Effects of topically applied biomaterials on paranasal sinus mucosal healing

Background: Recently, nasal packing made of absorbable biomaterial has become increasingly popular. Although absorbable packs are effective for hemostasis, their impact on healing mucosa is unknown. Some have felt that a biocompatible sinus dressing actually may enhance healing, particularly in areas where the mucosa has been stripped. The aim of this study was to determine the effect of topical MeroGel and FloSeal on paranasal sinus mucosal healing in a rabbit model. Methods: Bilateral maxillary sinuses of 12 New Zealand white rabbits were surgically opened and stripped of mucosa. The left maxillary sinus of six rabbits had sterile saline-soaked MeroGel placed in the antrum, and the other six rabbits received FloSeal. The right maxillary sinuses of all 12 animals were stripped and otherwise untreated to serve as stripped controls. The animals were killed at 2 weeks and specimens were examined by light microscopy. Results: MeroGel-treated mucosa showed extensive fibrosis of the basal lamina and lamina propria, complete loss of surface epithelium, and loss of the mucociliary blanket. There was minimal resorption of the MeroGel, and MeroGel fibers were frankly incorporated into the regenerated epithelium, associated with an exuberant lymphocytic infiltrate. FloSeal-treated mucosa showed similar fibrosis of the basal lamina and lamina propria with loss of the mucociliary blanket, although to a lesser degree than the MeroGel- treated group. FloSeal showed similar incorporation into the healed mucosa with lymphocytosis. Controls showed expected submucosal gland reduction, lamina propria fibrosis, and loss of cilia, but the lamina propria fibrosis seen in the MeroGel and FloSeal groups was markedly more prominent. Conclusion: In a rabbit model, MeroGel and FloSeal appear to increase reactionary fibrosis of healing mucosa. These agents also appear to be incompletely resorbed and grossly incorporated into healing tissue. Mucosal healing may be impaired by the application of these agents.