Do high‐frequency air‐bone gaps persist after ossiculoplasty?

Abstract

Objectives Conventional reporting of postoperative hearing outcomes utilizes a pure‐tone averaged air‐bone gap (ABG) that is biased toward low frequencies. Consequently, a high‐frequency ABG after otologic surgery may go unnoticed. In this study, we evaluate changes in low‐ and high‐frequency ABG following ossiculoplasty. Study design Retrospective review. Subjects and setting Consecutive series of patients who underwent ossiculoplasty at a single tertiary care center. Patients with pre‐ and postoperative audiograms were included. Methods Low‐frequency ABG was calculated as the mean ABG at 250, 500, and 1000 Hz. High‐frequency ABG was calculated at 4 kHz. Pre‐ and postoperative ABGs were compared. Results Thirty‐seven consecutive patients were included. Mean age at surgery was 38 years (range, 7‐77 years). Reconstruction materials included: cartilage (N = 4), hydroxyapatite cement (N = 5), and partial or total ossicular replacement prostheses (N = 20 and N = 8, respectively). Postoperatively, the mean low‐frequency ABG improved by 11.9 ± 15.1 dB (P < .0001) and the mean high‐frequency ABG improved by 5.9 ± 16.0 dB (P = .030). Low‐frequency ABG closure was significantly larger than high‐frequency ABG closure (P = .007). Mean postoperative persistent high‐frequency ABG was 22.0 ± 13.8 dB. Conclusion In this series, ossiculoplasty improved ABG across all frequencies, but greater improvements were observed at low frequencies when compared to high frequency. Current reporting standards may not identify persistent high‐frequency ABG. Additional study of the mechanisms of high‐frequency sound conduction in reconstructed middle ears is needed to improve high‐frequency hearing outcomes in ossiculoplasty. Level of evidence Level 4.

Hearing outcomes after incudo-stapedial rebridging versus partial ossicular replacement prosthesis in chronic suppurative otitis media

“…A statistically significant improvement in air conduction by 15.14 dB was found after undergoing incudostapedial reconstruction using conchal cartilage (p< 0.001). In agreement with our results, Polanik et al, [9] conducted a retrospective study to evaluate changes in low and high frequency ABG following ossiculoplasty. Reconstruction materials included: cartilage (N = 4), hydroxyapatite cement (N = 5), and partial or total ossicular replacement prostheses (N = 20 and N = 8, respectively).…”

Does stapedotomy improve high frequency conductive hearing?

“…Our secondary analysis of the results from over 700 patients published by Pauli 2019 shows a more complete closure of the ABG at low frequencies than high frequencies with similar magnitudes to our data set. Our prior work on high‐frequency conductive hearing following middle ear surgery 9 , 10 suggests that across middle ear surgical procedures, post‐operative high frequency ABGs persist and may be under‐reported using current PTA 4 standards. 8 …”

“…A 2018 review by Cheng et al, demonstrated the short and long‐term durability of hearing improvements following stapedotomy using PTA data from several published series 6 . However, the traditional pure‐tone average (PTA 4 ) recommended by the American Academy of Otolaryngology‐Head and Neck Surgery (AAO‐HNS), 7,8 may not sufficiently communicate changes in high‐frequency (HF) conductive hearing 9,10 . HF bone conduction thresholds following stapes surgery have not been robustly studied and reported outcomes are variable 5,11‐13 …”

“… 6 However, the traditional pure‐tone average (PTA 4 ) recommended by the American Academy of Otolaryngology‐Head and Neck Surgery (AAO‐HNS), 7 , 8 may not sufficiently communicate changes in high‐frequency (HF) conductive hearing. 9 , 10 HF bone conduction thresholds following stapes surgery have not been robustly studied and reported outcomes are variable. 5 , 11 , 12 , 13 …”