You are in: eMedicine Specialties > Plastic Surgery > TRUNK Abdominal Wall ReconstructionArticle Last Updated: Jul 18, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 11
  Author: Mark A Grevious, MD, FACS, Assistant Professor of Surgery, Associate Program Director, Division of Plastic and Reconstructive Surgery, University of Illinois at Chicago Mark A Grevious is a member of the following medical societies: American College of Surgeons, American Society of Maxillofacial Surgeons, American Society of Plastic Surgeons, and Association for Academic Surgery Coauthor(s): Mimis Cohen, MD, FACS, FAAP, Professor and Chief, Division of Plastic, Reconstructive and Cosmetic Surgery, University of Illinois at Chicago; Consulting Staff Craniofacial Center, University of Illinois at Chicago; Aisha D White, MBA, MD, Staff Physician, Department of Plastic Surgery, University of Illinois at Chicago; Bradon J Wilhelmi, MD, Endowed Leonard Weiner, MD, Professor and Chief of Division of Plastic Surgery, Residency Program Director, University of Louisville School of Medicine Editors: Dennis P Orgill, MD, PhD, Associate Professor, Harvard Medical School; Director, Burn Center, Brigham and Women's Hospital; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; R Edward Newsome, MD, Associate Professor, Program Director and Chief, Department of Surgery, Section of Plastic Surgery, Tulane University Health Sciences Center; Nicolas (Nick) G Slenkovich, MD, Practice Director, Colorado Plastic Surgery Center at Swedish Medical Center; Jorge I de la Torre, MD, FACS, Professor of Surgery and Physical Medicine and Rehabilitation, Residency Program Director, Division of Plastic Surgery, University of Alabama at Birmingham; Director, Center for Advanced Surgical Aesthetics Author and Editor Disclosure Synonyms and related keywords: abdominal wall reconstruction, abdominal reconstruction, abdominal defect, abdominal wall defect, tissue rearrangement, regional flap, free tissue transfer, abdominal layer, abdominal wall, abdominal procedure, abdomen defect, abdominal wall function, ventral hernia repair, ventral defect, abdominal viscera herniation, hernia, hernia reconstruction, incisional hernia, celiotomy, intraabdominal pressure, herniorrhaphies, desmoid tumor, abdominal tumor, abdominal gunshot injury, abdominal gunshot INTRODUCTIONSection 2 of 11
  The management of complex abdominal wall defects has been perplexing to both general surgeons and reconstructive surgeons since the turn of the last century. The goals of the reconstructive surgeon in managing complex abdominal wall defects are to restore the structural and functional continuity of the musculofascial system and to provide stable and durable wound coverage. The criterion standard of tissue selection for abdominal wall reconstruction is autologous tissue, which includes the use of adjacent tissue rearrangement techniques, regional flaps, and, occasionally, free tissue transfer. Reconstruction of the structural components of the abdominal wall is important, but even more important is the restoration of abdominal wall function. This concept is demonstrated in the components separation technique for ventral hernia repair, first reported by Ramirez and colleagues.1 This technique uses musculofascial components of the abdominal wall in continuity with their vascular and nerve supply to reconstruct ventral defects. A thorough understanding of structural and functional anatomy of the abdominal wall is essential to achieve a successful reconstruction. INDICATIONSSection 3 of 11
Indications for abdominal wall reconstruction include defects caused by trauma, tumor extirpation, multiple previous abdominal procedures, and, occasionally, infection. Recently, with the great success of small bowel transplantation in infants with short gut syndrome, abdominal wall reconstructive principles have been employed to accommodate the small bowel from a living related adult into the abdominal cavity of an infant. Abdominal wall defects of any size may allow herniation of the abdominal viscera, which can lead to incarceration and, ultimately, strangulation. However, larger abdominal wall defects usually do not pose a threat of incarceration. The rate of incisional hernia following celiotomy ranges from 3-20%. Factors associated with the formation of an incisional hernia include wound infection, immunosuppression, morbid obesity, previous