CHICAGO – Infected ventral hernia mesh is most likely to be salvaged if it’s made from lightweight polypropylene, according to data from a series of 161 mesh infection cases at Carolinas Medical Center in Charlotte, N.C.
Investigators there were able to salvage 33% of lightweight polypropylene and 8% of polytetrafluoroethylene mesh patients, but salvage failed in patients with composite, polyester, or heavyweight polypropylene meshes. The overall salvage rate was less than 10%.
“We sometimes think that we’ve salvaged the mesh, but if we follow these patients long enough” – follow-up was an average of 37 months in the series – “the majority of them will need to be excised,” said investigator Dr. Vedra Augenstein of the department of surgery at the medical center.
Wound complications are common in ventral hernia repairs, and mesh infections, said Dr. Augenstein, are among “the most dreaded.” The North Carolina findings help define the small pool of patients in whom salvage might work.
The average body mass index in the series was 36 kg/m2, and patients had an average of 2.6 previous ventral hernia repairs. The majority had a polypropylene mesh. Most of the cases were referred to the medical center from elsewhere, so mesh excision came an average of 10 months after the diagnosis of infection.
Almost a third of patients had their infections diagnosed a year or more after mesh implant, which goes against the common notion that mesh patients are out of the woods after a year. “It took a very long time for some of these infections to present. This was a big surprise for us,” Dr. Augenstein said.
The team tried to salvage all of their patients, using antibiotics in 90%, vacuum-assisted closure and/or debridement in 57%, and percutaneous drainage in 17%.
No patient presented with an obvious fistula, but the investigators found fistulas during surgery in about 16% of patients. Meanwhile, salvage failed in every patient who continued to smoke despite being diagnosed with a mesh infection.
The team assembled their findings into an informal algorithm for considering mesh salvage.
“Think about what you need to ask yourself. First, does the patient have a fistula or do you suspect one” from, for instance, gut bacteria in the wound or oral contrast above the mesh on CT? If so, “they are going to need an operation,” Dr. Augenstein said.
Smoking is the next stop point; salvage is likely to fail in smokers.
Mesh type is the third consideration; lightweight polypropylene is a good sign. “If they have heavyweight polypropylene, composite, or polyester mesh, they were not salvageable in our series,” she said.
For patients still in the running, Methicillin-resistant Staphylococcus aureus (MRSA) is the next concern. If it’s in the wound, mesh is going to be harder to salvage, said Dr. Augenstein. Most of the infections in the series were caused by Staphylococcus, with MRSA present in 45% of patients.
Infection recurrence is common even when salvage seems to work, so “we need to follow these patients for a very, very long time,” Dr. Augenstein said.
Along with clinical exams, the North Carolina team follows C-reactive protein and erythrocyte sedimentation rate. “If the abdomen gets red or if, for example, the C-reactive protein goes up, we’ll do a CT scan or ultrasound to make sure they are not brewing an infection,” she said.
Dr. Augenstein has received research and educational grants from Gore, Ethicon, Novadaq, Bard, and LifeCell.