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.
What is the significance of a white versus a blue floating footplate
Hearing success is much less in the presence of a white floating footplate (52°/o) versus a blue floating footplate (97%).
What can cause persistent cavity discharge after CWD procedures
High facial ridge, particularly large cavity, open middle ear space, inadequate meatal opening, poor postoperative care leading to infection.
What is the significance of sensorineural hearing loss after stapedectomy
If no tissue graft was used, 50% of SNHL will be due to fistulas and should be revised.
Revision stapedectomy is performed. What should be done with the original prosthesis
If possible, it should be left in place, and a second fenestra and prosthesis should be placed.
When is a CT scan obtained
If signs of progression arise while on IV antibiotics or if the patient presents with possible intracranial complications.
When is mastoidectomy indicated
If the CT scan shows coalescent mastoiditis and/or intracranial involvement.
How much more bone conduction will dental conduction provide than mastoid conduction
II dB.
What is the management of intraoperative violation of the labyrinth
Immediate application of a Gel foam patch or other tissue seal (other than fat).
When is mastoid and middle ear obliteration most appropriate
In a dead ear, without cholesteatoma.
How does the hearing impairment from malleus ankylosis differ from that of otosclerosis
In patients with malleus ankylosis, hearing impairment is mostly unilateral (78°/o); the air-bone gap is smaller (majority less than 20 dB); sensorineural hearing loss is more frequent, particularly at 4 kHz; acoustic reflex is more likely to be present on the contralateral ear and absent on the impaired ear.
When is stapedectomy contraindicated
In young children until it has been demonstrated that they are not prone to otitis media, in the presence of active middle or external ear disease or active URI, tympanic membrane perforation, Meniere’s disease.
Which portions of the ossicular chain are always removed in CWO procedures
Incus and head of the malleus.
Which ossicle is most commonly involved in patients with cholesteatoma
Incus.
What is the significance of the ability to hear a tuning fork placed on the teeth
Indicates that cochlear reserve is present and surgery may be beneficial.
What are the histopathologic findings of patients with FAO
Invasion of otosclerotic foci into the cochlear endosteum and the stapes footplate.
During stapedectomy, the entire stapes footplate falls into the vestibule. What should be done
It should be left in the vestibule, as attempts to retrieve it are more likely to cause damage than leaving the footplate where it is.
Where does this most often occur
Lateral semicircular canal (75% ).
What is the most common location for iatrogenic labyrinthine fistula formation during mastoidectomy
Lateral semicircular canal.
What are the disadvantages of the canal wall up (CWU) approach
Limited exposure of the anterior epitympanum, sinus tympani, and facial recess.
Which areas of the middle ear are most difficult to see during mastoidectomy
lnfrapyramidal and tympanic recesses.
What are the disadvantages of lateral tympanoplasty
Longer healing time, potential for anterior blunting or lateral healing, technically more difficult.
What are the 2 most important principles of CWD procedures
Lowering the posterior canal wall to create a round cavity and creating a large meatus.
What is the single most important factor affecting hearing results after CWO tympanomastoid surgery
Maintenance of a pneumatized space juxtaposed to the round window.
Which of these is associated with cholesteatoma
Marginal.
What is obliterative otosclerosis
Margins of the footplate cannot be seen or removed.
What virus is thought to play a role in the etiology of otosclerosis
Measles.
Which of these layers does otosclerosis involve
Middle endochondral layer.
If the CWU procedure is chosen, what are the indications for a 2”d look
Missing middle ear mucosa or extensive cholesteatoma.
What congenital ear malformation is most commonly associated with perilymph fistula in children
Mondini deformity.
What is the significance of hearing loss in the absence of middle ear effusion in patients with congenital cholesteatoma
Most lesions begin anterosuperiorly and extend posteriorly with growth. Hearing loss indicates posterior extension with involvement of the stapes superstructure and/or the lenticular process of the incus.
What genetic mutation has been implicated as a possible cause of otosclerosis
Mutation of the COLlA I gene on chromosome 17q.
What are the potential problems with a type IV tympanoplasty
Narrowing of the middle ear space and graft lateralization.
