A 32-year-old woman presents with progressive bilateral hearing loss over 2 years. Otoscopy is normal. Weber test shows lateralization to the right ear, and Rinne test shows bone conduction better than air conduction bilaterally. Audiometry confirms bilateral conductive hearing loss with an air-bone gap of 40 dB. High-resolution CT temporal bones shows bilateral stapes footplate fixation with no ossicular discontinuity. What is the most appropriate next step in management?