Not all biologics are equal!
Department of Surgery, University of Nebraska Medical Center, 985126 Nebraska Medical Center, Omaha, NE 68198-5126, USA. Hernia
(Impact Factor: 2.05).
12/2010; 15(2):165-71. DOI: 10.1007/s10029-010-0768-7
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.
To evaluate the clinical outcomes of patients who underwent complex ventral hernia repair with bioprosthetic material.
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.
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.
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.
Available from: Swapan Ghosh
- "Potential complications at the surgical site due to infection remain a major challenge in wound healing and tissue remodeling. Infection of bioscaffold materials has been a serious problem ,  and studies have reported SIS to be susceptible to bacterial colonization and infection , . Staphylococcus aureus, a gram positive bacterium, is the primary cause of postsurgical wound infections  and therefore a major contaminant of biological scaffolds. "
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ABSTRACT: The use of biological scaffold materials for wound healing and tissue remodeling has profoundly impacted regenerative medicine and tissue engineering. The porcine-derived small intestinal submucosa (SIS) is a licensed bioscaffold material regularly used in wound and tissue repair, often in contaminated surgical fields. Complications and failures due to infection of this biomaterial have therefore been a major concern and challenge. SIS can be colonized and infected by wound-associated bacteria, particularly Staphylococcus aureus. In order to address this concern and develop novel intervention strategies, the immune microenvironment orchestrated by the combined action of S. aureus and SIS should be critically evaluated. Since the outcome of tissue remodeling is largely controlled by the local immune microenvironment, we assessed the innate immune profile in terms of cytokine/chemokine microenvironment and inflammasome-responsive genes. BALB/c mice were injected intra-peritoneally with heat-killed S. aureus in the presence or absence of SIS. Analyses of cytokines, chemokines and microarray profiling of inflammasome-related genes were done using peritoneal lavages collected 24 hours after injection. Results showed that unlike SIS, the S. aureus-SIS interactome was characterized by a Th1-biased immune profile with increased expressions of IFN-γ, IL-12 and decreased expressions of IL-4, IL-13, IL-33 and IL-6. Such modulation of the Th1/Th2 axis can greatly facilitate graft rejections. The S. aureus-SIS exposure also augmented the expressions of pro-inflammatory cytokines like IL-1β, Tnf-α, CD30L, Eotaxin and Fractalkine. This heightened inflammatory response caused by S. aureus contamination could enormously affect the biocompatibility of SIS. However, the mRNA expressions of many inflammasome-related genes like Nlrp3, Aim2, Card6 and Pycard were down-regulated by heat-killed S. aureus with or without SIS. In summary, our study explored the innate immune microenvironment induced by the combined exposure of SIS and S. aureus. These results have practical implications in developing strategies to contain infection and promote successful tissue repair.
Available from: Oskay Kaya
- "Substantial empirical evidence suggests that the use of prosthetic mesh for the closure of abdominal wall defects is associated with significantly reduced cumulative recurrence rates after short-and longterm followup. However, mesh repair of the abdominal wall defect, particularly synthetic mesh repair, is associated with several postimplantation complications, such as wound infections, mesh infections, bowel adhesions, and other complications frequently requiring revision surgery . When repairing an abdominal wall defect, a prosthetic mesh sometimes needs to be placed directly on the parietal peritoneum. "
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ABSTRACT: We present a case of immediate abdominal wall reconstruction with biologic mesh following the resection of locally advanced colonic cancer. The tumor in the right colon did not respond to neoadjuvant chemotherapy. Surgical enbloc excision, including excision of the invasion in the abdominal wall, was achieved, and the defect was reconstructed with porcine dermal collagen mesh. The patient was discharged with no complication, and adaptation of the mesh was excellent at the six-month followup.
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ABSTRACT: This research is concerned with a stability control method with a criterion based on reaction for motion control of a mobile manipulator. Mobile manipulators can propel themselves around a work area and can operate over a wide area. Then, a stability evaluation and a stability control method must be required for mobile manipulators that are not fixed on a floor. The evaluation method based on ZMP (Zero Moment Point) criterion, in which the model is regarded as a particle system, is not satisfactory for evaluating stability of a mobile manipulator that consists of solid links. In addition, transient state during tipping over has not been discussed. In this paper, we propose a stability evaluation criterion based on reaction for the solid model of a dynamic mobile manipulator. First, equations of motion of the mobile manipulator for stable and unstable states of motion are formulated based on constraint conditions. Second, a stability criterion based on reaction is proposed by referring the formulated model. Third, the relationships between changes in reaction and changes in ZMP during tipping over are discussed through simulations. Finally, it is shown that a mobile manipulator can return from unstable transient state to stable state by performing stability compensation motion.
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