Inner Ear Effects of Canal Wall Down Mastoidectomy: A Prospective Study

Abstract

Objective: Evaluate the inner ear effects of canal wall down (CWD) mastoidectomy in the treatment of chronic otitis media (COM) in regard to bone conduction hearing and reported tinnitus and dizziness related disability. Method: Prospective study of 86 consecutive patients treated by CWD mastoidectomy for COM with or without cholesteatoma. Patients underwent preoperative audiogram and completion of 2 surveys: Dizziness Handicap Inventory (DHI) and Tinnitus Handicap Inventory (THI), which were repeated 4 to 6 months postoperatively. Results: No significant change in bone-conduction hearing scores occurred postoperatively. DHI and THI scores improved in the vast majority of patients. Thirteen patients, 13 out of 34 (38%), had DHI improvement greater than 18 points, indicating a significant patient-perceived improvement in dizziness-related disability. Sixteen patients, 16 out of 43 (37%), had THI improvement greater than 20 points, indicating a significant patient-perceived improvement in tinnitus-related disability. Three patients developed new-onset postoperative dizziness, and 5 patients developed new-onset postoperative tinnitus. The odds ratio for improving DHI and THI scores relative to or worsening scores is 6.6 in DHI (95% CI: 1.8 to 25.0) and 4.2 in THI (95% CI: 1.45 to 12.2). Conclusion: Canal wall down mastoidectomy did not result in new-onset sensorineural hearing loss. In addition, using the Dizziness Handicap Inventory and Tinnitus Handicap Inventory measures, patient-perceived disability from dizziness and tinnitus was shown to decrease after mastoid surgery.