Otosclerosis Otosclerosis

Muneeb kosvi131/2012MAMC

Background Background Definition Definition

Hereditary localized disease of Hereditary localized disease of bony labyrinth resultung in bony labyrinth resultung in

fixation of the ossicles (stapes) and fixation of the ossicles (stapes) and conductive hearing loss.conductive hearing loss. Bilateral (70-85%)Bilateral (70-85%)May have sensorineural component May have sensorineural component

if cochlea is involved.if cochlea is involved.

Bony labyrinthBony labyrinth

Periostel layer : covers the bony labyrinthEndostel layer : innermostEnchondral layer : develops fro cartilage and later ossifies into bone.

But some islands remain unossified and later replaces the normal dense enchondral layer by irregularly laid spongy bone.

Etiology Etiology

Exact cause is unknown however many theories have Exact cause is unknown however many theories have been proposed such as been proposed such as

Anatomical, bony labyrinth is made of Anatomical, bony labyrinth is made of enchondral layer which is subjected to very enchondral layer which is subjected to very little change in life but some areas of cartilage little change in life but some areas of cartilage are activated to form new spongy bone and are activated to form new spongy bone and one such area is one such area is fissula ante fenestram, lying fissula ante fenestram, lying in front of the oval windowin front of the oval window

Heredity: 50% cases with autosomal Heredity: 50% cases with autosomal dominant trait dominant trait

Race: whites are affected more than blackRace: whites are affected more than black Gender: F:M=2:1, but in India M>F and Gender: F:M=2:1, but in India M>F and

Increase progression during pregnancyIncrease progression during pregnancy Age: 20-30 years, rare before 10 and after Age: 20-30 years, rare before 10 and after

40 years40 years

Types of otosclerosisTypes of otosclerosis

Stapedial type: Stapedial type: Involves oval windowInvolves oval window Most common typeMost common type Conductive deafness occurConductive deafness occur

Cohlear type:Cohlear type: Involves round window and other parts of otic capsuleInvolves round window and other parts of otic capsule May cause sensorineural loss due to liberation of toxic material in inner earMay cause sensorineural loss due to liberation of toxic material in inner ear

Histological type:Histological type: Remain asymptomaticRemain asymptomatic Neither conductie nor sensorineural lossNeither conductie nor sensorineural loss

based on area around oval window it is further divided into: based on area around oval window it is further divided into: 1.anterior focus: in front of oval window1.anterior focus: in front of oval window2.posterior focus: behind oval window2.posterior focus: behind oval window3.circumferential: around the margin of stapes footplate3.circumferential: around the margin of stapes footplate4.biscuit type: in footplate but annular ligament not involved4.biscuit type: in footplate but annular ligament not involved5.obliterative: completely obliterate oval window5.obliterative: completely obliterate oval window

PathologyPathology

Two phases of diseaseTwo phases of disease Active (otospongiosis phase)Active (otospongiosis phase)

Osteocytes, histiocytes, osteoblastsOsteocytes, histiocytes, osteoblasts Active resorption of boneActive resorption of bone Dilation of vesselsDilation of vessels Lot of cement substance which stains Blue with H&E stain Lot of cement substance which stains Blue with H&E stain

called as BLUE MANTLEScalled as BLUE MANTLES

Mature (sclerotic phase)Mature (sclerotic phase) Deposition of new bone (sclerotic and less dense than normal Deposition of new bone (sclerotic and less dense than normal

bone)bone)

PathophysiologyPathophysiology

Conductive hearing loss- Conductive hearing loss- oval window oval window sclerosis.sclerosis.

SNHLSNHL - Hyalinization of - Hyalinization of spiral l igamentspiral l igament , , toxins.toxins.

Vestibular symptoms- Vestibular symptoms- degeneration of degeneration of scarpa’s ganglionscarpa’s ganglion . Soluble toxic . Soluble toxic substancessubstances

Symptoms Symptoms Hearing lossHearing loss: Slowly progressive, painless, bilateral : Slowly progressive, painless, bilateral

(80%), asymmetric, conductive hearing loss.(80%), asymmetric, conductive hearing loss.

TinnitusTinnitus: 75% patients and seen commonly in cochlear : 75% patients and seen commonly in cochlear

and active lesion and is roaring, hissing typeand active lesion and is roaring, hissing type

Paracusis Willissi: patient hear better in noisy

surroundings.

