A Discussion of Exostoses (Surfer’s Ear)

Dr Nirmal Patel
MBBS (Hons) FRACS (OHNS) MS (UNSW)

Norwest ENT Group (Director of Otology/ Neurotology)
North Shore Skull Base Institute

HEARING MECHANISM

In order to understand exostoses, one must have some knowledge of the hearing mechanism.

The External Ear
The external ear consists of the auricle and the external ear canal. These structures collect the sound waves and transmit them to the eardrum.

The Middle Ear
The middle ear lies between the eardrum and the inner ear. This chamber contains three bones of hearing: the malleus (hammer), the incus (anvil) and the stapes (stirrup). Vibrations of the eardrum are transmitted across the middle ear space by these three small ear bones. Movement of the third bone (stapes or stirrup) results in fluid waves in the inner ear.

The middle ear chamber is lined by a membrane similar to the lining of the nose and contains secreting glands and blood vessels. This chamber is connected to the back of the nose by a narrow tube called the Eustachian tube.

The Eustachian tube serves to maintain equalisation pressure between the middle ear chamber and the outside atmosphere, as evidenced by the popping sensation noted in the ear during altitude changes.

The Inner Ear
The inner ear is enclosed in dense bone and contains fluids and the tiny hearing cells. The inner ear is lined by a delicate transparent membrane supplied by microscopic blood vessels, in this small chamber fluid waves resulting from movement of the stapes are transformed into electrical impulses in the nerve.

TYPES OF HEARING IMPAIRMENT

The external and middle ear conduct and transform sound; the inner ear receives it. When there is a problem in the external or middle ear, a conductive hearing impairment occurs. When a problem occurs in the inner ear, a sensorineural or nerve hearing impairment is the result. Difficulty in both conduction and sensorineural hearing results in a mixed impairment.

WHAT ARE EXOSTOSES (SURFER’S EAR)

Exostoses are benign bony growths of the external ear canal. Cold water stimulates the bone lining in the external ear canal to grow abnormally. With continued bony growth water is easily trapped between the bony growths and the ear drum causing blockage and infection in the ear. The hearing loss with this external ear canal problem is a conduction hearing loss.

The Normal Ear Drum:

Note the clear view of the whole ear drum.

Exostoses (Surfer’s Ear):

Note how the bony growths are obscuring a view of the ear drum.

MEDICAL TREATMENT FOR EXOSTOSES

With water trapping the use of ear drops such as “aqua ear” will evaporate the water and minimise ear infections. When ear infections occur they usually require antibiotic ear drops and occasionally antibiotic tablets.

SURGICAL TREATMENT FOR CHRONIC EAR DISEASE

When the patient has recurrent ear infections or blockage they become a candidate for surgery called exostectomy (canalplasty).

EXOSTECTOMY (CANALPLASTY)

Surgery to remove the bony growths is performed under a general anaesthetic and involves an incision behind the ear in the hair line. The bony growths are drilled away and this usually takes between 1 to 3 hours. The patient usually goes home the same day and spends 3 to 5 days off work."

WHAT TO EXPECT FOLLOWING SURGERY

There are some symptoms which may follow any ear operation:

Blocked Ear
The ear canal will be packed with plastic and gelatin sponge which is soaked with antibiotics. The packing stays for 4 to 6 weeks and the ear feels blocked for that time.

Tinnitus
Tinnitus (head noise) frequently present before surgery is almost always present temporarily after surgery. It may persist for one to two months and then decease in proportion to the hearing improvement. Should the hearing be unimproved or worse, the tinnitus may persist or be worse.

Numbness of Ear
Temporary loss of skin sensation in and about the ear is common following surgery. This numbness may involve the entire outer ear and may last for up to one year.

Jaw Symptoms
The jaw joint is in intimate contact with the ear canal. Some soreness or stiffness in jaw movement is very common after ear surgery. It usually subsides within one to two months.

Ear Pain
Ear pain when you chew or move your neck , following any chronic ear surgery is expected for 7 days. Pain killing medication controls the discomfort. When the ear is healing itching in the canal is common and as the nerve fibres regenerate around the ear, sharp shooting pains lasting for a few seconds are common.

RISKS AND COMPLICATIONS OF SURGERY

Fortunately, major complications are rare following surgery for correction of exostoses.

Scar Tissue
Scarring of the external ear canal skin after the surgery is the most troublesome complication. The raw skin surfaces covering the raw bone sometimes cause scarring in the ear canal that requires revision surgery in a small number of patients.

Ear Infection
Ear infection with drainage, swelling and pain may persist following surgery or, on rare occasions, may develop following surgery due to poor healing of the ear tissue. Where this is the case, additional surgery might be necessary to control the infection.

Facial Paralysis
The facial nerve travels through the ear bone in close association with the middle ear bones, ear drum and the mastoid. A very rare post-operative complication of ear surgery is temporary paralysis of one side of the face. This may occur as the result of an abnormality or a swelling of the nerve and usually subsides spontaneously.

Haematoma
A haematoma (collection of blood under the skin) develops in a very small percentage of cases, prolonging hospitalisation and healing. Re-operation to remove the clot may be necessary if this complication occurs.

TRAVEL RESTRICTIONS FOLLOWING SURGERY

You should have someone drive you to and from the hospital. Air travel is permissible 48 hours after surgery.

GENERAL COMMENTS

If you do not have surgery performed at this time, it is advisable to have annual examinations especially if the ear is draining. Should you develop dull pain in or about the ear, increased discharge you should immediately consult your Doctor. Should you have any questions in regard to your ear problem, please do not hesitate to contact us at the Norwest ENT Group.

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