Understanding Pediatric Umbilical Hernias

US Pharm. 2022;47(12):17-20.

ABSTRACT: A hernia is a protrusion of an organ through the wall of a cavity in which it normally resides. Pediatric umbilical hernias affect an estimated 15% to 23% of children at birth. Umbilical hernias can be benign and undergo spontaneous closure by age 4 or 5 years. Patients with acute complications such as incarceration or strangulation require urgent surgical intervention. This article will discuss the etiology, epidemiology, risk factors, management, and complications associated with pediatric umbilical hernias.

When an infant is in utero, the umbilical cord is a critical structure that connects the fetus to the mother’s placenta. The umbilical cord contains one vein and two arteries, which provide critical nutrients during development in the womb. During development, the umbilical ring appears as early as the fourth week of gestation.¹ After childbirth, the cord is clamped and cut. Within a month, the remaining component of the cord naturally falls off, and the ring undergoes spontaneous closure. In some circumstances, there is an incomplete closure of the abdominal muscle and tissue (i.e., fascia) in the umbilical ring. With loss of fascial integrity, the intra-abdominal contents protrude through the weakened muscle near the belly button and result in a painful bulge called an umbilical hernia.² In some cases, the hernia can be pushed back into the opening or decrease in size when the patient is lying back, called a reducible hernia. A hernia can arise in the site above the navel (termed epigastric) or around the navel (termed umbilical). The exact etiology of developing an umbilical hernia is currently unknown but usually occurs through the umbilical vein component of the ring. Contrary to common belief, the method by which the umbilical cord is clamped or cut after birth does not influence the risk of developing an umbilical hernia. Other disorders of the umbilicus include patent urachus, omphalomesenteric fistula, and umbilical polyp.^2,3 It is important to recognize these defects as early as possible to prevent complications.

Epidemiology

The estimated incidence of umbilical hernias in the United States is approximately 15% to 23% of newborns (or 800,000 annually), with males and females represented equally.⁴ The occurrence of umbilical hernias is higher in African American infants compared with Caucasians, reportedly as high as 26.6%.⁵ Secondary to the weakened integrity of epidermis and immature development of internal organs, infants who are premature or of lower birthweight have an even greater risk of developing an umbilical hernia. For an infant weighing 1,000 g to 1,500 g, the incidence is as high as 84%, and for infants weighing 2,000 g to 2,500 g, the incidence is lower at 20.5%.⁶ Children with metabolic disorders (e.g., hypothyroidism), autosomal trisomies (e.g., trisomy 18 and 21), or dysmorphic syndromes (e.g., Beckwith-Wiedemann syndrome, Marfan syndrome) are also at greater risk of umbilical hernias.⁷

Although umbilical hernias are more common in pediatrics, they can also occur in adults as an acquired defect from conditions that increase intra-abdominal pressure, such as pregnancy, obesity, ascites, or chronic pulmonary disease.⁸ Although the previous conditions may be associated with the risk of developing an umbilical hernia, this condition commonly affects healthy infants without any predisposing factors.

History and Physical

Primary abdominal wall hernias can prove to be a diagnostic challenge. When an infant presents with a hernia, there should be a high index of suspicion for umbilical hernia diagnosis and prompt evaluation for surgical intervention to improve outcomes. When eliciting the history of a patient with suspected umbilical hernia, some subjective reports by caregivers may include swelling around or inside the belly button. Furthermore, due to pain from the hernia, the infant may cry, cough, or strain while defecating or urinating.^1,3 However, small, asymptomatic umbilical hernias may not be detected on clinical exam. If noticeable, the size of the umbilical hernia should be measured. The reducibility—the ability for the lump to be pushed back into the abdominal wall—should also be determined. The presence of signs of incarceration (parts of an organ that may protrude through the hernia) should be evaluated, as it may lead to a loss of blood supply to the affected bowel tissue (referred to as strangulation). Clinical signs that could indicate a hernia is incarcerated or strangulated umbilical hernia are when the child presents with severe abdominal pain, nausea, and vomiting, and physical exam will be significant for abdominal tenderness, distension, and skin erythema.⁵ No specific medical tests are required to make the diagnosis of umbilical hernias; it is primarily based on physical assessments.

Treatment

Despite the prevalence of umbilical hernias, the management is poorly studied. There are no consensus recommendations or practice guidelines regarding the timing and indications for surgical repair in asymptomatic patients.⁶ Repair of umbilical hernias in infants is typically postponed because a majority of them will undergo spontaneous closure by age 2 years and have a low rate of complications.⁸ One retrospective case series reported a 93% rate of spontaneous closure within the first year of life.⁹ Furthermore, relatively large hernias over 0.5 cm in diameter decreased in size by an average of 18% per month over the first year of life.¹⁰ Spontaneous closure later in childhood is less likely; therefore, if the hernia does persist after the age of 5 years, surgical intervention is often warranted.¹⁰ However, this recommendation is controversial, and there is no consensus on optimal time to repair asymptomatic hernias. An indicator that a hernia will spontaneously resolve is correlated to the size of the hernial ring. Those that are greater than 1.5 cm are more likely to persist into adult years.¹¹ One study reported that 95% of hernias with a defect <0.5 cm in infants undergo spontaneous closure, whereas 0% of hernias with defect of >1.5 cm undergo closure. In this instance, some pediatricians recommend repairing umbilical hernias with the defect of 1.5 cm or more in children aged 2 years or older because of the low rates of spontaneous closure.^12,13

