The role of preoperative, intratympanic glucocorticoids for hearing preservation in cochlear implantation: a prospective clinical study

Abstract

Background: Hearing Preservation is becoming increasingly important in cochlear implantation as there is growing evidence that preserving the residual hearing, especially in the low frequencies in combination with the electric stimulation can significantly improve hearing and speech outcomes in noise. Besides the ongoing development of atraumatic implant electrodes and insertion techniques, the implementation of pharmacologic hair cell protection is thought to increase hearing preservation. This study investigates the effects of preoperative intratympanic glucocorticoid application on hearing preservation rates in cochlear implantation.

Study design: Prospective interventional study.

Setting: Tertiary neurotology referral center.

Patients: Patients undergoing cochlear implantation with measurable preoperative hearing thresholds using either a Flex soft electrode or a Flex EAS electrode depending on the degree of residual low frequency hearing.

Intervention: Preoperative intratympanic steroid application during cochlear implantation via round window insertion.

Main outcome measures: Level of hearing preservation after cochlear implantation; electrode- and frequency-specific hearing preservation rates.

Results: Preoperative hearing thresholds were comparable in the control group and the interventional Flex soft group (70.5 db±12.5 dB vs. 73.5 dB±10.5 dB, P=.27). As per selection criteria the low-frequency hearing thresholds were significantly lower in interventional Flex EAS groups when compared to the control group. Hearing preservation was significantly better in the interventional group with no case of complete hearing loss in this group (11 dB±2.5 dB vs. 19.5 dB 3.5 dB, P<.05). The interventional group displayed a higher stability of hearing preservation after implantation (r=.8, P=.03). Level of hearing preservation was higher when a specific hearing preservation electrode was used (r=.85, P<.05). Hearing preservation in the low frequencies was significantly higher than in the high frequencies.

Conclusions: Our study suggests that the additional preoperative use of intratympanic glucocorticoids improves and stabilizes hearing preservations rates in round window cochlear implantation for adults and children with residual hearing.