What type of mesh is recommended for use in a setting with increased infection risk?

Mesh Selection for Increased Infection Risk Settings

In settings with increased infection risk, biological meshes are recommended over synthetic meshes, with cross-linked biological meshes showing lower recurrence rates compared to non-cross-linked meshes. 1

Types of Meshes and Their Performance in Contaminated Fields

Biological Meshes

Biological meshes are preferred in contaminated surgical fields due to their ability to become vascularized and remodeled into autologous tissue after implantation. They offer a collagen-based extracellular matrix scaffold that supports host fibroblast infiltration, angiogenesis, and new collagen deposition 1.

Key characteristics of biological meshes:

• Cross-linked biological meshes (e.g., Permacol):

  • Show significantly lower recurrence rates (5.8-12% at 12 months) 1
  • Better resist mechanical stress for longer periods 1
  • Recommended for larger defects with higher contamination 1

• Non-cross-linked biological meshes (e.g., Strattice):

  • Higher recurrence rates (14.2% higher than cross-linked meshes) 1
  • May have variable infection resistance depending on pathogen type 2

Synthetic Meshes

In contaminated fields (CDC wound class III), synthetic meshes show high infection rates:

• 21% infection rate in emergency and elective incisional hernia repairs 1
• 19% infection rate in contaminated fields 1

Comparative Performance

Recent evidence challenges the traditional view that biological meshes are always superior to synthetic meshes in contaminated fields:

• One experimental study showed that macroporous synthetic mesh (Parietex Progrip) demonstrated superior bacterial clearance compared to biological mesh (Strattice) (81% vs 36% combined bacterial strains clearance) 2
• Biological meshes may have different resistance patterns to different pathogens, with particular vulnerability to E. coli 2

Decision Algorithm for Mesh Selection in Increased Infection Risk

1. Assess defect size:

   • For small defects (<3 cm): Primary repair without mesh is recommended 1
   • For larger defects: Proceed to mesh selection

2. Evaluate contamination level:

   • For contaminated/dirty fields (CDC wound class III/IV): Choose biological mesh 1
   • For potentially contaminated fields: Consider patient-specific factors

3. Select biological mesh type based on defect characteristics:

   • Larger defects with higher contamination: Cross-linked biological mesh (e.g., Permacol) 1
   • Smaller defects with moderate contamination: Non-cross-linked biological mesh may be considered

4. If biological mesh is unavailable:

   • Consider polyglactin mesh repair or
   • Consider open wound management with delayed repair 1

Important Considerations and Pitfalls

1. Avoid bridging repairs when possible:

   • Bridge repairs with biological mesh have shown high recurrence rates (20.5%) 3
   • Primary fascial closure with mesh reinforcement is preferred whenever feasible 4

2. Risk factors for mesh infection:

   • Smoking (RR = 1.36)
   • ASA score ≥3 (RR = 1.40)
   • Emergency operation (RR = 2.46)
   • Prolonged operative duration 1

3. Management of infected mesh:

   • Complete surgical removal of infected mesh is the only way to eradicate infection 1
   • Early and adequate local source control plus antibiotics can help prevent mesh contamination following incisional surgical site infection 1

4. Mesh positioning considerations:

   • Both onlay and retromuscular positions are recommended in emergency surgery 1
   • Component separation techniques may be needed to achieve primary fascial closure 4

Emerging Evidence

Recent research suggests that reinforced biologic mesh (reinforced biologic ovine rumen) may reduce complications compared to other biologic mesh types:

• Lower complication rates (16.7%) compared to non-cross-linked porcine ADM (47.1%), cross-linked porcine ADM (52.9%), and bovine ADM (43.2%) 5
• Lower relative risk for hernia recurrence 5

However, this evidence is from a single retrospective study and needs further validation before changing current recommendations that favor cross-linked biological meshes.