast milk is not available either from the mother or the milk bank, diluted or half-strength, half-volume formula can be used. The concentration and volume are progressively increased as the patient tolerates the formula. Hydrolyzed isotonic or low-osmolality formulas based on cow's milk protein are recommended for this setting.

Achieving full enteral nutritional support may take several days (mean, 5-7) or longer, even months later. In patients in whom return of intestinal function is predicted to be prolonged, centrally or peripherally delivered TPN is of prime importance.

Guidelines for TPN are well established, and the use of TPN should be judicious. Estimated nutrition goals in the first 6 months of life are approximately 100-110 kcal/kg/d and 2-3 g of protein. A complicated postoperative period increases the patient's caloric needs by 20-30% and should be taken into consideration. TPN should be advanced over 3-5 days to caloric goals, and fat intake should not be neglected. A general rule is that calories from fat (enteral, IV as intralipid formulations, or the like) should be 40% of total calories. The goal for IV fat intake for neonates is 3 g/kg/d.

Although TPN is the main adjunctive treatment for these cases, it delays intestinal adaptation and may cause cholestasis and subsequent liver damage.³⁰ Therefore, TPN should be a bridge to full enteral nutrition, and a concerted effort should be made to use it as such. As intestinal function returns, the patient is progressively weaned from parenteral to enteral nutrition until the full nutritional requirements are enterally obtained.

Graduated enteric feedings and growth hormone, glutamine, and modified diets have been used to successfully diminish TPN requirements and enhance nutrient absorption.¹² Although this feeding is being established, metabolic surveillance of patients is important. Daily laboratory workup should include a basic metabolic panel and assessment of calcium, phosphorus, and magnesium levels. Triglyceride levels should be monitored while IV fat formulations are advanced until the goal is reached. Persistent hypertriglyceridemia may reflect metabolic dysfunction and warrants further evaluation. Also, IV fat should be withheld from septic or hemodynamically unstable patients until this problem is solved.

A physiologic principle to remember, is that the longer the time that elapses without enteral feedings, the more severe the brush border atrophy and the longer the time that will be needed to restore absorptive capabilities of the intestine. Enterocytes are exclusively nourished by glutamine. Lack of glutamine supplementation reduces levels of immunoglobulin A and increases bacterial translocation. This photosensitive substance should be added to the patient's parenteral nutrition. Overall, the principle is to start enteral feedings as soon as the patient's clinical condition permits.

The current definition of intestinal failure is no longer anatomic, but rather, functional; intestinal failure is now defined as the presence of malabsorption after clinically significant small-bowel resection.³⁹

Although the minimal length of intestine necessary to maintain nutritional status is not fixed, newborns are estimated to require at least 10-20 cm of postduodenal small bowel to avoid short-bowel syndrome if the ileocecal valve and colon are preserved. When the ileocecal valve is resected, this requirement increases to 40 cm.⁴⁰ The loss of the ileum is the most difficult for which to compensate. The jejunum cannot perform some ileal functions, such as the absorption of bile acid and vitamin B-12. Therefore, a patient with ileal loss needs nutritional supplementation. The final length of the intestine is difficult to determine at the time of the operation because the length of the proximal dilated pouch may be overestimated, the neonatal bowel is undergoing growth, and the final length may be substantially larger than the length seen at surgery.

Surgical bowel-lengthening procedures and small-bowel transplantation are beyond the scope of this chapter, but they may prove beneficial in patients of short-bowel syndrome associated with multiple atresias. This is an exciting area, with new developments and opportunities to improve the survival and quality of life in this patient population.

COMPLICATIONS

Section 6 of 10  

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• Introduction
• RELEVANT ANATOMY
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

See Outcome and Prognosis.

OUTCOME AND PROGNOSIS

Section 7 of 10  

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• Introduction
• RELEVANT ANATOMY
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

Before the mid-20th century, the mortality rate associated with small-bowel atresias was prohibitive (>90%). The survival rate increased to 78% by the late 1950s. Survival rates improve with distal atresias, whereas mortality rates are high in instances of multiple atresia (57%); apple-peel deformity (54-71%); and atresias associated with meconium ileus (65%), meconium peritonitis (50%), or gastroschisis (66%).^{29, 1, 30, 15}

Overall survival rates (including preterm babies) have reached 90%, with a surgical mortality rate of less than 1%.^{29, 12, 30} Mortality is related to sepsis, associated anomalies, prematurity, malrotation, meconium peritonitis, and long-term TPN complications in patients with short-bowel syndrome.