What is the advantage of using a laser for stapedectomy
No-touch technique with less risk of a floating footplate.
What are the indications for 2”d look surgery after removal of a congenital cholesteatoma
Obvious recurrent disease, unexplained deterioration in hearing, concern about the adequacy of the initial surgery or disease found to extend into the antrum or mastoid.
What type of cholesteatoma is most frequently found in the facial recess
One associated with a perforation below the posterior malleolar fold.
According to Sheehy, in which situations is the canal wall down (CWD) approach most appropriate
Only-hearing ear, very contracted mastoid, mastoid with a labyrinthine fistula, or presence of canal wall erosion due to disease.
What is the most common cause of perilymph fistula
Otologic surgery (stapedectomy).
How is far-advanced otosclerosis (FAO) defined
Otosclerosis with an air conduction threshold greater than 85 dB and a bone conduction threshold not measurable.
What are the three layers of the otic capsule
Outer periosteal layer, inner periosteal layer (endosteum) and the middle endochondral layer.
Where is dehiscence of the bony facial canal most common
Over the oval window.
What factor strongly correlates with survival and long term neurologic deficits in patients with a brain abscess
Patient’s level of consciousness at the time of diagnosis.
What features on physical exam distinguish FAO from profound SNHL
Patients with F AO more likely will have a soft voice with better quality than expected for the degree of hearing loss and the ability to hear a 512 Hz tuning fork placed on the teeth, dentures, or gums.
What is the most common postoperative complication of pressure equalizing tube insertion
Persistent otorrhea.
What vessels can be injured in the middle ear during tympanoplasty
Persistent stapedial artery, superficial petrosal branch of the middle meningeal artery, high-riding jugular vein, and anomalous carotid artery.
What are the most common reasons for mastoid surgery failure without recurrent cholesteatoma
Persistent suppurative disease in unexenterated air cells (most commonly at the sinodural angle and along the tegmen) and technical factors such as high facial ridge or meatal stenosis.
Other than the middle ear, where else may congenital cholesteatomas arise
Petrous apex, cerebellopontine angle, mastoid, external auditory canal.
What are the most common signs and symptoms of sigmoid sinus thrombosis
Picket fence fever, cannon ball infiltrates on CXR, torticollis, jugular foramen syndrome, otitic hydrocephalus.
What technique is employed during ossiculoplasty to decrease the risk of prosthesis extrusion
Placement of cartilage between the prosthesis and the tympanic membrane.
What techniques can be used to accomplish this
Placement of the fascia graft such that it does not obliterate the space between the eustachian tube orifice and the round window; placement of silastic crescent in the hypotympanum.
Unbeknownst to the surgeon, the dura is torn during mastoidectomy, and postoperatively, the patient develops a severe headache, followed by hemiplegia and coma. What has likely happened
Pneumocephalus~ torn dura can create a ball valve-like effect and trap air from the middle ear. Influx of air may occur during Valsalva or as a result of high intracranial negative pressure due to the rapid escape of CSF through the tear.
What is thought to cause congenital malleus ankylosis
Poor development of the epitympanic space leaves the head of the incus and malleus in close contact with the tegmen; a bony bridge can result between the epitympanum and the head of the malleus.
In patients with bilateral otosclerosis, which ear should be operated on first
Poorer hearing ear.
What are the most common sites of origin of primary acquired cholesteatomas
Posterior epitympanum, posterior mesotympanum, and anterior epitympanum (in descending order of frequency).
What conditions accelerate hearing loss in patients with otosclerosis
Pregnancy, estrogen replacement.
What are the 2 types of acquired cholesteatomas
Primary and secondary.
What is the difference between a primary and a secondary cholesteatoma
Primary usually occurs in the attic at Shrapnell’s membrane and starts as a retraction pocket; secondary is associated with chronic middle ear infection and TM perforations.
What are the early signs and symptoms of intracranial infection
Prolonged suppurative OM, fetid discharge and persistent pain despite adequate treatment, bony destruction of inner cortex of mastoid on CT scan.
What is a “perilymph gusher”
Rapid release of perilymph after stapes footplate fenestration due to pressure and fluid from the CSF compartment venting through the inner ear.