operations, patient age, and medical conditions (eg, prostatism) that may cause an increase in intra-abdominal pressure postoperatively. Direct primary closure involves direct suture apposition of healthy strong fascial tissue on each side of the defect. However, recurrence rates after this procedure range from 41-52% during long-term follow-up. Herniorrhaphies in which large prosthetic meshes are implanted appear to have lower failure rates (12-4%). Transverse incisions course parallel to the relaxed skin tension lines of the abdominal wall and tend to heal as thinner, flatter scars, as less tension is present on these wounds.2, 3, 4 Additionally, transverse incisions have the lowest rate of herniation compared to midline and paramedian incisions.5 The reason for this is that lateral traction of the external oblique, internal oblique, transversus abdominis, and rectus abdominis muscles places tension on the fascia at the linea alba and on the skin to increase risk of skin and fascial dehiscence. Increased intra-abdominal pressure, as observed with chronic lung disease, coughing, or ascites, can also contribute to the risk of incisional hernia. The authors have also found that the rate of hernia recurrence following repair is markedly reduced in patients who have transverse abdominal wall defects, even when prosthetic or bioprosthetic material has been used. Of the various tumors that develop on the abdominal wall, desmoid tumors are the most common benign tumors. These lesions are histologically benign but locally invasive. Treatment consists of full-thickness abdominal wall resection. Methods for reconstruction of such defects include musculocutaneous flap reconstruction or the use of prosthetic or bioprosthetic material. For more detail, please see Media files 1-4 below. Local recurrence remains approximately 40% and usually occurs within 2 years, despite aggressive treatment. Adjuvant radiotherapy may be required when margins are inadequate. Treatment of malignant tumors of the abdominal wall requires aggressive resection of involved skin and subcutaneous tissue as well as the myofascial component, if it is violated by the tumor. Sarcomas are the most common and require both aggressive resection and radiotherapy. Intra-abdominal tumors can also involve the abdominal wall, either from contiguous or hematogenous spread. Reconstruction of the abdominal wall in these cases is usually directed by the extent of resection and the possibility of further surgical intervention. Abdominal wall defects associated with traumatic abdominal injuries are commonly a result of gunshot injury. These abdominal wounds may be grossly contaminated from simultaneous bowel injuries and require delayed reconstruction in multiple stages. Abdominal wall soft tissue infections are rare except as a complication of a prior mesh repair of abdominal fascia. However, cases of necrotizing fasciitis following inadvertent bowel injury during abdominal liposuction have been reported. Abdominal wall mesh infections commonly present as draining sinuses over the abdomen. Mesh infections are resistant to wound care and antibiotics. Often, successful treatment of the abdominal infection requires removal of the infected mesh and staged abdominal reconstruction. Patient selection is also crucial. Performing a technically sound operation on a patient with multiple comorbidities may result in an outcome that is less than optimal. For a discussion of patient selection and preoperative considerations, see Preoperative considerations. RELEVANT ANATOMYSection 4 of 11
The anatomical layers of the abdominal wall include skin, subcutaneous tissue, superficial fascia, deep fascia, muscle, extraperitoneal fascia, and peritoneum. This anatomy may vary with respect to the different topographic regions of the abdomen. The major source of structural integrity and strength of the abdominal wall is provided by the musculofascial layer. The main paired abdominal muscles include the external oblique muscles, internal oblique muscles, transversus abdominis muscles, and rectus abdominis muscles and their respective aponeuroses, which are interdigitated with each other, and provide core strength and protection to the abdominal wall viscera. The integrity of the abdominal wall is essential not only to protect the visceral structures but also to stabilize the trunk and to aid trunk movement and posture.
