What “far-advanced” means
Most people with otosclerosis have a conductive loss: the stapes is fixed, the inner ear is healthy, and a hearing aid or a stapedotomy works well. In a minority the disease goes further. The loss becomes severe or profound, and even a powerful hearing aid no longer makes speech clear.
The term far-advanced otosclerosis goes back to House and Sheehy in the early 1960s. Their criteria were audiometric: air conduction worse than about 85 dB, and bone conduction too poor to measure. Today the working definition is usually functional: poor speech understanding despite well-fitted hearing aids, the point at which a cochlear implant becomes a realistic alternative.
“Unmeasurable” does not mean “absent”. A bone vibrator cannot produce sound as loud as headphones, so in a severe loss the bone-conduction thresholds simply run off the chart. Behind that limit there may still be an air-bone gap: a conductive part of the loss that surgery could close. Its size cannot be read from the audiogram, and that hidden quantity is what makes the decision difficult.
Cochlear otosclerosis
Otosclerosis usually stays near the oval window, where it fixes the stapes. In some ears, foci also develop in the bony capsule around the cochlea itself (cochlear or retrofenestral otosclerosis), and the inner ear gradually loses function. The result is a mixed loss: conductive from the fixed stapes, sensorineural from the cochlea. Why this happens in some people and not in others is not well understood.
A high-resolution CT scan of the temporal bones is the key investigation. Active otosclerotic bone is less dense than the normal capsule; around the cochlea it can show as a dark band encircling the cochlear turns, the double-ring sign. CT also shows how far the disease has spread, whether the round window (the usual entry point for an implant electrode) is narrowed or closed by new bone, and whether the cochlear spaces are still open.
Medication (sodium fluoride or bisphosphonates) is sometimes used to try to slow cochlear otosclerosis; it does not restore hearing and the evidence is weak (see treating otosclerosis without surgery).
Two strategies
Stapedotomy first, then a powerful hearing aid
The operation is the same stapedotomy used for ordinary otosclerosis, but the aim differs. It is not meant to free the person from a hearing aid; it removes the conductive part of the loss so that a powerful aid has something to work with again. If a hidden gap is closed, a loss of 110 dB may become one of around 80 dB: still severe, but within reach of a good hearing aid.
The clearest summary is a 2014 meta-analysis by van Loon and colleagues, limited to people who already met cochlear implant criteria (aided speech recognition of 50% or less). After stapedotomy and a refitted hearing aid, average speech recognition rose from 11% to 59%, and about seven in ten no longer met the implant criterion. The series were small, but the direction is consistent.
In its favour: a shorter operation, natural acoustic hearing, low cost and, in bilateral disease, the chance of two hearing ears. Against it: unpredictability, and the usual stapedotomy risks, including severe inner-ear loss in about 0.5–1% of first operations. In a pooled analysis, revision was also needed more often after stapes surgery than after implantation.
A cochlear implant directly
A cochlear implant bypasses both the fixed stapes and the damaged hair cells and stimulates the hearing nerve directly. Its results are more predictable. In a series of 58 patients with far-advanced otosclerosis, 85% of implanted patients reached word recognition above 50%, against 60% after primary stapedotomy. A meta-analysis of 26 studies found better hearing thresholds and higher satisfaction after implantation, with similar or slightly higher word scores after stapes surgery, and judged both to be reliable options. A 2025 cohort study found that five years after implantation, people with far-advanced otosclerosis understood speech as well as implant users deafened by other causes.
The costs are a longer operation under general anaesthesia, a device for life, months of rehabilitation while the brain learns to use electrical hearing, and usually the loss of whatever natural hearing remains in that ear. Otosclerosis adds two specific problems.
Cochlear implants in otosclerosis: two specific problems
Facial nerve stimulation. The facial nerve runs close to the cochlea. Spongy otosclerotic bone conducts electrical current more readily than normal bone, so current from some electrodes can reach the nerve and cause twitching of the face or eyelid with sound. In one large series of 91 ears implanted for far-advanced otosclerosis, it occurred in 21%, sometimes years after implantation, and more often when CT showed extensive disease. It is usually managed by reprogramming the implant and switching off the electrodes responsible; no implant in that series had to be removed. Over the years, though, speech performance tended to decline in these ears, probably because fewer electrodes remained active. Reported rates vary widely between studies.
