Experience with Porcine Acellular Dermal Collagen Implant in One-stage Tension-free Reconstruction of Acute and Chronic Abdominal Wall Defects

Ventral Hernia Repair: Does Mesh Position Matter?

Mesh positioning is a commonly discussed detail in ventral hernia repair and is often cited as a major contributor to the outcome of the operation. However, there is a paucity of data that establishes one plane as superior to others. In this article, we will provide an overview of all potential planes to place prosthetic material and review the relevant literature supporting each option and the complications associated with accessing each anatomic plane.

Overview of Biologic Agents Used in Skin and Soft Tissue Reconstruction

Wound healing is a highly complex process mediated by cellular interactions at the microscopic level. Increased understanding of wound healing physiology has served as the foundation for translational research to develop biologic wound care technologies that have profoundly affected patient care. As the reader will see throughout this series in Seminars in Plastic Surgery , biologic wound technologies have broad applications and have greatly impacted the reconstructive ladder. Despite their frequent use, many surgeons lack familiarity with the myriad of products available on the market along with each product's relative advantages and shortcomings. This overview will discuss the classification of biologic wound agents used to reconstruct defects of the skin and soft tissue along with the advantages and disadvantages associated with their use.

A retrospective, Italian multicenter study of complex abdominal wall defect repair with a Permacol biological mesh

Complex abdominal wall defects (CAWDs) can be difficult to repair and using a conventional synthetic mesh is often unsuitable. A biological mesh might offer a solution for CAWD repair, but the clinical outcomes are unclear. Here, we evaluated the efficacy of a cross-linked, acellular porcine dermal collagen matrix implant (Permacol) for CAWD repair in a cohort of 60 patients. Here, 58.3% patients presented with a grade 3 hernia (according to the Ventral Hernia Working Group grading system) and a contaminated surgical field. Permacol was implanted as a bridge in 46.7%, as an underlay (intraperitoneal position) in 38.3% and as a sublay (retromuscolar position) in 15% of patients. Fascia closure was achieved in 53.3% of patients. The surgical site occurrence rate was 35% and the defect size significantly influenced the probability of post-operative complications. The long-term (2 year) hernia recurrence rate was 36.2%. This study represents the first large multi-centre Italian case series on Permacol implants in patients with a CAWD. Our data suggest that Permacol is a feasible strategy to repair a CAWD, with acceptable early complications and long-term (2 year) recurrence rates.

A novel tool to evaluate bias in literature on use of biologic mesh in abdominal wall hernia repair

PURPOSE

Biologic meshes are being increasingly used for abdominal hernia repair in high-risk patients or patients with a previous history of wound infection, due to their infection-resistant properties. Several studies have been carried out to assess whether biologic mesh is superior to synthetic mesh, as well as to establish guidelines for their use. Unfortunately, most of these studies were not rigorously designed and were vulnerable to different types of bias. The systematic reviews that have been published so far on this topic contain the same biases and limitations of the primary articles that are analyzed. The lack of a literature review on the bias on the use of biological mesh prompted us to conduct the literature search, assessment and plan this article.

METHODS

We performed a literature search in PubMed, Embase and Cochrane databases of systematic reviews on biologic mesh for ventral hernia repair. The literature review was conducted using the Population, Intervention, Comparisons, Outcomes and Design approach. We identified 40 studies that matched the stringent criteria we had set. We then created a 13-point instrument to assess for bias and applied it on the primary studies that we intended to analyze.

RESULTS

Most primary studies are case series or case reports of patients undergoing abdominal hernia repair with biologic mesh, without any comparison group, and the inclusion of cases was only specified to be consecutive in 6 out of 40 cases. In terms of assessing outcomes, in none of the 40 articles were the outcome assessors blinded to the intervention or exposure status of participants.

CONCLUSION

The instrument that we created could allow to assess the risk of bias in different kind of studies. Our assessment of the studies based on the criteria that we had set up in the instrument clearly identified that further research needs to be done due to the lack of unbiased studies regarding the use of biologic meshes for abdominal hernia repair.

Systematic review of the stage of innovation of biological mesh for complex or contaminated abdominal wall closure

Background

Achieving stable closure of complex or contaminated abdominal wall incisions remains challenging. This study aimed to characterize the stage of innovation for biological mesh devices used during complex abdominal wall reconstruction and to evaluate the quality of current evidence.

Methods

A systematic review was performed of published and ongoing studies between January 2000 and September 2017. Eligible studies were those where a biological mesh was used to support fascial closure, either prophylactically after midline laparotomy, or for reinforcement after repair of incisional hernia with midline incision. The primary outcome measure was the IDEAL framework stage of innovation. The key secondary outcome measure was the GRADE criteria for study quality.

Results

Thirty‐five studies including 2681 patients were included. Four studies considered mesh prophylaxis, 23 considered hernia repair, and eight reported on both. There was one published randomized trial (IDEAL stage 3), none of which was of high quality; the others were non‐randomized studies (IDEAL stage 2a). A detailed description of surgical technique was provided in most studies (27 of 35); however, no study reported outcomes according to the European Hernia Society consensus statement and only two described quality control of surgical technique during the study. From 21 ongoing randomized trials and observational studies, 11 considered repair of incisional hernia and 10 considered prophylaxis (seven in elective settings).

Conclusion

The evidence base for biological mesh is limited, and better reporting and quality control of surgical techniques are needed. Although results of ongoing trials over the next decade will improve the evidence base, further study is required in the emergency and contaminated settings.

