Inguinal Hernia

An inguinal hernia is protrusion of preperitoneal fat, peritoneal sac or abdominal contents through the inguinal region above the inguinal ligament.

It is classified anatomically as:

• Indirect: enters through the deep inguinal ring lateral to the inferior epigastric vessels.
• Direct: protrudes through the posterior wall of the inguinal canal medial to the inferior epigastric vessels.

The distinction is anatomically important but usually does not alter the principle of elective mesh repair.

The major complications are acute irreducibility, bowel obstruction and strangulation.

Typical presentation is a groin swelling that increases with standing, coughing or straining and reduces when supine or with gentle pressure.

Pain is usually a dragging or aching discomfort rather than severe pain.

Examine standing and supine. Assess:

• Site relative to the pubic tubercle and inguinal ligament
• Reducibility
• Cough impulse
• Extension into the scrotum
• Contralateral groin
• Features of bowel obstruction or strangulation

An acutely painful irreducible hernia with vomiting, abdominal distension, focal tenderness, overlying skin change or systemic toxicity should be considered strangulated until proven otherwise.

Diagnosis is usually clinical.

Ultrasound: useful when examination is equivocal or an occult groin hernia is suspected.

CT or MRI: reserve for persistent diagnostic uncertainty, recurrent disease, complex anatomy or an alternative groin pathology.

Routine imaging is unnecessary for an obvious uncomplicated inguinal hernia.

Repair symptomatic inguinal hernias when the patient is fit for surgery.

Watchful waiting is reasonable in men with an asymptomatic or minimally symptomatic reducible hernia. The risk of an acute event is low, but symptoms frequently progress. Long term data show approximately 71% ultimately undergo repair by 10 years, predominantly because of increasing pain.

Elective repair should usually use a flat synthetic mesh.

The major options are:

• Lichtenstein repair: open anterior tension free mesh repair.
• TEP repair: totally extraperitoneal placement of mesh in the preperitoneal space.
• TAPP repair: transabdominal access followed by preperitoneal mesh placement.

TEP and TAPP provide similar effective repairs when performed by experienced surgeons. Minimally invasive repair is particularly useful for bilateral hernias, recurrent hernia after previous anterior repair and women because the entire myopectineal orifice, including the femoral canal, is visualised.

For recurrence after previous anterior repair, use a posterior preperitoneal approach where possible. For recurrence after previous posterior repair, an anterior approach avoids operating through the same scarred plane.

Mesh plugs should not be used routinely.

Acute irreducibility without evidence of strangulation may undergo gentle manual reduction with adequate analgesia and sedation. Observe after successful reduction and arrange definitive repair. Do not attempt forceful reduction when strangulation is suspected.

Failure of reduction or suspected strangulation requires emergency surgery.

At emergency operation, assess bowel viability before completing the repair. Nonviable bowel requires resection. A macroporous synthetic mesh can still be considered when bowel resection occurs without gross enteric contamination. Gross faecal contamination or established infection requires a more cautious individualised approach to prosthetic material.