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Duodenal and Intestinal Atresia and Stenosis
R2 Pornchai AchatsachatPediatric surgery unit, KCMH
Duodenal Atresia and Stenosis
Duodenal atresia and stenosis
o 1 per 5000–10,000 live births
o Boys > girls
o Associated anomalies 45–65%
o Trisomy 21 : almost 50%
o Cardiac malformations : 25–65%
o Malrotation : 30%
o Early postoperative survival rates > 90%
EtiologyMost well-known hypothesis Julius Tandler
Duodenal epithelial layer proliferates (green arrow)
Epithelial plug
(day42)
Recanalizes
(after 2 days)
Etiology
o 2 reliable genetic models (mouse embryos)
o Homozygous mutation of fibroblast growth receptor 2IIIb
o Homozygous mutation of ligand Fgf10
o Specific mutations (humans)
o 17q12 microdeletion, gene for hepatic nuclear factor β-1, critical for foregut development
o Homozygous mutation of RFX6, critical for normal pancreatic development
o Mutation in the FoxF1 gene, sonic hedgehog signaling pathway
Etiology
o Annular pancreas
o Failure of duodenal development rather than a true constricting external lesion
o Visible indication of an underlying atresia or stenosis
o The distal biliary tree is often abnormal and may open proximal or distal to the atresia or stenosis
o Other reported biliary abnormalities
o Biliary atresia
o Gallbladder agenesis
o Stenosis of the common bile duct
o Choledochal cyst
o Immune deficiency
Classification system
o Duodenal stenosis
o Incomplete obstruction (fenestrated web, diaphragm)
o Most stenoses involve 3rd and/or 4th part duodenum
o Duodenal atresia
o Type I : luminal diaphragm (mucosal + submucosal layers)
o Type II : connected by a fibrous cord
o Type III : obvious gap
Classification
o Duodenal atresia type I
o > 90% of all duodenal obstructions
o Contain a luminal diaphragm (mucosal + submucosal layers)
o Windsock = a diaphragm that has ballooned distally
Membrane Web Windsock
Classification
o Duodenal atresia type II
o Dilated proximal and collapsed distal segment connected by a fibrous cord
o Duodenal atresia type III
o Obvious gap separating the proximal and distal duodenal segments
Classification
o > 50% have associated anomalies
o 30% : trisomy 21
o 30% : isolated cardiac defects
o 25% : other GI anomalies
o 45% : premature
o 1/3 : growth retardation
Pathology
o Obstruction point
o Preampullary
o Postampullary : 85%
o In most cases, the GI tract can be decompressed proximally
o Polyhydramnios : 32-81%
o Growth retardation : common
Diagnosis
o Antenatal diagnosis
o Polyhydramnios
o Double bubble : 44%
o Most cases are detected between 7 and 8 months of gestation
Diagnosis
o Presentation
o Classic : bilious emesis within the first hours of life in stable neonate
o 15% preampullary : emesis is nonbilious
o Abdominal distention may or may not be present, scaphoid abdomen
o NG tube of > 20 mL of gastric contents in a newborn suggests intestinal obstruction (normal aspirate is <5 mL)
o Duodenal stenosis : feeding intolerance develops with emesis and gastric distention
Diagnosis
o Upright abdominal radiograph
o Double bubble sign with no distal bowel gas
o Decompressed stomach, 40–60 mL of instilled air into the stomach will reproduce the double bubble
o Upper GI contrast study to exclude malrotation and volvulus
Diagnosis
o Rarely, the biliary tree is air filled, and a variety of pancreatic and biliary anomalies have been demonstrated
DiagnosisDuodenal stenosis, a double bubble sign is often not present and the diagnosis is usually made with a contrast study
Management
o Resuscitation
o Gastric decompression
o Lab : Complete metabolic profile, CBC, coagulation studies
o Imaging : Abdominal and spinal US, Echocardiography
o Emergency operation : only in cases where malrotation with concurrent volvulus cannot be excluded
Management
o Preferred technique : either laparoscopic or open duodenoduodenostomy
o Proximal transverse to distal longitudinal (diamond-shaped) anastomosis
Management
o Malrotation should be evaluated : up to 30%
o Tapering duodenoplasty is generally not necessary
o Muscular continuity of the duodenal wall suggests a windsock deformity or diaphragm
Management
o Enteral feeding : waiting for the gastric output to become less bilious and the volume of gastric drainage to decrease
o The rate of concomitant jejunoileal atresia in patients with duodenal atresia was <1%
o Extensive inspection of the entire bowel does not appear necessary
o Early postoperative mortality : 3–5%
