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Repair of Gastrointestinal Atresias
Blockages of the Stomach, Bowel and Bile Ducts

Atresia is the absence or marked narrowing of the lumen (the passage inside) of the gut (gastrointestinal tract) at birth. It may occur at any point in the gut.

Pyloric Atresia

Anatomy and Physiology

The stomach is a C-shaped organ that lies under the left lower ribs and upper part of the abdomen.

  • The stomach is divided into three parts (Figure 1):
    1. The cardia is the portion of the stomach that is adjacent to the esophagus
    2. The body of the stomach is the largest part and has two curvatures, the lesser curvature, which lies on the inside of the C, and the greater curvature, which lies on the outside of the C
    3. The pylorus lies at the end of the stomach
  • Food entering the mouth is passed into the esophagus and then goes into the upper end of the stomach. The stomach holds and mixes the food with gastric (stomach) juices that aid in digestion and then passes the mixture through the pylorus, a muscular sphincter or gate, that controls the passage of the stomach contents into the duodenum, which is the beginning of the small bowel
Figure 1 - Sectional anatomy of the stomach demonstrating the pylorus. © P. Montelone

Pathology

  • Pyloric atresia is usually a web of tissue incompletely obstructing the pylorus. This is due to incomplete recanalization (restoration of lumen) of the initially solid intestinal tract of the fetus (Figure 2)
  • The atresia may be longer resulting in a fibrous cord instead of a web
Figure 2 - Upper left. Sagittal section through the pylorus showing a web type of atresia. Upper right. Cross-section through the pylorus showing the web. Lower left. Fibrous cord atresia. Lower right. Fibrous cord atresia seen in cross-section.© P. Montelone

History and Exam

  • Symptoms are related to the degree of intestinal obstruction
  • A small opening may allow liquids to pass sluggishly or not at all with a high-grade obstruction
  • The newborn may present with nonbilious vomiting (no bile present to give golden brown color) and gastric distension
  • There may be failure to pass meconium (first bowel movement) if obstruction is high-grade
  • Examination usually shows a dilated upper abdomen

Tests

  • X-rays of the abdomen usually show excessive gas in the stomach with little or no gas in the small bowel and colon
  • A barium solution (barium contrast study) placed in the stomach shows obstruction of the pylorus
  • Endoscopy (see Panendoscopy) is usually not necessary

Indications for Surgery

The higher the grade of obstruction the sooner surgery will be necessary to allow feeding

Surgical Procedures

  • Surgery is performed under general anesthesia with careful monitoring in a warmed operating room.
  • In certain cases small webs may be broken up using an endoscope, a long lighted tube attached to a video monitor through which various instruments can be passed
  • The procedure performed is determined by the extent of the atresia. Possible procedures are:
    1. Pyloric web only - A small incision is made in the stomach wall (gastrotomy, (Figure 3A) at level of the web with excision (removal) of the web. The remaining intestinal tract is inspected for additional anomalies. A catheters is passed through the duodenum from the gastrotomy incision to assure that the entire duodenum is open (Figure 3B). The stomach wall is then sutured closed (Figures 3C and 3D)
    2. Fibrous cord artresia - Usually the procedure used to bypass the fibrous cord is called a gastroduodenostomy in which the side of stomach wall is sutured to the side of the duodenum and an opening made between the two (Figure 4), or a gastrojejunostomy in which the side of the stomach is sewn to the side of jejunum
  • The entire intestinal tract is investigated
Figure 3a - Longitudinal incision made through the wall of the pylorus to expose a web atresia. © P. MonteloneFigure 3b - The web is removed and a catheter passed into the duodenum to make sure there are no other atresias. © P. Montelone
Figure 3c - The incision may be sutured transversely. © P. MonteloneFigure 3d - The incision may be sutured longitudinally. © P. Montelone
Figure 4 - A bypass for food is formed by making an opening in the side of the stomach and in the duodenum beyond the atresia and the two organs sutured together (gastroduodenostomy). The bypass may be between the stomach and jejunum (gastrojejunostomy). © P. Montelone

Complications

  • Bleeding
  • Respiratory distress
  • Hypothermia - low body temperature
  • Low urine output
  • Infection
  • Bowel obstruction
  • Complications associated with any major operation

Post Op Care

  • The child is cared for in an intensive care unit with:
    1. Special monitoring to ensure adequate breathing since the child may require ventilator support
    2. Temperature monitoring
    3. Urine output monitoring
  • Fluids are given by vein until food is tolerated
  • A tube is placed through the nose into the stomach to keep the stomach decompressed
  • Antibiotics are given top prevent infection
  • Prolonged intensive care may be required

