Hernias

 

• Background

  Definition

  • From Surgical Talk: "the protrusion of a viscus or part of a viscus through the walls of its containing cavity into an abnormal position".
  • Comprises a hernial sac and neck.

  Classification

  By presentation:

  • Reducible
  • Irreducible (incarcerated).
  • Obstructed (bowel within is obstructed).
  • Strangulated (ischaemic).

  Other classifications:

  • Sliding hernia: contains partly extraperitoneal structure (e.g. caecum or sigmoid colon), such that the hernial sac doesn't totally surround the contents (or in other words, a viscus forms part of the wall).
  • Richter's hernia: only part of the lumen protrudes. Can cause strangulation without obstruction.
  • Maydl's hernia: W-shaped loop (two adjacent loops) in hernial sac with tight, strangulated neck.

  Sites

  • Abdominal wall: inguinal, femoral, epigastric, umbilical, paraumbilical, incisional.
  • Internal: diaphragmatic (hiatus or congenital), mesenteric, omental.

  Epidemiology

  • Lifetime risk: 1/3 men, 1/30 women.
  • 75% are inguinal, 8% are femoral. Other types each account for <5%.

• Presentation

  • Usually asymptomatic or a mild discomfort/pain, which may be heavy, dragging, and/or worse on straining.
  • Strangulation presents with extreme pain and tenderness, bowel obstruction, and/or sepsis.
  • Femoral hernias are easily missed, so make sure to check the hernial orifices in any acute abdomen.

• Risk factors

  Increased intra-abdominal pressure:

  • Chronic cough, constipation, or urinary obstruction.
  • Ascites
  • Heavy lifting.

  Wall weakness:

  • Obesity
  • Smoking
  • Previous surgery.
  • Connective tissue disorders.

• Inguinal hernias

  Anatomy and epidemiology

  • Commoner in men.
  • Viscus passes through the inguinal canal – which also contains the spermatic cord – and protrudes through the superficial inguinal ring, above and medial to the pubic tubercle (PT). However, they may be felt lateral to the PT – where they enter the canal – when not fully protruded.
  • Distinction between indirect and direct hernias is difficult to reliably do through clinical examination and doesn't affect management anyway.

  Indirect hernias

  • Commonest type, affecting young as well as old.
  • Enter the inguinal canal at the deep inguinal ring.
  • May be congenital, due to patent processus vaginalis. Should be repaired early.

  Direct inguinal hernias

  • Protrude through the abdominal wall into the inguinal canal, medial to the inferior epigastric artery.
  • Usually affect elderly only.
  • Less prone to complications.
  • Unlike indirect hernias, they rarely extend into scrotum.

  Inguinal canal borders

  • Anterior: external oblique aponeurosis.
  • Floor: inguinal ligament, which is the lower edge of the external oblique aponeurosis.
  • Posterior: transversalis fascia.
  • Roof: transversalis fascia, transversus abdominis, and internal oblique.

• Femoral hernias

  Anatomy

  • Protrusion through the femoral canal.
  • Femoral canal borders, FLIP: Femoral vein (lat), Lacunar ligament (med), Inguinal ligament (ant), Pectineal ligament (post).

  Clinical features

  • 70% occur in women. However, as femoral hernias are rare, inguinal hernias are still commoner in women than femoral hernias.
  • 1 in 3 present with strangulation or bowel obstruction.

• DDx: Groin and scrotal lumps

  Femoral and inguinal hernias, which can usually be distinguished by the following features:

  • Can't get above the lump.
  • Bowel sounds over lump.
  • Reducibility

  Groin lumps:

  • Inflammatory or infectious: lymph nodes, abscess.
  • Lipoma of spermatic cord.
  • Saphena varix: dilated varicose vein at sapheno-femoral junction. Reduces on lying flat.
  • Femoral artery aneurysm.

  Scrotal lumps:

  • Separate from testicle: hydrocele, varicocele (reduces on lying flat).
  • Epididymal: cyst, spermatocele, epididymo-orchitis.
  • Incompletely descended testicle.
  • Tumour

• Abdominal wall hernias

  • Epigastric hernia: small protrusion through linea alba above umbilicus, common in the young and fit.
  • Umbilical hernia: congenital defect which usually closes spontaneously by age 2. Can be due to ascites in adults.
  • Paraumbilical hernia: usually affects elderly.
  • Incisional hernia: occurs in 15% of abdominal surgery, especially midline incisions.
  • Inguinal and femoral hernias are also hernias of the abdominal wall, but present in the groin.

• Investigations

  • Most hernias are diagnosed by clinical examination.
  • Imaging, such as ultrasound, is only used if there are suggestive symptoms but no lump found e.g. hiatus hernia.
  • Strangulated hernias are investigated as an acute abdomen.

• Management

  General approach:

  • Strangulated hernias are a surgical emergency.
  • Reducible hernias are usually repaired, to prevent the risk of strangulation and reduce symptoms. The risk of strangulation in inguinal hernias is low (<1% per year), but most patients offered watchful waiting in trials eventually (<10 years) get surgery due to pain.
  • Older, asymptomatic patients not fit for surgery can be treated conservatively. A truss or abdominal binders can be used to keep the hernia reduced.

  Surgical options:

  • Mesh repair is much commoner than suture repair, and has lower post-op pain and hernia recurrence. It can be open or laparoscopic.
  • Laparoscopic repair. Pros: less post-op pain, quicker return to work (though same length of hospital stay). Cons: technically harder, more expensive, serious intra-abdominal injury (0.1%).
  • Open repair. Pros: local anaesthetic can be used (though only done in 10%).
  • Complications: recurrence (3% in 10 years), haematoma (7%), infection (1%). Similar risks with open and laparoscopic.