**2. Anatomy of the inguinal region**

The inguinal canal is located at the midpoint of the inguinal ligament that runs between the anterior superior iliac spine (ASIS) and the pubic tubercle. It is about 5 cm long and passes obliquely downward and inward. It is bounded by four walls: anteriorly, the aponeurosis of the external oblique muscle; posteriorly, the transversalis fascia; superiorly (roof), the fascia of the internal oblique and transverse abdominal muscles (joined by the conjoint tendon in 5% of cases); and inferiorly (floor), the rolled up portion (lacunar ligament) of the inguinal ligament. The deep inguinal ring is an opening in the transversalis fascia; it is located between the epigastric vessels and the fascia of the internal oblique and the transverse muscles and reinforced by Hesselbach's ligament. The superficial inguinal ring is a triangular opening formed by the external oblique where it inserts on the pubic crest and the pubic tubercle. It is bounded on either side by the margins of the opening in the aponeurosis, the crura of the ring. Lying superficial to the inguinal aponeurosis and deep to the superficial abdominal ring is Colles' ligament (reflected inguinal ligament), a triangular fibrous connective tissue band running from the pubic bone and lacunar ligament medially and upward to the linea alba [11–13].

The posterior wall of the inguinal canal is reinforced laterally by Hesselbach's (interfoveolar) ligament, medially by the conjoint tendon, and the reflected part of Colles' ligament at the distal end of Henle's ligament (formed by the union of the inferior terminal fibers of the aponeurosis of the transverse muscle and the iliopubic band) and is present only in the central part of the transversalis fascia. This oval area is particularly weak between the lower edge of the aponeurosis of the transverse muscle superiorly, the iliopubic band (thickening of the transversalis fascia near the inguinal ligament) inferiorly, Henle's ligament at the medial end, the junction of the inferior edge of the transverse muscle, and the iliopubic band at the lateral end (**Figure 2**) [11–13].

**Figure 2.** (1) Transversalis fascia (inguinal hiatus), (2) falx inguinalis, (3) inguinal ligament (iliopubic band), (A) lateral fossa (origin of external oblique inguinal hernia), (B) middle fossa (origin of direct inguinal hernia), (C) medial fossa (origin of internal oblique inguinal hernia.

the wall using a triple layer in which the transversalis fascia, along with the internal oblique and the transverse muscles, was sutured to the posterior border of the inguinal (Poupart's) ligament. The drawback to this technique was that tension on the sutures led to high rates of hernia recurrence. To demonstrate the retainment capability of the transversalis fascia, Bassini showed that incidence of recurrence was higher when a double layer comprising only the internal oblique and the transverse muscles was employed to repair the defect. Later, Lichtenstein and Trabucco independently understood the need to reinforce the wall weakness using instead of sutures a mesh prosthesis with or without placing a "plug" in the weak point of the transversalis fascia. The drastic reduction in recurrence rates with the use of these techniques has made prosthesis hernioplasty the gold standard in inguinal hernia repair [1, 2].

**Figure 3.** (1) Epigastric vessels, (2) spermatic cord, (3) transversalis fascia, (4) remnant of umbilical artery, (5) external

All-in-One Mesh Hernioplasty: A New Procedure for Inguinal Hernia Repair

http://dx.doi.org/10.5772/intechopen.75387

45

oblique inguinal hernia, (6) direct inguinal hernia, (7) internal oblique inguinal hernia.

Observing the anatomy of the transversalis fascia, we can imagine it as a thin layer lining the abdominal cavity, contracting relationships with the muscles and aponeurotic and bony structures. Cephalad fuses with the diaphragmatic fascia, in contact with the lower ribs, the first lumbar vertebrae, and the lumbodorsal fascia. Inferolaterally, it is continuous with the psoas fascia and the quadratus lumborum muscles and anteriorly with the rectus abdominis muscles and the aponeurosis of the transverse muscle. The image is that of a sac hung on the musculoaponeurotic and bony structures of the upper abdomen, with posterior and lateral connections in which the only area of passage is the semicircular arch of Douglas. The transversalis fascia then thickens medially (Henle's ligament) at the lateral concave edge (he called it the falx inguinalis) which inserts at its base in Cooper's ligament and anteriorly attaches to the conjoint tendon [11–13].

