Incidence

The incidence of hernias in the pediatric population ranges from 0.8% to 4.4%. Hernias are more common in boys than girls by a factor of 5, with a predilection to the right side in 60%. Approximately 10% to 15% may occur bilaterally, and this is more often observed in premature infants. Hernias are more common overall in premature infants, with an incidence of 2% in girls and up to 30% in boys. It has been reported that the incidence of incarceration within 6 months of birth may approach 30% in premature infants, thus underscoring the necessity of immediate evaluation and planning for possible surgical intervention.

The occurrence of communicating hydrocele is difficult to separate from that of a hernia because they often coexist due to similar pathophysiology. Although simple, noncommunicating hydroceles may be seen in almost 80% of newborn boys, noncommunicating hydroceles are seen in at least 5% of male neonates per a study by Osifo and colleagues when they observed hydroceles in boys presenting for neonatal circumcision.

Pathophysiology

The development of the inguinal canal is contingent on the codevelopment of the coelomic cavity and the descent of the gonad in the case of male gender. As the abdominal wall develops, extensions of each layer contribute to the anatomic structure of the inguinal canal and the spermatic cord.

As the gonad passes through the inguinal canal, a portion of the peritoneum evaginates and follows the path of the testis and gubernaculum. This continuous extension of peritoneum is known as the processus vaginalis. The processus vaginalis ultimately develops into the visceral and parietal layers of the tunica vaginalis. In the case of female gender, the gubernacular equivalent will become the ovarian and round ligaments. Should the processus vaginalis remain patent in girls, it then becomes known as the canal of Nuck. Patency of the processus vaginalis and subsequent formation of hernia or hydrocele has been associated with prematurity, low birth weight, connective tissue anomalies, cystic fibrosis, posterior urethral valves, and other syndromic disorders.

Girls more rarely present with hernias, which is classically represented by the focal enlargement of the labia or groin. The ovary may compose part of the herniated contents. One percent of the time, the gonad will be found to be a testis, which occurs in boys with complete androgen resistance, formerly known as testicular feminization. In this rare disorder, a phenotypic girl, often during an evaluation for amenorrhea, will be found to have a normal XY male karyotype, bilateral intra-abdominal testes, and a foreshortened vagina.

The continuity of the processus vaginalis should obliterate above the level of the gonad, thus eliminating unrestricted access between the potential space within the groin and scrotum and the intraperitoneal contents. It has been reported that complete closure of the processus vaginalis on both sides was observed in only 18% of full-term infants; however, it must be noted that this was an autopsy study of only 19 stillborn infants. A narrowly patent conduit will allow only fluid, thus creating a hydrocele, which is a fluid accumulation within the tunica vaginalis. A widely patent conduit may allow fluid, omentum, bowel, gonads, and so forth, thus creating a hernia.

Hernia

Most children with hernias will present with indirect hernias: the hernia sac traverses through the inguinal canal, lateral to the inferior epigastric vessels as a consequence of a patent processus vaginalis. The diagnosis of direct hernia, a weakness of the abdominal wall protruding through the floor of the inguinal canal, is rare in children.

Associations with the increased risk for a patent processus vaginalis include prematurity, male gender, and increased abdominal pressure as a result of ventriculoperitoneal shunting, peritoneal dialysis, or ascites. In a recent study, Chen and colleagues noted a 13.3% incidence of inguinal hernia repair in 7379 patients with ventriculoperitoneal shunt compared with 4.1% in age-matched controls.

Hydrocele

Hydrocele may be reactive or nonreactive and communicating or noncommunicating. A communicating hydrocele reflects a patent processus vaginalis from the peritoneal cavity to the scrotum or labia. A noncommunicating hydrocele indicates successful postnatal obliteration of the proximal processus vaginalis. This condition is common in infants, and most are reabsorbed before 1 year of age; therefore, observation is clinically appropriate.

A reactive hydrocele, in contrast, is the result of the accumulation of fluid caused by trauma, infection, or other inflammatory conditions. A hydrocele of the spermatic cord results when the neck of the tunica vaginalis obliterates but the processus vaginalis remains patent. Abdominoscrotal hydrocele is the result of retrograde extension of the hydrocele sac into the abdomen. Abdominoscrotal hydroceles have been reported to obstruct the ureters or result in testicular dysmorphism. In some cases, an abdominoscrotal hydrocele may preclude circumcision due to the substantial size.

Metachronous Hernia

The potential occurrence of metachronous hernia is a subject that continues to raise contention in the urologic literature. A review of 918 patients who had undergone contralateral exploration of an asymptomatic side noted a 57% rate of patency of the processus vaginalis. When age is a consideration, infants aged less than 2 months had a 63% patency rate.

