Duodenal and Intestinal Atresia and Stenosis Flashcards
The most common cause of duodenal obstruction at birth is:
A. Malrotation
B. Duodenal atresia
C. Annular pancreas
D. Choledochal cyst
E. Midgut volvulus
ANSWER: B
COMMENTS: Vomiting within the first 24 h of life in the absence of abdominal distention suggests duodenal atresia in a neonate.
Malrotation with midgut volvulus is the most common and the most devastating cause of a duodenal obstruction beyond the neonatal period.
In malrotation, the duodenal obstruction may be caused by extrinsic compression by the peritoneal Ladd’s bands that extend from the abdominal wall to the anomalously located cecum in the right upper quadrant.
Alternatively, the catastrophic complication of malrotation is midgut volvulus and intestinal infarction from the torsion of the superior mesenteric vessels about the narrow mesenteric pedicle by which the midgut is suspended.
An annular pancreas may cause duodenal obstruction as a result of duodenal stenosis. Choledochal cysts are rare and manifest as jaundice and an abdominal mass.
A newborn infant presents with a radiograph showing a dilated stomach and proximal duodenum.
What is the appropriate operative intervention?
A. Duodenojejunostomy
B. Duodenoduodenostomy
C. Gastrojejunostomy
D. Orogastric tube decompression alone
E. Ladd’s procedure
ANSWER:
B
COMMENTS: The radiograph is demonstrating a classic “double bubble” sign that is seen with duodenal atresia.
This diagnosis can be made in utero with polyhydramnios as well as a double bubble seen on ultrasound.
The double bubble appearance results from air swallowing that does not progress through the duodenal atresia.
The stomach and proximal duodenum dilate, and there is no air in the bowel distal to the atresia.
There are three types of duodenal atresia.
Type 1, by far the most common, is a web or septum obstructing the duodenal lumen.
It is thought to be the result of a failure to recanalize the lumen during development. This is most commonly located in the second portion of the duodenum.
Type 2 is a solid cord between the two lumens of the affected portion of the duodenum.
Type 3 is two blind-ending duodenal loops, proximal and distal, without a connection between them.
Duodenal atresia is associated with a congenital heart disease, trisomy 21, and annular pancreas.
Prior to a surgical correction, it is important to evaluate the infant with an echocardiogram to look for cardiac abnormalities.
The child may be managed with orogastric tube decompression and intravenous fluids until optimization for surgery.
At surgery, a right upper quadrant incision is made. The entire length of the duodenum is evaluated.
Most of the time, a duodenoduodenostomy is created to join the two segments of bowel.
If an annular pancreas or preduodenal portal vein is identified, the anastomosis should be made anterior to this.
Although it is possible that a Ladd’s band and an intestinal malrotation could cause duodenal obstruction, it is a much less common reason for a double bubble sign than duodenal atresia.
Discuss intestinal atresia and stenosis.
Congenital intestinal obstruction occurs in approximately 1 in 2000 live births and is one of the most common causes for admission to a neonatal care unit.
Morphologically they are divided into either atresia and stenosis depending the continuity of the intestine.
Furthermore, they are divided by the region of the gastrointestinal tract involved: duodenal, jejunoileal and colonic.
Prenatally they present as polyhydramnios and dilation of the intestine on ultrasound.
Neonatally infants present with obstructive symptoms.
Usually a radiograph is enough to make the diagnosis of any of these conditions, depending the point of obstruction there might be a “double-bubble” sign or more diffuse intestinal dilation with or without pneumoperitoneum.
For more distal obstruction a contrast enema might be needed.
Treatment is surgical with a thorough exploration and repair through a single anastomosis or resection with or without anastomosis depending the portion of the gastrointestinal tract involved, other abnormalities and if perforation had occurred.
What is the incidence of congenital intestinal obstruction?
The incidence of congenital intestinal obstruction is about 1 in 200 live births.
The incidence of both duodenal and jejunal atresia (the most common) is 1 per 5,000 live births, and the incidence of colonic atresia is 1 in 20,000 live births.
What is the cause of congenital duodenal obstruction?
Congenital duodenal obstruction occurs secondary to intrinsic or extrinsic lesions.
The most common intrinsic lesion is duodenal atresia.
As of today, the mechanism is unclear, however some theories aim towards defects in the epithelial plugging of the duodenum in early development related with fibroblast growth receptor.
Other intrinsic causes include duodenal webs and diaphragm.
Extrinsic causes include annular pancreas, or abnormalities in the biliary tree such as biliary atresia, gall- bladder agenesis, common bile duct stenosis or choledochal cysts.
How is congenital duodenal obstruction classified?
Duodenal obstructions are classified as three types of stenosis or atresia.
Type I is either a membrane or a web leading to the obstruction. In type I the duodenum remains in continuity.
Type II duodenal atresia is characterized by complete obliteration of the duodenal lumen, replaced by a fibrous cord.
Type III is the result of compete separation of the proximal and distal duodenal segments.
How often are other abnormalities associated with duodenal atresia?
Associated abnormalities have been encountered in about 45–65% of the cases.
Trisomy 21 and cardiac defects have been encountered in up to 30% of the cases followed by other gastrointestinal abnormalities (such as malrotation) in 25% of the cases.
Other abnormalities are renal, esophageal atresia, imperforate anus or skeletal abnormalities.
Where is the obstruction most commonly located in congenital duodenal obstruction?
It is estimated that 85% of the obstructions occur distal to the ampulla.
How is duodenal obstruction diagnosed?
Polyhydramnios should raise a concern as 32–81% of congenital duodenal obstruction presents with this finding.
Sonographic evaluation can identify the two fluid filled strictures (double-bubble sign) in about 44% of the cases, this is mostly accomplished by week 28–32 due to lower gastric pressure in early development phases.
Neonatally, a plain radiograph is usually enough.
What is the double bubble sign and how can it be reproduced?
The double bubble sign is commonly related to duodenal obstruction.
The proximal bubble represents the air-fluid stomach whereas the second bubble represents the dilated distal duodenum.
