OBJECTIVE: To investigate a pathology of conductive hearing loss caused by an incomplete ossicular discontinuity. It can manifest as a triad of the following: 1) conductive hearing loss most prominent in the high frequencies (hfCHL), defined as [ABG for 4 kHz] > [mean ABG for 0.25-0.5 kHz] + 10 dB or more; 2) fluctuating hearing loss; and 3) short-lasting improvement of hearing after Valsalva maneuver.
STUDY DESIGN: Retrospective clinical trial.
SETTING: Tertiary referral center.
PATIENTS: Fourteen patients with an incomplete ossicular discontinuity who underwent incus interposition were included.
INTERVENTION: Incus interposition, mathematical model.
MAIN OUTCOME MEASURES: First, the prevalence of the triad was documented. Second, the hypothesis that mechanical ossicular compliance was responsible for the triad of symptoms was evaluated and simulated in a mathematical model. Finally, the postoperative hearing results with a follow-up of 12 months were analyzed and compared with those reported in the literature.
RESULTS: The presence of the triad of symptoms is a strong indicator for detecting patients with an incomplete ossicular discontinuity. High frequency conductive hearing loss was present in 93% (13/14 patients). Ten (71%) of the 14 patients presented with fluctuating hearing loss and improvement of hearing after Valsalva maneuver. The hfCHL could be simulated adequately in the mathematical model. Success rate for surgical intervention (ABG < 20 dB; 0.5, 1, 2, and 3 kHz) was 93% and was comparable to the results reported in the literature.
CONCLUSION: Patients with hfCHL, fluctuating hearing loss, and improvement of hearing after Valsalva maneuver are likely to have an incomplete ossicular discontinuity. A favorable postoperative hearing recovery by incus interposition can be expected.