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

Area of Science:

• Otolaryngology
• Regenerative Medicine
• Vocal Fold Physiology

Background:

• Silk-hyaluronic acid (silk-HA) is an established vocal fold (VF) augmentation material for glottic insufficiency.
• It has shown durable results exceeding 12 months post-injection.
• Tissue remodeling via collagen ingrowth and fibrosis is anticipated to sustain the augmentation effect.

Purpose of the Study:

• To evaluate the long-term outcomes of silk-HA VF augmentation.
• To assess patients with follow-up exceeding 3 years.
• To examine outcomes in patients requiring delayed silk-HA reinjection (over 18 months post-initial augmentation).

Main Methods:

• Retrospective chart review of patients undergoing silk-HA VF augmentation (2020-2025).
• Two groups: "long-term follow-up" (≥3 years post-augmentation) and "reinjection" (≥18 months between injections).
• Analysis of Voice Handicap Index-10 (VHI) and laryngovideostroboscopic (LVS) findings.

Main Results:

• 100% of patients with >3 years follow-up maintained satisfactory augmentation.
• Two patients completed 4-year follow-up.
• In the reinjection group, 4 out of 9 patients showed challenging fibrosis at the original injection site, though reinjection was still feasible.

Conclusions:

• Silk-HA demonstrates sustained efficacy for at least 3 years in vocal fold augmentation.
• Delayed silk-HA reinjection (>18 months) can encounter fibrosis at the injection site.
• Fibrosis, while noted, does not preclude successful additional augmentation with silk-HA.