Evaluation of a bioengineered construct for tissue engineering applications

Effective biomaterial options for tissue repair and regeneration are limited. Current biologic meshes are derived from different tissue sources and are generally sold as decellularized tissues. This work evaluated two collagen based bioengineered constructs and a commercial product in a model of abdominal full thickness defect repair. To prepare the bioengineered construct, collagen type 1 from porcine skin was isolated using an acid solubilization method. After purification, the collagen was formed into collagen sheets that were physically bonded to form a mechanically robust construct that was subsequently laser micropatterned with pores as a means to promote tissue integration (collagen only construct). A second engineered construct consisted of the aforementioned collagen construct embedded in an RGD-functionalized alginate gel that serves as a bioactive interface (collagen-alginate construct). The commercial product is a biologic mesh derived from bovine pericardium (Veritas^® ). We observed enhanced vascularization in the midportion of the engineered collagen-alginate construct 2 weeks after implantation. Overall, the performance of the bioengineered constructs was similar to that of the commercial product with comparable integration strength at 8 weeks. Bioengineered constructs derived from monomeric collagen demonstrate promise for a variety of load bearing applications in tissue engineering. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2345-2354, 2018.

Characteristics of different mesh types for abdominal wall repair in an experimental model of peritonitis

BACKGROUND

The use of synthetic mesh to repair a potentially contaminated incisional hernia may lead to higher failure rates. A biological mesh might be considered, but little is known about long-term results. Both biological and synthetic meshes were investigated in an experimental model of peritonitis to assess their characteristics in vivo.

METHODS

Male Wistar rats were randomized into five groups and peritonitis was induced. A mesh was implanted after 24 h. Five meshes were investigated: Permacol™ (cross-linked collagen), Strattice™ (non-cross-linked collagen), XCM Biologic^® (non-cross-linked collagen), Omyra^® Mesh (condensed polytetrafluoroethylene) and Parietene™ (polypropylene). The rats were killed after either 30, 90 or 180 days. Incorporation and shrinkage of the mesh, adhesion coverage, strength of adhesions and histology were analysed.

RESULTS

Of 135 rats randomized, 18 died from peritonitis. Some 180 days after implantation, both XCM Biologic^® and Permacol™ had significantly better incorporation than Strattice™ (P = 0·003 and P = 0·009 respectively). Strattice™ had significantly fewer adhesions than XCM Biologic^® (P = 0·001) and Permacol™ (P = 0·020). Thirty days after implantation, Permacol™ had significantly stronger adhesions than Strattice™ (P < 0·001). Shrinkage was most prominent in XCM Biologic^® , but no significant difference was found compared with the other meshes. Histological analysis revealed marked differences in foreign body response among all meshes.

CONCLUSION

This experimental study suggested that XCM Biologic^® was superior in terms of incorporation, macroscopic mesh infection, and histological parameters such as collagen deposition and neovascularization. There must be sufficient overlap of mesh during placement, as XCM Biologic^® showed a high rate of shrinkage. Surgical relevance The use of synthetic mesh to repair a potentially contaminated incisional hernia is not supported unequivocally, and may lead to a higher failure rate. A biological mesh might be considered as an alternative. There are few long-term studies, as these meshes are expensive and rarely used. This study evaluated the use of biological mesh in a contaminated environment, and investigated whether there is an ideal mesh. A new non-cross-linked biological mesh (XCM Biologic^® ) was evaluated in this experiment. The new non-cross-linked biological mesh XCM Biologic^® performed best and may be useful in patients with a potentially contaminated incisional hernia.

2017 update of the WSES guidelines for emergency repair of complicated abdominal wall hernias

Emergency repair of complicated abdominal wall hernias may be associated with worsen outcome and a significant rate of postoperative complications. There is no consensus on management of complicated abdominal hernias. The main matter of debate is about the use of mesh in case of intestinal resection and the type of mesh to be used. Wound infection is the most common complication encountered and represents an immense burden especially in the presence of a mesh. The recurrence rate is an important topic that influences the final outcome. A World Society of Emergency Surgery (WSES) Consensus Conference was held in Bergamo in July 2013 with the aim to define recommendations for emergency repair of abdominal wall hernias in adults. This document represents the executive summary of the consensus conference approved by a WSES expert panel. In 2016, the guidelines have been revised and updated according to the most recent available literature.

Post-incisional ventral hernia repair in patients undergoing chemotherapy: improving outcomes with biological mesh

Background

Patients requiring ventral hernia (VH) repair during perioperative chemotherapy have a higher risk for post-operative complications. The aim of the study was to perform a case-controlled analysis in patients undergoing chemotherapy who underwent VH repair using biological mesh or synthetic mesh.

Methods

From January 2013 to December 2015, 32 patients, within 8 weeks from chemotherapy administration, were treated electively for VH repair using a biological mesh (BIOMESH). A control group (CG) receiving chemotherapy within the same time interval and treated with synthetic meshes was selected. There were no differences regarding sex, age, American Society of Anesthesiologists (ASA) score III, BMI, and size of the defect. Morbidity, type of complications, and recurrence rate were investigated and compared between the two groups.

Results

In the BIOMESH group, eight patients (25 %) experienced complications. Wound dehiscence occurred in four (12.5 %) patients and was treated conservatively. Only three small seromas not requiring treatment were observed. The CG presented a higher mean Clavien-Dindo complication grade (1.94 ± 0.44 vs 1.63 ± 0.52; p = 0.13) and a higher incidence of wound dehiscence (n = 9/32, 28.1 % vs n = 4/32, 12.5 %; p = 0.11). Five patients developed seroma treated by wound drainage. One patient experienced an intra-abdominal collection treated by percutaneous drainage. At the univariate and multivariate analysis use of traditional mesh, BMI and the ASA III were predictive factors of post-operative complications. Two patients (6.3 %) developed a VH recurrence only in the CG.

Conclusions

Biological meshes could be considered a valid option to improve post-operative short-term outcomes in selected high-risk patients undergoing chemotherapy treated for VH repair.

Long-term outcomes of sandwich ventral hernia repair paired with hybrid vacuum-assisted closure

BACKGROUND

Sandwich ventral hernia repair (SVHR) may reduce ventral hernia recurrence rates, although with an increased risk of surgical site occurrences (SSOs) and surgical site infections (SSIs). Previously, we found that a modified negative pressure wound therapy (hybrid vacuum-assisted closure [HVAC]) system reduced SSOs and SSIs after ventral hernia repair. We aimed to describe our outcomes after SVHR paired with HVAC closure.