More lateral to the arch of Douglas is a thickening that continues to Hesselbach's (interfoveolar) ligament and inserts between the two fossas, the superficial inguinal ring and the medial fossa. It then inserts in the inguinal ligament after having circled the deep inguinal ring inferiorly. More laterally, the transversalis fascia forms a U-shaped sling around the ring and is continuous with the internal spermatic fascia. The so-called transversalis fascial sling, on contraction of the transverse muscle due to increased intra-abdominal pressure, is flattened at

This area of weakness comprises the deep inguinal ring, the site of indirect hernias, the area underlying it, and the site of direct hernias. Topographically, beneath the transversalis fascia, the inferior epigastric vessels run vertically and medially to the deep inguinal ring. Medial to the epigastric vessels and passing outward and downward is the remnant of the umbilical artery. Based on their relationship with the epigastric vessels and the remnant of the umbilical artery (**Figure 3**), three types of hernia can be distinguished:


This universally recognized classification of inguinal hernia was recently simplified by the European Hernia Society into two areas of weakness of the inguinal canal floor: the medial area (direct hernias) and the lateral area (indirect hernias) [14].

Detailed anatomic study of the inguinal region shows how the transversalis fascia, together with the aponeurosis of the oblique internal and transverse abdominal muscles, by virtue of their anatomic structure and function, works to retain the content of the abdominal cavity. The aponeurosis of the external oblique muscle appears to have two roles: to cover and to oppose intra-abdominal pressure. In 1884 Edoardo Bassini conceived of a method to reinforce

**Figure 3.** (1) Epigastric vessels, (2) spermatic cord, (3) transversalis fascia, (4) remnant of umbilical artery, (5) external oblique inguinal hernia, (6) direct inguinal hernia, (7) internal oblique inguinal hernia.

This area of weakness comprises the deep inguinal ring, the site of indirect hernias, the area underlying it, and the site of direct hernias. Topographically, beneath the transversalis fascia, the inferior epigastric vessels run vertically and medially to the deep inguinal ring. Medial to the epigastric vessels and passing outward and downward is the remnant of the umbilical artery. Based on their relationship with the epigastric vessels and the remnant of the umbilical

**Figure 2.** (1) Transversalis fascia (inguinal hiatus), (2) falx inguinalis, (3) inguinal ligament (iliopubic band), (A) lateral fossa (origin of external oblique inguinal hernia), (B) middle fossa (origin of direct inguinal hernia), (C) medial fossa

**1.** External oblique hernia originates from the deep inguinal ring in an area of weakness

**2.** Direct hernia originates from an aperture in the posterior wall of the inguinal canal between the epigastric vessels and the remnant umbilical artery in an area of weakness

**3.** Internal oblique hernia protrudes medially to the site of direct hernia in an area of weakness between the remnant of the umbilical artery and the urachus, termed the medial fossa. This type of hernia occurs rarely owing to the protective effect of the conjoint tendon,

This universally recognized classification of inguinal hernia was recently simplified by the European Hernia Society into two areas of weakness of the inguinal canal floor: the medial

Detailed anatomic study of the inguinal region shows how the transversalis fascia, together with the aponeurosis of the oblique internal and transverse abdominal muscles, by virtue of their anatomic structure and function, works to retain the content of the abdominal cavity. The aponeurosis of the external oblique muscle appears to have two roles: to cover and to oppose intra-abdominal pressure. In 1884 Edoardo Bassini conceived of a method to reinforce

artery (**Figure 3**), three types of hernia can be distinguished:

area (direct hernias) and the lateral area (indirect hernias) [14].

termed the lateral fossa.

(origin of internal oblique inguinal hernia.

44 Hernia Surgery and Recent Developments

termed the middle fossa.

Colles' ligament, and Henle's ligament.

the wall using a triple layer in which the transversalis fascia, along with the internal oblique and the transverse muscles, was sutured to the posterior border of the inguinal (Poupart's) ligament. The drawback to this technique was that tension on the sutures led to high rates of hernia recurrence. To demonstrate the retainment capability of the transversalis fascia, Bassini showed that incidence of recurrence was higher when a double layer comprising only the internal oblique and the transverse muscles was employed to repair the defect. Later, Lichtenstein and Trabucco independently understood the need to reinforce the wall weakness using instead of sutures a mesh prosthesis with or without placing a "plug" in the weak point of the transversalis fascia. The drastic reduction in recurrence rates with the use of these techniques has made prosthesis hernioplasty the gold standard in inguinal hernia repair [1, 2].

