Two ears, rarely equal
Otosclerosis is a disease of the bone around the inner ear, and that bone is present on both sides. In most people the process is found in both ears: in about three-quarters of cases in a large collection of temporal bones examined after death, and in 78% of a hospital series diagnosed by CT scan. The two sides are seldom affected equally. One ear usually loses hearing first and further. The other may follow years later, or may keep hearing normally for life because its stapes never becomes fixed.
That asymmetry shapes every decision. The question is not only “should I have an operation?” but “which ear, in what order, and does the second ear need one at all?” The condition is described on otosclerosis, the operation on stapedotomy.
Why the worse ear goes first
The first operation is normally offered for the worse-hearing ear, provided its inner ear is healthy enough to benefit. There are two reasons, and the second matters more.
First, the worse ear has more to gain. Closing a large air-bone gap changes daily hearing more than closing a small one.
Second, the better ear is the safety net. Stapedotomy carries a small, irreversible risk: severe or total inner-ear hearing loss in about 0.5–1% of first operations. If that happens in the worse ear, the person still has their better ear. If it happened in the better ear, they would be left relying on the poorer one. Operating the worse ear first keeps the possible harm as small as it can be.
The same logic underlies a rule that runs through this site: the opposite ear is never operated until the result of the first is stable.
Waiting for a stable result
The first result needs time to show itself. Hearing usually opens up over several weeks, the air-bone gap is judged on the audiogram at three to six months, and bone conduction, the proof that the inner ear was protected, is measured again once the ear has healed. Most surgeons wait at least six months, and often a year, before discussing the second ear. Practice varies, and no trial has defined the right interval; what matters is that the first ear has settled.
“Stable” means several things together: the gap has closed or nearly closed, bone conduction is unchanged, any dizziness has gone, and the person can say how the operated ear works in daily life. During this period, a sudden change in hearing in the operated ear, or dizziness that persists beyond the first days, is a reason to call your surgeon; severe vertigo or a sudden, complete loss of hearing needs care the same day. See when to contact your surgeon.
The wait has a second purpose: the first operation is also information. The two ears of one person often look alike at surgery. A footplate thickened or obliterated by otosclerosis, a narrow oval-window niche, or a facial nerve lying over the footplate, once found in the first ear, is more likely to be found in the second.
What the second operation achieves
When the first ear has done well and the second ear is a suitable candidate, the second operation gives broadly the same result as the first. In the largest published series, 394 operations on both ears of the same people, the air-bone gap closed to within 20 dB in 98% after the first operation and after the second. The gain in decibels was somewhat smaller in the second ear, which is usually the less affected of the two.
The larger change is in what the person hears with two ears together. In that series, the first operation moved about seven in ten people from a hearing loss in both ears to a loss in one ear only; the second moved about two-thirds to normal and symmetrical hearing.
The risks of the second operation are of the same kind as the first: temporary dizziness, a change in taste, tinnitus, and the small risk of inner-ear loss described on stapedotomy. Published series have not shown the second ear to be at clearly greater risk, but they are too small to measure a risk of 0.5–1% precisely. Two operations mean two exposures to that risk, and that belongs in the discussion before the second is planned.
Two ears working together
The strongest argument for treating the second ear is not found in its own audiogram. The brain compares the two ears to locate sound and to pick out one voice among many, and it does this most reliably when both ears deliver similar signals. With one ear restored and the other still blocked, binaural hearing is only partly back. With both treated, spatial hearing and hearing in noise can recover more fully.
One small study supports this. When people with one successful operation had the second ear done, their understanding of speech in noise improved, measured with loudspeakers around the listener rather than through headphones. The benefit varies between people, but the direction is consistent with what is known about two-eared hearing.
Surgery on one side, a hearing aid on the other
Many people with otosclerosis in both ears choose an operation on one side and a hearing aid on the other, and keep that arrangement for good. It is a legitimate choice, not a half-measure. Because the inner ear is usually healthy, a hearing aid works well in otosclerosis, and an aided second ear restores much of the two-eared input with no surgical risk.
It also keeps options open. If the aid proves unsatisfactory, because of a blocked feeling, the sound of one’s own voice, or practical reasons such as sport or work, surgery on the second ear remains possible later. The two approaches are compared on hearing aid or surgery?.
Not everyone feels the need for either. In a small Italian study, quality of life was similar in people operated on one side and on both, and the authors suggested operating the second ear mainly when the patient asks for it. A good first result can be enough.
When the second ear is better left alone
Some situations argue against a second operation.
- An only-hearing ear. If the first operation caused a severe or total inner-ear loss, a “dead ear”, or the other ear is deaf for another reason, the second ear is the only hearing ear. Such an ear is very rarely operated, because a small risk has become an unacceptable one. A hearing aid on that ear is the usual answer. For the deaf ear, the options are a CROS hearing aid, which routes sound from the deaf side to the hearing ear, a bone-conduction device, or a cochlear implant; see hearing rehabilitation.
- A poor first result. The first task is to understand why. When the cause was specific to that ear, the other ear may well do better, as discussed on revision ear surgery. When the reason is unexplained, operating the second ear risks repeating it.
- An excellent hearing-aid result. If an aid in the second ear gives clear, comfortable hearing, surgery has less to add, and the risk is unchanged.