METHODS

We conducted a 4-y retrospective review of all complex SVHRs (biologic mesh underlay and synthetic mesh overlay) with HVAC closure performed at our institution by a single surgeon. All patients had fascial defects that could not be reapproximated primarily using anterior component separation. Descriptive statistics were used to report the incidence of postoperative complications and hernia recurrence.

RESULTS

A total of 60 patients (59.3 ± 11.4 y, 58.3% male, 75% American Society of Anesthesiologists class ≥3) with complex ventral hernias being underwent sandwich repair with HVAC closure. Major postoperative morbidity (Dindo-Clavien class ≥3) occurred in 14 (23.3%) patients, but incidence of SSO (n = 13, 21.7%) and SSI (n = 4, 6.7%) was low compared with historical reports. Median follow-up time for all patients was 12 mo (interquartile range 5.8-26.5 mo). Hernia recurrence occurred in eight patients (13.3%) after a median time of 20.6 months (interquartile range 16.4- 25.4 months).

CONCLUSIONS

Use of a dual layer sandwich repair for complex abdominal wall reconstruction is associated with low rates of hernia recurrence at 1 year postoperatively. The addition of the HVAC closure system may reduce the risk of SSOs and SSIs previously reported with this technique and deserves consideration in future prospective studies assessing optimization of ventral hernia repair approaches.

Development and preparation of a low-immunogenicity porcine dermal scaffold and its biocompatibility assessment

Acellular dermal matrix (ADM) has been widely used in repair and reconstruction of tissue defect. Therapeutic effect of porcine ADM (PADM) is inferior to that of human ADM (HADM). Relatively high immunogenicity and the resulting strong inflammatory response are major issue in application of PADM. We therefore treated reticular layer PADM (Rl-PADM) with matrix metalloproteinase-7 (MMP-7) and obtained a low-immunogenicity porcine dermal scaffold (LIPDS). Highly immunogenic components, tissue structure, cytocompatibility, and postgrafting histological changes of LIPDS were further investigated. Compared with Rl-PADM, LIPDS showed that the epithelial root sheath, cell debris, laminin, and type IV collagen were almost entirely removed, the structure remained normal, and the interfibrous space was relatively enlarged. Cytocompatibility of LIPDS was similar to that of HADM but superior to Rl-PADM. With regard to the extent of tissue ingrowth in terms of host fibroblasts infiltration and vascularization, LIPDS exhibited clear advantages over Rl-PADM after they had been subcutaneously transplanted in a rat model. In addition, no excessive inflammatory response was observed in LIPDS group up to 28 days postgraft, and the morphosis of collagenous fibers kept essentially normal. However, there were stronger inflammatory response and obvious collagen spallation in Rl-PADM group. The processes of integration and remodeling after the LIPDS grafting were similar to those of a normal wound healing response. The LIPDS graft was vascularized at a relatively high speed. Thus, as an implantable scaffold material, LIPDS is a superior template for guiding tissue regeneration and remodeling.

Recent advances in acellular regenerative tissue scaffolds

The management of chronic wounds is a considerable challenge for foot and ankle surgeons. The well-established tenets of adequate vascular supply, debridement with eradication of infection, and offloading must be employed in the management of all extremity wounds. Regenerative scaffolds are a viable means of reestablishing a favorable wound environment. The matrix facilitates cell migration, chemoattraction, angiogenesis, wound bed granulation, and expedited wound closure. Although studies have demonstrated success with acellular matrices, a multimodal approach should always be employed to improve healing success. Negative pressure wound therapy, compression, offloading, and antibiotics are advocated to improve outcomes. Acellular graft selection requires a multifactorial analysis, taking into consideration the specific patient and wound characteristics as well as the differences between acellular matrices. Patient age, comorbidities, activity level, and ability to comply with protocol as well as wound etiology, duration, depth, surface area, exudate, bacterial burden, location, vascular status, ischemic status, and presentation are all critical components. To effectively choose a matrix, the clinician must have a comprehensive understanding of the products available and the data validating their use. The mechanisms by which the acellular matrix accelerates wound healing and increases the likelihood of wound healing continue to be investigated. However, it is clear that these acellular biologic tissue scaffolds are incorporating into the host tissue, with resultant revascularization and cellular repopulation. Moving forward, additional investigations examining the effectiveness of acellular biologic tissue scaffolds to improve healing in complex, nondiabetic wounds are warranted.

A systematic review of the surgical treatment of large incisional hernia

PURPOSE

Incisional hernia (IH) is one of the most frequent postoperative complications. Of all patients undergoing IH repair, a vast amount have a hernia which can be defined as a large incisional hernia (LIH). The aim of this study is to identify the preferred technique for LIH repair.

METHODS

A systematic review of the literature was performed and studies describing patients with IH with a diameter of 10 cm or a surface of 100 cm2 or more were included. Recurrence hazards per year were calculated for all techniques using a generalized linear model.

RESULTS

Fifty-five articles were included, containing 3,945 LIH repairs. Mesh reinforced techniques displayed better recurrence rates and hazards than techniques without mesh reinforcement. Of all the mesh techniques, sublay repair, sandwich technique with sublay mesh and aponeuroplasty with intraperitoneal mesh displayed the best results (recurrence rates of <3.6%, recurrence hazard <0.5% per year). Wound complications were frequent and most often seen after complex LIH repair.

CONCLUSIONS

The use of mesh during LIH repair displayed the best recurrence rates and hazards. If possible mesh in sublay position should be used in cases of LIH repair.

