Obturator Hernia

An obturator hernia is protrusion of intra abdominal contents through the obturator canal alongside the obturator neurovascular bundle.

It is rare but clinically important because diagnosis is often delayed until small bowel obstruction or strangulation develops.

The typical patient is an older, thin woman, particularly after multiple pregnancies or significant loss of preperitoneal fat.

The hernia neck is narrow and rigid, giving it a high risk of bowel compromise.

Most patients present with features of small bowel obstruction rather than an obvious groin mass.

There may be abdominal pain, vomiting, distension and constipation.

Howship Romberg sign: pain along the medial thigh caused by compression of the obturator nerve, often extending toward the knee and worsened by hip extension, abduction or internal rotation.

Hannington Kiff sign: absent thigh adductor reflex with a preserved patellar reflex.

Neither sign is sufficiently sensitive to exclude the diagnosis when absent.

A palpable groin mass is usually absent.

Maintain a high index of suspicion in an older thin woman with unexplained small bowel obstruction and no previous abdominal surgery.

CT abdomen and pelvis with IV contrast: diagnostic test of choice; demonstrates bowel entering the obturator canal and assesses obstruction and bowel viability.

Do not delay surgery when CT demonstrates strangulated bowel or when peritonitis develops.

Obturator hernia requires operative repair.

Begin bowel obstruction resuscitation with fasting, IV crystalloid, electrolyte correction and nasogastric decompression when vomiting or significant distension is present.

If strangulation or bowel necrosis is suspected, give enteric Gram negative and anaerobic coverage, for example:

Ceftriaxone 2 g IV every 24 hours plus metronidazole 500 mg IV every 12 hours.

Proceed urgently to surgery.

Laparoscopic repair is appropriate in a haemodynamically stable patient when expertise is available because it permits evaluation of both obturator canals and direct assessment of bowel viability.

Laparotomy remains appropriate with major bowel distension, uncertain anatomy, peritonitis, haemodynamic instability or when bowel resection is anticipated.

After reduction, allow questionable bowel to reperfuse before deciding viability. Resect clearly necrotic bowel.

The obturator defect can be closed with sutures or mesh. Mesh provides a broad durable repair in a clean operative field. Published series show increasing use of laparoscopic mesh repair with low reported recurrence.

When bowel perforation or gross contamination is present, avoid placing permanent synthetic mesh directly into a heavily contaminated operative field and choose primary closure or delayed reconstruction according to defect size and tissue quality.