Bonebridge or cochlear implant: Which hearing implant for otosclerosis?

Otosclerosis - treatment options with hearing implants

Otosclerosis is a pathological tissue formation that usually begins at the transition from the middle to the inner ear. Ultimately, it leads to ossification of the middle ear structures.

If the auditory ossicles are no longer mobile, they can no longer fulfill their function of signal transmission and impedance conversion: The consequences range from mild hearing loss to deafness.
ENT specialists often advise observation, and mild hearing loss is often compensated for with conventional hearing aids. In the case of significant conductive hearing loss, the surgeon removes the ossified part during an operation called a stapedectomy or stapesplasty and replaces it with a passive middle ear implant. Many patients then hear better again. However, neither this operation nor a hearing aid helps 10 to 15 percent of patients. Most of these patients can benefit very well from an active hearing implant!

In comparison: Bonebridge or cochlear implant for otosclerosis

Among otosclerosis sufferers, there are well-suited candidates for almost every implant system. Two systems are particularly often suitable:

• The bone conduction implant Bonebridge for predominantly conductive hearing loss
• A cochlear implant, or CI for short, if the inner ear is affected to the appropriate extent.

The bonebridge uses the bone conduction of the human skull bone to bypass the functionally restricted middle ear. It converts sound into mechanical vibrations that are transmitted in the middle ear or at the transition to the inner ear. From there, they travel along the natural path to the healthy inner ear.

If the inner ear can no longer fulfill its function, a CI is indicated. This converts sound into electrical impulses with which it directly stimulates the auditory nerve. This new way of hearing takes some getting used to, but studies show that If a CI is indicated, otosclerosis sufferers are more satisfied with it than with a stapes reconstruction, which is also surgical¹.

How hearing implants help with otosclerosis

None of the interventions mentioned can stop the pathological bone growth. However, hearing can be improved at any stage of the disease with suitable hearing aids in order to avoid subsequent problems. Auditory stimulation counteracts degeneration of the auditory nerve
^{2 3 4} and helps to maintain the cognitive allocation of auditory impressions. Those affected should use suitable hearing aids as soon as possible.

Literature

[1] Kondo M et al. Cochlear Implantation in Far Advanced Otosclerosis: A Systematic Review and Meta-Analysis. Laryngoscope. 2023; 133(6): 1288-1296. doi: 10.1002/lary.30386.

[2] Kopelovich JC et al. Intracochlear electrical stimulation suppresses apoptotic signaling in rat spiral ganglion neurons after deafening in vivo. Otolaryngol Head Neck Surg. 2013 Nov; 149(5): 745-752. doi: 10.1177/0194599813498702.

[3] Chen I et al. The effect of cochlear-implant-mediated electrical stimulation on spiral ganglion cells in congenitally deaf white cats. J Assoc Res Otolaryngol. 2010 Dec; 11(4): 587-603. doi: 10.1007/s10162-010-0234-3.

[4] Fallon JB et al. Effects of chronic cochlear electrical stimulation after an extended period of profound deafness on primary auditory cortex organization in cats. European Journal of Neuroscience. 2014 Mar; 39(5): 811-820. doi: 10.1111/ejn.12445.

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