Infections of the Outer Ear
Treatment is antibiotic ear drops and antibiotics by mouth, and hot compresses also help decrease swelling and pain. If the ear canal is swollen shut, a small wick of fabric will be placed into the canal so that the ear drops will be pulled into the ear canal and just not run back out after application.
Infections of the Middle Ear
The treatment consists of antibiotics and pain medication. Pain may be reduced by holding the child upright in the lap so the fluid in the middle ear tends to stay away from the inside of the ear drum.
If the infections are recurrent or the middle ear retains fluid between bouts of infection, then the child may need to have small metal or plastic ventilating tubes (PE tubes) placed in the ear drum to prevent fluid from accumulating in the middle ear, which provides an environment in which bacteria readily grow. If the child has enlarged adenoids, removal will usually help in the prevention of recurrent infections. Since allergies, particularly to dairy products, often play a role, a trial of soy-based milk should be tried to see if the infections stop recurring.
Tumors of the Ear
Squamous Cell Carcinoma
These malignant tumors can spread to lymph nodes in the neck and other areas and must be surgically removed. When they start in the skin of the ear canal, there are few symptoms, so they are usually detected later in the course of the disease. In these cases, a portion of the temporal bone must be removed to ensure complete removal of the tumor with a normal cuff of tissue around the primary site of the tumor. Usually, radiation therapy is given after surgery to be certain that no cancer cells have been left in the area.
Basal Cell Carcinoma
Simple excision using Moh’s technique -- removing very small amounts of tissue in circles around the tumor and looking at these sections under the microscope while surgery is in progress -- allows complete removal while sparing all normal tissue. Once a cuff of normal tissue is seen under the microscope, it is certain that the entire tumor has been removed. This permits removal of cancerous tissue only and leads to far less damage to normal tissue of the auricle. Usually skin grafts are applied over the excised area and heal nicely with good cosmetic results.
Treatment consists of wide excision of the skin surrounding the tumor at the primary site. If lymph nodes are felt in the neck when the patient is first seen, a neck dissection will be done to remove these nodes. This allows the extent of spread to be determined by looking at the nodes under the microscope to see if they contain tumor cells.
Melanoma, depending on how malignant the cells look in the microscope and the depth of their invasion into the skin, is usually treated with additional therapy consisting of possible radiation, chemotherapy, and more recently, interferon therapy (immune cell based therapy).
Bony exostoses are removed by simply sanding them down. The procedure may be done under local or general anesthesia.
An audiogram or hearing test will show a one-sided nerve type of hearing loss. Usually an auditory brainstem response (ABR) test is done, which measures how long it takes nerve impulses to go from the inner ear to the brain. There will be a delay in conduction time, which is diagnostic for the tumor. An MRI is then performed to show the location and size of the tumor.
These tumors, depending on size, may be removed through the mastoid part of the temporal bone or through an opening in the skull called a craniotomy. If not treated, they continue to grow and produce symptoms of a brain tumor and can result in death, so most are surgically removed unless the patient is of advanced age or has other serious medical problems that make surgery too great of a risk.
Rarely, a benign tumor of the cells around the jugular vein, where it passes through the middle ear, may occur. These are called glomus tympanicum tumors and may be noticed by the patient because of a persistent sound of their pulse in the involved ear. These tumors are removed through both the middle ear and the mastoid bone using microscopic technique.
Hearing Loss and Deafness
Conductive Hearing Loss
Virtually all of the conditions of conductive hearing loss are curable using modern microsurgical procedures to re-establish the connection from the environment to the footplate of the stapes bone. Using modern diagnostic audiometry (hearing tests), along with imaging techniques such as CT scans and MRI’s of the temporal bone, the site of the interruption of the conduction of sound wave energy to the inner ear may be established before surgery. Almost all causes of conductive hearing loss can be cured and normal hearing restored using the operating microscope with very small surgical instruments, usually with an outpatient operative procedure.
Sensorineural Hearing Loss
All sensorineural hearing losses may be treated with hearing aids or rarely a cochlear implant. Hearing aids are prescribed by an otologist and are fitted by a licensed audiologist for the patient and come in a variety of types, shapes and sizes. Many specifically amplify particular sound frequencies. These are matched to the frequencies in which the patient has the most hearing loss so they more closely match normal hearing. Many have remote controls for volume.