o Majority of deaths : associated congenital abnormalities
o Long-term survival approaches 90%
Management
o Long-term complications
o Delayed gastric emptying
o Severe gastroesophageal reflux
o Bleeding peptic ulcer
o Megaduodenum
o Duodenogastric reflux
o Gastritis
o Blind-loop syndrome
o Intestinal obstruction related to adhesions
Jejunoileal Atresia and Stenosis
Etiology
o 1 in 5000 live births
o Males = females
o 1/3 is premature
o Result of intrauterine ischemic insult to the midgut
o Presence of bile, lanugo hair, and squamous epithelial cells from swallowed amniotic fluid distal to an atresia suggests that the atresia occurs when the intestinal lumen was patent
Etiology
o The presence of associated extra-abdominal organ abnormalities in jejunoileal atresia is low (<10%)
o Usually not hereditary
o Autosomal recessive pattern of inheritance of multiple atresias>> poor survival
o No correlations have been found with parental or maternal disease
o The use of maternal vasoconstrictive medications, cigarette smoking in the first trimester has been shown to increase the risk of small bowel atresia
Pathology
o Multiple atresias : 30%
o Grosfeld classification system
o Stenosis : without disruption in the intestinal wall or a defect in the mesentery
o Type I : membrane or web (mucosa + submucosa)
o Type II : connected by a fibrous cord
o Type III(a) : V-shaped mesenteric defect
o Type III(b) : apple-peel, Christmas tree, or Maypole deformity
o Type IV : multiple-segment atresias or a combination
Pathology
o Stenosis
o localized narrowing of the intestinal lumen without disruption in the intestinal wall or a defect in the mesentery
o Often the muscularis is irregular and the submucosa is thickened
o Usually have a normal length of small intestine
Pathology
o Type I atresia
o Membrane or web formed by both mucosa and submucosa
o The bowel and its mesentery appear to be in continuity
o Bulging of the web into the distal intestine can create a windsock effect
o No foreshortening of the bowel
Pathology
o Type II atresia
o Proximal bowel loop connected by a fibrous cord to the collapsed distal bowel with an intact mesentery
o Increased intraluminal pressure in the dilated and hypertrophied proximal bowel may lead to focal proximal small bowel ischemia
o The total small bowel length is usually normal
Pathology
o Type III(a) atresia
o V-shapedmesenteric defect
o The dilated, blind-ending proximal bowel is often aperistaltic and frequently undergoes torsion or becomes overdistended, with subsequent necrosis and perforation
o The total length of the small bowel usually less than normal
Pathology
o Type III(b) atresia
o Apple-peel, Christmas tree, or Maypole deformity
o Absence of the superior mesenteric artery beyond the origin of the middle colic branch
o Agenesis of the dorsal mesentery
o A significant loss of intestinal length
o A large mesenteric defect
o Helical configuration around a single perfusing vessel arising from the ileocolic or right colic arcades
Pathology
o Type IV atresia
o Multiple-segment atresias or a combination
o Up to one-third of infants affected with jejunoileal atresia present with multiple atresias
o The majority are sporadic
o Likely a result of multiple vascular insults to the mesentery, intrauterine inflammatory processes, or a malformation of the GI tract
o CNS abnormalities 25%
Pathology
o Familial form of multiple intestinal atresia (FMIA)
o Involving the stomach, duodenum, and both the small and large bowel
o Associated with prematurity and shortened bowel length
o Autosomal Recessive
o Pathognomonic feature : sieve-like appearance of the intestine on histologic examination
o Multiple lumina are surrounded by epithelial cells and muscularis mucosa
Pathophysiology
o The blind-ended proximal bowel
o Dilated and hypertrophied with histologically normal villi
o Without effective peristaltic activity
o Deficiency of mucosal enzymes and muscular adenosine triphosphatase
o At the level of the atresia
o The ganglia of the enteric nervous system are atrophic with minimal acetylcholinesterase activity
o Defective peristalsis is commonly noticed
o Resection of the dilated bulbous proximal end for better function
Clinical manifestation
o Prenatal US : Dilated loops of bowel and polyhydramnios
o In neonates
o Bowel obstruction : bilious emesis and abdominal distention
o Meconium may appear normal, gray plugs of mucus passed via the rectum
