Download Otosclerosis

Otosclerosis
Introduction
- Otosclerosis : fibrous osteodystrophy of the human otic capsule
- May  : CHL , SNHL and mixed HL ( progressive HL )
- Cause ( suggest ) : Hereditary , endocrine , biochemical , metabolic ,
infectious ( eg. Measles ) , traumatic , vascular & autoimmune
Embryology
- At 4 th wk : otic capsule arises from mesenchyme
- At 8 th wk : cartilaginous framework is begun
- At 16 th wk : endochondral bone replacement BUT in some people ; complete
bone replace not occur & leave cartilage frame work
- Fissula ante fenestram (ant to OW ): last area bone replacement , this region is
affected in 80-90% of pt
Histology 3 form:
1 otospongiosis ( early phase ) : active phase มี ostetoblast , histiocyte,osteclast ซึ่ง
resorb bone around preexisting bl vv ทำให้มมี vascular channel & dilatation of
microcirculation ซึ่ง otoscopic exam  Schwartz sign
2 transitional phase : osteocytes becomes more involve  amorphous ground
substance
3 otosclerosis ( late phase ) : sclerotic , dense bone
Pathophysiology
CHL : due to fixation of stapes footplate มักเริ่ ม involve ที่ Fissula ante fenestram
นอกจำกนี้ ้ำกมีกำร involve only stapes footplate & spare annular lig ซึ่งเรี ยกว่ำ Biscuit
Footplate ซึ่ง้ำกมี stapes op จะทำให้มเสี่ ยงสู งต่อ SNHL
SNHL มี 3 mech :
1 toxic metabolite injury to neuroepi
2 vascular compromise
3 direct extension to cochlea
Shambaugh suggest criteria to identify pt with SNHL due to OS
1 Schwartze sign in either ear
2 FH of OS
3 Unilat CHL consistent with OS & bilat , sym SNHL
4 Audiogram with a flat or cookie – bite curve with excellent discrimination
5 progress pure cochlear loss beginning at he usual age of onset for OS
6 CT show demineralization of cochlea typical of OS
7 stapedial reflex demonstrating biphasic on-off effect seen before stapedial fixation
นอกจำกนี้ OS อำจมำ present ดมวย dizziness ~ 30% pt เนื่องจำกมี involve lateral
semicircular canal อำกำรทำง vestibular ไม่ค่อย severe ( dizziness associate OS  OS
inner ear syn ) ตมอง DDX : Meniere dz , superior semicircular canal dehiscence
(SSCD)
Epidemiology
- OS  autosomal-dominant hereditary
- ส่วนให้ญ่พบใหน Caucasians pt และ Associate FH ( Clayton et al. : OS ass.
COL1a1 gene )
- OS advance more progress in female > male , female : male 2:1
- Age variable , HL between 15-45 yr ( ~ 33 yr )
- ใหน Juvenile OS : Dz progress than adult
- Hormonal factor may play a role , clinical worsen during pregnancy
History & Physical examination
- OS present with slowly HL over progressive yrs
- Pt มักจะไดมยน
ิ เสี ยงดีใหน noisy situation ( paracusis of Willis )
- Present tinnitus ~ 75 %
- Otoscopy : TM is normal in most pt , Schwartze sign may be present
- Tuning fork : พบ CHL  Rinne - ve
Initial phase  Rinne - ve may be limited to 256 Hz
Progress Dz มี Footplate fixation  Rinne - ve at 512 Hz & 1024 Hz
( air-bone gap ~ 10-15 dB at 256 Hz และ ~ 20-25 dB at 512 Hz  Rinne – ve )
Weber test : lateralize to greater degree of CHL
Audiologic testing
Audiogram :Cahart notch is most common seen in OS Speech discrimination
is excellent
Tympanogram : Impedance can show reduce TM compliance ( type A ,As )
Stepedial reflexes : normal or abnormal depending degree of fixation ( diphasic
reflex with on-off pattern , absent reflex)
Vestibular test ควรจะทำใหน case with dizziness เพื่อที่จะ R/O Dz อย่ำงอื่น