In patients with profound deafness, a cochlear implant may be placed. This device is essentially a microphone that converts sound into electrical impulses. After a portion of the temporal bone called the mastoid is drilled away, small wires corresponding to several sound frequencies are passed into the cochlea (hearing part of the inner ear). As the microphone picks up sound it is converted into an electrical impulse that directly stimulates the fibers of the acoustic nerve where they enter the cochlea from the brainstem, thus bypassing the “hair cells” of the inner ear that normally create the nerve impulses. These devices over the past 50 years have advanced to the point that speech recognition without lip reading is quite good.
Mixed Conductive and Sensorineural Hearing Loss
Mixed hearing loss, although not common, does occur. If the ear is capable of hearing from the standpoint of nerve function at a higher level than the conductive loss, then the cause of the conductive loss is corrected. This is done with the surgical procedure appropriate for the particular type of mixed loss that afflicts the patient. For example, if the patient has disruption of the ossicles, which produces the maximum conductive loss, then the ossicular chain will be reconstructed even though the patient may have a milder sensorineural hearing loss.
Testing for Vertigo
It is possible to test the function of the calcium carbonate crystals and the hair cells by purposely causing head motion. By introducing cold water or air into the ear canal, a convection current of fluid flow in the inner ear may be started, thus moving the crystals and bending the hair cells, signaling to the brain the head has moved. By observing the motion of the eyes during this maneuver and knowing the standard response over many thousands of people, it is possible to tell if the hair cells are not functioning properly.
It is thought that many cases of vertigo are due to these crystals falling from their perch on the cilia. Based on this test called an electronystagmogram or visual nystagmogram, the patient is then put through a series of maneuvers where the head is rapidly moved in a direction that would cause the stones to regain their normal location. The procedure has been found to be quite effective in roughly half of the patients with vertigo.
Another common cause of vertigo is abnormal tension in the muscles of the neck due to disc disease in the vertebral column or arthritis. Many times physical therapy for the neck will improve vertigo.
Vertigo responds to some types of medications, including muscle relaxants and anti-anxiety drugs. The key is that vertigo requires evaluation not only to direct treatment but to be certain it is not a symptom of a more serious underlying disorder in the ear or nervous system.
An otologist examining the tympanic membrane can usually see or feel with a small instrument a pocket at the upper back where the cells have migrated into the mastoid bone. If left untreated, the cholesteatoma will continue to grow and secrete enzymes that dissolve bone, ultimately leading to a connection between the inside of the skull and the middle ear through which bacteria may infect the coverings of the brain or the brain itself.
Cholesteatomas are removed by carefully drilling away the mastoid bone under an operating microscope and removing all of the skin cells from the mastoid leaving a cavity that is exposed directly to the ear canal, so that it may be kept clean and clear of infection. Hearing may often be restored by microsurgical reconstruction of the small bones of the middle ear.
Otosclerosis is readily curable, and normal hearing may be restored by removing the stapes (stapedectomy) and replacing it with a Teflon piston that vibrates the fluid of the oval window. The operation is most often done as an outpatient under general anesthesia.
Tests of Ear Function
The primary test of ear function is checking the ability to hear, which is known as an audiogram. Audiometric testing, or a hearing test, consists of pure tones of different frequencies that can be heard by the human ear being played into headphones in a soundproof booth. The ear not being tested is given an input of white noise to eliminate conduction of sound through the skull bones so that each ear is tested separately. It is very accurate in detecting hearing loss and determining if it is conductive (due to problems with the ear drum or small bones of the middle ear) or sensorineural (due to damage to the nerve cells of the inner ear).
Occasionally, in addition to the audiogram, a list of two-syllable words is read into the headphone to each ear to determine if the person is able to sort out the different frequencies of sound, a process called discrimination. Patients with a mild pure-tone hearing loss may perform poorly on the discrimination portion of the audiogram, which may indicate significant damage to the nerve cells of the inner ear or even a benign tumor of the lining of the nerve from the inner ear to the brainstem (acoustic or vestibulocochlear neuroma).
The evaluation of the ear usually includes a test called a tympanogram, during which air pressure is placed against the ear drum (tympanic membrane) to determine if it moves in and out normally. At the same time, a sound is introduced that causes a reflex of the stapedius muscle, which is a small muscle in the middle ear that functions to dampen the motion of the stapes in response to very loud sounds, thus protecting the inner ear from acoustic damage. If the middle ear is filled with fluid, the tympanic membrane will not move in and out as it should and the tympanogram is said to be flat. If the stapedius muscle does not reflexively contract with the sound, this could be caused by otosclerosis (fixation of the stapes bone) or a tumor on the acoustic nerve.
