Copyright © 2018 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited. Occupational Noise Exposure and Risk for Noise-Induced Hearing Loss Due to Temporal Bone Drilling  Yona Vaisbuch,  Jennifer C. Alyono,  Cherian Kandathil, yStanley H. Wu,  Matthew B. Fitzgerald, and  Robert K. Jackler  Department of Otolaryngology—Head and Neck Surgery, Stanford School of Medicine; and yDepartment of Environmental Health and Safety, Stanford University, Stanford, California Background: Noise-induced hearing loss is one of the most common occupational hazards in the United States. Several studies have described noise-induced hearing loss in patients following mastoidectomy. Although otolaryngologists care for patients with noise-induced hearing loss, few studies in the English literature have examined surgeons’ occupational risk. Methods: Noise dosimeters and sound level meters with octave band analyzers were used to assess noise exposure during drilling of temporal bones intraoperatively and in a lab setting. Frequency specific sound intensities were recorded. Sound produced using burrs of varying size and type were compared. Differences while drilling varying anatomic structures were assessed using drills from two manufacturers. Pure tone audiometry was performed on 7 to 10 otolaryngology residents before and after a temporal bone practicum to assess for threshold shifts. Results: Noise exposure during otologic drilling can exceed over 100 dB for short periods of time, and is especially loud using large diameter burrs > 4 mm, with cutting as compared with diamond burrs, and while drilling denser bone such as the cortex. Intensity peaks were found at 2.5, 5, and 6.3 kHz. Drilling on the tegmen and sigmoid sinus revealed peaks at 10 and 12.5 kHz. No temporary threshold shifts were found at 3 to 6 kHz, but were found at 8 to 16 kHz, though this did not reach statistical significance. Conclusion: This article examines noise exposure and threshold shifts during temporal bone drilling. We were unable to find previous descriptions in the literature of measurements done while multiple people drilling simulta- neously, during tranlabyrinthine surgery and a specific frequency characterization of the change in peach that appears while drilling on the tegmen. Hearing protection should be considered, which would still allow the surgeon to appreciate pitch changes associated with drilling on sensitive structures and communication with surgical team members. As professionals who specialize in promoting the restoration and preservation of hearing for others, otologic surgeons should not neglect hearing protection for them- selves. Key Words: Burr—Drill—ENT—Neurotologist— Noise-induced hearing loss—Occupational noise exposure— Otologist —Surgeons —Temporal bone lab—Threshold shifts—Tinnitus. Otol Neurotol 39:693–699, 2018. Noise-induced hearing loss (NIHL) is a gradually progressive, sensorineural hearing deficit, typically occurring at higher frequencies (3 – 6 kHz) due to chronic exposure to excessive sound (1). NIHL is one of the most common forms of hearing loss in the United States, present in nearly one in four adults (2). Recognizing the potential for excessive noise exposure in the workplace, the Occupational Health and Safety Administration (OSHA) regulates both maximum sound levels and allowable time-weighted average (TWA) exposures (3). Current guidelines mandate that employ- ers offer a hearing conservation program to employees should they be exposed to sound levels greater than 85 dBA, which is known as the ‘‘action level.’’ Ninety dBA averaged over an 8-hour period is the maximum ‘‘per- missible exposure limit.’’ Furthermore, for each addi- tional increase in 5 dBA of TWA noise exposure, employees must halve their exposure time. The National Institute for Occupational Safety and Health is the research body that makes recommendations to OSHA (4). Their recommended exposure limit is stricter, at 85 dBA averaged over an 8-hour period. They also recom- mended halving exposure time for each additional increase in 3 dBA of TWA noise exposure (see Table 1). While the role of noise exposure in the workplace has been extensively studied for many professions, relatively little is known about the potential for noise exposure in surgical professions. Shapiro and Berland in 1972 reported one of the first studies of occupational noise exposure in the operating room (5). Measuring sound Address correspondence and reprint requests to Yona Vaisbuch, M.D., Stanford University, 450 Serra Mall, Stanford, CA 94305; E-mail: yona@stanford.edu The authors disclose no conflicts of interest. DOI: 10.1097/MAO.0000000000001851 693 Otology & Neurotology 39:693–699 ß 2018, Otology & Neurotology, Inc.