o If the distal bowel in type III(b) atresia is ischemic, blood may be passed per rectum
o Intestinal stenosis
o Intermittent partial obstruction or malabsorption may improve without treatment
o Clinical investigations can initially be normal
o Usually develop failure to thrive and ultimately progress to complete intestinal obstruction and require exploration
Diagnosis
o Swallowed air reaches the proximal bowel by 1 hour and the distal small bowel by 3 hours
o Few gas-filled and fluid-filled loops of small bowel, but the remainder of the abdomen is gasless
o Cystic fibrosis
o Fewer air–fluid levels
o Typical groundglass appearance of inspissated meconium
o A limited-contrast study may be useful if intestinal stenosis is suspected
Diagnosis
o As haustral markings are rarely seen in neonates, distal ileal atresia may be difficult to differentiate from colonic atresia
o A contrast enema will reveal an unused appearance to the colon
o Occasionally, air and meconium can accumulate proximal to an atresia, mimicking the radiologic appearance of meconium ileus
o Total colonic aganglionosis can be difficult to differentiate from small bowel atresia
Diagnosis
o 10% present with meconium peritonitis
o The intestinal perforation usually occurs proximal to the obstruction, near the bulbous blind end
o The radiologic appearance of a meconium pseudocyst
o A large air–fluid level is related to the late intrauterine bowel perforation
o Intraluminal calcification of meconium or intramural calcification in the form of diffuse punctate or rounded aggregations
o Hereditary FMIA : string of pearls (pathognomonic for this condition)
Differential diagnosis
o Colonic atresia
o Midgut volvulus
o Meconium ileus
o Duplication cysts
o Internal hernias
o Ileus due to sepsis
o Birth trauma
o Maternal medications
o Prematurity
o Hypothyroidism
Differential diagnosis
o Special investigations
o Upper GI contrast study
o Contrast enema
o Rectal biopsy
o ΔF508 gene deletion assay or sweat test to exclude associated cystic fibrosis
Management
o Delay in diagnosis can lead to
o Impairment of intestinal viability (50%)
o Frank necrosis and perforation (10–20%)
o Fluid and electrolyte abnormalities
o Sepsis
o Preoperative management
o Gastric decompression
o Fluid resuscitation
o Antibiotics should be initiated if there is suspicion for perforation or infection
Surgical considerations
o Prognosis is dependent
o Length of remaining bowel
o Presence/absence of the ileocecal valve
o Neonates with < 25 cm of bowel will likely require parenteral nutrition and intestinal lengthening procedures
o Most common technique : Resection of the dilated and hypertrophied proximal bowel with primary end-to-end anastomosis with or without tapering of the proximal bowel
o Current survival rate is >90%
Operative considerations
o Laparoscopic approach
o Subsequent resection and anastomosis performed in an extracorporeal fashion
o Difficult to identify the atresia
o Explore the abdomen
o Circumumbilical incision
o Transverse abdominal incision
Operative considerations
o Site and type of obstruction should be noted
o Length of bowel should be assessed
o The most distal limb of the atretic bowel can then be cannulated with a red rubber catheter and irrigated with warm saline to evaluate for distal obstruction
o Continuity of the colon can be established preoperatively by a contrast enema or with a prepositioned transrectal catheter placed prior to prepping
o Failure to adequately evaluate for distal obstruction or stenosis can lead to postoperative complications, including an anastomotic leak
o If present, malrotation should be corrected with a Ladd procedure
o Length of functional bowel should be carefully measured along the antimesenteric border
Operative considerations
o If the length of functional bowel is adequate, the bulbous hypertrophied proximal bowel should be resected to approximately normal caliber bowel
o The goal is to restore bowel continuity while maintaining both intestinal function and length
o Once the anastomosis is completed, the suture line is tested for leaks
o The mesenteric defect is repaired with careful attention to avoid rotation or kinking of the anastomosis, or injury to the blood supply
o A temporary enterostomy should be performed if there is a question of bowel viability
Prognostic factors
o Normal small bowel length
o Term neonates : 250 cm
o Preterm infants : 160–240 cm
