Middle Ear Flashcards
What is the incidence of malleus ankylosis during primary surgery for otosclerosis
0.4- 1.6%.
What is the incidence of tympanic membrane perforation 6 months after pressure equalizing tube extrusion
0.5-2%.
What is the incidence of facial nerve paralysis in patients with chronic otitis media and cholesteatoma
1%.
What are the expected residual hearing levels after PORP and TORP
15 dB conductive hearing loss PORP; 25 dB conductive hearing loss TORP.
What % of congenital cholesteatomas are bilateral
3%.
In patients with chronic otitis media but not cholesteatoma, what level of hearing loss is associated with ossicular chain disruption or fixation
30 dB or more.
What is the rate of extrusion of middle ear prostheses
4- 7%.
What is the incidence of malleus ankylosis during revision surgery for otosclerosis
4.5- 13.5%.
What is the mean age of presentation for congenital cholesteatoma
4.5 years.
What % patients have erosion of the scutum with cholesteatoma
42%.
What % of cholesteatomas are complicated by a labyrinthine fistula
5 - I O%.
What is the overall success (accounting for extrusion, HL, and graft take) at 4 months using TORP or PORP
58% TORP; 64% PORP.
What % of cases of otosclerosis are bilateral
85%.
Why is stapedectomy dangerous in patients with Meniere’s disease
A dilated saccule may sit immediately beneath the footplate and be injured upon entry into the vestibule.
How do the surgical findings differ during removal of congenital cholesteatoma from removal of cholesteatoma associated with chronic suppurative otitis media
Absence of inflammatory changes/adhesions and easier removal with potential for complete preservation of the middle ear mucosa.
What are the indications for using plastic sheeting in middle ear surgery
Absence of mucosa on the promontory, in most of the middle ear, or in the middle ear cleft (except in the eustachian tube).
What are the indications for simple mastoidectomy
Acute coalescent mastoiditis with complications or acute mastoiditis that does not resolve after appropriate antibiotic therapy and myringotomy.
How should an extruded prosthesis be managed
Allow spontaneous extrusion; TM may heal and make a spontaneous connection.
What are the 2 parts of a cholesteatoma
Amorphous center surrounded by keratinized squamous epithelium.
What are the complications of lateral tympanoplasty
Anterior blunting, lateralization, epithelial pearls, canal stenosis.
What are the indications for performing a lateral tympanoplasty
Anterior or large perforations, revision tympanoplasty, or if the anterior canal wall is in the way.
What is the most commonly involved site of otosclerosis in the temporal bone
Anterior to the oval window at the fissula ante fenestrum.
What is the management of injury to the sigmoid sinus during mastoidectomy
Apply gentle pressure, place a Surgicel or Gelfoam patch, and continue with surgery.
In a child with spontaneous CSF leak to the middle ear, where is the leak most commonly located
Around the stapes footplate.
What are the options for surgical management of the chronically draining mastoid cavity
Autologous cultured epithelial graft (from buccal mucosa), large meatoplasty, revision mastoidectomy, reconstruction of canal wall with an aerated cavity, mastoid cavity obliteration, and mastoid/middle ear obliteration.
What is the inheritance pattern of otosclerosis
Autosomal dominant with incomplete penetrance (only 25 - 40% of carriers express the phenotype).
What does the “Blue Mantles of Manasse” refer to
Basophilic appearance on hematoxylin and eosin staining of bone in the active stage of otosclerosis.
What are the 2 types of tympanic membrane perforations
Central and marginal.
What are the boundaries of the facial recess
Chorda tympani laterally, upper mastoid segment of VII medially, bone of fossa incudis superiorly.
What factors predispose one to complications from OM
Chronic infection, history of mastoid surgery, cholesteatoma, diabetes, • • tmmunocompromtse.
What are the 2 types of cholesteatomas
Congenital and acquired.
What are the 3 principle theories regarding the etiology of cholesteatoma
Congenital theory (von Remak, 1854 and Virchow, 1855)~ metaplasia theory (Trolscht, 1873); migration theory (Habermann, 1888).
