Surgical mx of otosclerosis

otology

1. Dr. SANJAY MAHARJAN PG, ENT – HNS MCOMS, Pokhara. Surgical treatment of otosclerosis

2. History : Surgery for otosclerosis has developed through three distinct eras: 1) The mobilization era 2) The fenestration era 3) The stapedectomy era

3. THE MOBILIZATION ERA: In 1842 , P rosper M eneire first reported mobilization of stapes In late 1800s , K essel attempted stapes mobilization without ossicular reconstruction In 1891 , J ack left oval window open after removing stapes Several french otolaryngologists performed mobilization of stapes, including Boucheron And Miot Adam Politzer , Siebenmann And Moure , declared that stapes surgery was useless, dangerous and unethical at 6 th international Otology Congress in London

4. THE FENESTRATION ERA : In 1897 , Passov suggested promontory fenestration In 1899 , Floderus suggested opening of vestibular labyrinth In 1913 , Jenkins in London described this as fenestration of lateral semicircular canal In 1920s , Nylen in Sweden was first to use microscope for ear surgery In 1923 , With advent of operating microscope , fenestration era began

5. Gunnar Holmgren (Father of fenestration surgery ); created fistula in lateral semicircular canal and sealed it immediately with periosteum Popularized during 1930’s by Sourdille in France (developed three stage technique) Julius Lempert in New York developed One-stage technique for horizontal semicircular canal fenestration

6. THE STAPEDECTOMY ERA: Started prior to end of fenestration era I n 1952 , Samuel Rosen from New York, tested mobility of stapes using transcanal approach before semicircular canal fenestration O n 1st May 1956 John Shea Jr ., i n collaboration with Treace , an engineer, created stapes prosthesis made of Teflon & used it for first time In 1960s , Plester suggested technique of partial stapedectomy in which only posterior third of foot plate was removed

7. In 1961 , the piston concept was introduced in which a cup or piston prosthesis was used with connective tissue graft of vein to seal oval window In 1962 , Shea et al and Marquet and Martin made small opening in middle of footplate into which prosthesis piston fitted exactly This initiated era of “ stapedotomy ” which has continued till present time Reverse Stapedotomy was popularized by Fisch and involved insertion of a prosthesis before removal of suprastructure of stapes

8. INDICATIONS : An air-bone gap of 25 dB or more at frequencies of 250 Hz to 1 kHz and a negative Rinne at 512 Hz are considered to be good indicators In cases of bilateral involvement, worse hearing ear is usually operated first

9. CONTRAINDICATIONS: ABSOLUTE CONTRAINDICATIONS: Only hearing ear Active middle ear or external ear infections When otosclerotic patient presents with symptoms of hydrops and has vertigo and tinnitus Severe middle ear atelectasis

10. RELATIVE CONTRAINDICATIONS: U nfit for GA When patient presents positive S chwartz sign Pregnancy Whose professional activities put them at risk, such as boxers, professional wrestlers, and those who indulge in severe physical strain

11. PREOPERATIVE COUNSELING : Should be informed about amplification as alternative mode for improved hearing Informed consent must include description of procedure and discussion of all potential risks:

12. Failure of procedure to correct conductive component of hearing loss Partial or complete SNHL (occurs in approximately 1% ) Vestibular disturbances Perforation of tympanic membrane Facial nerve injury Development of P erilymphatic fistula (PLF) Delayed failure after initial good result Disturbance of taste

13. OPERATIVE NOTE : The operative note must include: Shape and mobility of incus and malleus Presence of otosclerosis, fixation of stapes, patency of round window Location of and bone covering facial nerve Status of chorda tympani at end of procedure Unusual perilymphatic flow Type and size of prosthesis

14. ANESTHESIA : Choice of anesthesia depends on patient's and surgeon's preferences and nature of surgery planned A. Local anesthesia; saves time Intraoperative patient reports of vestibular stimulation may be used as safety measure to prevent excessive inner ear irritation B. General anesthesia; provides assurance against pain and head movement

15. SURGICAL TECHNIQUE: POSITIONING: Head turned towards contralateral shoulder and tilted downward 10 to 15 degrees

16. EXPOSURE AND EXPLORATION:

17. Transcanal approach Dotted line represents canal incision of tympanomeatal flap Flap is longer superiorly to cover scutectomy defect For flap to properly fold on itself exposing posterior superior quadrant it is best to carry incision slightly beyond malleus

