Inguinal hernia is a protrusion of abdominal contents (intestine, omentum) into, and often through, the inguinal canal.
- Inguinal hernia is the most frequent problem requiring elective surgical intervention in children.
- Significantly more common in boys (90% of cases)
- Has a familial tendency
- Because of later descent of right testis and subsequently delayed obliteration of right processus vaginalis, inguinal hernia presents more frequently on the right side.
- Clinical presentation is on the right side in 60% of cases, on the left side in 30%, and bilateral in 10%.
- Frequency varies with age and ranges from 3–5% in full-term babies to 10–30% in preterm infants.
- Urologic conditions: cryptorchidism, hypospadias, epispadias, bladder exstrophy
- Abdominal wall defects: gastroschisis, omphalocele, Eagle-Barrett syndrome
- Conditions that increase intra-abdominal pressure (e.g., ascites, peritoneal dialysis, ventriculoperitoneal shunt)
- Cystic fibrosis
- Connective tissue disease: Marfan syndrome, Ehlers-Danlos syndrome
- Family history
Indirect inguinal hernia
- During the 7th month of male gestation, the testes begin their descent from the peritoneal cavity through the inguinal canal into the scrotum.
- Between the 7th and 9th months of gestation, after the testes reach the scrotum, the path of peritoneum through which the testicle passed (processus vaginalis) begins to obliterate spontaneously, leaving only a small potential space adjacent to the testes (tunica vaginalis).
- In girls, although the ovaries do not leave the abdomen, the round ligament (part of the gubernaculum) travels through the inguinal ring into labium majus. When the processus vaginalis remains open, it is called the canal of Nuck.
- Incomplete obliteration of the processus vaginalis leaves a sac of peritoneum extending all the way from the internal inguinal ring to the scrotum or labium majus, through which an inguinal hernia may develop.
Direct inguinal hernia
- Uncommon in children
- Results from either a congenital or acquired/traumatic weakness or tear in abdominal wall fascia
Other types of inguinal hernias
- Sliding hernia occurs when one wall of the hernia is composed of abdominal viscera (bladder, colon, adnexa).
- Richter hernia results from the herniation of only a part of the bowel wall. If this hernia is incarcerated/strangulated, it may progress to bowel perforation without obstruction.
- Hernia of Littre includes a Meckel diverticulum within the hernia sac.
- Amyand hernia is an inguinal hernia in which the appendix is included within the hernia sac.
- Most common presentation is complaint of swelling or bulge in the inguinal area.
- Intermittently appearing
- Present during times of increased intra-abdominal pressure such as crying or straining
- A picture taken by the caregiver while the hernia is out may be helpful.
- Reducible hernias are not generally painful.
- If bulge is painful, incarcerated inguinal hernia must be suspected, and other etiologies (e.g., testicular torsion) should be excluded.
- Examine the child in the supine and upright positions.
- If the bulge is apparent in the standing position but disappears when the child is supine, presence of a hernia is strongly suggested.
- Reduction of hernia contents through the inguinal ring is confirmatory.
- If the bulge is not readily apparent, perform maneuvers that increase intra-abdominal pressure (gently press on his or her abdomen, have him or her cough, or strain or jump around).
- Can be an unreliable finding, particularly in babies
- Some inguinal hernias (which usually do not transilluminate) can be differentiated from hydroceles (which usually do transilluminate).
- Silk glove sign
- When empty hernia sac is palpated over the cord structures, sensation is similar to rubbing 2 layers of silk together: thick tissue that slides over cord structures
- Tender scrotal mass: Consider incarcerated hernia, testicular torsion, epididymitis, orchitis, or trauma.
Diagnostic Tests and Interpretation
- In cases where incarceration is suspected, such as presentation with a hard, painful, swelling in the groin, CBC and chemistry should be checked. Leukocytosis or acidosis should increase concern for compromised bowel.
- Genetic testing
- Karyotype is necessary when a testis is discovered during hernia repair in a phenotypic female. Biopsy of the gonad is also typically performed.
- 1% of full-term females with bilateral inguinal hernias have a disorder of sexual development—complete androgen insensitivity.
Diagnosis is usually made with history and physical exam. However, use of scrotal or inguinal ultrasonography is indicated in cases involving:
- Scrotal tenderness
- Suggestion of torsion (use duplex ultrasound to evaluate blood flow)
- Scrotal trauma and concern for testicular rupture
- Mass along the spermatic cord or testicular tumor
- Retractile testis
- Undescended testis
- Testicular tumor
- Try to reduce the hernia with the child in the supine and/or head-down position so that gravity assists the maneuver.
