Bengal Journal of Otolaryngology and Head Neck Surgery (Dec 2014)
Evaluation of the Effect of Drilling on Hearing in Ear Surgery
Abstract
Aim To evaluate and assess the effect of micro drilling on sensorineural hearing loss in mastoid surgery in ipsilateral and/or contralateral ear and to find out the reasons for such a disaster. Methods Forty four patients of unilateral chronic otitis media with squamosal disease with conductive hearing loss requiring mastoid surgery were clinically examined and investigated for deafness in the pre-operative and postoperative period. This retrospective observational study was done from January 2013 to June 2014 at a tertiary care hospital in Kolkata. Pure tone audiometry and OAE were done in the pre-operative and post-operative period. Canal wall mastoidectomy was done in all the patients studied. Results were compared and analyzed to detect association between drilling during mastoid surgery and sensorineural deafness. Results Postoperatively one out of 44 patients developed ipsilateral sensorineural loss. The patient had developed post operative grade IV facial nerve palsy with bone conduction dip at 2000 and 4000 Hz. Conclusion Post operative sensorineural loss following Canal wall down mastoidectomy can occur due to noise and extreme heat generation, vibration of the temporal bone, inadvertent opening up of labyrinth or drilling on the intact ossicular chain etc.