In cases of duodenal atresia is often encountered with a concomitant gasless distal abdomen.
However, presence of air does not exclude the diagnosis of congenital duodenal obstruction as there might be abnormalities in the biliary tree that could let the air bypass the obstruction.
This sign can often be reproduced by instilling 40–60 ml of air into the stomach.
Is important to note that this sign is often not present in stenosis as the obstruction is not complete.
What is the treatment of duodenal atresia?
The treatment that is now preferred is an open or laparoscopic proximal transverse and distal longitudinal (diamond-shaped) duodenoduodenostomy.
If a web is the cause a vertical duodenotomy with a web excision and transverse closure is enough.
Should the duodenoduodenostomy be performed laparoscopic or open?
Since its first description by Rothenberg in 2002, multiple studies have compared laparoscopic vs open duodenal duodenoduodenostomy.
Literature shows that the laparoscopic repair is safe, allows better visibility and offers the advantage of early feeding and shorter hospitalization time.
During a duodenal atresia repair should the intestine be evaluated for malrotation or other atresia?
Abdomen should be inspected for malrotation is it has been related to up to 30% of the cases of duodenal atresia.
Historically it was recommended to evaluate the intestine for other atresia, however recent literature shows that the rate of other intestinal atresia is less than 1% for which extensive inspection does not appear necessary.
What are the issues related to long side-to-side duodenoduodenostomies and duodenojejunostomies?
The use of a long side to side duodenostomy has been related to a high incidence of anastomotic dysfunction and prolonged obstruction (12%).
Duodenojejunostomies have been related to an increased risk of blind loop syndrome.
What is the cause of jejunoileal atresia?
Several hypotheses and clinical data point towards a vascular disruption that results in mesenteric disruption and interference with the segmental blood supply of the small bowel resulting in atresia and stenosis.
It usually occurs latter in the small bowel development as an intrauterine insult.
However there has been reports of hereditary forms that occur way early in development that are related with multiple atresia and poor survival.
Is jejunoileal atresia related to other abnormalities?
As the mechanism is different from other abnormalities and is often secondary to a vascular insult, jejunoileal atresia is related to other abnormalities in less than 1% of the cases.
There have been reports relating it with patients with Hirschsprung’s Disease, cystic fibrosis (10%), malrotation, Down syndrome, congenital heart disease and other atresias (6%).
How is jejunoileal atresia classified?
The Louw’s classification system (and then modified by Grosfield) is shown below and divides them in four groups.
This classification depends on the most proximal segment and has both diagnostic and prognostic value.
Stenosis
Stenosis is defined as a localized narrowing of the intestinal lumen without disruption in the intestinal wall or a defect in the mesentery. At the stenotic site, a short, narrow, somewhat rigid segment of intestine with a small lumen is found. Often the muscularis is irregular and the submucosa is thickened. Stenosis may also take the form of a type I atresia with a fenestrated web. Patients with jejunoileal stenosis usually have a normal length of small intestine.
Type I Atresia
In type I jejunoileal atresia, the intestinal obstruction occurs secondary to a membrane or web formed by both mucosa and submucosa, while the muscularis and serosa remain intact. On gross inspection, the bowel and its mesentery appear to be in continuity. However, the proximal bowel is dilated while the distal bowel is collapsed. With the increased intraluminal pressure in the proximal bowel, bulging of the web into the distal intestine can create a windsock effect. As with stenosis, there is no foreshortening of the bowel in type I atresias.
Type II Atresia
The clinical findings of a type II atresia are a dilated, blindending proximal bowel loop connected by a fibrous cord to the collapsed distal bowel with an intact mesentery. Increased intraluminal pressure in the dilated and hypertrophied proximal bowel may lead to focal proximal small bowel ischemia. The distal collapsed bowel commences as a blind end, which sometimes assumes a bulbous appearance owing to the remains of an intussusception. Again, the total small bowel length is usually normal.
Type III(a) Atresia
In type III(a) atresia, the proximal bowel ends blindly, with no fibrous connecting cord to the distal intestine. A V-shaped mesenteric defect of varying size is present between the two ends of intestine. The dilated, blind-ending proximal bowel is often aperistaltic and frequently undergoes torsion or becomes overdistended, with subsequent necrosis and perforation occurring as a secondary event. In this scenario, the total length of the small bowel is variable (but usually less than normal), owing to intrauterine resorption of the affected bowel.
Type III(b) Atresia
Type III(b) atresia (apple-peel, Christmas tree, or Maypole deformity) consists of a proximal jejunal atresia, absence of the superior mesenteric artery beyond the origin of the middle colic branch, agenesis of the dorsal mesentery, a significant loss of intestinal length, and a large mesenteric defect. The decompressed distal small bowel lies free in the abdomen and assumes a helical configuration around a single perfusing vessel arising from the ileocolic or right colic arcades. Occasionally, additional type I or type II atresias are found distal to the initial atresia. It has also been shown that type III(b) atresias are significantly more likely to present with volvulus and are at risk for impaired vascularity of the distal bowel. This type of atresia has been found in families with a pattern suggestive of an autosomal recessive mode of inheritance. It also has been encountered in siblings with identical lesions and in twins.
The occurrence of intestinal atresia in other siblings, the association of multiple atresias (15%), and the discordance in a set of apparently monozygotic twins may point to more complex genetic transmission for type III(b) atresias in around 20%. Infants with this anomaly are often premature, and up to 50% may have malrotation. Accordingly, there is increased morbidity (63%) and mortality (54%) in this population. Type III(b) atresias are most likely the result of a proximal superior mesenteric arterial occlusion with extensive infarction of the proximal segment of the midgut. Also, it can develop from a midgut volvulus. Primary failure of development of the distal superior mesenteric artery has also been suggested as an etiologic factor. However, this is unlikely because meconium is usually found in the bowel distal to the atresia. This finding indicates that the atresia develops after bile secretion begins, which occurs around week 12 of intrauterine life. The superior mesenteric artery develops much earlier than 12 weeks.
