Incisional

• Incisional hernias are a diverse group of conditions ranging from tiny port site hernias to total abdominal wall failure. They will complicate around 15% of all abdominal operations and have become increasingly common as more and more patients are undergoing surgery at some point in their lives.
• An incisional hernia is a ventral hernia characterised by the protrusion of intra-abdominal contents through the site of a previous surgical incision.
• Anatomy:

  • Midline laparotomy through the linea alba is the most frequently used abdominal incision
  • There is only one fascial layer - thinnest part of the abdominal wall
  • Therefore incisional hernias most commonly occur in the midline
• Laparoscopic surgery:

  • Multiple small incisions (port sites)
  • A fascial defect 1cm in size can still cause a hernia if not closed properly
  • Port site hernias have a high risk of obstruction or strangulation
• Parastomal hernia:

  • Incisional hernia related to a stoma site
  • Stoma formation involves the creation of a tunnel through the rectus sheath and rectus abdominis muscle to bring the bowel out onto the skin
  • This leaves a residual fascial defect which often allows other intra-abdominal contents to escape over time
  • More likely to occur with a colostomy
• Incisional hernias occur because the fascial closure of the abdominal wall failed to heal properly. Wound healing depends upon the direct approximation of healthy tissue edges with minimal tension, no contamination or infection, a good blood supply, and adequate nutrition. 
• Technical risk factors:

  • Suboptimal fascial closure
• Patient risk factors:

  • Raised intra-abdominal pressure: obesity, coughing, vomiting or post-operative ileus
  • Impaired blood supply: smoking, peripheral arterial disease, diabetes and radiotherapy
  • Malnutrition from chronic illnesses (inadequate protein): kidney disease, liver disease and intestinal disorders
  • Corticosteroids, immunosuppressants and chemotherapy increase the risk of infection and also dampen the inflammatory response to injury
• Clinical features:

  • Mostly asymptomatic - lump that has gradually increased in size since surgery
  • Incisional hernias tend to be more painful than primary hernias
  • Large hernias can be functionally debilitating as they impair the patients core muscle strength and stability
  • Up to 15% present acutely with obstruction or strangulation
  • Palpable lump close to a previous surgical scar or stoma - may be difficult to feel due to scarring
• Imaging:

  • Ultrasound can help diagnose small defects such as port site hernias
  • Larger hernias and those associated with open incisions should be investigated with a CT scan to facilitate surgical planning
• Management:

  • Asymptomatic - conservative management
  • Symptomatic - open or laparoscopic mesh repair
  • Symptomatic parastomal - reverse the stoma, performing a mesh repair around the stoma, or moving the stoma to another site
  • Repair can be technically challenging as many patients will have scarring and tissue damage from previous surgery