After Care

  • These children may be hospitalized for long periods and require special follow up
  • The goal is a healthy baby able to eat, urinate, and eliminate stool at the time of discharge without need for respiratory or special nutritional support
  • Follow up is determined by the complexity of the atresia

Duodenal Atresia

Anatomy and Physiology

  • The duodenum is the first part of the small bowel and connects the stomach to the jejunum, which is the second part of the small bowel (Figure 5)
  • The duodenum is retroperitoneal (has peritoneum, the thin layer of tissue that lines the abdominal cavity) only on the anterior (front) side, It is fixed in location and wraps around the head, neck and body of the pancreas
  • It is divided into four parts:
    1. The first part joins the stomach
    2. The ampulla of Vater (entrance site into duodenum of the joined common bile duct and pancreatic duct) enters the medial (towards the midline) side of the second part of the duodenum. The accessory pancreatic duct enters slightly higher in the medial wall of the duodenum
    3. The superior mesenteric artery and vein (major blood vessels for the bowel) pass anterior to the third part
    4. The fourth part joins the jejunum
  • The ligament of Treitz (a supporting band of peritoneum and muscle fibers) marks the point between the duodenum and jejunum
  • The duodenum produces many hormones that help regulate digestion
    1. Liver bile and pancreatic secretions are added to the bowel through the ampulla of Vater
    2. The actual passage and presence of food in the duodenum starts the flow of hormones, bile and pancreatic secretions. By the time food leaves the duodenum most of the ingredients necessary for digestion have been added
    3. Little digestion (breakdown of food) and absorption (passage of nutrients from the bowel into the blood) take place in the duodenum
Figure 5 - Anatomy of the duodenum showing the relationship to the stomach, jejunum and ileum. © C. McKee

Pathology

  • During development, the duodenum begins as a solid cord that undergoes recanalization of the solid center leaving a lumen
  • The failure to recanalize occurs during the 4th - 5th week of gestation in approximately 1 in 10,000 births. These defects will usually occur below the ampulla of Vater
  • It accounts for about 1/3 of all atresias
  • Associated anomalies are common
  • Duodenal atresia may present in one of three ways (Figure 6):
    1. Type I - there is a mucosal web with normal muscular wall (most common)
    2. Type II - characterized by a short fibrous cord connecting two atretic ends of duodenum
    3. Type III - there is complete separation of the atretic ends
Figure 6 - Types of duodenal atresia. See text. © P. Montelone

History and Exam

  • These newborns present with early vomiting of bile stained material because the atresia is usually below the ampulla of Vater
  • There is failure to pass meconium (the first bowel movement of a newborn) from the rectum
  • Abdominal examination may reveal mild upper abdominal distension
  • Other anomalies may be apparent

Tests

  • X-ray examination of abdomen will frequently show the "double bubble" sign, air in the stomach and proximal (upper) duodenum only
  • A barium solution (barium contrast study) placed in the stomach shows obstruction of the duodenum

Indications for Surgery

  • All infants require surgical correction to restore intestinal continuity
  • Surgery would be performed as soon as the diagnosis is established and the infant is stable

Surgical Procedures

  • Surgery is performed under general anesthesia with careful monitoring in a warmed operating room
  • The type of defect determines the surgical procedure:
    1. Type I - The web can be treated by incision into the wall of the duodenum with excision of the web followed by suture of the wall (Figure 7)
    2. Type II - A duodenum to duodenum bypass is created around the atretic cord (called a duodenoduodenostomy) (Figure 8)
    3. Type III - A duodenoduodenostomy or gastrojejunostomy is carried out to bypass the atretic segment (Figure 8)
Figure 7 - Left. The wall of the duodenum is opened and the web removed. Right. The wall the then sutured closed.© P. Montelone
Figure 8 - Bypasses for duodenal atresia. Upper. The atretic segment of duodenum is removed and the two ends sutured together (duodenoduodenostomy). Lower. The atretic segment is bypassed by creating an opening between the stomach and jejunum (gastrojejunostomy). © P. Montelone

Complication, Post-operative Care and After Care

  • Same as for Pyloric Atresia

Jejunoileal Atresia

Anatomy and Physiology

  • The jejunum and ileum are the second and third parts of the small bowel (Figure 5)
  • The jejunum, ileum, and associated mesenteries (supporting and suspending structures) are attached to the back wall of the abdomen. The jejunum and ileum are mobile organs that move within the abdomen
  • They are completely covered with peritoneum (single layer of cells that line the surface of the abdomen and bowel)
  • The ligament of Treitz (a supporting band of peritoneum and muscle fibers) marks the point between the duodenum and jejunum
  • The ileum joins the cecum (first part of the colon) in the right lower quadrant at the ileocecal valve near the appendix (Figure 5)
  • The arterial blood supply of the entire small bowel except for the first portion of the duodenum is the superior mesenteric artery
  • The functions of the small bowel are digestion, absorption, hormone production, and antibody production

