Otology Flashcards
What are the five 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
- Adhesions
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
- Active URI
- tympanic membrane perforation
- Meniere’s disease.
What psychological problems are contraindications to cochlear implantation?
- Organic brain dysfunction
- mental retardation
- psychosis
- unrealistic expectations.
What is the incidence of malleus ankylosis during primary surgery for otosclerosis?
1-2%.
What are the expected residual hearing levels after PORP and TORP?
15 dB conductive hearing loss PORP; 25 dB conductive hearing loss TORP.
What is the incidence of ossification after pneumococcal meningitis?
20-30%.
What percent of patients will have improved tinnitus and hearing after endolymphatic sac surgery?
50% experience improvement in tinnitus and 30-40% experience improvement in hearing.
What percent of patients will have new bone growth covering the round window niche and membrane during cochlear implantation?
50%.
What is the incidence of malleus ankylosis during revision surgery for otosclerosis?
5-14%.
What percent of patients have improvement of vertigo after endolymphatic sac surgery?
70% experience complete relief, 20% experience decreased vertigo.
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 a congenital cholesteatoma from removal of a 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 complications of lateral tympanoplasty?
Anterior blunting, lateralization, epithelial pearls, and 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.
Where is the endolymphatic sac?
Anterior to Trautmann’s triangle within the dura, medial and inferior to the posterior sec.
Which way is the sigmoid sinus retracted in the retrosigmoid approach to vestibular nerve section?
Anteriorly.
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.
What are the two most important landmarks in the middle fossa approach to the internal auditory canal?
Arcuate eminence and hiatus for the greater superficial petrosal nerve.
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.
Which of these is superior in complete elimination of vertigo?
Both are equally effective.
Which laser can be used on the tympanic membrane to treat atelectasis?
Carbon dioxide laser.
Where is the safest place to create an opening in the stapes footplate?
Central area.
What are the boundaries of the facial recess?
Chorda tympani laterally, upper mastoid segment of VII medially, and bone of fossa incudis superiorly.
A 45-year-old man is being evaluated for cochlear implantation. He has a long history of chronic ear disease that is now dormant and has a modified radical mastoid cavity. What other procedures may be considered in conjunction with cochlear implantation?
Close the external auditory canal and obliterate the mastoid and middle ear.
What are the surgical landmarks for the tympanic segntent ofVII?
Cochleariform process, oval window, pyramidal process, semicanal for the tensor tympani, vertical groove on promontory for the tympanic nerve.
What is the best surgical approach for facial nerve exploration in a patient with a temporal bone fracture distal to the geniculate ganglion with intact hearing?
Combined transmastoid/middle fossa approach.
What approach is most often used for longitudinal fractures?
Combined transmastoid/middle fossa.
What are some clinical clues to an aberrant facial nerve?
Congenitally malformed auricle, ossicular abnormalities, craniofacial anomalies, and conductive hearing loss.
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 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 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.
Which complication is more likely in patients with cochlear dysplasia who undergo cochlear implantation?
CSF leak.
What is the primary disadvantage of the translabyrinthine approach?
Destroys hearing permanently.
What increases the likelihood of headaches after the retrosigmoid approach?
Drilling out of the medial portion of the lAC.
What are the surgical options for treatment of Meniere’s?
Endolymphatic shunt, destructive labyrinthectomy, and vestibular nerve section.
Which of these is the only surgical procedure considered in an only-hearing ear?
Endolymphatic shunt.
Which of these is most commonly performed?
Endolymphatic shunt.
A patient with Meniere’s disease and profound SNHL is being evaluated for cochlear implantation. She still has infrequent episodes of vertigo. What test should be ordered prior to surgery?
ENG.
What are the signs and symptoms of a pos1stapedectomy perilymph fistula?
Episodic vertigo, especially with exertion, SNHL, loss of speech discrimination, and nystagmus with changes of air pressure on the TM.
What factors contribute to extrusion of middle ear prostheses?
Eustachian tube dysfunction (70%), graft failure, and cartilage resorption.
What are the advantages of lateral tympanoplasty?
Excellent exposure, high graft take rate (95%), and most versatile approach.
What are the indications for staging a tympanoplasty without mastoidectomy?
Extensive mucous membrane destruction, stapes fixation.
What structures are resected in a subtotal temporal bone resection?
External auditory canal, middle ear, petrous bone, TMJ, and parotid gland with facial nerve.
True/False: Presence of PETs is a contraindication to cochlear implantation.
False.
True/False: Surgery is contraindicated in children with unilateral atresi•a.
False: Many will operate if the patient is likely to achieve a residual conductive deficit of 30 dB or less.
What are the most common complications of cochlear implantation?
Flap complications, electrode dislocation or malinsertion, facial nerve injury, and stimulation of facial nerve postoperatively.
When is surgical exploration indicated after temporal bone fracture?
For massively displaced fractures with compromise of the carotid artery or VII; or for VIIth nerve paralysis with >90% degeneration documented on electroneurography (ENoG) within 14 days of the injury.
What is the success rate of vestibular nerve section?
For the middle fossa approach, complete elimination of vertigo is achieved in >8o%; for the posterior approaches, complete elimination of vertigo is achieved in >70%.
What is the prognosis after such an injury?
Good if immediately recognized and treated.
What are the landmarks for identification of the lAC during middle fossa approach to vestibular nerve section?
Greater superficial petrosal nerve, malleus head, and superior SCC.
How is the facial nerve identified using the tympanic nerve?
Groove for the tympanic nerve is followed superiorly to the cochleariform process.
What are the disadvantages of the canal-wall-down 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.
Following acoustic neuroma resection, what problem do patients perceive as most troublesome?
Hearing loss.
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%) versus a blue floating footplate (97%).
What are the most common injuries encountered on surgical exploration?
Hematoma and contusion with bony spicules impinging on the nerve sheath.
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 condition increases the likelihood of this happening?
History of meningitis.
What if the nerve is only partially transected?
If greater than 1/2 remains, reapproximate the remaining nerve and perform regional decompression. If less than 1/2 remains, remove the injured segment and repair as with complete transection.
What is the significance of SNHL 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.
What is Donaldson’s line?
Imaginary line in the plane of the horizontal SCC back to the sigmoid sinus marking the top of the endolymphatic sac.
What is the management of intraoperative violation of the labyrinth?
Immediate application of a Gelfoam patch or other tissue seal (other than fat).
What is the management of intraoperative facial nerve transection?
Immediate repair with primary anastomosis if possible.
When is mastoid and middle ear obliteration most appropriate?
In a dead ear, without cholesteatoma.
How is electrocochleography helpful prior to destructive surgery for Meniere’s disease?
In patients with unilateral disease, abnormalities in the asymptomatic ear (SP:AP >35%, distorted CM with after-ringing) predict development of hydrops in that ear.
What are the reasons for persistent conductive hearing loss after aural atresia repair?
Inadequate mobilization of the ossicular mass from the atretic bone, an unrecognized incudostapedial joint discontinuity, or a fixed stapes.
What are the indications for surgical treatment of BPPV?
Incapacitating symptoms >1 year, confirmation of BPPV with Dix-Hallpike on at least three visits, failure of conservative treatment, normal head MRI.
Which portions of the ossicular chain are always removed in canal-wall-down procedures?
Incus and head of the malleus.