In otology, a wide variety of devices are used that have significant noise output, both operated ear and the patient. We aimed to determine hearing damages due to drill-generated acoustic trauma in ear surgery. We want to find how degree drill-generated acoustic trauma is responsible from sensorineural hearing loss in ear surgery.

We designed a retrospective study about 100 patients who underwent radical or modiphied radical mastoidectomy and tympanoplasty. The audiometric testing was done both pre and postoperatively to detect any significant hearing loss in the immediate postoperative period. The data were analyzed using the Wilcoxon sign and Mann-Whitney U tests. This study proposes that hearing loss is caused by drill noise conducted to the operated ear by vibrations of temporal bone.

A sensorineural hearing loss soon after mastoid surgery is seen due to the noise generated by the drill. Mean pure-tone thresholds obtained was significantly more in mastoidectomy applied patients when compared to tympanoplasty . Mean bone conduction (BC) hearing levels impaired 6,6 dB in 1 kHz, 5.5 dB in 0.5 kHz, 5 dB in 4.kHz and 3.1 dB in 2 kHz in mastoidectomy groups but improved 5.5 dB in 0.5 kHz, 2.2 dB in 1 kHz, 2.7 dB in 2 kHz in tympanoplasty groups. Statistically significant differences were observed at the 0.5-1 and 4 kHz frequencies pre and postoperative in the hearing thresholds of BC changing in mastoidectomy group, however, the averages of ranks of all pre and postoperative measurement of hearing levels show differences between mastoidectomy and tympanoplasty groups was significant in statistically at independent groups (p < 0.05).

We conclude that drill-generated noise during mastoid surgery has been incriminated as a cause of sensorineural hearing loss. Drilling during mastoid surgery may result in temporary or permanent noise-induced hearing loss. Possible noise disturbance to the inner ear can only be avoided by minimizing the duration of harmful noise exposure and carefull using burr to near the cochlear structures.

Paksoy M, Sanli A, Hardal U, Kibar S, Altin G, Erdogan BA, Bekmez ZE. How Drill-Generated Acoustic Trauma effects Hearing Functions in an Ear Surgery? Int J Head and Neck Surg 2012;3(3):127-132.