Otosclerosis is a condition characterized by abnormal bone remodeling within the temporal bone, specifically affecting the bone surrounding the inner ear capsule. This disorder leads to progressive hearing loss as the irregular growth interferes with the ear’s ability to transmit sound waves effectively. While the underlying biological disease process cannot be eliminated currently, medical and surgical treatments offer significant relief and functional restoration. This article explores the realistic expectations for treatment and outlines the available management options.
How Otosclerosis Affects Hearing
The disease begins in the otic capsule, the dense bone surrounding the inner ear, where normal bone is gradually replaced by lesions of spongy, irregularly laid bone. This process is sometimes referred to as otospongiosis in its early, active phase.
The most common consequence occurs when this abnormal bone growth reaches and immobilizes the stapes, one of the three middle ear bones. The stapes normally vibrates freely, transmitting sound energy from the eardrum into the fluid-filled inner ear.
Fixation of the stapes footplate to the oval window prevents this movement, causing a conductive hearing loss because sound waves are not physically conducted to the inner ear.
Otosclerosis may also affect the inner ear directly, leading to a sensorineural component of hearing loss. If the abnormal bone remodeling spreads into the cochlea, it can disrupt the function of the sensory hair cells, resulting in a combined, or mixed, hearing loss. This sensorineural element presents a greater challenge for correction, as it involves damage to delicate nerve structures.
Non-Surgical Management Options
For patients with mild hearing loss or those who are not surgical candidates, non-surgical management is the primary approach. Observation is a reasonable option when the hearing loss is slight and not significantly impacting daily life. Regular monitoring tracks the disease’s progression over time.
Hearing aids are often a highly effective intervention for the conductive component of otosclerosis. These devices amplify sounds, which overcomes the mechanical blockage caused by the fixed stapes. Amplification can restore good hearing perception, as the inner ear’s sound-processing ability is often still functional in the early stages.
An audiologist can customize the settings on a hearing aid to meet the specific needs of the hearing loss pattern. This provides an excellent functional solution for many patients, regardless of whether they choose or are eligible for surgical intervention. The use of a hearing aid does not halt the underlying bone remodeling process.
Surgical Intervention and Outcomes
The most definitive treatment for the conductive hearing loss is a surgical procedure called a stapedectomy or stapedotomy. The surgery’s goal is to bypass the fixed stapes bone and restore the transmission of sound to the inner ear.
During the procedure, the surgeon removes the upper part of the fixed stapes and makes a tiny opening in the footplate. A micro-prosthesis, often a Teflon or titanium piston, is then inserted through this opening to replace the function of the stapes.
This prosthetic device connects the incus to the inner ear fluid, allowing sound vibrations to travel unimpeded once again. This procedure functionally corrects the mechanical problem, though it does not stop the biological disease process itself.
Stapedectomy is a highly successful operation, with up to 90% of patients experiencing a significant improvement in their hearing. Success is defined as reducing the air-bone gap—the difference between air-conducted and bone-conducted hearing—to within 10 decibels.
The procedure carries a small risk of complications, including dizziness that usually resolves quickly, taste disturbance from nerve manipulation, and, in a rare 1-2% of cases, further hearing loss.
Living With Otosclerosis
Long-term monitoring is necessary because otosclerosis is a progressive condition that can continue to affect the inner ear or manifest in the other ear over time. Ongoing audiological evaluations ensure that any changes in hearing are detected early, allowing for timely adjustments to the management plan.
In cases where the disease has a significant sensorineural component, researchers are investigating pharmacological approaches. Bisphosphonates, a class of drugs that slow bone remodeling, have been studied for their potential to stabilize hearing loss, especially the sensorineural element.
While current evidence does not support the routine use of bisphosphonates, some long-term data suggests they may help stabilize progressive sensorineural hearing loss in a subset of patients. Further clinical trials are needed to confirm the efficacy and optimal use of drug therapies that target the underlying pathology.