A novel silk‐based vocal fold augmentation material: 6‐month evaluation in a canine model

• Published in: The Laryngoscope 2019-08, Vol.129 (8), p.1856-1862
• Main Authors: Gulka, Christopher P., Brown, Joseph E., Giordano, Jodie E.M., Hickey, Jennifer E., Montero, Maria P., Hoang, Anh, Carroll, Thomas L.
• Format: Article
• Language: English
• Subjects: canine histology; endoscope‐guided delivery; Hyaluronic acid; injection augmentation; Silk; vocal fold injectable
• ISSN: 0023-852X; 1531-4995
• DOI: 10.1002/lary.27618

Objectives Ideal long‐term vocal fold augmentation materials should be biocompatible, easily administered, allow tissue integration for long‐term effect, and remain at the site of injection. A novel silk protein particle suspended in hyaluronic acid (Silk‐HA) has been developed specifically for vocal fold augmentation to address this unmet need. This article presents the 6‐month, preclinical findings of a canine vocal fold injection trial for Silk‐HA. Methods Twelve beagle dogs were injected transorally in the lateral/deep aspect of their right thyroarytenoid muscles with 0.3 cc of Silk‐HA or calcium hydroxylapatite in carboxymethyl cellulose (CaHA‐CMC). The Silk‐HA particle injectable was delivered via a custom catheter, whereas CaHA‐CMC was delivered through a commercially available malleable needle. The six dogs from each material group were sacrificed 6 months from the injection date for the evaluation of implant longevity, immune response, and material migration. Results Silk‐HA provides immediate medialization of the right vocal fold, lasting for a minimum of 6 months in a canine model. Silk‐HA and CaHA‐CMC both demonstrate similar inflammatory responses. The Silk‐HA was shown to remain without migration at the site of injection in all six canine subjects, whereas CaHA‐CMC demonstrated migration in four of the six canines. In two canines implanted with CaHA‐CMC, material was discovered to migrate to the retropharyngeal lymph nodes. Conclusion In a canine subject model, the Silk‐HA material compares favorably in terms of longevity and immune response to CaHA‐CMC. The lack of migration of the Silk‐HA material demonstrates a promising potential for vocal fold injection in the clinic. Level of Evidence NA Laryngoscope, 129:1856–1862, 2019