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Treatments

Mastoidectomy

Mastoid surgery opens the bone behind the ear to remove disease, most often cholesteatoma. How much of the ear canal wall is kept shapes what follows: the chance of disease returning, the follow-up, and whether the ear needs care for life.

What the mastoid is

The mastoid is the bone you can feel behind the ear. Inside it is a honeycomb of air cells, lined like the middle ear and connected to it through a narrow passage at the top (the attic and antrum). Middle ear and mastoid form one air-filled system, ventilated by the Eustachian tube.

The neighbours matter: the facial nerve runs through it, the balance canals of the inner ear lie at its inner edge, a large vein runs behind it, and a thin plate of bone separates it from the lining of the brain.

Why it is opened

Mastoidectomy means removing the air cells with a drill under the operating microscope, for three broad reasons:

  • Cholesteatoma, the commonest. A cholesteatoma that has spread from the attic into the mastoid cannot be removed through the ear canal alone.
  • Chronic infection. In chronic middle-ear disease that keeps discharging despite treatment, diseased air cells may need clearing, usually together with a tympanoplasty. Acute mastoiditis that fails to settle is a rarer, more urgent reason.
  • Access, for example for a cochlear implant, when the mastoid itself is healthy.

Three operations with one name

Cortical (simple) mastoidectomy opens the air cells but leaves the ear canal and middle ear untouched. Afterwards the ear looks and behaves normally.

Canal wall up (intact canal wall) removes disease from the mastoid and middle ear while keeping the bony back wall of the ear canal. The healed canal has its normal shape and usually needs no special care. The price: some corners of the middle ear are hard to see, so microscopic remnants are more easily left behind, and a new retraction pocket can form.

Canal wall down (open technique, or modified radical mastoidectomy) lowers that back wall, so that mastoid and ear canal become one skin-lined bowl, open to the outside through a widened ear-canal entrance (a meatoplasty). Disease has fewer places to hide, and regrowth is usually visible in the clinic. The price: a cavity that may need cleaning for life and is more sensitive to water.

Obliteration: filling the space

Obliteration tries to combine both advantages. After removing the disease, the surgeon fills the mastoid, and often the attic, with bone chips or paste, cartilage, a soft-tissue flap or a synthetic material such as bioactive glass, and keeps or rebuilds the canal wall. The result is a normal-sized ear canal, no cavity to look after, and no empty space for a new pocket. Systematic reviews report low rates of disease return and less long-term discharge than with an open cavity. Because the filled area cannot be inspected, follow-up relies on MRI.

Canal wall up or canal wall down?

There is no single right answer, and practice varies between surgeons. The choice weighs the extent of disease (canal-wall erosion, hidden recesses, a fistula into a balance canal); how well the ear is ventilated, since a poorly aerated ear tends to form new pockets; whether reliable follow-up and MRI can be assured; previous surgery; and daily life — swimming, hearing aids, and whether lifelong cavity care is acceptable. It is reasonable to ask which technique is planned, and what might change it during the operation.

What the comparative evidence shows

In adults, a systematic review of seven comparative studies found higher recidivism after canal wall up in six (16.7–61.0%) than after canal wall down (0–13.2%); one showed the reverse. An earlier meta-analysis found a relative risk of 2.87 with an intact canal wall, but similar rates for staged canal wall up versus single-stage canal wall down. A 2025 meta-analysis (84 studies, 12,819 patients) pooled recurrence at 7% after canal wall down and 16% after canal wall up. In children (17 cohorts) the difference was not significant, and the mean air-bone gap was about 7.6 dB smaller after canal wall up. After obliteration, one review reported 4.6% recurrent and 5.4% residual disease; a meta-analysis found canal wall down with obliteration associated with lower recurrence than canal wall up (OR 0.33) and less persistent otorrhoea than an open cavity (OR 0.41). All data are retrospective, with selection bias and varying definitions.

Residual and recurrent disease

Residual disease grows from microscopic cells left behind, usually as a small pearl. Recurrent disease is a new cholesteatoma from a fresh retraction pocket, often years later. Residual disease is more typical after canal wall up; recurrence is more typical in a cavity whose shape traps skin.

