Abdominal wall reconstruction following resection of large abdominal aggressive neoplasms using tensor fascia lata flap with or without mesh reinforcement

Abdominal wall neoplasms are not only found in skin, subcutaneous tissue, muscles, fascia, and peritoneum, but also can be caused by direct spreading from gastric, gallbladder, and colorectal carcinomas. Neoplasms can be classified into benign, borderline, and malignant according to the pathological morphology. Fibromas, lipomas, and hemangiomas are the most common benign tumors, found in 26–40% of abdominal wall tumors. Malignant neoplasms, including fibrosarcomas, leiomyosarcomas, and lymphangiosarcomas, originate from soft tissue mesenchymal sarcomas (STSs) and account for 5% of abdominal wall neoplasms and 1% of all tumors [1]. The biological characteristics of borderline neoplasms, which fall somewhere between benign and malignant, include a lack of encapsulation, invasiveness, and slow growth that rarely result in distant metastases. Desmoid tumors and dermatofibrosarcoma protuberans are two common types of borderline neoplasms. Currently, surgery is the main treatment for abdominal wall neoplasms, and when defects are too large after tumor excision, surgeons should repair the abdominal wall defects using mesh reinforcement, component separation techniques (CST), or autologous flap repair to achieve a better result for the patients.

Autologous flaps, such as transverse rectus abdominis myocutaneous (TRAM) and tensor fascia lata (TFL) are common techniques for reconstructing abdominal wall defects. Among these, TFL is the most common muscle flap procedure, which can cover a donor area up to 40 × 25 cm². It eliminates complications and makes it good for abdominal wall defect repair. However, the recurrence rate of hernia using TFL alone is up to 40% because of the poor mechanical strength of the tissue [2]. Therefore, in clinical practice, we combine autologous flap repair with prosthetic or biological materials to increase the mechanical strength of abdominal wall, and reduce the risk of postoperative hernia.

Mesh plays important roles in the process of reconstruction of the abdominal wall. Polypropylene (PP) could significantly reduce the recurrence; however, its non-absorbable characteristic can cause infection and chronic pain in some situations [3, 4]. It can even cause serious complications, such as bowel adhesion, obstruction, and fistula formation [5‐7]. Therefore, composite mesh or biological mesh is more often used in abdominal wall reconstruction.

Compared with prosthetic mesh, biological mesh offers better biocompatibility and reduced susceptibility to infection. In the United States, biological mesh, such as pig small intestinal submucosa (PSIS), pig skin acellular dermal matrix (PADM) and human skin acellular dermal matrix (HADM) have been available for over 10 years for use in abdominal wall reconstruction, and each material shows promising results in the repair of these defects. Because acellular mesh, both SIS and ADM, are mainly comprised of collagen, which provides a three-dimensional structural environment allowing adhesion, growth, and migration of the host cell. Many glycoproteins and proteoglycans in SIS contain specific sites on their protein portions that facilitate host-derived cell attachment within the three-dimensional structure, and thereby contribute to the repopulation of the matrix and the cellular processes necessary for remodeling into mature functional tissue. ADM has also been promoted to encourage collagen deposition and neovascularization, which potentially reduces infection rates [8] and are widely used in treatments of recurrent hernias, dural repair, and abdominal wall reconstruction [9‐11].

Given the advantages above, SIS and ADM mesh are often combined with synthetic meshes to repair abdominal wall defects, especially for complex cases with or without infection.

In our study, 18 TFL flaps with or without mesh were used to reconstruct full-thickness abdominal wall defects caused by abdominal wall neoplasms. Our patients had favorable results during follow-up; so, we herein gathered and assembled our experiences.

We retrospectively reviewed 18 patients with aggressive neoplasms invading abdominal wall partially or fully. Between March 2007 and October 2016, the patients underwent radical resection with a one-stage abdominal wall reconstruction using a TFL flap. All patient information was retrospectively collected in a record review, including basic patient information, preoperative examination, surgical treatment, pathological results, and postoperative results (general complications, length of stay, and long-term follow-up).

