Infected hernia mesh

A 46-year-old lady presented with an abscess in the umbilicus. She had a laparoscopic umbilical hernia repair done 4 years previously. Operative photographs are shown in Figure 1.

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Figure 1:

(a) Abscess cavity with free lying tacker. (b) Mesh being explanted intoto.

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Usher, in 1959, first described the use of polypropylene mesh in the repair of hernias to reinforce the abdominal wall. Since then, many open and laparoscopic techniques have been described with the mesh being placed in various layers of the abdominal wall. Using a mesh prosthesis is now considered the standard technique and is currently the most effective method to prevent hernia recurrence.^[1]

Synthetic meshes used for hernia surgery act as a foreign body, inducing aseptic inflammation and eventually fibrosis. It is this foreign body property of the mesh that also leads to its associated complications, such as seroma, chronic pain, intestinal obstruction and infection.^[1] Infection rates following open surgery vary from 6 to 10% and following laparoscopic surgery, they range from 0 to 3%.

Infection of the mesh is one of the most dreaded complications for any surgeon.

There are certain risk factors which can predict mesh infection. Patient factors such as comorbid conditions (Diabetes mellitus, chronic obstructive pulmonary disease and obesity), plane of mesh placement (Increased chance of infection with meshes placed superficially when compared to sublay), type of mesh used (Meshes which are absorbable and have larger pore size are less prone to infection compared to non-absorbable and small pore size meshes), technical aspects such as handling of the mesh, improper sterilisation of instruments and reusing leftover meshes and tackers.^[2]

Mesh infection can be classified as primary (following hernia surgery) and secondary (Following subsequent surgery for some other cause).

Mesh infection may present as:

1. Periprosthetic fluid collection with clinical findings consistent with infection (cellulitis, purulent wound drainage, fever and leucocytosis)

2. Periprosthetic, culture-positive fluid collection

3. Chronic draining sinus confirmed as a mesh infection

4. Exposed mesh

5. Enterocutaneous fistula through an area of the abdominal wall containing mesh. These symptoms or signs may present any time after surgery, sometimes even after 1 year following surgery.^[3]

The most common source of infection is from the flora of the skin, with the most common organism being Staphylococcus aureus (>60% of cases across various studies). Ultrasound of the abdomen is the first choice of investigation to assess fluid collection and its nature. However, to distinguish between a large seroma and an infected collection around the mesh, contrast-enhanced computed tomography would be preferable.

Definitive treatment of an infected mesh is complete explantation (removal of the mesh), including the transfascial sutures and all the tackers used. However, this can lead to increase in the size of the defect and thereby cause a larger hernia with loss of domain. Mesh explantation also carries with it the risk of hernia recurrence. The absolute indications for mesh explantation are the presence of a loose lying mesh in an abscess cavity and the presence of an enterocutaneous fistula at the site of the mesh. Following explantation of mesh, when fascia closure was not done, recurrence was seen in almost all patients, and, in cases, where fascia was closed, the recurrence was about 50%. While there are reports of laparoscopic removal of an infected mesh, an open operation is generally recommended for thorough clearance of the mesh and infection. Repair with another prosthetic mesh is recommended once the patient has completely recovered from the infection which is probably 6–9 months later but this carries the morbidity of another surgery.^[1]

Alternate management option includes mesh salvage wherein we start the patient on broad-spectrum antibiotics effective against Gram-positive cocci and drain the collection either percutaneously or by surgical debridement. Sinuses, if any, are laid open surgically. Negative pressure therapy is very valuable as it promotes wound healing by continuous reduction of interstitial fluid and the bacterial load. It causes shrinkage of the wound and induces regeneration of tissue.^[2]

Partial salvage of the mesh has also been practised, wherein, after a thorough examination, the healthy part of the mesh is left behind; but this carries with it the risk of recurrence of infection and the possibility of an additional surgery to explant the remaining mesh. We would not recommend partial salvage.

Macroporous monofilament meshes have a higher salvage rate in view of better tissue ingrowth into the mesh, which allows migration of leukocytes and hence clearance of infection.

Similarly absorbable meshes which generally get absorbed in 60–70 days also facilitate leukocyte migration.^[2]

It is not recommended to prolong conservative treatment in case of mesh infection in patients operated for recurrent hernia, as they have a worse potential of resolving a mesh infection without removal of the mesh due to an increase in fibrotic tissue at the site of the operation. While no specific data are available for the optimal length of conservative treatment, waiting beyond 3 months for explantation seems futile.

In conclusion, timely diagnosis of a periprosthetic infection, broad-spectrum antibiotics and aggressive local wound care are the first line of management. If there is failure of resolution of infection, then it is better to go ahead and do a mesh explantation rather than prolong salvage therapy.