Reduction of permanent hearing loss by local glucocorticoid application : Guinea pigs with acute acoustic trauma

BACKGROUND

High-intensity noise exposure from impulse and blast noise events often leads to acute hearing loss and may cause irreversible permanent hearing loss as a long-term consequence. Here, a treatment regime was developed to limit permanent damage based on a preclinical animal model of acute noise trauma.

AIM

To develop clinical trials for the treatment of acute noise traumas using approved drugs. The otoprotective potential of glucocorticoids applied locally to the inner ear was examined.

MATERIALS AND METHODS

A series of experiments with different impulse noise exposures were performed. Permanent hearing loss and hair cell density were assessed 14 days after exposure. Hearing and hair cell preservation were investigated as a function of the glucocorticoid dose.

RESULTS

After impulse noise exposure, local application to the round window of the cochlea of high-dose prednisolone (25 mg/ml) or methylprednisolone (12.5 mg/ml) resulted in a statistically significant reduction in hearing loss compared with the control group.

CONCLUSION

The local application of high doses of the drugs to the round window of the cochlea appears to be an effective treatment for acute noise trauma.

[Prediction of round window visibility in cochlear implantation with temporal bone high resolution computed tomography]

Objective: To discuss the prediction of round window(RW) visibility in cochlear implantation(CI) with temporal bone high resolution computed tomography(HRCT). Methods: From January 2013 to January 2017, 130 cases underwent both HRCT and CI in our hospital were analyzed. The distance from facial nerve to posterior canal wall(FWD), the angle between facial nerve and inner margin of round window(FRA), and the angle between facial nerve and tympanic anulus to inner margin of round window(FRAA) were detected at the level of round window on axial temporal bone HRCT. A line parallel to the posterior wall of ear canal was drawn from the anterior wall of facial nerve at the level of round window on axial temporal bone HRCT and its relationship with round window was detected (facial-round window line, FRL): type0-posterior to the round window, type1-between the round window, type2-anterior to the round window. Their(FWD, FRA, FRAA, FRL) relationships with intra-operative round window visibility were analyzed by SPSS 17.0 software. Results: FWD(F=18.76, P=0.00), FRA(F=34.57, P=0.00), FRAA (F=14.24, P=0.00) could affect the intra-operative RW visibility significantly. RW could be exposed completely during CI when preoperative HRCT showing type0 FRL. RW might be partly exposed and not exposed when preoperative HRCT showing type1 and type2 FRL respectively. Conclusion: FWD, FRA, FRAA and FRL of temporal bone HRCT can predict intra-operative round window visibility effectively in CI surgery.