large midline abdominal wall defects.133 Originally, it was proposed as a tissue repair for patients with

contaminated wounds to avoid use of prosthesis, but several modifications have been described since

the original description. In this technique, the skin and subcutaneous fat are dissected free from the

anterior sheath of the rectus abdominis muscle and the aponeurosis of the external oblique muscle. The

aponeurosis of the external oblique muscle is transected longitudinally just lateral to the lateral side of

the rectus sheath (Fig. 72-33). It is important to extend the incision inferiorly up to the inguinal

ligament and superiorly onto the chest wall at least 5 to 7 cm cranial to the costal margin especially for

defects close to the xiphoid. The external oblique muscle is separated from the internal oblique muscle,

as far laterally as possible in a relatively avascular plane, beyond the area of skin undermining toward

the midaxillary line. This step is safe because the neurovascular bundle (comprising the intercostal

nerves and vessels) lies deep to the internal oblique muscle. The result is that the internal oblique

muscle and the rectus abdominis slide medially for about 7 to 10 cm. When necessary, 2 to 4 cm of

additional length can be gained by performing a posterior rectus release, separating the posterior rectus

sheath from the rectus abdominal muscle. This step may be difficult in patients who have scarring from

previous surgical procedures. Care must be taken not to damage the neurovascular bundle that runs

between the internal oblique and transversus abdominis muscle to enter the rectus sheath

posterolaterally. After advancement of the rectus complex toward the midline, the fascial closure is

performed followed by layered closure of the subcutaneous tissues and skin with drains. Several

modifications to the original technique have been described. The technique can also be used as an

adjuvant to the prosthetic repairs described next.

Posterior Component Separation. This technique is an extension of the posterior rectus release (Fig.

72-34).134 Once the lateral aspect of the posterior rectus space has been developed, the posterior rectus

sheath is incised just medial to the neurovascular bundles penetrating the rectus muscle so that they are

not damaged (Fig. 72-35). This procedure should start cranial to the umbilicus which will then expose

the underlying transversus abdominis muscle which is then incised along its medial edge: starting this

dissection caudal to the umbilicus will lead to more difficulty getting into the appropriate plane because

the transversus abdominis muscle has no muscle fibers in this region This step allows entrance into

plane between transversalis fascia/peritoneum and the transversus abdominis muscle (Fig. 72-36).

Figure 72-33. Component separation technique.

The dissection can then be extended laterally to the psoas muscle. The dissection plane can be

extended cephalad to the diaphragm by dissecting dorsal to the sternum, sweeping the

peritoneum/transversalis fascia off the diaphragm. Inferiorly, the dissection can be extended into the

space of Retzius to expose the symphysis pubis and Cooper ligament. This dissection results not only in

the creation of a large retromuscular space beyond the linea semilunaris but also allows for significant

medial advancement of the posterior rectus sheaths which are then closed in the midline followed by

placement of mesh in retromuscular plane and fixation with transabdominal sutures and possibly bone

anchors. The anterior sheaths can then be reapproximated in the midline because the transverse

abdominus release allows further medialization of the anterior sheaths or the gap can be bridged with

mesh. This technique is an important addition in the armamentarium of surgeons dealing with complex

abdominal wall problems and has been shown to have favorable perioperative morbidity and acceptable

recurrence rates compared to anterior component separation.121 The technique is particularly suited for

addressing recurrent hernias after a prior anterior component separation but probably should not be

used simultaneously in combination with a concurrent anterior component separation. However,

posterior component separation is technically difficult because the transversalis fascia/peritoneum

complex posteriorly can be extremely thin, tearing easily. In order to isolate the viscera from the

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prosthetic which will eventually be placed, these tears must be repaired. If this is not possible, one of

the adhesion barrier prostheses should be used. A much easier dissection can be accomplished by not

dividing the transversus abdominis muscle while continuing laterally in the plane between the

transversus abdominis muscle and the internal oblique muscle.135 But, this theoretically should

denervate the muscle because the intercostal nerves travel to the rectus muscle in this plane (see

anatomy section). This remains a controversial issue because another component separation technique

known as the Memphis modification completely detaches the rectus muscle out of its bed after an

external oblique release leaving only the cranial and caudal attachments intact in a manner similar to a

tram flap.136 This technique allows for a completely tension-free reapproximation of the rectus muscles

in the midline. Because the authors do not report an excessive rate of either rectus atrophy or

abdominal wall dysfunction, one must assume that the nerve supply accompanying the inferior and

superior epigastric vessels is sufficient. In addition, this technique is probably best suited for patients

who are not hernia formers but require medialization of the fascial gap after trauma.

Figure 72-34. The retromuscular space is developed by incising the posterior rectus sheath and dissecting the rectus abdominis

muscle from the underlying rectus sheath.

Endoscopic Component Separation. This technique was developed to lessen the degree of abdominal

dissection and potentially address the wound complications associated with open component separation

with the use of a balloon dissector and laparoscopic instruments. The technique involves making 2- to 4-

cm incisions just below the costal margin in anterior axillary line (lateral to the attachment of the

external oblique aponeurosis on the rectus sheath). The space between the external and internal oblique

muscles is dissected and under camera guidance, dissector balloon is inflated which further aids blunt

dissection in this layer. The external oblique aponeurosis is then divided. A Balloon dissector can be

used in the subcutaneous space as well. This technique can be followed by either open or laparoscopic

hernia repair.137,138 One potential limitation might be the adequacy of the myofascial advancements

using this technique. Proponents of this technique claim reduction in postoperative stay by about 50%

and a distinct advantage in the setting of stomas, but it remains to be seen if it is effective in the long

term (Fig. 72-32).