However, it is also understood that postnatal obliteration of the processus vaginalis contributes to a decreased prevalence of patency with increasing age. Rowe and colleagues found that the processus vaginalis will spontaneously close in 40% of children within a few months of birth and in 60% of children by 2 years of age. The incidence of a contralateral patent processus vaginalis must be reconciled with the true incidence rate of metachronous symptomatic hernia.

Although some might advocate for immediate surgery to prevent possible incarceration and the need for an operation in the future, others contest that exploration poses an unnecessary risk to the contralateral groin. Ron and colleagues noted that 10 explorations would have to be performed to prevent 1 metachronous patent processus vaginalis. In a review of 904 unilateral hernia repairs, Given and colleagues noted only a 5.6% incidence of contralateral hernia. This finding is supported by a review of the literature performed by Nataraja and colleagues in which they found that the overall risk of a metachronous hernia seems to be 5.76%.

To avoid exploration of the contralateral side, surgeons have used ultrasonography, diagnostic laparoscopy, and insufflation of the abdomen. The Goldstein method exploits the access to the intraperitoneum at the time of ipsilateral hernia repair. Simple insufflation of the intraperitoneal space via the hernia sac allows visual confirmation of patency of the contralateral processus vaginalis. Diagnostic laparoscopy has been hailed as highly accurate and sensitive. A recent meta-analysis noted a 99.4% sensitivity and 99.5% specificity ; however, it constitutes a necessary expense related to the surgical equipment. Some have found ultrasound to be useful in the evaluation of the opposite groin. Chen and colleagues found ultrasound to be 97.9% accurate in assessing patency of the processus vaginalis when they used the criteria of a 4-mm widening of the internal ring. However, this practice is not commonly performed.

Clinical Evaluation

An adequate history is imperative to not only establish the diagnosis but to determine the acuity of presentation. Parents may report a bulge in the groin, scrotum, or labia. It may be waxing and waning in nature with crying or straining. The inability to reduce the contents in association with pain, nausea, or vomiting is a significant finding and may require prompt surgical attention. However, typical presentation is that of a boy with painless enlargement of the scrotum or groin.

Thorough physical examination is an essential component of accurate clinical assessment of a child with a hernia. It is important to examine the child in both standing and supine positions. Hernias may be reducible, irreducible, or strangulated. Spontaneous closure will not occur in grossly apparent hernias, which necessitates referral for surgical repair.

Adequate history and physical examination should supplant radiographic evaluation; however, ultrasound may be used in cases of clinical uncertainty. If there is suspicion of a torsion of gonadal structures, evaluation by a urologist or pediatric surgeon should be sought immediately.

Indications for Treatment

The consequences of delayed presentation are incarceration and strangulation. A single surgeon review of more than 6000 cases observed a 12% incidence of incarceration at a mean age of 1.5 years. The risk of incarceration is more pronounced in premature infants, thus requiring definitive surgical planning. A study from Libya evaluated the impact of delayed surgical repair after the reduction of incarcerated inguinal hernias in a pediatric population when circumstances precluded immediate repair. Gahukamble and colleagues reported a similar overall complication rate for those undergoing immediate (within 72 hours) and delayed (within 1 to 3 months) repair. However, the repeat incarceration rate was nearly 16% in those with delayed management. Fortunately, improvements in pediatric anesthesia have rendered operative mortality to nil even in the setting of emergency surgery.

Treatment

The aim of surgery is to obliterate the conduit between the peritoneal cavity and groin. Because the pathophysiology of hydrocele and hernia is similar in the infant and child, they are both generally approached from the groin rather than the scrotum or labia. Ligation of the processus vaginalis at the level of the internal inguinal ring will provide adequate repair in most cases.

Although clinically apparent hernias and many communicating hydroceles necessitate surgical intervention, simple hydroceles are only generally repaired if they have not resolved by 2 years of age or if they are associated with discomfort, secondary inflammation, or parental desire.

The literature reports a 1.2% to 3.8% recurrence rate, with more than half occurring within the first year of initial surgical repair. Risk for recurrence is related to the setting of increased abdominal pressure and the presence of an incarcerated hernia, which may complicate the repair because of tissue edema. Grosfeld and colleagues reported a 12% recurrence rate of hernias in children with ventriculoperitoneal shunts. The population of children with reasons for elevated intra-abdominal pressures, such as shunts, ascites, and peritoneal dialysis, require special attention in the postoperative course.

Recommendations

The ability to differentiate between operative and nonoperative interventions is imperative in the evaluation of the acute and subacute groin/scrotum. Motives for referral include grossly apparent hernia, the history or incident of incarceration of hernia contents, and those in whom diagnosis is in question. Risk of hernia is highest in boys, children who are premature, or in the setting of increased intra-abdominal pressure. Noncommunicating hydrocele will typically resolve before 1 year of age. Referral for hydrocele should occur in the instance of nonresolution after 1 year or in the circumstances of communicating hydrocele or inflammatory features.