Early 19th century anatomist August Rauber described the large gap in the skeletal system between the lower edges of the thorax and the upper edge of the pelvis as the lacuna sceleti sterno-pubica. This gap is closed by the abdominal muscles and their aponeuroses. The skeletal system, which is relatively fixed, provides attachment points for the soft tissue and muscles of the abdominal wall. The skeletal anatomy of the abdomen consists of the xiphoid process, the costal cartilages of ribs 7-10, the floating ribs 11 and 12, the L1-L5 vertebrae, the iliac crests, the anterior superior iliac spine, the pubic tubercle/pubic crest, and the pubic symphysis. The abdominal wall musculoaponeurotic structure is attached to the ribs superiorly, the bones of the pelvis inferiorly, and the vertebral column posteriorly. Subcutaneous TissueSuperficial fascia Deep fascia The deep fascia is a thin, tough layer that surrounds and is adherent to the underlying abdominal muscles. Each abdominal muscle has an aponeurotic component that contributes to the deep fascia. The individual abdominal muscles are described below. Subserous and peritoneal fascia The subserous fascia is also known as extraperitoneal fascia and serves to bond the peritoneum to the deep fascia of the abdominal wall or to the outer lining of the gastrointestinal tract. It may receive different names depending on its location (ie, transversalis fascia when it is deep to that muscle, psoas fascia when it is next to that muscle, iliac fascia, and so on). The peritoneum is a thin (one cell thick) membrane that lines the abdominal cavity. It is useful in reconstructive efforts because it provides a layer between the bowel and mesh. Also, studies have exemplified the utility of the thin, pliable, peritoneal-lined rectus flap in vaginal wall reconstructions. Musculofascial layer The abdominal wall includes 5 paired muscles (3 flat muscles, 2 vertical muscles). The 3 flat muscles are the external oblique, internal oblique, and transversus abdominis. The 3-layered structure, combined with extensive aponeuroses, works in a synkinetic fashion not only to protect the abdominal viscera but also to increase abdominal pressure, which facilitates defecation, micturition, and parturition. The 2 vertical muscles are the rectus abdominis and pyramidalis. Fusion of the fascial layers of these muscles forms 3 distinct fascial lines: the linea alba and 2 semilunar lines. The linea alba is formed by the fusion of both rectus sheaths at the midline, while the semilunar lines are formed by the union of the external oblique, internal oblique, and transversus abdominis aponeuroses at the lateral border of the rectus abdominis muscle. External oblique The external oblique muscle is the largest and thickest of the flat abdominal wall muscles. It originates from the lower 8 ribs, interlocks with slips of latissimus dorsi and serratus anterior, and courses inferior-medially, attaching via its aponeurosis centrally at the linea alba. Inferiorly, the external oblique aponeurosis folds back upon itself and forms the inguinal ligament between the anterior superior iliac spine and the pubic tubercle. Medial to the pubic tubercle, the external oblique aponeurosis is attached to the pubic crest. Traveling superior to the medial part of the inguinal ligament, an opening in the aponeurosis forms the superficial inguinal ring. The innervation to the external oblique is derived from the lower 6 thoracic anterior primary rami and the first and second lumbar anterior primary rami. Internal oblique The internal oblique muscle originates from the anterior portion of the iliac crest, lateral half to two-thirds of the inguinal ligament, and posterior aponeurosis of the transversus abdominis muscle. The internal oblique fibers run superior-anteriorly at right angles to the external oblique and insert on the cartilages of the lower 4 ribs. The anterior fibers become aponeurotic at around the ninth costal cartilage. At the lateral border of the rectus abdominis muscle and above the arcuate line, the aponeurosis splits anteriorly and posteriorly to enclose the rectus muscle to help form the rectus sheaths. However beneath the arcuate line, the internal oblique aponeurosis does not split, resulting in an absent posterior rectus sheath. The inferior aponeurotic fibers arch over the spermatic cord, pass through the inguinal canal and then descend posterior to the superficial ring to attach to the pubic crest. The most inferior medial tendinous fibers fuse with the aponeurotic fibers of the transversus abdominis muscle to form the conjoint tendon, which also inserts on the pubic crest. Transversus abdominis The transversus abdominis muscle is the innermost of the 3 flat abdominal muscles. The fibers of the transversus abdominis course predominately in a horizontal orientation. It has 2 fleshy origins and 1 aponeurotic origin. The first fleshy origin is from the anterior three-fourths of the iliac crest and lateral third of the inguinal ligament, while the second origin is from the inner surface of the lower 6 costal cartilages where they interdigitate with fibers of the diaphragm. Between the 2 fleshy origins is the aponeurotic origin from the transverse processes of the lumbar vertebrae. These fibers course medially to the lateral border of the rectus muscle. From about 6.6 cm inferior to the xiphoid process to the arcuate