Effect of application of fibrin glue on vocal fold healing after surgical manipulation in rabbits

INTRODUCTION

A challenge in phonosurgery is achieving good vocal quality with minimal vocal fold fibrosis. Fibrin glue can be applied to minimize fibrosis; however, its use in the larynx is based primarily on clinical experience, particularly in extensive lesions.

OBJECTIVE

The objective of this study was to evaluate the effect of application of fibrin glue on collagen concentration at the late phase of the healing process after detaching a pedicled flap of the vocal fold cover in rabbits.

METHODS

In this prospective animal study, twelve adult male rabbits underwent laryngeal microsurgery, in which an incision was made along the entire length of both vocal folds, followed by extensive mucosal detachment and section of the incision ends. Fibrin glue was applied in the left vocal fold, and the mucosa was repositioned. In the right vocal fold, the mucosa was repositioned without treatment with fibrin glue. After 3-months, the rabbits were euthanized. Histological analyses were performed, and the data collected were subjected to statistical analysis.

RESULTS

Vocal folds treated with fibrin glue presented higher collagen concentration in Masson trichrome staining and significantly higher (p < 0.05) collagen concentration in picrosirius red staining compared to control vocal folds.

CONCLUSION

Treatment with fibrin glue led to greater vocal fold fibrogenesis in the present study. Nonetheless, further studies are necessary to determine the prophylactic effect of sealants in laryngeal surgeries that require extensive detachment of the vocal fold cover.

The Effect of Fibroblast Growth Factors in Grafted Fascia into the Vocal Fold of Rabbits

Introduction  The human larynx is a very important organ for communication. Many conditions lead to scarring of the vocal folds, decreasing voice quality. Objective  We aimed to determine whether fibroblast growth factors (FGFs) may influence tissue integration of grafted fascia into the vocal folds of an animal model. Methods  This is an experimental animal study with 12 adult rabbits that were submitted to a grafting fragment obtained from superficial cervical fascia into the vocal fold lamina propria, bilaterally. The right vocal fold was injected with FGFs. The animals were sacrificed after 1 month or 12 months, depending on the group they were assigned to, and a histological analysis of their vocal folds was performed. We analyzed the histological changes (such as the presence of fibrosis and neovascularization) induced by the acute or chronic inflammatory reactions. Results  The FGFs induced acute inflammatory changes in all animals after 1 month of the initial experiment. The presence of FGFs triggered more fibrosis than the expected due to the surgical procedure itself when compared with the control side of all animals after 12 months of the initial experiment. Conclusions  Fibroblast growth factors alone do not represent a good therapeutic option in phonosurgery, since we observed higher levels of fibrosis in the vocal fold lamina propria. Further studies combining more substances may be necessary to elucidate the best option to be used in this kind of surgery.