Cochlear Implants

What are Cochlear Implants?

Cochlear Implants are electrical devices which process audiosignals and then transmit them across the skin to the cochlear implant which in turn then transmits the decoded auditory signals to the electrodes placed in the cochlea which then stimulate the nerve cells allowing the person to hear.

How are Cochlear Implants able to help a person to hear even though they have nerve deafness?

The hair cells in the scala media are responsible for stimulating the nerve cells which are responsible for hearing. In most persons who suffer from nerve deafness it is because the hair cells are affected. The cochlear implant bypass the hair cells and electrically stimulate the nerve cells also known as the spiral ganglion cells. This then allows a person to hear.

Who will benefit from cochlear implants?

There are 2 sets of patients, those who are Prelingually deaf and Postlingually deaf.
Prelingually deaf persons are children who are deaf without ever having heard sound. They are deaf since birth. They are children who have not acquired speech.
Postlingually deaf persons: are those who have gone deaf after having heard sound and have acquired speech.
Prelingually deaf children should have a cochlear implant inserted at the very earliest. By the age of 2 to 3 years the center in the brain responsible for acquiring speech starts to shrink. Most surgeons think that the cut off age limit for inserting cochlear implants is up to the age of 4 years. Beyond the age of 4 the benefits of cochlear implantation falls dramatically.

Who are candidates ( suitable persons ) for cochlear implants?

Candidates for cochlear implants are persons who have

  • Have profound sensorineural ( nerve) hearing losses in both ears.
  • The cochlear should not be damaged or diseased.
  • The person should be motivated.
  • The brain should be in good condition.
  • The person should not have a contraindication for insertion of a cochlear implant.

How are Prelingually deafened children tested for hearing disabilities?

These children need to undergo the following tests

  • Brainstem evoked response audiometry also known as BERA
  • ASSRT is a variation of BERA to determine residual hearing.
  • Otoacoustic emission audiometry also known as OAE
  • Impedance audiometry
  • High resolution CT scanning of the temporal bones in which the cochlear and hearing apparatus is situated.
  • Magnetic resonance imaging of the brain and the auditory nerve.
  • Psychological evaluation.
  • The parents also need to be counselled about the implications of cochlear implantation.
  • The child must be fitted with hearing aids as soon as hearing losses are detected. It has been found that such children do better when fitted with cochlear implants

Where is the cochlear implant placed?

The cochlear implant is placed in the scala tympani through the round window of the cochlea. The Cochlear implant goes all the way to the apex of the cochlea in order to stimulate all the nerve cells of the spiral ganglion. In this way all the frequencies of hearing are stimulated by the cochlear implant.
The mastoid is usually opened and through an operation termed the posterior tympanotomy the round window membrane of the cochlea is approached.

What are the parts of a cochlear implant?

cochlear implant is the device inserted into the round window and is placed under the skin just behind the ear.
The speech processor is that part of the cochlear implant that takes surrounding sound converts it into an electrical signal, codes it and then transmits it across the skin to the cochlear implant where the electrical signal is decoded and transmitted to the nerve cells in the cochlea.

Cochlear implants in Prelingually deaf children

  • Ideally must be inserted by the age of 2 for maximum benefit.
  • Cochlear implants should be inserted in both ears to get the maximum benefit
  • Both implants can be inserted at the same time through two different operations carried out on both ears.
  • Two weeks after the implant has been inserted the device (cochlear implant) is switched on.
  • The child hears sound for the very first time and may get startled and cry. The child soon gets used to it and then wants the device on as often as possible. This is a very good sign.
  • The loudness of the various frequencies are then adjusted and the child is encouraged to wear it for as long as possible and as often as possible.
  • The child and its parents are called regularly for ‘mapping’. Mapping is nothing but tuning of the device to make sure that each frequency of hearing is adjusted to the child’s comfort levels.
  • Cochlear implants allow the child to develop normally provided the parents follow the guidelines for rehabilitation.

Postlingually deaf candidates

These patients suffer from profound sensorineural hearing loss in both ears.

  • This is confirmed on hearing tests like pure tone audiometry, BERA, OAE and Impedance audiometry
  • They will need high resolution CT scans of the temporal bones and MRI scans of the brain.
  • Psychological evaluation of these patients needs to be done.
  • There is no age limit. Patients of very advanced ages , even in their 90’s are found to benefit tremendously from cochlear implants.