What is the most common cause of malleus ankylosis
Congenital.
Should a cholesteatoma be removed over a fistula
Controversial, in that leaving a piece of matrix to seal the fistula increases the risk of recurrent cholesteatoma, while completely removing the matrix and exposing the fistula increases the risk of hearing loss and vertigo.
What is a radical mastoidectomy
Conversion of the mastoid, antrum, and middle ear into a common cavity, with removal of the tympanic membrane, malleus, incus, chorda tympani, and mucoperiosteum.
What is a modified radical mastoidectomy
Conversion of the mastoid, epitympanum, and external auditory canal into a common cavity by removal of the posterior and superior external bony canal walls.
What is the most common complaint of patients with an epidural abscess/granulation tissue
Deep, constant pain in the temporal area that is very steroid responsive.
What are the radiographic findings of sigmoid sinus thrombosis
Delta sign on CT scan with contrast and central nonenhancement of the sigmoid sinus; decreased intraluminal signal on MRI with gadolinium.
What is the typical route of spread of cholesteatomas originating in anterior mesotympanum
Descend to the pouch of Von Troeltch, and may involve the stapes, sinus tympani, or facial recess.
In a patient with a cholesteatoma, what factors make presence of a fistula highly unlikely
Disease
What is a congenital cholesteatoma
Embryonal inclusion of undifferentiated squamous epithelium in the middle ear behind an intact TM, usually with no history of otitis media.
What are the intracranial complications of otitis media (OM)
Epidural abscess/granulation tissue, sigmoid sinus thrombosis, meningitis, brain abscess, subdural abscess.
What are the symptoms and signs of a poststapedectomy perilymph fistula
Episodic vertigo, especially with exertion, sensorineural hearing loss, loss of speech discrimination, and nystagmus with changes of air pressure on the TM.
What factors contribute to extrusion
Eustachian tube dysfunction (70%), graft failure, cartilage resorption.
What are the advantages of lateral tympanoplasty
Excellent exposure, high graft take rate (95%), most versatile approach.
What is the significance of pain in a patient with cholesteatoma or chronic otitis media
Expanding mass or empyema in the antrum.
How is this treated
Expedient elimination of infection.
What are the indications for staging a tympanoplasty without mastoidectomy
Extensive mucous membrane destruction, stapes fixation.
What are the 5 primary causes of conductive hearing loss after stapedectomy
Failure to recognize obliterative otosclerosis of the round window; displacement of the prosthesis after head trauma or large changes in middle ear pressure; necrosis of the long process of the incus; migration of the prosthesis in the oval window; and adhesions.
T/F: In cases of malleus fixation, mobilization of the malleus usually results in lasting hearing improvement
False.
What features on history distinguish FAO from profound SNHL
Family history of otosclerosis; progressive hearing loss usually of long duration; history of hearing aid use that is no longer beneficial or present use of a hearing aid with benefit beyond that which would be expected for the severity of the hearing loss; paracusis; and previous audiograms indicating an air-bone gap.
What are the terms used to describe involvement of the oval window and cochlea
Fenestral otosclerosis and retrofenestral otosclerosis, respectively.
What is the most common tumor of the middle ear
G lorn us tympanicum.
What is the prognosis after such an injury
Good if immediately recognized and treated.
What are the most common pathogens cultured from otorrhea after tympanotomy tubes in children younger than 3
Haemophilus influenza and Diplococcus pneumoniae.
What are the three most common organisms causing meningitis secondary to OM
Haemophilus influenzae, type 8, Streptococcus pneumoniae, Neisseria meningitides.
What are the disadvantages of the CWD procedure in the management of cholesteatoma
Healing is slower, indefinite periodic cleaning and dry ear precautions are required, and hearing aids are more difficult to fit in the meatus.
What are the advantages of using porous polyethylene prostheses over fitted autograft ossicles
Hearing is more stable, decreased incidence of residual and recurrent cholesteatoma.