Matching biological mesh and negative pressure wound therapy in reconstructing an open abdomen defect

Reconstruction of open abdominal defects is a clinical problem which general and plastic surgeons have to address in cooperation. We report the case of a 66-year-old man who presented an abdominal dehiscence after multiple laparotomies for a sigmoid-rectal adenocarcinoma that infiltrated into the abdominal wall, subsequently complicated by peritonitis and enteric fistula. A cutaneous dehiscence and an incontinent abdominal wall resulted after the last surgery. The abdominal wall was reconstructed using a biological porcine cross-linked mesh Permacol (Covidien Inc., Norwalk, CT). Negative Pressure Wound Therapy (NPWT), instead, was used on the mesh in order to reduce wound dimensions, promote granulation tissue formation, and obtain secondary closure of cutaneous dehiscence which was finally achieved with a split-thickness skin graft. Biological mesh behaved like a scaffold for the granulation tissue that was stimulated by the negative pressure. The biological mesh was rapidly integrated in the abdominal wall restoring abdominal wall continence, while the small dehiscence, still present in the central area, was subsequently covered with a split-thickness skin graft. The combination of these different procedures led us to solve this complicated case obtaining complete wound closure after less than 2 months.

Evaluation of a porcine dermal collagen (permacol) implant for abdominal wall reconstruction in a pediatric multitrauma patient

The presence of a contaminated surgical field in abdominal wall defects caused by trauma presents a challenge for surgeons. Both primary suture and synthetic meshes are strongly discouraged as surgical treatments in such cases. We describe the use of a porcine dermal collagen (Permacol) implant in an eight-year-old patient with multiple injuries. Three months after discharge, the child remains well with good cosmetic results. He is free of pain and has returned to full activity levels with complete wound closure and without any evidence of residual hernia. In conclusion, our experience indicates that the use of Permacol can be considered an efficient technique for reconstructing an infected abdominal wall defect of a pediatric multitrauma patient.

WSES guidelines for emergency repair of complicated abdominal wall hernias

Emergency repair of complicated abdominal hernias is associated with poor prognosis and a high rate of post-operative complications.A World Society of Emergency Surgery (WSES) Consensus Conference was held in Bergamo in July 2013, during the 2nd Congress of the World Society of Emergency Surgery with the goal of defining recommendations for emergency repair of abdominal wall hernias in adults. This document represents the executive summary of the consensus conference approved by a WSES expert panel.

Long-term outcomes (>5-year follow-up) with porcine acellular dermal matrix (Permacol) in incisional hernias at risk for infection

PURPOSE

We reviewed retrospectively all patients undergoing abdominal wall reconstruction using porcine acellular dermal matrix (PADM) from 2004 to 2008 with follow-up assessment in 2012. Technique, short-term (infection, seroma, wound dehiscence), and long-term (mesh infection, recurrence) complications, and hernia recurrences were evaluated by physician examination ≥5 years postoperatively.

RESULTS

56 patients at high risk for infection had elective operation; nine had non-elective operation for complications of prior incisional hernia/hernia repair. Operations were clean, clean-contaminated, contaminated, or grossly infected in 49, 32, 12, and 6%, respectively. Techniques of repair included 10 onlay (six reinforced primary closures, four bridging patches), 47 sublay (20 reinforced primary closures, 27 bridging patches), six inlay, and two sandwich (sublay and onlay). Early complications (≤30 days postoperatively) occurred in 19 of the 65 patients (29%), including two prosthetic dehiscences from fascial attachment, 13 wound infections, and 4 seromas. After a mean follow-up of ≥5 years in 59 of 65 patients, physician-reported incidences of infection requiring removal of mesh or hernia recurrence were 25 and 66%, respectively. Hernia recurrence occurred in 12 of 26 (46%) patients with a reinforced repair and 27 of 33 (82%) with patched repairs. Mesh infection occurred in 7 of 24 patients with sublay patch and in 4 of 19 sublay reinforcement. The greatest recurrence rate was in contaminated (71%) and grossly infected wounds (100%), while recurrence rate was 63% in clean and 63% in clean-contaminated wounds.

CONCLUSIONS

At ≥5 years of follow-up, use of PADM as a bioprosthesis in ventral hernia in high-risk patients is unreliable as a definitive repair in the majority of patients, but may provide satisfactory outcomes in some patients.

Outcome of Abdominal Wall Hernia Repair with Permacol™ Biologic Mesh

The use of biologic mesh in abdominal wall operations has gained popularity despite a paucity of outcome data. We aimed to review the experience of a large healthcare organization with Permacol™. A retrospective study was conducted of patients who underwent abdominal hernia repair with Permacol™ in 14 Southern California hospitals. One hundred ninety-five patients were analyzed over a 4-year period. Operations included ventral/incisional hernia repairs, ostomy closures, parastomal hernia repairs, and inguinal hernia repairs. In 50 per cent of the patients, Permacol™ was used to reinforce a primary fascial repair and in 50 per cent as a fascial bridge. The overall complication rate was 39.5 per cent. The complication rate was higher in patients with infected versus clean wounds, body mass index (BMI) 40 kg/m2 or greater versus BMI less than 40 kg/m2, in patients with prior mesh repair, and when mesh was used as a fascial bridge. With a mean follow-up of 2.1 years, morbid obesity was associated with a higher recurrence. To date this is the largest study on the use of Permacol™ in abdominal wall hernia repair. In our patient population undergoing heterogeneous operations with a majority of wounds as Class II or higher, use of Permacol™ did not eliminate wound morbidity or prevent recurrence, especially in morbidly obese patients.

