Bioprosthetic tissue matrices in complex abdominal wall reconstruction

Prophylactic Biosynthetic Retrorectus Mesh Placement During Stoma Reversal Reduces the Rate of Stoma Site Incisional Hernia

INTRODUCTION

Stoma site incisional hernias (SSIHs) are associated with substantial long-term morbidity, and the rate can be as high as 30% to 40%. Recent efforts using prophylactic mesh reinforcement (PMR) to reduce the development of hernias have shown encouraging outcomes. The objective of this study was to assess the use of prophylactic biosynthetic mesh at the time of stoma reversal on the overall SSIH rate.

METHODS

This is an observational retrospective cohort study. A review of 101 consecutive patients who underwent PMR in the retrorectus plane from 2015 to 2020 was compared to 73 consecutive patients who underwent primary stoma closure without mesh from 2011 to 2014. The primary endpoint was the presence of SSIH on clinical examination or computed tomography after ostomy takedown.

RESULTS

In total, 174 cases were analyzed with 101 patients in the treatment group (median follow-up 45.2 months) and 73 patients in the control group (median follow-up 43.2 months). There were no major differences in preoperative characteristics between the groups. Fourteen patients developed SSIHs with 1 (1.0%) in the treatment arm and 13 (17.8%) in the control arm (p = 0.001). The majority of stomas were loop ileostomies and end colostomies, and stoma type did not affect hernia rates. On univariate analysis, body mass index (p = 0.029) and chronic kidney disease < 3 (p = 0.003) were independent predictors of hernia formation, while mesh was significantly protective (p = 0.000057).

DISCUSSION

PMR with biosynthetic mesh at the time of stoma reversal and closure is an effective procedure to reduce the incidence of SSIHs and does not seem to be associated with an increased risk of complications.

Dermal Matrices: Do We Always Know What Is Going On?

The use of dermal matrices in abdominal wall reconstruction has gained increased attention over time, particularly in contaminated fields. One of their advantages is the greater capacity to resist infection. We report a case of a 36-year-old man, with congenital bladder exstrophy and neobladder reconstruction during childhood. He presented to us with an abdominal hernia associated with a vesicocutaneous fistula. We used a bovine-derived dermal matrix (SurgiMend®, TEI Biosciences, MA, USA) for reinforcement of the abdominal repair considering its laboratory-proven mechanical superiority regarding strength. The early postoperative period was complicated by an infection that led to mesh disintegration and the need for surgical revision. We believe that matrix digestion by bacterial enzymes culminated in rapid breakdown of the product. Further investigations are warranted to determine optimal selection criteria and indications of bioprosthesis in contaminated wounds. Surgeons should be cautious when selecting a biologic mesh in these cases, favoring meshes with a better integration profile.

The Use of Biologic Wound Agents in Pediatric Reconstructions

The indications for using biologic wound agents have expanded greatly since first being employed for acute burn management. The majority of the literature details the use of said agents in the adult population; however, there is little representation regarding their uses for reconstructing defects typically observed in the pediatric population. Ironically, children, and to a lesser extent adolescents, greatly benefit from their use given the reduced skin laxity and amount of surrounding tissue available for locoregional tissue transfer when compared with adults. Herein, we detail the use of acellular and cellular biologic wound agents in the pediatric population.

What is the evidence for the use of biologic or biosynthetic meshes in abdominal wall reconstruction?

INTRODUCTION

Although many surgeons have adopted the use of biologic and biosynthetic meshes in complex abdominal wall hernia repair, others have questioned the use of these products. Criticism is addressed in several review articles on the poor standard of studies reporting on the use of biologic meshes for different abdominal wall repairs. The aim of this consensus review is to conduct an evidence-based analysis of the efficacy of biologic and biosynthetic meshes in predefined clinical situations.

METHODS

A European working group, "BioMesh Study Group", composed of invited surgeons with a special interest in surgical meshes, formulated key questions, and forwarded them for processing in subgroups. In January 2016, a workshop was held in Berlin where the findings were presented, discussed, and voted on for consensus. Findings were set out in writing by the subgroups followed by consensus being reached. For the review, 114 studies and background analyses were used.