Once it is confirmed that they will benefit from cochlear implants implant surgery can be carried out.
ostlingually deaf patients usually benefit most from these devices. They are able to hear even on the telephone.

Single sided deafness

This type of deafness in which there is profound hearing loss only in one ear can be treated through a variety of devices.
The devices offered for the treatment of this problem are the following:

  • CROS (contralateral routing of signal) hearing aid. This device does not need surgery for insertion.
  • Bone bridge: This works like the CROS hearing Aid but need surgery for insertion.
  • Psychological evaluation of these patients needs to be done.
  • Cochlear implantation.

After a careful and thorough examination the ENT physician can help the patient choose the appropriate device to
suit the persons hearing needs.

Some things you need to know about Cochlear Implants

  • They are implants not transplants.
  • A person is likely to need two cochlear implants in their life time as the first implant may need to be removed and a second new one inserted as technology improves and changes.
  • Technology is changing rapidly. Now auditory stimulation is also included. A hearing aid like device is also inserted in the ear canal to achieve better hearing results.
  • Complications like facial paralysis either permanent or temporary can occur. Leakage of brain fluid from the round window can occur. On rare occasions removal of the cochlear implant may be needed. This is termed explantation.
  • Regular and frequent mapping is mandatory.
  • Cochlear implants need to be inserted in both ears to achieve the best possible result.
  • Most cochlear implant patients can undergo an MRI scan with a magnet strength of 1.5 tesla.
  • Some companies are manufacturing implants that are water proof and can be worn while bathing.
  • There is no age limit for cochlear implantation in persons who are Postlingually deafened.

Ear wax is also known as cerumen. Wax is an essential, normal and necessary body secretion found only in the ear. Ear wax is found in no other part of the body other than the external ear canal.

The functions of wax are the following:

  • It water proofs the ear. The external ear canal has a normal film of wax and this prevents most liquids from remaining in the ear. Since the external ear canal is tilted at an angle any fluids entering the ear will slide out. The external ear canal is tilted at an angle below the horizontal thus allowing it to drain by gravity.
  • The ear wax acts as a mild antimicrobial agent. The ear wax prevents germs and fungi from colonizing the external ear canal. Were it not for the ear wax in our external ears harmful germs and fungi would use our ears to enter our bodies causing serious life threatening illnesses.
  • Ear wax also traps debris and then in a conveyor belt like action evacuates all the debris from the ear.

The external ear canal is the only cul de sac lined by skin in the entire human body. In the adult it is approximately 3.75 cms long. It is divided into two parts. The outer cartilaginous part and the inner bony part. The junction between the two is the most vulnerable. Any injury in this area allows infection to invade the ear and skull base and especially in immunocompromised patients.

Should ear wax be removed?

Ear wax in most people does not need to be removed on a daily basis because of a conveyor belt like mechanism that exists in the external ear canal. In other words the ear cleans itself by this self cleaning conveyor belt mechanism that is present in the external ear. The wax is gradually expelled. Movements of the jaw also help in evacuation of the ear wax. Only when the wax gets stuck (impacted) does it need to be removed.

Who should remove ear wax?

Only a trained doctor with adequate instrumentation removed ear wax.
There should be adequate illumination (light) for the ENT doctor to remove the wax and all the proper instruments.
It can be removed with a Vectis or Irrigated with water with a special ear syringe. Sometimes the ENT doctor may need to use a microscope to help remove the wax.

Why should you never instrument your own ear?

  • You cannot see where your ear drum is. Therefore when you insert an object in your ear you may accidentally injure your own ear drum and may even cause it to get perforated.
  • You may injure the skin that lines your external ear canal. The skin that lines your external ear canal is very delicate and thin. If this is traumatized it can bleed. It can get infected and can cause a severe painful infection. In elderly people, in diabetics and in immunocompromised persons this can lead to a severe life threatening illness known as skull base osteomyelitis.
  • When you insert objects in your own ear you may push back all the debris which was about to be expelled from your ear. This may fall back on to your ear drum causing you to feel that your ear is blocked and thus your hearing will get affected.
  • The cotton can fall off the applicator, or the match stick can break off and remain inside your ear canal thus acting as a source of infection. Therefore you should not instrument your own ear.
  • It is possible to contract infections like tetanus, skull base osteomyelitis, fungal infections and other serious life threatening infections because of self instrumentation of your ears.