What are the most common reasons for recurrent conductive hearing loss after tympanoplasty
Recurrent perforation, blunting of the angle between the tympanic membrane and the external auditory canal, graft lateralization, graft thickening and adhesions, severe graft atelectasis.
What is “Schwartze’s sign”
Reddish hue on the promontory associated with otosclerosis.
What is the benefit of amputating the mastoid tip
Reduces cavity size and eliminates a dependent cavity area that is not visible.
What is the optimal treatment of malleus fixation
Removal of the head of the malleus and interposition of the incus between the manubrium and the stapes head.
What is the management of injury to the dura with CSF leak during mastoidectomy
Repair with temporalis fascia held in place with sutures or packing and continue with surgery; small tears can be managed with a Surgicel or Gelfoam patch.
In patients with bilateral otosclerosis and equal hearing loss, which ear should be operated on
Right-handed surgeon should work on the left ear (or patient preference).
What is the most common cause of failure using a fitted ossicle for middle ear reconstruction
Separation of the ossicle from the stapes.
What other techniques can help improve hearing results
Shielding the round window to increase the difference in sound pressure between the oval and round windows~ placing the graft directly atop the head of the stapes when the suprastructure is present; using a TORP or placing the graft directly on the stapes footplate when the suprastructure is not present (type IV tympanoplasty).
If a CWO procedure is used to treat a posterior-superior retraction cholesteatoma, what would be the most likely site of residual cholesteatoma
Sinus tympani.
What is the medical treatment for otosclerosis
Sodium fluoride, vitamin D.
What are the indications for using a TORP when the stapes suprastructure is present
Stapes tilted towards the promontory, partial arch necrosis, and unusually deep oval window niche where a PORP might contact the fallopian canal and/or promontory.
What are the most common pathogens cultured from otorrhea after tympanotomy tubes in children older than 3
Staphylococcus aureus and Pseudomonas aeruginosa.
What is the typical route of spread of cholesteatomas originating in the posterior epitympanum
Starting from Prussak’s space, penetrate posteriorly to the superior incudal space lateral to the body of the incus and progress to the aditus and the antrum.
What are the three most common organisms of OM that result in intracranial infections
Streptococcus faecalis. Proteus, Bacteroides fragilis.
What are the extracranial complications of OM
Subperiosteal (Bezold’s) abscess, petrositis, labyrinthitis, facial nerve paralysis.
What is the most common complication of acute mastoiditis
Subperiosteal abscess.
What is the significance of Tullio’s phenomenon after stapedectomy
Suggests that the prosthesis is too long and impinging on the saccule.
What is the Paiva flap
Technique used for mastoid obliteration where the soft tissue off the back of the ear is swung into the mastoid.
How is the round window evaluated for normal movement
The membrane is not readily visible, so a drop of saline is placed in the niche and movement is seen as a change in light reflection on the meniscus when the prosthesis is palpated.
Why is it important to saucerize the cavity margins
The soft tissues and auricle will assume a more medial position during healing, resulting in a smaller cavity.
In patients where one ear has previously been operated on and hearing loss is equal bilaterally, which ear should be operated on
The unoperated ear.
At what age does otosclerosis peak in incidence
Third decade.
What is the most common etiology of spontaneous CSF leak to the middle ear in adults
Through a defect in the mastoid tegmen secondary to a meningoencephalocele.
What is the purpose of the plastic sheeting in these conditions
To prevent adhesions from forming and to allow mucosa to grow over denuded areas.
T/F: Postoperative hearing improvement and reperforation rates are similar for medial and lateral tympanoplasty
True.
T/F: The modified radical mastoidectomy does not involve a tympanoplasty
True.
T/F: The mastoid bones of patients with congenital cholesteatoma are most often well-aerated
True.
T/F: Histologically, the bony structures are normal, without evidence of otosclerosis, in cases of malleus ankylosis
True.
What is the treatment for uncomplicated acute mastoiditis
Tympanocentesis for culture and IV antibiotics.
Is the acoustic reflex present in patients with otosclerosis
Usually it is absent bilaterally, even if the disease is unilateral.
What is Tullio’s phenomenon
Vertigo with loud noise.
