1 Department of General Surgery, Madigan Army Medical Center, Tacoma, Washington2 Department of Clinical Investigations, Madigan Army Medical Center, Tacoma, Washington3 Department of Pathology, Madigan Army Medical Center, Tacoma, Washington4 Department of Colorectal Surgery, Case Western Medical Center, Cleveland, Ohio
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BACKGROUND:Complications from adhesions after intra-abdominal surgery accounts for ~6% of hospital admissions. Currently, hyaluronate/carboxymethylcellulose represents the main option to prevent postoperative adhesion formation. Human amniotic membrane contains inherent anti-inflammatory properties that mitigate adhesion formation.OBJECTIVE:This study aimed to evaluate adhesion generation after surgical trauma with amniotic membranes compared with standard intraperitoneal adhesion barriers.DESIGN:This study is a double-blinded, prospective evaluation.SETTING:This study was conducted at an animal research facility.ANIMALS:Forty male rats were studied.INTERVENTION:Laparotomy was performed with peritoneal disruption to the cecum. Animals were randomly assigned to 1 of 5 groups: sham, control, saline, hyaluronic acid membrane, or amniotic membrane. Animals were euthanized at 14 days.MAIN OUTCOME MEASURES:Independent gross and histological assessments of adhesions were analyzed between groups by using adhesion scoring and microscopy. Scoring was based on the percentage of the cecum involved (0–4), vascularity of adhesions (0–3), strength (0–3), inflammation (0–3), and fibrosis (0–3). Adhered tissue was harvested for polymerase chain reaction analysis for gene regulation activity.RESULTS:All rats survived 14 days. Adhesions were observed in all animals. There were significantly fewer adhesions in the amniotic membrane group (2) versus hyaluronic acid (3) group (p = 0.01). The percentage of adhesion to the cecum was lower in the amniotic membrane group (29%) than in the hyaluronic acid group (47%, p = 0.04). Histological examination showed no significant difference between or within the 3 groups for inflammation or fibrosis. Genetic analysis of adhered tissues supported high rates of epithelialization and inhibition of fibrosis in the amniotic membrane group.LIMITATIONS:We are limited by the small sample size and the preclinical nature of the study.CONCLUSION:Human-derived amniotic membrane is effective at reducing intraperitoneal adhesion after surgical trauma and is superior to the current antiadhesion barriers. Amniotic membranes are well absorbed and demonstrate short-term safety. See Video Abstract at http://links.lww.com/DCR/A554.