Abdominal wall reconstruction has become a frequently used term to describe hernia repairs that try to recreate the abdominal wall and restore function and structure. Although there has been no true definition of a functional abdominal wall, many surgeons believe this involves the closure of the fascia at the midline often with reinforcement using mesh prosthetics.
The integrity of the abdominal wall is vital as it serves to protect the internal organs, supports the spine and helps maintain an upright posture. Also, the abdominal wall also aids in the performance of several bodily functions that require the generation of Valsalva such as urination, coughing or defecation. There are also suggestions that an absence of an intact abdominal wall can fail to determine satiety, consequently leading to weight gain.
An incisional hernia following exploratory laparotomy occurs in about 5% to 20% of patients. Risk factors for incisional hernia formation include (1) immunosuppression, (2) wound infection, (3) morbid obesity, (4) malnutrition, (5) patient age, (6) prior abdominal surgery, (7) and any medical condition that is associated with an increase in intra-abdominal pressure in the post-operative period. Other biological factors that may increase risk include have a connective tissue disorder like Ehlers-Danlos syndrome, history of the aneurysmal disease, a diet high in chickpeas, or lathyrism.
Several tumors can occur on the abdominal wall, and the most common are desmoid tumors. These lesions even though histologically benign, often are very locally invasive. Treatment of desmoids often requires full thickness abdominal wall excision. Despite this, local recurrence rates are nearly 40% to 50%. Most of these recurrences occur within the first 24 months after surgery. In some cases, adjuvant radiation therapy is recommended especially when the margins are not clear.
Management of malignant lesions of the abdominal wall requires aggressive resection of the subcutaneous tissues and skin, as well as any involved muscle. Sarcomas are the most common tumors of the abdominal wall and require aggressive resection, followed by radiotherapy. There may also be some intraabdominal wall tumors either via hematogenous or contiguous spread that require resection. Reconstruction of the abdominal wall in these cases is usually directed by the extent of resection and the possibility of further surgical intervention.
The abdominal wall comprises several different layers encompassing skin, subcutaneous tissue, fascia, muscle, and peritoneum. Knowledge of the pertinent anatomy including neurovascular anatomy of the abdominal wall is paramount to achieve successful abdominal wall reconstruction.
Indications for reconstruction of the abdominal wall may be structural defects or symptoms, with goals ranging from providing pain relief to prevention of strangulation or incarceration. However, it is important to remember that while the size of the abdominal wall defect can be associated with herniation of abdominal contents, the size of the defect also places them at low risk for incarceration. Abdominal wall defects that eventually require reconstruction include those arising from the removal of cancer, management of severe infections and repair of prior abdominal wounds.
Current absolute contraindications to abdominal wall reconstruction include the inability to tolerate general anesthesia. As abdominal wall reconstruction represents a major abdominal surgery, several considerations and relative contraindications exist. One of the most common risks associated with abdominal wall reconstruction includes that of surgical site infection and occurrences. These often can complicate these procedures and make patients prone to recurrent hernias. Several factors are associated with increased risk of surgical site infection and occurrences and can be modified. Current smoking has been a relative contraindication for abdominal wall construction for many surgeons secondary to the increased risk of surgical site infection, and many surgeons require at least 30 days of smoking cessation before surgery. Morbid obesity and uncontrolled diabetes also can be relative contraindications and surgeons should work with patients to achieve weight loss and control of diabetes before major abdominal wall reconstruction.
Standard equipment for major abdominal surgery is typically required. Mesh prosthetics are also typically required for abdominal wall reconstruction and can be left to the discretion of the surgeons. Surgeons should, however, know about the available mesh prosthetics and their properties including the advantages and disadvantages of each of the categories.
As these cases represent major abdominal surgery, an assistant (either surgical trainee, physician assistant, or scrub technician) is often needed to aid in retraction during surgery.
The patient should be prepared for any other standard abdominal surgery. Preoperative optimization with weight loss and nutrition management, comorbidity management, and smoking cessation should be performed. The patient is placed in supine position with arms tucked and appropriate padding as per any other major abdominal surgery.
