New Imaging Technique Could Transform Precision of Vocal Fold Injection Procedures

AAO-HNSF

Researchers at Stanford University, in collaboration with scientists at the German Cancer Institute, have shown for the first time that shortwave infrared (SWIR) imaging can be used to visualize injectable filler materials during injection laryngoplasty, a common procedure used to treat vocal fold paralysis and other forms of glottic insufficiency. The findings, published in Otolaryngology–Head and Neck Surgery, on this novel visualization technique could pave the way for precision-guided laryngeal surgery.

Tulio A. Valdez, MD, MSc“Shortwave infrared imaging can be a game-changer for injection laryngoplasty because it enables real-time, high-contrast visualization of injected materials beneath the mucosa, allowing precise localization, improved accuracy of vocal fold augmentation, and immediate confirmation of treatment adequacy,” said Tulio A. Valdez, MD, MSc, corresponding author and Professor of Otolaryngology - Head & Neck Surgery at Stanford Medicine.
 

Roy Kiwan Park, MDLead author Roy Kiwan Park, MD, and the research team used a custom SWIR imaging system operating in the 1000–2000 nm wavelength. They found that imaging at 1550 nm produced significantly greater contrast between vocal fold tissue and surrounding respiratory mucosa compared to visible-light imaging driven by differences in water content between the two tissue types.

The combination of reflection and fluorescence SWIR imaging offers a multimodal approach that could help surgeons confirm correct filler placement in real time, identify misplaced superficial injections, and potentially monitor filler resorption over time. 

While the study was conducted in a laboratory setting using ex vivo tissues, the authors note that the optical setups could be integrated into endoscopes or operating microscopes for clinical use. The cost of SWIR camera technology has decreased substantially in recent years, making broader clinical adoption increasingly feasible.

Beyond injection laryngoplasty, the researchers suggest SWIR imaging could have future applications in identifying vocal fold pathologies such as cysts and polyps, differentiating layers of the vocal fold based on water and collagen content, and detecting areas of laryngeal inflammation.

Reference

Park, R.K., Lee, M.C., Härtl, S., Arús, B.A., Nuyen, B., Sung, C.-K., Baik, F.M., Bruns, O.T., and Valdez, T.A. (2026). Multimodal Shortwave Infrared Imaging for Visualization of Injection Laryngoplasty. Otolaryngol Head Neck Surg, 174: 185-194. https://doi.org/10.1002/ohn.70050