18. Using twisting motion incision is created with circular knife Tunnel is created under the “vascular strip,”

19. Flap is raised to the level of tympanic annulus To avoid disturbance to ossicles middle ear is first entered inferiorly Bony prominence is often encountered slightly lateral to tympanic membrane level

20. Continuous pressure with knife against bony canal should be maintained T ympanic mucosa is lysed with a curved needle

21. Using back of annulus elevator, flap pushed against anterior canal wall where surface tension will adhere it

22. Elevation of annulus superiorly done with curved needle chorda tympani nerve identified and dissected free Elevation needs to be carried superiorly until flap is free from notch of R ivinus

23. Scutum has to be removed to provide full access to oval window D one with either a curette or microdrill or combination

24. Curette is firmly braced against speculum to create a fulcrum effect Motion is rotational and outward, inward leads to incus dislocation Considerable force is needed to fracture pieces of bone

25. Curetting is complete when facial nerve is in full view superiorly and junction of stapes tendon and pyramid are visible posteriorly

26. It is important to have sufficient room to bring instruments into action from superior, posterior, and inferior directions

27. Palpation of the stapes superstructure to confirm fixation

28. For sizing of prosthesis, measuring done from lateral aspect of incus to footplate To achieve proper angle, instrument shaft has to lean on anterior wall of speculum Correct measurement is between center and posterior third of footplate 4.5 mm in majority of cases

29. Slight outward pressure on incus with incudostapedial joint knife demonstrates thin gray line of joint Joint is cut with gentle “worming” motion in anterior direction gentle outward lifting of incus is best while strictly avoiding downward pressure on stapes capitulum

30. Stapedial muscle tendon divided using microscissors

31. Removal of stapes superstructure through down fracture toward promontory Should always be conducted away from facial nerve Curved needle should contact both crura , but preferentially apply force to anterior crus Excessive pressure on posterior crus will potentially lead to transverse footplate fracture

32. Creation of small fenestra stapedotomy with diamond burr Slightly larger than intended prosthesis ( eg : 0.7 mm for 0.6-mm piston) Quick, subtle inward drilling motion with goal of having burr penetrate to its meridian ( ie : widest point) and not beyond

33. Optimal position of fenestra is in posterior central region of footplate as vestibule is deepest in this region C ontact with footplate should be brief This procedure is delicate and potentially dangerous, a mere extra 1 mm of penetration can kill the ear

34. Using smooth alligator prosthesis is seated in position It is important to have both shepherd’s crook engage incus as well as the piston the fenestra If wire misses incus, piston can penetrate vestibule too deeply

35. Crimper must be stabilized on the wall of speculum Must be aligned perfectly with the wire

36. Once prosthesis is seated and crimped, its mobility is tested both by gently moving either incus or malleus handle Shallowly placed prosthesis will pop out when subjected to stress If this occurs, prosthesis is replaced with one 0.25 mm longer

37. TOTAL STAPEDECTOMY: In certain situations, stapedotomy is not possible and stapedectomy is performed Floating footplate Comminuted fracture of footplate Footplate inadvertently removed during suprastructure dislocation through anterior crus attachment Some revision surgeries When instruments required to create small fenestra are lacking

38. Gap between prosthesis and oval window opening to vestibule must be sealed with tissue graft, such as fat

39. STAPEDECTOMY VS STAPEDOTOMY :

40. LASERS IN OTOSCLEROSIS : Offer precision Avoids use of manual mechanical force Offer excellent hemostasis These qualities are desirable for: Fenestrating thin footplate with reduced risk of resultant floating footplate Having the ability to fenestrate mobile footplate Creating fenestra with minimal movement of footplate or perilymph

41. TYPES OF LASERS: Visible green light lasers (argon or potassium titanyl phosphate [ktp-532]) Invisible or infrared light lasers (Carbon Dioxide, CO2)

42. ADVANTAGES OF VISIBLE LASERS: Convenience of handheld probe for use of lasers during surgery Spot size can be chosen accurately DISADVANTAGES: The visible light lasers depend on char formation Char absorbs laser energy and creates heat The laser energy can pass through either directly or by scatter and injure neural tissue of utricle or saccule

