Histologic Analysis of Acellular Dermal Matrix in the Treatment of Anal Fistula in an Animal Model
ABSTRACT Human acellular dermal matrix (ADM) has been used successfully for the treatment of severe burns, ureter support, and abdominal wall reconstruction. This study was designed to evaluate the mechanism of ADM in the closure of anal fistula in an experimental porcine model.
The fistula-in-ano model was created in the porcine model and treated with ADM in 14 animals. Fistula specimens were obtained at hours 12 and 24 and on days 3, 7, 14, 28, 60. Hematoxylin and eosin staining, Masson trichrome staining, and immunohistochemical staining for alpha smooth muscle actin and matrix metalloproteinase 9 were performed.
The cell density increased from hour 12 to day 7 and decreased from day 7 to day 28 (p < 0.001). Mature vessels stained with alpha smooth muscle actin were identified at day 7. Alpha smooth muscle actin-positive myofibroblasts were found in clusters at the edge of the ADM at day 7. The density of vessels (p < 0.001) and myofibroblasts (p < 0.001) increased from day 7 to day 14. The density of matrix metalloproteinase 9 increased from hour 12 to day 7 and decreased from day 14 to day 60 (p < 0.001). Partially organized bundles of muscle were found by day 60.
We suggest that ADM is a reasonable new option for closure of anal fistulas. Anal fistulas begin to heal as early as 12 hours, and day 7 may be an important time point to judge whether the fistula healed preliminarily or not. The ability of ADM to become vascularized and remodeled by autologous cells may be advantageous for anal fistula healing.
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ABSTRACT: Abstract We report on a clinicopathologic study in an animal model of treatment with a new bioabsorbable polymer plug (BAPP). Over a 2-week period, 6 porcine models, which each had 4 anal fistulae, were created using Blake drains. The pigs were divided into 2 groups: the BAPP-treatment group (n = 12 fistulae) and the control group (n = 12 fistulae). Two weeks later, the pigs were humanely killed, and the perianal sites were excised and examined with gross and pathologic studies. Each fistula in the BAPP group was completely cured. In the pathologic study, the treatment sites had little disarray, few defects in the muscular layer, and small numbers of inflammatory cells. The control group had a significantly greater number of inflammatory cells and microabscesses than the BAPP group. The newly developed BAPP reduced the infection and induced good healing in anal fistulae. The BAPP may be a useful new device for the clinical treatment of anal fistulae.International surgery 05/2013; 98(2):122-128. DOI:10.9738/CC180 · 0.25 Impact Factor
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ABSTRACT: IMPORTANCE Acellular dermal matrices have many current and potential applications, but their long-term safety has not been extensively studied. In particular, limited information exists regarding such materials' resistance to infection. OBJECTIVE To assess the resistance to microbial penetration of common acellular dermal matrix materials used in reconstruction after skin cancer excision, treatment of chronic ulcers and burns, breast reconstruction, hernia repairs, and other applications. DESIGN Comparative in vitro study of 4 commercially available dermal substitutes for their ability to act as barriers to penetration by common skin pathogens. SETTING University-based dermatology and plastic surgery departments and a hospital microbiology laboratory. MATERIALS Four commercially available dermal substitutes, including AlloDerm (LifeCell), FlexHD (Musculoskeletal Transplant Foundation), Strattice (LifeCell), and NeoForm (Mentor Corporation). INTERVENTION We tested the 4 dermal matrix materials with the following 4 organisms commonly implicated in wound infections: Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pyogenes, and Candida albicans. Each material was inoculated with the same concentration of each pathogen. MAIN OUTCOME MEASURE The number of bacterial colonies grown on blood agar plates. RESULTS AlloDerm and rehydrated FlexHD were found to be the best barriers to penetration by P aeruginosa. AlloDerm, FlexHD, and Strattice also prevented penetration by S aureus and S pyogenes; NeoForm was less effective in withstanding these organisms. The results of this study were inconclusive with regard to C albicans penetration. CONCLUSIONS AND RELEVANCE Three of the 4 commonly used acellular dermal matrix materials are resistant to in vitro penetration by S aureus and S pyogenes and partially resistant to P aeruginosa. Resistance to fungal pathogens is uncertain. Antimicrobial differences across matrix materials may influence their selection for particular uses, such as treatment of refractory leg ulcers or reconstruction after skin cancer excision.02/2013; 149(5):1-5. DOI:10.1001/jamadermatol.2013.1741
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ABSTRACT: Background: Ligation of the intersphincteric fistula tract and reinforcement with a bioprosthetic graft are two recently reported procedures that showed promise in the treatment of anal fistula. This study was undertaken to validate combining ligation of the intersphincteric fistula tract plus bioprosthetic anal fistula plug and report our preliminary results and experience. Methods: 21 patients with transsphincteric anal fistulae were treated with ligation of the intersphincteric fistula tract plus concurrent bioprosthetic plug of anal fistula. We evaluated healing time, fistula closure rate, and postoperative anal function according to the Wexner continence score. Results: No mortality or major complications were observed. Median operative time was 20 (range 15-40) minutes. After a median follow-up of 14 (range 12-15) months, the overall success rate was 95% (20/21), with a median healing time of 2 (range 2-3) weeks for external anal fistula opening and 4 (range 3-7) weeks for intersphincteric groove incision. Only 1 (5%) patient reported rare incontinence for gas postoperatively (Wexner score 1). Conclusions: Ligation of the intersphincteric fistula tract plus bioprosthetic anal fistula plug is an easy, safe, effective, and useful alternative in the management of anal fistula. Further randomized controlled studies are necessary to better evaluate long-term results. © 2012 The Authors Colorectal Disease © 2012 The Association of Coloproctology of Great Britain and Ireland.Colorectal Disease 10/2012; 15(5). DOI:10.1111/codi.12062 · 2.02 Impact Factor