OTOSCLEROSIS

OTOSCLEROSIS

1. OTOSCLEROSIS Dr Harjitpal Singh Assistant Professor(ENT), Dr RKGMC , Hamirpur

2. INTRODUCTION Disease of altered bone metabolism unique to the human temporal bone. Localized hereditary disorder affecting enchondral bone of the otic capsule characterised by disordered resorption and deposition of bone. Remodelled bone bridges the stapediovestibular joint  impedes sound transmission  Conductive hearing loss. Bone remodelling extends into the cochlea  Sensorineural hearing loss.

3. 6 Membranous Labyrinth

4. HISTORY VALSALVA – Early 18 th century – ankylosed stapes by ossification of it’s ligament Von Troltsch – In 1869 - Named the final inactive stage – Otosclerosis Siebenmann – In 1912 – Designated the active hyperemic stage “ Otospongiosis ” Politzer – Recognized otosclerosis as a primary bone disease

5. DEVELOPMENTAL ANATOMY LABYRINTH – 3 PARTS : MEMBRANOUS / OTIC / ENDOLYMPHATIC LABYRINTH : Utricle, saccule, cochlear duct ( scala media), semicircular ducts, endolymphatic duct and sac PERILYMPHATIC / PERIOTIC LABYRINTH : Vestibule, scala tympani, scala vestibule, perilymphatic spaces of semicircular and endolymphatic ducts BONY LABYRINTH / OTIC CAPSULE

6. DEVELOPMENTAL ANATOMY( cont ) OTIC CAPSULE : Ossifies by 14 ossification centres First centre – 16 weeks – region of cochlea Last centre – 20-21 weeks – posterolateral region of posterior semicircular canal Three layers of bone from ossified otic capsule : Outer periosteal layer Inner endosteal layer Enchondral layer – consisting of intrachondral and endochondral bone

7. PATHOGENESIS Normal otic capsule – low remodelling rate – 2% Otosclerosis – Abnormal bone remodelling in the endochondral layer GLOBULI INTEROSSEI – Embryonic cartilage rests – sites of predilection Immature bone laid – continued remodelling occurs – prominent osteoblastic involvement – OTOSPONGIOSIS Maturation of the lesion into a sclerotic, dense, irregularly woven and poorly vascularised bone - OTOSCLEROSIS

8. PATHOGENESIS( cont ) Most common site of predilection : FISSULA ANTE FENESTRUM – focus anterior to stapes footplate  Stapes fixation Other sites : Round window niche Cochlear apex Less frequently – walls of internal auditory canal, around cochlear aqueduct, semicircular canals

9. PATHOGENESIS ( cont ) GROSS APPEARANCE : Active, spongiotic lesions – rich vascularisation and hyperemic overlying mucosa  red discolouration of promontory  SCHWARTZE SIGN Mature focus of otosclerosis – white, well demarcated lesion

10. HISTOLOGY Immature active lesions – numerous vascular spaces with osteoblasts and precursors. Extracellular substance is increased – stains blue with hematoxylin -eosin stain  BLUE MANTLE – First histologic sign Mature lesions – Less vascular spaces, laying of more bone and fibrillar substance. Stains red with hematoxylin -eosin stain

11. ETIOLOGY GENETIC PREDISPOSITION : Autosomal dominant pattern with incomplete penetrance of 20 to 40 % 50% of cases – positive family history Eight loci associated with otosclerosis : OTSC1 – 8 Significant association with COL1A1 gene – codes for type I collagen VAN DER HOEVE syndrome : Triad of osteogenesis imperfecta (COL1A1 gene), otosclerosis and blue sclera

12. ETIOLOGY ( cont ) RACE : Whites more than blacks. Common in Indians. Rare amongst Chinese and Japanese SEX : More common in females. India – predominant in males AGE OF ONSET : Between 20 and 30 years. HORMONAL FACTORS : In females, deafness worsens during pregnancy and menopause

13. ETIOLOGY ( cont ) VIRAL INFECTION : Evidence of possible persistent measles infection. Ultrastructural and immunohistochemical evidence of measles like structures and antigenicity in active otosclerotic lesions Measles RNA in fresh footplate specimens of otosclerosis Elevated levels of antimeasles antibodies in the perilymph of patients undergoing stapedectomy