Abdominal wall defects are caused by events such as trauma, infection, surgery, and abdominal wall neoplasms. The best treatment method is aggressive resection with adequate clear margins, which may generate a large, complex abdominal wall defect. If the neoplasm invades surrounding tissues, such as bone, large vessels, or organs, especially when combined with infection or heavy contamination, the defect can be even greater. In such cases, reconstruction becomes extremely complex, presenting a formidable challenge for surgeons. Generally, large defects (> 6 cm in diameter) should be reconstructed using synthetic or biological mesh or autologous flaps [13] In our study, 12 patients used the mesh and 6 patients did not. According to our surgical treatment proposal (Fig. 3), not all abdominal wall defects require mesh placements. Moreover, both the size of the defect and the type of the flap should be considered during reconstruction. When the defects are small, the application of a flap alone can provide sufficient mechanical strength for repair.

Polypropylene (PP), a typical synthetic material, can dramatically reduce the rate of hernia formation by providing sufficient strength for an abdominal wall repair [3, 4]. It bridges the defect and allows a low-tension or tension-free repair because of its stability, strength, inertness, and handling characteristics. However, synthetic mesh can lead to serious complications, such as infection, chronic pain, and bowel adherence or even obstruction [5, 6, 14, 15]. In particular, when a synthetic mesh is applied to contaminated wounds, its removal is required in 50–90% of cases [16]. In addition, when placed in contact with the bowel, the PP mesh tends to promote adhesions to the bowel, which sometimes result in fistula formation. Therefore, many meshes have been developed by encapsulating a bio-resorbable layer to physically separate the PP mesh from the underlying tissue and organ surfaces, thus minimizing tissue attachment and reducing adhesions.

The introduction and recent popular use of biological mesh consisting of human (allograft) and animal (xenograft) products have given the surgeon an alternative for hernia repair. Many studies have reported that there is enough clinical evidence to support biological meshes being used safely with a lower recurrence rate of infected or contaminated fields where synthetic meshes are contraindicated [17]. Thus, the use of biological mesh in these types of repair has become the preferred method. Biological mesh consists of an extracellular collagen matrix that gradually resorbs and remodels, and deposits new collagen and regenerates tissue. During this process, these biological meshes are thought to offer a collagen framework to allow cellular regeneration, neovascularization, and potentially fascial replacement [18]. Commercially available biological mesh for abdominal wall reconstruction can be derived from human and porcine dermis, porcine small intestinal submucosa, or bovine pericardia. According to the literature, porcine small intestinal submucosa (SIS) and human acellular dermal matrix (ADM) meshes have been commonly and successfully used for abdominal wall reconstruction with successful hernia repair and resistance to infection in contaminated fields [19]. Helton et al. reported a retrospective case series of 53 patients having eight-ply SIS mesh repair or ventral abdominal hernia in clean, clean-contaminated, and dirty fields with a mean follow-up of 14 months. There was a 17% recurrence (78% in dirty wounds), 11% mesh reaction, and 21% partial dehiscence rate, which concluded that SIS was safe for clean and clean-contaminated hernia repair [20]. Garvey et al. conducted a retrospective study to evaluate the safety and efficacy of abdominal wall reconstruction using ADM in 359 patients. There were no significant differences between clean and combined contaminated cases with regard to surgical site infection (8.8 vs. 8.0%), hernia recurrence (9.9 vs. 10.1%), and mesh removal rates (1.2 vs. 1.1%) during follow-up over a 9-year period [21]. These data support the use of biological mesh and suggest that it may offer better safety and efficacy in reconstructing abdominal wall defects with clean or clean-contaminated wounds, while worse results are obtained with contaminated or dirty-infected wounds. In this study, PSIS and HADM were used in 10 patients, 7 of whom had incisional infection before surgery; only one patient caused incisional infection.

The abdominal wall is a multilayered structure composed of several different tissues. Therefore, defects can be quite diverse. We categorized the defects into three types, according to the defective components of the abdominal wall. Most type I defects were easily repaired, and none of these cases are described in this article. A type II defect was caused by a defect of the myofascial layer, which is the major supportive part of the abdominal wall, necessary to protect the abdominal contents and allow dynamic function. Many methods, including synthetic or biological mesh, autologous flaps, and CST techniques, can be chosen for reconstruction. We believe that mesh should be the base of the CST or flaps. If mesh is used, especially synthetic mesh, the rate of hernia formation is significantly lower; however, a synthetic mesh is not suitable for contaminated or dirty wounds because of the high complication rates in a chronic situation with sinus formation or loss of the synthesis. In contrast, biological mesh and/or an autologous flap are/is the best choice for contamination cases. No hernia or incisional hernia was observed in these patients because of the short follow-up time (22.8 ± 34.38 months). In our experience, synthetic mesh achieved sufficient mechanical strength to restore abdominal wall integrity and prevented hernia formation or bulging of the intra-abdominal contents. Biological mesh, as an extracellular matrix, is shaped and transformed continually within the body to maintain the function of the abdominal wall.

