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

Abstract 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. (AU)

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.

Evaluation of the Grafted Fascia in the Vocal Fold of Dogs: A Histologic Study.

INTRODUCTION: There is no consensus on the ideal graft for medialization surgery of the vocal folds in the literature. One of the most favorable proposals is the use of autologous fascia, which seems limited by the lack of information regarding the integration of grafted tissue. Our study aims to evaluate the degree of fully engrafted fascia integration in the vocal fold lamina propria of dogs. MATERIALS AND METHODS: Fourteen adult mongrel dogs that underwent intravenous general anesthesia were selected and kept under spontaneous ventilation. A fascia lata fragment of 4 cm2 was obtained from the right leg of each dog. The dogs underwent laryngoscopy; a 3 mm incision was made in the vocal process, next to the vestibular process, and the fascia was grafted into the right vocal fold. The left vocal fold was used as a control. The animals were divided into two groups: group A, evaluated after 2 months of the procedure, and group B, evaluated after 6 months of the procedure. Histologic analysis was made semiquantitatively regarding the presence of inflammatory reaction, fibrosis, and neovascularization. RESULTS: Our final studied group comprised 12 dogs. Microscopic examination of the larynx revealed the absence of any detectable inflammation in the incision site. The lamina propria of the grafted vocal fold showed identifiable compact, thick, and eosinophilic collagen bands. The surrounding tissue showed thin collagen bands with some organization, similar to the contralateral vocal fold. CONCLUSION: The grafted fascia integrates into the vocal fold lamina propria and seems not to cause inflammatory reaction response.