Experimental Study On Acellular Dermal Matrix And Autologous Fat Injected Into Rabbit Vocal Cords

Patients with glottic insufficiency secondary to laryngeal palsy, scarring and sulcus vocalis may present with varying degrees of dysphonia, dysphagia, or aspiration risk. Injection laryngoplasty has been investigated as a means of vocal fold medialization as early as 1911.Advantages of IL include technical simplicity, minor trauma, and performed under local anesthesia.Vocal fold augmentation by injection laryngoplasty is a straightforward and effective treatment modality for glottal insufficiency,but foreign body reactions,fibrosis,granulomas formation caused by implants and the possibility of extrusion turned the procedure limited in clinical practice.More recently,it has become a popular alternative treatment due to the development of new biomaterials,which is histologically similar to the lamina propria deep layer, and gradually replace non biomaterials.At present, the vocal fold augmentation material variety, is still difficult to clear the best. Objective The purpose of the experimental study on an animal model was to determine the histologic changes and the absorption rate of autologous fat and ADM in paralyzed rabbit left vocal fold. Methods 16 New Zealand white rabbits of both sexes were divided into two study groups of 8 rabbits each,whose larynges were grafted by vocal fold lipoinjection and ADM injection.The larynges were collected 2,4,8 and 12 weeks after injection,and the tissues were stained for histological analysis and volume calculation. Results The remaining volume of autologous fat and ADM reduced gradually, there were no statistically significant differences between the 2 groups.In 2 weeks, fat cells survival was mass distribution, as its necrosis and absorption, Intraimplant resulted in a plurality of cavitation,encapsulated by fibrous connective, mixed with a little survival fat cells; in 12 weeks,obvious capsule formation surrounded lipoma composed of fiber connective tissue.In the ADM group, 2 weeks after injection, Intraimplant fibroblast activity and neovascularization was noted,later fibroblast infiltration increased gradually. In 12 weeks, the implantation maintaun the basic outline and have compact organizational structure, but not forming obvious boundaries with the surrounding tissue. Conclusion Comparing degree of absorption, there were no statistically significant differences between autologous fat and ADM in the study,but histological outcome of ADM is closer to the original organization.In future,ADM optimization or combination with other materials, will have a larger development and clinical application value.