What is the role of mesh in an open inguinal hernia repair?

Updated: Jan 17, 2018
  • Author: Vinay Kumar Kapoor, MBBS, MS, FRCS, FAMS; Chief Editor: Kurt E Roberts, MD  more...
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Answer

Emphasizing the Halsted principle of no tension, the Lichtenstein group advocated routine use of mesh in 1984. The prosthesis used to reinforce the weakened posterior wall of the inguinal canal is placed between the transversalis fascia and the external oblique aponeurosis and extends well beyond the Hesselbach triangle. Mesh implants do not actively shrink, but they are passively compressed by the natural process of wound healing. Mesh shrinkage occurs only to the extent to which the tissue contracts.

A mesh with a small pore size is likely to shrink more. Shrinkage of the different types of mesh in vivo is in the range of 20-40%; thus, it is important for the surgeon to ensure that the mesh adequately overlaps the defect on all sides. It is advisable to use a large (eg, 7.5 × 15 cm) sheet of mesh extending approximately 2 cm medial to the pubic tubercle, 3-4 cm above the Hesselbach triangle, and 5-6 cm lateral to the internal ring so as to allow for mesh shrinkage.

Although the use of traditional microporous or heavyweight polypropylene meshes over the past two decades has reduced the recurrence rate after hernia surgery to less than 1%, a major concern has been the formation of a rigid scar plate that causes patient discomfort and chronic pain, impairing quality of life. More than 50% of patients with a large mesh prosthesis in the abdominal wall complain of paresthesia, palpable stiff edges of the mesh, or physical restriction of abdominal wall mobility. [4]

It was assumed that the flexibility of the abdominal wall is restricted by implantation of excessive foreign material and by excessive scar tissue formation. A better knowledge of the biomechanics of the abdominal wall and the influence of mesh on those mechanics has led to the current understanding that “less is more.”

In other words, a less-dense, lighter-weight mesh with larger pores, though still stronger than the abdominal wall and thus usable for the purposes of repair, will result in less inflammation, better incorporation, better abdominal wall compliance, greater abdominal wall flexibility, less pain, and possibly less scar contraction; therefore, its use will lead to a better clinical outcome. [5, 25]

Lightweight composite mesh was developed in the conviction that the ideal mesh should be just strong enough to handle the pressure of the abdominal wall while remaining as low in mass and as thin as possible. The advantage of increasing the mesh pore size is that it makes it easier for tissue to grow through the pores and thereby create a thinner, better-integrated scar.

The newer lightweight composite meshes offer a combination of thinner filament size, larger pore size, reduced mass, and increased percentage of absorbable material. Thus, less foreign material is implanted, the scar tissue has greater flexibility (with almost physiologic abdominal wall mobility), there are fewer patient complaints, and the patient’s quality of life is better.

The use of lightweight mesh for Lichtenstein hernia repair has not been shown to affect recurrence rates, but it has been found to improve some aspects of pain and discomfort 3 years after surgery. [26] According to data from randomized, controlled trials and retrospective studies, light meshes seem to have some advantages with respect to postoperative pain and foreign body sensation. [5, 27]


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