- Many suggest application of pressure to hernia that is directed toward the inguinal canal.
- Gentle traction of the sac away from the canal and toward the contralateral knee is sometimes more effective if constant pressure is applied to the hernia sac contents.
- The neck of the hernia is elongated by the traction and placed in line with the inguinal canal.
- As edema is squeezed out, contents slip back into the abdomen.
- It is typical to feel a “pop” at the internal ring once the hernia is completely reduced. This can lead to immediate relief of symptoms.
Inguinal hernia will not resolve spontaneously and must be treated surgically to avoid incarceration.
- Complication rate after elective inguinal hernia repair is low (1–2%).
- Hernia incarceration commonly occurs in the 1st year of life and is associated with markedly increased complication rate at repair (20%). To avoid this risk, repair is recommended soon after diagnosis of an inguinal hernia.
- Surgeons will often wait 24–48 hours after reduction of an incarcerated hernia to operate in order to allow edema to resolve.
- Routine contralateral inguinal exploration in children with unilateral hernia continues to be a topic of debate. Some surgeons perform diagnostic laparoscopy to evaluate for a contralateral patent processus vaginalis at the time of unilateral herniorrhaphy.
- Laparoscopic inguinal hernia repair can be performed safely in children of all ages, with a variety of techniques.
There is no consensus regarding the optimal timing for hernia repair in hospitalized infants. The risk of incarceration must be balanced against the potential risks of operative and anesthetic complications.
- Preoperative: Parents should consult a physician immediately if signs of incarceration are present (firm or tender lump, pain, or emesis).
- Postoperative: Avoidance of major physical activity for 1 week is recommended.
- Incarceration: >50% of cases occur within the first 6 months of life.
- Bowel obstruction secondary to incarcerated loop of small intestine
- Strangulation: incarceration with progression to ischemia
- Intestinal infarction can lead to perforation and peritonitis.
- Testicular/ovarian ischemia or infarction. Ovaries are less likely to suffer ischemic insult given narrow vascular pedicle.
- Sarpel U, Palmer SK, Dolgin SE. The incidence of complete androgen insensitivity in girls with inguinal hernias and assessment of screening by vaginal length measurement. J Pediatr Surg. 2005;40(1):133–136. [PMID:15868573]
- Wang KS; Committee on Fetus and Newborn, American Academy of Pediatrics; Section on Surgery, American Academy of Pediatrics. Assessment and management of inguinal hernias in infants. Pediatrics. 2012;130(4):768–773. [PMID:23008462]
- Yang C, Zhang H, Pu J, et al. Laparoscopic vs open herniorrhaphy in the management of pediatric inguinal hernia: a systemic review and meta-analysis. J Pediatr Surg. 2011;46(9):1824–1834. [PMID:21929997]
- 550.90 Inguinal hernia, without mention of obstruction or gangrene, unilateral or unspecified (not specified as recurrent)
- 550.10 Inguinal hernia, with obstruction, without mention of gangrene, unilateral or unspecified (not specified as recurrent)
- 550.12 Inguinal hernia, with obstruction, without mention of gangrene, bilateral (not specified as recurrent)
- K40.90 Unil inguinal hernia, w/o obst or gangr, not spcf as recur
- K40.20 Bi inguinal hernia, w/o obst or gangrene, not spcf as recur
- K40.30 Unil inguinal hernia, w obst, w/o gangr, not spcf as recur
- 396232000 inguinal hernia (disorder)
- 85502002 Bilateral inguinal hernia (disorder)
- 65626001 indirect inguinal hernia (disorder)
- 73147001 direct inguinal hernia (disorder)
- 236022004 left inguinal hernia (disorder)
- 236021006 right inguinal hernia (disorder)
- Q: When should a pediatric surgeon be consulted for a suspected inguinal hernia?
- A: Inguinal hernias do not resolve and require repair to avoid the complications associated with incarceration and strangulation. A pediatric surgeon should be consulted at the time of diagnosis in order to plan for herniorrhaphy. Additionally, findings suspicious for incarceration or strangulation such as a painful, swollen mass in the inguinal area should result in immediate pediatric surgical consultation as urgent intervention may be required.
- Q: At what age is a patient most at risk for incarceration of an inguinal hernia?
- A: Incarceration of an inguinal hernia most often occurs within the first 6 months of life.
Nora M. Fullington
Jeremy T. Aidlen
© Wolters Kluwer Health Lippincott Williams & Wilkins
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