14. TYPES OF OTOSCLEROSIS STAPEDIAL : Causing stapes fixation and conductive hearing loss – most common COCHLEAR : Involves region of round window – liberation of toxins  Sensorineural hearing loss HISTOLOGIC : Remains asymptomatic

15. STAPEDIAL OTOSCLEROSIS ANTERIOR FOCUS : In front of the oval window – Fissula ante fenestra POSTERIOR FOCUS : Behind the oval window CIRCUMFERENTIAL : Around the margin of stapes footplate BISCUIT TYPE : In the footplate but annular ligament free OBLITERATIVE TYPE : Completely obliterates the oval window niche

16. STAPEDIAL OTOSCLEROSIS( cont )

17. COCHLEAR OTOSCLEROSIS It is defined as the presence of an otosclerotic lesion in the capsule of the cochlea , clinically characterised by sensorineural type of deafness probably due to liberation of toxic materials into the inner ear fluid . Cochlear otosclerosis involves region of round window or other areas in the otic capsule. It may be associated with stapedial fixation when it is known as combined or mixed otosclerosis. The diagnosis of pure cochlear otosclerosis without the involvement of stapes can be suspected in any patient who has developed bilateral progressive sensorineural deafness in early adult life.

18. HISTOLOGIC OTOSCLEROSIS This type of otosclerosis remains asymptomatic and causes neither conductive nor sensorineural hearing loss.

19. OTOSCLEROSIS - SYMPTOMS HEARING LOSS : Painless, progressive, often bilateral AGE : Patient presents in 3 rd or 4 th decade of life POSITIVE FAMILY HISTORY of hearing loss PARACUSIS WILLISI : Patient hears better in noisy surroundings TINNITUS : More common in cochlear type VESTIBULAR SYMPTOMS : 10 – 30% of the patients. Dizziness, unsteadiness – potential coexistence of otosclerosis and Meniere’s disease

20. OTOSCLEROSIS - SIGNS OTOSCOPY : Normal mobile tympanic membrane. (2% of patients with chronic otitis media – may have otosclerosis – additive component) SCHWARTZE SIGN : Vascular blush on the promontory seen through the tympanic membrane TUNING FORK TESTS : 256, 512, 1024 Hz Rinne – Negative Weber – Lateralised to the ear with greater conductive loss Absolute Bone Conduction – May be normal. Reduced in cochlear type

21. AUDIOLOGICAL EVALUATION PURE TONE AUDIOMETRY TYMPANOMETRY ACOUSTIC REFLEX

22. PURE TONE AUDIOMETRY Complete audiometry – air and bone conduction thresholds, speech discrimination scores – essential Characterizes the severity of the disease Shows loss of air conduction, more for lower frequencies. Conductive, mixed or rarely pure sensorineural hearing loss may be present Maximal conductive loss – 55 to 60 dB Conductive loss > 60 dB – suspicion of ossicular discontinuity

23. PURE TONE AUDIOMETRY ( cont ) Depression of bone conduction threshold at 2000 Hz – CARHART’S NOTCH-- It disappears after successful stapedectomy . Decrease in bone conduction thresholds: 5 dB at 500 Hz 10 dB at 1000 Hz 15 dB at 2000 Hz 5 dB at 4000 Hz

24. AIR – BONE GAP : Early in the disease , typical air-bone gap greatest in the lower frequencies More advanced ankylosis – loss equalizes across frequencies

25. TYMPANOMETRY Normal in early cases. Curve of ossicular stiffness – As – later

26. ACOUSTIC REFLEX

27. 24 ACOUSTIC REFLEX ( cont ) Measure of movement of stapes at stimulus Reflex is absent in otosclerosis Progressive changes in the configuration of the acoustic reflex with stapedial fixation : A:- Healthy reflex with a sustained change in compliance as long as stimulus is on . B:- Diphasic reflex with on-off pattern. Seen in cases of early otosclerotic fixation . C:- Absent acoustic reflex

28. DIFFERENTIAL DIAGNOSIS Ossicular discontinuity Congenital stapes fixation Attic fixation of malleus head Paget’s disease Serous otitis media Osteogenesis imperfecta