Cochlear ossification. New bone can narrow or close the round window and the first turn of the cochlea, which makes full insertion of the electrode harder. In the meta-analysis, insertion was reported as difficult in about 15% of implantations. Rarely, a stapedotomy complicated by inflammation of the inner ear leads to rapid scarring and bone formation inside the cochlea, which can jeopardise a later implant. This is one reason the order of treatments matters (see cochlear hearing preservation).
How the decision is reasoned
There is no randomised trial, and surgeons differ. Some offer stapedotomy first to nearly everyone, keeping the implant in reserve; others favour direct implantation when speech understanding is already very poor. Merkus and colleagues in Amsterdam proposed an algorithm built on three measurements: the speech discrimination score, the CT classification and the air-bone gap. The reasoning usually runs as follows.
- Speech understanding with a well-fitted, powerful hearing aid. Thresholds alone mislead; the decisive measurement is word recognition with the aid in place. Implant criteria are usually around 50% or less with optimally fitted aids, and differ between countries. See speech understanding.
- Residual hearing and any measurable gap. Measurable bone conduction, a low-frequency air-bone gap, or speech that is still partly understood suggest that the cochlea still has something to give, which favours trying stapedotomy. See residual hearing.
- The CT scan. Extensive cochlear disease and an obliterated round window make implant surgery harder and facial stimulation more likely. Whether CT predicts the result of a stapedotomy is less clear.
- Time. In one series, profound deafness for more than five years and a previous stapedotomy were both linked to lower speech scores a year after implantation; the 2025 cohort found the same for previous stapedotomy at five years. Other studies found no stapedotomy effect. Trying stapedotomy first is reasonable, but a failed attempt should not be followed by years of waiting.
- The other ear. Otosclerosis affects both ears in most people, and the second ear shapes the plan: stapedotomy on both sides, stapedotomy on one and an implant on the other, or two implants. Two hearing ears help most with speech in noise and with locating sound, the situations in which the author’s Utrecht group’s randomised trial of one versus two cochlear implants found binaural benefit (see research, bilateral otosclerosis and binaural hearing).
- The person. Willingness to accept a second operation if the first does not help, the time and support needed for implant rehabilitation, access and cost, and how much a natural acoustic sound matters.
CT staging and the numbers behind the comparison
CT: several three-stage classifications are used (window disease only; pericochlear foci without endosteal involvement; endosteal involvement with loss of cochlear architecture). In 91 ears implanted for FAO (Tuset et al.), stage III disease was present in 68% of ears that developed facial nerve stimulation against 25% of those that did not; the position of foci relative to the facial canal did not predict it. Cumulative incidence of stimulation reached 33% at 15 years. Kabbara et al.: surgical difficulty rose with radiological stage, but no predictor of stapedotomy failure was found; mean WRS 50.6% after primary stapedotomy (n = 32), 75% after primary CI (n = 9), 72% after CI following stapedotomy (n = 25). Teaima et al. (26 mostly retrospective studies): revision 8.1% versus 16.4%; pooled facial nerve stimulation after CI 12.4%. Quatre et al.: 5-year speech 48.6% (41 FAO) versus 48.2% (73 controls); 39.3% with versus 57.5% without previous stapedotomy.
After the decision
Whichever route is chosen, success is measured as speech understanding in quiet and in noise with the device in use, not only as an audiogram. After a stapedotomy the hearing aid is refitted once the ear has settled (see stapedotomy recovery). A sudden drop in hearing or severe, spinning vertigo after ear surgery needs the surgeon the same day; see when to contact your surgeon. Twitching of the face with sound after implantation should be reported to the implant team; it can usually be managed by reprogramming.
