Glossary:

Acoustic neuroma - vestibular schwannoma

Angiogram - a special test that is performed by an experienced radiologist where a plastic tube or catheter is inserted into one of the blood vessels in the groin and is then advanced to the blood vessels in the neck. Using this test multiple tumors can be identified and arterial blood vessels feeding the tumor can be clotted off.

Artery - a vessel which carries richly oxygenated blood from the heart to other organs

Audiogram - a hearing test conducted in a sound-proof room by a qualified audiologist

Auditory brainstem response - a special hearing test done while a patient is hearing clicks or certain tones.

Bilateral - on both sides

Canal wall down procedure - a procedure where the bony partition between the back part of the ear canal and mastoid is removed

Canal wall up procedure - a procedure where the bony partition between the back part of the ear canal and mastoid is kept intact

Central - near the brainstem

Cerebellum - portion of the brain found in the posterior fossa which regulates fine motor coordination

Chorda tympani nerve - a nerve which transmits taste information from the front two-thirds of the tongue back to the brain. The nerve travels through the middle ear close to the ossicles.

Cochlea - part of the inner ear involved in hearing.

Conductive Loss - A type of hearing loss which arises from the middle ear, due to wax, fixation of the ossicles, ear infection etc., and is often easily corrected by medication and/ or surgery.

Congenital cholesteatoma - a cholesteatoma that arises in an ear from squamous epithelium that became entrapped within the middle ear or petrous apex

Conjunctiva - the white part of the eye

Craniotomy - temporary removal of a portion of the skull over the brain.

Craniectomy - permanent removal of a portion of the skull over the brain.

CT scan - a computerized tomography scan or special X-ray which allows

Dura - a tough fibrous layer which is found immediately under the skull which protects the brain.

Electronystagmogram (ENG) - a balance test which involves recording movements of the eyes while changing positions of the head with respect to the earth's gravitational field. The eye movements are also recorded while cool and warm air or water is blown into the ear canal.

Embolization - a procedure done during angiography which involves blocking the blood vessels supplying blood to the tumor

Endolymph - one of two different fluids found in the inner ear

Endolymphatic hydrops - a condition of excessive fluid within the endolymphatic space

Glomus Jugulare - a paraganglioma which arises from paraganglia around the jugular bulb

Glomus tympanicum - a paraganglioma which arises from paraganglia in the middle ear

Hydrocephalus - a buildup of spinal fluid that can lead to brain dysfunction and death

Internal auditory canal - a bony canal which transmits the cochlear, vestibular and facial nerves

Internal Jugular Vein - a vein which collects blood from the brain and empties eventually into the heart

Jugular bulb - a venous cavity which receives blood from the sigmoid sinus and empties into the internal jugular vein.

Keratin - a protein found in cells that form squamous epithelium

Lacrimal glands - glands which produce tears in the eyes

Mastoid - the bone located directly behind the external ear which comunicates with the middle ear

Mastoidectomy - a procedure to remove part of the mastoid in order to clean out infection and remove cholesteatoma

Meniere's disease - endolymphatic hydrops for which no cause can be identified

Middle Fossa approach - a hearing preservation approach which allows visualization of the roof of the internal auditory canal for removal of small tumors. This approach involves a craniotomy above the ear with retraction of the temporal lobe of the brain.

Mixed Loss - A type of hearing loss caused by a problem with both the middle and inner ear/nerve simultaneously.

Modified radical mastoidectomy - a procedure where the bony partition between the back part of the ear canal and mastoid is removed and an ossicualr reconstruction with repair of the eardrum is also performed.

Myelin - a substance which insulates nerves and allows for more efficient transmission of electrical signals

Obersteiner-Redlich zone - area where schwann cells meet oligodendroglia cells

Oligodendroglia cells - type of cell which coats the central segment of nerves

Ossicles - the three bones behind the eardrum, namely the malleus, incus and stapes

Ossicular reconstruction - a procedure to repair the ossicles so that sound transmission can occur to the inner ear.

Otoliths - small stones found in the otolith organs

Otolith organs – balance organs responsible for detecting linear acceleration of the head. These include the utricle and the saccule.

Paraganglia - cells located around the middle ear, jugular bulb or carotid artery in the neck which are thought to detect oxygen and carbon dioxide levels in the bloodstream.

Petrous apex - bone that is located deep to the inner ear

Petrous apex epidermoid - a cholesteatoma that arises from squamous epithelium that became entrapped within the petrous apex

Perilymph - another type of fluid found in the inner ear

Peripheral - near the inner ear

Radical mastoidectomy - a procedure done where the eardrum, malleus and incus are removed and the bony partition between the back part of the ear canal and mastoid is also removed.

Retraction - pertains to the act of pushing aside certain structures such as the brain.

Saccule - part of the inner ear responsible for gathering information relating to linear acceleration of the head

Schwann cells - type of cell which coats the peripheral segment of nerves and produces a substance called myelin

Semicircular canals - part of the inner ear involved in gathering information on head motion.

Sensorineural Loss - A type of hearing loss arising from the inner ear and/or nerve, which in most cases is permanent, due to aging, ototoxic drugs, noise exposure, etc. Hearing aids are the best remedy for a sensorineural loss.

Sigmoid sinus - a large vein found deep within the mastoid which collects blood from the brain and empties into the jugular bulb

Suboccipital approach - a hearing preservation approach which involves a craniotomy far behind the ear with retraction of the cerebellar portion of the brain which allows visualization of the posterior portion of the internal auditory canal.

Squamous epithelium - skin

Tinnitus - ringing in the ears

Translabyrinthine approach - an approach which involves an incision behind the ear and a craniectomy through the semicircular canals of the inner ear. This allows visualization of the posterior aspect of the internal auditory canal. Minimal to no retraction of the brain is required, however hearing is always lost.

Trigeminal nerve - the nerve which transmits information on facial sensation, not motion

Tympanic membrane - eardrum

Tympanoplasty - a procedure to repair the eardrum and the ossicles

Unilateral - on one side

Utricle - part of the inner ear responsible for gathering information relating to linear acceleration of the head

Vein - a vessel which carries blood away from other organs and to the heart. The red blood cells within veins have a lower oxygen content.

Vestibular - pertaining to the function of balance

Vestibular schwannoma - acoustic neuroma