Functional Cholesteatoma Surgery


Why cholesteatoma is removed more effectively when a laser is used and how lasers help preserve hearing in cholesteatoma more effectively than any other technique.

John Hamilton's approach to preserving hearing in cholesteatoma surgery


What is cholesteatoma?

In most cases, cholesteatoma results from abnormal growth of the skin of the ear drum into the skull.

The resulting sac continually generates skin cells. These stagnate causing relentless or recurrent ear discharge. The inflammation caused by the infected skin causes erosion of the structures within the skull.

What is cholesteatoma?


Where does cholesteatoma occur?

Cholesteatoma is the accumulation of skin debris within the middle ear.

The middle ear occupies much of the temporal bone which is the main bone on each side of the base of the skull.

Cholesteatoma does not occur anywhere else.


What are the consequences of cholesteatoma?

In addition to ear discharge a patient with cholesteatoma may notice symptoms caused by destruction of the structures within the skull. The commonest of these symptoms is hearing loss.

Less common symptoms include dizzyness, tinnitus and facial weakness. Most people are surprised to learn that cholesteatoma rarely causes pain.

If an abscess forms, it causes pain and swelling around the ear and can result in meningitis or other infection of the brain. When cholesteatoma is neglected such serious complications can cause death.


How does cholesteatoma behave?

Cholesteatoma causes inflammation. Inflammation causes erosion of bone, so the cholesteatoma progressively enlarges.

It also causes scarring so that the cholesteatoma becomes firmly attached to the structures in the temporal bone.

At any time, the indolent suppuration of the dead skin within the cholesteatoma may erupt into an abscess.


How is cholesteatoma diagnosed?How is cholesteatoma diagnosed?

Other ear disorders, such as ear drum perforation and ear canal infection also cause hearing loss and ear discharge.

The following features should raise suspicion that cholesteatoma is present:

Cholesteatoma is usually diagnosed on careful inspection of the eardrum. This may be obvious or it may be subtle. It often requires the ear to be competely clean, which may require specialist skills and equipment.

On rare occasions, scans are required to diagnose or confirm the presence of cholesteatoma


What structures are in the temporal bone?What structures are in the temporal bone?

Most of the temporal bone is occupied by the air spaces of the middle ear. This air space is neede to allow the ear drum to vibrate and transmit sound.

The ear canal, ear drum and hearing bones are also housed within the temporal bone. Their role is also to transmit sound through to the inner ear.

The inner ear, which has two parts, the cochlea (for hearing) and the vestibule (for balance) lies deep within the temporal bone.

Nerves from the brain to the face and neck run through the temporal bone.

Major bood vessels to and from the brain also run through the temporal bone.


What is the treatment for cholesteatoma?

Cholesteatoma is an abnormal physical structure. It cannot be removed with medicines.

As it is progressive, it requires removal, which means surgery.

All cholesteatoma should be surgically removed if the patient is fit enough for anaesthetic.


What are the aims of cholesteatoma surgery?

Cholesteatoma surgery has two conflicting aims. Getting the balance between these is very difficult. This is the reason why you should consider carefully who performs your cholesteatoma surgery.

The conflicting aims of cholesteatoma surgery are:

The conflict arises because:

There are many techniques currently used to try to achieve these aims. Older techniques tend to be heavily biased towards achieving the first aim at the cost of the second.

This is the reason why you should consider carefully who performs your cholesteatoma surgery.


Is it possible to measure how well cholesteatoma surgery is performed?

Mr Hamilton has proposed that four outcomes should be recorded to measure the effectiveness of cholesteatoma surgery.

  1. Complete removal of cholesteatoma
  2. No new growth of cholesteatoma
  3. Dry ear, even when washing or swimming
  4. Socially useful hearing

The first two assess whether the disease has been completely removed. The latter pair assess whether the ear is functioning normally. Each is a simple yes/no answer.


How effective is conventional surgery at removing cholesteatoma?