In summary ear wax is found in healthy ears. When ear wax is not present it makes the external ear canal vulnerable to infections.
Never instrument your own ears with any object. Do not clean your own ears and do not attempt to clean the ears of others. Only a trained doctor with good equipment should clean ears.
All cotton tips come in boxes with warnings against inserting it in the ear canal.

How do ear aches occur?

  • Ear aches (also known as otalgia) in children can occur following a cold where the cold (infection) enters the middle ear via the eustachian tube. This is known as a middle ear infection (also known as otitis media).
  • Ear aches can also occur because of a buildup of wax. Another cause is if a person instruments the child’s ear. This may push the wax onto the ear drum causing pain.
  • An infection of the external ear caused by scratching or insertion of an object can result in otalgia.

What should you do?

If the ear is being instrumented that should stop immediately. Consult your ENT doctor immediately. Medicine to relieve pain can be given. Medicine such as paracetamol relieves pain effectively. Nasal decongestants can also be given.

How is Otitis media treated?

Otitis media is usually caused by a cold entering the middle ear via the Eustachian tube. The child will simultaneously present with a respiratory infection. The ENT doctor will carefully examine the ears, nose and throat of the child.

The commonest bacteria (germs) that cause respiratory tract infections and otitis media are streptococcal bacteria. Staphylococcal bacteria and others may also be found. Often two or more bacteria can be present causing both the upper respiratory tract infection and otitis media.

if the infection is mild and has just manifested itself, oral antibiotics will be given. The kind of antibiotic will be based on (a) Type of bacteria suspected to have caused the infection. (b) Dosage of the antibiotic will depend on the child’s body weight and severity of infection. (c) The duration for which the antibiotic will be given will depend on how quickly the infection responds to the medication. Symptomatic treatment can also be given simultaneously. This medication is given to bring down fever, pain (otalgia) and congestion of the nasal cavity.
Parents, doctors and caregivers need to observe the child’s response to determine if the child is responding adequately to the medication.

Look for antibiotic reactions like a rash, diarrhea, vomiting. Check the child’s temperature. If the child is still listless, still complaining of pain and running a temperature then this means that the child is not responding well to the medication. If this is so then the child will likely need hospitalization.

Can Otitis media cause serious complications?

Yes it can.
It can result in septicemia. This is a condition where the body is not able to contain and resist the infection despite adequate medications and antibiotics being given.

The child will need to be admitted to hospital. Intravenous antibiotics will need to be given. The choice of antibiotic will depend on the bacteria causing the infection. This will be based on a swab taken to identify the bacteria. The swab will be taken from the nose and / or throat.

If the ear drum is red and swollen the doctor might decide on performing a myringotomy. This is a surgical procedure where the surgeon takes a cut (an incision) on the ear drum. This reduces the pressure buildup of pus in the middle ear. The surgeon can aspirate this pus and send it for examination to identify the bacteria causing the infection. The myringotomy goes a long way to reducing pain and pressure in the ear. The myringotomy is performed in the operating room under anesthesia and the surgeon will use an operating microscope to perform the procedure.

On occasion the ear drum ruptures spontaneously and the pus will discharge out in the external ear. Very often the perforation is tiny and heals spontaneously.

On occasion it can be a large perforation which may require surgery at a later date when the infection has been treated. Aggressive treatment with the appropriate antibiotic needs to be given along with other medications to reduce other symptoms like pain.
Ear drops need not be given as the problem lies in the middle ear and not in the external ear.

Can Otitis media cause deafness?

Yes it can.
It can cause temporary deafness or permanent irreversible, profound, sensorineural hearing loss. Therefore each attack of otitis media needs to be treated appropriately and thoroughly.

  • Otalgia (ear pain).
  • Fullness in the ear which results in the child tugging at the ear.
  • Diminished hearing.
  • Fever.
  • Feeling of pressure in the ear.

Should a hearing test be done?

Yes it should be done. This will include a test for hearing as well as to measure the pressure in the middle ear. The hearing tests should be done before and after treatment. However if the child is very ill it may not be possible to perform a hearing test immediately and can be deferred until the child is better.

What are the complications of Otitis media? The complications can be quite serious.

