Three-Year Follow-Up and Experience With Delayed Reinjection Using Silk-Hyaluronic Acid for Vocal Fold Augmentation

Silk-hyaluronic acid (silk-HA), a true vocal fold (TVF) augmentation material used in humans since July 2020 for correcting glottic insufficiency, has demonstrated long-term, durable results over 12 months after injection. Collagen ingrowth and fibrosis replacing the silk-HA scaffold over approximately 18 months are expected to provide the durable effect. Outcomes and observations from patients presenting with follow-up periods greater than 3 years as well as patients who needed additional silk augmentation but were delayed more than 18 months in getting their "touch up" procedure are presented.

Retrospective chart review from patients who underwent silk-HA TVF augmentation from 2020 to 2025. Patients were divided into two groups. The "long-term follow-up" group includes patients who presented for follow-up at least 3 years after a satisfactory silk-HA augmentation outcome. The "reinjection" group is comprised of patients who were reinjected with silk-HA at least 18 months after their first injection. Voice Handicap Index-10 (VHI) and laryngovideostroboscopic (LVS) findings were analyzed. Descriptive analysis was performed.

Sixteen patients had follow-up longer than 3 years, six patients had complete follow-up records, two of them completed a 4-year follow-up; 100% had maintained satisfactory augmentation effect after LVS video reviews. Nine patients met the inclusion criteria for reinjection-a fibrotic area that made additional augmentation more challenging but not impossible was appreciated in 4 of them.

Silk-HA demonstrates a lasting effect for at least 3 years in a cohort who underwent some of the earliest silk-HA augmentations. A subset of the patients who required further augmentation with silk-HA in a delayed fashion (18 months or more after initial augmentation) demonstrated the expected fibrosis where the material was originally injected, as evidenced through more challenging transnasal endoscopic needle placement and material delivery.