The Effectiveness of Porcine Dermal Collagen (Permacol(®)) on Wound Healing in the Rat Model

Porcine acellular dermal collagen (PDC), which is a biological material derived from processing porcine dermis, has already been used for urologic, gynecologic, plastic, and general surgery procedures up to now. The aim of this study is to investigate the effectiveness of PDC on wound healing as a dermal substitute in the rat model. Twenty Wistar albino rats were divided into two groups. Standard full-thickness skin defects were created on the back of the rats. In the control group (Group 1), the dressings moisturized with saline were changed daily. In the study group (Group 2), porcine dermal collagen was implanted onto each wound and fixed with 4-0 polypropylene sutures. Contraction percentages of wound areas were calculated on the third, seventh, tenth, and fourteenth days by using the planimetric program. On fourteenth day, the wound areas were excised for histopathological examination, inflammatory scoring, and evaluation of collagen deposition. The study group was superior to the control group in terms of inflammatory scoring, type I/type III collagen ratio, and wound contraction rates. Porcine dermal collagen may be used effectively and safely on full-thickness wounds as a current dermal substitute.

The role of biologic mesh in abdominal wall reconstruction: a systematic review of the current literature

BACKGROUND

Biologic mesh in the form of allograft or xenograft products have been used in complicated abdominal hernia repair, but few comparative studies exist.

METHODS

A systematic review of original incisional hernia studies was conducted to include 2 primary end points: hernia recurrence and surgical site occurrence. Analysis of variance and a Satterthwaite t test compared the devices.

RESULTS

Twenty-nine studies were included in this analysis, which included 1,257 patients. The total number of studies and the total subjects for each device include the following: Permacol (Tissue Science Laboratories, Hampshire, UK) (4/64), Surgisis (Cook Medical, Bloomington, IN) (3/87), and Alloderm (LifeCell, Corp, Branchburg, NJ) (23/1,106). Device-specific recurrence rates and surgical site occurrence rates, respectively, were as follows: Alloderm (20.8%, 31.4%), Permacol (10.9%, 25%), and Surgisis (8.0%, 40.2%). A Satterthwaite t test comparison revealed significantly higher numbers of hernia recurrence (P = .006) and surgical site occurrence (P = .04) when comparing Alloderm with Permacol.

CONCLUSIONS

Biologic mesh does play a beneficial role in abdominal wall reconstruction although allograft acellular dermal matrix does have a higher recurrence rate as compared with xenograft products, which limits its current role in hernia repair.

Biologic grafts for ventral hernia repair: a systematic review

BACKGROUND

Biologic grafts hold promise of a durable repair for ventral hernias with the potential for fewer complications than synthetic mesh. This systematic review was performed to evaluate the effectiveness and safety of biologic grafts for ventral hernia repair.

METHODS

MEDLINE, Embase, and Cochrane Central Register of Controlled Trials were searched for studies on biologic grafts for the repair of ventral hernias. Outcomes are presented as weighted pooled proportions.

RESULTS

Twenty-five retrospective studies were included. Recurrence depended on wound class, with an overall rate of 13.8% (95% confidence interval [CI], 7.6-21.3). The recurrence rate in contaminated/dirty repairs was 23.1% (95% CI, 11.3-37.6). Abdominal wall laxity occurred in 10.5% (95% CI, 3.7-20.3) of patients. The surgical morbidity rate was 46.3% (95% CI, 33.3-59.6). Infection occurred in 15.9% (95% CI, 9.8-23.2) of patients but only led to graft removal in 4.9% of cases.

CONCLUSIONS

No randomized trials are available to properly evaluate biologic grafts for ventral hernia repair. The current evidence suggests that biologic grafts perform similarly to other surgical options. Biologic grafts are associated with a high salvage rate when faced with infection.

A review of available prosthetic material for abdominal wall repair

Abdominal wall incisional and inguinal hernia repair can call for utilization of implants or prostheses as an alternative to simple suture techniques. The various implants can be synthetic, biologic or mixed: their physicochemical properties condition the mechanical results and the long-term outcome of the repair. The increasing number of available materials allows the surgeon to choose between a wide variety depending on the indication, the site of implantation, the surgical approach and whether the operative field is contaminated or not. With regard to evidence-based medicine, while several synthetic implants have been shown to be superior in efficacy to simple suture, other studies are underway to develop the indications for bioprostheses, in particular in contaminated fields. This review of the literature summarizes the current knowledge on synthetic and biologic implants (physicochemical characteristics, forms, indications).

Repair of incisional hernias with biological prosthesis: a systematic review of current evidence

BACKGROUND

No consensus has been reached on the use of bioprosthetics to repair abdominal wall defects. The purpose of this systematic review was to summarize the outcomes from studies describing this use of various bioprosthetics for incisional hernia repair.

METHODS

Studies published by October 2011 were identified through literature searches using EMBASE, MEDLINE, and the Cochrane Central Register of Controlled Trials.

RESULTS

A total of 491 articles were scanned, 60 met eligibility criteria. Most studies were retrospective case studies. The studies ranged considerably in methodologic quality, with a modified Methodological Index of Nonrandomized Studies score from 5 to 12. Many repairs were performed in contaminated surgical sites (47.9%). At least one complication was seen in 87% of repairs. Major complications noted were wound infections (16.9%) and seroma (12.0%). With a mean follow-up period of 13.6 months the hernia recurrence rate was 15.2%.

CONCLUSIONS

There is an insufficient level of high-quality evidence in the literature on the value of bioprosthetics for incisional hernia repair. Randomized controlled trials that use standardized reporting comparing bioprosthetics with synthetic mesh for incisional hernia repair are needed.

Abdominal wall reconstruction using a non-cross-linked porcine dermal scaffold: a follow-up study

PURPOSE

In a previous study, we have shown that non-cross-linked porcine dermal scaffolds (NCPDS) are a safe and effective alternative to prosthetic mesh in the reconstruction of complicated abdominal wall defects. Here, we report the long-term outcomes of abdominal wall reconstruction using NCPDS in a larger patient population.

METHODS

Patients who underwent abdominal wall reconstruction with NCPDS between May 2006 and December 2010 were retrospectively reviewed. Analysis of demographics, indications for NCPDS placement, surgical technique, complications, and follow-up data was performed.