  • Intracranial complications like

    a. Meningitis.
    b. Sigmoid sinus and venous sinus thrombosis.
    c. Brain abscess.

  • Diminished hearing.

    a. deafness.
    b. facial nerve paralysis.
    c. Perforations of the ear drum.

Other causes of ear ache

  • Furuncle (commonly know as a ‘boil’). This is caused by insertion of objects or fingers in the external ear canal. The ear canal will be swollen and painful.
    Treatment consists of giving appropriate antibiotics, pain relievers and ear drops. On occasion the surgeon may need to incise and drain the furuncle.
  • Fungal infections are caused by the insertion of objects in the ear.
    These fungal are superficial and are usually not invasive. Thus they respond to the administration of antifungal ear drops. Suctioning of the debris in the ear and removal of the fungus helps in getting rid of the fungus.
  • Impacted wax: This needs to be removed gently without traumatizing the ear. A wax softener may need to be given first. After suitably applying the drops the wax can then be removed at a later date.

Hearing is the first sense to develop. The growing and developing fetus in the mother’s womb has been found to respond to sounds, especially its mother’s voice. The fetus moves in response to sounds from the outside. It is joyful and happy when the sounds outside are happy and the growing fetus gets stressed out if the sounds are angry, sudden and violent.

The doctor will take a detailed history of the mother’s pregnancy noting if there were any problems during pregnancy such as if the mother had measles, rubella, mumps etc. These illnesses can most likely have a negative impact of the fetus’s hearing.
When the baby is born it is very important to know if the new born can hear well. Since the new born baby is unable to speak it is important to use methods that are reliable, verifiable and accurate to identify if the baby can hear or not.

The first basic and simplest test is the startle reflex. If the new born does not get startled if there is a sudden noise then it is likely that the child may have a hearing impediment.
The ENT doctor will examine the child’s ear to check if there are any obvious problems. It is unlikely that the newborn will have impacted wax in its ears. But whatever debris is there in the external canal is removed.

The newborn can undergo a test known as "Otoacoustic emission (OAE)” audiometry. This is an objective test that is reliable and can be repeated. This test can be conducted at the newborns bedside and is painless. The test takes a few minutes. This tests the hair cells of the cochlea that is found in the inner ear. This test requires the child to be still (and not crying) and that the room should be quiet. If the child fails the test the test should be repeated again the next day. Failing the test could also be the result of amniotic fluid still residing in the child’s external ear.

Brainstem Evoked Response Audiometry (BERA) Also Known as ABR – Auditory Brainstem Response Audiometry.

This is another computerized hearing test. It tests the integrity of the auditory pathway from the inner ear to the brainstem. This test is an objective test and is painless and takes about 15 minutes to do. It has a 96% accuracy. Both the OAE and the BERA are tests used in all modern hospitals to evaluate a newborn child hearing.

If the Child Gets a Failed Test, Then What Next?

The OAE has an accuracy of 90% while that of the BERA is 96%. Both tests should be done together. If the child fails both the tests then both the tests need to be repeated the next day to check the child’s hearing again. It is possible for the child to have normal hearing at the second test. This is because of vestigial remnants of amniotic fluid in the external ear canal and other variables like the child being restless during the first test, ambient noise in the room that has interfered with the test etc.

Which Test Should be Done, OAE or BERA?

Both tests should be done as they both test different aspects of hearing and the auditory nerve and inner ear. Both are standard, routine tests and can be done in most hospitals.

Impedance (Immitance) Audiometry.

This test is also a subjective test and determines the status of the middle ear cavity. Sometimes fluid can be trapped in the middle ear cavity. This can impair hearing. This test is painless and is computerized.

The ENT doctor puts together the events of pregnancy, the birth process, clinical examination and the findings of the OAE, BERA and Impedance audiometry before deciding what the course of treatment should be.
All new born infants should undergo OAE and BERA to determine the status of their hearing even if the pregnancy and delivery was safe and uneventful.

What are antibiotics?

The term Antibiotics is a misnomer. They should be actually called antibacterial medication. Since the term antibiotic is widely used, it is now the term that most people use when referring to them.

They are medicines that act against bacteria. They are effective only against bacteria. Those medications that are used against viruses, parasites etc are termed antiviral, antipararsitic medication.

