Drill-induced hearing loss in contrlateral healthy ear after mastoid surgery

Purpose: This study was undertaken to measure the degree of drill-induced hearing loss after the mastoid surgery of the patients that whose contrlateral ear was healthy. Materials and Methods: Twenty-two patients undergoing mastoidectomy procedures were tested preoperative^ and postoperatively using otoacoustic emissions and tymponometer. Acoustic stapedial reflexes (ASR) and transient otoacoustic emissions (TEOAE), spontaneous otoacoustic emissions (SOAE), distortion product otoacoustic emissions (DPOAE), DPOAE Input/Output (I/O) parameters were measured in nonopereted healthy ears in preoperative periods and postoperative six days. Results: Acoustic stapedial reflex was decreased against the drill inuced noise for the protection of inner ear in postoperative time. The recovery in stapedial reflex was occured after 48-72 hours later in all patients. Otoacoustic emissions amplitude measurements were also decreased by the drill induced noise. Temporary threshold increasing were seen in DPOAE I/O. Increasing in emissions amplitudes and decreasing in thresholds were occured in postoperative 48-72 hours. Conclusions: In mastoid surgey drill-induced noise can affect the nonoperated contrlateral healthy ear. Temporary decreasing in acoustic stapedial reflex and emissions amplitudes, increasing in thresholds may occur. These events are not permanent changes. Increasing in acoustic stapedial reflexes and emissions amplitudes, decreasing in thresholds can be seen ratherly early in postoperative time. Key-words: Noise, temporary threshold shifts, otoacoustic emissions, acoustic stapedial reflexes