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

Analysis of the effect of reconstructing the ossicular chain under otoendoscopy with and without a stapes superstructure

BACKGROUND

Numerous studies have been conducted on the effect of the stapes superstructure after ossicular chain reconstruction, but the findings are not uniform.

OBJECTIVE

To compare the hearing outcomes of ossicular chain reconstruction with partial ossicular replacement prosthesis (PORP) or total ossicular replacement prosthesis (TORP) under otoendoscopy.

MATERIALS AND METHODS

The records of 111 patients diagnosed with chronic suppurative otitis media were retrospectively analyzed. These patients were divided into PORP group (n = 57) and TORP group (n = 54). They were further subdivided into subgroups PORP-a (with a malleus handle) and PORP-b (without a malleus handle), subgroups TORP-a and TORP-b. Pre- and postoperative audiometric results were analyzed.

RESULTS

The mean postoperative air conduction hearing thresholds improvement, mean air-bone gap improvement, and the success rate of reconstruction were significantly higher in the PORP group than in the TORP group (p < .05). The mean postoperative air conduction hearing thresholds improvement and the success rate of reconstruction were significantly higher in the PORP-a group than in the TORP-a group (p < .05); and similar results were concluded in comparison of the PORP-b group and the TORP-b group.

CONCLUSIONS AND SIGNIFICANCE

The stapes superstructure has an important positive effect on the postoperative outcome of endoscopic ossicular chain reconstruction.

Comparison of partial vs. total ossicular chain reconstruction using titanium prosthesis: a retrospective cohort study

PURPOSE

Comparison of the hearing outcomes of titanium partial ossicular replacement prosthesis (PORP) vs. titanium total ossicular replacement prosthesis (TORP) with footplate shoe (Omega Connector) in second stage ossicular chain reconstruction surgeries.

METHODS

In this retrospective cohort study in a tertiary hospital, we compared the hearing outcomes in 248 patients who had undergone ossicular chain reconstruction with titanium prostheses PORP (n = 115) vs. TORP (n = 133) from August 2017 to June 2021. Pre-and post-operative audiometric data were assessed.

RESULTS

In general, we found that there were no significant differences between PORP and TORP groups in gains of BC (P = 0.080), AC (P = 0.454), ABG (P = 0.928), SRT (P = 0.065), and SDS (P = 0.363). There were no significant differences in terms of ABG gain between the two groups. Regarding ABG gains frequency-specific analysis in the ears with pre-operative conductive hearing loss, there were no significant differences between low-frequencies (P = 0.260) and high-frequencies (P = 0.973) between the two groups.

CONCLUSION

To sum up, this research provided additional evidence with respect to hearing outcomes after staged ossicular chain reconstruction with PORP and TORP. The practical application of our study is that TORP with footplate shoe (Omega Connector) is comparable with PORP in staged ossiculoplasty.

Methods for the calibration of bone conduction transducers at frequencies from 5 to 20 kHz

Techniques for standardizing the output of bone conduction transducers over the 5-20 kHz range are presented. The techniques include definitions of the standard artificial mastoid (AM) impedance and force sensitivity in that high-frequency range using an impedance head coupled to a vibration source. The AM impedance is shown to vary with the contact area of the vibration source. The AM force sensitivity does not vary with the contact area but does exhibit sharp frequency dependences over the 14-20 kHz range. The sharp frequency dependence complicates the use of the AM force sensor as a stand-alone calibration device at these high frequencies. An alternative calibration scheme that uses an accelerometer interposed between the vibrator and the AM impedance is described. Comparisons of the two schemes demonstrate that the accelerometer method produces more consistent results. Comparisons of the force and acceleration output of one bone conduction vibrator at high frequencies suggest those outputs depend on the driven load. The loads used in the two calibration schemes are compared to what is known of the impedance of the skin-covered head.

Does stapedotomy improve high frequency conductive hearing?

OBJECTIVES

Stapedotomy is performed to address conductive hearing deficits. While hearing thresholds reliably improve at low frequencies (LF), conductive outcomes at high frequencies (HF) are less reliable and have not been well described. Herein, we evaluate post-operative HF air-bone gap (ABG) changes and measure HF air conduction (AC) thresholds changes as a function of frequency.

METHODS

Retrospective review of patients who underwent primary stapedotomy with incus wire piston prosthesis between January 2016 and May 2020. Pre- and postoperative audiograms were evaluated. LF ABG was calculated as the mean ABG of thresholds at 250, 500, and 1000 Hz. HF ABG was calculated at 4 kHz.

RESULTS

Forty-six cases met criteria. Mean age at surgery was 54.0 ± 11.7 years. The LF mean preoperative ABG was 36.9 ± 11.0 dB and postoperatively this significantly reduced to 9.35 ± 6.76 dB, (P < .001). The HF mean preoperative ABG was 31.1 ± 14.4 dB and postoperatively, this also significantly reduced to 14.5 ± 12.3 dB, (P < .001). The magnitude of LF ABG closure was over 1.5 times the magnitude of HF ABG closure (P < .001). The gain in AC decreased with increasing frequency (P < .001).

CONCLUSION

Hearing improvement following stapedotomy is greater at low than high frequencies. Postoperative air bone gaps persist at 4 kHz. Further biomechanical and histopathologic work is necessary to localize postoperative high frequency conductive hearing deficits and improve stapedotomy hearing outcomes.

LEVEL OF EVIDENCE

4, retrospective study.