HRCT : assess osicular chain , bony labyrinth ซึ่ งพบว่ำมี
- Early Dz : radiolucent areas around Cochlea  Halo sign
- Mature case : diffuse sclerosis
CT scan helpful R/O middle ear Dz : mass ,vascular anomalies
Differential diagnosis
OS : progressive CHL or mixed HL with absence of trauma or infection , TM
normal (may be Schwartze sign ) Carhart notch highly suggest OS
Definite Dx : made during exploratory tympanotomy
The most common conditions that mimic OS :
1. ossicular chain discontinuity :
พบใหน pt with Hx of recurrent COM ซึ่งจะทำให้มมี incus necrosis , TM may be
normal or thickness and sometime abnormal detected by tymanogram
นอกจำกนี้พบว่ำมี A-B gap ร่ วมดมวย เนื่องจำกมี fibrous union at SI jt โดยจะพบที่ high
frequency > low frequency
2. exert a mass effect on TM or ossicular chain
3. Conginital stapedial footplate fixation : พบที่อำยุ 3 ปี แต่ใหนบำงรำยอำจเพิ่ง detectไดมที่
อำยุ ~ 10 ปี  juvenile OS ( De la Cruz )
4. Malleus head fixtion : cause infection , tympanosclerosis โดยที่ malleus fix
กับ epitympanum ทำให้ม immobile of all ossicle
5. Paget Dz (osteitis deformans ) : histology similar OS but Paget Dz begin
involve periosteal layer & involve endochondral bone last
6. Osteogenesis imperfecta (van der Hoeve-de Kleyn syndrome) : autosomal
dominant defect of osteoblast activity ซึ่ งพบว่ำมี stapes fixation & unique blue
sclera ~ 40-60%
Management
90 % of pt with histologic evidence of OS  asymptomatic
In symptomatic pt : CHL & SNHL begin at 20 yr and progress , CHL stabilize at a
maximum 50-60 dB
Amplification
- Typical HA , bone-anchored HA (BAHA)
- ใหชมใหน pt with HL & not be suitable candidate for Sx
-
ข้ อดี
o Avoid potential risk of profound HL from Sx
-
ข้ อเสีย
o Usually not used at night
o Physical sensation of device in EAC  negative sensation
- In pt with severe to profound SNHL อำจใหชม cochlear impant
Medical management
- In 1923 Escot : first to suggest use calcium fluoride
- Shambaugh use sodium fluoride for stabilize OS : fluoride ion replace
hydroxyl radical form  stable fluorapatite complex instead of hydroxyapatite
crystal (fluorapatite complex resist osteoclast activites )
- Recommended Dose 20-120 mg per day
- Evaluate efficacy :
o Disappear Schwartze sign
o Stabilization of hearing
o Improvement CT appearance of otic capsule
- Side effect :
o usually minor  GI irritation ( prevent : low dose , enteric coat )
o occasional complaint of jt , bone , muscle pain resolves with temporary
discontinuation of therapy
o Rare : fluid retention , cutaneous eruption & eye problem
- 80 % pt  improve or show no worsen symptoms
Surgical management
- Stapedectomy is indicated when the stapes fix โดยดูจำก A-B gap at least 30 dB
for speech frequency & negative Rinne test at 256 , 512 Hz ( Shambaugh)
- Successful stapedectomy : correct CHL , remove Carhart’snotch & closure
pre-op A-B gap
Factors
- Age :
o In the young pt พบว่ำมี anomalies of malleus or incus สูงโดยเฉพำะ
congenital OS (25%)> juvenile OS (3%)
o In older pt พบว่ำมี poorer result in High frequency range ้ลังจำกผ่ำตัด
- Lifestyle & occupation :
o Repeat exposure barometric pressure change (scuba diver)  greater
risk to post op fistulae , prosthesis dislocate
o Pt whose work or hobbies dictate excellent balance  questionable
candidate for Sx
o Pt whose work about taste (chef )  recommend to amplification
because risk to stretching or cutting chorda tympani n.
