Temperature rises in the round window caused by various light sources during insertion of rigid endoscopes: an experimental animal study

ObjectivesThe instruments used in endoscopic surgery include rigid endoscopes of different diameters and angles, sources of light and monitors. In this study, we explored temperature rises in the round window caused by insertion of rigid endoscopes of different diameters into the middle ear; the endoscopes were fitted with different light sources. DesignAn experimental animal study. SettingWe subjected seven guinea pigs to simulate otological surgery at room temperature. We monitored body temperatures, along with temperature rises caused by the use of 0 degrees rigid endoscopes of diameters 3 or 4mm, fitted with light sources including a halogen light, a light-emitting diode (LED) and a xenon light. Data were collected every second from a sensor placed in the round window. ParticipantsAn experimental study on 7 guinea pigs. Main Outcome MeasuresRise of the temperature on round window. ResultsRigid endoscopes caused the temperature of the tympanum to rise when xenon and halogen light sources were used, regardless of endoscope diameter. However, the temperature rise was less when a LED light source was employed. ConclusionThe endoscopic instruments used in middle ear surgery caused the temperature of the round window to rise. The rise varied with endoscope diameter and the type of light source used.