Effect of drill-induced noise on hearing of nonoperated ear after mastoidectomy

Abstract

Background Chronic suppurative otitis media is an inflammation of middle ear of more than 2 weeks with treatment without improvement. Aim The aim was to evaluate the effect of drill-generated noise after mastoidectomy on hearing status of the nonoperated ear. Patients and methods This is a prospective study of 40 patients with unilateral chronic suppurative otitis media attending ENT Departments of Al-Zahraa University Hospital, Faculty of Medicine (Girls), Al-Azhar University, and El-Maadi Armed Forces Medical Complex during the period from August 2018 till September 2019. Patients were divided into two equal groups: group A included 20 patients who underwent mastoidectomy operations with the usage of mastoid drilling and group B underwent myringoplasty without the usage of drilling. Pure tone audiometry (PTA) and otoacoustic emissions (OAEs) were done for nonoperated ear of all patients preoperatively and at days 1, 2, and 7 postoperatively. Results Result showed that postoperative nonoperated ear hearing was affected in group A. This effect is not significant enough to cause hearing loss as detected by PTA but can be detected by OAE in which their amplitude deteriorated at first day postoperatively and improved after that back to the normal preoperative values within 1 week. However, hearing in nonoperated ear of group B was not affected by observation of PTA or OAE. Conclusion Drill-induced noise during mastoidectomy affects hearing of contralateral nonoperated ear temporarily through some outer hair cells (OHC) damage.