Type IV Atresia
Multiple-segment atresias or a combination of types I to III are classified as type IV. Up to one-third of infants affected with jejunoileal atresia present with multiple atresias. The majority of cases of multiple-segment atresias are sporadic with no other family history of intestinal abnormalities. They are likely a result of multiple vascular insults to the mesentery, intrauterine inflammatory processes, or a malformation of the GI tract occurring during embryonic development. Embolic material from a nonviable fetus to a living monochorionic twin through placental vascular connections could also account for single or multiple intestinal atresias. Associated defects, particularly abnormalities of the central nervous system, have been noted in approximately 25% of nonfamilial multiple intestinal atresia patients. Multiple atresias have also been seen in association with severe immunodeficiency associated with a rare mutation in the tetratricopeptide repeat domain–7A (TTC7A) gene, which aids in the development of the thymus and intestinal epithelium.
A familial form of multiple intestinal atresia (FMIA) involving the stomach, duodenum, and both the small and large bowel has been described. It is associated with prematurity and shortened bowel length. To date, it has been uniformly fatal. It is associated with type I and II atresias, with type II predominating. An autosomal recessive mode of transmission has been suggested for this familial condition because it is unlikely that an isolated prenatal vascular accident is responsible for such extensive involvement of the GI tract. In addition, infants affected with this familial form are found to have long segments of completely occluded small or large intestine without a recognizable lumen. Another pathognomonic feature seen in FMIA is the sieve-like appearance of the intestine on histologic examination where multiple lumina are surrounded by epithelial cells and muscularis mucosa.
H&A
How is the clinical presentation of jejunoileal atresia?
Prenatal ultrasound might show dilated loops of bowel and polyhydramnios, however the majority of this atresias are not diagnosed prenatally.
In the neonatal period, symptoms are of bowel obstruction (bilious emesis and abdominal distension).
Meconium can appear to be normal but often there can be gray plugs or blood (in type II(b)).
What are the radiological findings of jejunoileal atresia?
Usually a plan radiograph with swallowed air is enough to make diagnosis.
In cases of proximal atresia there are some gas-filled and fluid filled loops with the remainder of the abdomen being gasless.
Distal atresias are harder to differentiate from colonic atresias due to absence of haustral markings so contrast enema can be used to aid the diagnoses.
About 10% of the patients can present with meconium peritonitis with radiologic findings of a large pseudocyst with a large-air- fluid level.
What are some important operative considerations when performing an abdominal exploration for a neonate with suspected jejunoileal atresia?
– A usual transverse abdominal incision can be used, however a circumbilical incision has been found to be as effective with best cosmetic results. We usually perform a vertical umbilical incision due to the ease of small bowel exteriorization.
– Careful examination must be performed to avoid missing segments or other atresias. Intraoperative contrast enema or cannulation with a red rubber catheter can be used.
– Resection of the dilated and hypertrophied proximal segments with primary end-to-end anastomosis is the most common technique.
– The proximal bowel can also be tapered or imbricated to maintain mucosal surface.
– Mesenteric repair must be done carefully to avoid damage to the blood supply due to rotating or kinking movements.
– In cases of concomitant gastroschisis we recommend fascial closure, gastric decompression, total parenteral nutrition (TPN) and repair of the atresia 4–6 weeks later.
– Special care has to be taken for type III(b) atresia, restricting bands should be released and mesentery should be placed in a way to prevent torsing of the single marginal artery that irrigates the segment.
– No intestinal lengthening procedures should be attempted in the first intervention.
– Remaining bowel length should be carefully measured as it is a vital prognostic factor.
What are the most important prognostic factors after management of a jejunoileal atresia?
Bowel length and presence/absence of the ileocecal valve are the most important factors.
Usually neonates with <25 cm of bowel will require long-term TPN and intestinal lengthening procedures, whereas <100 cm will require at least short- term TPN.
Other factors include the location of the atresia (ileum adapts better) and the maturity of the intestine (premature infant might have more time for growth).
What are the types of colonic atresia?
– Type I mucosal atresia with intact bowel wall and mesentery
– Type II Atretic ends are separated by a fibrous cord
– Type III atretic ends are separated by a V-shaped mesentery.
What is the cause of colonic atresia?
Studies nowadays point towards a vascular insult to the colon as in jejunoileal atresia.
What are the abnormalities related to colonic atresia?
The rate of other abnormalities is low.
Colonic atresia can be found in 2.5% of the children with gastroschisis.
There have been some reports in patients with Hirschsprung’s Disease (HD), complex urological abnormalities, multiple jejunoileal atresias and skeletal abnormalities.
How is colonic atresia diagnosed?
Initial evaluation with abdominal X-ray might show large and dilated intestinal loops difficult to differentiate from other atresias or pneumoperitoneum.
Diagnosis is made by a contrast enema showing an abrupt halt where the obstruction is.
How is colonic atresia treated?
Operative exploration is warranted as this type of atresia has higher risk of perforation.
Is important to exclude other atresias and stenoses.
Is recommended to perform a frozen biopsy for HD as it may lead to anastomotic leak or obstruction.
For right sided colonic atresia resection and primary anastomosis is possible: for left sided a staged approach with a colostomy with a mucous fistula with resection of both proximal and distal edges is recommended.
Closure is then performed months later.
One-day-old baby with bilious vomiting; examination shows Down syndrome and epigastric fullness. X-rays show double bubble sign. The most likely diagnosis is:
A. Oesophageal atresia. B. Pyloric stenosis. C. Duodenal atresia. D. Jejunal atresia. E. Ileal atresia.
C. Duodenal atresia.
The conditions most likely associated with duodenal atresia are Down syndrome, malrotation, congenital heart disease, annular pancreas and oesophageal atresia.
Syed/MCQ
Type II duodenal atresia is:
A. Simple intraluminal membrane.
B. Intraluminal membrane with wind-sock type.
C. Intraluminal membrane with perforation.
D. Intraluminal membrane with annular pancreas.
E. Blind ends of duodenum connected with a fibrous cord.
E. Blind ends of duodenum connected with a fibrous cord.
Syed/MCQ
In duodenal atresia, which of the following is not true?
