• Increased intra-abdominal pressure (e.g. straining or lifting)
• Abdominal weakness (e.g. advancing age or malnutrition)

Clinical features

• Hernia usually present with a lump at an appropriate anatomical site
• The hernia often increases in size on coughing or straining
• It reduces in size or disappears when relaxed or supine
• Examination may show it to have a cough impulse and to be reducible
• Irreducible but non-obstructed hernias may cause little pain
• If the hernia causes obstruction colicky abdominal pain, distension and vomiting may occur
• The hernia will be tense tender and irreducible
• If strangulation occurs the lump will become red and tender
• Diagnosis is usually based on clinical features
• Herniography may be useful in the investigation of chronic groin pain
• Ultrasound or CT may be useful if a clinically occult hernia is suspected

< 60 yrs	0.1%
60 - 69 yrs	0.2%
70 - 79 yrs	1.6%
>80 yrs	3.3%

Mortality of strangulated hernia repair

• 10% patients with strangulation give no previous history of a hernia
• The peak incidence of hernia strangulation is approximately 80 years
• In those with acute onset of a hernia the greatest risk is in the first 3 months
• Risk of strangulation depends on type of hernia
  • Femoral is approximately 40%
  • Direct inguinal is approximately 3%
• The mortality of surgery for strangulated hernias has changed little over the past 50 years
• Operative mortality remains at approximately 10%
• Is ten times greater than that following an elective repair
• Risk of death is dependent on:
• Age
• Presence of necrotic bowel requiring resection

Inguinal hernias

• 80,000 operations per year in UK
• 3% adults will require operation for inguinal hernia
• Male : female ratio is 12:1
• Elective : emergency operation 12:1
• Peak incidence is in the 6th decade
• 65% inguinal hernias are indirect
• In females inguinal hernias are as common as femoral hernias

Anatomy

• Inguinal canal lies between the superficial and deep inguinal rings
• Deep ring lies deep to the mid-inguinal point
• Mid-inguinal point is half way between symphysis pubis and anterior superior iliac spine
• Not the midpoint of the inguinal ligament
• In men it contains vas deferens and testicular artery and veins
• In women it contains the round ligament
• Anterior border is the external oblique aponeurosis
• Posterior border is the transversalis fascia
• Inferior border is the inguinal ligament
• Superior border is the conjoint tendon - the lower fibres of internal oblique and transversus abdominis
• Indirect hernias arise lateral to the inferior epigastric vessels
• Direct hernias arise medial to the inferior epigastric vessels

Classification of inguinal hernias (Nyhus)

Type 1	Indirect hernia with normal internal ring
Type 2	Indirect hernia with dilated internal ring. Posterior wall intact
Type 3	Posterior wall defect
A	Direct inguinal hernia
B	Indirect inguinal hernia. Internal ring dilated. Posterior wall defective
C	Femoral hernia
Type 4	Recurrent hernia

Techniques of inguinal hernia repair

• Herniotomy involves removal of the sac and closure of the neck
• Herniorrhaphy involves a form of reconstruction to
  • Restore the disturbed anatomy
  • Increase the strength of the abdominal wall
  • Construct a barrier to recurrence
• Herniorrhaphy can be achieved with following techniques
  • Bassini +/- Tanner Slide
  • Darn
  • Shouldice
  • Lichtenstein
  • Other Mesh - Stoppa
  • Laparoscopic
• Shouldice or Liechtenstein now regarded as 'gold standard' as judged by low risk of recurrence
• Laparoscopic hernia repair should be reserved for bilateral or recurrent hernia

Complications of hernia repairs

• Urinary retention
• Scrotal haematoma
• Damage to the ileoinguinal nerve
• Ischaemic orchitis
• Recurrent hernia

Trusses

• 40,000 sold annually in UK
• 20% purchased prior to seeing a doctor
• 45% have no instruction on fitting
• 75% fit whilst standing up!

Recurrent inguinal hernia

• Recurrence rate varies with herniorrhaphy technique and duration of follow up
• With Bassini and darn repairs may be as high as 20%
• With Shouldice and Lichtenstein repairs recurrence rates <1% have been reported
• Factor involved in recurrence include:
  • Inadequate preoperative selection
  • Type of hernia
  • Type of operation
  • Postoperative wound infection
• Recurrent hernias should be repaired using a mesh technique
• Can be performed as either an open or a laparoscopic procedure
• Patients should be consented for a possible orchidectomy

Femoral hernias

• Account for 7% of all abdominal wall hernia
• Female : male ratio is 4:1
• Commonest in middle aged and elderly women
• Rare in children
• More common in parous
• Much less common than inguinal hernias but are as common as inguinal hernias in older women

Anatomy of the femoral canal

• Anterior border is the inguinal ligament
• Posterior border is the pectineal ligament
• Medial border is the lacunar ligament
• Lateral border is the femoral vein

Differentiation between inguinal and femoral hernias

Inguinal hernia	Femoral hernia
Femoral hernia	Inguinal hernia
Vaginal hydrocele	Lymphadenopathy
Hydrocele of the cord	Saphena varix
Undescended testis	Ectopic testis
Lipoma of the cord	Psoas abscess
	Psoas bursa
	Lipoma

Management of femoral hernia

• All uncomplicated femoral hernias should be repaired as an urgent elective procedure
• Three classical approaches to the femoral canal have been described
  • Low (Lockwood)
  • Transinguinal (Lotheissen)
  • High (McEvedy)
• Irrespective of approach used the following will be achieved
  • Dissection of the sac
  • Reduction / inspection of the contents
  • Ligation of the sac
  • Approximation of the inguinal and pectineal ligaments

Special types of hernia

• Richter's hernia
  • Partial enterocele
  • presents with strangulation and obstruction
• Maydl's hernia
  • W loop strangulation
  • Strangulated bowel within abdominal cavity
• Littre's hernia
  • Strangulated Meckel's diverticulum
  • Can cause small bowel fistula