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

Abstract

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

MRI Study of Jellyfish Collagen, Hyaluronic Acid, and Cadaveric Dermis for Injection Laryngoplasty

“…Three compounds have gained prominence: calcium hydroxyl-apatite and its carboxymethyl cellulose carrier (Radiesse ® ), cross-linked hyaluronic acid (Restylane ® ), and human cadaveric micronized acellular dermis (Cymetra ® ). As novel materials such as silk 5 and tissue-mimetic nano-fibrillar hybrids 6 are being developed, a more personalized approach to IL may become possible.…”

Fibrin Gel Suspended Autologous Chondrocytes as Cell‐based Material for long‐term Injection Laryngoplasty

“…For this reason, hydroxyapatite has been introduced for vocal cord injection and is increasingly used 25 . Although its better durability and volume stability, often for a few years, is favorable for persistent vocal fold paralysis with a glottic gap, several adverse reports of foreign body reactions and granuloma formation, 26,27 and even implant migration together with dislocation of the material 28 and an unfavorable biomechanical aspect attributable to the stiffness of the material regarding phonation 29 have appeared in the literature. One material that was thought to combine favorable biomaterial and biomechanical characteristics and endurance properties was autologous fat.…”

“…A new material recently invented with the intention of use in vocal fold augmentation is a silk‐protein microparticle‐based filler. This novel material has provided favorable results in in vitro studies and in vivo in a canine model 28,33 . Its long‐term volume and form stability, plus its biomechanical properties in vivo , have yet to be tested, with inflammation representing a possible problem 28 .…”

“…This novel material has provided favorable results in in vitro studies and in vivo in a canine model 28,33 . Its long‐term volume and form stability, plus its biomechanical properties in vivo , have yet to be tested, with inflammation representing a possible problem 28 . Minced cartilage has also been introduced as an option for long‐term augmentation, but the authors have also found foreign body reaction and degradability on its use 34 …”

Progress in Vocal Fold Regenerative Biomaterials: An Immunological Perspective

“…Biomaterials can travel significant distances from the original implantation site, such as vocal fold biomaterials migrating to cervical or retropharyngeal lymph nodes. [86,87] Migration hinders biomaterial long-term efficacy and performance and can lead to significant health complications or failure of the implant (Figure 3).…”