Figure 72-35. The posterior rectus sheath is incised about 0.5 to 1 cm medial to the anterior/posterior rectus sheath junction to

expose the underlying transversus abdominis muscle. Note the perforator nerves that are preserved during retromuscular dissection

and subsequent posterior component release.

Figure 72-36. Division of the posterior rectus fascia just medial to the linea semilunaris and perforator nerves followed by

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division/release of the transversus abdominis muscle along its entire medial edge.

Prosthetic Repairs

The concept of prosthetic use is not new as it was proposed by Usher and colleagues in 1958 for hernia

repair using a polypropylene mesh.139 Over the ensuing years, lessons have been learnt: (a) the use of

absorbable mesh leads to a high relapse rate, (b) repetition of a previously inadequate technique

frequently fails, (c) a simple inlay technique that bridges the defect has a high failure rate, (d)

reinforcement of the entire scar is advisable irrespective of operative findings, and (e) the success of a

mesh repair depends on the extent of overlap or underlap.140

Numerous techniques for prosthetic incisional hernia repair have been described, which is not

surprising since there are so many variables. For example, there are five potential spaces to place the

prosthesis (Figs. 72-3 and 72-37).

Because of the number of different repairs, it is not practical to describe each one in detail. However,

most of them represent a variation of one of the general classes described.

Onlay Prosthetic Technique. The basis of this procedure is to place a prosthesis over any of a wide

variety of simple repairs. Although it has some proponents, many surgeons feel that this technique

offers little advantage over the simple repair that the prosthesis overlies. This may be explained by

Pascal’s law which states that pressure exerted on an enclosed fluid acts equally in all directions. In an

onlay technique, this results in lifting forces against the mesh.141

Figure 72-37. Potential spaces in the abdominal wall to place prosthetic material: onlay or on top of the anterior abdominal

fascia; under the anterior fascia but in front of the muscle (if the mesh bridges that space, it would be an inlay technique);

retrorectus space or the underlay technique below the muscle but above the posterior fascia; preperitoneal (important when below

the arcuate line); intraperitoneal.

Figure 72-38. 1: Hernia defect with bulging sac. 2: Anterior fascia is incised longitudinally on either side of the defect. 3: The

anterior fascia is then rotated medially, in effect lengthening the posterior sheath to allow primary closure, isolating the abdominal

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contents from the anterior fascia. 4: Prosthetic material is used to bridge the anterior fascia.

Prosthetic Bridging Technique. A prosthetic bridging repair became popular in the 1990s in keeping

with the tension-free concept for inguinal herniorrhaphy. The basic principle underlying this technique

is that for a prosthetic repair to be effective, the defect should be bridged. Although this repair is

theoretically attractive, it has not been nearly as successful for incisional hernias as for inguinal hernias.

The recurrence rate is especially high in obese patients. It is not recommended but may be the last

resort if the defect is so large that abdominal wall closure cannot be obtained even with sophisticated

techniques such as component separation. One modification technique used for massive abdominal

hernias is known as medialization which consists of closure of the abdominal wall with ePTFE followed

by scheduled serial visits to the operating room to tighten the prosthesis by removing a strip in the

middle and suturing the edges together. This technique allows definitive abdominal wall closure after a

mean six serial visits.142

Combined Fascia and Mesh Closure. This group of repairs combines features of the component

separation technique (described below) with the tension-free concept. By incising the anterior fascia and

rotating the medial edge toward the midline in continuity with the posterior fascia, the posterior fascia

is effectively lengthened (Fig. 72-38). The posterior fascia is closed primarily, but the anterior fascia is

bridged with a prosthesis.

Sublay Prosthetic Technique. The sublay prosthetic repair, sometimes referred to as the

retromuscular approach, is characterized by the placement of a large prosthesis in the space between the

abdominal muscles and the peritoneum (Fig. 72-17). It was popularized by Rives, Velamenta, Stoppa,

and Wantz and is particularly suitable for large and multiply recurrent hernias when most of the

abdominal wall must be reconstructed.124,143,144 It is considered the most effective conventional

incisional hernia repair and therefore the one against which other procedures must be measured. Its

major disadvantage is its need for wide undermining of the abdominal layers with the potential risk of

devascularization of the abdominal wall or the creation of a large seroma, which later leads to infection.

Suction drains are used by most surgeons, although the literature does not unequivocally support their

use.145

Figure 72-39. Perforating blood vessels supplying the rectus muscle.

The procedure is begun by excising the previous scar and dissecting the peritoneal sac of the hernia to

the level of the fascia. Occasionally, the sac does not have to be opened and the procedure can be

performed totally extraperitoneal. More commonly, the sac is thin and easily disrupted, making

entrance into the peritoneal cavity inevitable. The posterior rectus sheath is opened on each edge of the

hernia defect and dissected away from the undersurface of the recti to the lateral edge of the rectus

sheath, with care being taken to prevent damage to the perforating blood vessels at the lateral side of

the sheath (Fig. 72-39). The posterior rectus sheaths are then approximated to each other primarily

(unless the peritoneum has not been opened). During this part of the procedure, flaps must be created

by dissecting the skin and subcutaneous tissue off the underlying fascia laterally until enough tension is

relieved to allow primary closure of the anterior rectus sheath. It is sometimes necessary to add

component separation to further decrease the tension. A large mesh prosthesis (combined with ePTFE or

an adhesion barrier if the approximation of the posterior rectus sheath is inadequate) is then placed in

this space outside the repaired posterior sheath but beneath the recti. The mesh is secured in this

position with several sutures directly to the posterior rectus sheath. An alternative is to use a suture

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