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Stapedotomy

last modified on: Fri, 02/23/2024 - 15:14

return to: Otology - Neurotology

GENERAL CONSIDERATIONS

  1. Indications
    1. Reversal of conductive hearing loss caused by a fixed stapes footplate
  2. Contraindications
    1. General medical condition of the patient
      1. Cannot lay flat
      2. Cannot tolerate anesthesia
      3. Blood thinners
    2. If the diseased ear is the only hearing ear
    3. Patients in whom vestibular function is absolutely critical to their livelihood
    4. Presence of Meniere's disease (aural fullness, vertigo, tinnitus, fluctuating HL)
      1. Endolymphatic hydrops can make the saccule dilated. This dilation can be great enough that the saccule can be pressed against the undersurface of the footplate. Entrance into the footplate can pierce the saccule, which could result in profound SNHL in the patient.
    5. Pt with poor cochlear reserve (severe SNHL or poor speech discrimination scores)
    6. Presence of active middle ear infection or tympanic membrane perforation
    7. Relative contraindication: multiple revisions without benefit

PREOPERATIVE PREPARATION

  1. Evaluation
    1. History
      1. Patients present complaining of gradual hearing loss, may be asymmetric
        1. May complain of having difficulty hearing conversation while eating
        2. May actually hear better in noisy environments (Paracusis of Willis).
      2. 2/3 of patients are female. Anecdotal evidence for disease to progress while associated with pregnancy, so hearing loss may become apparent in the years after childbirth.
      3. 70% of patients have bilateral disease.
      4. Strong family history of hearing loss.
        1. Autosomal dominant disease with variable penetrance.
      5. Patients usually have a negative history for trauma or infection as the cause for their conductive hearing loss
      6. Pediatric patient
        1. Congenital conductive deafness. Usually without tinnitus or vertigo.
    2. Physical Exam
      1. Otomicroscopy
        1. Pneumatic otoscopy should be performed to rule out perforation or effusion as the cause for their conductive hearing loss.
        2. Look for malleus movement as well.
        3. Schwartze’s sign: Red blush on the promontory, usually anterior to the oval window, indicative of the increased blood flow in the otic bone during the otospongiosis phase of the disease.
      2. Tuning forks
        1. Weber and Rinne exams tested bilaterally with 256, 512 and 1024 Hz tuning forks.
        2. Surgery is offered when at least two tuning forks are negative on the Rinne test.
      3. Always document facial nerve exam.
    3. Audiology
      1. Patient should have a mixed or conductive hearing loss
      2. Complete audiometric testing
        1. Pure tone averages are measured to determine air conduction, bone conduction. Special attention to masking with possible masking dilemmas.
        2. Speech thresholds and discrimination.
        3. Carhart’s notch. Downward deflection of the bone curve at between 1000-4000 Hz, usually at 2000 Hz.
      3. Tympanometry: performed to determine other sources of conductive hearing loss such as effusion, perforation, tympanosclerosis
      4. Acoustic Reflex:
        1. Usually by the time the patient seeks medical attention, the acoustic reflex is gone.
        2. In the early phase of the disease, a momentary "on-off" reflex will be seen at the beginning and the end of the given stimulus.
        3. Positive early deflection is pathognomonic for otosclerosis.
    4. Temporal Bone CT Scan
      1. When considering stapedectomy on a child or someone with congenital stapes fixation.
      2. X-linked perilymph gusher syndrome:
        1. Congenital conductive or mixed hearing loss featuring enlarged vestibular aqueduct.
        2. Stapes surgery is contra-indicated, because of likelihood of perilymphatic gusher.
      3. To rule-out superior semi-circular canal dehiscence in patients with normal acoustic reflex
  2. Consent
    1. Purpose of procedure
      1. Improve hearing
    2. Alternatives
      1. Amplify hearing with a hearing aid
      2. Observation
    3. Expected outcomes
      1. Closure of air bone gap within 10-15 dB in 95% of patients for first attempt
        1. Revision results are worse: 85% or so to improve within 15 dB
      2. This surgery is not expected to reverse tinnitus
  3. Possible Risks:
    1. Failure of prosthesis
    2. Temporary or permanent alteration in taste from injury to chorda tympani nerve: 30%
    3. Injury to the facial nerve (exceedingly rare, may be delayed in onset)
    4. Tympanic Membrane perforation
    5. Possible transient dizziness, rare permanent dizziness
    6. Sensorineural hearing loss (very rare, approximately 0.2% chance of deafness)
  4. Although the case is listed as "stapedectomy", the diagnosis of stapes fixation is presumed. Definitive diagnosis cannot be made until the ossicular chain is examined.