Pathology

  • Jejunoileal atresias are complete obstructions of the jejunum or ileum
  • They are caused by arterial and venous abnormalities in the mesentery of the bowel of the fetus
  • They are more common in the jejunum, equal in males and females and may be single or multiple in nature
  • Associated anomalies are less common than in duodenal atresias
  • Jejunoileal atresias are classified as follows (Figure 9):
    1. Type I - a web or diaphragm of the mucosa (inner lining of the bowel)
    2. Type II - an atretic cord exists between two blind ends of bowel with an intact mesentery
    3. Type IIIa - a complete separation of the blind ends of the bowel by a V shaped mesenteric gap
    4. Type IIIb - an apple peel deformity in which the distal bowel receives retrograde blood supply from the right colic or ileocolic artery
    5. Type IV - multiple atresias
Figure 9 - Types of jejunoileal atresia, See text.© P. Montelone

History and Exam

  • These anomalies present with bilious vomiting and abdominal distension
  • There is frequently no passage of meconium (the first bowel movement of a newborn)

Tests

  • X-ray examination frequently shows many air-fluid levels in the small bowel and possibly a very small colon (microcolon)
  • A barium solution (barium contrast study) placed in the stomach shows obstruction of the jejunum or ileum
  • Fetal ultrasound may diagnose the condition before birth

Indications for Surgery

  • All infants require surgical correction to restore intestinal continuity
  • Surgery would be performed as soon as the diagnosis is established and the infant is stable

Surgical Procedures

  • Surgery is performed under general anesthesia with careful monitoring in a warmed operating room
  • The type of defect determines the surgical procedure:
    1. Type I
    • An incision is made into the bowel wall at the level of the web, the web removed and the bowel wall sutured (jejunoplasty)
    • Alternately the abnormal bowel is resected (removed) and the cut ends of the bowel anastomosed (sewn together)
    1. Type II - IV - Atretic bowel segment is removed with anastomosis (cut ends sutured together)

Complication, Post-operative Care and After Care

  • Same as for Pyloric Atresia

Biliary Atresia

Anatomy

  • The liver is the largest gland in the body representing about one-twentieth of body weight at birth (Figure 10)
  • This organ is essential for producing and breaking down many essential body substances including the production of bile that aids digestion.
  • The liver is composed of two major lobes (right and left) that are further subdivided into segments
  • Blood enters the liver from two sources, the hepatic artery and the portal vein. The latter drains the gut. Lobular segmentation also holds true for the arterial and portal venous inflow and the bile duct drainage of the liver
  • The venous drainage of the liver empties into the inferior vena cava that flows into the heart
  • The porta hepatis of the liver is the site where the hepatic artery, portal vein and common bile duct begin their branching to enter the substance of the liver
  • The common bile duct drains into the duodenum through the ampulla of Vater
Figure 10 - Anatomy of the liver. Note the large right lobe and the small left lobe. Also shown are the bile ducts, hepatic artery and portal vein that enter the liver at the porta hepatis. © P. Montelone

Pathology

  • Biliary atresia is thought to be due to progressive fibrosis and scarring of the bile ducts both inside and outside the liver possibly due to a virus
  • The incidence is approximately 1 in 15,000 births and associated anomalies are common
  • This process leads to progressive back up of bile flow which ultimately has toxic effects upon the liver (biliary cirrhosis)
  • The majority of cases show fibrous collapse of the gall bladder and a fibrous common bile duct

History and Exam

  • These newborns are jaundiced (yellowish skin) at birth
  • Examination may be entirely normal except for the jaundiced skin color

Tests

  • Blood tests reveal abnormal liver function and elevated bilirubin (bile)
  • Ultlrasound examination of the abdomen may demonstrate a contracted gall bladder and common bile duct. Dilatation of the ducts within the liver may be seen

Indications for Surgery

These infants are usually operated upon by two months of age to prevent progressive bile duct fibrosis and minimize biliary cirrhosis

Surgical Procedures

  • The preferred operation is a Roux en Y hepatoportoenterostomy (Kasai procedure, Figure 11)
    1. The fibrous cord representing the hepatic bile duct outside the liver is separated from the surrounding tissues up to the porta hepatis
    2. The liver at the porta hepatis is cut back to expose normal bile duct tissue
    3. A limb of jejunum is sewn into the porta hepatis
  • Liver transplantation is required in many cases
Figure 11 - See text for description. © P. Montelone

Complication, Post-operative Care and After Care

  • Same as for Pyloric Atresia