line, the insertion is aponeurotic and contributes to the formation of the posterior rectus sheath. Rectus abdominis The rectus abdominis muscles are paired, long, straplike muscles that are the principal vertical muscles of the anterior abdominal wall. The rectus abdominis is interrupted throughout its length by 3-4 tendinous inscriptions, all of which are adherent to the anterior rectus sheath and separated by the linea alba. These inscriptions can be visualized externally in a well-developed individual secondary to fasciocutaneous ligaments. The medial tendon of the rectus abdominis originates from the pubic symphysis and the lateral tendon of the rectus abdominis originates from the pubic crest. It inserts to the anterior surfaces of the fifth, sixth, and seventh costal cartilages and xiphoid process. The lateral border of each rectus muscle and its sheath merge with the aponeurosis of the external oblique to form the linea semilunaris. The rectus abdominis muscle functions as a tensor of the abdominal wall and flexor of the vertebrae. Additionally, this muscle helps to stabilize the pelvis during walking, protects the abdominal viscera, and aids in forced expiration. The rectus sheath is a strong, semifibrous compartment that houses the rectus muscles, the superior and inferior epigastric vessels, and the inferior 5 intercostal and subcostal nerves. It is formed by interlacing aponeurotic fibers from the 3 flat abdominal muscles. The anterior rectus sheath is the union of the external oblique aponeurosis and the anterior layer of the internal oblique. The posterior rectus sheath is composed of the posterior layer of the internal oblique aponeurosis, the transversus abdominis aponeurosis, and the transversalis fascia. Pyramidalis The pyramidalis is a small triangular muscle located anterior to the inferior aspect of the rectus abdominis; the pyramidalis is absent in about 20% of the population. The pyramidalis originates from the body of the pubis directly inferior to the insertion of the rectus abdominis and inserts into the linea alba inferior to the umbilicus to assist in stabilization of the lower midline. Arcuate line Linea alba The linea alba is the fusion of the anterior and posterior rectus fascia; it is located in the abdominal midline, between the rectus muscles, from the xiphoid to the pubis. The linea alba is a 3-dimensional composition of tendon fibers from abdominal wall muscles. Midline insertions of these fibers play a significant role in stabilizing the abdominal wall. The cranial aspect is attached to the xiphoid process, while, caudally, it inserts at the pubic symphysis. Linea semilunaris The linea semilunares can be seen as a pair of linear impressions in the skin that correspond with the most lateral edges of the rectus abdominis. These lines are visible in a person who is physically fit but obscured in a person who is obese. They are formed by the band of aponeuroses of the external oblique, the internal oblique, and the transversus abdominis muscles.
The plane between the internal oblique muscle and transversus abdominis muscle contains the neurovascular structures that supply the abdominal muscles. The superior and inferior deep epigastric vessels enter the rectus muscle superiorly and inferiorly. Transperitoneal vessels enter the rectus in the periumbilical region. The abdominal wall receives its blood supply from direct cutaneous vessels and musculocutaneous perforating vessels.6 The 2 subdivisions of perforators course medially and laterally. The lateral branch is usually the dominant branch and contains most of the perforator vessels.7 The lateral fasciocutaneous perforators pierce the aponeuroses of the internal and external oblique muscles. They may pass through the linea alba and emerge on the lateral aspect of the rectus abdominis.7 El-Mrakby et al performed microdissections to analyze the vascular anatomy of the anterior abdominal wall. They concluded that the musculocutaneous perforators are the main providers of blood supply to the anterior abdominal wall.8 Also, the vessels were further categorized into large (direct) or small (indirect) perforators. The indirect perforators generally have diameters less than 0.5 mm and terminate in the deep layer of the subcutaneous fat.8 Conversely, the direct perforators have diameters greater than 0.5 mm and course into the subdermal plexus to supply the superficial subcutaneous fat and skin.8 In addition, El-Mrakby et al described the area lateral and inferior to the umbilicus as the area with the richest concentration of perforator vessels.8 This vascular network allows multiple flap designs that may incorporate one or several perforator vessels. A study by Huger et al classified the vascular blood supply of the abdominal wall into 3 simple zones for abdominoplasty.9 Zone I is defined by the mid abdomen and is supplied primarily by the deep epigastric arcade. As the internal thoracic artery passes behind the costal cartilages to enter the abdominal wall, it gives rise to the superior epigastric artery. This vessel then enters the abdomen and travels underneath the surface of the posterior rectus sheath. The superior epigastric artery joins the deep inferior epigastric artery through a series of choke vessels within the rectus above the umbilicus. Zone II is defined by the lower abdomen and is supplied by branches of the epigastric