BACKGROUND: The carbon dioxide (CO(2)) laser in endolaryngeal surgery is a successful tool because of its implementation of the thermally induced hematostatic incision technique. We investigated the problem of thermal damage of surrounding tissue during laser surgery. Until now a potential damage of surrounding healthy mucosa caused by laser surgery through general heating up, hot gases and steam has scarcely been noticed. During prolonged tumor surgery the tender mucosa of the surrounding healthy tissue can be irreversible affected and damaged due to thermal exposure above 45 degrees C.

METHOD: The study was performed on the larynx of a pig cadaver. Temperature probes were placed under the epithelium of the vocal cords on the opposite side of the surgical field to detect any increase in temperature during laser application.

RESULTS: A rise in temperature of up to 32 degrees C was observed in the vocal cord opposite the surgical field after 70 s of laser surgery (output power: 4 W, continuous wave mode) even with continuous aspiration. Protection of the healthy mucosa against thermal radiation caused a rise in temperature of only 3.5 degrees C. An increase in temperature of up to 16.1 degrees C was observed, if intermittent exposures (output power: 4 W, pulse length: 0.5 second, repeat time: 0.1 second) were used.

CONCLUSION: Transferring the presented cadaver studies to in vivo surgery, the laryngologist should take into account heating of collateral healthy tissue up to 69 degrees C (37 degrees C body temperature plus 32 degrees C heating by thermal radiation).