To achieve midline fascial closure, especially in larger hernias, often components of the abdominal wall must be separated to allow for tension free repairs. Various component separation techniques have been described and involve cutting muscle and fascial layers of the abdominal wall. The most commonly used component separation, first described by Ramirez, involves cutting the posterior rectus sheath, mobilizing soft tissue off of the external oblique fascia, and then incising the external oblique fascia approximately lateral to the linea semilunaris. This technique gained widespread popularity, but many have modified this technique simply to perform the soft tissue mobilization and external oblique incision. One of the most successful hernia repairs also uses component separation. Often called the “Rives-Stoppa” or retrorectus repair this procedure involves cutting of the posterior rectus sheath on both sides, sewing the posterior rectus sheath together, placing a mesh prosthetic in the retrorectus space, and then closing the anterior fascia. A more recent component separation technique involves cutting of the posterior rectus fascia. A recently reported component separation technique, described by Novitsky, often called transversus abdominis release involves performing a Rives-Stoppa repair but then cutting the transversus abdominis muscle proximal to the neurovascular bundles allowing re-entry into the preperitoneal space and placement of a large mesh prosthetic. The proposed benefit of this technique is it allows placement of large pieces of the mesh without making large skin and subcutaneous flaps that can increase the risk of wound infection.,
The complications of abdominal wall reconstruction are similar to any other major abdominal surgery. Adhesion lysis is often needed in these surgeries so the risk of bowel enterotomies and a plan if encountered should be discussed with the patient and known by the surgeon. Since this surgery usually requires major dissection of the skin and soft tissue, wound complications remain a common complication following surgery and range from simple surgical site infections to deep space infections and major skin/subcutaneous/flap necrosis. Mesh infections are a dreaded complication of abdominal wall reconstruction but typically can be minimized with good preoperative optimization, good surgical technique, and appropriate use of mesh prosthetics.
Abdominal wall defects are quite common and are becoming more complex. Knowledge of pertinent anatomy, preoperative optimization, techniques for repair, mesh use, and complications will allow the surgeon to deal with these difficult clinical problems.
The management of abdominal wall defects is challenging and complex. While once the domain of the general surgeon, today it is realized that reconstruction of the abdominal wall may also require the expertise of a plastic surgeon. To derive good outcomes, the goals and objective of the abdominal wall reconstruction have to be defined before taking the patient to surgery. In some cases, chronic infection may preclude definitive repair in a single stage, thus the importance of incorporating assistance from an infectious disease consult. As with any other complex procedure, the preoperative workup must be thorough and the patient should be seen by a pulmonologist and cardiologist to optimize lung and cardiac function. Because of the potential risk of injury to the bowel, bowel preparation is recommended. If an enterotomy occurs during surgery, prompt consultation from a general or colorectal surgery is appropriate.
To improve outcomes, the Ventral Hernia Working group has developed a 4-tier grading system based on risk fo a surgical site complication. However, evidence-based guidelines regarding the best approach for abdominal wall reconstruction are not available because of the heterogeneity in technique, types of sutures used, different prosthetic material, lack of long-term follow up and patient characteristics. While studies show that laparoscopic approach may have a better outcome compared to the open approach, the former is also associated with a high rate of bowel injury and conversion to an open procedure.
In the postoperative period, the role of the nurse and pharmacist is critical. The patients have to be monitored for pain, wound infection, fistula formation, and a variety of common postoperative complications such as atelectasis, deep vein thrombosis, ileus, and pain. The pharmacist may be involved in parenteral nutrition if a complication has resulted. With the ongoing debate about the approach to surgery, there is no disputing the fact that with each attempt at reconstruction, there is a 10% to 20% risk of recurrence. Thus, further emphasizing the need for an interprofessional approach to management of complex abdominal reconstructions. The need for meticulous planning and discussion with other professionals involved in the management of the patient is highly recommended to lower the morbidity and improve outcomes.  [Level A]