Effect of drill noise on contralateral hearing after mastoidectomy in cases of unilateral Chronic Otitis Media

Abstract

Introduction: The mainstay of treatment of Chronic Otitis Media (COM) is Tympanoplasty with or without Mastoidectomy. This study was conducted in patients undergoing Tympanoplasty with Mastoidectomy to assess Sensorineural Hearing Loss (if any) due to drill noise on the contralateral ear. Materials and Methods: A total of 25 patients with unilateral COM scheduled to undergo Mastoidectomy and Tympanoplasty who fulfilled inclusion criteria were recruited in the study, and a prospective, observational pilot study was carried out. Pure Tone Audiometry (PTA) and Transient Evoked Otoacoustic Emissions (TEOAE) were recorded preoperatively and postoperatively to assess hearing loss if any on the contralateral side. Results: There was no change in bone-conduction thresholds in the contralateral ear by PTA postoperatively. However, there was a significant worsening in the values of signal-to-noise ratio of TEOAE at all the frequencies in the postoperative period. The mean TEOAE recordings were, however, above 3 dB SPL. Conclusion: There are statistically significant effects of drill noise on the inner ear function on the contralateral ear as detected by TEOAE; however, the effects are not detectable on PTA. Larger studies with a longer follow-up period will be required to determine if the early postoperative effects on TEOAE are reversible or persist.

Keywords

• Chronic Otitis Media
• effects of drilling
• Mastoidectomy
• Noise Induced Hearing Loss
• Pure Tone Audiometry
• Transient Evoked Otoacoustic Emissions