A. Diamond duodenostomy is a good option.
B. Kocher’s manoeuvre is needed during the operation.
C. Either one-layer or two-layer anastomosis technique can be used.
D. If the trans-anastomotic tube is placed, the feed is started on the fourth day.
E. The outcome depends on associated condition, anastomotic leakage, intra-abdominal sepsis and wound complication.
D. If the trans-anastomotic tube is placed, immediate enteral feed can be started.
Syed/MCQ
In type I duodenal atresia, the preferred method of surgery is:
A. Complete excision of membrane.
B. Partial excision of membrane, leaving a small part at the medial side.
C. Partial excision of membrane, leaving a small part at the lateral side.
D. Duodenostomy.
E. Duodenojejunostomy.
B. Leaving a small part on medial side is intact because of chance of damage of ampulla of Vater.
D and E are preferred method for type II and type III atresia.
Syed/MCQ
Regarding association of duodenal atresia, which of the following is true?
A. Down syndrome
B. Congenital heart disease
C. Malrotation 30 percent
D. Annular pancreas 30 percent
E. All of the above.
E. All of the above are true.
Syed/MCQ
Regarding duodenal atresia, which of the following statements is true?
A. Type III atresia is commonest.
B. Fifty percent obstruction is below the ampulla of Vater.
C. Windsock is variant of type I atresia.
D. Survival rate is 60 percent.
E. Almost all reported deaths are from sepsis.
C. Windsock is a variant of type I atresia.
Type I atresia is the commonest. Obstruction below the ampulla is seen in 85 percent of cases. Survival rate is 90-95 percent. Most deaths are due to complex congenital heart disease.
Syed/MCQ
The apple-peel variety of jejunal atresia is:
A. Type I atresia.
B. Type II atresia.
C. Type III A atresia.
D. Type III B atresia.
E. Type IV atresia.
D. Type III B atresia is called apple peel variety of jejunal atresia.
Syed/MCQ
Principles for tapering enteroplasty?
If proximal resection will lead to significant, or unacceptable, bowel loss, tapering or plication of the dilated bowel is a useful technique.
Tapering enteroplasty as far proximal as the second portion of the duodenum can be accomplished by resecting an antimesenteric strip of the dilated proximal bowel.
During tapering duodenojejunoplasty, particularly with type III atresias, the duodenum is de-rotated, thus allowing a direct caudal descent from the stomach, which decreases the risk for obstruction. Additionally, the mesentery should be maximally opened, while meticulously protecting the small bowel vascular supply. During this process, the cecum can be mobilized to the left, which results in a broader mesentery and also allows the anastomosis to lie in manner that will help avoid kinking.
The tapering can be safely performed up to 35 cm.
The tapered bowel may then be anastomosed to the distal bowel or exteriorized as a stoma.
How are duodenal obstructions classified?
Anatomically, duodenal obstructions are classified as either atresias or stenoses.
An incomplete obstruction, due to a fenestrated web or diaphragm, is considered a stenosis. Most stenoses involve the third and/or fourth part of the duodenum.
Atresias, or complete obstruction, are further classified into three morphologic types.
Type I
Type I atresias account for >90% of all duodenal obstructions and contain a luminal diaphragm that includes mucosal and submucosal layers.
A diaphragm that has ballooned distally (windsock) is a type I atresia.
It is important to understand that the anatomy of the windsock may lead to a portion of the dilated duodenum actually being distal to the actual obstruction.
Type II
Type II atresias are characterized by a dilated proximal and collapsed distal segment connected by a fibrous cord.
Type III
Type III atresias have an obvious gap separating the proximal and distal duodenal segments.
More than 50% of affected patients with duodenal atresia have associated congenital anomalies.
Approximately 30% are associated with trisomy 21, 30% with isolated cardiac defects, and 25% with other gastrointestinal (GI) anomalies.
Approximately 45% of babies are premature, and about one-third exhibit growth retardation.
H&A
How is duodenal atresia diagnosed antenatally and postnatally?
There are multiple benefits to the antenatal diagnosis of duodenal obstruction, including parental counseling.
The diagnosis can often be suggested by prenatal ultrasound (US).
Sonographic evaluation in fetuses of mothers with a history of polyhydramnios can detect two fluid-filled structures consistent with a double bubble in up to 44% of cases.
Despite duodenal obstruction usually occurring by week 12, the reason for failure of early prenatal detection is not entirely clear.
Most cases of duodenal atresia are detected between 7 and 8 months of gestation.
It is currently believed that immature gastric emptying in utero may contribute to low gastric pressures, failing to dilate the proximal duodenum until later in gestation.
While both circular and longitudinal muscle layers are present in the stomach by week 8 of gestation, pressure amplitudes at 25 weeks are only 60% of term gastric pressures.
The presentation of the neonate with duodenal obstruction varies depending on whether the obstruction is complete or incomplete, and the location of the ampulla of Vater in relation to the obstruction.
The classic presentation is that of bilious emesis within the first hours of life in an otherwise stable neonate.
In about 15% of cases, however, the atresia is preampullary and the emesis is nonbilious.
Abdominal distention may or may not be present. In neonates with duodenal atresia, the abdomen is scaphoid.
Aspiration via a nasogastric (NG) tube of >20 mL of gastric contents in a newborn suggests intestinal obstruction as the normal aspirate is <5 mL.
For patients with stenosis, the diagnosis is often delayed until the neonate has started on enteral feeds and feeding intolerance develops with emesis and gastric distention.
In antenatally suspected cases of duodenal obstruction, as well as in neonates with a clinical presentation consistent with a proximal bowel obstruction, an upright abdominal radiograph is usually sufficient to confirm the diagnosis of duodenal atresia.
The diagnostic radiographic presentation of duodenal atresia is that of a double bubble sign with no distal bowel gas.
