Paediatric inguinal hernia

Indirect inguinal hernias are very common in boys. Direct may also be seen rarely in preterm infants or those with neurologic/spinal conditions.

Aetiology

• Arises from persistence of processus vaginalis/failure of this structure to fuse and obliterate the entrance of the canal.
  • If it only contains fluid, it is known as hydrocoele
  • If the processus remains open it is a communicating hydrocoele
  • If the processus has been obliterated proximally, it is a non-communicating hydrocoele
• It CAN also occur in girls but less common - they can still get herniation down to level of labia majora and can technically get a hydrocoele.

Risk factors

• Boys: girls 9:1
• Premature
• Anterior abdo wall defects
• Conditions with increased ascites

Presentation

• Mostly asymptomatic
• Sometimes have to rely on the word of parents/paediatrician - get them to take a photo
• Incarceration
  • Surgical emergency - both bowel and testis may become ischaemic
  • Highest risk in newborns and first 2 years
• Examination
  • Should be able to differentiate hydrocoele and hernia as follows
    • If reducible - it's a reducible inguinal hernia
    • If irreducible and non-tender it's a hydrocoele
    • If irreducible and tender it's an incarcerated hernia
    • Should also be able to get above a hydrocoele and feel a normal spermatic cord
    • Hydrocoeles should be transillumable
    • USS can settle any ambiguities
  • Make sure it's not a femoral hernia - these are possible, especially between 5-10yo girls who have a lump inferior to inguinal ligament - need to be repaired urgently

Treatment

• Most hydrocoeles will undergo spontaneous involution by 1 year old
  • As long as it doesn't change in size, these can be observed
  • Communicating hydrocoele should be repaired electively if it hasn't closed by then
• All other inguinoscrotal abnormalities should be repaired
• Incarcerated
  • Resuscitate
  • Attempt to reduce - appropriate to be aggressive to prevent testicular ischaemia. Multiple attempts and use of sedation may be necessary. Mostly can be reduced.
  • Surgical repair is very difficult - thin and oedematous sac, and risk of damage to cord structures is high. Should be done by paeds surg.
  • Herniotomy is the treatment of choice rather than herniorraphy
  • If an incarcerated hernia is reduced, repair should be done within the next two days

Herniotomy: (from Kirk's)

• 2cm incision in a skin crease, midway between the deep ring and pubic tubercle
• Clear a small patch of EO about 1cm above the inguinal ligament
• Incise EO, but not as far as the external ring
• Find the cord (the ilioinguinal nerve is a useful landmark, because the cord lies between the nerve and the inguinal ligament) and open cremaster muscle, separating the cord from cremaster circumferentially
• Split internal spermatic fascia longitudinally and gently sweep vas and vessels away from the sac
• Ensure the sac is empty, perhaps by opening it, clamp it and divide distal to the clamp, allowing the distal part of the sac to fall away
• Dissect the outside of the sac back to the inferior epigastric vessels
• Suture transfix the sac
• Close the inguinal canal and re-approximate Scarpa's
• Check testis is back in scrotum