Otosclerosis is an ear disease which causes hearing loss. Our ear is divided into three parts- the front ear, middle ear, and inner ear. The middle ear is the area behind the eardrum and it has tiny bones, the sound waves are amplified by them.
In Otosclerosis case there is abnormal growth of bone within middle ear that stops these bones from vibration. This is the reason for hearing loss because of the sounds waves unable to reach the inner ear.
The sense of balance may likewise be influenced if the unusual bone development stretches out into the internal ear. Find out what are the causes and symptoms of Otosclerosis and how it can be treated.
Pathophysiology Of Otosclerosis
Generally, bone remodeling occurs at a rate of 10% per year throughout skeletal regions. However, a normal otic capsule has very little bone remodeling, only 0.13% per year.
But bone remodeling within the otic capsule is increased in the patients with Otosclerosis. This leads to accumulation of bone deposits that damage audiological structures and worsen normal sound transmission.
Abnormal bone remodeling occurs in three phases-
- Otospongiosis phase – It represents an increase in both osteoclast activity and microvascularity.
- Transitional phase – It begins with deposits of spongy bone by osteoblasts in areas of previous bone reabsorption.
- Otosclerosis phase – In this phase, spongy bone deposits develop into dense bone that narrows the microcirculation developed in the Otospongiosis phase.
Causes of Otosclerosis
Otosclerosis is often hereditary, although isolated cases do happen. For example, a few associations with measles and pregnancy have been seen as intensifying the instance of otosclerosis. both ears might be affected however it is more typical for one ear to be extremely influenced than the other. In the event that left untreated, hearing misfortune ordinarily compounds logically until the point when late middle age when complete deafness happens.
The most famous otosclerosis casualty is said to have been Beethoven. Deafness made him unfit to hear his late compositions.
To whom does Otosclerosis affect?
Otosclerosis affects more than 3 million Americans. Experts aren’t sure exactly what causes it. But they do know:
- You can develop otosclerosis between the ages of 10 and 45, but you’re most likely to get it during your 20s. Symptoms usually are at their worst in your 30s.
- About 50% of all people with otosclerosis have a gene that’s linked to the condition. But even if you have the gene, you won’t necessarily get it.
- Women, though, have a higher risk. Experts aren’t sure why, but if you’re a woman and develop otosclerosis during pregnancy, you’re likely to lose your hearing faster than if you were a man or you weren’t pregnant.
- About 10% of Caucasians develop otosclerosis. It’s less common in other groups and rare for African-Americans.
Conductive (Middle Ear) hearing loss
In Conductive Hearing Loss, the ability of transmission of sound waves from the outer or middle ear to inner ear is reduced or blocked. This is due to the damage to the ossicles. It decreases the efficiency of sound transmission from the outside world to the inner ear. It is the most common symptom of Otosclerosis.
Sensorineural (inner ear) hearing loss
Sometimes abnormal or damaged bone metabolism go on to affect the inner ear. This leads to Sensorineural hearing loss. In this, a person lost their ability to understand sounds clearly.
Tinnitus is the perception or sensation of a ringing or buzzing sound in the ear. It can occur in many ear conditions and is often but not always present in Otosclerosis.
It is a very rare symptom of Otosclerosis and is usually mild.
Otosclerosis is traditionally analyzed by the specialist, which incorporate dynamic conductive hearing loss, a typical tympanic layer, and no proof of center ear irritation.
Roughly 0.5% of the people will inevitably be determined to have otosclerosis. After death contemplates demonstrate that upwards of 10% of individuals may have otosclerosis sores of their temporal bone, however, clearly never had indications justifying a conclusion.
In clinical practice otosclerosis is experienced about twice as often in females as in guys, however, this does not mirror the genuine sex proportion. At the point when families are explored, it is discovered that the condition is just marginally more typical in women.
Audiograms have traditionally been used to diagnose Otosclerosis. It measures air and bone conductions and interactions throughout various frequencies (Hz) at various loudness levels (dB). If an Audiogram results in the hearing threshold greater than 25 dB, then it is abnormal.