The proximal left-sided bubble represents the air- and fluid-filled stomach while the dilated proximal duodenum represents the second bubble to the baby’s right of midline.
In almost all cases of duodenal atresia, the distal bowel is gasless. However, the presence of distal gas does not necessarily exclude the diagnosis of atresia as there is a report of a bifed common bile duct with insertion of one of the ducts proximal and the other distal to the atretic segment, which allowed the air to bypass the atresia.
In neonates whose stomach has been decompressed by either NG aspiration or vomiting, 40–60 mL of instilled air into the stomach will reproduce the double bubble.
Rarely, the biliary tree is air filled, and a variety of pancreatic and biliary anomalies have been demonstrated.
At our institution, neonates who present with bilious emesis and a decompressed stomach on plain abdominal films receive a limited upper GI contrast study to exclude malrotation and volvulus.
With duodenal stenosis, a double bubble sign is often not present and the diagnosis is usually made with a contrast study.
H&A
How is duodenal atresia managed?
After the diagnosis is made, appropriate resuscitation is required with correction of fluid balance and electrolyte abnormalities, in addition to gastric decompression.
At our institution, all neonates diagnosed with duodenal obstruction receive a complete metabolic profile, complete blood count, coagulation studies, an abdominal and spinal US, and two-dimensional echocardiography prior to any operation.
An emergency operation is performed only in cases where malrotation with concurrent volvulus cannot be excluded.
Prior to the mid-1970s, duodenojejunostomy was the preferred technique for correcting duodenal atresia or stenosis. Since then, the various techniques utilized have included side-to-side duodenoduodenostomy, diamond-shaped duodenoduodenostomy, partial web resection with Heineke–Mikulicz-type duodenoplasty, and tapering duodenoplasty.
The long side-to-side duodenoduodenostomy, although effective, is associated with a high incidence of anastomotic dysfunction and prolonged obstruction.
Blind-loop syndrome appears to be more common in patients treated with duodenojejunostomy.
Gastrojejunostomy should not be performed as it is associated with a high incidence of marginal ulceration and bleeding.
Currently, the preferred technique is either laparoscopic or open duodenoduodenostomy.
Originally, a side-to-side anastomosis was performed.
A proximal transverse to distal longitudinal (diamond-shaped) anastomosis is now preferred.
For the open approach, either a right upper quadrant supraumbilical transverse incision or an umbilical crease incision is utilized.
After mobilizing the ascending and transverse colon to the left, the duodenal obstruction is readily exposed.
Malrotation should be evaluated at this point as it can occur in association with congenital duodenal obstruction in up to 30% of patients.
A sufficient length of duodenum distal to the atresia is mobilized to allow for a tension-free anastomosis.
A transverse duodenotomy is made in the anterior wall of the distal portion of the dilated proximal duodenum, and a similar length duodenotomy is made in a vertical orientation on the antimesenteric border of the distal duodenum.
The anastomosis is then fashioned by approximating the end of each incision to the appropriate midportion of the other incision.
Tapering duodenoplasty is generally not necessary as the proximal duodenal dilation usually resolves after relief of the obstruction.
Muscular continuity of the duodenal wall suggests a windsock deformity or diaphragm.
This finding should precipitate extra vigilance in the operative correction because the dilated and collapsed bowel are both distal to the windsock, and have been anastomosed in error.
The laparoscopic approach was first described by Rothenberg in 2002. The standard laparoscopic approach begins with the patient supine, and the abdomen is insufflated through the umbilicus.
Two other instruments are inserted, one in the baby’s right lower quadrant and one in the right mid-epigastric region, respectively.
A liver retractor can be placed in the right or left upper quadrant if necessary.
Alternatively, the liver can be elevated by placing a transabdominal wall suture around the falciform ligament and tying it outside the abdomen.
The duodenum is mobilized, and the location of obstruction is identified. Using the same principles that have been described for the open approach, a standard diamond-shaped anastomosis is created.
Several studies have compared open and laparoscopic repair of duodenal atresia and have shown that the laparoscopic repair is as safe as the open and highlighted the advantages of early feeding.
The historical approach to enteral feeding following duodenal atresia repair involved a period of waiting for the gastric output to become less bilious and the volume of gastric drainage to decrease, indicating return of intestinal function.
One study showed that the time spent waiting for the gastric output to decrease is likely not necessary as all of the patients undergoing the laparoscopic duodenoplasty had initiation of feeds without adverse events after an upper GI contrast study on day 5 revealed no leak.
When compared with infants undergoing an open operation with the historical postoperative management mentioned previously, there was a marked reduction in hospitalization for the laparoscopically corrected infants, primarily due to the early feeding.
Historically, during repair of duodenal atresia, it has been emphasized that inspecting the entire small bowel to identify a second atresia is important.
Given that duodenal atresia and jejunoileal atresia do not share common embryologic etiologies, a multi-institutional review of duodenal atresia patients was undertaken to quantify the incidence of jejunoileal atresia in this population.
In this largest series to date, the rate of concomitant jejunoileal atresia in patients with duodenal atresia was <1%.
With the low incidence of a concomitant distal atresia, extensive inspection of the entire bowel does not appear necessary.
Early postoperative mortality for duodenal atresia repair has been reported to be as low as 3–5%, with the majority of deaths occurring secondary to complications related to associated congenital abnormalities.
Long-term survival approaches 90%.
Long-term complications have been noted following repair and include delayed gastric emptying, severe gastroesophageal reflux, bleeding peptic ulcer, megaduodenum, duodenogastric reflux, gastritis, blind-loop syndrome, and intestinal obstruction related to adhesions.
H&A
What is the etiology of jejunoileal atresia and stenosis?
Jejunoileal atresia occurs in approximately 1 in 5000 live births.
It occurs equally in males and females, and about one in three infants is premature.
Although the majority of cases are thought to occur sporadically, familial cases of intestinal atresia have been described.
It is generally accepted that jejunoileal atresia occurs as a result of an intrauterine ischemic insult to the midgut, affecting single or multiple segments of the already developed intestine.
