Pediatric Umbilical Hernia

Etiology

In children, umbilical hernias occur due to the incomplete closure of the umbilical ring fascia, allowing intraabdominal contents to protrude through it.[3] 

Following the separation of the umbilical cord, the fascial ring usually undergoes natural closure due to the growth of the rectus muscles and fusion of the fascial layers. However, if this process is hindered or delayed, it can result in the development of an umbilical hernia.

Although the exact etiology is unknown, however, it is believed to involve a dysfunction related to the umbilical vein component of the fascial ring.[4]

In addition to prematurity and low birth weight, other disorders that are associated with pediatric umbilical hernias include:

• Ascites
• Autosomal trisomies, such as trisomies 13, 18, and 21
• Childhood obesity
• Dysmorphic conditions (Beckwith-Wiedemann, Down, Ehlers-Danlos, and Marfan syndromes)
• Hypothyroidism
• Mucopolysaccharidoses
• Peritoneal dialysis[1][3][5][6][7][8][9]

The hernia may also originate slightly above the umbilicus, in which case it is more accurately referred to as an epigastric hernia.

The technique used for clamping or cutting the umbilical cord after birth does not have any impact on the potential development of an umbilical hernia in the future.

Other umbilical disorders include a patent urachus, umbilical polyp, cysts, granulomas, urachal remnants, and omphalomesenteric fistula. These abnormalities and similar conditions are more comprehensively described in our companion reference article on "Anatomy, Abdomen, and Pelvis: Umbilical Cord" available in StatPearls.[10]

Gastroschisis and omphalocele are abdominal wall disorders that bear some resemblance to umbilical hernias. Gastroschisis is characterized by a paraumbilical abdominal wall defect typically containing the bowel. Omphalocele is characterized by protrusions of abdominal organs and contents through the umbilicus covered only by a thin layer of peritoneum. They are individually described in their respective companion reference articles on "Gastroschisis" and "Omphalocele" in StatPearls.[11][12]

Epidemiology

Umbilical hernias are a prevalent condition among children. It is estimated that approximately 15%-23% of all newborns (approximately 800,000 neonates per year in the United States) have umbilical hernias. However, this percentage gradually decreases to 2%-10% by the time the child attains the age of 1 year.[13]

Umbilical hernias affect both boys and girls equally, with no significant gender-based differences in occurrence.[14][15][16]

The underlying reasons for the higher occurrence of umbilical hernias in the African-American infant population, with reported incidence rates as high as 26.6%, are not yet well understood.[16]

Pediatric umbilical hernias are significantly more prevalent in premature and low-birth-weight infants compared to neonates with normal maturity and weight.[1]

The incidence of pediatric umbilical hernias can be as high as 84% in newborn infants weighing between 1,000 and 1,500 grams, whereas it decreases to 20.5% in infants weighing between 2,000 and 2,500 grams at birth.[1][17]

Pathophysiology

During fetal development, the primitive umbilical ring emerges as early as the fourth week of gestation on the ventral surface of the body. The umbilical ring comprises the umbilical blood vessels (containing 1 vein and 2 arteries), the allantois, the vitelline duct, vitelline vessels, and a loop of the midgut. As the herniated midgut returns to its proper position, the definitive umbilical cord begins to develop, consisting of the umbilical vessels encased within a protective substance known as Wharton's jelly.

After birth, the umbilical vessels undergo obliteration and are subsequently replaced by a ligamentous structure.[18] 

Congenital disorders of the umbilicus encompass umbilical hernia, patent urachus, omphalomesenteric fistula, and umbilical polyp. Identifying these abnormalities as early as possible is crucial to minimize potential complications.[18] 

If the umbilical ring fails to close and obliterate after the separation of the umbilical cord, it will increase the risk of developing an umbilical hernia.

The umbilicus also serves as a relatively vulnerable area in the abdominal wall and is susceptible to herniation due to chronic elevation of intra-abdominal pressure.[18]

Neonatal hernias larger than 5 mm in size typically exhibit an average closure rate of 18% per month within the first year following birth.[19]

History and Physical

During a routine well-child visit, parents may report the presence of a bulging or swelling in the baby's belly button area to the child's pediatrician. This bulge tends to become more prominent when the baby cries, coughs, or strains.

The umbilical hernia might not be immediately evident upon direct examination. However, an important indication could be a history of the infant experiencing crying or apparent discomfort during bowel movements or urination.[20]

During the medical evaluation, it is essential to measure the size of the umbilical hernia defect, assess its reducibility, and carefully observe for any signs of incarceration or strangulation. The size of the fascial defect is a more reliable indicator of spontaneous closure potential than the size of the hernia sac or the degree of its protrusion.

Patients with incarcerated or strangulated umbilical hernias typically exhibit symptoms such as severe abdominal pain, nausea, and vomiting. During the physical examination, abdominal tenderness, distension,  skin erythema, and potentially an acute abdomen may also be observed in these cases.[16]

Evaluation

No specific medical testing or imaging is necessary to diagnose pediatric umbilical hernias, as the diagnosis is primarily based on the history provided by the parents and the findings from the physical examination.

