FRCA Notes

Herniorrhaphy

The curriculum asks us to manage 'common anaesthetic problems in the neonatal period and explain their perioperative anaesthetic management e.g. inguinal hernia'.

The topic was the subject of an SAQ in 2017, with marks available for perioperative concerns (~50%), options for anaesthesia (~25%) and the advantages/disadvantages of GA (~25%).

Resources

  • Most inguinal hernias in infancy are indirect; a consequence of bowel herniation through the deep inguinal ring in the presence of a widely patent processus vaginalis
    • The processus vaginalis in boys usually closes spontaneously in the first 2 months of life, and certainly by 2yrs
    • In girls the corresponding protrusion (diverticulum of Nuck) closes at 7 months
  • Overall incidence 0.74% (females) to 6.6% (males)
  • Highest incidence in the first year of life
    • Neonatal incidence 1-5%
    • Premature infants have an increased risk of 11%
    • Extremely low birth weight (<1kg) infants the rate is 40%

  • 60% are right-sided, 30% left
  • 10% are bilateral, and this is a more common occurrence in premature or low birth weight infants
  • Rates of incarceration are higher in premature infants

Risk Factors

  • Male
  • Prematurity
  • Low birth weight
  • Associations
    • Urological abnormalities: hypospadias, cryptorchidism, bladder extrophy
    • Raised intra-abdominal pressure e.g. ascites, VP shunt, peritoneal dialysis
    • Abdominal wall defects i.e. exomphalos, gastroschisis
    • CF
    • Mucopolysaccharidoses
    • Connective tissue disorders: Ehlers-Danlos syndrome, Marfan syndrome
  • Family history

  • Painless, intermittent groin swelling
  • Swelling may be associated with straining
  • May have a reducible groin mass
  • Non-reducible hernia with symptoms of bowel obstruction or bowel perforation

  • Definitive management is surgical repair by reduction of the hernia, closure of the patent processus vaginalis and repair of the floor of the inguinal canal
  • Timing of the surgery depends on a balance between infant development, presence of other comorbidities and risk of bowel incarceration/strangulation
  • Asymptomatic hernias may be repaired electively, although is at risk of incarceration prior to repair
  • Symptomatic hernias may be manually reduced first, then surgically repaired after a delay to allow swelling to subside, or surgically repaired immediately if manual reduction is unsuccessful
  • Surgical approach may be open or laparoscopic; the latter is associated with:
    • Better anatomical visualisation and ability to repair the contralateral side
    • Better cosmesis
    • Reduced LOS
    • Improved post-operative pain scores

Perioperative management of the child undergoing inguinal hernia repair


  • The main perioperative concerns arise from:
    1. Potential requirement for neonatal anaesthesia
    2. Potential management of the patient with prematurity, and its associated risks
    3. Potentially managing a patient with bowel obstruction and/or strangulation
  • The choice of technique is made on a case-by-case basis, taking into account surgical and patient factors

General Anaesthesia

  • Often combined with a regional technique e.g. caudal, ilioinguinal block
  • SAD and ETT techniques are described
  • Short-acting drugs are preferable to reduce risk of post-operative apnoes e.g. desflurane/sevoflurane, short-acting opioids
Advantages Disadvantages
Secure airway ↑ risk of apnoea vs. RA
No time limit on surgery May require post-op. respiratory support
Familiar ↑ systemic analgesia requirements

Regional anaesthesia

  • Options include spinal, epidural or caudal anaesthesia
Advantages Disadvantages
Avoids airway instrumentation Technically difficult with 10 - 20% failure rate
↓ risk of apnoeas/bradycardia Does not eliminate risk of apnoea
Avoids GA if comorbidities present May require sedation or conversion to GA anyway
↓ use of systemic analgesics Limits time available for surgery
Adjuvant drugs can prolong block No muscle relaxation
↓ PACU recovery time Not suitable for laparoscopy


  • Risk factors for prolonged PACU stay include:
    • Post-menstrual age <45 weeks
    • Prematurity
    • GA technique alone i.e. without adjuvant regional anaesthetic technique
    • Use of post-operative opioids

Analgesia

  • Paracetamol at appropriate dose
  • NSAID; IV, PR and PO options

  • Local anaesthetic
    • Wound infiltration of port sites
    • Ilioinguinal block
    • TAP block
    • Paravertebral
    • Caudal

  • Short-acting opioid for breakthrough pain e.g. IV fentanyl
  • Consider tramadol or nalbuphine for rescue analgesia on the ward

Apnoea

  • Highest risk in infants, especially the ex-premature infant
  • Mostly occurs in those <44weeks post-menstrual age
  • Often resolves spontaneously but may require oxygen, ventilatory support, CPAP or even CPR
  • See pages on neonatal anaesthesia and prematurity