Ablation of Teflon Granulomas in the Canine Larynx with the Free-Electron Laser

Abstract

This study develops a canine model for the treatment of laryngeal Teflon granulomas and demonstrates endoscopic ablation using the free-electron laser (FEL) set at a wavelength of 8.5 μm. Laryngeal Teflon granulomas may cause dysphonia and airway obstruction, and they are difficult to remove. The infrared absorption spectrum of Teflon reveals a strong absorption peak centered at 8.5 μm. In this study, 12 dogs had the right vocal cord injected with Teflon paste. Two months later, Teflon granuloma formation was confirmed histologically. Laser incisions into the granulomas were performed at 3 different wavelengths: 7.4 μm (FEL), 8.5 μm (FEL), and 10.6 μm (carbon dioxide laser). Histopathologic analysis was performed at 1 week and 6 weeks after the laser incisions. The FEL at the 8.5-μm wavelength was found to optimally ablate the Teflon granulomas, but the granulomas persisted in the specimens treated with 7.4 μm (FEL) and 10.6 μm (carbon dioxide laser).