NURSING CONSIDERATIONS

  1. Basic Otology Setup (Room and Instruments)

ANESTHETIC CONSIDERATIONS

  1. Our preferred approach is MAC anesthesia
    1. Goal: No pain, low blood pressure, but the patient alert enough to follow instructions, answer questions, and can verbalize vertigo
    2. We prefer a small dose of versed, then sedation/analgesia with propofol/fentanyl
    3. Consider general:
      1. Claustrophobic
      2. Previous bad/paroxysmal reactions to MAC
      3. Pediatric
      4. Consider in non-English speaking patients, as you will not be able to communicate with them during surgery.
    4. If no anesthesia personnel present, may do under local anesthesia with nursing administration of
      1. 2-4 mg Versed in titrated doses
      2. 25-50mg Demerol
      3. 25 mg Phenergan or Vistaril.
  2. Preoperative Systemic Medications:
    1. see otology antibiotic administration protocol
    2. 10 mg Decadron. (Hold if the patient is diabetic)
  3. Positioning: see general considerations for otologic surgery

OPERATIVE PROCEDURE

  1. The choice of prosthesis is beyond the scope of this discussion. Surgeons should use the prosthesis with which they are most-comfortable, and which has given good results in their hands.
  2. After prepping and draping, inject postauricular crease with 1% lidocaine with epinephrine 1:100,000
    1. suggest bolus of propofol during all injections
  3. Fit largest speculum as possible into EAC, at least a size 5.
  4. Microscope (already draped) is brought in and the ear canal is then injected with 1cc or less of 2% lidocaine with epinephrine 1:20,000.
    1. Do not over-inject as this makes the flap thick and cumbersome.
    2. Inject slowly: no blebs!
  5. Flap elevation
    1. An incision is made into the skin of the ear canal using either a McCabe flap knife or a Rosen round knife. Begin the incision inferiorly at approximately 6 o’clock to 12 o’clock. The flap is then raised.
      1. Make flap approximately 6 mm in length. McCabe is 6 mm in length.
        1. The flap needs to be long enough to reach the EAC after removing some of the scutum
      2. Raise flap with McCabe knife and 20 suction.
        1. Do not suction on flap
      3. At annulus, do not lift! Enter in middle ear space first.
        1. Once flap is raised, enter cautiously into middle ear space.
      4. Chorda tympani will be seen by annular groove. Do not disrupt.
  6. Exposure
    1. Curet scutum
      1. Variable amount of bone needs to be removed to visualize footplate.
        1. Suggest ’I’ curette
        2. Vector of force should be inferior and lateral
        3. Do not injure chorda
        4. Do not dislocate incus
      2. Goal: visualize all structures.
        1. Entire ossicular chain including malleus
        2. Stapedial tendon/pyramidal eminence
        3. Facial nerve
        4. round window
        5. Entire oval window/footplate
  7. Assess ossicular mobility
    1. Palpate malleus and watch for round window reflex and mobility of entire ossicular chain.
    2. Palpate incus and stapes individually as well
    3. If the entire ossicular chain is mobile, abort the case and obtain temporal bone CT to rule out superior semicircular canal dehiscence.
  8. Stapedotomy
    1. Different techniques exist for stapedectomy versus stapedotomy and pros and cons of each are beyond the scope of this discussion. We use the following technique of stapedOTOMY.
    2. Diode laser
      1. 1000 milliWatts set at 0.1 second duration for footplate work and 1600milliWatts at 0.2 for suprastructure work.
      2. Sever the stapedial tendon and the posterior crus (and anterior crus if it’s accessible).
    3. Use laser to create a rosette of lasered bone on the footplate.
    4. If the footplate bone is too thick, a microdrill is used to create the aperture.
      1. Suggest Skeeter microdrill, 0.8mm bit.
  9. A 0.1mm right angle hook is used to laterally deflect flecks of bone away from the footplate.
  10. A Farrior rasp is used to widen the surgically created aperture until it is large enough to accommodate the base of the piston.
    1. Standard piston: 0.6 mm diameter, 4.25 mm length
  11. Place piston into stapedotomy, and position crozet over the incus.
    1. For SmART prosthesis, use laser to crimp prosthesis
      1. Avoid thermal damage to incus
    2. Manual crimping if necessary
  12. AFTER securing stapedectomy
    1. Release the incudostapedial joint with a 2mm right-angle hook or tab knife - force is directed exactly opposite stapedial tendon.
    2. Downfracture the stapes with the right-angle hook.
    3. After downfracture, alligator forceps are used to remove the stapes superstructure.
  13. Scratch promontory to form a blood patch over the stapedotomy.
  14. Check hearing
    1. Lower the TM flap
    2. Lighten the patient’s anesthesia
    3. Whisper Spondee words. Ask patients to repeat.
  15. Closure
    1. No packing is placed in the middle ear.
    2. 2-3 pieces of saline-soaked Gelfoam are placed along the edges of the TM flap to maintain its position.
    3. Place cotton ball in EAC meatus

