In order to understand the basics of ear surgery, a basic knowledge of the structure of the ear (anatomy) and how it works (physiology) is necessary.
The ear is divided into three parts, the outer (external) ear, the middle ear and the inner ear. The outer ear is the "ear" (pinna) itself and the ear canal. They aid in the transmission of sound to the eardrum (tympanic membrane), which separates the external ear from the middle ear. The middle ear normally is air filled, and contains the ossicles (bones of the middle ear) called the malleus, incus and stapes.
The middle ear connects to the back of the nose via the Eustachian tube, it allows air to pass into the middle ear, and allows secretions from the middle ear to drain into the back of the nose. The ossicles conduct sound from the middle ear to the inner ear. The footplate of the stapes connects with a membrane of the inner ear called the round window. This is the first part of the cochlea, which is the organ that converts sound from a form of pressure wave into an electrical impulse, which travels up the nerve of hearing and ultimately arrives at he cortex of the brain were it is perceived as sound.
Picture1. Normal eardrum.
Myringotomy and grommet insertion.
The term myringotomy implies an incision in the eardrum, in this operation a small cut is made in the eardrum under microscopic control. To allow access to the middle ear. Fluid if present in the middle ear can then be aspirated and if required, a small ventilation tube (V.T.,grommet) is inserted into the tympanic membrane.
This operation is one of the most common reasons for general anaesthesia in children the Western world. It is primarily performed to drain mucous from the middle ear in the treatment of the condition known as glue ear. It may also be performed to break the cycle of recurrent middle ear infections that occur in some children. The grommet ventilates the middle ear, thereby taking over, temporarily, the function of the Eustachian tube, and facilitates the drainage of fluid down a compromised Eustachian tube.
Eardrum with fluid in the middle ear
Postoperative care varies from doctor to doctor, and patient to patient. Generally the procedure and the recovery takes a few hours and the patient is discharged on the day of the operation. Paracetomol is usually sufficient for pain relief and eardrops may be provided. The initial postoperative phase is usually uncomplicated, and parents are usually quite surprised by the rapidity at which their children recover from the procedure. There may be some bleeding, and discharge from the ear in the few days. Any discharge thereafter represents an infective process in the middle ear and needs further treatment. Hearing if compromised pre-operatively should recover reasonably promptly after the surgery.
Usually a follow up visit is scheduled with your surgeon, a few days after the surgery, this to check the position of the ventilation tubes and to answer any questions which may have arisen.
With ventilation tubes in place there is a concern that if water enters the ear canal, it may pass through the tube and into the middle ear, and set up an infective process in this area. This is not an inevitability, and some patients with VT"s swim and shower or bath without protection and never have a problem. It advisable however to take some precautions. Simply this involves the use of earplugs (blue tac, cotton wool and vaseline, silicone ear putty, or custom made plugs) and some form of head cover (swimming cap, ear wrap). Soapy or contaminated water should be particularly avoided. Children with VT's should not be prevented from swimming.
Long term follow up
Grommets inevitably are expelled from the body, by a natural process or in some instances may have to be removed. It is possible that after removal a perforation persists in the tympanic membrane, this may require patching- a process termed myringoplasty.
In some situations children may require a further insertion of grommets, if the Eustachian tube function does not return to normal.
Picture shows a grommet,ventilation tube in position.
Myringoplasty is the medical term given to the operation to repair the perforated eardrum. In essence tissue (fascia) is taken from a nearby muscle and placed under the perforated eardrum. The edges of the perforation are trimmed away, thus stimulating an attempt by the body to repair the eardrum. The fascia then acts as a scaffold encouraging the new growth to traverse the perforation thereby restoring the integrity of the eardrum. This process usually takes approximately two to four weeks from the procedure.
Not infrequently the operation is combined with a canalplasty, an operation whereby the ear canal is widened to facilitate access to the perforation.
Removal of exostoses
Exostoses are bony growths, which we believe occur in response to exposure to a combination of wind and water, hence the lay term surfer's ear (as opposed to swimmers ear, which is an infection of external ear). They are removed by a drilling out the bone whilst preserving the skin of the ear canal as much as possible. After the procedure much care is given to the canal to ensure appropriate healing. Once a patient has had this procedure they should always use earplugs when swimming