• An incisional hernia is a protrusion of the peritoneum (the sac) and abdominal contents into the 'subcutaneous plane through a defect at the site of a scar following an abdominal operation.

  • More than 50% occur in the first year post-operatively, and 90% occur within 3 years of surgery.

  • Following vertical midline incisions, incidence may vary between 5 to 15% at one year follow up.

  • Following laparoscopic surgery, the incidence of port site hernias is 3.6%.

  • Massive incisional herniation may occur following wound dehiscence or laparostomy (for severe abdominal sepsis or trauma) allowed to heal by secondary intention or treated by Vacuum Assisted Closure (VAC) therapy.

  • There is a higher preponderance in males.

  • Patients present electively with nagging discomfort and a bulge at the site of a previous incision, although 25% of patients may be asymptomatic.

  • Patients may present as an emergency with bowel obstruction, or incarceration with bowel ischaemia.

  • Incisional hernias increase in size with time and frequently become irreducible.

  • The main predisposing factors for an incisional hernia are poor surgical techniques, local wound complications, impaired wound healing, and increased intraabdominal pressure.

 

Clinical Assessment

  • Assess the size and shape of the defect by palpating the edges, particularly when the patient coughs or performs Valsalva manoeuvre.

  • Assess reducibility.

  • Consideration should be given to the possibility of “loss of domain” (the abdominal muscle retract so that intra-abdominal contents lie permanently outwith the margins of the abdomen).

 

Radiological Imaging

  • Radiological investigations may be useful in the assessment of small hernias in obese patients, complex hernias, or loss of domain.

  • CT is the modality of choice for assessment of large, complex or recurrent hernias.

  • Ultrasound may be used to demonstrate a fascial defect, sac contents and the size of a hernia.

  • MRI may be beneficial in the assessment of recurrent hernias to allow visualization of existing mesh and adhesions

 

Operative Management

  • Incisional hernias should be repaired because:

(i) They increase in size with time and may be very difficult to repair when large.
(ii) They are at risk of becoming irreducible, obstructed and strangulated, especially if the neck is narrow.
(iii) Patients request repair because of discomfort and unsightly appearance.
  • Operation involves defining the sac and neck, returning the contents to the abdominal cavity, and repairing the hole in the abdominal wall.

  • Available operative techniques include open mesh repair, laparoscopic mesh repair, open suture repair, and component separation techniques.

  • It is usually standard for mesh to be used due to a reduction in recurrence rates compared to simple suture repair.

  • An abdominal support or binder may be helpful in very large hernias or in patients unfit for surgery.

 

Pre-Operative Preparation

  • Preoperative weight reduction in obese patients aims to facilitate the repair, and to reduce post-operative respiratory problems and likelihood of recurrence.

  • Preoperative measures to increase volume of submuscular/subcutaneous space (e.g. tissue expanders) are rarely used.

  • Loss of domain of 20% or greater is associated with an increased risk of abdominal compartment syndrome and cardiorespiratory embarrassment post-operatively, and thus preoperative measures to increased the volume of the peritoneal cavity (e.g. progressive pneumoperitoneum by air of CO2 insufflation) have also been described.

 

Open Suture Repair

  • This technique is probably only suitable for small defects (<3-4cm).

  • If the edges of the defect can be apposed without tension, the defect is closed directly with strong nonabsorbable monofilament sutures.

 

Open Mesh Repair

  • Choice of mesh depends on desired weight and the type of tissue that the mesh will be in contact with.

  • Common mesh materials include polypropylene (e.g. Prolene, lightweight Vypro) and polyethylene (e.g. Mersilene), but these are not suitable for intra-peritoneal use.

  • Expanded polytetrafluoroethylene (ePTFE), composite and biological meshes can be used in contact with abdominal contents.

  • Composite meshes comprise a polypropylene or polyethylene mesh layer combined with a barrier layer (e.g. porcine dermal collagen – Permacol, human dermis – FlexHD)

  • The mesh may be laid “onlay” (the fascial defect is closed and a mesh is sutured in place to ensure 5cm overlap), “inlay” (the fascial defect is not closed and the mesh is sutured to the fascial edges), or “sublay” (the mesh is placed superior to the posterior rectus sheath and peritoneum,but inferior to rectus).

  • Sublay technique is an excellent choice but is technically more difficult.

  • Inlay technique may be associated with a higher rate of recurrence and an increased risk of enterocutaneous fistulas at the edge of the mesh.

  • Prophylactic antibiotics are used in cases of mesh repair.

  • This technique carries the risk of mesh infection and seroma formation.

 

Laparoscopic Mesh Repair

  • Intraperitoneal onlay mesh (IPOM) technique is most commonly used.

  • The mesh is usually secured in place using a ‘double crown’ of metal tacks ensuring a 3-5cm overlap of the fascial defect.

  • A specific complication of laparoscopic repair may include unrecognized bowel perforation.

  • Metanalysis suggests no difference in recurrence rates between open and laparoscopic surgery. However, laparoscopic repair may be associated with fewer wound infections, and trend toward fewer haemorrhagic complications and infections requiring mesh removal.

  • Relative contraindications to laparoscopic repair include previous abdominal surgery with dense adhesions, acute presentation with bowel ischaemia, and loss of domain.

 

Ramirez Component Separation Technique

  • Involves detachment of external oblique aponeurosis from rectus, and development of a plane between external and internal oblique aponeuroses.

  • Further mobilization of the rectus can be achieved by incising medial border of posterior rectus sheath (‘sliding door’ technique).

  • Can be used to close defects of 20cm in diameter (can advance rectus abdominis, anterior rectus sheath and internal oblique 10cm to the midline on either side).

  • Can be combined with onlay mesh technique,

  • Alternative relaxing techniques include multiple small incisions in fascial layers, muscular attachments and external oblique aponeuroses, ensuring preservation of blood supply and innervation of abdominal wall.

 

Prevention

  • Transverse incisions have a lower incidence of incisional herniation compared with vertical midline laparotomy wounds

  • Close all laparoscopic port sites of 10mm or more, especially when stretched during removal of a solid viscus e.g. gallbladder.

  • Identify and repair pre-existing umbilical hernias at the time of laparoscopic surgery.

  • Minimise the risk of wound infection.


Further Reading:


Back