OTOSCLEROSIS TREATMENT

Timothy C. Hain, MD . •Otosclerosis in general• December 3, 2022

There are four treatment options:

1. Do nothing is often reasonable.

Otosclerosis does not have to be treated, as there are no medications that have been shown to work, and it will progress or not independent of any treatment. It is advisable to have a formal hearing test repeated once a year (or earlier if hearing drops). The main reason for this is to exclude alternatives (such as tumors, middle ear infection or fluid, or Menieres-- otosclerosis does not protect you from other ear diseases), and also to keep in touch in regards to when a hearing device might be indicated.

2. Hearing aids --  A good idea if you have enough hearing loss to make it cost effective (usually a PTA > 35).

Hearing aids are effective for conductive hearing loss and certainly are less risky than having ear surgery. Hearing aid technology has undergone tremendous advances since the invention of surgical treatment for otosclerosis.

Bone implanted hearing aids (BAHA), can be especially convenient. They can be "equalized" and "programmed" to adapt to the precise type of hearing loss - -this is of course not possible with a stapedectomy (see below). However, they do involve some surgery, and there is a need for a device to be "attached" to the head.

Cochlear implant (CI) is a more invasive method than the BAHA for improving hearing. According to Atanasova-Koch and Issing (2021), "Otosclerotic patients showed similar surgical outcome in comparison to the controls. A low frequency (13.6%) of facial nerve stimulation was observed in otosclerosis. A significantly higher (p = 0.014) number of deactivated electrodes (4.3%) in subjects with otosclerosis in comparison to non-otosclerosis patients (1.6%) was found. A trend of less speech discrimination of monosyllabic words (65%) in otosclerosis than in non-otosclerosis patients (80%) (p = 0.109) and no difference in the postoperative auditory assessment with regard to the disease grade and electrode disabling was found."

It is hard for the author to see a rationale for using a CI in most cases of otosclerosis, given that BAHAs have such an excellent outcome with lower risk. However, sometimes otosclerosis patients get little benefit from a hearing aid.

Kondo et al (2022) reviewed CI in "far advanced otosclerosis", which has a rationale as there is also a sensorineural hearing loss. They reported: " Pooled rates of FNS were 18% (95% confidence interval, CI 12%-27%) and the rate of partial insertion was 10% (95% CI 7%-15%)." FNS refers to facial nerve stimulation (one doesn't want this), and partial insertion is also not desirable. They also concluded that "Cochlear implantation in FAO demonstrates significant gains in speech discrimination scores with higher rates of FNS and partial insertion. Laryngoscope, 2022."

 

3. Medical treatment -- is generally ineffective

Lictor (2013) reviewed all medical treatments and concluded that there is no medical treatment proven to work. Still, we will review the treatments that have been offered in the past and sometimes are still being prescribed.

Fluorides:

At the present writing, fluoride therapy is no longer a recommended primary treatment for otosclerosis (NIH consensus), because of its effect on other bones including the possibility of increasing the risk of hip fractures. (Riggs et al, 1987; Riggs et al, 1990). It would seem to us, that one would need to consider both the risk of hearing progression, and balance it against the risk of adverse effects on other bones, when prescribing.

Sodium fluoride is a dietary supplement (not a drug). The idea of using fluoride is not unlike that of using it for teeth -- fluoride speeds up hardening of bone. A large uncontrolled study of about 1500 patients by Dr. Shambough and associates (at Northwestern University) suggested that it was effective. Nevertheless, this treatment is not widely accepted and has not been proven to be effective. Other more rigorous trials have reported similar results (Bretlau et al, 1989). Some advocate using sodium fluoride for cochlear otosclerosis (Lippy and Berkowitz, 2008). Cruise et al (2010) indicated that there is only low-quality evidence for sodium fluoride therapy being effective in otosclerosis.

The protocol for medical treatment is to use 2-4 tablets/day of Florical plus 400 U of vitamin D. Side effects of fluoride (Florical and Monocal are the two preparations available over the counter) include occasional stomach upset, allergic itching, and increased joint pains. If aggravation of arthritis occurs, the Fluoride is stopped and the joints return to their previous state in a few weeks. In such a situation, patients can "pace themselves", taking as much of the medication as can be tolerated. Monical is a preparation that is absorbed in the intestine rather than in the stomach and may cause less side effects.

Typical doses are one tablet three times a day (florical) and one-two tablets three times a day (Monocal). Adolescents are treated with 2.2 mg/day of sodium fluoride (Lippy and Berenholtz, 2008). After two years of fluoride treatment, the dose of fluoride is reduced from three times a day to once a day. Once the otospongiosis phase of otosclerosis is over and there is a clear cut otosclerosis documented by conductive hearing loss, fluoride may be stopped. The treatment is continued after surgery.

Biphosphonates:

Brookler has advocated use of medications designed for osteoporosis, the diphosphonate family in otosclerosis (e.g. Brookler, 1997; 2008). A double blinded study found no significant difference (Kennedy et al, 2003). Some studies even report worsening of hearing on these drugs (Yasil et al, 1998), which would be expected if the drug was ineffective. There is also concern about complications, especially involving the bones in the jaw. At this writing (2011), it is not clear whether these drugs are helpful.

Lippy and Berenholtz suggest adding Caltrate and 30 mg of risedronate (a biphophonate -- Actonel) in persons who do not respond to Florical and Vitamin D. In other words, a combined approach. To our knowledge, there has been no controlled studies of this suggestion.