Antibiotics are responsible for saving millions of lives. In the era before antibiotics were discovered millions of people either succumbed to trivial infections that went out of control or were near death and were severely debilitated following an infection.

A simple cold resulted in a life threatening respiratory tract infection which often resulted in death. Penicillin was the first antibiotic to be discovered. It is the product of an fungi. Penicillin is credited with saving many lives during world war two.

How do antibiotics act?

Antibiotics act by damaging the cell wall of the bacteria. They can also impede the DNA repair of bacteria.

How are Antibiotics given?

They can be given orally, intravenously. They can be applied topically as an ointment or cream or available as drops.

How do doctors decide which antibiotic to give?

Doctors usually decide on the choice of antibiotic depending on which part of the body is affected and therefore the likely bacteria that is causing the infection. They will try to retrieve a sample of the pus to identify the bacteria causing the infection. They will send the pus sample for gram staining, special staining if needed and they will also culture the bacteria in order to identify it and the medicines that will kill the bacteria and those medicines to which the bacteria is resisstent.

Until the report arrives ( the gram stain report is given quickly, but the culture report make take some time) each hospital will have its own protocol according to which the protocol will decide which antibiotic can be given under the circumstances.

Why do most antibiotics need to be given for 5 to 7 days?

Most bacteria are killed within the first two doses. However some bacteria can survive and become resistant to the antibiotic. So the antibiotic is given to ensure that almost all the bacteria that are causing the infection are killed.
It must be remembered that there may be two or more bacteria causing the infection. This will necessitate that the course of the antibiotic be given for 7 days.

What is meant by bacteriostatic and bacteriocidal antibiotics?

Bacteriostatic antibiotics paralyze the bacteria allowing the body’s white blood cells to engulf the bacteria and remove them. The bacteria are paralyzed and cannot fight back. This allows the body’s white blood cells to attack them without being neutralized by the bacteria’s defense mechanisms. Bacteriocidal antibiotics kill the bacteria which are then removed by the body’s white blood cells.

How are antibiotics removed from the body?

They are removed from the body via the liver or kidneys. The liver and kidneys can be damaged by the antibiotics and thus each antibiotic has its own profile and its advantages and disadvantages.

Can antibiotics be given during pregnancy?

The first 3 months ( the first trimester) is the most important for the developing fetus and so antibiotics should be avoided as they can damage the developing fetus.
All antibiotics should have the approval of the gynecologist before being taken during pregnancy. Some antibiotics can be given safely in the third trimester. All antibiotics given during pregnancy should be approved by the Gynecologist supervising the persons pregnancy.

Do antibiotics have dangerous side effects?

Yes they can have dangerous side effects. The side effects can be life threatening. All persons should duly report to their physicians if they know that they have an allergy to a particular medication.

Can Antibiotics cause weakness?

They can do so indirectly by causing the appetite to be affected. Usually the weakness that results is the weakness caused by the infection for which the antibiotic was given.

Can antibiotics be given along with other medication?

Yes they can be given. However there are some medication that cannot be given along with antibiotics. It is therefore important to inform the treating doctor of the other medication being taken. Only then can the doctor decide if the antibiotic can be given along with other medication.

Does Vitamin B need to be given along with antibiotics?

Probiotics are found to be much more effective by lessening the chances of a vitamin B deficiency. Probiotics also reduce the chances of diarrhea that can occur when an antibiotic is given.

Is there any such thing as a strong antibiotic?

No there is no such thing as a strong antibiotic. Antibiotics are decided by which generation they belong to, to what family they belong to, the dosage and the duration for which they are given.

Why is there so much resistance by bacteria to antibiotics?

Mutation by bacteria to antibiotics is there natural resistance to fight against the substance that is seeking to destroy them. To ensure that bacterial resistance is low take the antibiotic in exactly the same way that your well trained doctor has prescribed.

Antibiotics save millions of lives all over the world. Each antibiotic is unique and has its own profile of pro’s and con’s. The doctor puts into consideration a whole list of factors before prescribing them. Adhere to these guidelines and very likely you will recover from the infection for which the antibiotic was prescribed. Literature on the antibiotic, its mode of action, safety profile and other information is available in the pack in which the antibiotic is placed is available for scrutiny.

What is Otosclerosis?