RESULTS

NCPDS was used for abdominal wall repair in 40 patients. In all patients, NCPDS was positioned using an intraperitoneal technique. At a mean follow-up time of 40.1 months, most patients had successful outcomes. Complications included seroma (21 %), recurrence (7.9 %), and infection (5.2 %); these rates are comparable to our initial report. Two patients died from multi-organ failure unrelated to NCPDS placement.

CONCLUSIONS

This study shows that complex abdominal wall defects can be successfully reconstructed using NCPDS with a low rate of recurrence and complications.

Use of permacol in parietal and general surgery: a bibliographic review

BACKGROUND

The use of synthetic meshes on infected incisional hernias often fails and is therefore contraindicated. Biological meshes offer a novel solution. Among them, Permacol requires a bibliographic analysis of its efficacy and tolerance.

DESIGN

A bibliographic analysis was carried out on the efficacy and tolerance of Permacol in parietal and general surgery.

RESULTS

A total of 22 publications described the use of Permacol in digestive surgery. The advantages of Permacol would be usability in contaminated surgical fields, biocompatibility, no erosion of intestinal wall, and less risk of adhesions. The main drawback of Permacol is its high cost.

CONCLUSION

Even so, Permacol can play an important part in the short-term management of complex or contaminated abdominal wall defects. The lack of long-term studies and the high cost of the implant call for a medical cost-effectiveness assessment to determine the indications for Permacol in parietal and general surgery.

Biological meshes: a review of their use in abdominal wall hernia repairs

PURPOSE

Biological meshes are mostly used in infected fields within complex abdominal wall hernia repairs. There is no consensus, however, on the most appropriate material to be used in a given situation.

METHODS

A literature review of published articles reporting the utilization of biological meshes in ventral/incisional hernia repair was conducted. Data were analyzed to compare the recurrence rates obtained with biological meshes.

MAIN FINDINGS

Only a few prospective comparative studies were identified. Most publications relate to AlloDerm®, Permacol™ and Surgisis™ with data from other meshes insufficient to draw conclusions. AlloDerm has a 0-100% recurrence rate among studies. It compares poorly with Surgisis and results in an unfavorable outcome when used as a 'bridge prosthesis'. Permacol has consistent recurrence rates of 0-15%, whatever the patients' profiles or the context of infected fields, when considering the most relevant studies. The Surgisis results are more conflicting: the mesh exhibits low recurrence rates in clean fields, but in infected fields the recurrence rate is up to 39%.

CONCLUSION

Taken together, these studies suggest that the cross-linked mesh, Permacol has the lowest failure rate and the longest time to failure, particularly in contaminated or infected fields. However, this data should be confirmed by large prospective randomized studies.

Dynamic Magnetic Resonance Imaging Demonstrates the Integrity of Perineal Reconstruction following Cylindrical Abdominoperineal Excision with Reconstruction of the Pelvic Floor Using Porcine Collagen

A 72-year-old female presented with a six-month history of increased frequency of defecation, rectal bleeding, and severe rectal pain. Digital rectal examination and endoscopy revealed a low rectal lesion lying anteriorly. This was confirmed histologically as adenocarcinoma. Radiological staging was consistent with a T₃N₂ rectal tumour. Following long-course chemoradiotherapy repeat staging did not identify any metastatic disease. She underwent a laparoscopic cylindrical abdominoperineal excision with en bloc resection of the coccyx and posterior wall of the vagina with a negative circumferential resection margin. The perineal defect was reconstructed with Permacol (biological implant, Covidien) mesh. She had no clinical evidence of a perineal hernia at serial followup. Dynamic MRI images of the pelvic floor obtained during valsalva at 10 months revealed an intact pelvic floor. A control case that had undergone a conventional abdominoperineal excision with primary perineal closure without clinical evidence of herniation was also imaged. This confirmed subclinical perineal herniation with significant downward migration of the bowel and bladder below the pubococcygeal line. We eagerly await further evidence supporting a role for dynamic MR imaging in assessing the integrity of a reconstructed pelvic floor following cylindrical abdominoperineal excision.

Durability of biologic implants for use in hernia repair: a review

In the past 10 years, hernia repair has evolved from primarily using suture closure to using mesh repair. Synthetic mesh implants were the initial gold standard, but the rate of complications such as infection, adhesions, and erosion was higher with synthetics than has been observed with newer biologic implants. As efforts to develop the ideal implant continue, the advantages of biologics for hernia and other soft-tissue repair become increasingly apparent. Animal-sourced biologics have the potential advantage over human dermis of being more amenable to standardization, and porcine dermal collagen architecture closely resembles that of human dermis. Cross-linking the collagen adds strength and durability to the implant that facilitates healing of surgical wounds, just as endogenous collagen, which is cross-linked, has innate durability that enhances natural wound healing. This review defines and assesses durability of the acellular collagen (biologic) implant options available for hernia repair. The factors that affect wound healing-and hernia repair--are summarized. Additionally, the particular features that enhance durability are described, and durability-related clinical outcomes discussed in the literature are cited to aid clinicians in making informed surgical choices.

Abdominal wall reconstruction in patients with digestive tract fistulas

Abdominal wall reconstruction in the digestive tract fistula patient is a complex issue. The authors review the available data and present information regarding the timing of surgery, techniques of abdominal wall reconstruction, hernia repair, and discuss pitfalls associated with the various options. A simple and basic approach to this problem is described.

Evaluation of crosslinked and non-crosslinked biologic prostheses for abdominal hernia repair

Introduction

Abdominal wall defects and incisional hernias represent a challenging problem. Currently, several commercially available biologic prostheses are used clinically for hernia repair. We compared the performance and efficacy of two non-crosslinked meshes in ventral hernia repair to two crosslinked prostheses in a rodent model.

Methods

Animals were divided into 12 groups (4 matrix types and 3 termination time-points per matrix). A ventral defect was carefully created and overlapped with the biologic prosthesis.