Incidence

The incidence of hernias in the pediatric population ranges from 0.8% to 4.4%. Hernias are more common in boys than girls by a factor of 5, with a predilection to the right side in 60%. Approximately 10% to 15% may occur bilaterally, and this is more often observed in premature infants. Hernias are more common overall in premature infants, with an incidence of 2% in girls and up to 30% in boys. It has been reported that the incidence of incarceration within 6 months of birth may approach 30% in premature infants, thus underscoring the necessity of immediate evaluation and planning for possible surgical intervention.

The occurrence of communicating hydrocele is difficult to separate from that of a hernia because they often coexist due to similar pathophysiology. Although simple, noncommunicating hydroceles may be seen in almost 80% of newborn boys, noncommunicating hydroceles are seen in at least 5% of male neonates per a study by Osifo and colleagues when they observed hydroceles in boys presenting for neonatal circumcision.

Pathophysiology

The development of the inguinal canal is contingent on the codevelopment of the coelomic cavity and the descent of the gonad in the case of male gender. As the abdominal wall develops, extensions of each layer contribute to the anatomic structure of the inguinal canal and the spermatic cord.

As the gonad passes through the inguinal canal, a portion of the peritoneum evaginates and follows the path of the testis and gubernaculum. This continuous extension of peritoneum is known as the processus vaginalis. The processus vaginalis ultimately develops into the visceral and parietal layers of the tunica vaginalis. In the case of female gender, the gubernacular equivalent will become the ovarian and round ligaments. Should the processus vaginalis remain patent in girls, it then becomes known as the canal of Nuck. Patency of the processus vaginalis and subsequent formation of hernia or hydrocele has been associated with prematurity, low birth weight, connective tissue anomalies, cystic fibrosis, posterior urethral valves, and other syndromic disorders.

Girls more rarely present with hernias, which is classically represented by the focal enlargement of the labia or groin. The ovary may compose part of the herniated contents. One percent of the time, the gonad will be found to be a testis, which occurs in boys with complete androgen resistance, formerly known as testicular feminization. In this rare disorder, a phenotypic girl, often during an evaluation for amenorrhea, will be found to have a normal XY male karyotype, bilateral intra-abdominal testes, and a foreshortened vagina.

The continuity of the processus vaginalis should obliterate above the level of the gonad, thus eliminating unrestricted access between the potential space within the groin and scrotum and the intraperitoneal contents. It has been reported that complete closure of the processus vaginalis on both sides was observed in only 18% of full-term infants; however, it must be noted that this was an autopsy study of only 19 stillborn infants. A narrowly patent conduit will allow only fluid, thus creating a hydrocele, which is a fluid accumulation within the tunica vaginalis. A widely patent conduit may allow fluid, omentum, bowel, gonads, and so forth, thus creating a hernia.

Hernia

Most children with hernias will present with indirect hernias: the hernia sac traverses through the inguinal canal, lateral to the inferior epigastric vessels as a consequence of a patent processus vaginalis. The diagnosis of direct hernia, a weakness of the abdominal wall protruding through the floor of the inguinal canal, is rare in children.

Associations with the increased risk for a patent processus vaginalis include prematurity, male gender, and increased abdominal pressure as a result of ventriculoperitoneal shunting, peritoneal dialysis, or ascites. In a recent study, Chen and colleagues noted a 13.3% incidence of inguinal hernia repair in 7379 patients with ventriculoperitoneal shunt compared with 4.1% in age-matched controls.

Hydrocele

Hydrocele may be reactive or nonreactive and communicating or noncommunicating. A communicating hydrocele reflects a patent processus vaginalis from the peritoneal cavity to the scrotum or labia. A noncommunicating hydrocele indicates successful postnatal obliteration of the proximal processus vaginalis. This condition is common in infants, and most are reabsorbed before 1 year of age; therefore, observation is clinically appropriate.

A reactive hydrocele, in contrast, is the result of the accumulation of fluid caused by trauma, infection, or other inflammatory conditions. A hydrocele of the spermatic cord results when the neck of the tunica vaginalis obliterates but the processus vaginalis remains patent. Abdominoscrotal hydrocele is the result of retrograde extension of the hydrocele sac into the abdomen. Abdominoscrotal hydroceles have been reported to obstruct the ureters or result in testicular dysmorphism. In some cases, an abdominoscrotal hydrocele may preclude circumcision due to the substantial size.

Metachronous Hernia

The potential occurrence of metachronous hernia is a subject that continues to raise contention in the urologic literature. A review of 918 patients who had undergone contralateral exploration of an asymptomatic side noted a 57% rate of patency of the processus vaginalis. When age is a consideration, infants aged less than 2 months had a 63% patency rate.