Vestibular symptoms: uncommon

Speech: quiet voice and low volume

The age of onset of hearing loss is youngThe age of onset of hearing loss is young History of significant ear infections makes the History of significant ear infections makes the

diagnosis of otosclerosis less likely. diagnosis of otosclerosis less likely. 25% of patients present with some vestibular 25% of patients present with some vestibular

complaints complaints

Paracussis willissiParacussis willissi

when the condutive loss reaches level of 25-30db patient find it difficult to understand speech. But in noisy enviorment people with normal hearing raise their voices above the noise level, so that they can remove the masking effects of the noise, and this level of speech sound is above the threshold of the patient with conductive deafness.

DiagnosisDiagnosis History:History:

Women in her 20s or 30sWomen in her 20s or 30s Conductive or Mixed hearing lossConductive or Mixed hearing loss

Slowly progressive, Slowly progressive, Bilateral (80%)Bilateral (80%) asymmetric asymmetric

Tinnitus (75%)Tinnitus (75%) Vestibular symptoms (25%) Vestibular symptoms (25%) 2/32/3 rdrd patients have a positive family hisrory patients have a positive family hisrory

ExaminationExamination OtomicroscopyOtomicroscopy

Tm appears normal and mobileTm appears normal and mobile Schwartze sign: seen only in 10%Schwartze sign: seen only in 10%Reddish hue ay be seen on the promontery through the Tm Reddish hue ay be seen on the promontery through the Tm

which is indicative of active focus and increased vascularitywhich is indicative of active focus and increased vascularity

Tuning fork testsTuning fork tests Rinne:Rinne:

Hearing loss progresses form low frequencies to high Hearing loss progresses form low frequencies to high frequenciesfrequencies

256, 512, and 1024 Hz TF should be used256, 512, and 1024 Hz TF should be used 256 Hz – negative test indicates at least a 20 dB ABG256 Hz – negative test indicates at least a 20 dB ABG 512 Hz – negative test indicates at least a 25 dB ABG512 Hz – negative test indicates at least a 25 dB ABG

Weber test: laterization to ear with greater hearing lossWeber test: laterization to ear with greater hearing loss Absolute bone conduction: may be normal but decreased in Absolute bone conduction: may be normal but decreased in

cochlear otosclerosiscochlear otosclerosis

AudiometryAudiometry

TympanometryTympanometry Impedance testingImpedance testing

Acoustic reflexesAcoustic reflexes Pure tonesPure tones

AudiometryAudiometry Impedene audiometryImpedene audiometry

Early disease shows Type A tympanogramEarly disease shows Type A tympanogram Progressive stapes fixation result in As curveProgressive stapes fixation result in As curve

Acoustic reflexAcoustic reflex In normal person: Sustained decrease in In normal person: Sustained decrease in

compliacne till the stimulus last.compliacne till the stimulus last. In otosclerosis (early stage): biphasic on-off In otosclerosis (early stage): biphasic on-off

pattern seen in which brief increase in pattern seen in which brief increase in compliance at onset and termination of compliance at onset and termination of stimulusstimulus

In otosclerosis (late): reflex is absentIn otosclerosis (late): reflex is absent

Pure tone audiometryPure tone audiometry Most useful audiometric test for otosclerosisMost useful audiometric test for otosclerosis

Characterizes the severity of diseaseCharacterizes the severity of disease Frequency specificFrequency specific

Low frequencies affected first(Below 1000 Hz)Low frequencies affected first(Below 1000 Hz) Air line flattens with disease progressionAir line flattens with disease progression Carhart’s notchCarhart’s notch

Hallmark audiologic sign of otosclerosisHallmark audiologic sign of otosclerosis Decrease in bone conduction thresholdsDecrease in bone conduction thresholds

5 dB at 500 Hz5 dB at 500 Hz 10 dB at 1000 Hz10 dB at 1000 Hz 15 dB at 2000 Hz (maximum)15 dB at 2000 Hz (maximum) 5 dB at 4000 Hz5 dB at 4000 Hz

One element in bone conduction is inertia which One element in bone conduction is inertia which is due to weight of ossicular chain & stapes is due to weight of ossicular chain & stapes vibrate out of phase with the skull as a whole vibrate out of phase with the skull as a whole when we place vibrating tuning fork but due to when we place vibrating tuning fork but due to stapes fixation it is no longer free to vibrate so stapes fixation it is no longer free to vibrate so inertial component of bone conduction is lost inertial component of bone conduction is lost and bone conduction decreases.and bone conduction decreases.