Results

Major complications were seroma induction (3 mesh types), implant extrusion (1 mesh type), severe inflammatory and immune responses (non-crosslinked mesh), fibrosis and mineralisation (3 mesh types). After inflammation resolution, 3 of the matrices tested supported hernia healing but with marked tissue and temporal differences. AlloDerm^®* and Surgisis Gold™ showed tissue reactivity with the host and a rapid rate of matrix remodelling. Bard CollaMend™^* Implant proved to be inept for hernia repair under the conditions tested. Permacol™ biological implant integration with host tissue increased over time, supporting hernia healing with strength of tissue, and appears to be a safe prosthetic material for ventral hernia repair based on the results of this rodent study.

Abdominal ventral hernia repair with current biological prostheses: an experimental large animal model

Biologic prostheses have emerged to address the limitations of synthetic materials for ventral hernia repairs; however, they lack experimental comparative data. Fifteen swine were randomly assigned to 1 of 3 bioprosthetic groups (DermaMatrix, AlloDerm, and Permacol) after creation of a full thickness ventral fascial defect. At 15 weeks, host incorporation, hernia recurrence, adhesion formation, neovascularization, inflammation, and biomechanical properties were assessed. No animals had hernia recurrence or eventration. DermaMatrix and Alloderm implants demonstrated more adhesions, greater inflammatory infiltration, and more longitudinal laxity, but near identical neovascularization and tensile strength to Permacol. We found that porcine acellular dermal products (Permacol) contain following essential properties of an ideal ventral hernia repair material: low inflammation, less elastin and stretch, lower adhesion rates and cost, and more contracture. The addition of lower cost xenogeneic acellular dermal products to the repertoire of available acellular dermal products demonstrates promise, but requires long-term clinical studies to verify advantages and efficacy.

Repair of large abdominal incisional hernia by reconstructing the midline and use of an onlay of biological material

BACKGROUND

The aim of this study was to determine the feasibility and efficacy of repairing large abdominal incisional hernias by reconstructing the midline using bilateral abdominis rectus muscle sheath (ARS) relaxing incisions and a biological material onlay.

METHODS

Between January 2002 and December 2008, 71 patients underwent repair of large incisional hernias at 2 community hospitals. After replacement of hernia sac contents into the peritoneal cavity, a relaxing incision was made in the ARS bilaterally. Then, the midline was closed primarily. The biological material was used as an onlay and sutured to the lateral edges of the relaxed ARS. Main outcome measures were postoperative complications and hernia recurrence.

RESULTS

Median defect size was 195 cm(2) (range, 150-420 cm(2)), median surgical time was 125 minutes, and median hospital stay was 6 days. There were no deaths and no wound infections. Wound seroma, the most frequent postoperative complication, occurred in 51 (72%) of the 71 patients. There was 1 (1.4%) recurrence.

CONCLUSIONS

In these 71 patients, our technique for repair of large abdominal incisional hernias was safe and effective.

Not all biologics are equal!

BACKGROUND

Although the efficacy of various biologic meshes in the abdominal reconstruction of complex ventral hernia has been shown, the performance profile of various biologic mesh scaffolds in terms of hernia-specific outcomes such as recurrence, mesh explantation, and mesh infections has not been examined.

AIM

To evaluate the clinical outcomes of patients who underwent complex ventral hernia repair with bioprosthetic material.

METHODS

This study is a retrospective analysis of the use of bioprosthetic material in complex ventral hernia at an academic institution from January 2002 to December 2007.

RESULTS

A total of 58 patients with a mean age of 57.2 years and mean body mass index (BMI) of 33.8 who underwent reconstruction of ventral abdominal defects with a bioprosthetic from January 2002 to February 2009 were included in the study. The study patients had about 4.8 previous surgeries and 43.1% of patients had reconstruction in a setting of enterocutaneous fistula, while 46.6% had a previous mesh infection. Complex ventral hernia was seen in 50 patients, while eight patients had ventral and parastomal hernia. The type of biologic used for reconstruction was human-derived (AlloDerm, 29), porcine cross-linked (CollaMend, 3; Permacol, 2), and non-cross-linked porcine (Surgisis, 16; Strattice, 8). At least one complication was seen in 72.4% of patients. Major complications noted were surgical wound infections (19.0%), seroma (8.6%), and abscess formation (5.2%). The one-year hernia recurrence rate was 27.9% and mesh explantation was needed in 17.2% of patients. AlloDerm was less likely to be explanted (13.8%) or become infected (37.9%) but more likely to recur (28.6%) compared to porcine cross-linked bioprosthesis. Porcine cross-linked biologics were more likely to become infected (60%) and explanted (40%) but less likely to recur (20%) compared to AlloDerm. Non-cross-linked porcine biologics were less likely to be explanted (16.7%) but had higher recurrence (29.4%) compared to cross-linked porcine biologics and a higher infection rate (54.2%) compared to AlloDerm.

CONCLUSIONS

The results from this study underscore the difficulty of repairing complex abdominal wall defects in contaminated fields. Cross-linked porcine biologics showed relatively higher infection and explantation rates. Equivalent recurrence and explantation rates were observed for the non-cross-linked porcine biologics and AlloDerm. These data indicate that there is currently no ideal biologic for complex ventral hernia repair.

Biological Mesh in Hernia Repair, Abdominal Wall Defects, and Reconstruction and Treatment of Pelvic Organ Prolapse: A Review of the Clinical Evidence

The use of biological meshes seems to be an innovation that influences all surgical fields. The existing evidence indicates that biological meshes cannot only be applied on the area of hernia repair, but also on cases of abdominal reconstruction and pelvic organ prolapse treatment, especially in the presence of contaminated or potentially contaminated surgical fields. Low risks of graft rejection, complications, and infection seem to be the main advantages of biological meshes in comparison with the synthetic nonabsorbable ones. Nevertheless, the elevated costs suggest that biological mesh implantation should be evaluated in correlation to the needs of each clinical case.