However, it is also understood that postnatal obliteration of the processus vaginalis contributes to a decreased prevalence of patency with increasing age. Rowe and colleagues found that the processus vaginalis will spontaneously close in 40% of children within a few months of birth and in 60% of children by 2 years of age. The incidence of a contralateral patent processus vaginalis must be reconciled with the true incidence rate of metachronous symptomatic hernia.

Although some might advocate for immediate surgery to prevent possible incarceration and the need for an operation in the future, others contest that exploration poses an unnecessary risk to the contralateral groin. Ron and colleagues noted that 10 explorations would have to be performed to prevent 1 metachronous patent processus vaginalis. In a review of 904 unilateral hernia repairs, Given and colleagues noted only a 5.6% incidence of contralateral hernia. This finding is supported by a review of the literature performed by Nataraja and colleagues in which they found that the overall risk of a metachronous hernia seems to be 5.76%.

To avoid exploration of the contralateral side, surgeons have used ultrasonography, diagnostic laparoscopy, and insufflation of the abdomen. The Goldstein method exploits the access to the intraperitoneum at the time of ipsilateral hernia repair. Simple insufflation of the intraperitoneal space via the hernia sac allows visual confirmation of patency of the contralateral processus vaginalis. Diagnostic laparoscopy has been hailed as highly accurate and sensitive. A recent meta-analysis noted a 99.4% sensitivity and 99.5% specificity ; however, it constitutes a necessary expense related to the surgical equipment. Some have found ultrasound to be useful in the evaluation of the opposite groin. Chen and colleagues found ultrasound to be 97.9% accurate in assessing patency of the processus vaginalis when they used the criteria of a 4-mm widening of the internal ring. However, this practice is not commonly performed.

Clinical Evaluation

An adequate history is imperative to not only establish the diagnosis but to determine the acuity of presentation. Parents may report a bulge in the groin, scrotum, or labia. It may be waxing and waning in nature with crying or straining. The inability to reduce the contents in association with pain, nausea, or vomiting is a significant finding and may require prompt surgical attention. However, typical presentation is that of a boy with painless enlargement of the scrotum or groin.

Thorough physical examination is an essential component of accurate clinical assessment of a child with a hernia. It is important to examine the child in both standing and supine positions. Hernias may be reducible, irreducible, or strangulated. Spontaneous closure will not occur in grossly apparent hernias, which necessitates referral for surgical repair.

Adequate history and physical examination should supplant radiographic evaluation; however, ultrasound may be used in cases of clinical uncertainty. If there is suspicion of a torsion of gonadal structures, evaluation by a urologist or pediatric surgeon should be sought immediately.

Indications for Treatment

The consequences of delayed presentation are incarceration and strangulation. A single surgeon review of more than 6000 cases observed a 12% incidence of incarceration at a mean age of 1.5 years. The risk of incarceration is more pronounced in premature infants, thus requiring definitive surgical planning. A study from Libya evaluated the impact of delayed surgical repair after the reduction of incarcerated inguinal hernias in a pediatric population when circumstances precluded immediate repair. Gahukamble and colleagues reported a similar overall complication rate for those undergoing immediate (within 72 hours) and delayed (within 1 to 3 months) repair. However, the repeat incarceration rate was nearly 16% in those with delayed management. Fortunately, improvements in pediatric anesthesia have rendered operative mortality to nil even in the setting of emergency surgery.

Treatment

The aim of surgery is to obliterate the conduit between the peritoneal cavity and groin. Because the pathophysiology of hydrocele and hernia is similar in the infant and child, they are both generally approached from the groin rather than the scrotum or labia. Ligation of the processus vaginalis at the level of the internal inguinal ring will provide adequate repair in most cases.

Although clinically apparent hernias and many communicating hydroceles necessitate surgical intervention, simple hydroceles are only generally repaired if they have not resolved by 2 years of age or if they are associated with discomfort, secondary inflammation, or parental desire.

The literature reports a 1.2% to 3.8% recurrence rate, with more than half occurring within the first year of initial surgical repair. Risk for recurrence is related to the setting of increased abdominal pressure and the presence of an incarcerated hernia, which may complicate the repair because of tissue edema. Grosfeld and colleagues reported a 12% recurrence rate of hernias in children with ventriculoperitoneal shunts. The population of children with reasons for elevated intra-abdominal pressures, such as shunts, ascites, and peritoneal dialysis, require special attention in the postoperative course.

Recommendations

The ability to differentiate between operative and nonoperative interventions is imperative in the evaluation of the acute and subacute groin/scrotum. Motives for referral include grossly apparent hernia, the history or incident of incarceration of hernia contents, and those in whom diagnosis is in question. Risk of hernia is highest in boys, children who are premature, or in the setting of increased intra-abdominal pressure. Noncommunicating hydrocele will typically resolve before 1 year of age. Referral for hydrocele should occur in the instance of nonresolution after 1 year or in the circumstances of communicating hydrocele or inflammatory features.