It is also known as Otospongiosis. It is a disorder of bone remodeling limited to the enchondral layer of the capsule of the inner ear. This disorder is limited to the temporal bone only.
Bone is in a constant state of flux and is constantly being remodeled. In the inner ear bone remodeling is much slower as compared to that of the bones of the rest of the body. However a trigger is initiated which causes faster bone remodeling to occur in the inner ear.

There are two phases.
Active phase: In this situation the bone becomes soft and spongy and is very vascular.
Inactive phase: The bone becomes sclerotic and hard, resulting in the name “otosclerosis”. The new bone formation prevents the stapes bone from vibrating causing it to get “fixed” and is thus no longer able to transfer (conduct) sound to the inner ear thus resulting in deafness.

What causes otosclerosis?

In recent times measles is thought to be responsible for causing otosclerosis. The person contracts measles which can then later on cause otosclerosis.
Hereditary ( “inherited”) genes are also identified as a cause.
It was thought that fluoride deficiency in water could result in the formation of “otosclerosis”.

How does otosclerosis present?

The person suffering from Otosclerosis will initially suffer from deafness. This is likely to be a conductive deafness. But on occasion it can present as nerve deafness or as a combination of nerve and conductive deafness known as mixed deafness.

The deafness initially manifests itself very gradually around the age of 20 and then gradually progresses. It mostly occurs in both ears simultaneously. Women are commonly affected and the deafness is first noticed after the first pregnancy.
Other symptoms that can occur are tinnitus (a constant humming sound), a feeling of the ear being blocked. Giddiness (vertigo) can also be present.

What are the tests needed to confirm that the patient is suffering from otosclerosis.

Otosclerosis is a clinical diagnosis, that is to say the ENT physician by listening to the patients history, complaints and from a careful examination can then conclude that the patient if suffering from otosclerosis.
There are tests that are typical of otosclerosis. They are

  • Pure tone audiogram: Usually shows a conductive hearing loss with a dip at 2 KHz , known as Carharts notch.
  • Speech audiometry shows very good speech discrimination scores.
  • Impedance (immitance) audiometry shows the following, (a) Low compliance (Termed an As peak), (b) stapedial Reflexes are absent and (c) Normal middle ear pressure.
  • High resolution CT scanning of the temporal bones in recent times are useful especially in the active phase in detecting areas that are affected by otosclerotic foci.

What are the treatment options of Otosclerosis?

  • Hearing Aids: These offer significant benefit and the patient can hear well using these. The advantages are (a) Excellent hearing, (b) no risk of hearing loss that accompanies surgery. Disadvantages: (1) Hearing Aids are expensive, (2) Batteries need to be replaced, (3) Most insurance companies do not pay for hearing aids, (4) External ear infections as the result of the usage of hearing aids.
  • Surgery: This is usually termed stapedectomy. A stapedectomy is an operation whereby the stapes bone is replaced by a prosthesis that replaces the functioning of the stapes bone. The stapes is removed and an opening (termed ‘fenestra”) is made in the oval window. A prosthesis is then placed on the incus and into the new opening (fenestra). The opening is usually sealed by connective tissue or a by a vein graft to prevent leakage of inner ear fluid (known as perilymph) from leaking out.

A well done stapedectomy results in excellent hearing. Complications of stapedectomy are

  • Permanent irreversible hearing loss. This is a real and genuine complication even when performed by a senior and experienced ENT surgeon. It can result even if the surgery has been done flawlessly. Most surgeons give the incidence of permanent nerve hearing loss following stapedectomy as approximately 5% of the time with 95% of the time the surgery resulting in excellent hearing. Permanent irreversible sensorineural hearing loss can occur immediately or gradually over time
  • If the nerve known as the chorda tympani gets cut it can result in loss of taste
  • Facial nerve paralysis. This can be transient (temporary) or very rarely it is permanent.
  • Perilymphatic fistula: This is a feared complication. This occurs when fluid from the inner ear drips out of the inner ear through the opening made in the oval window. Signs typical of perilymphatic fistula are (i) Severe vertigo, (ii) Tinnitus, (iii) Fluctuating hearing loss. Perilymphatic fistula needs to be treated urgently and requires immediate closure.

Lasers in stapedectomy

Lasers have reduced complications but not eradicated them. Lasers make surgery less traumatic and have reduced the need for manual force.