The most common cause of death in infants with jejunoileal atresia is infection related to pneumonia, peritonitis, or sepsis.^{7, 1}

The most important surgical complications are anastomotic leaks and functional obstruction at the level of the anastomosis; one or the other occurs in as many as 15% of patients.^{7 10} In 84 patients with congenital jejunoileal or colonic atresia who were treated in New South Wales, Australia, the mortality rate was higher in infants who underwent stoma formation than in patients who received primary anastomosis.⁴¹

Short-bowel syndrome refers to a spectrum of malnutrition problems that result from inadequate bowel length, which may occur in patients born with multiple atresias or in those with the apple-peel deformity type. It is a cause of intestinal failure, together with other congenital diseases of enterocyte development, and severe motility disorders (total or subtotal aganglionosis or chronic intestinal pseudo-obstruction syndrome).⁴² Other common causes of short-bowel syndrome include necrotizing enterocolitis and midgut volvulus.⁴³

Today, the survival rate for patients with short-bowel syndrome is 80-94%. The presence or absence of the ileocecal valve does not appear to affect the mortality rate. However, it does notably affect the length of time that TPN is required and, therefore, affects the complications related to its use (eg, predisposition to infections, central line sepsis, TPN-related cholestasis).¹² Malabsorption and steatorrhea are most severe in patients with terminal ileal resection, particularly those in whom the ileocecal valve is excised. Vitamin B supplements are useful in this subset of patients.

Lack of sufficient residual bowel is responsible for considerable morbidity or a poor quality of life. In most instances, maximal intestinal adaptation occurs within 6-12 months but may take longer.¹⁵ The use of the Longitudinal Intestinal Lengthening and Tailoring (LILT) procedure, proposed by Bianchi and modified by Aigrain, can allow the child to be weaned from parenteral nutrition.⁴⁴

FUTURE AND CONTROVERSIES

Section 8 of 10  

• Authors and Editors
• Introduction
• RELEVANT ANATOMY
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

The use of growth factors to facilitate intestinal adaptation and advances in small-bowel transplantation may further improve the long-term outcome of children with small intestinal atresia and stenosis in the future.

MULTIMEDIA

Section 9 of 10  

• Authors and Editors
• Introduction
• RELEVANT ANATOMY
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

Media file 1:  Plain abdominal radiograph of a newborn reveals a dilated gastric bubble and a massively dilated duodenum and proximal jejunum with a gasless abdomen distal to the level of the obstruction; these findings are consistent with jejunal atresia.
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Media type:  Radiograph

Media file 2:  Upper-GI contrast study demonstrates a dilated stomach and duodenum, with an enlarged upper jejunum and a lack of passage of contrast agent to the distal small bowel; these findings are consistent with high jejunal atresia.
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Media type:  Radiograph

Media file 3:  Barium enema study reveals a microcolon in an infant with long-standing ileal atresia. Courtesy of Rebecca Stein-Wexler, MD.
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Media type:  Radiograph

Media file 4:  Intestinal stenosis. Dilated prestenotic bowel is in continuity with the distal intestine. No mesenteric gap is present. Bowel length is normal.
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Media type:  Illustration

Media file 5:  The transition area has a conical appearance due to windsock elongation of the membrane in atresia type I. No mesenteric gap is present. Bowel length is normal.
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Media file 6:  Intestinal atresia type II. The proximal dilated bowel is separated from the distal narrow one by a fibrous cord, in this case, without a mesenteric gap. Bowel length is normal.
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Media file 7:  Intestinal atresia type IIIa. Both blind ends are separated completely. A V-shaped mesenteric gap is present. Intestinal length is shortened.
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Media file 8:  Intestinal atresia type IIIB (apple-peel or Christmas-tree deformity). The proximal pouch is dilated. The collapsed distal intestine encircles the marginal artery helically. Intestinal length is substantially reduced.
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Media file 9:  Intestinal atresia type IV. Multiple atresias appear simultaneously as a string of sausages. The intestinal length is invariably and considerably shortened.
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Media file 10:  The surgical approach for patients with jejunoileal atresia is through an upper-right quadrant transverse incision that can extend across the midline if necessary.
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Media file 11:  Surgical image of a jejunal atresia type IIIa, with a proximal dilated pouch, completely separated from the distal narrow intestine, over a V-shaped gap mesenteric defect.
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Media type:  Photo

Media file 12:  Intestinal atresia type IIIa. A clamp is applied on the distal bowel, and sodium chloride solution is instilled through a purse-string suture to dilate the intestine and diminish the size discrepancy between the two loops to facilitate the anastomosis. The dotted line marks the area of the resection.
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Media file 13:  The proximal dilated pouch is transected in a 90° angle to maximize its vascularity, while the distal intestine is transected obliquely to diminish the size discrepancy between the segments.
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Media file 14:  Gastrostomy used for stomach decompression and to pass a transanastomotic tube for early postoperative enteral feeding.
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Media file 15:  Tapering jejunoplasty performed over a 26F tube to diminish the diameter of the proximal bowel and preserve bowel length.
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Media file 16:  Manually sewn tapering jejunoplasty.
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REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• RELEVANT ANATOMY
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

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Article Last Updated: Sep 26, 2007