From the Guidelines
Approximately 33-50% of children under 2 years old with a unilateral inguinal hernia will develop a contralateral hernia. This estimate is based on the reported rates of contralateral patent processus vaginalis (PPV) identified at the time of inguinal hernia repair in infants younger than 1 year of age 1. The prevalence of PPV is highest during infancy and declines with age, which is why the risk of contralateral hernia development is higher in younger children.
Key Factors Influencing Contralateral Hernia Development
- Age: The risk of contralateral hernia development is higher in younger children, with reported rates decreasing from 64% in infants younger than 2 months to 15% by 5 years of age 1.
- Gestational age: Preterm infants are at higher risk of developing inguinal hernias, with an incidence of 13% in infants born at less than 33 weeks of gestational age 1.
- Family history: Although not explicitly stated in the provided evidence, family history may play a role in the development of inguinal hernias.
Implications for Clinical Practice
- Pediatric surgeons may recommend bilateral exploration and repair in infants presenting with a unilateral inguinal hernia, especially in those under 6 months of age, to prevent the need for a second surgery if a contralateral hernia develops later.
- The decision for bilateral exploration should be made on a case-by-case basis, considering factors such as the child's age, overall health, and family preferences.
- Parents should be counseled about the risk of contralateral hernia development and advised to monitor for signs of hernia on the opposite side, even after unilateral repair.
From the Research
Incidence of Contralateral Inguinal Hernia in Children Under 2 Years Old
- The incidence of contralateral inguinal hernia in children under 2 years old is reported to be around 10-13% in several studies 2, 3.
- A study published in 1998 found that the incidence of contralateral hernia in boys under 2 years of age was 13.7% 2.
- Another study published in 1999 reported that the incidence of metachronous contralateral hernia in children less than 2 years of age was 10.6% 3.
- A prospective study published in 2009 found that 23 (12%) of 196 patients less than two years old underwent contralateral herniorrhaphy in the follow-up period 4.
- However, the incidence of contralateral hernia can vary depending on factors such as age, gender, and prematurity, with some studies reporting higher incidence rates in certain subgroups 3, 5, 6.
Factors Influencing the Incidence of Contralateral Inguinal Hernia
- Age: The incidence of contralateral hernia is higher in younger children, with one study reporting a highly significant accumulation of consecutive hernias in children under 2 months old 6.
- Prematurity: Premature infants are at higher risk of developing contralateral hernia, with one study reporting a significant difference in the occurrence of contralateral hernia between preterm and term infants 4.
- Gender: The incidence of contralateral hernia may vary between boys and girls, with some studies reporting higher rates in boys 2, 3.