Sources
- Sheehy JL. Far-advanced otosclerosis; diagnostic criteria and results of treatment; report of 67 cases. Arch Otolaryngol. 1964;80:244-9. PubMed
- Goh JP, Chan LL, Tan TY. MRI of cochlear otosclerosis. Br J Radiol. 2002;75(894):502-5. PubMed
- Merkus P, van Loon MC, Smit CF, Smits C, de Cock AF, Hensen EF. Decision making in advanced otosclerosis: an evidence-based strategy. Laryngoscope. 2011;121(9):1935-41. PubMed
- van Loon MC, Merkus P, Smit CF, Smits C, Witte BI, Hensen EF. Stapedotomy in cochlear implant candidates with far advanced otosclerosis: a systematic review of the literature and meta-analysis. Otol Neurotol. 2014;35(10):1707-14. PubMed
- Kabbara B, Gauche C, Calmels MN, et al. Decisive criteria between stapedotomy and cochlear implantation in patients with far advanced otosclerosis. Otol Neurotol. 2015;36(3):e73-8. PubMed
- Teaima AA, Elnashar AA, Hakim EK, Hadaey HS. Comparison of the efficacy of cochlear implantation and stapes surgery in far advanced otosclerosis: a meta-analysis study. Eur Arch Otorhinolaryngol. 2023;280(1):77-88. PubMed
- Tuset MP, Baptiste A, Cyna Gorse F, et al. Facial nerve stimulation in adult cochlear implant recipients with far advanced otosclerosis. Laryngoscope Investig Otolaryngol. 2023;8(1):220-229. PubMed
- Quatre R, Eklöf M, Wales J, Bonnard Å. Long-term hearing outcomes following cochlear implantation in far advanced otosclerosis. Otolaryngol Head Neck Surg. 2025;172(6):2065-2071. PubMed
Common questions
What is far-advanced otosclerosis?
It is otosclerosis that has caused a severe to profound hearing loss, usually because the disease affects both the stapes and the cochlea. The original definition, from the early 1960s, was air conduction worse than about 85 dB with bone conduction too poor to measure. Today it is more often defined by function: speech remains hard to understand even with well-fitted, powerful hearing aids.
Can a stapedotomy still help when hearing is very poor?
Often, yes. A severe loss in otosclerosis may hide a conductive part that the audiometer cannot show. Closing it can bring hearing back within reach of a powerful hearing aid. In a 2014 meta-analysis of people who already qualified for a cochlear implant, about seven in ten no longer met the implant criterion after stapedotomy and a refitted aid. The result is hard to predict for the individual, and a hearing aid is still needed afterwards.
Is a cochlear implant better than a stapedotomy for advanced otosclerosis?
On average, implantation gives more predictable results: more people reach useful speech understanding, and sounds are heard at closer to normal levels. Stapedotomy is a smaller operation that keeps natural hearing and works very well in some ears. No randomised trial has compared the two, and surgeons differ in which they offer first. The speech score with a well-fitted, powerful hearing aid, the CT scan and the other ear usually decide.
If I have a stapedotomy first, can I still have a cochlear implant later?
In most cases, yes; many implant recipients with otosclerosis have had stapes surgery before. Two cautions apply. Rarely, inner-ear inflammation after a stapedotomy causes scarring or new bone inside the cochlea, which makes a later implant harder to place. And some studies found lower speech scores after implantation in people with a previous stapedotomy, or who had been profoundly deaf for more than five years, although others did not.
Why can a cochlear implant make the face twitch in otosclerosis?
The facial nerve runs close to the cochlea, and otosclerotic bone conducts electrical current more easily than normal bone. Current from some electrodes can then reach the facial nerve and cause twitching with sound. This is more common in otosclerosis than in most other causes of deafness, especially when the CT scan shows extensive disease. It is usually managed by reprogramming the implant or switching off the electrodes involved.
Do I need a CT scan before deciding?
A high-resolution CT scan of the temporal bones is standard before either route. It shows how far otosclerosis has spread around the cochlea, sometimes as a dark ring known as the double-ring sign, whether the round window and cochlear spaces are open for an implant electrode, and how extensive the disease is, which relates to the risk of facial nerve stimulation. On its own it does not predict how well a stapedotomy will work.
This page provides general educational information. It cannot replace an individual assessment, which depends on a full history, examination, audiometry and, where relevant, imaging. If you have sudden hearing loss, severe pain, facial weakness, severe dizziness or discharge with fever, seek medical care promptly.