Omphalocele

Omphalocele (umbilical cord hernia, umbilical hernia, embryonic hernia) is a protrusion of abdominal organs through a midline defect at the base of the navel.

Omphalocele is a developmental anomaly in which, as a result of an early disruption of organogenesis, the abdominal organs develop to some extent outside the embryo's body, which entails not only abnormal development of these organs, but also defects in the formation of both the abdominal cavity and the chest. The hernial protrusion is covered by a hernial sac consisting of the amnion on the outside and the peritoneum on the inside, with mesenchyme (Varganov's jelly) between them.

In omphalocele, the protrusion of organs is covered by a thin membrane and may be small (only a few loops of bowel) or may contain most of the abdominal organs (intestine, stomach, liver). The immediate dangers are desiccation of the internal organs, hypothermia and dehydration due to evaporation of water, and infection of the peritoneum. Infants with omphalocele have a very high incidence of other congenital malformations, including intestinal atresia; chromosomal abnormalities such as Down syndrome; and cardiac and renal abnormalities, which should be identified and evaluated before surgical correction.

ICD-10 code

Q79.2. Exomphalos.

Epidemiology

The incidence of omphalocele is 1-2 per 10,000 live births, with no significant differences by gender. Most children with omphalocele are born full-term.

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What causes omphalocele?

The ideas about the ethology and pathogenesis of omphalocele still remain contradictory. It is believed that two factors play a major role in the genesis of embryonic hernia of the umbilical cord - impaired intestinal rotation in the first period of rotation and underdevelopment of the anterior abdominal wall. Impaired intestinal rotation manifests itself in the form of the preservation of a temporary "physiological" umbilical hernia, which forms in a 5-week embryo due to the discrepancy between the growth rates of the intestine and the abdominal cavity and disappears on its own by the 11th week of development.

Another theory is that omphalocele is a "persistence of the truncal stalk in the area normally occupied by the somatopleura." This idea of a failure of lateral mesodermal replacement of the peritoneum, amnion, and stalk mesoderm explains the variety of abnormalities seen in omphalocele, from cloacal exstrophy to pentad of Cantrell.

How does omphalocele manifest itself?

Children with omphalocele often have multiple combined defects of other vital organs and systems, as well as chromosomal abnormalities. Most often, these are congenital heart defects, kidney defects, orthopedic defects, etc. Small omphaloceles are often combined with a patent yolk duct.

A combination of omphalocele with Down syndrome and trisomy of chromosomes 13 and 18 is possible.

Omphalocele is a component of Beckwith-Wiedemann syndrome, also known as OMG syndrome (omphalocele-macroglossia-gigantism). This syndrome, in addition to omphalocele, is characterized (as the name suggests) by the presence of a large tongue, which sometimes causes difficulty breathing, and gigantism, most often realized in the gigantism of parenchymatous organs (hepatosplenomegaly, hyperplasia of the pancreas), which can manifest itself as hyperinsulinism and hypoglycemia, especially dangerous in the neonatal period. Partial gigantism of the skeleton is found less often.

Omphalocele is sometimes a component of such severe anomalies as Cantrell's pentad and cloacal exstrophy, the treatment of which is extremely difficult and still has disappointing results in most clinics. It is the severity of the combined lesions and their curability that determine the severity of the patient's condition with omphalocele and the prognosis, and in thanatogenesis or disability: the leading role often belongs not to the omphalocele, but to the combined malformations or genetic syndromes. All of the above dictates the need for early detection of omphalocele in the antenatal period for a timely decision on maintaining or terminating the pregnancy.

Classification

According to the working classification of omphalocele, depending on the size of the defect of the anterior abdominal wall (hernial orifice) and the volume of the contents of the hernial sac, omphalocele of small, medium and large sizes are distinguished. The contents of small and medium hernias are usually intestinal loops (in a small one - one or more). A large omphalocele always contains not only intestinal loops, but also the liver.

According to the shape of the hernial protrusion, hemispherical, spherical and mushroom-shaped hernias are distinguished.

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How to recognize omphalocele?