-
Otologic problem
o Meniere Dz & OS : greater risk of cochlear HL after stapedectomy
o TM perforate & OS : shoukd be closure TM befofre stapedectomy and
พบว่ำ incidence SNHL ค่อนขมำงสูง after stapedectomy
o Severe Eustachian tube dysfunction & cholesteatoma : not good
candidate for stapedectomy
Contraindication( Shambaugh)
- Poor speech discrimination & Hx of vertigo in recent month (because
possibility of endrolymohatic hydrop labyrinth open)
- Pt with only hearing ear should be avoid (relative)
- Pt with ME infection or effusion (absolute)
Technique of stapedectomy
Preoperative preparation
1 patient counseling
- option : observation , fluoride use and trial hearing aid
- Pt must be informed of risk ot stapedectomy
o Post op deafness of less than 2%
o Stretching or contusion chorda tympani  alteration test ( symptom
can self limit & disappear in a few wk or month )
o Dehiscence of fallopian canal over OW จะทำให้มมี expose or prolapsed
Facial nerve risk to injury
o Post op TM perforate ~ 2%
o Acute balance disturbance is common after stapedectomy , can resolve
in 3-7 days , long term is rare
2 Anesthesia
- can be perform under LA or GA
- LA : slightly less bleeding & can assess intraoperative hearing
- GA : pt prefer
- The EAC is infiltrated with 1% lidocaine with 1 :100,000 epinephrine for
hemostasis
Operative
1 obtaining the tissue graft
- autograft tissue used to cover the OW
o vein ; harvested from back of hand
o fat ; harvested from ear lobule
o Temporalis fascia ; harvested through a small incision above & behind
ear
o Perichondrium ; harvested from tragus
2 Exposure of the OW
- Flap is elevated from 6 o’ clock to 12 o’ clock
- Special care : separated the attachment of posterior fold of pars tensa to mid
point of sulcus posteriorly
- In most ears, to gain exposure OW & stapes  scutum ( medial most
posterosuperior EAC wall ) is removed
3
1
2
3
4
1
2
3
Removal of the Stapes Superstructure
separate SI jt , using angled jt knife
cut stapes tendon , using middle ear scissor
remove superstructure : 3 technique
o In footplate is rigidly fixed : fracture downward using sharp pick in the
cup in head of stapes  ( Fx at base of crura ) In some surgeon create
safety hole at footplate prior Fx
o Using a microcrurotomy bur in microdrill to sever crura
o Using Argon or CO2 laser vaporize superstructure
Footplate removal and Creation of a Fenestra : 3 option
total footplate removal
o mucosa is removed from footplate & surrounding bone
o create small hole at central footplate using fine pick or laser and then
footplate cut across
o Removed piece of footplate , avoid dropping fragment into vestibule or
aspirate perilymph
Posterior half footplate removal
o Similar to total footplate removal but only Posterior half is removed
o Less postoperative vertigo and better high frequency hearing
Small fenestra stapedectomy (stapedotomy)
o Using Argon or CO2 laser , micropick , microdrill
o Create hole ~ 0.7 mm diameter for ideal prosthesis ~ 0.6 mm diameter
o Laser creating a rosette of opening
Stapedotomy
Stapedectomy
5 Tissue Seal of the Oval Window
o Tissue seal : vein , perichondrium , fascia
o No living tissue : Gelfoam
6 Prosthesis Placement categorize prosthesis into 4 group :
1 Cup piston prosthesis of Shea & Robinson prosthesis
2 Original Shea Teflon piston prosthesis
3 McGee/Fisch-type piston prosthesis
4 House wire prosthesis
1
2
3
4
Postoperative care
 Given adequate analgesic
 Avoid straining or blowing nose
 Antibiotic are not routine
 Keep dry ear until healing TM
Special Problem During & After Stapedectomy
Floating Footplate Problem