Rare associated comorbid conditions often found with this condition include trisomies (13, 18, and 21) and metabolic disorders (such as hypothyroidism and mucopolysaccharidoses). In addition, various dysmorphic syndromes, including Beckwith-Wiedemann, Down, Ehlers-Danlos, and Marfan, have also been observed as comorbidities in this condition.[1][5][6][7][8]

However, it must be noted that most pediatric umbilical hernias occur in otherwise normal children.

Treatment / Management

Indications and Surgical Timing

Repairing umbilical hernias in infants is typically delayed because complications are uncommon, and a significant majority (>90%) of these hernias close spontaneously within 2 years.[19] 

The size of the hernia fascial defect provides a useful indicator for spontaneous closure. Typically, hernias with ring diameters less than 1 cm are significantly more likely to resolve independently than those larger than 1.5 cm.[21] (B2)

The expectant management of asymptomatic umbilical hernias until the age of 4 to 5 years is considered safe and is regarded as the standard care approach followed by many pediatric hospitals.[1] (A1)

Surgery is indicated for the following umbilical hernia patients:

• Ascites
• Bowel injury or perforation
• Hernia rupture
• Incarceration
• Large trunk-like hernia protrusion with a fascial defect that has not closed or improved by the age of 2 years
• Metabolic disorders (hypothyroidism and mucopolysaccharidoses) and genetic syndromes (Beckwith-Wiedemann, Down, Ehlers-Danlos, and Marfan)
• Peritoneal dialysis
• Persistent fascial defect by the age of 5 years
• Skin erosion, maceration, or excoriation over the hernia defect
• Strangulation
• Symptomatic
• Trisomies 13, 18, and 21 [1][3][5][6][7][8][9]
(A1)

Many suggest that surgical repair should be performed on any umbilical hernias with a defect size of 1.5 cm or more in children older than 2 years because of the relatively limited chance of spontaneous closure in such cases.[22][23] On the other hand, some experts recommend waiting until the child reaches the age of 5 years before considering surgical repair for asymptomatic umbilical hernias, irrespective of the degree of protuberance or size of the fascial defect.[1](A1)

In some instances, a surgical repair may also be considered for umbilical hernias if there is an unusually extensive protrusion of the hernia, the family is experiencing significant distress, or the child requires a general anesthetic for another medical indication.

In addition, local anesthetic infiltration and ultrasound-assisted rectus sheath blocks can be utilized as alternatives to general anesthesia in young children. These approaches help mitigate the risks and potential complications associated with the use of general anesthesia.[16] A comparison was conducted between local anesthetic infiltration and an ultrasound-guided rectus sheath block technique. Rectus sheath blocks involve the administration of local anesthetic to the nerve that travels between the posterior rectus sheath and the rectus muscle through infiltration.[16] This administration effectively provides anesthesia to the umbilical area, equivalent to the standard local anesthetic infiltration technique.[16] In the past, rectus sheath blocks were not commonly used due to the risks associated with blind infiltration. However, the introduction of intraoperative ultrasound has made rectus sheath blocks a viable and safer alternative. Both these methodologies—local anesthetic infiltration and rectus sheath blocks—demonstrate comparable analgesic effectiveness and similar incidence of adverse effects.[16]

In a 2018 study examining variations in the timing of pediatric umbilical surgery, several findings were observed:[24](A1)

• White children were more likely to undergo early surgery (before the age of 2 years) compared to Black children or children from other ethnic backgrounds.
• Patients covered by Medicaid and those residing in more rural areas tended to have earlier surgeries for umbilical hernias.
• Even after accounting for the factors above, the state of residence of the patient remained a stronger predictor of undergoing hernia surgery at an earlier age.

The findings highlight the significant disparities in surgical patterns for pediatric umbilical hernias. They underscore the importance of developing national, formal, and consensus-based best practice guidelines. Such guidelines would assist primary care physicians, pediatricians, and surgeons in establishing a more balanced approach, considering the risks associated with early surgery in very young children and the potential complications arising from unrepaired hernias.

Interestingly, studies have shown that spontaneous closure of pediatric umbilical hernias can occur even up to the age of 14 years.[25](B2)

Due to the lack of high-quality, prospective, population-based comparative studies, there is a continued absence of established best practice guidelines regarding the optimal timing of surgical intervention in asymptomatic pediatric umbilical hernias. As a result, the controversy surrounding this issue is likely to persist.

