Meta-Analysis of the Effects of Adhesion Barriers on Adhesion Formation in the Horse.

OBJECTIVE To determine the efficacy of adhesion barriers in horses using quantitative statistical analysis. STUDY DESIGN Meta-analytical review. METHODS A search using PubMed/MEDLINE and Google Scholar was performed, followed by secondary searches of veterinary trade journals, bibliographies of relevant articles, manufacturer websites, and technical reference guides. Randomized experimental trials in healthy horses were considered that included both a treatment and control group. The endpoint required was euthanasia or laparoscopy to identify adhesion formation. A meta-analysis was performed using a random effects model, with the effect size calculated as an odds ratio (OR) with 95% confidence intervals (CI). Statistical significance was set at P<.05. RESULTS Out of 354 peer reviewed publications that met the search criteria, a total of 9 relevant studies were identified and investigated the use of sodium carboxymethylcellulose (CMC) solutions, sodium hyaluronate/carboxymethylcellulose (HA/CMC) membranes, hyaluronate (HA), and fucoidan solutions. The odds of adhesions in horses treated with an adhesion barrier were significantly lower than untreated controls (OR=0.102; 95% CI [0.041, 0.254]; P<.001). When analyzed as subsets for each type of barrier, horses treated with HA/CMC membranes and CMC solutions had significant OR for fewer adhesions (OR=0.061; 95% CI [0.013, 0.292]; OR=0.119; 95% CI [0.034, 0.415], respectively; P<.001). CONCLUSION The meta-analysis demonstrated adhesion barriers provide a positive effect on the odds of adhesion formation. These results are tempered by the limitations of the study, including the small sample size and a bias towards publication of studies with only positive findings.