In infants, an umbilical hernia is typically not a medical emergency except in the rare case when the intestine is squeezed into the hernia pouch, thereby cutting off blood supply to the intestine, causing strangulation. In addition, rupture of organs that are protruding through the hernia or signs of incarceration warrant urgent surgical correction.^3,6 In terms of timing of repair for umbilical hernias, the most urgent need for repair is a strangulated umbilical hernia for which surgery is required emergently. Incarcerated umbilical hernias are not as urgent as strangulated hernias, but due to the risk of progressing to a strangulated hernia these surgeries should by followed by repair soon after identification. The least urgent umbilical hernias are those that are reducible, for which repair can be delayed until age 4 to 5 years.^2,6,8

The surgery used to repair an umbilical hernia is a relatively simple procedure lasting less than an hour in the setting of no complications. Patients require general anesthesia to reduce the burden of pain while the operation is performed. It is usually performed as an open technique through infraumbilical skin incision.¹⁴ Sutures are required once the fascia is fully repaired. Umbilicoplasty, a procedure that changes the appearance of the belly button, may be performed specifically in those with a large umbilical hernia to improve the cosmetic results. To reduce the risk of hernia reoccurrence, mesh can be provided to support the weakened abdominal muscle.¹ Mesh is more commonly used in adult hernia repair, while pediatric repair is commonly performed without mesh and instead muscle tissue is connected to strengthen the weakened area.¹ A nonsurgical option that is available is called adhesive strapping, which can enhance early spontaneous closure of the umbilical hernia. However, adhesive strapping of the umbilicus is controversial, as some studies have been negative, demonstrating no efficacy for umbilical hernia closure and a higher risk of skin complications and restricted activity of the abdominal musculature.^15,16

Complications

The true incidence of complications associated with umbilical hernias is difficult to classify due to the selected studies evaluating complications, primarily biased to those who have undergone surgical intervention. Patients without surgical correction are underrepresented in the current body of literature. However, the body of evidence available suggests that the rates of complications of those with unrepaired umbilical hernia are relatively low, with the risk of incarceration estimated to be 0.07% to 0.3%.^5,17 Strangulation of umbilical hernias requiring bowel resection is rare but is reported in the literature.⁶ It is unknown if the rates of complications associated with umbilical hernias are influenced by age. One study of 590 children reporting incidence of incarceration was 3.7% in children aged younger than 1 year, 5.7% in children aged 1 to 3 years, 4.7% in children aged 4 to 7 years, and 4.7% in children aged 7 to 12 years, while others have not found any difference in age and rates of complications.^4,18 Furthermore, the rates of complications may also be influenced by size of the hernia; however, data are limited and not consistent throughout studies. Lassaletta et al found that defects from 0.5 cm to 1.5 cm had the highest incidence of complications with an incidence of 7.4%, whereas incidences for defects of <0.5 cm or >1.5 cm were 4.3% and 3.7%, respectively.¹⁸

In patients with surgical correction, postoperative complications are also very low. The complications that can be observed include infections (e.g., superficial wound infection and subcutaneous abscesses), scar formation, seromas, or hematoma of the surgical site. The rates of umbilical hernia reoccurrence are as low as 0.27% to 2.44%.⁴ Although the rates of complications from the surgical interventions are low, the risks associated with ancillary surgical facilitators such as anesthesia should not be overlooked. The risks of neurodevelopmental changes have been reported in a few studies, and the FDA has issued a warning for providers to consider delaying surgery when appropriate in pediatrics secondary to the risks of adverse neurologic sequelae.¹⁹ The American Academy of Pediatrics (AAP) has also released its own guidance that acknowledges the potential risks of anesthetics but states that the harms remain uncertain and consideration of the warning should be weighed against the risks and benefits of both anesthesia and the required surgical intervention. Umbilical hernia repair under the guidance of the AAP statement falls into the category of a procedure that could be reasonably delayed past 3 years of age to minimize the possibility of neurocognitive effects from anesthetics.²⁰

Enhancing Healthcare Team Outcomes

Identification of asymptomatic hernias and those patients who have the potential for spontaneous hernia closure is critical to avoid unnecessary surgical intervention and potential harms associated with infections or anesthetics.⁶ Furthermore, this would benefit healthcare systems by avoiding unnecessary costs of operative repairs. Parents may express a lot of concern over asymptomatic hernias, but communication about the potential harms of interventions and advising families about the natural course of umbilical hernias are of key importance. The management of an umbilical hernia requires an interprofessional team to help guide support for parents, patient management, infection prevention, and counseling. The key message to share with anxious parents is that the majority of pediatric umbilical hernias spontaneously close by age 5 to 7 years. The most important signs to be aware of are bowel obstruction, strangulation, or incarceration, for which referral to a pediatric surgeon is warranted.

Conclusion

A hernia forms due to a defect in the muscle and connective tissues within the abdomen. Hernia development can present as a noticeable abdominal bulge that can sometimes be painful when fat or contents of the bowel push through the defect. An umbilical hernia is a specific type of hernia caused by a defect of the abdominal wall near the belly button or umbilicus. In a newborn, an umbilical hernia occurs as a result of incomplete closure of the muscles around the umbilical cord.³ This finding, although worrisome to parents, is actually common during the first few months of life and often does not result in complications or require any treatment.³ However, for selected infants there may be undue risks associated with the presence of the hernia, and therefore it would require surgical intervention.¹ It is important to have a deeper understanding of the etiology and presentation of umbilical hernias in order to determine which situations necessitate surgical evaluation.

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