Evaluation of a novel synthetic material for closure of large abdominal wall defects

A Review of Advanced Abdominal Wall Hernia Patch Materials

Tension-free abdominal wall hernia patch materials (AWHPMs) play an important role in the repair of abdominal wall defects (AWDs), which have a recurrence rate of <1%. Nevertheless, there are still significant challenges in the development of tailored, biomimetic, and extracellular matrix (ECM)-like AWHPMs that satisfy the clinical demands of abdominal wall repair (AWR) while effectively handling post-operative complications associated with abdominal hernias, such as intra-abdominal visceral adhesion and abnormal healing. This extensive review presents a comprehensive guide to the high-end fabrication and the precise selection of these advanced AWHPMs. The review begins by briefly introducing the structures, sources, and properties of AWHPMs, and critically evaluates the advantages and disadvantages of different types of AWHPMs for AWR applications. The review subsequently summarizes and elaborates upon state-of-the-art AWHPM fabrication methods and their key characteristics (e.g., mechanical, physicochemical, and biological properties in vitro/vivo). This review uses compelling examples to demonstrate that advanced AWHPMs with multiple functionalities (e.g., anti-deformation, anti-inflammation, anti-adhesion, pro-healing properties, etc.) can meet the fundamental clinical demands required to successfully repair AWDs. In particular, there have been several developments in the enhancement of biomimetic AWHPMs with multiple properties, and additional breakthroughs are expected in the near future.

Effectiveness of the combined use of lactic acid film and polypropylene mesh in the formation of intraperitoneal adhesions--an experimental model in rats

OBJECTIVE

To evaluate the efficacy of a lactic acid biomaterial (SurgiWrap®) as a protector of the polypropylene mesh (Marlex®) regarding the formation of intraperitoneal adhesions in rats.

METHODS

Forty Wistar rats formed the following groups: Group 0 (Sham)--only laparotomy; Group I--polypropylene mesh; Group II--polypropylene mesh protected by a film of lactic acid. These animals were submitted to laparotomy and placement (or not) of the meshes at closing. After 21 days they were sacrificed for analysis of the adhesion type (0-3), percentage of affected area and strength needed to rupture.

RESULTS

Group 0 showed no intraperitoneal adhesions. Regarding classification, type 3 adhesions had the highest prevalence in both groups 1 and 2. As for the strength to break adhesions, Group 1 had an average of 1.58 N and Group 2, 1.23 N. The mesh was surrounded by adhesions in more than 50% of their surface area in 87% of Group 1 subjects and in 84% of Group 2 individuals. Through different statistical methods we found that there was no significant difference between groups for both variables.

CONCLUSION

The combined use of polypropylene mesh and lactic acid bioprotector showed similar results in relation to intraperitoneal adhesion formation when compared to the sole use of the same mesh.

Comparison of novel synthetic materials with traditional methods to repair exposed abdominal wall fascial defects

Repair of large abdominal wall defects is a challenge, particularly when full-thickness tissue loss prohibits coverage of the fascial repair. Two novel synthetic materials (TMS-1 and TMS-2) have been shown to be better accepted than expanded polytetrafluoroethylene (Gore-Tex), and polypropylene (Marlex) in the closure of clean and contaminated fascial wounds that are immediately covered by skin/soft tissue. Therefore, 1-cm2 abdominal wall defects were created in each of the four quadrants of rat groups. Gore-Tex, Marlex, and TMS-1 or TMS-2 were used to repair three defects, the fourth being primarily closed. To ensure that each repair remained exposed, skin edges were sutured to underlying muscle. Additional animal groups underwent the same protocol; however, peritonitis was induced at surgery using a fecal inoculum technique. Animals were sacrificed 2 weeks later, at which time a blinded observer assessed the surface area and severity of adhesions. In clean wounds, the surface area of formed adhesions was less (p < .004) after primary closure than each synthetic material; among the synthetics, TMS-2 caused significantly (p < .01) less extensive adhesions than Marlex. In addition, the severity of adhesions to TMS-2 was comparable to that of defects closed primarily, and less severe (p < .02) than those formed to Gore-Tex and Marlex. In animals with peritonitis, primary closure caused less extensive (p < .03) adhesions than Marlex and Gore-Tex and significantly (p < .002) less severe adhesions than Marlex, Gore-Tex, and TMS-2. However, the severity of adhesions formed to TMS-1 repairs proved comparable to primarily closed wounds. These experiments reaffirm the tenet that, whenever possible, abdominal wounds should undergo primary fascial closure. When soft tissue coverage over the repair cannot be achieved, TMS-2 is well tolerated in clean wounds. However, the superiority of TMS-1 over the other synthetic materials in contaminated wounds suggests it may also ultimately prove to be of clinical utility.