[Abdominal wall closure by incisional hernia and herniation after laparostoma]

As hernias and abdominal wall defects have a variety of etiologies each with its own complications and comorbidities in various constellations, efficient treatment requires patient-oriented management. There is no recommended standard treatment and the very different clinical pictures demand an individualized interdisciplinary approach. Particularly in the case of complicated hernias, the planning of the operation should focus on the problems posed by the individual patient. Treatment mainly depends on the etiology of the hernia, immediate or long-term complications and the efficiency of individual repair techniques. Abdominal wall repair for recurrent herniation requires direct closure of the fascia generally using the sublay technique with a lightweight mesh. It is still unclear whether persistent inflammation, mesh dislocation, fistula formation or other long-term complications are due to certain materials or to the surgical technique. With mesh infections it has been shown to be advantageous to remove a polytetrafluoroethylene (PTFE) mesh, while the combination of systemic and local treatment appears to suffice for a polypropylene or polyester mesh. Heavier meshes in the sublay position or plastic reconstruction with autologous tissue are indicated as substitutes for the abdominal wall for giant hernias, repeated recurrences and large abdominal wall defects. A laparostoma is increasingly more often created to treat septic intra-abdominal processes but is very often responsible for a complicated hernia. If primary repair of the abdominal wall is not an option, resorbable material or split skin is used for coverage under the auspices of a planned hernia repair.

Porcine dermal collagen (Permacol) for chest and abdominal wall reconstruction in thoraco-omphalopagus conjoined twin separation

Each set of conjoined twins presents a unique challenge, which centers on the ability to separate and if necessary reconstruct shared organs and to achieve subsequent skin cover of the often very large residual defect after completion of the separation. This report describes the use of a bioprosthetic Permacol derived from porcine dermal collagen to reconstruct the chest and abdominal wall.

Long-term histologic and mechanical results of a Permacol™ abdominal wall explant

PURPOSE

We hypothesize that Permacol™ may allow controlled integration over time while providing long-term mechanical stability and native tissue remodeling. The purpose of this report is to investigate these properties in an explanted piece of Permacol™ after 2 years in vivo.

METHODS

A 62-year-old female presented with a complex abdominal wall history having undergone a transverse rectus abdominis musculocutaneous (TRAM) flap breast reconstruction 10 years ago, followed by an abdominal wall repair with Marlex™ mesh for weakness 3 years later. Two years ago, she developed an abdominal bulge repaired with a Permacol™ overlay. Twenty-three months postoperatively, she presented with abdominal distension. Computed tomography (CT) scanning demonstrated a fluid collection behind the Permacol™. She underwent incision and drainage of the hematoma/bursa and quilting repair of the abdominal wall. A 1 × 6-cm Permacol™ section was resected as part of closure. Histology, immunohistochemistry, and mechanical testing of the Permacol™ explant were performed.

RESULTS

Histology showed fibroblast and blood vessel ingrowth with no cellular infiltrates reflective of inflammation. Immunohistochemistry for human-specific collagen types I and III and elastin detected staining throughout. Sections stained with non-specific control antibody exhibited no discernable staining. Elastin highlighted blood vessels. Native Permacol™ had a breaking strength of ~20 N, while for explanted Permacol™, it was ~33 N.

CONCLUSIONS

Permacol™ maintained durability while allowing vascular ingrowth without residual inflammation. Explant demonstrated integration with human collagen and elastin remodeling throughout. Increase in mechanical strength may reflect newly synthesized collagen and elastin. These histologic findings and clinical result support the use of Permacol™ in complex abdominal wall reconstruction.

Management of Complex Abdominal Wall Defects Using Acellular Porcine Dermal Collagen

Multiple techniques have been used for the repair of complex abdominal wall defects after recurrent incisional hernias with varying rates of success. Primary repair has been associated with high recurrence rates, and prosthetic mesh placement is contraindicated in contaminated surgical fields. The development of biologic prostheses has changed the approach to these difficult problems. This study evaluates the management of complex abdominal wall defects using acellular porcine dermal collagen. Between August 2006 and May 2007, 18 patients underwent abdominal wall reconstruction for complex defects with acellular porcine dermal collagen (CollaMend™; Bard Inc., Warwick, RI). Patient demographics, preoperative risk factors, previous herniorrhaphy attempts, postoperative complications, recurrences, and long-term results were retrospectively reviewed. Records were reviewed at a mean follow up of 7.3 months; the recurrence rate was 44.4 per cent. A total of 38.9 per cent (seven of 18) developed a postoperative wound complications, including infection in 22.2 per cent (four of 18). All of the patients with infection required prosthesis removal as a result of encapsulation rather than incorporation of the biologic prosthesis. Acellular porcine dermal collagen has the potential for reconstruction of abdominal wall defects with postoperative wound occurrences comparable with other biologic materials. Encapsulation of the material was a major problem in cases with wound infection that required graft removal rather than local wound measures. Hernia recurrence and dehiscence of the graft were problems in noncompromised surgical fields.

Rejection of Permacol® mesh used in abdominal wall repair: A case report

Permacol^® mesh has shown promise when used in abdominal wall repair, especially in the presence of a contaminated surgical field. This biomaterial, derived from porcine dermis collagen, has proposed advantages over synthetic materials due to increased biocompatibility and reduced foreign body reaction within human tissues. However, we present a case report describing a patient who displayed rejection to a Permacol^® mesh when used in the repair of abdominal wound dehiscence following an emergency laparotomy. Review of the English language literature using PubMed and Medline, showed only two previously published cases of explantation of Permacol^® due to sepsis or wound breakdown. The authors believe this is the first case of severe foreign body reaction leading to rejection of Permacol^®. Both animal and human studies show conflicting evidence of biocompatibility. There are several reports of successful use of Permacol^® to repair complex incisional herniae or abdominal walls in the presence of significant contamination. It appears from the literature that Permacol^® is a promising material, but as we have demonstrated, it has the potential to evoke a foreign body reaction and rejection in certain subjects.