arcade and the external iliac artery. Blood supply superficial to the fascia is provided by the superficial epigastric and superficial pudendal arteries. Both of these arteries originate from the femoral artery. The deep iliac circumflex artery originates from the external iliac and runs deep to all abdominal muscles to provide blood supply to the area of the anterior iliac spine; it also pierces all 3 muscles of the lateral abdominal wall and provides a sizable musculocutaneous perforator. Zone III comprises the flanks and lateral abdomen. Blood supply to this area comes from the intercostal, subcostal, and lumbar arteries. The intercostal vessels leave the rib cage and enter the abdominal wall between the transversus abdominis and internal oblique muscles, where they anastomose with the lateral branches of the superior epigastric artery and deep inferior epigastric artery. Sensory innervation to the abdomen is derived from the roots of the nerves T7 to L4. These nerves travel in the plane between the internal oblique and transversus abdominis muscles. Motor innervation is provided by the intercostal, subcostal, iliohypogastric, and ilioinguinal nerves. These nerves must be preserved during abdominal wall reconstruction in order to maintain abdominal wall sensation and muscular function. CONTRAINDICATIONSSection 5 of 11
As stated above, patients with significant comorbidity and low potential benefit of hernia repair are poor candidates for abdominal wall reconstruction. Patients with conditions such as chronic obstructive pulmonary disease (COPD), heart disease, and liver failure must be preoperatively screened. Postoperatively, patients with COPD may be difficult or impossible to wean from the ventilator. Intra-abdominal operations involve large fluid shifts and place a significant stress on the heart intraoperatively and postoperatively, with intravascular return of third space volume (ie, on postoperative day 3). In addition, patients with liver failure have high morbidity and mortality rates with operations that require general anesthesia and should not undergo elective abdominal wall reconstruction. The risk of such a major operation for patients with the above comorbid conditions must be defined, as these risks almost always outweigh the benefit of abdominal wall reconstruction. Other relative contraindications to elective abdominal wall reconstruction/ventral hernia repair include preexisting conditions that may increase the risk of recurrence (ie, smoking, mild COPD, obesity, diabetes, ascites, cancer, multiple hernia recurrences, a noncompliant patient). For more information on these conditions, visit the following Medscape Resource Centers: Smoking, COPD, Diabetes, Hernia. TREATMENTSection 6 of 11
Preoperative DetailsPreoperative preparation Preoperative preparation for abdominal wall reconstruction, as with any other surgical procedure, involves a thorough patient history and physical examination. Appropriate laboratory studies should be reviewed, as well as chest radiographs and ECG for patients older than 35 years. Furthermore, patients with a history of pulmonary problems such as COPD should undergo pulmonary function tests and a baseline arterial blood gas analysis. Patients with a history of diabetes or chest pain should undergo an appropriate cardiac risk evaluation with echocardiogram and stress test. Once the decision has been made to proceed with operative intervention, the patient should receive a bowel preparation in case of enterotomy. Patients also should receive prophylactic antibiotics and deep venous thrombosis prophylaxis. Preoperative considerationsPrior to any operative intervention, a thorough evaluation is essential. A proper diagnosis must first be made by evaluating the anatomy and by defining the extent of the defect and understanding which anatomical structures are present or absent. Patient selection is also crucial. Performing a technically sound operation on a patient with multiple comorbidities may result in an outcome that is less than optimal. Comorbidities such as diabetes, poor nutrition, and obesity may also be detrimental to the surgical outcome. If in question, preoperative respiratory function should be assessed as reconstruction of the abdominal wall can compromise vital capacity. Patients with actively infected wounds and/or systemic infections are poor candidates for reconstruction with prosthetic materials. Some of the most important concepts that a surgeon should consider prior to embarking on an abdominal wall reconstructive procedure with prosthetic materials include the following:
The timing of reconstruction depends on several factors. Bowel edema, gross contamination, or patient instability may preclude definitive abdominal wall reconstruction. Wound preparation and control of infection are two key principles for successful reconstruction of the abdominal wall. If a patient has a contaminated wound with necrotic tissue present, irrigation and debridement should be the first line of therapy. Once adequate debridement is performed, wound coverage with occlusive dressings, vacuum-assisted wound closure (VAC) devices, absorbable prosthetic material, or a prosthetic patch may be used as a temporizing solution. This method of delayed wound coverage allows for stabilization of the patient until definitive reconstruction can be performed. Reconstructive options for abdominal wall repair are vast and the complication rates can be high; therefore, preoperative planning is of critical importance. The size and location of skin and fascial defects must be determined by either examination or CT scan. Small skin defects can usually be repaired by direct approximation after extensive undermining of the skin from underlying tissues. If a sizable skin defect is present (eg, after resection of a tumor or skin loss with trauma), staged tissue expansion, fasciocutaneous flap, or myocutaneous flap is required. The location of the skin defect influences flap selection (discussed below). Moderately sized fascial defects can sometimes be repaired primarily but may require reconstruction with the components separation technique. The components separation technique involves the release of 2 separate components as follows:
The components separation technique provides midline fascial advancement of 10 cm at the epigastrium, 20 cm at the waistline, and 6 cm in the suprapubic area when separated bilaterally.1 Thus, the applicability of the components separation technique depends on the size and location of the fascial deficit. When treating large fascial defects, the components separation technique may not be suitable. Consider other options, such as prosthetic mesh, nonvascularized fascial graft, myocutaneous fascial flap (tensor fascia lata [TFL]), and tissue expansion of fascia.10 If adequate skin is available to close over the fascial repair, the first choice for repair of a fascial defect is prosthetic mesh. The main advantage of prosthetic mesh for fascial repair is that using a larger piece of mesh avoids the dramatic increase in intra-abdominal pressure often observed with hernia repairs. This pressure can result in decreased functional residual capacity, difficulty in weaning patients from ventilators, and increased risk of hernia recurrence. The existence of prosthetic mesh infection may require explantation of the mesh and autogenous reconstruction, even the consideration of staged reconstruction, depending on the extent of the infection. Staged reconstruction involves temporarily approximating the fascia with absorbable Vicryl mesh to minimize the fascial defect, which eventually requires permanent reconstruction. Intraoperative detailsGrafts Grafts can be used in reconstructing the fascia when ample overlying skin and subcutaneous tissue are present. Autogenous fascial grafts have been used to repair abdominal fascial defects. Several prosthetic grafts have been successfully used for abdominal fascial repair, including polypropylene (Prolene [Ethicon, Piscataway, NJ], Marlex [ConocoPhillips, Houston, Tex]), polyethylene (Dacron [DuPont, Wilmington, Del]), polytetrafluoroethylene (PTFE [DuPont, Wilmington, Del], Gore-Tex [WL Gore & Associates, Newark, Del]), polyester (Mersilene [Ethicon, Piscataway, NJ]), polyglactin (Vicryl [Ethicon, Somerville, NJ], Dexon [Syneture, Norwalk, Conn]), and autogenous nonvascularized fascial grafts. Prosthetics When autologous tissue is not available for the reconstruction because of tissue loss, loss of domain, or other reasons, the use of prosthetics or bioprosthetics is required to assist in the reconstruction of the abdominal wall. Biomaterials are also used in the temporary coverage of these difficult soft tissue defects. Some of the advantages of using prosthetic materials include availability, absence of donor site morbidity, and strength of the prosthetic material. Obvious disadvantages are susceptibility to infection (which may necessitate explantation), fistula formation secondary to bowel erosion, extrusion, and seroma formation. No "one mesh fits all" concept exists in abdominal wall reconstruction; thus, in efforts to address this surgical conundrum, numerous synthetic materials have been designed to facilitate closure of these defects. Many different types of prosthetic and bioprosthetic materials are currently available, and even more products are being brought to the marketplace. Each new product that is introduced is heralded as the next new and improved biomaterial. Navigating through all of these new products can be difficult, especially without long-term clinical and experimental data to support their use. Therefore, a thorough understanding of each prosthetic material, its cost, its applications, its contraindications, and its incidence of complications, as well as the management of these complications, is of paramount importance. Polypropylene is probably the most commonly used synthetic prosthetic material for abdominal fascial repair. It has large pores that induce fibrovascular incorporation. Polypropylene is most suitable for clean wounds with adequate soft tissue coverage. Occasionally, polypropylene mesh granulates over and allows for grafting; this occurs less commonly with polytetrafluoroethylene mesh. There are expected disadvantages with polypropylene, as with any prosthetic material. The direct intraperitoneal placement of polypropylene material onto uncovered bowel can cause bowel erosion into the soft tissue, resulting in enterocutaneous fistulas. Furthermore, the material can erode through skin leading to extrusion of the prosthetic material. While more resistant to infection than some other prosthetic material, polypropylene is susceptible to infection. Polytetrafluoroethylene (PTFE, Gore-Tex) mesh has unique physical