43. ADVANTAGE OF CARBON DIOXIDE LASERS: Not absorbed in perilymph , thus potentially reducing risk to structures within vestibule DISADVANTAGES: Need for separate aiming beam Requirement of microscope-attached delivery system Recently, special flexible cable developed by OmniGuide allows CO2 laser beam to be precisely delivered through handheld probe

44. COMPLICATIONS OF LASERS:

45. TYPES OF PROSTHESIS : 1. Robinson prosthesis: Metal stem prosthesis designed to fit under lenticular process of incus Advantage  does not require crimping, relatively easy to insert Self-centering A narrow stem prosthesis is also available that can be used for posterior half footplate removal

46. 2. Causse prosthesis: Made of teflon and is designed to attach to long process of incus. Teflon ring is spread open and prosthesis is snapped onto incus Teflon has a long memory and does not require crimping Can be adjusted easily Can be used in small fenestra stapedectomy

47. 3. Fisch /McGee-type piston prosthesis: Consists of malleable ribbon-like crook connected to metal or teflon stem Crook is attached to long process of incus and must be crimped into position. Distal end of prosthesis is scored  checking exact length of prosthesis that is required easy Can be used in small fenestra stapedectomy .

48. 4. House wire prosthesis: One end is shepherd crook-like arrangement At other end is a loop Crook is attached and crimped to long process of the incus Technically more difficult to attach than other prostheses Used in total stapedectomy

49. POSTOPERATIVE CARE : Patients are instructed to keep their ears dry to avoid strenuous physical activities ( eg , heavy lifting, Valsalva maneuvers ) to avoid nose blowing , and to sneeze with an open mouth Air travel is permissible a couple of days after operation Oral antibiotics are continued for a week Audiometric evaluation is performed after 6 to 8 weeks

50. INTRAOPERATIVE COMPLICATIONS: A. TEARS IN TYMPANOMEATAL FLAP: Elevation of flap in limited segment E levating TM without annulus.

51. Repaired by placement of tragal perichondrium or fascia graft Underlay technique Small tears in vicinity of annulus  closed with piece of Gelfoam Small linear tears in canal skin flap  typically need no repair

52. B: SUBLUXATION OF THE INCUS: During curettage of bony annulus Separation of incudo-stapedial joint Manipulation around oval window Crimping If disarticulation or complete disruption of joint  best to remove incus and use malleus attachment prosthesis

53. C: OVERHANGING FACIAL NERVE: Can be dehiscent of its covering bone, but usually does not extend significantly out of fallopian canal If prolapsed nerve abuts the promontory inferior to oval window, surgery should not be completed Drilling small fenestra that includes the inferior aspect of the annular ligament Prosthesis must be longer than usual to accommodate bending inferiorly to avoid the nerve

54. D. OBLITERATIVE OTOSCLEROSIS:

55. Fenestration made by saucerizing the obliterated niche and thinning the obstructing bone After blue lining the vestibule, with a 0.7-mm diamond burr

56. E. PERSISTENT STAPEDIAL ARTERY: Incidence  1 of 5000 to 10,000 ears

57. It cannot be safely coagulated with bipolar cautery or laser Often occupies only anterior half of footplate and fenestration can be completed in the posterior half

58. F. PERILYMPH GUSHERS AND OOZERS: Incidence  0.03% Flow of cerebrospinal fluid Oozers  steady trickle of fluid, associated with persistent cochlear aqueduct Gusher  strong and forceful flow originating from defect in cribrose area of fundus of internal auditory canal Rapid drainage of inner ears fluids can threaten sensorineural hearing

59. Fenestra is packed with tissue graft or a cotton pledget Placing lumbar drain can be useful

60. G. FLOATING OR DEPRESSED FOOTPLATE: Footplate that is irretrievably depressed into vestibule will almost certainly cause vertigo Fenestration by laser reduces chances of footplate disarticulation Assessing movement of footplate before completing fracturing and disengaging suprastructure

61. H. OTOSCLEROSIS INVOLVING THE ROUND WINDOW: Attempts at removing this obstruction have resulted in SNHL Hence contraindicated

62. POSTOPERATIVE COMPLICATIONS: 1. PERILYMPH FISTULA: PLF Most common single complication of stapedectomy Potentially dangerous d/to risk of meningitis May give rise to dysequilibrium and hearing loss Types: Primary or early PLF Secondary or aquired PLF

