Abdominal Wall Surgical Anomalies in Infants and Children:

In the womb, the abdominal wall of the fetus is formed by 4 folds consisting of cephalic, caudal and 2 lateral folds. The anterior abdominal wall develops from the somatic part of these folds and the internal organs develop from the splanchnic layer.

Cephalic fold: This fold extending forward contains the foregut and forms the pharynx, esophagus and stomach. The somatic layer forms the thorax, epigastrium wall and primitive diaphragm. If the cephalic fold develops incorrectly, epigastric omphalocele occurs and is found together with cleft sternum, diaphragmatic defect, pericardial defect and cardiac anomalies, this syndrome is called Cantrel Pentalogy.

Caudal fold: The caudal fold, which extends posteriorly and is smaller, forms the hindgut and allantois. The colon and rectum develop from the hindgut. The splanchnic layer covers the anterior surface of the hindgut. The somatic layer forms the allantois, bladder and hypogastric abdominal wall. If the caudal fold develops incorrectly, hypogastric omphalocele, hindgut agenesis (anal atresia) and bladder exstrophy occur.

Lateral folds: Together with the splanchnic and somatic layers, they form the lateral abdominal walls and the umbilical ring. In the event of a developmental error at the end of the 3rd week of the lateral folds, the umbilical ring remains open and omphalocele or umbilical cord hernia occurs as a result. In omphalocele and gastroschisis, the muscular development of the anterior abdominal wall is normal. If there is no developmental defect, all folds progress towards the umbilical ring in the 12th week, with the intestines returning into the abdomen, and form the umbilical ring in a way that allows physiological herniation. In the intrauterine period, within the umbilical ring; There are omphalomesenteric canal, urachal canal, umbilical vein, umbilical arteries.

In summary, the pathologies that will develop due to developmental errors of the anterior abdominal wall are as follows;

• Omphalocele
• Gastroschisis
• Omphalomesenteric canal anomalies
• Epigastric hernia
• Diastesis recti
• Paraumblical hernia
• Umblic hernia
• Lateral hernias
• Spigiel hernia
• Inguinal hernias
• Urachal anomalies
• Congenital pubic sinus
• Bladder exstrophy
• Cloacal anomaly
• In this article, information will be given about Gastroschisis and Omphalocele.

Omphalocele (Exomphalos)

It is the herniation and protrusion of the abdominal organs from the location of the umbilical ring into an avascular (vascular-free) sac consisting of the peritoneum and anion (there is Warton's jelly between the two membranes). The umbilical cord is located at the top of the sac. The sac is usually not ruptured (torn) at birth and due to its transparent structure, the organs inside the sac can be easily seen. These organs can be the small and large intestines, stomach, liver, spleen, even the pancreas and bladder. Omphaloceles smaller than 4 cm in diameter are called umbilical cord hernias, omphaloceles between 4-6 cm are called small omphaloceles, and those larger than 10 cm are called giant omphaloceles.

 

Since the sac is avascular, it loses its vitality shortly after birth and ruptures easily. Especially in giant omphaloceles, the omphalocele sac may rupture before birth, during birth, or immediately after birth, and these are defined as ruptured omphalocele. If the sac ruptures before birth, sac remnants are found on the eviscerated organs, the intestines appear dull, and the walls are edematous and thick. Ruptured omphalocele should not be confused with gastroschisis.

What is the Frequency of Omphalocele and What are the Associated Anomalies?

The disease is seen in 1 in 3000-10000 live births, more frequently in boys than in girls. An accompanying anomaly is found in approximately 50% of cases. Multi-system anomalies are common. Heart anomalies (tetralogy of Fallot, ASD, VSD) are seen in 18-30% of cases. Digestive system rotation anomalies, Meckel diverticulum, intestinal and anal atresia, intestinal duplications, diaphragmatic hernia, meningomyelocele may accompany. Again, there are serious chromosomal anomalies (Trisomy 13, 15, 18, less commonly Trisomy 21) at a rate of 10-38%. On the other hand, there are syndromes defined together with omphalocele.

Beckwith-Wiedeman syndrome (EMG syndrome): It is found in approximately 12% of omphalocele cases. Omphalocele is accompanied by macroglossia, gigantism, hypoglycemia, and rarely chromosomal anomalies. There are 2 other syndromes defined together with omphalocele.

1- Upper midline defect syndrome: The syndrome is defined by this name because it was defined by Cantrell. Epigastric omphalocele, sternal cleft, diaphragmatic hernia, ectopia cordis, heart anomaly are the components of the syndrome.

2- Lower midline defect syndrome: In this syndrome, anomalies such as hypogastric omphalocele, vesicointestinal fissure, imperforate anus, colon agenesis and bladder exstrophy are found together.