Effect may disappear after stapedectomy and Effect may disappear after stapedectomy and this phenomenon is called over –closure of A-B this phenomenon is called over –closure of A-B gap. It means after surgery only conduction gap. It means after surgery only conduction threshold are measured threshold are measured

Classical audiometric findingsClassical audiometric findings

C = conductive hearing loss for low C = conductive hearing loss for low frequenciesfrequencies

= cahart’s notch= cahart’s notch A = acoustic reflex (diphasic/absent)A = acoustic reflex (diphasic/absent) R = rinne test negativeR = rinne test negative T = Typanogram (A/As)T = Typanogram (A/As)

Computed tomography (CT) of the Computed tomography (CT) of the temporal bonetemporal bone Pre-opPre-op

Characterize the extent of otosclerosisCharacterize the extent of otosclerosis Evaluate for enlarge cochlear aqueductEvaluate for enlarge cochlear aqueduct It reveal normal round window and normal mastoid It reveal normal round window and normal mastoid

pneumatization.pneumatization.

Post-opPost-op prosthesis dislocationprosthesis dislocation

Differential diagnosisDifferential diagnosis

Ossicular discontinuityOssicular discontinuity conductive loss of 60 db usually without conductive loss of 60 db usually without

sensorineural componentsensorineural component flaccid tympanic membrane on pneumatic flaccid tympanic membrane on pneumatic

otoscopyotoscopy type Ad tympanogramtype Ad tympanogram

Differential diagnosisDifferential diagnosis

Congenital stapes fixationCongenital stapes fixation Family history less likely (10%)Family history less likely (10%) usually detected in the first decade of lifeusually detected in the first decade of life 25% incidence of other congenital anomalies 25% incidence of other congenital anomalies

(3% for juvenile otosclerosis)(3% for juvenile otosclerosis) non-progressive CHLnon-progressive CHL

Differential diagnosisDifferential diagnosis

Malleus head fixationMalleus head fixation when when congenitalcongenital, associated with other , associated with other

stigmata (aural atresia)stigmata (aural atresia) presence of presence of tympanosclerosistympanosclerosis pneumatic otoscopypneumatic otoscopy almost always associated with type As almost always associated with type As

tympanogram (only in advanced otosclerosis)tympanogram (only in advanced otosclerosis)

Differential diagnosisDifferential diagnosis

PagetPaget ’’s diseases disease - diffuse involvement of the bony skeleton- diffuse involvement of the bony skeleton - elevated alkaline phosphatase- elevated alkaline phosphatase - CT - diffuse, bilateral, petrous bone involvement - CT - diffuse, bilateral, petrous bone involvement

with extensive de-mineralizationwith extensive de-mineralization

Differential diagnosisDifferential diagnosis

Osteogenesis imperfectOsteogenesis imperfect Vaen de hoeve syndromeVaen de hoeve syndrome

presence of blue sclerapresence of blue sclera multiple bone fracturesmultiple bone fractures

CT CT –– more common involves the otic capsule more common involves the otic capsule and to a greater extentand to a greater extent

Histologically can’t distinguish from Histologically can’t distinguish from otosclerosisotosclerosis

TreatmentTreatment

MedicalMedical No medical treatment that can cure this dsNo medical treatment that can cure this ds Controversies exist for the available options and Controversies exist for the available options and

generally not recommendedgenerally not recommended Sodium FluorideSodium Fluoride

Reduces osteoclastic resorption and increases osteoblastic Reduces osteoclastic resorption and increases osteoblastic bone formationbone formation

Dose – 50-70mg for 1-2 yearsDose – 50-70mg for 1-2 years IndicationsIndications

Non-surgical candidatesNon-surgical candidates Surgical candidates with + Schwartze’s signSurgical candidates with + Schwartze’s sign Cochlear otosclerosisCochlear otosclerosis

Disadvantage: fracture long bone and spineDisadvantage: fracture long bone and spine Contraindication: children, pregnant, chronic arthritis/nephritisContraindication: children, pregnant, chronic arthritis/nephritis

BisphosphonatesBisphosphonates Inhibits bone resorption by inhibiting Inhibits bone resorption by inhibiting

osteoclastic activity.osteoclastic activity. No effect on bone formationNo effect on bone formation Side effect: GI symptomsSide effect: GI symptoms

Hearing aidHearing aid For people with normal cochlear function and For people with normal cochlear function and

good speech discriminationgood speech discrimination

SurgicalSurgical Treatment of choice and 90% patient Treatment of choice and 90% patient

show good improvementshow good improvement

StepedectomyStepedectomy: removing the stapes bone : removing the stapes bone and replacing it with a micro prosthesis and replacing it with a micro prosthesis

