Parastomal Hernia

A parastomal hernia is an incisional hernia adjacent to a stoma in which abdominal contents protrude through the abdominal wall aperture created for the stoma.

It is particularly common around end colostomies and becomes more frequent with increasing duration after stoma formation.

Risk factors include obesity, increasing age, poor tissue quality, chronic raised intra abdominal pressure and an excessively large fascial trephine.

The clinical problem ranges from an asymptomatic bulge to appliance failure, recurrent obstruction or strangulation.

Typical findings include:

• Bulging around the stoma on standing or straining
• Discomfort or dragging pain
• Difficulty fitting the stoma appliance
• Leakage and recurrent peristomal skin irritation
• Difficulty irrigating or evacuating the stoma
• Intermittent obstructive symptoms

A sudden painful irreducible parastomal swelling with vomiting, reduced stoma output or systemic deterioration suggests incarceration or strangulation.

Always examine the stoma itself for prolapse, retraction, stenosis and skin disease because these may coexist and influence reconstruction.

Diagnosis is usually clinical.

CT abdomen and pelvis: useful when anatomy is uncertain, obstruction is suspected or operative reconstruction is being planned; define the defect, hernia contents and any additional midline incisional hernia.

An asymptomatic or minimally symptomatic reducible parastomal hernia does not automatically require surgery. Use an appropriately fitted appliance, specialist stoma care and supportive garments where useful.

Elective repair becomes appropriate with significant pain, recurrent appliance problems, progressive functional impairment, recurrent obstruction or unacceptable enlargement.

Emergency repair is required for strangulation, bowel ischaemia, perforation or obstruction that cannot be resolved safely without operation.

Simple suture repair should generally be avoided in elective disease because recurrence is high. Mesh reinforcement is preferred.

Stoma relocation can move the problem rather than eliminate it and creates another abdominal wall defect. It is usually reserved for situations where local repair is unsuitable, the stoma itself must be revised or reconstruction requires a different site.

Common mesh configurations include the modified Sugarbaker and keyhole techniques.

In the Sugarbaker repair, the bowel is lateralised beneath a broad mesh so that intra abdominal pressure helps maintain coverage of the stoma aperture.

In keyhole repair, the bowel passes through a central opening in the mesh.

Pooled observational data generally show lower recurrence with Sugarbaker repair, although modern comparative data and a randomised retromuscular trial have not demonstrated consistent superiority at two years. Technique should therefore be selected according to anatomy, operative plane, previous mesh and surgeon expertise rather than treating one configuration as universally superior.

Aim to close the fascial defect where feasible rather than leaving an unnecessary large aperture underneath the mesh.

If bowel is strangulated, first address bowel viability. Permanent synthetic mesh is acceptable in a clean field and can be considered in selected clean contaminated operations without gross enteric spillage. Gross contamination or established infection substantially changes the prosthetic strategy.