Surgical Technique

The standard approach for pediatric umbilical hernia repair commonly involves an open surgical procedure, which takes less than 1 hour to complete and is performed under general anesthesia.[4][13] (B2)

The surgical technique involves the following steps:

• The hernia is usually approached through an infra-umbilical incision, although a supra-umbilical incision may also be used.
• The hernia sac is identified and carefully dissected free from any adhesions until reaching the fascial ring.
• The sac is also dissected free from the umbilicus.
• If there are any hernia sac contents, they are returned to the peritoneal cavity.
• In cases of incarcerated bowel, opening the sac may aid in reduction.
• The surgeons may use an interrupted or continuous suture to close the fascial defect.
• Most surgeons typically prefer nonabsorbable sutures, particularly for larger defects or recurrent hernias.
• When fascial reapproximation without tension is not feasible or when the abdominal muscle is weakened or attenuated, a mesh may be used electively for larger defects.
• Mesh is used more frequently in adult umbilical hernia repairs, whereas, in pediatric cases, muscle tissue is sometimes used to reinforce weakened areas instead of mesh.
• Suturing the umbilicus to the fascia can enhance the cosmetic outcome, particularly in cases where larger hernias are present.
• A formal umbilicoplasty involving excess umbilical and peri-umbilical skin excision is rarely necessary.
• The use of pressure dressings after the procedure is optional. They are primarily intended to minimize postoperative complications such as seroma or hematoma formation.

The repair can also be performed using a laparoscopic approach; however, it is worth noting that this method tends to be less cost-effective and time-consuming compared to the open approach. However, the laparoscopic approach offers certain advantages, such as allowing for a comprehensive inspection of the abdominal cavity, removal of any urachal remnants or cysts by the surgeon, and identification and correction of any other abnormalities that may otherwise go unnoticed.

An alternative approach known as transumbilical repair has also been described, which offers benefits such as minimized scarring and improved cosmesis. This technique does not significantly increase the risk of complications compared to other approaches.[26] Studies have reported increased patient and parent satisfaction with the cosmetic results achieved through the transumbilical repair approach compared to standard repair methods.[26] 

Nonoperative Umbilical Strapping

There is conflicting information regarding umbilical strapping as a treatment for pediatric umbilical hernias. Although it is generally considered by most experts to be relatively ineffective, a number of studies have reported potential benefits in prompting early spontaneous hernia closure.[27][28][29][30][31][32]

Adverse effects include a relatively high rate of associated skin complications, such as irritation, maceration, and excoriation, which have been reported in approximately 25% of patients undergoing umbilical strapping for pediatric umbilical hernias.[27][29] The strapping may also restrict the normal activity of the abdominal musculature. 

Due to the lack of consensus on this issue, the absence of definitive prospective studies, the benign natural history of the underlying disorder with spontaneous closure occurring in most cases, and the ongoing controversy, formal recommendation for umbilical strapping as a treatment for pediatric umbilical hernias cannot be made at this time.

 Summary

• Pediatric umbilical hernias that are symptomatic or otherwise complicated should be repaired through surgical intervention.
• Regular reevaluation of hernias, especially between the ages of 2 and 4, is recommended.
• Parental concerns, comorbidities, and access to quality healthcare may influence the timing of surgical correction of the hernia.
• Larger hernias (> 1.5 cm, but < 2 cm in diameter) at 2 years of age may have a lower likelihood of spontaneous closure compared to smaller defects.
• Even larger defects have demonstrated spontaneous closure in the pediatric age group.
• Most studies do not indicate a correlation between hernia defect size and the risk of complications.
• There are conflicting opinions regarding the repair of asymptomatic pediatric umbilical hernias before the age of 5 years.
• While experts often favor waiting due to the high spontaneous closure rate and relatively low risk, opinions vary.
• Surgery for pediatric umbilical hernias typically involves open primary suture repair. However, a laparoscopic approach can also be performed.
• The use of mesh in repair procedures is optional, but it is generally recommended in complicated cases and recurrent hernias or for repairing larger defects.

Differential Diagnosis

Differential diagnosis includes the following:

• Epigastric hernia

• Hernia of the umbilical cord

• Omphalocele

• Pediatric hydrocele and hernia surgery

• Varicocele in adolescents

Prognosis

The prognosis for this condition can be listed as:

• Most pediatric umbilical hernias are asymptomatic; over 90% of these hernias will resolve spontaneously without any intervention by the time the child reaches age 5.
• Those pediatric umbilical hernias that become symptomatic before the child is 5 years old will require surgical intervention.
• Recurrence rates of umbilical hernias tend to be higher in those children who underwent surgical repair before they attained 4 years.
• Umbilical hernia surgical repairs have a low overall postoperative complication rate. 

Complications

Many studies examining the complications of umbilical hernias are often subject to a significant selection bias as they primarily focus on patients who have undergone surgical correction, inadvertently excluding the larger proportion of asymptomatic patients.

The prevailing consensus suggests that the likelihood of complications arising from an unrepaired umbilical hernia remains exceedingly low.[16][33] The estimated overall risk of incarceration is typically estimated to range from 0.07% to 2.77%.[16]

Studies have indicated that in cases where surgery is performed for umbilical hernias, the incidence of complications is approximately 4 times higher among patients younger than 4 years.[34]

Reported complications associated with umbilical hernia surgery include superficial wound infections, which occur in less than 1% of cases, and occurrences of hematomas and seromas. In the event that an abscess forms, it may be necessary to perform a drainage procedure.

Long-term follow-up studies have reported a recurrence risk of approximately 2% following umbilical hernia surgery.[13]

Prolonged ileus can occur after umbilical hernia surgery, particularly in younger children with larger hernia defects.