29. TREATMENT NON SURGICAL : Sodium fluoride : Was believed to slow the progression of the disease. No evidence to support use of sodium fluoride in otosclerosis Hearing aids . SURGICAL : Stapedectomy Stapedotomy Stapes mobilization Lempert’s fenestration operation STAPES SURGERY

30. SURGERY FOR OTOSCLEROSIS INDICATIONS : Air-bone gap of 25 dB or more at frequencies of 250 Hz to 1000 Hz Rinne negative at 512 Hz Speech discrimination minimum 60% Bilateral involvement – Worse ear operated first. Patient preference in case of symmetric loss

31. SURGERY FOR OTOSCLEROSIS ( cont ) CONTRAINDICATIONS: Infected middle ear or external ear Perforation of the tympanic membrane Active disease Only hearing ear Patients with vestibular symptoms – to rule out Meniere’s disease Professions requiring intact vestibular system – Athletes, divers, frequent fliers Industrial workers – work in noisy surroundings – vulnerable to occupational sensorineural hearing loss Pregnancy

32. SURGERY FOR OTOSCLEROSIS ( cont ) ANAESTHESIA: Patient’s and surgeon’s preference LOCAL ANAESTHESIA : Saves time Intra-operative vestibular stimulation: patient can report & prevents excessive inner ear irritation GENERAL ANAESTHESIA : Assurance against pain and head movement No increased risk of vestibular stimulation

33. SURGERY FOR OTOSCLEROSIS ( cont ) 1.Permeatal incision is made from the 6 O’clock to 12 O’clock position , 6 mm lateral to the tympanic annulus at the centre . The tympanomeatal flap is elevated 2. Exposure of stapes area. This may require removal of posterosuperior bony overhang of the canal. 3 . Removal of stapes superstructure. 4 . Creation of a hole in the stapes footplate ( stapedotomy ) or removal of a part of footplate ( stapedectomy ). 5 . Placement of prosthesis. 6 . Repositioning the tympanomeatal flap.

34. PROSTHESIS

35. PROSTHESIS ( cont ) Correct length of the prosthesis is the measured distance of the medial side of the incus to the opening in the footplate plus 0.25 mm An additional 0.25 mm is added – if bending of prosthesis is anticipated Ascertain sufficient opening of the loop of the prosthesis Prosthesis grasped by its loop with alligator forceps and placed on the incus and fenestra in one movement Tightening of the loop around the incus done with a crimper – at the narrowest area of the long process

36. TOTAL STAPEDECTOMY Performed in certain situations : Floating footplate Comminuted fracture of the footplate Footplate inadvertently removed during suprastructure dislocation through anterior crus attachment Revision surgeries Instruments required to create a small fenestra are lacking

37. COMPARISON STAPEDECTOMY Better low frequency hearing gain Maybe the only method technically possible STAPEDOTOMY Better high frequency hearing gain Lower incidence of : Perilymph fistula SNHL Lateralization of graft Postoperative vertigo Less labyrinthine trauma

38. SURGERY FOR OTOSCLEROSIS( cont ) Stapes mobilization: It is no longer done these days as it gives temporary results; refixation being quite common Lempert’s fenestration operation: It is almost outdated now. Here an alternative window is created in the lateral semicircular canal to function for the obliterated oval window . It has the disadvantage of a postoperative mastoid cavity and an inherent hearing loss of 25 dB which cannot be corrected .

39. POST-OPERATIVE CARE Can be discharged few hours after the surgery with instructions : Keep the ear dry Avoid strenuous physical activities Avoid nose blowing ; Sneeze with an open mouth Air travel permissible after a couple of days Oral antibiotics continued for a week

40. COMPLICATIONS INTRAOPERATIVE : TEARS IN THE TYMPANOMEATAL FLAP : Repaired by placement of a medially placed tragal perichondrium or fascia graft SUBLUXATION OF INCUS : Complete procedure with incus attachment prosthesis Abort and give time for the incus to reattach to the malleus Complete disarticulation – remove incus and use malleus attachment prosthesis

41. COMPLICATIONS ( cont ) OTOSCLEROSIS OF THE ROUND WINDOW : Complete obliteration associated with conductive hearing loss. Attempts at removing  Sensorineural hearing loss – hence contraindicated OBLITERATIVE OTOSCLEROSIS OF OVAL WINDOW : Saucerizing the obliterated niche and thinning the obstructing bone. Fenestration made with a 0.7 mm diamond burr PERSISTENT STAPEDIAL ARTERY : Incidence – 1 in 5000 to 10000 ears. Occupies anterior half of the footplate – fenestration in posterior half. Cannot be safely coagulated with bipolar cautery or laser.