The reason why otosclerosis can be monitored by audiogram is that it’s progression directly correlates to hearing loss. A low frequency mild conductive loss occurs when the ossicles become rigid and the connection between the stapes and the oval window begins to change. The value of the air-bone gap (the difference between air and bone conduction) greater than 10 dB is considering abnormal. If cochlear lesions develop, high-frequency sensory loss results in a mixed sensorineural and conductive hearing loss pattern on the audiogram. Extensive progression in cochlea results in a mixed hearing loss in all frequencies.
Tympanometry is not a hearing test. Rather it’s a measure of energy transmission through the middle ear. Tympanograms are 0ften normal in patients with otosclerosis. Only in the case of extensive level of otosclerosis that patient’s tympanogram displays some flattening secondary to severe ossicular chain fixation.
High-resolution CT has been started to be used in the diagnosis of otosclerosis due to improvements in technology allowing for identification of smaller bony lesions. It can reveal variants in patient anatomy and the severity of the disease. Diagnosis of otosclerosis using CT imaging can find the problems in the areas of increased bony radiolucency in the otic capsule around the anterior footplate, thickening of the stapes, and widening of the oval window. The high cost is the main disadvantage of the diagnosis technique.
Treatment of Otosclerosis
Otosclerosis treatment includes four methods –
Do nothing (conservative approach)
Sometime Otosclerosis treatment is not necessary. Specialist just gives the advice to repeat the hearing test once in a year (or earlier if worse hearing).
Hearing Aids cannot treat otosclerosis, but they can reduce the major symptom – hearing loss. The latest technology can help in correcting the hearing loss due to otosclerosis, and may even provide the least invasive and risky solution.
Sometimes, the doctor prescribes Sodium Fluoride in conjunction with Vitamin D. This helps to slow the loss of hearing. Otofluor (contains sodium fluoride) is one treatment for otosclerosis. Second treatment has also been claimed recently which is bisphosphonate medications. It inhibits bone destruction. There are several side-effects to medical treatment. The side-effects may include unusual stomach upset, allergic itching, and increased joint pains which can lead to arthritis. Bisphosphonates, in the worst case, may also lead to bone infarction (death of bone tissue due to interruption of blood supply). So, neither approach is proving beneficial after surgical treatment has come into action.
Patients with otosclerosis who have profound hearing loss have derived significant benefits from cochlear implants. But there is an increased risk of cochlear ossification and facial nerve stimulation before an operation.
In 1957, Dr. John Shea invented the Procedure of stapedectomy for the conductive hearing loss, which hearing results were very effective, that remain effective for a long time after the surgery. In the process of this surgery by removing the stapes bone and change with a prosthetic device.
This surgery is partial removal of the stapes bone for implantation of a prosthetic device and has similar results. Surgery is performing with laser dissection.
In this surgery, all parts of the immobilized stapes bone removed and replaced with a prosthetic device. A surgeon uses an operating microscope to perform surgery through the ear canal. The prosthetic device allows the bones of the middle ear (malleus, incus, and stapes) to resume movement, which stimulates fluid in the inner ear and improves or restores hearing.
Otosclerosis often occurs in both the ears. The ears are operating one at a time. Before performing surgery on the second ear, the surgeon usually waits a minimum of six months.
Complications of Stapedectomy
Following are the risks of Stapedectomy-
Dizziness is normal during the first few days after the operation. It may also result in nausea and vomiting. Prolongation of dizziness is very rare.
It can worsen in rare cases but generally, it improves after the surgery with an improvement in hearing impairment.
A hole in the eardrum during or after surgery is very rare. It usually occurs due to an infection.
In less than 1% of cases, the hearing may be damaged despite a perfect surgery. You have to give a few days of time to the ear to heal completely.
Temporary taste change
One of your taste nerves runs under your eardrum. For surgery, the surgeon may need to move this nerve out of the way. This could results in a temporary taste change on the side of your tongue or loss of taste.
To reduce the risk of complications after surgery:
- Avoid people with respiratory or other infections.
- DO not blow your nose for 2 to 3 weeks after surgery.
- Avoid bending, lifting, or straining as it may cause dizziness.
- Avoid loud noises and sudden pressure changes, such as scuba diving, flying, or driving in the mountains until you have healed.
Otosclerosis causes hearing loss but advancements in diagnostic treatment and technology have made it a treatable disease. Different treatments including medications, surgery, cochlear treatment are available for otosclerosis. Understanding this disease will definitely lead to earlier diagnosis and treatment of the patients.
Read More: Complete therapy of tinnitus