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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Anatomy of inguinal canal.
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Anatomy of nerves of groin.
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Open inguinal hernia repair. Skin incision.
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Open inguinal hernia repair. Division of external oblique aponeurosis.
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Open inguinal hernia repair. Cord structures and hernia sac encircled by Penrose drain.
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Open inguinal hernia repair. Hernia sac separated from cord structures.
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Open inguinal hernia repair. Development of preperitoneal space.
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Open inguinal hernia repair. Deployment of Prolene Hernia System (PHS).
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Open inguinal hernia repair. Final position of Prolene Hernia System (PHS) mesh.
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Open inguinal hernia repair. Closure of external oblique aponeurosis.
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Open inguinal hernia repair. Skin closure.
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Open inguinal hernia repair. Draping and incision.
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Open inguinal hernia repair. External oblique aponeurosis with external inguinal ring.
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Open inguinal hernia repair. External oblique aponeurosis with external inguinal ring.
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Open inguinal hernia repair. Reflected part of inguinal ligament exposed for fixing inferior edge of mesh.
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Open inguinal hernia repair. Inferior flap of external oblique aponeurosis developed to expose inguinal ligament from pubic tubercle to midinguinal point.
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Open inguinal hernia repair. Superior flap of external oblique aponeurosis is developed as high as possible to provide ample space for mesh placement.
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Open inguinal hernia repair. Lifting up cord with hernia sac medial to external inguinal ring.
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Open inguinal hernia repair. Avascular plane between posterior inguinal wall and cord structures.
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Open inguinal hernia repair. Cord structures and hernia sac looped along with ilioinguinal and genitofemoral nerves.
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Open inguinal hernia repair. Cremaster muscle picked up to be incised longitudinally between hemostats.
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Open inguinal hernia repair. Indirect hernia sac dissected and being separated from lipoma of cord and cord structures.
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Open inguinal hernia repair. Lipoma of cord dissected free and excised.
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Open inguinal hernia repair. Indirect hernia sac separated from cord structures in midinguinal region toward neck of sac.
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Open inguinal hernia repair. Voluminous indirect hernia sac separated from cord structures in midinguinal region up to neck of sac.
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Open inguinal hernia repair. Hernia sac being divided near neck.
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Open inguinal hernia repair. Contents of hernia sac reduced and proximal end to be sutured closed.
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Open inguinal hernia repair. Anterior wall of distal sac incised to prevent hydrocele formation.
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Open inguinal hernia repair. Fixation of lower edge of mesh.
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Open inguinal hernia repair. First medialmost stitch in mesh, fixed about 2 cm medial to pubic tubercle, where anterior rectus sheath inserts into pubis.
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Open inguinal hernia repair. Same suture is utilized as continuous suture to fix lower edge of mesh to reflected part of inguinal ligament up to internal ring.
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Open inguinal hernia repair. Lower edge of mesh sutured to inguinal ligament up to internal inguinal ring. To accommodate cord structures, lateral end of mesh is divided into wider upper (two thirds) tail and narrower lower (one third) tail.
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Open inguinal hernia repair. Wider upper tail of mesh is passed underneath cord, and mesh is placed posteriorly in inguinal canal behind spermatic cord.
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Open inguinal hernia repair. Fixation of upper edge of mesh.
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Open inguinal hernia repair. Slit made in mesh to accommodate iliohypogastric nerve. Two interrupted sutures are taken under vision to fix upper edge of mesh while safeguarding iliohypogastric nerve.
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Open inguinal hernia repair. Upper tail is crossed over lower tail around spermatic cord, thus creating internal ring. Lower edges of two tails are tucked together to inguinal ligament just lateral to internal ring.
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Open inguinal hernia repair. Tails are then passed underneath external oblique aponeurosis to give overlap of about 5 cm beyond internal ring.
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Open inguinal hernia repair. External oblique aponeurosis sutured with 2-0 polypropylene.
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Open inguinal hernia repair. Subcutaneous tissue approximated with 3-0 plain catgut.
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Open inguinal hernia repair. Skin approximated with 2-0 polypropylene subcuticular suture.
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Hesselbach triangle. Image courtesy of Wikimedia Commons.