      Grace Eclipse Piston in place - 4.25 mm x 0.6 mm
  16. Intraoperative Complications/Issues
    1. Tympanic membrane perforation
      1. Assess ossicular mobility to confirm diagnosis
      2. Graft TM
      3. Close and re-schedule stapedectomy after complete healing of TM
    2. Overhanging facial nerve
      1. Abort surgery and close TM flap
    3. Ossicular mobility intact (no stapes fixation)
      1. Abort surgery and close TM flap
    4. Persistent stapedial artery
      1. May require abortion of surgery
    5. Incudal dislocation
      1. Reposition and fix with bone cement
      2. Remove incus and place TORP in stapedotomy
        1. Place TORP atop tissue graft
      3. Reposition, close without completing stapedectomy, and return to OR after several months
    6. Incudal fixation and mobile stapes
      1. Remove incus
      2. Ossiclar reconstruction
        1. PORP
        2. Incus interposition
    7. Malleal fixation
      1. Nip malleus head with guillotine-style malleus head nippers
      2. PORP versus incus interposition
    8. Biscuit footplate
      1. Drill out footplate with 0.5 mm Skeeter drill
      2. Objective is to blue-line footplate, finish job with pick and Farrior rasp
    9. Vertigo during surgery (Perilymph fistula)
      1. Tissue seal
        1. Fascia graft
        2. Vein graft
        3. Perichondrium
        4. Blood seal

POST-OPERATIVE CARE

  1. Disposition
    1. Patient may be admitted for overnight observation after laying flat for 6 hours (BJG).
    2. Alternately, the patient may be allowed to discharge to home the same day, depending on surgeon preference (MRH).
  2. H2O precautions
    1. Patient is instructed to keep ear dry until follow-up in one month
    2. Cotton ball covered in petroleum jelly for showering.
  3. Activity restrictions x 3 weeks
    1. Pressure changes
      1. nose blowing
      2. air travel
      3. SCUBA diving
      4. sneeze with mouth open
  4. Begin use of eardrops (non-aminoglycoside eardrops) on post-op day 1. Use twice daily every day until follow up.
  5. Follow-up
    1. At one month.
      1. Clean ear
      2. Check TM mobility
      3. Document facial nerve exam
      4. Document tuning forks: all three frequencies!
      5. Audiograms not typically obtained at one month postop
    2. At 3-4 months after surgery
      1. Full audiometry
    3. Consider scheduling second side surgery six months after first stapedotomy

REFERENCES

Hannley MT: Audiologic characteristics of the patient with Otosclerosis. ''Otolaryngol Clin North Am'' 1993; 26:373.

Brown KD, Gantz BJ. Hearing results after stapedotomy with a nitinol piston prosthesis . Otolaryngol Head Neck Surg. 2007 Aug;133(8):758-62.

Gantz BJ, Jenkins HA, Kishimoto S, Fisch U. Argon laser stapedotomy Ann Otol Rhinol Laryngol. 1982 Jan-Feb;91(1 Pt 1):25-6.

House HP, Hansen MR, Al Dakhail AA, House JW. Stapedectomy versus stapedotomy: comparison of results with long-term follow-up Laryngoscope. 2002 Nov;112(11):2046-50.

Ealy M, Chen W, Ryu GY, Yoon JG, Welling DB, Hansen M, Madan A, Smith RJ. Gene expression analysis of human otosclerotic stapedial footplates. Hear Res. 2008 Jun;240(1-2):80-6. Epub 2008 Mar 15.