Intrauterine vascular disruption can lead to ischemic necrosis of the bowel with subsequent resorption of the affected segment or segments.
The hypothesis that most cases of jejunoileal atresia occur secondary to vascular disruption during fetal life is derived from experimental as well as clinical evidence.
Isolated mesenteric vascular insults and interference with the segmental blood supply to the small intestine were created in fetal dogs, and resulted in different degrees and patterns of intraluminal obstruction, reproducing the spectrum of stenosis and atresia found in humans.
Moreover, the presence of bile, lanugo hair, and squamous epithelial cells from swallowed amniotic fluid distal to an atresia suggests that the atresia occurs subsequent to some event, but that at some time in gestation the intestinal lumen was patent, thus allowing passage of these contents.
Additionally, atresias seen in association with other intrauterine vascular insults such as intussusception, midgut volvulus, thromboembolic occlusions, transmesenteric internal hernias, and incarceration or snaring of bowel in an omphalocele or gastroschisis have contributed to wide acceptance of this hypothesis.
The presence of associated extra-abdominal organ abnormalities in jejunoileal atresia is low (<10%) due to its occurrence later in fetal life and the localized nature of the vascular insult.
Rarely, jejunoileal atresia has been found in patients with Hirschsprung disease (HD), cystic fibrosis, malrotation, Down syndrome, anorectal and vertebral anomalies, neural tube defects, congenital heart disease, and other GI atresias.
Methylene blue, previously used for amniocentesis in twin pregnancies, has been implicated in causing small bowel atresia as well.
Although jejunoileal atresias are usually not hereditary, there is a well-documented autosomal recessive pattern of inheritance of multiple atresias.
In these cases, intestinal rotation was normal, mesenteric defects were never observed, and lanugo hairs and squamous cells were not identified distal to the most proximal atresia.
All these findings suggest an early intrauterine event.
Survival is poor in these infants, even with successful bowel resection.
No correlations have been found between jejunoileal atresia and parental or maternal disease.
However, the use of maternal vasoconstrictive medications, as well as maternal cigarette smoking in the first trimester of pregnancy, has been shown to increase the risk of small bowel atresia.
Chromosomal abnormalities are seen in fewer than 1% of the babies born with jejunoileal atresia.
H&A
How are intestinal atresias classified?
The Grosfeld classification system separates these defects into four groups, with an additional consideration for type III(b).
This classification has significant prognostic and therapeutic value, as it emphasizes the importance of associated loss of intestinal length, abnormal collateral intestinal blood supply, and concomitant atresia or stenosis.
Regarding classification, the most proximal atresia determines whether the atresia is classified as jejunal or ileal atresia.
Multiple atresias are found in up to 30% of patients.
Stenosis
Stenosis is defined as a localized narrowing of the intestinal lumen without disruption in the intestinal wall or a defect in the mesentery.
At the stenotic site, a short, narrow, somewhat rigid segment of intestine with a small lumen is found.
Often the muscularis is irregular and the submucosa is thickened.
Stenosis may also take the form of a type I atresia with a fenestrated web.
Patients with jejunoileal stenosis usually have a normal length of small intestine.
Type I Atresia
In type I jejunoileal atresia, the intestinal obstruction occurs secondary to a membrane or web formed by both mucosa and submucosa, while the muscularis and serosa remain intact.
On gross inspection, the bowel and its mesentery appear to be in continuity.
However, the proximal bowel is dilated while the distal bowel is collapsed.
With the increased intraluminal pressure in the proximal bowel, bulging of the web into the distal intestine can create a windsock effect.
As with stenosis, there is no foreshortening of the bowel in type I atresias.
Type II Atresia
The clinical findings of a type II atresia are a dilated, blind-ending proximal bowel loop connected by a fibrous cord to the collapsed distal bowel with an intact mesentery.
Increased intraluminal pressure in the dilated and hypertrophied proximal bowel may lead to focal proximal small bowel ischemia.
The distal collapsed bowel commences as a blind end, which sometimes assumes a bulbous appearance owing to the remains of an intussusception.
Again, the total small bowel length is usually normal.
Type III(a) Atresia
In type III(a) atresia, the proximal bowel ends blindly, with no fibrous connecting cord to the distal intestine.
A V-shaped mesenteric defect of varying size is present between the two ends of intestine.
The dilated, blind-ending proximal bowel is often aperistaltic and frequently undergoes torsion or becomes overdistended, with subsequent necrosis and perforation occurring as a secondary event.
In this scenario, the total length of the small bowel is variable (but usually less than normal), owing to intrauterine resorption of the affected bowel.
Type III(b) Atresia
Type III(b) atresia (apple-peel, Christmas tree, or Maypole deformity) consists of a proximal jejunal atresia, absence of the superior mesenteric artery beyond the origin of the middle colic branch, agenesis of the dorsal mesentery, a significant loss of intestinal length, and a large mesenteric defect.
The decompressed distal small bowel lies free in the abdomen and assumes a helical configuration around a single perfusing vessel arising from the ileocolic or right colic arcades.
Occasionally, additional type I or type II atresias are found distal to the initial atresia.
It has also been shown that type III(b) atresias are significantly more likely to present with volvulus and are at risk for impaired vascularity of the distal bowel.
This type of atresia has been found in families with a pattern suggestive of an autosomal recessive mode of inheritance.
It also has been encountered in siblings with identical lesions and in twins.
The occurrence of intestinal atresia in other siblings, the association of multiple atresias (15%), and the discordance in a set of apparently monozygotic twins may point to more complex genetic transmission for type III(b) atresias in around 20%.
Infants with this anomaly are often premature, and up to 50% may have malrotation.
Accordingly, there is increased morbidity (63%) and mortality (54%) in this population.
Type III(b) atresias are most likely the result of a proximal superior mesenteric arterial occlusion with extensive infarction of the proximal segment of the midgut.
Also, it can develop from a midgut volvulus.
