Possible areas of concern in the future
Bioabsorbable synthetic mesh: recurrences, seroma?
Non fixation: long-term recurrence rate
SIL repair: port site incisional hernia
Robotic hernia repair ??
Cellular therapies: rejection, sepsis, viability New synthetic and biologic matrices: foreign body reaction, unpredictable behavior (resorption, integration)
19.2 19.2 Mesh-related Complications
19.2.1 19.2.1 Biologic Meshes
It is highly unlikely that biologic meshes will play a relevant role in inguinal hernia repair in the future. In consequence, it should be sufficient to point out that there is no clinical evidence for superiority over synthetic meshes in inguinal hernia repair or any other indication. A recent publication in the ANZ Journal of Surgery demonstrated that biologic inguinal hernia repair was associated with longer operation times and more seroma formation compared to standard mesh repair .
19.2.2 19.2.2 Bioabsorbable Synthetic Meshes
A new class of synthetic mesh was introduced to the market in the recent past, namely bioabsorbable implants, such as BioA (polyglycolic acid/trimethylene carbonate), TIGR (polylactic and polyglycolic acid) and Phasix (poly-4-hydroxybutyrate). Potential advantages include rapid integration and a mild foreign body reaction compared to biologic meshes. Compared to the other above mentioned meshes, the BioA represents a 3D matrix rather than a 2D mesh layer. TIGR and Phasix are more conventional in design, but all three share the feature of being resorbed in 9 to 24 months after implantation. Our study group could demonstrate that the BioA actually reinforces the abdominal wall by eliciting a robust scar formation, yielding reticular collagen formation. If this is also achieved by the other competitors has, to the best of our knowledge, not been investigated in detail yet. Considering the ongoing debate about genetic and epigenetic factors influencing hernia formation, it is totally unclear if resorbable meshes could lead to an increased rate of recurrences.
This issue will become even more important as a variety of synthetic, resorbable meshes will enter the market in the near future. Furthermore, it must be emphasized that the resorption process of these implants (most of them polyglycolic/polylactic acid derivatives) could lead to seroma formation or prolonged local inflammation. Because bioabsorbable, synthetic meshes have been presented as direct competitors of collagen matrices, many surgeons are eager to use them in contaminated wound fields. The first study using BioA in contaminated fields (CDC class 2 and 3 ) with promising results was published recently . The future will show how these new meshes will perform in other than clean wounds (e.g., after resection of incarcerated bowel).
19.2.3 19.2.3 Polypropylene and Polyester Meshes
Although polypropylene and polyester meshes are the most commonly used implants in hernia repair and are usually well tolerated, it is currently unclear how these polymers behave in terms of aging and mechanical breakdown. If implanted in young adults, meshes will have to perform for up to seven decades considering the life expectancy in developed countries. There is at least some evidence that differences between polypropylene and polyester can be found . However, this question must be elucidated in more detail in the future.
19.3 19.3 Fixation-related Complications
While there is an impressive safety record for biologic sealants (e.g., fibrin sealant such as Tisseel/Tissucol, Baxter, Round Lake, USA) , the long-term effects of other atraumatic fixation methods are fully unknown. The application of cyanoacrylates is tempting because of quick adhesion and easy use. It has repeatedly been demonstrated that cyanoacrylates impair tissue integration , can exert serious damage to instruments and are inadequate for being sprayed in a uniform layer. Although it is true that the clinical importance of these observations has not yet been verified, the progress with cyanoacrylates for mesh fixation in inguinal hernia repair should be critically followed over the next years.
The analysis of recurrence rates and local pain sensation will also be worthwhile for self-gripping meshes, like Covidien-Medtronic’s Progrip mesh . While the concept is intriguing and the likelihood of complications is low, it is important to know that the resorption rate of the polylactic acid (PLA) grips seem to vary between individuals . If and how this could translate to mesh dislocation and prolonged foreign body reaction is again unclear.
The major topic in the area of fixation-related complications could be the consequences of non-fixation. Non-fixation of meshes is nothing new in totally extra-peritoneal (TEP) repair and has become an accepted alternative in transabdominal preperitoneal (TAPP) repair as well . In awareness of recent modifications in the guidelines  embracing non-fixation in laparoscopic inguinal hernia repair, it must be emphasized that the long-term impact on recurrence rates cannot be fully appreciated yet. In other words, more randomized controlled trials will be needed to falsify the hypothesis that non-fixation is generally unproblematic.
19.4 19.4 Procedure-related Complications
Refned operating techniques and sophisticated materials have elevated the standard of care to a high level. Procedure-related complications usually arise when techniques are changing because of innovations in instruments or new scientific insights. In most cases it will be a combination of both, e.g., it was the insight that postoperative pain could be reduced by atraumatic fixation that led to the development of specialized fibrin sealants and application devices; the reported complication was a rise of the incidence of seromas in TAPP, because surgeons initially used too much sealant. Today and in the future the main procedural changes are represented by single-incision laparoscopic (SIL) repairs  and the introduction of robotics to hernia repair.