42. COMPLICATIONS ( cont ) MALLEUS ANKYLOSIS : Corrected by removing the incus and head of malleus and reconstruction with malleus attachment prosthesis PERILYMPH GUSHERS AND OOZERS : Rapid drainage of inner ear fluids  sensorineural hearing loss Fenestra is packed with tissue graft, vein graft or perichondrium Preoperative lumbar drain placement and lowering cerebrospinal fluid pressure – in suspected cases

43. COMPLICATIONS ( cont ) FLOATING / DEPRESSED FOOTPLATE : Fenestration may be made with laser A small bur hole created inferior to the annular ligament and the footplate elevated with a small hook Opening sealed with a tissue graft and appropriately sized prosthesis placed If footplate is depressed into the vestibule, should not be extracted

44. COMPLICATIONS( cont ) Exposed, overhanging Facial Nerve FACIAL PALSY : Immediate : Local anaesthesia, intraoperative trauma to nerve Delayed : Incidence 0.5%. Appears 5 to 20 days after surgery and resolves within 1 or 2 months CHORDA TYMPANI DYSFUNCTION : Injury – hypoguesia and dysguesia ; atrophy of fungiform papillae in the denervated area A stretched nerve causes more disturbing symptoms than a severed nerve

45. COMPLICATIONS ( cont ) OTITIS MEDIA : In immediate postoperative period : High risk of suppurative labyrinthitis and meningitis. Treatment : Removal of ear canal packing Admission and broad spectrum antibiotics Steroids to minimize inner ear damage

46. COMPLICATIONS ( cont ) VERTIGO : During surgery, immediate post – op or delayed onset Immediate : Insult to membranous labyrinth, pneumolabyrinth , chemical irritation by blood Delayed : Benign paroxysmal positional vertigo, perilymphatic fistula

47. COMPLICATIONS ( cont ) REPARATIVE GRANULOMA : Mass of exuberant granulation tissue developing in reaction to surgery or foreign body 5 th to 15 th day of surgery – signs and symptoms of labyrinthitis Otoscopy : Oedema and hyperemia of skin flaps and tympanic membrane Audiometry : Mixed hearing loss and decreased speech discrimination Immediate re-exploration – granulation tissue and prosthesis removed, fenestra sealed with tissue graft. Post-op steroids.

48. COMPLICATIONS ( cont ) PERILYMPHATIC FISTULA : PRIMARY : At the end of stapedectomy SECONDARY : Develops months or years later Rates significantly lower following stapedotomy Symptoms : Persistent or fluctuating hearing impairment, vertigo and disequilibrium, aural fullness, meningitis Positive fistula test Treatment : Re-exploration and defect closure

49. COMPLICATIONS ( cont ) SENSORINEURAL HEARING LOSS : Early : Surgical trauma Delayed : Perilymphatic fistula

50. COMPLICATIONS ( cont ) CONDUCTIVE HEARING LOSS : IMMEDIATE : Malfunctioning prosthesis Unrecognized malleus fixation Unrecognized round window obliteration Middle ear effusion Unrecognized semicircular canal dehiscence

51. COMPLICATIONS ( cont ) CONDUCTIVE HEARING LOSS : DELAYED : Erosion of the incus at site of prosthesis attachment Malpositioned prosthesis Bony or fibrous regrowth at the oval window area Round window obliteration

52. REVISION STAPES SURGERY More challenging Higher incidence of complications Lower success rates

53. INDICATIONS Immediate or delayed postoperative conductive hearing loss of atleast 20 dB in speech frequencies Dizziness and unsteadiness – Excessively long prosthesis Symptoms of perilymphatic fistula

54. FINDINGS AT REVISION EXPLORATION Prosthesis malfunction at the incus Prosthesis displacement from the oval window Intact footplate Short prosthesis Malleus fixation Laser helpful in revision surgeries – Divide adhesions, mucosal folds, soft tissue surrounding the prosthesis in oval window

55. THANKs