Gelatin-Based Hemostatic Agents: Histopathologic Differences

Purpose: To delineate the histopathologic appearance of gelatin-based hemostatic agents, Surgiflo, Gelfoam, and Floseal, which are used by ophthalmic plastic surgeons, and which may incidentally be found as foreign materials in histopathologic tissue samples. Methods: Histopathologic analysis was performed with hematoxylin-eosin, periodic acid-Schiff, Masson trichrome, and elastin staining on tissue samples in which gelatin-based agents were found. To better characterize these materials, similar analyses were performed on in vitro samples of commonly used gelatin-based hemostatic agents. Results: Surgiflo and Gelfoam are composed of small stellate pieces of gelatin with a smooth, homogeneous quality. In tissues, they are faintly positive with periodic acid-Schiff staining, amphophilic with Masson trichrome staining, and ink-black with elastin staining. Floseal has a distinctly different morphology of large rectangular sheets, yet almost identical in vitro staining properties. Discussion: While the morphology of the gelatin-based hemostatic agents is consistent under various conditions, the staining properties of these materials differ based on whether they have been in contact with human tissue. Conclusions: Gelatin-derived hemostatic agents are best identified based on their morphologic characteristics. Elastin staining highlights these materials prominently within tissue samples and may be helpful in distinguishing them from other foreign materials.