More sophisticated tests include electrocochleography (EchoG), which can determine which hair cells (the nerve cells with cilia on their surface that send signals to the brain when sound moves the fluid of the inner ear) in the cochlea are damaged and is useful in determining if there has been temporary damage to the hair cells from noise exposure. It also aids in the confirmation of the diagnosis of Meniere’s disease and in cases of leakage of fluid from the inner ear known as a perilymph fistula. However, some of the usefulness of this test has diminished in recent years because it requires placing electrodes next to the cochlea and is painful and difficult to perform.
Auditory Brainstem Response (ABR)
Another important test of inner ear function is the auditory brainstem response (ABR). This allows measurement of the time it takes a sound in a headphone worn by the patient to become a nerve impulse traveling up the vestibulocochlear nerve. A delay in the time for this event indicates that there is pressure on the cochlear nerve, which could indicate a benign tumor on the coverings of the vestibulocochlear nerve called an acoustic neuroma.
Tests of the balance function of the inner ear are based on the fact that when vertigo is present, the eyes reflexively move to restore what is termed “the last field of vision.” Vertigo is induced by starting convection currents in the fluid in the semicircular canals by the introduction of cold water or air into the ear canal. The movement of fluid stimulates the hair cells in the semicircular canals, mimicking what happens when the head is moving. By assessing the response of eye movements, it is often possible to tell which semicircular canal is affected by disease and if physical maneuvers of the head to reposition the calcium carbonate crystals atop the hair cells will improve vertigo.
Although not specifically tests of ear function, a great deal of diagnostic information may be obtained by imaging of the inner ear. Prior to the invention of the CT scan and the MRI, the dense temporal bone made it virtually impossible to see tumors or abnormalities of the inner ear. Plain X-rays, which were the forerunner of CT scans, did enable a partial view of the small bones in the middle ear and the mastoid area behind the inner ear.
The invention of the CT scan revolutionized the diagnosis of ear disorders. The computerized, three dimensional reconstruction of serial X-rays of the dense temporal bone allowed for the first time accurate visualization of the inner ear structures and the nerves connecting them to the brainstem. The additional development of MRI scanning, which is extremely good at rendering pictures of soft tissue structures, further enhanced the diagnosis of abnormalities of the nerves of the inner ear and its structures.
The combination of all of these methods of assessing ear function and visualizing abnormalities of the ear has made the timely and accurate diagnosis of ear disorders a reality. With the combination of tests of function and pictures of this highly complex anatomy, many accurate diagnoses of ear disorders are now available. Combined with the use of the operating microscope, modern ear surgery for infections, hearing loss and tumors is truly minimally invasive.
My family notices that I have a hearing loss. What should I do?
Hearing loss is best evaluated by an otologist (ear specialist). Initially, after a medical history is taken, the ear will be visually examined through a scope inserted in the ear canal (otoscope), as shown in the picture above. This is usually followed by a hearing test or audiogram performed by an audiologist. If needed, other special tests to further evaluate the function of different parts of the ear may be performed. One such test is a tympanogram, which places air pressure against the ear drum (tympanic membrane) to be sure the drum is moving properly. Sometimes, fluid in the middle ear behind the ear drum may be the cause of hearing loss. This test also evaluates the movement of the small bones of the middle ear and indirectly tests one of the reflexes that is lost when a tumor is present on the nerve from the inner ear to the brain.
Another special test done is an auditory brainstem response (ABR), which screens for a benign tumor of the insulation of the nerve trunk from the base of the brain or brainstem to the inner ear (acoustic neuroma). Although these types of tumors are benign, because of their location next to the base of the brain, they may have severe consequences with enlargement, in many ways behaving as a brain tumor.
If abnormalities of the inner ear itself are present, an electrocochleography (measurement of the function of the nerves cells in the cochlea) may be done to evaluate the function of the nerve cells inside the "hearing" part of the inner ear.
If a tumor or other disorder is suspected as the cause of the hearing loss, or there are other physical findings, these tests may be complemented by a CT scan of the temporal bone (a computerized reconstruction of X-rays). At times, an MRI (magnetic resonance imaging) scan may be done to see the vestibulocochlear nerve (acoustic nerve) or nerve conducting the impulses from the inner ear to the brain for the senses of hearing and balance. Treatment may range from fitting a hearing aid to surgery for removal of a tumor of the nerve to the inner ear (acoustic neuroma).