Vincent Cumberworth BSc FRCS Consultant Ear, Nose and Throat Surgeon
Clementine Churchill Hospital Sudbury Hill Harrow Middlesex HA1 3RX
Private Secretary: Tel: 020 8872 3866 Fax: 0208872 3861

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Cholesteatoma and Mastoid Surgery

There are 3 layers to the eardrum; an inner mucosal, middle fibrous (which gives the drum strength) and the outer is squamous (skin).  Cells are shed from the surface of the skin and move radially across the edge of the drum to the annulus (the strong, fibrous, margin of the drum) and then laterally along the skin of the ear canal, becoming part of “wax”.  It is possible for a pocket of skin to grow inwards from the drum and, if this is in the form of a “cave with a narrow neck”, this can erode inwards.  If left untreated in the long-term this can gradually become larger and also be associated with some bone erosion, due to enzymes secreted by the mass of cholesteatoma.  This disease may involve the ossicles of the middle ear, causing hearing loss.  The erosion is a very slow process but, in the longer term, complications can include meningitis, extradural, subdural and intracerebral abscess, facial palsy, dead ear, dizziness and pressure effects on the brain (hydrocephalus).  The risk of these complications is small but, overall, the safer option in the longer term is generally to consider surgery to “exteriorise” and remove the disease.  This operation is termed a mastoid exploration.

The precise nature of the mastoid exploration can vary from case to case, depending on the amount of bone which needs to be removed.  This area of disease can erode posteriorly into the “honeycomb” of cellular bone just behind the ear, in the mastoid process, and can also erode the ossicles or bones of the middle ear.  The aim of surgery is to remove the disease and prevent long-term complications; this certainly means that hearing is likely to be worse after the operation.  Occasionally it is possible for the hearing to be reconstructed, sometimes in a future operation, but the principle aim is to remove the disease.  Neither can a dry ear be guaranteed; sometimes the ear can discharge after the operation still although local treatment measures can help with this.  The chance of achieving a dry and “self-cleaning” ear is over 80%, although rates vary from case to case.  The hearing is often worse after surgery, at least initially, as the goal is to eradicate and “exteriorise” disease, although later (second or even third stage) reconstruction may be possible.

The operation is performed under general anaesthesia.  The skin approach used in the operation can vary; this may be done by an incision just in front of the ear, an endaural approach, or an incision behind the ear, a postaural approach, and the choice of approach will depend on individual cases, the preference of the surgeon and extent of the disease.  In a very small proportion of cases the removal may be carried out through the ear canal, “a trans-canal” approach.

In the case of very extensive cholesteatoma, the disease may have eroded through the bony wall which separates the middle ear from the mastoid.  This can require more radical surgery, removing the bone separating the middle ear from the mastoid and such surgery would result in an “open cavity”, requiring long-term out-patient follow up.  Typically, this is required every few months, with periodic suction clearance, although frequently a “dry ear” results which is “self cleaning”.

In the case of smaller cholesteatomas, more limited surgery may be performed and – in some cases – planned staged procedures are undertaken.  In this case the bony wall between middle ear and mastoid may be preserved and this permits an “intact canal wall” and prevents problems associating with an open mastoid cavity.  There is a greater chance of maintaining reasonable hearing, reconstructing the ossicular chain and avoiding a potentially discharging mastoid cavity.  Furthermore, an intact wall can permit water into the ear and lessen both problems with swimming and need for “water precautions”.

A potential disadvantage of intact canal wall surgery is that the rate of recurrent and residual cholesteatoma is higher and this can sometimes necessitate a planned second stage procedure, typically around 12 months after the primary procedure.  In the event of the second stage procedure revealing recurrent disease, then further surgery may be required, with a further planned third stage in the event of the canal wall being left intact, although it may be necessary to convert the ear to an open “cavity”.  CT scans (high resolution) are very useful to minimise surgery and to assess any potential recurrence.  MRI, particularly diffusion weighted scanning, can also assist in assessing recurrence of mucosal or squamous disease in the mastoid cavity or behind an intact tympanic membrane.  Squamous disease is typically cholesteatoma; mucosal disease can be actually harder to fully eradicate and can be associated with a persistently discharging ear.

Typically, 10% – 20% of cholesteatomas can recur and in children recurrence rates may be higher, although typically maximal efforts are made to retain an intact canal wall in a child, which in itself can tend towards higher recurrence rates with a higher number of staged procedures.

Temporalis fascia may be harvested to assist healing of the cavity and to help to seal any surgical deficits.  This aspect of the operation is similar to a myringoplasty, referred to above when describing surgery to repair the tympanic membrane.

At the end of the operation there will be sutures and a head bandage is likely to need to be worn for 24 hours post-operatively.  Occasionally there is a drain and there will be a dressing left in the ear which may need to be left there for up to 3 weeks.  Typically, this operation requires a post-operative stay of 1 – 2 days.

There are possible complications from tympanomastoid surgery and the most significant of these involves a risk of around 1 – 3 % of facial palsy, i.e. weakness of the movement of the face, due to damage of the facial nerve during the operation.  Sometimes the disease itself can envelop the nerve and, indeed, facial palsy can be a complication of an untreated case.

It is possible to get a little unsteadiness, or vertigo, and tinnitus (a ringing noise in the ear) after the procedure, which usually settles soon.

There are smaller risks of losing the hearing completely, particularly if the disease has eroded the bone covering the vestibular structures so that during the removal of the disease inner ear components are exposed.

The chorda tympani is a nerve which supplies taste and sensation to the lateral border of the tongue but in many cases this has already been damaged by disease anyway.  If not, then it is possible that post-operatively a slight metallic taste may be noted along the side of the tongue; this usually settles but may be permanent.

Typically 1 – 2 weeks absence from work or school would be recommended following the procedure; it will be around 3 weeks before the dressing is removed and sometimes a further dressing may be inserted  to optimise healing of  the cavity.

In a small proportion of cases, further surgery can be required.  This may be due to recurrence of disease but can also be required for minor adjustments to the cavity to promote aeration and to keep the cavity dry.  Sometimes a planned second (or even third) operation may be undertaken to optimise the outcome and staged procedures may be planned to attempt to minimise the extent of surgery overall.

The ear should be kept dry after surgery, although hair washing may be possible after 7 to 10 days with care, sometimes aided by placing a cup over the ear during rinsing!   Swimming should be avoided for at least six weeks, with specific advice from the surgeon being followed.  It is essential for the ear and cavity to have every chance of healing fully.  Flying is generally also best avoided for around six weeks, especially is any attempt at surgical reconstruction of the ossicular chain has been attempted.