Noninvasive Measurement of Ablation Crater Size and Thermal Injury after CO 2 Laser in the Vocal Cord with Optical Coherence Tomography

OBJECTIVES: To characterize tissue destruction after CO₂ laser-ablation of the vocal cords with the use of optical coherence tomography (OCT).

STUDY DESIGN AND SETTING: OCT was used to image fresh porcine vocal cords after laser ablation. OCT and histology estimates of the ablation crater dimensions and the depth of thermal injury were obtained.

RESULTS: The vocal cord substructures up to 2.29 mm in depth at 10 μm resolution, and the thermal disruption after laser ablation were identified by OCT. OCT and histology estimates of the lesion dimensions showed no significant differences. Crater depth is directly proportional to laser power, whereas crater width and the zone of thermal injury appear to be unrelated to laser power.

CONCLUSIONS: OCT may be used to accurately characterize the native states and the laser-induced thermal injury of laryngeal mucosa, within the inherent limitation in its depth of penetration. OCT may be a useful diagnostic and monitoring tool in an otolaryngology practice.