Incisional hernia after liver transplantation: mesh-based repair and what else?

Incisional hernia (IH) is a common complication after major surgery, with a reported incidence between 5 and 25% [1‐5]. Risk factors for an IH after major surgery include obesity, wound infection in the immediate postoperative setting, male gender, and diabetes mellitus [6‐15]. Further predisposing factors are collagen disorders, age, rapid weight loss, multiple pregnancies, chronic pulmonary disease, trauma, iatrogenic causes, and congenital disorders [12‐20]. Clinical examination and ultrasonography of the abdomen are the most sensitive diagnostic tools for an IH. After its diagnosis, surgical treatment is generally indicated because of the risk of serious complications, such as incarceration and strangulation of the protruding structures. In the posttransplant setting after orthotopic liver transplantation (LT) there are specific parameters, such as ascites and the continuous administration of immunosuppression, especially corticoids, which represent additional risk factors for IH after LT [8‐13, 15‐29]. Τhe type of incision, performed during the LT, also plays an important role. Janssen et al. described IH after LT occurring at the site where the horizontal incision meets the vertical incision [16]. There is also a correlation caused by a disturbed balance in the collagen I to collagen III ratio. Collagen III can have less mechanical stability than collagen I [17, 18]. Moreover, the discrepancy in size between the transplant and the intraabdominal space in the right hemiabdomen, increasing mechanical strain on the wound, may be a further causal factor for the development of an IH [12, 13, 16]. IHs usually develop within the first 24 months after major surgery [14, 16, 19].

Initially, there was scepticism regarding mesh hernia repair after LT, especially using the inlay/onlay technique, because of the perceived risk of major postoperative complications in patients under immunosuppression. However, several authors report that there is no increased morbidity between mesh and non-mesh hernia repair after LT [23, 26, 29]. We report the long-term results of mesh hernia repair using the inlay/onlay technique in patients with an IH after LT, focusing on postoperative and long-term morbidity, quality of life, and recurrence rates.

Incisional hernia, defined as the breakdown or loss of continuity of a fascial closure, is one of the most frequent complications of abdominal surgery. Patients in the posttransplant setting have a higher risk of the development of an IH, because of impairment in the wound healing processes and the higher incidence of wound infections [8, 10, 16, 22]. Furthermore, risk factors such as the presence of ascites, more than one laparotomy and acute rejection episodes play a role in the occurrence of IH after LT [12, 16, 23]. The incidence of IH in this series was 13%, which is comparable to that of other studies [10, 12, 16, 23, 24, 26, 28, 29]. Mesh-based hernia repair has been intensively discussed as the most appropriate option, considering the high recurrence rate (30–60%) after conventional suture repair [5, 16, 25‐29]. Despite initial criticism because of the potential infection risk of mesh in patients under immunosuppression, the low registered complication rate led to the establishment of mesh-based hernia repair. In fact, the recurrence rate after mesh-based hernia repair is very low, whereas other considerable complications, such as wound infection and chronic pain do not represent frequent events in terms of postoperative morbidity [16, 23‐26, 29]. In our collective, the fact that treatment with tacrolimus-based immunosuppression was given in a lower range without impairment of graft function, and the immunosuppression in patients with mTOR was switched to a CNI-based regimen, account for the low morbidity and recurrence rate in our patients.

The advantages of laparoscopic hernia repair as intraperitoneal onlay mesh repair (IPOM) include a shorter in-hospital stay and lower incidence of wound complications, particularly in the case of large or multiple hernia defects and in obese patients [2, 3, 21, 31]. The mesh we used for the IPOM technique is a dual-layer composite mesh (DynaMesh), composed of 88% high purity polyvinylidene fluoride (PVDF) and 12% polypropylene (PP). The size of the mesh is decided after identification of the fascial margin since the overlap has to be a minimum of 5 cm on all sides. The fixation can be achieved by transfascial sutures and clips, with tucks or glue [31]. Reported contraindications are severe adhesions and a “close-to-bone” situation, because of the high risk of severe chronic pain related to the fixation technique [31]. There is also a higher recurrence rate after repair of large IHs. Scheuerlein et al. reported a complication rate of 33% after IPOM vs. 21% after conventional mesh-based repair [31]. In our study, the mean hospital stay was 6 days, which was comparable to other studies, even to series in which patients underwent IPOM [21, 31].

Regarding postοperative morbidity, an infection around the onlay mesh developed in two patients, one of whom required its explantation. The first patient had a giant IH, 35 cm in diameter, and in the postoperative setting, a wound infection developed as a local infection around the onlay mesh, which could be treated conservatively. In this case of a larger abdominal wall defect, a component separation method could have been considered. Τhe second patient was on continuous prednisolone treatment for Crohn’s disease and the onlay mesh had to be explanted. However, there was no significant increase in postoperative morbidity among patients on a cortisone-based immunosuppressive regimen or on MMF (p = 0.194), as reported by others [31]. The morbidity rate and reoperation rate (for example, to remove the mesh) in our study were comparable to those in other series, which reported complication rates of 2–16% and mesh infection rates of 2.7–7.7% [11, 16, 21, 25, 26, 29, 40]. Furthermore, the hernia recurrence rate was very low (3.4%), and even lower than those in studies of patients who underwent laparoscopic hernia repair [11, 16, 25, 26, 28, 29, 31].

A limitation of the present study is its retrospective nature. Nevertheless, the data reported included all patients who underwent elective and emergency surgery with no exclusions and with a very long follow-up. Another limitation is that this study was performed in a single institution and the results obtained might not be comparable to those in other centers. However, unicentral studies have the advantage of minimizing the possible differences in surgical technique.

Incisional hernia is a frequent complication after liver transplantation. Our results demonstrate that mesh hernia repair using an onlay/inlay technique is an efficient and safe method of treating patients with an IH after LT. The recurrence rate was very low and the implantation of a mesh was not associated with increased morbidity, despite the continuous use of immunosuppression. Laparoscopic mesh hernia repair is an integral part of the surgical treatment of IH, but there are still some limitations regarding its indication, especially in patients with firm adhesions and a large hernia defect, and its long-term outcomes. Therefore, proper patient selection for this treatment modality is essential. To establish the best mode of hernia repair in these patients, the results and effectiveness of each technique must be analyzed in controlled studies.