How Drill-Generated Acoustic Trauma effects Hearing Functions in an Ear Surgery?

Abstract

Objective: 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. Materials and methods: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.Results: 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). Conclusion: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.

Does Drilling Induce Hearing Loss after Modified Radical Mastoidectomy? A Retrospective Study

“…1 and 6.6 dB). 9 This is similar to our study where there is a decline in 3 dB compared to preoperative status in lower frequencies (Figure 1).…”

“…5,6 The intensity of noise generated depends on various parameters including rotation speed, type of burr, burr size, and site of drilling (a solid area or aerated area).9 Mastoid drilling with larger size (6 mm cutting) burr generates an intensity of 88 to 108 dB, whereas there is further noise reduction with decreased burr size and the maximum reduction is seen with the small 2 mm burr (up to 16 dB). 9 The sound pressure level produced by the cutting burr is more than the levels of the diamond burr, so, in vital structures diamond burr is advised. 10,11 High-speed drill produces a low noise level causing less damage to hair cells of the cochlea and is safer compared to the low-speed drill that generates the highest intensity sound.…”

“…10,11 High-speed drill produces a low noise level causing less damage to hair cells of the cochlea and is safer compared to the low-speed drill that generates the highest intensity sound. 9 The risk of sensorineural hearing loss is increased when drilling the ossicular chain directly or after an inadvertent touch.12 The intensity is low in the aerated mastoid air cells and higher in solid bones and ossicles. Drill-induced noisy sound has been suspected as a cause of about 5 dB SNHL in all frequencies in mastoidectomy (range 3.…”

Effect of drill-induced noise on hearing in non-operated ear

“…They reported that bone conduction can impaired with drill noise most at frequencies but, they showed PTA changes can be permanent. [ 16 ] Kylén and Arlinger had described that the noise trauma can account some patient in high-tone frequency after tympanoplasty. [ 17 ] As the values, different frequencies of DPOAEs and TEOAEs were significantly different preoperatively and postoperative (1 and 7 days).…”

A study of occurrence of postoperative sensorineural hearing loss after middle ear surgeries

“…19 Paksoy et al, in their study state that drill induced sensorineural hearing loss is one of the causes of hearing loss. 20 Alharbi et al, in their study state that one should avoid touching ossicular chain during ear surgery as a high focused acoustic energy is transmitted to inner ear causing damage in structure and deterioration of function. Spontaneous recovery could occur after acoustic trauma but may be incomplete with permanent scar formation in outer haircells.…”