- A difficult first ear. An obliterated footplate or an exposed facial nerve in the first ear predicts a more difficult second ear. That does not rule surgery out, but it changes the balance.
Second-ear surgery: what the series show
Footplate pathology is markedly symmetrical: in 269 patients who had both ears operated, the severity of the footplate lesion and narrowing of the oval-window niche in the first ear predicted the findings in the second (Gristwood and Bedson). In 459 patients operated bilaterally (Shine et al.), an obliterated footplate and a drill-out in the first ear predicted the same in the second; a drill-out carried roughly three-fold odds of an unsuccessful outcome (OR 2.89), and an overhanging or dehiscent facial nerve was found in the second ear in 23% of those who had one in the first, against 2.5% of those who did not. In 394 bilateral stapedotomies analysed with the Glasgow Benefit Plot (Kisilevsky et al.), air-conduction gain was larger after the first operation; 72% of patients moved to the unilateral-loss category after it, and 64% to normal, symmetrical hearing after the second. In 20 patients tested with free-field speech in noise, mean discrimination gain was 19.3% after second-ear surgery against 11.5% in unilateral otosclerosis (De Seta et al.). Prevalence figures need care: the 76% from the Minnesota collection includes histological otosclerosis without stapes fixation, and the 78% CT figure comes from imaged patients at a referral centre.
Family and inheritance
Otosclerosis often runs in families. Estimates vary between studies, but a recent genetic review puts the familial form at about half of patients. Inheritance is often incomplete: a parent may have had a mild, unrecognised loss, and many people have no known affected relative. Several genes have been linked to the condition, and there is no genetic test in routine clinical use. For a relative who notices hearing difficulty, the useful first step is an ordinary hearing test.
Sources
- Hueb MM, Goycoolea MV, Paparella MM, Oliveira JA. Otosclerosis: the University of Minnesota temporal bone collection. Otolaryngol Head Neck Surg. 1991;105(3):396-405. PubMed
- Walker BA, Thorwarth RM, Stull LL, et al. Incidence of concomitant semicircular canal dehiscence with otosclerosis. Otol Neurotol Open. 2022;2(2):e012. PubMed
- Kisilevsky VE, Bailie NA, Dutt SN, Halik JJ. Functional results of 394 bilateral stapedotomies evaluated with the Glasgow Benefit Plot. Eur Arch Otorhinolaryngol. 2010;267(7):1027-34. PubMed
- Shine NP, Rodrigues S, Miller S, Packer P. Bilateral stapedectomy: association between first- and second-ear surgical findings and their effects on the second-ear outcome. Ann Otol Rhinol Laryngol. 2008;117(3):207-11. PubMed
- Gristwood RE, Bedson J. Observations on bilateral symmetry of the stapedial footplate lesion and narrowing of the oval window niche in otosclerosis. Ann Otol Rhinol Laryngol. 2008;117(8):569-73. PubMed
- De Seta E, Rispoli G, Balsamo G, et al. Indication for surgery in otosclerotic patients with unilateral hearing loss. Otol Neurotol. 2009;30(8):1116-21. PubMed
- Curatoli L, Pontillo V, Ralli M, et al. Unilateral versus bilateral stapes surgery: a comparative study on auditory outcome and quality of life. J Otol. 2024;19(2):91-96. PubMed
- Tavernier LJM, Fransen E, Valgaeren H, Van Camp G. Genetics of otosclerosis: finally catching up with other complex traits? Hum Genet. 2022;141(3-4):939-950. PubMed
Common questions
Does otosclerosis usually affect both ears?
Yes, in most people. Studies find the disease in both ears in about three-quarters of those affected, though rarely to the same degree. One ear usually loses hearing first and further. The other may follow years later, or may keep hearing normally because its stapes never becomes fixed. The state of the second ear is one of the main factors in any decision about the first.
Which ear is operated on first in bilateral otosclerosis?
Normally the worse-hearing ear, provided its inner ear is healthy enough to benefit. It has more to gain, and if the small risk of inner-ear damage were to occur, the better ear would still be there to rely on. Operating the better ear first would put the hearing you depend on most at risk, for a smaller gain.
How long should I wait before the second ear is operated?
Most surgeons wait at least six months, and often a year, until the result of the first ear is stable: the air-bone gap closed, bone conduction unchanged, dizziness gone, and your own experience of the operated ear clear. There is no fixed rule and practice varies between surgeons. Follow the advice given for your own case.
Is stapedotomy on the second ear riskier than on the first?
Published series have not shown a clearly higher risk in the second ear. The risks are of the same kind: temporary dizziness and taste change, tinnitus, and severe inner-ear loss in roughly 0.5–1%. But two operations mean two exposures to that risk, and difficulties found in the first ear, such as a very thick footplate, tend to recur in the second.
Is it worth operating the second ear if the first now hears well?
It can be. With two working ears the brain locates sound and follows speech in noise better than with one, and in a large series about two-thirds of people reached normal, symmetrical hearing after the second operation. But some people are content with one good ear, and a hearing aid in the other is a sound alternative. It is a choice, not a necessity.
Can I have surgery on one ear and a hearing aid in the other?
Yes, and many people do. Because the inner ear is usually healthy in otosclerosis, a hearing aid works well, and it brings the second ear back into two-eared hearing without surgical risk. The aid can be kept for good, or surgery on that ear can be considered later; the result of surgery does not depend on it being done early.
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.