RESULTS

The cumulative data regarding biologic mesh under contaminated conditions do not support the claim that it is better than synthetic mesh. Biologic mesh use should be avoided when bridging is needed. In inguinal hernia repair biologic and biosynthetic meshes do not have a clear advantage over the synthetic meshes. For prevention of incisional or parastomal hernias, there is no evidence to support the use of biologic/biosynthetic meshes. In complex abdominal wall hernia repairs (incarcerated hernia, parastomal hernia, infected mesh, open abdomen, enterocutaneous fistula, and component separation technique), biologic and biosynthetic meshes do not provide a superior alternative to synthetic meshes.

CONCLUSION

The routine use of biologic and biosynthetic meshes cannot be recommended.

Practical Approaches to Definitive Reconstruction of Complex Abdominal Wall Defects

With advances in abdominal surgery and the management of major trauma, complex abdominal wall defects have become the new surgical disease, and the need for abdominal wall reconstruction has increased dramatically. Subsequently, how to reconstruct these large defects has become a new surgical question. While most surgeons use native abdominal wall whenever possible, evidence suggests that synthetic or biologic mesh needs to be added to large ventral hernia repairs. One particular group of patients who exemplify "complex" are those with contaminated wounds, enterocutaneous fistulas, enteroatmospheric fistulas, and/or stoma(s), where synthetic mesh is to be avoided if at all possible. Most recently, biologic mesh has become the new standard in high-risk patients with contaminated and dirty-infected wounds. While biologic mesh is the most common tissue engineered used in this field of surgery, level I evidence is needed on its indication and long-term outcomes. Various techniques for reconstructing the abdominal wall have been described, however the long-term outcomes for most of these studies, are rarely reported. In this article, I outline current practical approaches to perioperative management and definitive abdominal reconstruction in patients with complex abdominal wall defects, with or without fistulas, as well as those who have lost abdominal domain.

Porcine acellular dermal matrix (PADM) vascularises after exposure in open necrotic wounds seen after complex hernia repair

Biological alternatives to synthetic meshes are increasingly utilised in complex abdominal wall reconstruction. There is a lack of evidence demonstrating that non-cross-linked porcine acellular dermal matrix vascularizes and integrates with human tissue in suboptimal wound conditions. We aimed to evaluate these properties in Strattice™ (Life Cell Inc., Branchburg, NJ) following ventral hernia repair. A retrospective review of patients with high-risk ventral hernia repair utilising Strattice™ as an onlay after open component separation was conducted. Patients with postoperative wound exploration and exposure of the onlay were included in this review. One patient underwent punch biopsy for histological analysis. Eleven patients with wound complications necessitating postoperative debridement and exposure of Strattice™ onlay were identified. The onlay was partially debrided in two cases, and one case required complete excision. Vascularisation was clinically evident in 10 of 11 cases (91%) as demonstrated by the presence of granulation tissue and/or the ability to support a skin graft. Histological analysis of one onlay 3 months postoperatively showed neovascularisation and collagen remodelling with minimal inflammatory response. Strattice™ demonstrated resistance to rejection, ability to undergo vascularisation and incorporation into host tissues in sub-optimal wound conditions following ventral hernia repair.

Bovine fetal collagen reinforcement in a small animal model of hernia with component repair

BACKGROUND

Component separation is a surgical strategy used to achieve abdominal wall reconstruction for patients with significant ventral hernias. With an increasing number of variations in procedural techniques and materials, the development of a small animal model of this surgery would allow for the controlled evaluation of variables with analytics not available in human clinical studies. To test this model, we investigated the reinforcement of these component repairs in rats with a bovine fetal collagen (BFC) scaffold.

METHODS

Fifty Sprague Dawley rats were randomized into either component repair alone or BFC reinforced component repair. At time points up to 1 y, these groups were evaluated for hernia formation, strength of repair, strength of mesh-muscle interface, and histology of the repair site.

RESULTS

Anterior component separation was achievable and reproducible in this small animal model. Significantly fewer hernias were found in BFC reinforced repairs. The change in transverse abdominal length was lower for reinforced repairs indicating less external oblique retraction, and reinforced repairs were consistently stronger than controls through 1 y. BFC was revascularized and repopulated with host cells but not rapidly degraded.

CONCLUSIONS

This small animal model of hernia repair with anterior component separation was effective in evaluating the reinforcement of a hernia repair with mesh. It may be useful in future work for the controlled, comparative investigation of different repair techniques and mesh materials in anterior component separation hernia repairs. Additionally, bovine fetal collagen was found to effectively reinforce component repairs and undergo an assimilation process including rapid revascularization and repopulation with host cells followed by gradual extracellular matrix remodeling.