Materials for inguinal hernia repair: Mesh and Fixation Bruce Ramshaw MD FACS Consultant, Halifax Health Daytona Beach, FL

Mesh Basics Multiple types of mesh Synthetic Biologic Alloderm Polypropelene PTFE Polyester Biologic Alloderm Surgisis Permacol Many others

Prosthetic Biomaterials Metal Synthetic Biomaterials Silver Wire Germany - 1910 United States - 1903 Limited tensile strength Limited pliability Corrode/oxidize Migrating fragments Wound infections

Stainless Steel Haas 1958

Prosthetic Biomaterials Monofilament fibers woven - 1958 Usher et al. Am Surg 24:969, 1958 knitted - 1962 Gained popularity during the Vietnam war Most commonly used mesh worldwide Francis Usher, MD

Prosthetic Biomaterials Polypropylene Mesh Marlex (C.R. Bard, Murray Hill, NJ) Initially woven - single strand Knitted modification

Prosthetic Biomaterials Prolene: double stranded polypropylene (Ethicon)

Prosthetic Biomaterials Surgipro (United States Surgical Corp, Norwalk, CT) multiple monofilaments polypropylene

Prosthetic Biomaterials Polyester Fiber- Hydrophilic Europe - 1960s / Rives and Stoppa - 1989 Thin, pliable, and elastic Conform to the visceral sac Rapid fibroblast ingrowth (true ingrowth)

Prosthetic Biomaterials Polytetrafluoroethylene (PTFE) Solid PTFE - early poor results Microporus PTFE - 1970’s Dual Mesh - 1994 two-sided: interstitial spacing 3 microns vs >100 microns Dual Mesh Plus - 1997 antimicrobial additive

Lightweight vs heavy weight mesh Hydrophilic Large pores >1mm > Elasticity 20-35% < Foreign body reaction Heavyweight/ Hydrophobic Small pores <1mm <Elasticity 4-16% > Foreign body reaction

Mesh Contraction and Migration

Original size

Mesh Contraction- Recurrence

Mesh Contraction- Recurrence

Heavyweight Polypropylene Hydrophobic Chronic inflammatory reaction Significant contraction Poor compliance

Mesh Comparison

Heavyweight Polypropylene Mesh Comparison Polyester Heavyweight Polypropylene

Mesh Comparison: Eight 10 x 10 cm pieces of mesh implanted for three months Two polypropylene mesh infections PE mesh: 86.8 +/- 7 cm2 PP (Hvywt.) mesh: 67.1 +/- 14 cm2 Histology and mechanism of ingrowth are different Tensile strength is less with PP (194N vs. 159N)

Cutaneous Nerve

Fixation

Fixation When Tacking, Where to Tack Trend toward limited tacks Fixation for Inguinal Hernia Fixation When Tacking, Where to Tack Trend toward limited tacks Coopers ligament (inferior-medial) Rectus Sheath (superior-medial) Above ASIS (lateral)

Fixation To Tack or Not to Tack Fixation for Inguinal Hernia Fixation To Tack or Not to Tack Does fixation reduce risk of recurrence? Does non-fixation reduce risk of post-op pain? Moreno-Egea et al. RCT Fixation v. No Fixation in 170 patients. Archives Nov, 2004. No difference in recurrence or chronic pain.

Inguinodynia- Removing tack

Fixation Alternative to Tacking Absorbable Tacks Fixation for Inguinal Hernia Fixation Alternative to Tacking Absorbable Tacks Good: Temporary Fixation (6 to 18 months) Bad: may increase cost 5 mm available are inferior to the tacks (strength)

Absorbable Tack Fixation: Bard and Covidien

Fixation Alternatives to Tacking Fibrin Glue application Fixation for Inguinal Hernia Fixation Alternatives to Tacking Fibrin Glue application Lau et al. RCT of Fibrin Glue v. Tack Fixation Annals Nov, 2005. Zero recurrences in both groups, 20% v. 13.5% chronic pain (p=0.4) Good: Temporary mesh stabilization Bad: may increase cost, cumbersome application device (though improving)

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