DR. SUDEEP K.C.

OTOSCLEROSIS

ANATOMY REVIEW: OTIC LABYRINTH OR MEMBRANOUS LABYRINTH

OR ENDOLYMPHATIC. PERIOTIC LABYRINTH OR PERILYMPHATIC

LABYRINTH – SURROUNDS THE OTIC LABYRINTH & IS FILLED WITH PERILYMPH.

OTIC CAPSULE – IT IS THE BONY LABYRINTH GOT THREE LAYERS ENDOSTEAL-THE INNERMOST LAYER. LINES THE

BONY LABYRINTH ENCHODRAL- DEVELOPS FROM THE CARTILAGE &

LATER OSSIFIES INTO BONE. PERIOSTEAL –COVERS THE BONY LABYRINTH.

AETIOLOGY

IDIOPATHIC SOME FACTS HAVE BEEN DOCUMENTED- ANATOMICAL BASIS –BONY LABYRINTH IS MADE

OF ENCHONDRAL BONE WHICH IS SUBJECT TO LITTLE CHANGE IN LIFE. BUT SOMETIMES , IN THIS HARD BONE THERE ARE AREAS OF CARTILAGE RESTS WHICH, DUE TO CERTAIN NON-SPECIFIC FACTORS, ARE ACTIVATED TO FORM NEW SPONGY BONE .

HERIDITY- 50% OF OTOSCLEROTICS HAVE POSITIVE FAMILY HISTORY

RACE – WHITE RACE ARE AFFECTED MORE THAN NEGROS. IT IS COMMON IN INDIANS BUT RARE AMONG CHINESE & JAPANESE

SEX- FEMALE 2 TIMES THAN MALE

AGE OF ONSET- DEFNESS USUALLY STARTS BETWEEN 20-30 YRS

EFFECT OF OTHER FACTORS- DEAFNESS DUE TO OTOSCLEROSIS MAY BE INITIATED OR MADE WORSE BY PREGNANCY , MENOPAUSE, ACCIDENT OR SURGERY

Types of Otosclerosis

1)Stapedial otosclerosis: It cause the fixation of stapes result in

conductive deafness . lesion starts just in front of oval window in an area called ‘fissula ante fenestram’. This is the site of predilection(ant. Focus).

2)Cochlear Otosclerosis: It involves region of round window or other

area in otic capsule, and may cause sensorineural hearing loss .

3)Histologic otosclerosis: This type of otosclerosis remains

asymptomatic and cause neither conductive nor sensorineural hearing loss.

Pathology:Grossly lesion appears chalky white, greyish or

yellow . sometimes red in colour due to increased vascularity.

Microscopically, there are numerous marrow and vascular spaces with plenty of osteoblast and osteoclasts that stains blue.

SYMPTOMS:

1)Hearing loss: Usually starts in twenties . Hearing loss is

painless and progressive with insidious onset . often it is bilateral conductive type.

2)Paracusis willisi: They hear better in noisy than quiet

surroundings . This is because a normal person will raise his voice in noisy surroundings.

3)Tinnitus : It is more seen in cochlear otosclerosis and in active lesion.

4)Vertigo: uncommon5) Speech: monotonous well modulated soft

speech.

SIGNS:a)TM is quite normal and mobile .Sometimes,a

reddish hue is seen on the promontory through tympanic membrane(Schwartze sign).Indicative of active focus with increased vascularity.

b)Eustachian tube function is normal.c)Tuning fork test show negative Rinne .d)Weber test will be lateralised to the ear with

greater conductive loss.

d)Pure tone audiometry shows loss of air conduction more for lower frequencies.

Bone conduction is normal . In some cases there is a dip in bone conduction curve maximum at 2000hz and is called the Carhart’s notch.

e) Stapedial reflex becomes absent when stapes is fixed.

TREATMENT:

a)Medical : sodium fluoride has been tried to hasten the maturity of active focus and arrest further cochlear loss.

b)Surgical: Stapedectomy with prosthesis replacement is the treatment of choice. laser STAMP

Selection of patients for stapes surgery:Hearing threshold should be 30db or more.Average air bone gap is 15 db with Rinne negative.

Laser STAMP (Laser Stapedotomy Minus Prosthesis)

In 1995, Dr. Silverstein developed a new technique called the Laser STAMP. The laser is used to free the frozen stapes bone in patients with minimal otosclerosis, preserving most of the patient's normal stapes bone. This restores the patient's hearing, without using a prosthesis. The advantages of preserving most of the patients' stapes include reduced sensitivity to noise, decreased incidence of noise damage to the ear, and reduced chance of trauma to the inner ear from changes in pressure during flying or diving.

Contraindications to stapes surgery:

1. The only hearing ear.2. Associated meniere’s disease.3. Young children.4. Professional athletes , high construction

workers, frequent air travellers.5. Those who work in noisy environment.

C) Hearing aid:

DIFFERENTIAL DIAGNOSIS

SHOULD BE DIFFERNTIATED FROM OTHER CAUSES OF CONDUCTIVE DEAFNESS PARTICULARLY – SEROUS OTITIS MEDIA ADHESIVE OTITIS MEDIA TYMPANOSCLEROSIS ATTIC FIXATION OF HEAD OF MALLEUS OSSICULAR DISCONTINUITY CONGENITAL STAPES FIXATION

THANK YOU

To be cont………….