Tsukasa Ito1, Toshinori Kubota2, Akira Takagi3, Tomoo Watanabe2, Kazunori Futai2, Takatoshi Furukawa2, Seiji Kakehata2. 1. Department of Otolaryngology, Head and Neck Surgery, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata-shi, Yamagata 990-9585, Japan. Electronic address: tuito@med.id.yamagata-u.ac.jp. 2. Department of Otolaryngology, Head and Neck Surgery, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata-shi, Yamagata 990-9585, Japan. 3. Division of Dentistry and Oral Surgery, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata-shi, Yamagata 990-9585, Japan.
Abstract
OBJECTIVE: To determine whether heat generated by endoscope light sources during ear surgery is safe. METHODS: Transcanal endoscopic ear surgery (TEES) was simulated using 2.7-mm or 4-mm endoscopes coupled to xenon or LED light sources and a 3D model of human temporal bone. The endoscope tip was fixed at the center of tympanic annulus. Light sources were tested at clinical (30% for xenon and 40% for LED) and 100% settings. Temperatures were measured using thermocouples attached to the endoscope tip and three points within the middle ear cavity: promontory, horizontal portion of the facial nerve and lateral semicircular canal. RESULTS: Maximum temperatures measured within the middle ear cavity were below 31°C at clinical settings, while the temperatures rose to 44.1°C using a 4-mm endoscope with a xenon light source set at 100%. Temperatures measured at the tip were all safe at clinical settings, but rose dramatically to 110.1°C for the 4-mm endoscope with xenon at 100%. CONCLUSION: Endoscopes can be safely used within the middle ear at clinical settings. However, operators should not exceed clinical settings, particularly with 4-mm endoscopes with a xenon light source, to ensure temperatures generated within the middle ear cavity are safe.
OBJECTIVE: To determine whether heat generated by endoscope light sources during ear surgery is safe. METHODS: Transcanal endoscopic ear surgery (TEES) was simulated using 2.7-mm or 4-mm endoscopes coupled to xenon or LED light sources and a 3D model of human temporal bone. The endoscope tip was fixed at the center of tympanic annulus. Light sources were tested at clinical (30% for xenon and 40% for LED) and 100% settings. Temperatures were measured using thermocouples attached to the endoscope tip and three points within the middle ear cavity: promontory, horizontal portion of the facial nerve and lateral semicircular canal. RESULTS: Maximum temperatures measured within the middle ear cavity were below 31°C at clinical settings, while the temperatures rose to 44.1°C using a 4-mm endoscope with a xenon light source set at 100%. Temperatures measured at the tip were all safe at clinical settings, but rose dramatically to 110.1°C for the 4-mm endoscope with xenon at 100%. CONCLUSION: Endoscopes can be safely used within the middle ear at clinical settings. However, operators should not exceed clinical settings, particularly with 4-mm endoscopes with a xenon light source, to ensure temperatures generated within the middle ear cavity are safe.