Discussion

This study sought to examine the clinical outcomes and complications of umbilical hernias as well as to identify factors for spontaneous resolution among children. In our study population, nearly half experienced spontaneous resolution of hernia by 4–5 years of age. The low rate of strangulation and incarceration suggests that if left untreated, umbilical hernia may resolve by itself. The low rate of perioperative complications (n=33; 1.26%) and reoccurrence (n=20; 0.76%) further suggests that repair is a safe procedure, even after 4–5 years of age. These findings are consistent with a recent American study, which stated that the rate of preoperative complications in umbilical hernia (eg, incarceration, strangulation, and evisceration) were low, occurring in approximately 1 in 1500 hernias. Overall, our study findings suggest that patients with asymptomatic umbilical hernia can be followed up safely by their family physician until 4–5 years of age, at least at our institution. Caution should be exercised when generalizing our results to other institutions across Canada.

Our study demonstrated that for every 1 mm increase in defect size, the odds of spontaneous resolution of umbilical hernia decreased by 5%. Despite 89.1% of hernias closing spontaneously at age 6, a study conducted by Walker and colleagues found that larger hernias were also less likely to close; in fact, 0% (0/21) with a defect >1.5 cm were closed by 6 years of age.10 In contrast, hernia prevalence may decrease with increasing age, indicating that the majority of large hernias may close by ages 3–4 without the need for surgery.11 Although not statistically significant in our study, prior literature attests that comorbidities, such as childhood obesity, may impact the likelihood of spontaneous closure.3 Interestingly, in our study, 40% of men and 38.7% of women had spontaneous resolution of umbilical hernia; however, when examining results of the logistic regression, this difference based on gender is not statistically significant. In other words, at least in our sample, there is no difference in frequency of spontaneous resolution of umbilical hernia among men versus women.

Premature babies were 80% less likely to have a spontaneous resolution compared with non-premature babies in our study. This may be due to incomplete closure of the fascia of the umbilical ring, through which abdominal contents may protrude. The umbilical ring undergoes spontaneous closure through the growth of rectus muscles and fusion of the fascial layers after separation of umbilical cord. The failure or delay in process can lead to the umbilical hernia formation.4

As supported by Halleran and colleagues, we surmised that unplanned hospital visits among families of young children (<4 years) could be diverted if patients with asymptomatic umbilical hernia were followed up by their family physicians conservatively.7 This might decrease the waiting time or eliminate the need for pediatric surgeon consultation in-hospitals because active patient monitoring by family physicians via conservative treatment strategies could potentially reduce unintended, adverse clinical outcomes.

The main limitation of this study was the retrospective design, which does not permit data collection on additional variables that could influence defect size and rates of recurrence or postoperative complications. Moreover, there were considerable data missing on defect size. As such, we were unable to provide a recommendation for a clinical cut-off for defect size in non-resolution cases. This large and robust sample is only reflective of one institution’s experience, in children aged 0–18 years and thus cannot be generalized to children in other institutions. Overall, our findings contribute to a field that has received minimal empirical attention.

Strengths of this study include identifying factors for spontaneous resolution of umbilical hernia. This information can help family physicians at CHEO when deciding which patients will have higher chances of spontaneous resolution and thus, which patients will benefit from an earlier surgical intervention or if it is recommended to be followed conservatively. Another advantage is the thorough collection of data regarding the progress of patients from the time of first admission until discharge, validated by the study team. The data collected therefore provide an accurate representation of clinical indicators and management of umbilical hernia at one Canadian Hospital.

Results from this study demonstrate that pediatric umbilical hernias are unlikely to become strangulated or incarcerated. The probability of spontaneous resolution of umbilical hernia decreases with an increase in defect size while controlling for prematurity and other comorbidities. On the other hand, probability of non-resolution increases with prematurity. In light of these findings, factors such as prematurity and increasing defect size should continue to be considered during the management of children with umbilical hernia in Ontario. Because umbilical hernias are usually a benign condition with a very low complication rate, family physicians should encourage parents to monitor their child’s condition until 4–5 years of age while being cognizant of any potential complications. Overall, conservative management is justifiable and appropriate during pediatric monitoring of asymptomatic umbilical hernia.

In conclusion, we aimed to characterize the probability of spontaneous resolution for umbilical hernia in our Eastern Ontario cohort. Overall, our study determined that the odds of spontaneous resolution were lower for premature babies and were negatively correlated with defect size. As such, continued monitoring of defect size and prematurity is warranted during umbilical hernia management of children in Ontario.