o If proximal resection will lead to significant, or unacceptable, bowel loss, tapering or plication of the dilated bowel is a useful technique
o The tapering can be safely performed up to 35 cm
o A primary anastomosis may be contraindicated in
o Peritonitis
o Volvulus with vascular compromise
o Meconium ileus
o Type III(b) atresia
Prognostics factor
o 13% of gastroschisis had an associated atresia
o The most common location for the atresia was jejunoileal
o Most were type III(a)
o In nearly all instances, the atresia should be left undisturbed at the initial operation
o After fascial closure is accomplished, management should include gastric decompression and TPN support with subsequent atresia repair 4–6 weeks later
Prognostics factor
o Type III(b) atresia
o Restricting bands along the free edge of the distal coiled and narrow mesentery should be divided to optimize the blood supply
o The bowel should be returned to the abdomen with careful inspection of the mesentery to prevent torsing the single marginal artery and vein
o Bowel-length conservation methods, such as multiple anastomoses for multiple atresias, may result in increased morbidity
Postoperative care
o Parental nutrition, if utilized, should begin as soon as possible and should continue until the infant is tolerating full enteral feeds
o Enteral feedings can be initiated when the gastric aspirate is clear, output is minimal, and the infant is stooling
o Start the enteral feeding through a feeding tube at a rate of 20 mL/kg/day of breast milk or formula in a continuous fashion
o The feeds are increased by 20–30 mL/kg/day
o Oral intake is initiated when the baby is alert, able to suck, and tolerating at least 8 mL of tube feeds per hour
Postoperative care
o Transient GI dysfunction is frequently observed
o Lactose intolerance, malabsorption, and diarrhea may be significant in infants who have undergone repair of type III(b) atresia, or in those with short bowel syndrome after surgery
o Regular monitoring for clinical signs of intestinal overload or intolerance is required
o Loperamide hydrochloride decreases intestinal peristaltic activity, and cholestyramine is effective in binding bile salts
o Cholestyramine should not be given unless water-loss stools are evident
o Vitamin B12 and folic acid should be given regularly to the patient without a terminal ileum to prevent megaloblastic anemia
Postoperative care
o A functional outcome ultimately depends on the following factors
o (1) the location of the atresia (the ileum adapts to a greater degree than the jejunum)
o (2) the maturity of the intestine (the small intestine in a premature infant still has time for maturation and growth)
o (3) the length of the small intestine, which can be difficult to determine accurately after birth
o The ileocecal valve is critically important, as it allows for more rapid intestinal adaptation when the residual small bowel length is short
Colonic Atresia
Introduction
o 2–15% of all GI atresias
o 1 in 20,000 live births
o Most commonly reported as an isolated anomaly
o 1/3 of babies have associated congenital lesions
o Etiology : vascular insult to the colon
Classification
o Type I : mucosal atresia, more commonly distal to the splenic flexure
o Type II : fibrous cord, more commonly distal to the splenic flexure
o Type III : V-shapedmesenteric gap, most commonly occurring lesions
Clinical presentations
o Abdominal distention
o Bilious emesis
o Failure to pass meconium
o On plain radiographs
o Air–fluid levels
o Dilated intestinal loops of large bowel
o Ground-glass appearance of meconium mixed with air
o Mimics pneumoperitoneum
Diagnosis
o Contrast enema showing a small diameter distal colon that comes to an abrupt halt at the level of the obstruction
Management
o Urgent operative management : high risk for perforation
o Exclude other intestinal atresias and stenoses at the time of operation
o Frozen section analysis of rectal biopsies during the initial surgery as unrecognized HD can lead to an anastomotic leak or functional obstruction
o Staged approach : colostomy with mucous fistula
o Resection of the bulbous proximal colon as well as a portion of the distal microcolon
Prognosis
o In the absence of other serious comorbidities
o Diagnosed early : mortality < 10%
o Delay in diagnosis beyond 72 hours : mortality > 60%
o >> Closed loop obstruction between an intact ileocecal valve and the atresia
o >> Massive colonic distention and perforation
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