Correlation Between the Effects of CO Laser and Histopathological Analysis in Vocal Cord Lesions: An Observational Study.

Lasers are based on the principle of light amplification by empowering atoms to store and emit light in a coherent form. Through their effect on tissues, lasers reduce hemorrhage allowing the surgeon to work in a clear field with precise removal of the tissues. Irradiation of the soft tissues by lasers produces thermal effects on the surrounding healthy tissues which can make histopathological examination difficult. Hence this study was done to find a correlation between adjustable parameters of CO laser and the extent of collateral thermal damage in the excised vocal cord lesions on histopathological examination and diagnosis. In this study, we enrolled 80 patients who were divided into 4 groups with different combinations of laser power and mode, used during transoral laser micro laryngeal surgery for the excision of vocal cord lesions and subsequent histopathological analysis to objectively measure the extent of thermal damage zone and subjectively assess histo-morphological effects of thermal damage in terms of grade of carbonization. The extent of the thermal damage zone is directly related to the power of the laser, but the mode of the laser had no relation with the thermal damage zone in our study. On subjective histo-morphological examination of excised lesions showed that both power and mode of laser have significant effects on tissue morphology. Continuous mode causes a significantly higher grade of carbonization as compared to the superpulsed mode of the laser. However, in our study it was seen that charring in no way affected the diagnosis in any of the biopsies examined whatever the power or mode of the laser used. The depth and width of the tissue thermal damage zone are mainly dependent upon the laser parameters (power and mode). Although considering the limitations of this study carried out in terms of sample size, it would be pertinent to mention here that further studies with larger cohorts need to be done to authenticate these results.