Harmonic scalpel versus flexible CO₂ laser for tongue resection: A histopathological analysis of thermal damage in human cadavers

Objectives: To compare thermal damage caused by Harmonic scalpel and CO₂ laser to cadaveric tongue. Methods: Two fresh human cadaver heads were enrolled for the study. Oral tongue was exposed and incisions were made in the tongue akin to a tongue tumor resection using the harmonic scalpel and flexible C02 laser fiber at various settings recommended for surgery. The margins of resection were sampled, labeled, and sent for pathological analysis to assess depth of thermal damage calculated in millimeters. The pathologist was blinded to the surgical tool used. Control tongue tissue was also sent as a baseline for comparison. Results: Three tongue samples were studied to assess depth of thermal damage by harmonic scalpel. The mean depth of thermal damage was 0.69 mm, (range, 0.51-0.82 mm). Five tongue samples were studied to assess depth of thermal damage by CO₂ laser. The mean depth of thermal damage was 0.3mm, (range, 0.22 to 0.43mm). As expected, control samples showed 0 mm of thermal damage. There was a statistically significant difference between the depth of thermal injury to tongue resection margins by harmonic scalpel as compared to CO₂ laser, (p=0.003). Conclusion: In a cadaveric model, flexible CO₂ laser fiber causes less depth of thermal damage when compared with harmonic scalpel at settings utilized in our study. However, the relevance of this information in terms of wound healing, hemostasis, safety, costeffectiveness, and surgical outcomes needs to be further studied in clinical settings.