Primary failure of development of the distal superior mesenteric artery has also been suggested as an etiologic factor. However, this is unlikely because meconium is usually found in the bowel distal to the atresia.
This finding indicates that the atresia develops after bile secretion begins, which occurs around week 12 of intrauterine life.
The superior mesenteric artery develops much earlier than 12 weeks.
Type IV Atresia
Multiple-segment atresias or a combination of types I to III are classified as type IV.
Up to one-third of infants affected with jejunoileal atresia present with multiple atresias.
The majority of cases of multiple-segment atresias are sporadic with no other family history of intestinal abnormalities.
They are likely a result of multiple vascular insults to the mesentery, intrauterine inflammatory processes, or a malformation of the GI tract occurring during embryonic development.
Embolic material from a nonviable fetus to a living monochorionic twin through placental vascular connections could also account for single or multiple intestinal atresias.
Associated defects, particularly abnormalities of the central nervous system, have been noted in approximately 25% of nonfamilial multiple intestinal atresia patients.
Multiple atresias have also been seen in association with severe immunodeficiency associated with a rare mutation in the tetratricopeptide repeat domain–7A (TTC7A) gene, which aids in the development of the thymus and intestinal epithelium.
A familial form of multiple intestinal atresia (FMIA) involving the stomach, duodenum, and both the small and large bowel has been described.
It is associated with prematurity and shortened bowel length. To date, it has been uniformly fatal.
It is associated with type I and II atresias, with type II predominating.
An autosomal recessive mode of transmission has been suggested for this familial condition because it is unlikely that an isolated prenatal vascular accident is responsible for such extensive involvement of the GI tract.
In addition, infants affected with this familial form are found to have long segments of completely occluded small or large intestine without a recognizable lumen.
Another pathognomonic feature seen in FMIA is the sieve-like appearance of the intestine on histologic examination where multiple lumina are surrounded by epithelial cells and muscularis mucosa.
H&A
How is jejunoileal atresia diagnosed?
The diagnosis of jejunoileal atresia can usually be made by radiographic examination of the abdomen using swallowed air as contrast.
Swallowed air reaches the proximal bowel by 1 hour and the distal small bowel by 3 hours in a normal vigorous infant in whom its passage is blocked, but this pattern may be delayed in premature or sick infants with poor sucking.
Proximal jejunal atresia patients can have a few gas-filled and fluid-filled loops of small bowel, but the remainder of the abdomen is gasless.
When the atresia is associated with cystic fibrosis, fewer air–fluid levels are evident, and the typical groundglass appearance of inspissated meconium is often seen.
A limited-contrast study may be useful if intestinal stenosis is suspected.
As haustral markings are rarely seen in neonates, distal ileal atresia may be difficult to differentiate from colonic atresia.
A contrast enema will reveal an unused appearance to the colon.
Reliance on intraoperative injection of saline into the large bowel to confirm distal bowel patency may fail to identify an associated colonic or rectal atresia.
If the small bowel atresia occurred late in gestation, the bowel distal to the atresia may have a more normal caliber.
Occasionally, air and meconium can accumulate proximal to an atresia, mimicking the radiologic appearance of meconium ileus.
In addition, total colonic aganglionosis can be difficult to differentiate from small bowel atresia.
Ten percent of babies with jejunoileal atresia present with meconium peritonitis.
The intestinal perforation usually occurs proximal to the obstruction, near the bulbous blind end.
The radiologic appearance of a meconium pseudocyst containing a large air–fluid level is related to the late intrauterine bowel perforation.
Intraluminal calcification of meconium or intramural calcification in the form of diffuse punctate or rounded aggregations have been reported with intestinal stenosis or atresia.
Meconium calcification in patients with hereditary FMIA produces a “string of pearls,” which is pathognomonic for this condition.
The clinical and radiologic picture of jejunoileal stenosis is determined by the level and degree of stenosis, and the diagnosis may be delayed for years.
Morphologic and functional changes in the proximal obstructed intestine vary depending on the degree of obstruction.
DIFFERENTIAL DIAGNOSIS
Diseases that mimic jejunoileal atresia include colonic atresia, midgut volvulus, meconium ileus, duplication cysts, internal hernias, ileus due to sepsis, birth trauma, maternal medications, prematurity, and hypothyroidism.
Special investigations including an upper GI contrast study, contrast enema, rectal biopsy, and a ΔF508 gene deletion assay or sweat test to exclude associated cystic fibrosis may be needed.
H&A
How is colonic atresia diagnosed and managed?
Colonic atresia is a rare cause of intestinal obstruction and comprises 2–15% of all GI atresias.
The reported incidence of colonic atresia varies greatly, from 1 in 5000 to 1 in 60,000 live births.
The accepted incidence is approximately 1 in 20,000 live births.
Although it is most commonly reported as an isolated anomaly, approximately one-third of babies have associated congenital lesions.
There are various classifications for colonic atresia, but the one most commonly used divides colonic atresia into three types.
Type I consists of mucosal atresia with an intact bowel wall and mesentery.
In type II, the atretic ends are separated by a fibrous cord.
In type III, the atretic ends are separated by a V-shaped mesenteric gap.
Type III lesions are the most commonly occurring lesions overall, while types I and II are seen more commonly distal to the splenic flexure.
The rate of associated anomalies with colonic atresia is much smaller when compared with other atresias.
Colonic atresias have been found in approximately 2.5% of neonates with gastroschisis.
There are fewer than 25 published cases of colonic atresia and HD.
Complex urologic abnormalities, multiple small intestinal atresias, an unfixed mesentery, and skeletal anomalies have also been reported with colonic atresia.
Similar to small bowel atresias, a vascular insult to the colon continues to be the accepted etiology for all types of colonic atresia.
The characteristic clinical features of colonic atresia are abdominal distention, bilious emesis, and failure to pass meconium.
On plain radiographs, air–fluid levels are usually appreciated as well as dilated intestinal loops of large bowel often associated with a “ground-glass” appearance of meconium mixed with air.