Take a look at how well cholesteatoma is completely removed in one operation:

Is this necessarily a measure of individual failure? If even the most skilled surgeons leave this amount of disease, the problem resides more with the limitations imposed by the surgical instruments than with the dexterity of the surgeons:


What advances may improve the situation?

Lasers vaporise disease and therefore are:

Some lasers can be transmitted along fibres. These can guide the laser energy around corners. In cholesteatoma surgery, this means that the laser can be guided around the many obstacles in the temporal bone.

Some surgeons feel that endoscopes may help by improving inspection and image capture of cholesteatoma in regions of complex anatomy. However, the benefit of endoscopy in cholesteatoma surgery is limited as:

problems encountered during cholesteatoma surgery conventional steel instruments fibre-guided laser
cochlea damaged by movement of hearing bones movement needed to remove disease no movement involved in disease
many obstacles can work around corners with angled instruments can be guided around corners by optical fibre or off mirror
inflamed tissues full of blood
vessels
dissection worsens bleeding laser stops bleeding
complex anatomy requires dexterity especially around corners point and shoot
The table allows you to evaluate how well suited to the problems posed by cholesteatoma are conventional instruments and the fibre-guided laser; black text indicates disadvantage. blue text indicates benefit


How much does the laser improve the removal of cholesteatoma?

Mr Hamilton compared the complete clearance of cholesteatoma in two hospitals, one with a laser and one without. He did this by checking whether there was any residual cholesteatoma at a second operation.

The flow chart shows how patients were involved in the study:

How much does the laser improve the removal of cholesteatoma?

When Mr Hamilton relied on conventional instruments, he failed to clear the disease completely at the same rate as other good surgeons. When he used the laser as well, the rate at which he failed to clear the disease completely was reduced by a whole order of magnitude.

Effect of laser on usefulness of hearing after cholesteatoma surgery


Does the laser improve hearing results after cholesteatoma?

The laser does not require movement to remove cholesteatoma. This means that an entirely new approach can be adopted to the treatment of firmly adherent cholesteatoma on the hearing bones.

Previously it was necessary to remove the hearing bones with the cholesteatoma, in order to protect the delicate inner ear from damage.

Now the laser can remove firmly adherent cholesteatoma from the hearing bones without movement and thereby without placing the inner ear at risk


How is cholesteatoma removed from the hearing bones?

Cholesteatoma can be lasered from the ossicles themselves without movement.

The ossicles also present a barrier to removal of cholesteatoma.

A special view, the "orthogonal" view, has been developed to get to the cholesteatoma on the other side of the ossicles: this enables a direct view of the deep side of the ossicles, the facial nerve and the gap in between which Mr Hamilton has termed the epitympanic gutter. This view protects the facial nerve and the hearing bones as the cholesteatoma is removed.

Hearing Bone The Epitympanic Gutter Orthogonal View


How is cholesteatoma removed from the epitympanic gutter?


Effect of laser on rate of complete removal of cholesteatoma How much does the laser improve hearing after cholesteatoma surgery?

Mr Hamilton compared the hearing of two groups of patients after cholesteatoma surgery. One group had conventional treatment of the hearing bones, with reconstruction after removal of bones to facilitate surgery. The other group had new, laser-assisted "functional" surgery, in which cholesteatoma was removed from and around the hearing bones, which were left in place.

Analysis of the results showed that the risk of poor hearing in the conventional group was approximately 3 times higher than the risk of poor hearing in the laser group.




Summary

Lasers are better suited to the removal of cholesteatoma than conventional instruments.

Over the last decade Mr Hamilton has provided evidence that:

To achieve these outcomes has required the development of a new approach to cholesteatoma surgery.

This has required new technical terms and ultimately a new operation, Functional Orthogonal Cholesteatoma Surgery.


Futher reading

PDF Please click here to download a pdf file
discussing the evidence for the use of the laser in cholesteatoma surgery in more detail.