Hernias

Introduction

• 10% lifetime incidence
• Incarcerated – Firm, often painful and nonreducible by direct manual pressure
• Strangulated – Impairment of blood flow
  • Severe, exquisite pain at hernia site with signs of intestinal obstruction, toxic appearance and sometimes skin changes over the hernia site
  • Acute surgical emergency

Inguinal

• 75% of all hernias occur in inguinal region
• 2/3 indirect
• Clear male predilection but inguinal hernias still the most common hernia in women
• Typically present due to mass enlargement or symptoms of incarceration or herniation
• DDx includes hidradenitis, abscess, sebaceous cyst, lymphoma, hydrocoele, varicocoele, femoral hernia or femoral aneurysm/ruptured AAA
• Bedside USS extremely useful if diagnosis is in question (100% specificity and sensitivity if trained in use)

Inguinal

• Direct inguinal hernia
  • Through Hesselbach triangle (weakness in transversalis fascia) with lateral border of inferior epigastric arteries, medial border of rectus sheath and inferior border of inguinal ligament
  • Do not pass through inguinal canal or into scrotum
  • Less often suffer incarceration/strangulation
• Indirect inguinal hernia
  • Internal to external inguinal ring via patent processus vaginalis and then to scrotum/labia majora
  • Commonly suffer incarceration (esp. in women and infants)
  • Seen in 5% of term infants and 30% of preterm infants

Paediatric hernias

• Inguinal
  • 3-4x higher in boys than girls
  • Right sided more commonly
  • Incidence peaks in first month of life in boys
  • Incarceration occurs in 15-30%, usually in infants <1yo
  • Incarceration more common in girls (typically containing ovary)
• Management
  • Prompt referral for outpatient surgical f/u if reducible/good story for mass
  • Manually reduce if no evidence of strangulation or female (with suspected incarcerated ovary)
  • Admit surgically for repair (some surgeons may delay for easier repair at later date)

Ventral and incisional hernias

• Ventral
  • Epigastric
  • Umbilical
  • Incisional
  • Hypogastric
• Incisional hernias
  • 20% of abdominal wall hernias and seen in 10-20% of patients post-laparotomy
  • Risk factors include obesity, age, wound infection, COPD
  • Recurrence rate as high as 50% despite primary repair
  • Usually wide origin so rarely incarcerate
  • Carry risks of discomfort, extrusion of abdominal contents and incarceration/strangulation

Umbilical

• Umbilical hernias
  • Largely acquired due to increased intra-abdominal pressure including ascites, obesity, pregnancy, COAD
  • Female 3x more common than males
  • Strangulation is unusual EXCEPT in chronic ascites which carries risk of strangulation, rupture and death from peritonitis
  • Usually increase in size over time and require non-urgent repair
  • In children, almost always congenital and rarely incarcerate. Self-resolve in most cases by age 5
    • May need intervention if incarceration or failure to improve over first 2 years of life

Femoral hernia

• Hernia sac protrudes through femoral canal leading to mass below the inguinal ring
• More common in women (10:1)
• Particularly prone to incarceration and strangulation
• 40% emergency surgery rate
• All should be urgently referred for repair
• Delays lead to increased rates of strangulation reaching 45% at 21 months
• 13% mortality from delayed repair and 31% complication rate

Spigelian hernia

• Aka Lateral ventral hernia
• Arises at edge of rectus muscle and arcuate line
• Due to increased abdominal pressure
• Difficult to diagnose
• Classically present as abdominal pain with anterolateral abdominal wall mass/bulge
• Bedside USS can accurately and rapidly make diagnosis
• CT scan also effective
• Should be surgically corrected as carry high risk of strangulation

Obturator hernia

• Bowel herniation through obturator canal
• Presents as either partial or complete bowel obstruction
• Usually elderly frail woman with bowel obstruction
• Howship-Romberg sign = pain in medial thigh due to obturator nerve compression
• CT scan is diagnostic
• High complication rates so MUST diagnose
  • >50% risk of perforation and mortality approaching 20%

Richter hernia

• Involves antimesenteric border of intestine only
• Often presents with vomiting or intestinal obstruction and more often leads to incarceration, strangulation and gangrene
• Surgical repair indicated once diagnosed

USS

• Insensitive for strangulation as can identify arterial flow into hernial sac but Doppler is not sensitive enough to rule out venous or lymphatic flow
• Free fluid in hernial sac is suggestive of impaired venous flow and strangulation
  • Sensitivity good but not specific enough, especially if ascites evident
• Other findings of incarceration/strangulation include:
  • Hyperechoic fat
  • Isoechoic thickening of hernial sac
  • Thickening of wall of herniated bowel
• Peristalsis presence implies bowel resection unlikely to be required on repair

CT

• Most sensitive and specific for hernia identification

Treatment

• If easily reducible – refer to elective outpatient surgical repair
• If exquisitely tender or systemic signs then assume strangulation and consult surgery immediately
• Broad-spec AB’s, fluid resuscitation, narcotic analgesia and preop labs
• If incarcerated but not strangulated clinically, make one or two attempts at reduction in ED
  • NBM
  • Adequate narcotic analgesia +- nitrous oxide
  • Cold packs to hernia site
  • Grasp and elongate hernia neck with one hand and with other apply firm steady pressure to proximal part of hernia at neck at side of fascial defect
  • Applying pressure at distal part of hernial sac causes ballooning and prevents reduction
  • Consult surgery if failed after 1-2 attempts

Treatment

• If reduced in ED, observe with serial abdo examinations for several hours
• Persistent significant abdominal pain suggests reduction en mass (incarcerated hernia reduced back into peritoneal cavity but loop of bowel remains inside hernia sac after reduction, so that retained bowel remains incarcerated)
  • Imaging can detect this uncommon but serious diagnosis
• If any concern of strangulation, do not attempt reduction
  • Re-introduction of ischaemic, necrotic bowel back into the peritoneal cavity can result in perforation and sepsis

Last Updated on October 28, 2020 by Andrew Crofton