- nonfixed stapedial footplate after the crural arches have been Fx
- Removing floating footplate : use diamond drill or laser at promontory edge of
OW  Small Rt angle hook to lift footplate
- If footplate depress into vestibule  graft & prosthesis place lat to depressed
footplate
Obliterate Otospongiosis
- occur at margins of OW  drill out is required
- approximate locate OW by crura & fallopian canal
- Use small diamond drill , Argon or CO2 laser is carefully thinned down unltil
blue area and made round opening
Biscuit Footplate
- the thickened footplate with well-defined margins produced by a primary focus
in footplate
- Use small diamond drill , Argon or CO2 laser cut across center until foot plate
can be extracted in 2 piece
Dehiscent , Prolapsed Facial nerve
- facial nerve protruding down over the footplate
- a small fenestra can be made in the footplate
- more difficult & dangerous problem to revision stapedectomy ( become
embedded & pull down by fibrosis )
Postoperative Granuloma
- granuloma develop within the first 2 wk postop cause sudden hearing loss &
disturbance of balance
- Hallmark finding: grayish-red mass in the posterosuperior quadrant of TM
- Should be explore & remove and then cover by living tissue
- Early operation can save hearing
Fixed incus and / or Malleus
-
Ankylosis of incus and / or Malleus occur by itself or combine stapes
-
Prolong fixed stapes Ankylosis of incus and / or Malleus
- Should be correct Fixed incus and / or Malleus :
o If body incus & not malleus fix separate incus from head stapes & remove
o If head malleua & not incus fix cut neck malleus & remove head malleus
o If both body incus&head malleus fixremove both and then insert TORP
o If incus and/or malleus,not stapes fixremove then insert PORP
TORP
PORP
Round Window Closure
- Partial involvement of margin of round window is common
- Tiny opening of RW or may be fibrous occlude RW but not disturb hearing
- Complete bone closure RW with stapes ankylosis  cause severe MHL ;
Stapedectomy can improve hearing , Attempt open RW should be avoid
Fracture of the Long Process of the Incus
- reconstruction by TORP with wire
Acut otitis media
- immediate postoperative period
- culture & appropriate ATB
- post op TM perforate should be treated by ATB & rare require Sx repair
Perilymph Gusher ; rare
- profuse flow of perilymph when open vestibule อันเนื่องจำก abnormal of
cochlear aqueduct and / or IAC
- elevate head of table to reduce pressure, usually stop flow of perilymph
- seal OW by tissue graft and then place prosthesis
- bed rest and elevate head 30 degree until dry ear 24hr
- may be lumbar drain is placed
- complicationmay permanent cochlear loss
- further operation on this ear or other ear  contraindication
Facial palsy
- facial paralysis of Bell’s palsy can occur 5-7 d after stapedectomy owing to
activation of Herpes infection
- in most case recovery in one to several wk
- Postoperative facial palsy treat with large coticosteroid as idiopathic Bell’s
palsy
- Decompression of nerve might be indicate in rare case
Postoperative Perilymh fistula
- rare ; cause  immediate &late cochlear loss
- symptom: endolymphatic hydrop
- should be explore ME , avoid enter to vestibule
- found fistulae and then seal by CNT graft
- prognosis : vertigo is favorable ; hearing is poor
- Perilymh fistula is more common after wire& Gel foam or wire fat
stapedectomy
Postoperative Follow-up
- 2-4 wk post op  good fain in hearing & discrimination
- Best level of hearing ~ 3 mo-1yr (evaluate by audiogram)
THANK YOU
BY
PORNTHAPE KASEMSIRI
Aj SUTHEE , Advisor
Ref : Bailey 4th edition , Glasscock-Shambaugh 5th edition