Incarcerated Hernia

A lumbar hernia is protrusion of retroperitoneal or intra abdominal contents through a defect in the posterolateral abdominal wall. Primary lumbar hernias usually occur through either the superior lumbar triangle or inferior lumbar triangle.

The superior lumbar triangle, or Grynfeltt Lesshaft triangle, is bounded by the twelfth rib superiorly, quadratus lumborum medially and internal oblique laterally.

The inferior lumbar triangle, or Petit triangle, is bounded by latissimus dorsi medially, external oblique laterally and the iliac crest inferiorly.

Lumbar hernias may be primary or secondary to previous flank surgery, trauma, infection or muscle denervation. The defect progressively enlarges and incarceration is sufficiently common that definitive repair is generally preferred once the diagnosis is established.

Patients usually present with a posterolateral abdominal or flank swelling that enlarges with coughing, standing or straining and may reduce when supine.

Pain is typically a dull flank discomfort or dragging sensation.

Large defects may contain retroperitoneal fat, colon or small bowel.

Acute persistent pain, irreducibility, vomiting or abdominal distension suggests incarceration or bowel obstruction. Strangulation is less common but requires immediate intervention.

Differentiate lumbar hernia from lipoma, soft tissue tumour, muscle atrophy, renal mass and postoperative flank bulge from denervation.

CT abdomen and pelvis: investigation of choice; defines the fascial defect, hernia contents, surrounding muscle anatomy and relationship to the twelfth rib and iliac crest.

Imaging is particularly important before repair because the external swelling can substantially underestimate the actual fascial defect.

Repair is appropriate for most fit patients because lumbar hernias tend to enlarge and have a meaningful risk of incarceration.

Mesh reinforcement is preferred to primary suture repair.

A minimally invasive preperitoneal or transabdominal repair is suitable for many small and moderate primary defects. The hernia contents are reduced, the defect is closed where feasible and a sufficiently large mesh is placed with broad overlap.

Open reconstruction is more appropriate for:

• Very large defects
• Previous flank surgery with dense scarring
• Significant muscle loss
• Recurrent lumbar hernia
• Defects extending to the iliac crest or rib where fixation is difficult

Large defects may require retromuscular or preperitoneal mesh with fixation to strong fascial or bony structures. Direct fixation near the twelfth rib requires care because of the subcostal neurovascular bundle.

Do not close a large defect under excessive tension simply to avoid mesh.

Acute incarceration or suspected strangulation requires urgent surgery. Assess bowel viability after reduction and resect nonviable bowel where necessary.

In a clean operative field, synthetic mesh provides durable reinforcement. Gross enteric contamination should alter the reconstruction strategy and may require temporary primary closure or delayed definitive abdominal wall repair.