StapedotomyStapedotomy: creating a small hole in the : creating a small hole in the fixed stapes footplate and inserting a tiny, fixed stapes footplate and inserting a tiny, piston-like prosthesis piston-like prosthesis

Best surgical candidateBest surgical candidate Air conduction level 30dB or worseAir conduction level 30dB or worse Bone conduction level 0 – 25 dBBone conduction level 0 – 25 dB Air-Bone Gap 15 dBAir-Bone Gap 15 dB Discrimination score >60%Discrimination score >60% Rhinne –ve for 256 and 512hzRhinne –ve for 256 and 512hz

Steps of surgerySteps of surgeryCanal InjectionCanal Injection

2-3 cc of 1% lidocaine 2-3 cc of 1% lidocaine with 1:50,000 or with 1:50,000 or 1:100,000 epinephrine1:100,000 epinephrine

4 quadrants4 quadrants

Bony cartilaginous Bony cartilaginous junctionjunction

Raise Tympanomeatal FlapRaise Tympanomeatal Flap

6 and 12 o’clock 6 and 12 o’clock positionspositions

6-8 mm lateral to the 6-8 mm lateral to the annulusannulus

Separation of chorda tympani nerve Separation of chorda tympani nerve from malleusfrom malleus

Separate the chorda Separate the chorda from the medial from the medial surface of the malleus surface of the malleus to gain slackto gain slack

Avoid stretching the n.Avoid stretching the n.

Curettage of ScutumCurettage of Scutum

Curettage a trough Curettage a trough lateral to the scutum, lateral to the scutum, thinning itthinning it

Then remove the Then remove the scutum (incus to the scutum (incus to the round window)round window)

Visualize the pyramidal Visualize the pyramidal process and facial n.process and facial n.

Total StapedectomyTotal Stapedectomy

UsesUses Extensive fixation of the footplateExtensive fixation of the footplate Floating footplateFloating footplate

DisadvantagesDisadvantages Increased post-op vestibular symptomsIncreased post-op vestibular symptoms More technically difficultMore technically difficult Increased potential for prosthesis migrationIncreased potential for prosthesis migration

Stapedotomy/Small FenestraStapedotomy/Small Fenestra

Originally for obliterated or solid footplatesOriginally for obliterated or solid footplates

AdvantagesAdvantagesLess trauma to the vestibuleLess trauma to the vestibuleLess incidence of prosthesis migrationLess incidence of prosthesis migrationLess fixation of prosthesis by scar tissueLess fixation of prosthesis by scar tissue

Drill FenestrationDrill Fenestration

0.7mm diamond burr0.7mm diamond burr Motion of the burr Motion of the burr

removes bone dustremoves bone dust Avoids smoke Avoids smoke

productionproduction Avoids surrounding heat Avoids surrounding heat

productionproduction

Laser FenestrationLaser Fenestration

LaserLaser Avoids manipulation of the footplateAvoids manipulation of the footplate Argon and Potassium titanyl phosphate (KTP/532)Argon and Potassium titanyl phosphate (KTP/532)

Wave length 500 nmWave length 500 nm Visible lightVisible light Absorbed by hemoglobin Absorbed by hemoglobin Surgical and aiming beamSurgical and aiming beam

Carbon dioxide (CO2)Carbon dioxide (CO2) 10,000 nm10,000 nm Not in visible light rangeNot in visible light range Surgical beam onlySurgical beam only

Requires separate laser for an aiming beam (red helium-neon)Requires separate laser for an aiming beam (red helium-neon) Ill defined fuzzy beamIll defined fuzzy beam

ContraindicationContraindication A - active/malignant otosclerosis A - active/malignant otosclerosis I - inner ear malformationI - inner ear malformation P - pregnancyP - pregnancy M - medically unfitM - medically unfit T - tympanic membrane perforationT - tympanic membrane perforation O - only hearing earO - only hearing ear O - otitis external/mediaO - otitis external/media O – occupation like athlete, divers, O – occupation like athlete, divers,

frequent air traveler, working in noisy frequent air traveler, working in noisy surroundingssurroundings

ComplicationsComplications Tear of tymanomeatal flap and Tm perforationTear of tymanomeatal flap and Tm perforation Injury to chorda tympani and taste disturbancesInjury to chorda tympani and taste disturbances Incus dislocationIncus dislocation VertigoVertigo Perilymph fistula/granulomaPerilymph fistula/granuloma Conductive loss due to short/long/displaced Conductive loss due to short/long/displaced

prosthesisprosthesis Sensorineural loss due to intraop Sensorineural loss due to intraop

trauma/labyrinthitistrauma/labyrinthitis Dead earDead ear

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