Can omphalocele be diagnosed in the womb, what should be done if diagnosed?

Intrauterine diagnosis of abdominal wall defects is possible with the use of ultrasonography in routine pregnancy follow-up, as in many anomalies. The presence of a sac and the liver seen in the sac on ultrasonography suggest omphalocele, while the presence of large intestines floating in the amnion and small intestine atresia suggests gastroschisis. Fetal echocardiographic studies should be performed especially in babies with omphalocele to investigate cardiac anomalies.

Serum alpha-fetoprotein levels are significantly increased compared to normal pregnant women. Alpha-fetoprotein was found to be 100% increased in gastroschisis and 89% in omphalocele.

As with other surgical congenital anomalies, babies with omphalocele and gastroschisis should be delivered in an appropriate pediatric surgery center. The general approach to birth is normal birth. However, there are those who advocate that babies with giant omphalocele should be delivered by cesarean section to prevent rupture of the sac.

Amniocentesis and karyotype analysis should be performed in these cases to investigate chromosomal anomalies.

What are the Precautions to be Taken in the Early Period Following Birth?

After ensuring that the baby is born under suitable conditions, there are three important issues that need to be done before the surgery. It is appropriate for the baby to be born in a hospital with pediatric surgery clinics. These are to prevent heat and fluid loss and to prevent the sac from becoming infected. Excessive heat and fluid loss occurs especially in ruptured omphalocele and gastroschisis. A nasogastric tube is inserted to prevent vomiting and aspiration, thus preventing intestinal distension and providing easier reduction. An intravenous line should be opened from the upper extremity immediately and fluid therapy should be started. The fluid should be approximately 2.5-3 times the daily requirements of normal babies.

If the baby is born in a hospital without a pediatric surgery clinic, the omphalocele sac should be wrapped in sterile gases soaked in physiological serum and povidone iodine, the baby should be placed in an incubator or radiant warming system as soon as possible and transported to the pediatric surgery clinic. If the birth has taken place in a center where there is no pediatric surgery, and especially if the baby is to be transported to a distant center, in addition to the above, the baby should be wrapped in sterile plastic or aluminum foil up to the baby's neck to prevent evaporation and heat loss from the intestines. Broad-spectrum antibiotics should be started and vitamin K should also be administered to prevent contamination.

How is Omphalocele Treated?

The treatment of omphalocele is surgical. The aim of surgery is to place the organs that have come out of the sac or ruptured sac into the abdominal cavity and to surgically close the opening in the abdominal wall. Sometimes, accompanying serious anomalies (such as cardiac, chromosomal anomalies) and giant omphaloceles do not allow the external organs to be pushed into the abdomen and primary closure. In giant omphaloceles, the chest cavity is not well developed and lung hypoplasia may also be present. Placing the liver in the sac into the abdominal cavity may cause serious respiratory distress and may require mechanical ventilation treatment. When all these are taken into consideration, different treatment protocols can be applied.

Primary repair: It is an ideal method because it is a single-stage method and reduces the risk of infection and the length of hospital stay. This can be applied more easily in small omphaloceles where the liver is in the abdomen. During closure, intra-abdominal pressure should not exceed 20 cm H2O, otherwise, pressure on the diaphragm may cause respiratory distress, pressure on the inferior vena cava may cause decreased cardiac input, mesenteric venous stasis may cause circulatory disorders and ischemia in the intestines, and renal failure may occur by impairing renal blood flow. In addition, care should be taken not to twist the portal vein and inferior vena cava when placing the liver in the abdomen.

 

Staged Repair: It is performed in cases where primary repair cannot be applied for various reasons. This method was first described in 1948 and is based on the principle of closing the defect with a skin flap. The skin is released from the edges of the defect and the skin is closed without closing the fascia. Sometimes this is not possible either, in which case the silo technique described by Schuster in 1967 is applied. In this method, a synthetic material is sewn to the edge of the defect and a synthetic pouch is created outside the abdomen. This pouch is twisted a little every day and the defect is closed in 7-10 days.

Conservative Treatment: Primary surgery can cause serious problems in babies with giant omphalocele and serious additional anomalies. In these cases, antiseptics such as mercury chromide, silver nitrate, silver sulfadiazine and alcohol are applied to the sac. In this way, the sac remains sterile, dries, thickens and contracts on itself, and the organs inside are pushed into the abdominal cavity. In the meantime, the new epithelium advancing from the edge of the defect closes the entire defect by shedding the dried parts on the sac. 60-100% of patients can be treated with this method, but it takes 10-20 weeks for the sac to completely epithelialize. This increases the possibility of the sac becoming infected and ruptured, thus extending the hospital stay. In addition, the mercury chromide applied can cause mercury poisoning. In this application, a ventral hernia occurs on the anterior abdominal wall and these hernias need to be surgically treated in the following years.