Right Ear - Coronal

Right Ear - Coronal

Left Ear Axial

Left Ear Axial

What is skull base osteomyelitis?

Skull base osteomyelitis is a serious, potentially life threatening disease of the bones of the skull base most notably from the temporal bone.
It has several names. It was known by the name “Malignant External Otitis.” This was a misnomer as it was not a malignant disease. It behaves in a very aggressive manner. Therefore the name was changed to Skull base osteomyelitis. This means that it is an infection of the bones of the skull, notably the temporal bone in which the ear is housed.

How does it occur?

The most important predisposing factor is that the person’s immune system is very weak and is unable to fight off and over come the infection.
The overwhelming majority of persons who suffer from skull base osteomyelitis also suffer from diabetes which is improperly controlled. Diabetes is now considered a major factor towards contributing to making a person’s immune system incompetent. Advanced age is another contributing factor.
HIV infections are becoming now a common cause of skull base osteomyelitis.

How do infections enter the temporal bone in which the ear is housed?

Most infections enter the ear and skull base through the external ear canal. This occurs by cleaning the ear canal with cotton buds, pins, toothpicks etc. This usually occurs at the junction between the cartilaginous and bony part of the external ear canal. An injury at this junction allows the infection to enter the tissues below causing rapid spread of the disease and then involves the bones of the skull base.
Skull base osteomyelitis can also occur following an infection of the middle ear. The infection then spirals out of control.

What germ (bacteria) is responsible for causing this infection?

The germ that is most often responsible for this infection is a germ called “Pseudomonas aeruginosa”.
This is a very tough bacteria and is difficult to eradicate and is resistant to many antibiotics.

What is the chief symptom of the effect of Skull base osteomyelitis?

The chief symptom is pain. The earache is unrelenting, often described as boring, and is always present. It does not go away with pain killers for long and soon returns immediately after the effect of the pain killer wears off.
Once the disease spreads the pain intensity increases and is then accompanied by facial nerve paralysis and paralysis of other nerves.

How does the physician make a diagnosis of skull base osteomyelitis?

This is a clinical diagnosis.

  • The patient is almost always a diabetic whose blood sugar is poorly controlled.
  • The patient is usually in their sixties and above.
  • There is a history of self-instrumenting the ear canal with an object like a cotton bud.
  • A granuloma is often seen in the external ear canal.
  • A CT scan of the temporal bones will demonstrate a moth eaten appearance.
  • A gallium bone scan will demonstrate how active and fulminant the infection is.

What is the treatment of skull base osteomyelitis?

Surgery is contraindicated and should never be performed as it will hasten spread of the disease.
Surgery if at all is limited to biopsy of the granuloma of the external ear canal.

The mainstays of treatment are prolonged administration of antibiotics. This is usually given for a period of two to three months. Usually A ureidopennicillin is given. An Aminoglycoside can also be given.
The antibiotic needs to be given carefully in a hospital setup and the patient needs to be monitored carefully for side effects of the antibiotic. Kidney damage can occur.

Also the patient’s blood sugar needs to be monitored and controlled.
Topical antibiotics in the form of ear drops can be given. The external ear canal should be carefully cleaned to prevent reinfection.
Some physicians also give the patients hyperbaric oxygen.

How does the treating physician know that the infection is coming under control?

Once the pain starts to lessen and go away then that means that the infection is responding to the antibiotics.
The physician also gets a gallium bone scan later on will show if the infection has receded.
However the principal symptom is pain. If that resolves then the infection is resolving too.
The cranial nerves will also get back their normal function and is indicative of the infection resolving.

Can the skull base osteomyelitis infection return?

Yes it can. This is usually the result of incomplete treatment. The treatment needs to be continued and the infection will then likely come under control.

Can it spread to the other ear?

Yes it can.


  • Skull base osteomyelitis is a serious life threatening condition.
  • Pain is the cardinal symptom and most prominent feature.
  • Nearly all patients suffer from diabetes that is improperly controlled.
  • Quite a few patients are in their sixties and beyond.
  • Surgery is contraindicated except for biopsying the granuloma in the external ear canal.
  • Treatment consists of antibiotics given for a prolonged duration of three to four months.
  • Survival is best if there is no cranial nerve involvement.
  • Survival is poorest if there are other problems like kidney failure.