properties; it is not water absorbent and is resistant to adherence. Initial studies in animal models revealed no acute host inflammatory reaction to the material[30]. However, because of the lack of fibrovascular incorporation of this material, it becomes infected easily and has been noted to have a high complication rate. However, Bauer et al, in 1987, reported their experience with PTFE abdominal repairs in 28 patients with only 3 hernia recurrences (10.7%).14 Another concerning and frequent complication with the use of PTFE for abdominal hernia repair is seroma formation. Polyglactin 910 (Vicryl) has been found to be inert, nonantigenic, and nonpyrogenic. It has a high tensile strength with material retention of 60% at day 7, 35% at day 14, and only 5% at day 28. Polyglycolic acid is completely hydrolyzed in 90-120 days. Vicryl mesh is a tightly-woven broadcloth that is thick and flexible, though not elastic. In a contaminated operative field, placement of absorbable prosthetic material provides temporary coverage and abdominal wall support until wound contamination resolves. Absorbable material is often utilized in staged-reconstructive procedures. Split-thickness skin graft (STSG) can be placed directly on the granulated base of this prosthetic material for temporary closure. Subsequent hernia formation is expected after the absorption of the prosthetic material. Composite mesh material The complications seen with traditional prosthetic materials have led to the development of composite products that combine absorbable with nonabsorbable materials or nonabsorbable materials with tissue-separating barrier materials. Numerous composite products are available today, including Composix (Duval, Inc., Bioprosthetics Abdominal wall reconstruction with bioprosthetic material has gained wide popularity over the past several years. The reasons for this paradigm shift are the touted desirable properties of this material, which include the following:
Tissue expansion Tissue expansion has been extensively used to recruit skin and soft tissue to cover fascial repairs with mesh.15, 16 Tissue expansion has been described for expansion of fascia in the treatment of abdominal wall reconstruction;10, 17 however, this application is not commonly performed. Using tissue expansion for abdominal wall reconstruction has several advantages, including color match, contour match, and minimal donor deformity. However, tissue expansion requires at least one extra operation and possibly more, if a complication such as expander extrusion occurs. Myocutaneous flaps can provide skin, soft tissue, and fascia in the reconstruction of full-thickness abdominal wall defects. Myocutaneous flaps are also the preferred reconstructive option in contaminated wounds for which nonabsorbable prosthetic mesh cannot be safely used. Furthermore, myocutaneous flaps are used to reconstruct clean wounds after tumor resection to provide skin and soft tissue coverage over fascial repairs with mesh. The rectus abdominis muscle is the workhorse in abdominal wall reconstruction. The rectus abdominis can be used with or without a skin paddle to reconstruct wounds in the upper and lower quadrants of the abdomen as well as the suprapubic and umbilical area.18 The only area in which this flap is less suitable is the epigastrium. The rectus abdominis muscle can be based cephalically on the deep superior epigastric artery or caudally on the deep inferior epigastric artery. The rectus muscle averages 25 X 6 cm and can provide large transverse or vertical skin components. The TFL flap is the next option for reconstruction of the umbilical, suprapubic, and lower quadrant abdominal areas.18 The TFL flap is a myocutaneous flap based on the lateral femoral circumflex artery. The TFL muscle is 13 cm long, 3 cm wide, and 2 cm thick. The TFL muscle originates from the anterior superior iliac spine (ASIS) and the iliac crest and inserts into the iliotibial tract. The skin paddle is harvested 10 cm in width and designed over the muscle along an axis from the ASIS to the lateral tibial condyle. The inferior limit of the cutaneous territory can be extended to 6 cm above the knee and 25-35 cm in length. The lateral femoral circumflex artery can be found approximately 6-8 cm inferior to the ASIS. The flap can be made to be sensate by designing it to include the T12 dermatome; this is done by fashioning the flap to include the area 6 cm posterior to the ASIS.19 The rotation arc of the pedicled flap reaches the costal margin if the tensor muscle is completely detached from its origin and raised as an island flap. However, the TFL flap is not useful to reconstruct defects of the upper abdomen because the distal third of the skin paddle is less reliable. The rectus femoris can provide muscle and fascial coverage to the lower quadrant, umbilical, suprapubic, and epigastric areas. Dibbell described the mutton chop modification with medial fascial extension to reach this difficult area.20 The rectus femoris muscle originates from the anteroinferior iliac spine and inserts on the patellar tendon. The rectus femoris is supplied by the lateral femoral circumflex vessels entering the muscle 6-8 cm below the anterior superior iliac spine or at the level of the pubic tubercle. A cutaneous paddle of 11 X 30 cm can be reliably harvested with this muscle and still allow primary closure of the donor. The