Diphosphonates have been associated in rare instances with osteonecrosis of the jaw as well as unusual femoral shaft fractures.  As there is no FDA approval for these drugs in otosclerosis, we advise caution.

Other approaches:

4. Surgical treatment -- Stapes surgery -- fading out ?

John Shea

For conductive hearing loss, in 1957, Dr. John Shea popularized the procedure of stapedectomy, which produced excellent hearing results, which remain good for many years after the surgery. Historically, Dr. Sam Rosen was the first to suggest mobilization of the stapes.

 

This procedure may allow avoidance of hearing aids. It, however, does not help the sensory component of the hearing loss and at best, may close the "air-bone" gap. It also does not affect the vertigo that is sometimes associated with otosclerosis. According to Lailach et al (2017), "Disease-specific HRQOL improved significantly after stapes surgery in all scales of the SPOT-25. Postoperatively, the total score and the subscore "hearing function" correlated well with the audiometric data. The subscores "tinnitus", "social restrictions", and "mental condition" did not show significant association with audiometric parameters. " So in other words, the surgery improves hearing, but not much else.

According to Nadol, stapedectomy is indicated in patients with good  bilateral inner-ear function, and conductive hearing loss ranging from 25-30 dB. Stapedectomy is unreasonable if discrimination scores are lower than 65% as this indicates that there is a substantial sensory component.  Patients with stapedectomy may attain better results with hearing aids because of the need for lessor amplification.

There are several types of prostheses. Most current stapes of pistons use titanium or platinum which are MRI safe. Stainless steel wires are less commonly used as they tended to develop the "loose wire syndrome" (Sargent, 2022).

prosthesis

A CT scan of the an ear with a prosthesis on the left is shown above. The image on the left is the axial, and on the right is the coronal. This prosthesis has stayed in place for many years.

TORP TORP place Torp dislocated
TORP -- total ossicular replacement prosthesis Prosthesis in place (CT scan of temporal bone) Displaced prosthesis (CT scan temporal bone, same patient as on L, 1 year later). Note that the small end of the prosthesis is no longer adjacent to bone, and also that the entire prosthesis has rotated about 45 degrees clockwise.

A TORP (total ossicular replacement) is shown above. This prosthesis has migrated out of position and is no longer properly placed.

According to Dr. Sargent (2022), "Overclosure: defined as an >10-dB improvement in bone conduction hearing after stapedectomy; represents improvement in the middle ear mechanics with a freed ossicular chain; overclosure (negative or positive) occurred in ≈92% of patients in the speaker's series; a positive overclosure occurs at very high frequencies."

Stapedectomy may fail for a number of reasons. It is a somewhat difficult and delicate procedure. There may be displacement of the prosthesis (as shown above), reclosure of the fenestra (window), or erosion of the incus. If the prosthesis migrates inward, then ear drum movement may directly stimulate the saccule utricle. (see Shohet et al, 2022) If it migrates outward, a fistula can arise at the oval window, from which the prosthesis was dislodged. The mobilized footplate may migrate into the vestibule (called "floating footplate"). This can result in immediate loss of hearing.

A "perilymph gusher" is another rare possibility. This is seen more often in persons with congenital ear disorders, and may be due to a widened vestibular aqueduct or a defect in the fundus of the IAC.

Other possibilities is that the facial nerve may be damaged or block access to the stapes. According to Shea (2001), about 0.5% develop a "delayed facial palsy" 5-16 days Post-Op.

Serous labyrinthitis is common after surgery and causes a transient unsteadiness, vertigo and slight high frequency hearing loss.

Long term problems:

Migrated prostheses
Migrated prostheses
Migrated prostheses are seen within the vestibule on this CT scan of a patient who had stapes surgeries done on both sides, about 50 years ago.

 

Disease may progress so that correction of the conductive component is inadequate. This is called "refixation". This is more common in persons with more severe disease -- "obliterative otosclerosis". At least 10-20% of patients undergo revision surgery (Mayer and Lambert, 2004). Displacement of the prosthesis is much more common however than progression of otosclerosis.

Hearing loss typically progresses after surgery, with the sensorineural component progressing at the rate of 1 dB/year (Sakihara and Parving, 1999).

Stapes surgery is decreasing (Vrabec and Coker, 2005). This may be due to increasing prevalence of measles immunization, catching up on the backlog of cases that existed before surgery was available, or just changes in how conductive hearing loss is treated.

The author's advice on stapedectomy (the author is not an otologic surgeon), is that the BAHA implanted hearing aid, as well as similar devices, seem better suited to treatment of otosclerosis and similar causes of conductive hearing loss than stapes surgery. Devices like the BAHA have less risk of dizziness or failure, and more control over the outcome. One can always readjust the tuning of the BAHA. There is not much one can do about a failed stapes procedure other than take more CT scans, adding on more radiation, and then do more surgery.

Surgery pearls (From Lippy and Berenholz, 2008).

Surgery should not be done if the air-bone gap is less than 20 DB. Always test each patient at least twice before doing the surgery (because mistakes can happen). The surgeon should be prepared, if necessary, to repair the ear drum prior to the operation, treat all infections prior to the operation, and remove exostoses at the time of the ear surgery.

Surgery should not be performed on a patient with present acoustic reflexes. We ourselves would modify this to say that acoustic reflexes should be either absent or inverted.

Surgery should also not be performed in patients whose hearing loss is 70 dB or less unless their speech discrimination score is 80% or better.

Revision surgery.

Otosclerosis surgery is not durable. The disease tends to progress. On revision, "success" rates are approximately 75%. (Lippy and Berenholz, 2008)

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