Observing the anatomy of the transversalis fascia, we can imagine it as a thin layer lining the abdominal cavity, contracting relationships with the muscles and aponeurotic and bony structures. Cephalad fuses with the diaphragmatic fascia, in contact with the lower ribs, the first lumbar vertebrae, and the lumbodorsal fascia. Inferolaterally, it is continuous with the psoas fascia and the quadratus lumborum muscles and anteriorly with the rectus abdominis muscles and the aponeurosis of the transverse muscle. The image is that of a sac hung on the musculoaponeurotic and bony structures of the upper abdomen, with posterior and lateral connections in which the only area of passage is the semicircular arch of Douglas. The transversalis fascia then thickens medially (Henle's ligament) at the lateral concave edge (he called it the falx inguinalis) which inserts at its base in Cooper's ligament and anteriorly attaches to the conjoint tendon [11–13].

More lateral to the arch of Douglas is a thickening that continues to Hesselbach's (interfoveolar) ligament and inserts between the two fossas, the superficial inguinal ring and the medial fossa. It then inserts in the inguinal ligament after having circled the deep inguinal ring inferiorly. More laterally, the transversalis fascia forms a U-shaped sling around the ring and is continuous with the internal spermatic fascia. The so-called transversalis fascial sling, on contraction of the transverse muscle due to increased intra-abdominal pressure, is flattened at its base, producing partial closure of the ring. The transversalis fascia performs a containing function by virtue of its bony and musculoaponeurotic attachments, particularly in the upper abdomen, attachment of Henle's ligament to Cooper's ligament and Hesselbach's ligament, and its attachment to the transverse muscle (transversalis fascial sling) and valve mechanism.

by increased intra-abdominal pressure. The abdominal cavity can be compared to a container holding a dense, viscous content. Since its walls are subject to the laws of plasticity, the content of the abdominal cavity exerts a force per unit area perpendicularly to a surface, commonly defined as pressure. An imbalance between the force of intra-abdominal pressure and resistance of the inguinal wall at an area of weakness of the inguinal canal can result in plastic deformation that will increase even when the pressure remains unchanged [15]. It is this deformation at the points of weakness of the transversalis fascia that leads to its weakening. The work by Wegh and Read showed that the fascia of hernia patients had low hydroxyproline content [16]. Histology demonstrated in many cases degeneration of collagen and elastic fibers in the musculoaponeurosis of the transverse muscle, like that seen in patients with Marfan syndrome [17, 18], apparently due to collagen catabolism because of a metabolic defect [18]. The use of prosthetic material that can promote rapid fibroblast proliferation is therefore required for reinforcing the inguinal wall and renders its resistance enough to ensure mesh stability after the patient has left the operating table, assumes the upright posi-

All-in-One Mesh Hernioplasty: A New Procedure for Inguinal Hernia Repair

http://dx.doi.org/10.5772/intechopen.75387

47

Lichtenstein procedures are performed in part directly on the transversalis fascia since the mesh is placed in the subaponeurotic space (anterior wall of the inguinal canal) [1], and Trabucco procedures involve the floor of the inguinal canal through the application of plugs. The use of isolated plugs does not reduce the risk of recurrence at the site of insertion nor recurrence at other sites due to differences in the distribution of pressure. Hence, there is a need to apply also a prosthetic mesh to reinforce the aponeurosis of the external oblique muscle [2]. The support mechanism is similar to that provided by hernia support garments that apply targeted compression to prevent failure of the inguinal canal floor due to elevation

The absence of tension on the musculoaponeurotic layer after application of a prosthetic mesh under the anterior wall of the inguinal canal has reduced hernia recurrence rates; however, this type of mesh can cause pain due to contact with the musculoaponeurotic and nerve structures or induce a foreign body sensation due to wrinkling of the mesh. Analysis of hernia recurrence causes shows that they always occur in an area beneath a subaponeurotic mesh that has become well integrated with the anterior wall of the inguinal canal. In a review of 1276 patients operated on for hernia recurrence, Lichtenstein found a hernia defect near the pubic tubercle in 47% of cases, at the deep inguinal ring in 40%, and involving the entire suture in 13% [1]. This gave rise to the idea of a tension-free mesh prosthesis designed to provide direct reinforcement of the entire area of weakness of the inguinal canal floor, thus restoring its normal function. In addition, a technique was developed to apply a mesh that would not interfere with nerves and muscles in the area. Mesh shape and size were derived from repeated measurement of the inguinal canal floor for targeted application. No isolated plugs or subaponeurotic patches are needed. The mesh conforms to anatomy, with the less use of foreign body