 

What Kind of Complications May Develop During the Treatment Process in Omphalocele Patients?

There are 2 basic elements that determine the success of the treatment and the risk of developing complications. One of these is the presence of an accompanying additional anomaly and the severity of the anomaly, and the other is the width of the omphalocele. If there is no additional anomaly and the opening is small, the success is close to 100% and the complication rate is very low. On the contrary, very serious complications and death may occur. These complications are incision hernia if not completely closed, infection, sepsis and death, necrotizing enterocolitis and intestinal perforation, long-term total parenteral nutrition requirement and complications related to these are the main complications.

In addition,

Early Complications:

Mechanical obstruction: Very rare. Ileus findings encountered in the clinic are usually due to prolonged postoperative ileus (functional). If there is a suspicious situation, an upper GI contrast study should be performed.
Malrotation, if not corrected during surgery, later leads to duodenal obstruction and volvulus at a rate of 30%.

Postoperative necrotizing enterocolitis is observed in some cases.
Enteric fistulas may develop.
Inguinal hernia development has been reported after repair of abdominal wall defect;

Mid-Term Complications:

Increased intra-abdominal pressure may lead to gastroesophageal reflux. Nissen Funduplication may be necessary in 4-5% of cases.
Due to low intra-abdominal pressure in the fetal period, the probability of undescended testicles is high in these patients.

Late-Term Complications:

Long-term problems with intestinal function are rare. (Malabsorption). Intestinal functions return to normal within 6 months postoperatively.
Growth and developmental delay: In these patients, height and weight percentiles may be lower than their peers; they are around 3-15% at one year of age and 50% at ten years of age.
In 1/3 of these patients, IQ is <90, these complications may be due to prematurity and low birth weight. Since these children have malrotation (dislocation of the intestines), inversion appendectomy must be performed in the first surgery. Because the cecum is not in the right lower quadrant, if the child has acute appendicitis in the future, the outcome may be poor. If the baby does not have a genitourinary anomaly that may require bladder augmentation, appendectomy should be performed.

What is gastroschisis?

It is the herniation of the abdominal organs through the opening of the umbilical ring, which can be of different sizes, to the outside of the abdomen without any membrane. The defect diameter is usually between 2-4 cm, lateral to the umbilical cord, often to the right. There is healthy skin between the defect and the umbilical cord. There is no sac covering the defect. The organs that are eviscerated (protruding) are the small intestine, large intestine and stomach. Since the eviscerated organs are in contact with the amniotic fluid in the intrauterine period, the intestinal walls are edematous, thick and dull in appearance.

 

What is the Frequency of Gastroschisis, What are the Accompanying Anomalies?

Gastroschisis is seen in approximately 1 in 30,000 live births and is relatively more common in males. The rate of serious additional anomalies is low in gastroschisis. However, intestinal atresia can be seen in 10%. The rate of premature birth is quite high in gastroschisis (50-75%), while this rate is quite low in omphalocele. The prenatal follow-up, delivery (normal delivery is performed) and emergency treatment principles required after delivery in gastroschisis are the same as for ruptured omphalocele.

Can Gastroschisis Be Recognized in the Womb, What Should Be Done If Recognized?

What is valid for omphalocele in this regard is also valid for gastroschisis.

What are the Precautions to be Taken in the Early Period Following Birth?

What is valid for omphalocele in this regard is almost also valid for gastroschisis, but there is a small but important detail that needs to be paid attention to. These babies should definitely be born in hospitals with pediatric surgery clinics. Because the abdominal cavity in babies is well-developed and the rate of additional anomalies is low, and the opening is small. If intervention is performed immediately after the baby is born, all the intestines easily enter the abdomen without contacting the air for a long time and the abdomen is closed at once. However, if this is not done, the process valid for omphalocele begins.

How is Gastroschisis Treated?

Since the abdominal cavity develops better than omphalocele and the liver does not herniate, the organs are placed in the abdominal cavity more easily and the abdominal wall is closed. Although rare, the staged repair and silo method described in omphalocele may be required.

What are the Care and Complications After Gastroschisis Surgery?

If gastroschisis is treated in a timely manner, the complication rate is low. However, if intervention is not performed in a timely manner, the complications valid for omphalocele are also valid for gastroschisis.

What are the General Differences Between Omphalocele and Gastroschisis?

These differences are summarized in the table below.

*** The information provided here and the content of the website are designed to inform visitors, especially families. No information should be considered as advice by visitors and should not lead to any decision or action. The patient should definitely be examined by a pediatric surgeon on the subject, and a decision should be made by consulting him/her and consulting his/her personal information.