Visualization of omphalocele is possible with ultrasound from the 14th week of pregnancy. A test for the mother's alpha-fetoprotein (AFP) content is very informative; its content is elevated in congenital malformations. In this case (with an increase in the amount of AFP), it is necessary to carefully examine the fetus for the presence of combined congenital malformations. If omphalocele is detected in combination with incurable malformations or genetic anomalies, expectant parents may be advised to terminate the pregnancy.

Children with a small or medium omphalocele can be born naturally if there are no other indications for a cesarean section. In the case of large omphaloceles, the method of delivery is chosen individually in each specific case. It is usually advisable to perform a cesarean section due to the risk of rupture of the thin membranes of the hernia.

Prenatal diagnosis of omphalocele

Diagnosis of omphalocele after the birth of the child, as a rule, does not cause difficulties. However, with a small omphalocele, errors may be made during the treatment of the umbilical cord in the maternity hospital, which have serious consequences. Usually, in the hernial membranes with this type of anomaly, there are one or two intestinal loops, i.e. the volume of the formation is small, and such an omphalocele often looks like a thickened umbilical cord. If the doctor or midwife did not recognize a small omphalocele and applied a crushing clamp or ligature to the border between the umbilical cord shadows and the skin, and cut off the remainder of the umbilical cord, then the intestinal wall may be damaged. Therefore, in doubtful cases (with a thick umbilical cord, dysplasia of the umbilical cord vessels), it is important to remember about small omphalocele and apply the ligature at a distance of at least 10-15 cm from the skin edge. Such a newborn requires immediate transfer to a surgical hospital for examination. A lateral X-ray examination allows confirming or excluding the diagnosis of a small omphalocele. In the case of an omphalocele, intestinal loops (gas bubbles) are detected in the umbilical cord membranes outside the anterior abdominal wall, whereas in the absence of communication between the abdominal cavity and the umbilical cord membranes, the integrity of the anterior abdominal wall is not compromised on the X-ray. Considering the fact that combined malformations are not uncommon with omphalocele, the mandatory patient examination protocol, in addition to X-ray of the chest and abdominal cavity in a vertical position, includes ultrasonography of the brain, abdominal cavity and retroperitoneal space, as well as ultrasound of the heart and large vessels.

Treatment of omphalocele

When giving first aid to a child with omphalocele in a maternity hospital, the main attention should be paid to maintaining his body temperature, protecting the hernial sac from adverse external influences. Patients with omphalocele need emergency care.

The choice of treatment method for omphalocele depends on the size of the hernia, the patient's condition and the capabilities of the hospital where this treatment is carried out. It can be conservative or surgical and take place in one or several stages.

Conservative treatment of omphalocele

In recent years, as resuscitation has developed and resuscitation support has improved, conservative treatment has been used in extremely limited cases when, for one reason or another, it is assumed that surgical intervention should be postponed. Such tactics can be used for huge umbilical cord hernias or their combination with multiple severe developmental defects. Most often, such tanning solutions as povidone-iodine, merbromin, and 5% potassium permanganate solution are used for these purposes. The hernial sac is fixed over the patient in a vertical position by the umbilical cord remnant, the hernia membranes are treated with one of the listed solutions several times a day, achieving the formation of a dense crust, under which a scar gradually forms, forming a large ventral hernia. However, this method has many serious disadvantages (infection of the membranes, their rupture, a long healing period, pronounced adhesions, etc.), so it should be used only in extraordinary cases.

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Surgical treatment of omphalocele

Surgical treatment can be radical (layer-by-layer suturing of all layers of the abdominal wall after immersion of organs into the abdominal cavity) or staged. The second option involves gradual formation of the anterior abdominal wall using auto- or alloplastic materials at intermediate stages.

Radical intervention is the operation of choice, performed in cases where the viscero-abdominal disproportion (the ratio between the volume of the hernial formation and the capacity of the abdominal cavity) is moderate, and layer-by-layer suturing of the anterior abdominal wall does not cause a significant increase in intra-abdominal pressure. Accordingly, radical surgery is usually performed for small and medium-sized omphaloceles, less often for large omphaloceles.