Furthermore, the presence of a missed hernia sac, which may be the cause of early hernia recurrence after a Lichtenstein or Trabucco procedure, is no longer possible. The areas of

material, thus reducing the risk of pain and increasing patient comfort.

tion, and begins to go about his daily activities.

of intra-abdominal pressure.

Other structures that assist in this function include:


The falx inguinalis, together with the inguinal ligament, forms the curved upper edge of the inguinal hiatus; its base is formed by the inguinal ligament (**Figure 2**). In healthy conditions, the falx inguinalis and the transversalis fascia contribute synergistically to retainment of the walls of the inguinal canal [11–13].

Three principal nerve structures pass through the inguinal canal:


### **2.1. Pathophysiological aspects**

Changes in strength and resistance of anatomical structures, often associated with congenital or acquired degenerative disorders, and remodeling of collagen and elastic fibers can lead to widening of the deep inguinal ring and weakening of the posterior wall of the inguinal canal by increased intra-abdominal pressure. The abdominal cavity can be compared to a container holding a dense, viscous content. Since its walls are subject to the laws of plasticity, the content of the abdominal cavity exerts a force per unit area perpendicularly to a surface, commonly defined as pressure. An imbalance between the force of intra-abdominal pressure and resistance of the inguinal wall at an area of weakness of the inguinal canal can result in plastic deformation that will increase even when the pressure remains unchanged [15]. It is this deformation at the points of weakness of the transversalis fascia that leads to its weakening.

its base, producing partial closure of the ring. The transversalis fascia performs a containing function by virtue of its bony and musculoaponeurotic attachments, particularly in the upper abdomen, attachment of Henle's ligament to Cooper's ligament and Hesselbach's ligament, and its attachment to the transverse muscle (transversalis fascial sling) and valve mechanism.

• The internal oblique muscle surrounding the deep inguinal ring superiorly and then forming the medial wall of the inguinal canal. Contraction of the transversus abdominis causes this structure to move down toward the inguinal (Keith) ligament in a kind of protective shutter mechanism, which reinforces the weakest area of the groin on elevation of intra-

• The transverse muscle, which forms the medial wall of the inguinal canal and, together with the internal oblique muscle, unites in the conjoint tendon. The conjoint tendon then forms a lateral concavity and inserts on the pubic symphysis, the pubic tubercle, and Cooper's ligament. Posteriorly, it fuses with Henle's ligament (falx inguinalis). When the transverse muscle contracts, the deep inguinal ring narrows via the action of Hesselbach's

• Colles' ligament is made of fibers of the aponeurosis of the contralateral external oblique

The falx inguinalis, together with the inguinal ligament, forms the curved upper edge of the inguinal hiatus; its base is formed by the inguinal ligament (**Figure 2**). In healthy conditions, the falx inguinalis and the transversalis fascia contribute synergistically to retainment of the

**1.** The iliohypogastric nerve (anterior branch) runs along the internal oblique muscle, parallel and cranial to the spermatic cord; it exits the inguinal canal through a small aperture above

**2.** The ilioinguinal nerve runs along the anterosuperior border of the spermatic cord between

**3.** The genital branch of the genitofemoral nerve enters the inguinal canal medial to the deep inguinal ring and runs along the posterolateral cremasteric fascia together with the exter-

Changes in strength and resistance of anatomical structures, often associated with congenital or acquired degenerative disorders, and remodeling of collagen and elastic fibers can lead to widening of the deep inguinal ring and weakening of the posterior wall of the inguinal canal

Other structures that assist in this function include:

ligament (Lytle's sling), another protective mechanism.

Three principal nerve structures pass through the inguinal canal:

muscle that crosses at the midline.

walls of the inguinal canal [11–13].

the superficial inguinal ring.

nal spermatic vessels [11–13].

**2.1. Pathophysiological aspects**

the cremasteric fibers.

abdominal pressure.