63. A. PRIMARY OR EARLY PLF : Occurs when fistula created at time of surgery persists and fails to seal off vestibule Use of gelatin sponge ( gelfoam ) as a seal for oval window fenestra is associated with high incidence It may be resorbed before neomembrane has formed Gelatin sponge will get softened by perilymph and prosthesis will penetrate through it Neomembrane that forms with gelatin sponge is very thin Vein graft shows less incidence

64. SIGNS AND SYMPTOMS: Vary with size of leak Large fistulas  rapid hearing loss, tinnitus, and vertigo In early PLF when leak is small  hearing loss may initially appear as CdHL and then has sensorineural component and then progresses to total SnHL Minute fistula  failure of good closure of an air–bone gap, mild fluctuation in hearing, and small decrease in speech discrimination scores

65. B. SECONDARY OR AQUIRED FISTULA : Usually due to barotrauma , (flying , mountaineering, lifting heavy objects, coughing, sneezing, and head injury) which breaks fragile seal Characteristics symptom  change of hearing after successful operation; as/w fullness, tinnitus and dysequilibrium Can occur anytime after surgery

66. MANAGEMENT OF A PERILYMPH FISTULA: Surgical closure of fistula is treatment of choice Fistulous track is excised and prosthesis removed with great care Mucosa over footplate is elevated completely Fresh soft tissue seal is placed over adequately created fenestra New adequate prosthesis is placed over seal P atient is advised total rest in bed for 48 hours

67. 2. CHORDA TYMPANI DYSFUNCTION: Injury to nerve may result in Hypogeusia and dysgeusia Atrophy of fungiform papillae in denervated area Temporary symptoms, which will improve in course of 3 to 6 months

68. 3. FACIAL PALSY: Immediate facial paralysis is related to local anesthesia or intraoperative trauma to the nerve Can be damaged by Bone curette or drill during removal of bony annulus By fracturing stapes toward nerve rather than toward promontory By injuring anomalous nerve

69. 4. VERTIGO: Vertigo may appear during surgery, immediately following it, or in a delayed manner During surgery  insult to membranous labyrinth or may be result of air entering vestibule Pneumolabyrinth generally resolves in 24 to 48 h Blood causes chemical irritation and resolves in days Vertigo extending beyond that time suggests more serious insult to inner ear and is often associated with SNHL Delayed vertigo can be result of BPPV or PLF

70. 5. REPARATIVE GRANULOMA: Mass of exuberant granulation tissue developing in reaction to surgery, foreign body or to perilymph Manifests in 5th to 15th POD Symptoms and signs of labyrinthitis appear after an early period of hearing gain Otoscopy reveals edema, thickening, and hyperemia of skin flaps and tympanic membrane Immediate reexploration ; granulation tissue and prosthesis are removed, and fenestra is sealed with tissue graft Steroids may be useful

71. 6. SENSORINEURAL HEARING LOSS: Slight transient SnHL immediately  common occurrence and d/to mild serous labyrinthitis Permanent SNHL can occur immediately following surgery or appear weeks or months after Early loss, especially at high tones  surgical trauma Delayed SNHL  PLF Delayed fluctuating low-frequency loss  post-traumatic hydrops Up to 1% of patients suffer partial or even complete SNHL

72. 7. CONDUCTIVE HEARING LOSS: Can appear immediately or more commonly delayed after initial good result Common reasons for immediate conductive loss: (1) Malfunctioning prosthesis, eg : one that is too short (2) Unrecognized malleus fixation (3 ) Unrecognized round window obliteration (4 ) Middle ear effusion, and (5) Presence of unrecognized SSCD

73. CdHL after good initial closure or reduction of airbone gap Erosion of incus at site of prosthesis attachment (64%) Malpositioned prosthesis (41%) Bony (14%) or fibrous regrowth at oval window area Round window obliteration (23 %)

74. SUMMARY: Surgery for otosclerosis requires specific acquired skills Most common procedure to correct stapedial fixation is small fenestra stapedotomy with incus attachment prosthesis Successful surgery reduces air-bone gaps to less than 10 db and is achieved in 90% of patients Noteworthy complications include SNHL(1%), chorda tympani nerve dysfunction, and vestibular injury Revision surgery associated with lower success rates and slightly higher complication rates

75. REFERENCES: Shambaugh - Ear surgery 6th edn Scott – Browns otolaryngology 6 th edn De Souza – Otosclerosis Evolution of Stapes Surgery, P Karthikeyan , D Thomas