If a small omphalocele is combined with a vitelline duct, radical intervention is supplemented by resection of the vitelline duct. It should be remembered that a component of almost any omphalocele, with rare exceptions in small hernias, is malrotation, a common mesentery of the small and large intestines, therefore, when immersing organs into the abdominal cavity, the large intestine should move to the left flank, and the small intestine should be in the right flank and the center of the abdominal cavity. After completing the intraperitoneal stage of the operation, layer-by-layer suturing of the wound of the anterior abdominal wall is performed, forming a "cosmetic" navel.

The greatest difficulties arise in the treatment of large omphaloceles with a significant degree of viscero-abdominal disproportion, when radical surgery is impossible due to a sharp increase in intra-abdominal pressure. In such cases, various types of staged surgical treatment have to be used.

In 194S, Robert Gross from Boston described a method of staged surgical treatment of large umbilical cord hernias. The first stage consisted of removing the hernia membranes, immersing the organs, as far as possible, into the abdominal cavity, widely separating the skin flaps of the abdominal wall up to the lumbar region and suturing the skin with the formation of a ventral hernia. The second stage involved eliminating the ventral hernia (at the age of L-2 years). At present, this method is practically not used, since it has many disadvantages (pronounced adhesive process, large size of the ventral hernia, lack of conditions for increasing the volume of the abdominal cavity, since almost all the organs are in the skin hernial sac).

A major advance in the treatment of large omphaloceles occurred in 1967 when Schuster described a method of temporarily applying a plastic covering to reduce the size of the fascial defect.

Then in 1969, Allen and Wrenn proposed using a single-layer silastic covering, sutured to the edges of the fascial defect with subsequent gradual reduction in the volume of the hernial formation using manual compression, which allows for delayed primary closure of the hernial wall. As soon as the first stage of the intervention restores intestinal motility, it empties and decreases in volume, the second stage follows (usually after 3-14 days) - removal of the sac and radical plastic surgery of the anterior abdominal wall or the formation of a now small ventral hernia. This method remains the main one in the treatment of this pathology and is currently

Surgical technique for staged treatment of large omphalocele. The operation begins with an incision in the skin around the hernial formation. Having made sure that it is impossible to immerse all the organs, a silicone bag with a silastic coating is sutured to the muscular-aponeurotic edge of the defect of the anterior abdominal wall. This bag covers that part of the hernia contents that was successfully placed in the abdominal cavity. The bag is tied over the organs and fixed above the patient in a vertical position. As the organs from the bag spontaneously descend into the abdominal cavity, the bag is tied lower and lower (in relation to the abdominal wall), reducing its volume, while some degree of compression is allowed. The second stage involves removing the bag after 7-14 days) and radical layer-by-layer suturing of the anterior abdominal wall to form a small ventral hernia. In this case, the last stage of surgical treatment (elimination of the ventral hernia with layer-by-layer suturing of the abdominal wall) is performed at the age of 6 months.

There are methods that are successfully used for the use of allotransplantation of synthetic or biological origin, sewn into the fascial defect of the anterior abdominal wall in the form of a patch in case of a pronounced degree of visceroabdominal disproportion.

Postoperative management

In the early postoperative period, artificial ventilation of the lungs, pain relief, and antibacterial therapy are performed. The decisive component of treatment is total parenteral nutrition throughout the entire period of healing of the abdominal wall and restoration of bowel functions. In children with combined severe anomalies in the postoperative period, the issue of timely correction of these anomalies should be resolved, which requires the participation of doctors of these specialties in the treatment. Particular attention should be paid to patients with Besquit-Wiedemann syndrome, prone to severe hypoglycemia. Careful control of blood sugar levels helps prevent this condition and prevent the development of encephalopathy in such patients.

Prognosis of omphalocele

All patients with omphalocele who do not have lethal malformations of other organs and systems survive. However, when omphalocele is combined with various anomalies, their timely diagnosis, as well as cooperation with doctors of other specialties, allow not only to cure children with severe congenital heart defects, kidneys, central nervous system, musculoskeletal system, but also to provide them with an acceptable quality of life, which is possible only in a multidisciplinary children's hospital, all specialists and services of which have extensive experience in nursing newborns with this complex pathology. Dispensary observation of patients should be carried out until the full completion of rehabilitation for several years.