There are two ways to reconstruct an abdominal wall defect with mesh: the suture bridge technique, and the mesh reinforced technique. Both are recommended for all kinds of defects because of lower recurrence rates and less incision complications. Deerenberg has reported that mesh reinforced techniques to repair incisional hernia displayed better recurrence rates (< 3.6%) and hazards (< 0.5%) than techniques without mesh reinforcement (12–44%) by 55 articles and 3954 incisional hernia repairs [22]. In our study, the suture bridge technique was used for three patients because of large defects covering nearly the entire abdominal wall (425 ± 43.3). Regardless of the CST, abdominal organ resection or other methods, it is impossible to close the defect. In a large abdominal wall defect such as this, the only way is to use the suture bridge technique to repair the defect.

Generally, we placed different tubes in different locations during the operation to achieve sufficient drainage. One tube was placed in the pelvic cavity, two tubes were located between the synthetic and biological mesh, and one tube was located above the biological mesh. If the peritoneal defect is repaired with biological mesh, then one tube should be placed above the mesh. If the subcutaneous tissue is extensively manipulated or CST is performed during the operation, one or two tubes should also be placed. Adequate drainage is very important for patients with mesh or flaps, and reduces the risk of postoperative infection. In our study, two patients with hematomas ultimately developed wound infections, mostly because the large defect caused relatively inadequate drainage. The onlay (placing the mesh above the rectus muscles and anterior sheath), sublay (placing the mesh under the rectus muscles and anterior to the posterior sheath and peritoneum), and intraperitoneal onlay mesh (IPOM) (placing the mesh under the peritoneum inside the abdominal cavity) methods can also be used for repairs. Successful repair requires effective mesh bridging or augmentation of the abdominal wall. De Vries Reilingh et al. retrospectively reviewed midline incisional hernia repair performed on 53 patients using either open inlay, sublay, or onlay techniques. They observed that the onlay technique had significantly more complications, while the inlay mesh technique should be avoided because of the higher reherniation rate (44, 12, 23%). Thus, the underlay technique seemed to be the best technique [23]. Eriksson et al. [24] analyzed 14 studies and showed the results of giant incisional hernias after repair and found that the inlay technique and repair without a mesh should be avoided, and mesh augmentation was preferable in the sublay position.

Type III abdominal wall defects, both myofascial and skin coverage defects, should be repaired by myocutaneous flap, such as TFL, latissimus dorsi flap, external oblique flap, internal oblique flap, rectus femoris flap, or omental flap. The latissimus dorsi flap is widely used for breast or chest wall reconstruction; internal oblique flaps are small, and dissection can be bloody and tedious [25]. Rectus femoris flaps may cause significant knee weakness [26]. TFL is the most often used and is the most appropriate flap for abdominal wall reconstruction because of two advantages: its collagen fibers are strong enough to resist intra-abdominal pressure, and the skin and muscle can cover defects with full blood supply and nerve distribution. Fast revascularization and preservation of its physical properties after implantation make it nearly ideal for fascial substitute. Although the wound complication rate was high, up to 40%, no graft was lost and the recurrence rate was similar to CST [27]. However, the abdominal wall defects caused by extended resection of the tumor were usually too large for one flap to repair. Therefore, the denervated muscle cannot resist the intra-abdominal pressure, which results in bulging of the abdominal wall over time, and application of muscular flaps alone for large abdominal wall defects is not advised.

Overall, in our opinion, most type I defects should be primary sutured; type II or III defects should be repaired well by flaps, with or without mesh; if the incision is infected or contaminated, biological mesh or flaps are the best choice. Given the nature of abdominal wall tumors, especially for secondary tumors, the mean survival time of patients was very short. Regrettably, we could not obtain the long-time follow-up record to verify the feasibility of surgical methods.