(BQ) Part 2 book Master techniques in surgery hernia presentation of content: Laparoscopic transabdominal preperitoneal inguinal hernia repair, totally extraperitoneal inguinal hernia repair, onlay mesh repair, sports hernia, umbilical hernia repair, massive ventral hernia with loss of domain, components separation,...and other contents.
Open Abdominal Wall Hernia 23 Choice of Mesh Arthur Rawlings and Brent D Matthews lfwe could artificially produce tissue of the density and toughness offascia and tendon, the secret of the radical cure of hernia repair would be discovered Theodore Bilroth (1829-1894) Introduction Edoardo Bassini ushered in the modem era of hernia repair in 1887 with his "radical cure" for an inguinal hernia on the basis of an anatomical repair Despite improved understanding of abdominal wall anatomy, the advent of aseptic technique, the development of antibiotic therapy for prophylaxis, and refined surgical skills over the decades, recurrence from a tissue repair of an abdominal wall hernia occurs at an alarming rate This is not the "radical cure" that Bassini envisioned for an inguinal hernia nor for any abdominal wall hernia For example, one study showed that a primary repair of a large ventral hernia is reported to have a 63% recurrence rate at 10 years This is reduced to 32% if a mesh is used to augment the primary closure If the hernia is small, less than 10 cm2 , then the recurrence rate for a primary repair is 67%, whereas it drops to 17% if a mesh is used to augment the repair Though there is much to learn about hernia anatomy and its usefulness in repair, studies have demonstrated that a mesh should be a primary tool for an abdominal wall hernia repair A mesh should be used unless there is a compelling reason not to use one With so many options available the question becomes, "Which one?" What is the Ideal Mesh? Before discussing what is available, it would be a good exercise to consider what would be an ideal mesh What is being asked from a piece of mesh in an abdominal wall hernia repair? There are several desired characteristics, some absolute while others only highly desirable The ideal mesh would be (in no significant order): Noncarcinogenic Strong enough to prevent a recurrence Easy to handle 245 246 Part Ill Open Abdominal Wall Hernia Easy to manufacture Economical Biocompatible: Having a minimally adverse or no inflammatory host response, or being completely remodeled into the host tissue Treatable if it becomes infected Undetected by the patient or by physical examination Compatible with future abdominal access 10 Nonallergenic or causing no hypersensitivity reaction On looking over the list, it is easy to say that the ideal mesh has yet to be produced This does give a good benchmark for the evaluation of what is on the market and a goal for future developments What is Available? Phelps used the first man-made prosthetic material for hernia repair in 1894 He placed silver wire coils in the floor of the inguinal canal and closed the layers of the abdominal wall over them He relied on the host response to this foreign body to increase the fibrosis in the inguinal :floor to reinforce the hernia repair This was further developed by German surgeons who used hand-made silver filigrees, fine silver wire woven into a net, as the first "mesh" to be routinely used for hernia repairs Though this has fallen out of favor, metal mesh for hernia repair was used longer than any other prosthetic material for hernia repair, including even the most popular materials used today Francis Usher initiated the current revolution in prosthetic materials for hernia repair when he published his use of polypropylene mesh for hernia repair in 1958 Since then many materials have come and gone; a few have stayed Through all the experiments and trials, three nonbiologic mesh materials have stood the test of time: Polypropylene, polyester, and polytetra:fluoroethylene (PTFE) Polypropylene Polypropylene, the mesh used by Usher, is a polymer of a carbon backbone with hydrogen and methyl groups attached (Fig 23.1) It looks as if it would be inert in the human host, but this structure initially undergoes oxidation at the tertiary carbons, which then can progress to oxidation of the carbon backbone The impact of this clinically is that explanted meshes have shown oxidative damage with surface cracking, a decrease in Figure 23.1 Knitted monofilament polypropylene mesh Photo courtesy of Corey Deeken, PhD Chapter 2.3 Choice of Mash 241 Fig1re 2!2 Woven polyester mesh Photo courtesy of Corey Deeken, PhD mass, and reduced compliance This polymer can be manufactured into weaves or knits of different patterns and densities Absorbable strands can also be woven together with the polypropylene to give the mesh a stiffer feel and easier handling characteristics for implantation, which will then become more pliable in the patient as the body degrades the absorbable strands ., ·e CD :I: ~ ;;; Polyester Polyester is a polymer of a carbon and oxygen backbone with hydrogen and oxygen attached (Fig 23.2) This polymer comes in many different forms, polyethylene terephthalate (PET or Dacron) being one of the most common Its versatility and strength to weight ratio make it a popular fabric for clothing This material also looks as if it would be inert in the human host, but that is not the case Polyester is hydrophilic and undergoes hydrolysis whereas polypropylene is hydrophobic and undergoes oxidation The hydrolysis of polyester can break the backbone of the polymer in a slow process that eventually can tum the polymer into a monomer For example, one study looked at 65 explanted polyester vascular grafts and showed by a linear regression model that the bursting strength is reduced by 31.4% at 10 years and 100% by 25 to 39 years The clinical significance for this in abdominal hernia repair is not fully known, but it does highlight that these seemingly inert materials undergo change in the human host In general terms, polyester tends to have less scar contraction, less tissue adherence, and feels softer than polypropylene Polytetrafl.uoroethylene (PTFE) Polytetrafluoroethylene (PTFH) is a polymer of fl.uorine atoms attached to a carbon backbone (Figs 23.3 and 23.4) Its most commonly known commercial applications are ·e.,c Cl a ldJJ oboM poUoat or tlao ~ Ia oil primaily cloood it "'"1 - Jalmebcl-'"•' p- tl-llftacy lti- ,_ n 'llldla1il p1 tlllllJ' , , , , wall b.llld& ,.W II ~ a J.!ntCiaul _~ p plo of oponlloa CJhdnol !mol n pall.d eo:DMPW u ~ cb-nda ptlD., ,.naJ ••q tJ • U.Jlll • u mmpliadu, tloo doWWo-4ll - ~) """ oPI"PB (Gooo-"l'ooin "-""' "" ono