Single-Center Comparison of Laparoscopic Incisional Ventral Hernia Repair using Different Meshes

Results: The baseline characteristics of the three groups were similar. Recurrent ventral hernias were more frequent in the Dual MeshTM group (23.4 vs. 0 vs 0%; P=0.01). Perioperative complications and quality of life scores after surgery were also similar. Postoperative hematomas occurred in 3 (17.6%) patients in the ParietexTM group, in 1 (2.1%) patient in the Dual MeshTM group and in none of the patients in the Physio meshTM group (P=0.02). The incidence of recurrence was comparable, although the median follow-up was longer in the Physio meshTM group (57 months), P=0.001.


Introduction
The proper approach for ventral hernias, including both post incisional and primary defects, is still under debate. Therefore, no standard operative technique has been accepted by the surgical community due to the high incidence of postoperative morbidity and recurrence [1,2]. Nevertheless, laparoscopic incisional and ventral hernia repair (LIVHR) may represent an alternative to open surgery, avoiding wide recissions and accelerating postoperative return to normal activities. Despite a large number of encouraging papers, reviews, international guidelines [3][4][5][6][7][8][9] a meta-analysis [10] and a Cochrane review [11] suggested that LIVHR could be superior to the open approach; other works have reported equivalent/ inferior results or narrow indications [12][13][14][15].
Moreover, a major concern is which type of mesh is to be employed. Most leading surgeons agree that an intraperitoneal inert material should be left in contact with the bowel and viscous, although composite meshes (absorbable and non-absorbable layers merged) are an alternative option [16][17][18][19][20][21][22]. However, in many public health systems, not all commercial meshes with proper sizes are available, while in private systems, a conflict of interest could play a role in the decision of which is the best product. Therefore, large studies comparing the different types of meshes are still lacking.
The aim of the present study is to compare the results of LIVHR performed with different types of meshes in a public hospital.

Patients and Setting
A prospective database of LIVHR started in 2014 at Careggi Main Regional and University Hospital, Florence, Italy. All consecutive patients who underwent elective or urgent LIVHRs until December 2019 were retrospectively compared, grouping them according to the type of mesh employed. The indication for surgery was a ventral hernia (primary and post incisional) with a width greater than 2 centimeters in the maximum diameter. Smaller defects were managed under local analgesia with or without a small piece of mesh. No limitation was theoretically posed on the maximum range, but each surgeon was free to decide to use a minimally invasive technique, including for recurrent incisional hernias or urgency. All the involved surgeons had previous robust experience with this operation or were tutored by another surgeon who had experience (i.e., residents).  [23]. The general complications were recorded based on the Clavien-Dindo classification [24]. Patients were followed until discharge or 30 days postoperatively (whichever occurred later) and were then contacted during the outpatient visits or by phone calls for the medium/long-term follow-up (time of the present study). The primary objective was to assess the perioperative outcomes and the medium-to long-term follow-up, including the incidence of recurrence, reoperation, and quality of life (QoL), according to a structured specific questionnaire (Carolinas Comfort Scale, CCS) [25]. Patients who complained of symptoms of recurrence during phone interviews were also invited to the outpatient clinic for confirmation. In doubtful cases, further radiologic (CT scan) examination was also requested.

Surgical Technique
The laparoscopic technique was standardized among operating surgeons and published elsewhere [26], but each surgeon was free to choose his/her preference regarding the pneumoperitoneum, was also employed sporadically.

Grouping
The whole cohort of patients was divided according to the type of mesh employed, excluding those patients who underwent conversion to laparotomy and who had a polypropylene retro muscular mesh according to the Rives-Stoppa technique. Patients who underwent implantation of a type of mesh employed less than 5 times were excluded. Each participating surgeon was free to choose his/her preferred mesh, although the availability of a large spectrum of commercial meshes was not guaranteed, which was kept constant over the study period. Three definitive groups The details of the technical characteristics of each type of mesh are summarized in Table 1. Co-polymer poly-(glycolide-co-L-lactide) 365 d

Endpoints
The main endpoints were the determination of whether different types of meshes were related to postoperative complications, medium-to long-term outcomes (including QoL), and incidence of recurrence.

Statistics
Statistical and descriptive analyses were performed using the  Table 3.

Incisional Hernia Classification
Midline was also plotted to report the cumulative incidence of recurrence (5.8% at 36 months) ( Figure 1A). After proper calculation with the log-rank test, the incidence of recurrence, with the three different types of meshes, was not significantly different (P=0.58) ( Figure   1B).    Postoperative seroma formation is a frequent event (up to 10%), while true hematomas are also a reported occurrence [14].
Seroma/hematoma formation was a rare event in our casistic, without significant differences between groups, as reported by other authors for composite meshes [15]. A possible explanation could be found in the difference in the reporting of "seroma": according to some authors, only prolonged seromas (more than 2-4 weeks) should be considered a true complication [6,28]. To date, only one randomized controlled trial comparing mesh types (titaniumcoated lightweight mesh vs. standard composite mesh) has been published. The authors reported only less pain in the titaniumcoated mesh group, without any other significant differences [29].
In addition to mild perioperative impairments, the incidence of recurrence should be considered a major endpoint of hernia repair.
Our study revealed no statistically significant difference between the different types of meshes in terms of recurrence, even when performing a Kaplan-Meier survival curve to compare different lengths of follow-up.

Limitations
The main bias of the present study is that it is neither prospective nor randomized. However, the choice of one mesh rather than another was mainly related to each participating surgeon (nine staff surgeons supervising residents or colleagues), although the preferred mesh (or the proper size) was not always available, leading to some "single-day" randomization. For example, the Phisiomesh™ prosthesis was withdrawn from the market during the study period, without correlations to complications occurring at our hospital. Moreover, some conflicting results could be related to the different types of tax (i.e., absorbable or titanium) employed to secure the mesh, rather than the mesh itself [30,31]. This aspect was not taken into consideration in the present study, although most of the operations were completed by titanium tacks or a mix of titanium and absorbable tacks. Again, the same differences in the surgical technique, such as the occasional closure of the defect or the adjunct of trans fascial sutures, could also have played a role in determining the incidence of recurrence and outcome [32][33][34].

Conclusions
LIVHR is a safe and feasible technique for managing both primary and postincisional hernias. Despite the theoretical advantages of composite meshes, very few significant differences could be detected when compared to ePTFE in the present study.
Large multicenter randomized controlled studies without market or personal influences should be designed to choose the best product.