Occasionally, the dilation can be so massive that it mimics pneumoperitoneum.
The diagnosis is made with a contrast enema showing a small diameter distal colon that comes to an abrupt halt at the level of the obstruction.
The diagnosis of colonic atresia is an indication for urgent operative management, as the risk for perforation is higher than is seen in jejunoileal atresias.
The operative approach depends on the clinical status of the patient, the level of the atresia, any associated small intestinal atresias, and the patency of the bowel distal to the atresia.
It is important to exclude other intestinal atresias and stenoses at the time of operation, as they occur with some frequency.
A diagnosis of associated HD, although rare, must be made by frozen section analysis of rectal biopsies during the initial surgery as unrecognized HD can lead to an anastomotic leak or functional obstruction.
A staged approach consisting of colostomy with mucous fistula is generally preferred for colonic atresia. Because the proximal and distal ends adjacent to the atresia are abnormal in both innervation and vascularity, resection of the bulbous proximal colon as well as a portion of the distal microcolon is suggested.
Primary resection with anastomosis has a higher incidence of complications, usually due to undiagnosed distal pathology.
A recent report of a small case series of rectal and sigmoid atresias described a transanal approach for the repair of the atresias.
An initial colostomy at birth was performed followed by a transanal approach 3–6 months later.
Closure of the colostomy was then carried out 1–2 months later.
In the absence of other serious comorbidities, the prognosis in colonic atresia is excellent.
If diagnosed early, the overall mortality is <10%.
A delay in diagnosis beyond 72 hours, however, may result in a mortality of >60%. This high mortality is due, in part, to the formation of a closed loop obstruction between an intact ileocecal valve and the atresia, leading to massive colonic distention and perforation.
H&A
What type of duodenal obstruction may result in non-bilious emesis?
Annular pancreas cannot be differentiated from duodenal atresia or stenosis on plain films or contrast studies.
However, some case series have shown that annular pancreas is more likely to result in a preampullary obstruction presenting with non-bilious emesis, as well as in a partial versus total obstruction.
Annular pancreas may therefore account for a large portion of the 10%–15% of patients who present with a preampullary congenital duodenal obstruction.
For most of the first half of the twentieth century, annular pancreas was considered an extrinsic compression of the duodenum to be relieved by removing the annulus. Outcomes were uniformly poor.
It is now understood that annular pancreas does not produce duodenal obstruction by simple extrinsic compression, but rather due to a duodenal atresia or stenosis associated with the annular pancreas.
Therefore, a duodenoduodenostomy is also used to bypass this anomaly.
When performing the anastomosis, the surgeon should position the incisions on the duodenum approximately 1 cm away from the annulus on each side to avoid future compression of the anastomosis.
A classic example of an annular pancreas resulting in duodenal obstruction is shown in Figure 27.6.
Sherif
What is gastroduodenal emphysema?
A very rare, but extremely alarming, presentation of duodenal stenosis is gastroduodenal emphysema.
This is hypothesized to be caused by an increase in intragastric pressure, resulting in a breach of the gastroduodenal mucosa.
The breach allows air to enter the bowel wall. When seen in the setting of a partial duodenal obstruction, the condition is benign and should be differentiated from emphysematous gastritis, which may be seen due to ischemia or infection.
Decompressing the foregut with a nasogastric tube and repairing the underlying obstruction is adequate treatment for this condition.
Figure 27.8 demonstrates this presentation in a 9-month-old girl with Down syndrome.
Sherif
When should tapering be considered intraoperatively?
Tapering should be strongly considered if the proximal duodenum is severely dilated, redundant, and floppy.
This may both hasten postoperative recovery and prevent the risk of delayed dysfunction.
Figure 27.10 shows a tapering duodenoplasty performed at the time of duodenoduodenostomy for type I duodenal atresia.
Using an Endo GIA, the duodenum is tapered over an 18-mm Hegar dilator placed through the proximal duodenotomy.
Sherif
How should a concomitant rotational abnormality be managed in duodenal stenosis/atresia patients?
The concept of potential midgut volvulus resulting in a partial duodenal obstruction cannot be emphasized enough.
Most bowel obstructions are considered more serious and require intervention sooner if they are complete.
The exception is duodenal obstruction. The differential diagnoses of a partial duodenal obstruction are duodenal stenosis, annular pancreas (which can be partial or complete), and midgut volvulus.
Duodenal obstruction is actually a very common presentation of midgut volvulus in neonates and infants.
The differential diagnoses cannot be elucidated on plain films. Therefore, a baby presenting with bilious emesis and a partial duodenal obstruction on abdominal films should undergo either immediate exploration or an immediate UGI study.
Figure 27.11 demonstrates a midgut volvulus resulting in a partial duodenal obstruction in a 3-monthold girl. The plain films only showed the partial duodenal obstruction.
UGI clearly confirmed a volvulus and immediate exploration was undertaken.
Some type of rotational abnormality is found during operation in approximately 30% of patients with intrinsic congenital duodenal obstruction.
In these cases, the mesentery should be carefully examined and a Ladd’s procedure performed if required, concomitant with the repair of the duodenal obstruction.
Sherif
How is duodenal obstruction secondary to a hematoma or SMA syndrome managed?
Older patients who present with duodenal obstruction due to a duodenal hematoma or superior mesenteric artery syndrome are typically treated with nutritional support until the underlying process resolves.
This support is preferably given through a nasojejunal feeding tube placed under fluoroscopic guidance, but total parenteral nutrition is used if a tube cannot be passed.
Figure 27.12 shows a classic superior mesenteric artery syndrome. This occurred in a 13-year-old female oncology patient who developed bilious emesis and intolerance to oral feeding after losing almost 20 kg of weight following commencement of chemotherapy.
A sharp duodenal cutoff is seen at the third portion, just at the margin of the vertebral column.
A nasojejunal tube was advanced distal to the obstruction, to provide enteral feeding.
The patient’s bilious emesis resolved following a 3-kg weight gain, and she went on to tolerate a regular diet.
Sherif