primary function of this muscle is the terminal 20° of knee extension. This flap is easier to dissect than the TFL flap but has been accused of resulting in weak knee extension, which can be avoided by suturing the vastus medialis and lateralis muscles to the cut rectus femoris tendon. Several other muscle flaps have been reported to reconstruct abdominal defects, including the anterolateral thigh; external oblique; and the distally based internal oblique, gracilis, vastus lateralis, and latissimus muscles. Other flaps that have been used to reconstruct abdominal defects include the omentum, thigh, and groin flaps. Vacuum-assisted closure (VAC) therapy The vacuum-assisted closure (VAC) device has really revolutionized the management of wounds over the past decade or so. The VAC has been shown to decrease infection, decrease wound edema, and stimulate neovascularization of the wound bed. Depending on the depth of the wound and the extent of the defect, the wound VAC has been used to accelerate healing by secondary intention and wound preparation prior to reconstruction with flaps and/or grafts. It is frequently used as a bridge between initial wound care and final stage definitive wound closure. The VAC has also been used to treat enterocutaneous fistulas. Enterocutaneous fistulas cause the adjacent wound to be exposed to succus entericus, which contains acids and enteric enzymes that hinder wound healing. The VAC can be used to remove these secretions and promote ingrowth of granulation tissue that, ultimately, contracts and epithelializes but may still need skin grafting. A general surgeon should assist in treating an abdominal wound that communicates with the intestine or colon. Decision tree In determining the appropriate management of abdominal wall hernias and wounds, it seems more deliberate to address elective ventral hernia repairs separate from contaminated/infected/traumatic abdominal wounds and abdominal wounds after tumor resection. Reconstruction of small abdominal wall defects, particularly in an elective setting, can be achieved by using direct primary closure of the fascial edges or by using the components separation technique to achieve a tension "reduced" repair. The overlying skin, if healthy, can be undermined safely to the anterior axillary line to provide adequate soft tissue coverage following myofascial reconstruction. In the case of adequate skin but a large deficit of fascia, the abdominal fascia can be repaired with polypropylene mesh and the skin closed by direct approximation. If a large deficiency of skin and fascia is present, the reconstruction can be performed by regional flap reconstruction, by free tissue flap reconstruction, or by a staged reconstruction with placement of a tissue expander insertion as the first stage and fascial repair with polypropylene mesh and skin repair by direct approximation as the second stage. COMPLICATIONSSection 7 of 11
The list of possible complications to abdominal wall reconstruction is extensive and includes hernia recurrence, infections, dehiscence, donor site complications, ileus, enterotomy, loss of umbilicus, abdominal compartment syndrome, renal failure, respiratory failure, pneumonia, and failure of implanted prosthetic and bioprosthetic materials. FUTURE AND CONTROVERSIESSection 8 of 11
Conclusion The management of complex abdominal wall defects continues to evolve. Successful abdominal wall reconstruction relies on careful perioperative planning, thorough technical execution, close follow-up, and appropriate selection of prosthetic or bioprosthetic material, when indicated. Smaller defects can be reconstructed with local or regional tissue rearrangement procedures. Larger defects of the abdominal wall, which may have resulted from trauma or tumor extirpation, may require the use of myocutaneous flaps, prosthetic or bioprosthetic material, or both. These reconstructions can be performed in either 1 stage or 2 stages. Posttraumatic abdominal wall reconstruction may require a 2-stage reconstruction. The onus continues to fall on the reconstructive surgeon to be well informed about the indications, properties, and complications associated with the use of these very important biomedical tools to improve the quality of the lives of the patients who are being treated for these complex defects. Defect size, location, depth of involvement, contamination, and comorbidity are all considerations that influence the management of abdominal wall defects. As the potential for complications of abdominal wall reconstruction is significant, patients with comorbid conditions must be appropriately evaluated and screened. However, with meticulous planning, application of operative techniques which incorporate the principle of reconstruction with minimal tension, and diligent postoperative care, abdominal wall reconstruction can be achieved with reasonable functional and cosmetic outcomes, patient satisfaction, and acceptable complication rates. ACKNOWLEDGMENTSSection 9 of 11
The authors and editors of eMedicine gratefully acknowledge the contributions of previous authors Michael Neumeister, MD, FRCSC, FACS; Arian Mowlavi, MD; and Elvin G Zook, MD to the development and writing of this article. MULTIMEDIASection 10 of 11
REFERENCESSection 11 of 11
Abdominal Wall Reconstruction excerpt Article Last Updated: Jul 18, 2008 | ||||||||||||||||||||||||||||||||||||||||