Across studies, one or the other is reported in roughly 10–30% of ears — more in children and in extensive disease, less after canal wall down. The figures rise with the length of follow-up, which is why follow-up is counted in years.

Second-look surgery or MRI?

After canal wall up, nobody can see behind the rebuilt drum and canal wall. The traditional answer is a planned second-look operation, typically six to eighteen months later, to remove any residual pearl while it is still small, often rebuilding the hearing at the same time.

Non-echo-planar diffusion-weighted MRI has changed this. Cholesteatoma shows as a bright spot, and meta-analyses report sensitivity and specificity of about 90%. Many centres now rely on a series of scans and reoperate only when a scan shows disease or the hearing needs rebuilding. Pearls under about 3 mm can be missed, so one clear scan is not the end of follow-up. A second look remains reasonable when complete removal is uncertain, when this MRI is unavailable, or when the hearing is to be rebuilt at a second stage.

Diffusion-weighted MRI in practice

Non-EPI (turbo spin-echo) DWI has replaced echo-planar DWI, which suffers from skull-base susceptibility artefact. A meta-analysis of 26 studies (1,152 episodes) with surgical correlation gave pooled sensitivity 0.91 and specificity 0.92, similar in the postoperative subgroup. In children, ten studies gave sensitivity 89% (95% CI 52–99%) and specificity 93%, with limited detection under 3 mm.

Living with a mastoid cavity

An open cavity is lined with skin that does not always clean itself. Most people need it cleaned under the microscope for life — often once or twice a year, more often if it is large or tends to discharge.

  • Water can trigger discharge. Many people keep the ear dry in the shower and swim with a fitted plug, if their surgeon agrees. Diving is generally discouraged.
  • Cold water or wind can cause brief giddiness, because the balance canal lies close to the surface.
  • Hearing aids can be harder to fit; a custom mould or a bone-conduction device sometimes helps.
  • Discharge that keeps returning can often be improved by revision surgery: a wider opening, or obliteration of the cavity.

Hearing

Mastoidectomy is not in itself a hearing operation. Hearing afterwards depends mainly on what the disease has left of the eardrum and ossicles, and on whether the chain is rebuilt, at once or at a second stage (see ossiculoplasty). It may improve, stay the same or worsen — sometimes the cholesteatoma itself was carrying sound across an eroded chain. Keeping the canal wall tends to give somewhat better hearing. A dry ear makes a hearing aid easier to wear. Hearing is judged at three to six months.

Risks

In general terms, because frequencies depend more on the disease than on the operation:

  • Taste change on one side of the tongue. The taste nerve crosses the middle ear and may be stretched or, if surrounded by disease, divided; the change usually fades, or stops being noticed, over weeks to months.
  • Dizziness. Brief unsteadiness is common; the risk is higher when cholesteatoma has eroded a balance canal (see protecting the inner ear).
  • Inner-ear hearing loss and tinnitus: uncommon, and more likely when disease has reached the inner ear.
  • Facial nerve weakness: rare. Disease can strip the nerve’s bony covering; surgeons identify the nerve, and many use nerve monitoring.
  • Wound problems: infection, or numbness around the ear. Rarely, a leak of cerebrospinal fluid or bleeding from the large vein.

Against these stands the risk of leaving cholesteatoma in place: it keeps eroding bone.

Recovery

General ranges; your own surgeon’s advice comes first.

  • Hospital stay: from a day case to one or two nights.
  • Wound and packing: an incision behind the ear heals in one to two weeks; canal packing usually comes out after one to three weeks.
  • Work: often one to two weeks for desk work, longer for physical jobs.
  • Water and pressure: keep the ear dry and avoid nose-blowing until told otherwise. An open cavity often takes a few months to heal fully.
  • Flying: often after four to six weeks; see flying after ear surgery and recovery after ear surgery.

Facial weakness, severe spinning vertigo, a sudden drop in hearing, severe headache with fever or neck stiffness, or a painful red swelling behind the ear need same-day care; discharge that increases or smells needs a call within a day or two. See when to contact your surgeon.