46 Hernia Surgery and Recent Developments

The work by Wegh and Read showed that the fascia of hernia patients had low hydroxyproline content [16]. Histology demonstrated in many cases degeneration of collagen and elastic fibers in the musculoaponeurosis of the transverse muscle, like that seen in patients with Marfan syndrome [17, 18], apparently due to collagen catabolism because of a metabolic defect [18]. The use of prosthetic material that can promote rapid fibroblast proliferation is therefore required for reinforcing the inguinal wall and renders its resistance enough to ensure mesh stability after the patient has left the operating table, assumes the upright position, and begins to go about his daily activities.

Lichtenstein procedures are performed in part directly on the transversalis fascia since the mesh is placed in the subaponeurotic space (anterior wall of the inguinal canal) [1], and Trabucco procedures involve the floor of the inguinal canal through the application of plugs. The use of isolated plugs does not reduce the risk of recurrence at the site of insertion nor recurrence at other sites due to differences in the distribution of pressure. Hence, there is a need to apply also a prosthetic mesh to reinforce the aponeurosis of the external oblique muscle [2]. The support mechanism is similar to that provided by hernia support garments that apply targeted compression to prevent failure of the inguinal canal floor due to elevation of intra-abdominal pressure.

The absence of tension on the musculoaponeurotic layer after application of a prosthetic mesh under the anterior wall of the inguinal canal has reduced hernia recurrence rates; however, this type of mesh can cause pain due to contact with the musculoaponeurotic and nerve structures or induce a foreign body sensation due to wrinkling of the mesh. Analysis of hernia recurrence causes shows that they always occur in an area beneath a subaponeurotic mesh that has become well integrated with the anterior wall of the inguinal canal. In a review of 1276 patients operated on for hernia recurrence, Lichtenstein found a hernia defect near the pubic tubercle in 47% of cases, at the deep inguinal ring in 40%, and involving the entire suture in 13% [1].

This gave rise to the idea of a tension-free mesh prosthesis designed to provide direct reinforcement of the entire area of weakness of the inguinal canal floor, thus restoring its normal function. In addition, a technique was developed to apply a mesh that would not interfere with nerves and muscles in the area. Mesh shape and size were derived from repeated measurement of the inguinal canal floor for targeted application. No isolated plugs or subaponeurotic patches are needed. The mesh conforms to anatomy, with the less use of foreign body material, thus reducing the risk of pain and increasing patient comfort.

Furthermore, the presence of a missed hernia sac, which may be the cause of early hernia recurrence after a Lichtenstein or Trabucco procedure, is no longer possible. The areas of weakness of the transversalis fascia at the floor of the inguinal canal are contemporaneously reinforced by apposition of a single prosthetic mesh designed to conform to the anatomy and function of the inguinal canal. The resulting rapid integration of fibroblasts into the mesh and the transversalis fascia strengthens the new wall, rendering the entire area of weakness of the inguinal canal floor more resistant to weakening under elevated intra-abdominal pressure.

voluminous prehernia lipoma can be resected or reduced in the abdominal cavity together with the hernia sac. If necessary, the deep inguinal ring is then narrowed with resorbable interrupted sutures. In all cases, the posterior wall is reinforced with the prosthetic mesh, as shown in **Figure 5**. This innovative, semiresorbable pre-cut mesh (70% polyglycolic acid and 30% polypropylene) is designed to reinforce the entire floor of the inguinal canal. It is shaped to conform to anatomy without the risk of wrinkling or need to trim it. Polypropylene is noted for its ability to induce an inflammatory fibrous reaction that promotes rapid, firm adhesion of the mesh onto tissues [19]. The mesh is available as a large*-*pore woven mesh that promotes infiltration and integration of connective tissue [16, 20, 21]. Less susceptible to bacterial colonization, the

All-in-One Mesh Hernioplasty: A New Procedure for Inguinal Hernia Repair

http://dx.doi.org/10.5772/intechopen.75387

49

Section A of the mesh is applied to surround the spermatic cord contents and form a cone around them by overlapping the two tails (A1 and A2). The length of the tails can be shortened to adjust the opening of the cone apex to the diameter of the spermatic cord. If present, diffuse lipomatosis

mesh can be left in place in case of infection [20, 22, 23].

**Figure 5.** "All-in-one mesh" device.