Sources

  • Kerckhoffs KG, Kommer MB, van Strien TH, et al. The disease recurrence rate after the canal wall up or canal wall down technique in adults. Laryngoscope. 2016;126(4):980-987. PubMed
  • Tomlin J, Chang D, McCutcheon B, Harris J. Surgical technique and recurrence in cholesteatoma: a meta-analysis. Audiol Neurootol. 2013;18(3):135-142. PubMed
  • Massoud S, Farhat R, Abd Elhadi U, et al. Incidence rate and determinants of recurrent cholesteatoma following surgical management: a systematic review, subgroup, and meta-regression analysis. Biomedicines. 2025;13(10):2506. PubMed
  • Solis-Pazmino P, Siepmann T, Scheffler P, et al. Canal wall up versus canal wall down mastoidectomy techniques in the pediatric population with cholesteatoma: a systematic review and meta-analysis of comparative studies. Int J Pediatr Otorhinolaryngol. 2023;173:111658. PubMed
  • van der Toom HFE, van der Schroeff MP, Pauw RJ. Single-stage mastoid obliteration in cholesteatoma surgery and recurrent and residual disease rates: a systematic review. JAMA Otolaryngol Head Neck Surg. 2018;144(5):440-446. PubMed
  • Salem J, Bakundukize J, Milinis K, Sharma SD. Mastoid obliteration versus canal wall down or canal wall up mastoidectomy for cholesteatoma: systematic review and meta-analysis. Am J Otolaryngol. 2023;44(2):103751. PubMed
  • Lingam RK, Bassett P. A meta-analysis on the diagnostic performance of non-echoplanar diffusion-weighted imaging in detecting middle ear cholesteatoma: 10 years on. Otol Neurotol. 2017;38(4):521-528. PubMed
  • Bazzi K, Wong E, Jufas N, Patel N. Diffusion-weighted magnetic resonance imaging in the detection of residual and recurrent cholesteatoma in children: a systematic review and meta-analysis. Int J Pediatr Otorhinolaryngol. 2019;118:90-96. PubMed

Common questions

What is the difference between canal wall up and canal wall down mastoidectomy?

Both remove disease from the mastoid bone behind the ear. Canal wall up keeps the bony back wall of the ear canal, so the ear looks normal and needs little care, but leftover disease is more likely and follow-up with MRI or a second operation is needed. Canal wall down removes that wall, creating an open cavity that is easier to check and in which disease returns less often, but which usually needs cleaning for life.

How long does recovery from a mastoidectomy take?

Many people go home the same day or after one or two nights. The wound behind the ear heals in one to two weeks, packing is usually removed after one to three weeks, and desk work is often possible after one to two weeks. An open cavity takes longer, often a few months, to heal fully. Flying is often allowed after four to six weeks. Follow the advice given for your own operation.

Will I need a second operation after cholesteatoma surgery?

Not necessarily. After a canal wall up operation, some surgeons plan a second look six to eighteen months later to check for leftover disease and to rebuild the hearing. Many now use a special MRI scan (non-echo-planar diffusion-weighted imaging) instead, and operate again only if it shows disease or if hearing reconstruction is needed. Either way, follow-up lasts years, because cholesteatoma can return late.

What does caring for a mastoid cavity involve?

An open cavity collects skin debris and wax that it cannot always clear itself. Most people need it cleaned under a microscope at regular intervals, often once or twice a year, for life. Keeping water out helps prevent discharge; some people swim with a fitted plug if their surgeon agrees. Cold water or wind may cause brief dizziness. A cavity that keeps discharging can often be improved by further surgery.

Will a mastoidectomy improve my hearing?

Not by itself. The operation removes disease; hearing depends on the state of the eardrum and the three small bones, and on whether they are rebuilt, at the same operation or later. Hearing may improve, stay the same or become somewhat worse, particularly if the cholesteatoma was bridging a gap in the chain. Where hearing cannot be restored, a hearing aid or bone-conduction device can help.

What are the main risks of mastoid surgery?

A temporary change in taste and brief unsteadiness are the most common. Less often the inner ear is affected, causing hearing loss, tinnitus or dizziness, particularly when disease has already eroded a balance canal. Facial nerve weakness is rare and needs same-day assessment. Wound infection and numbness around the ear can occur. Untreated cholesteatoma slowly erodes bone, which is usually the greater risk.

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.