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STAPEDOTOMY — A COMPREHENSIVE DISCUSSION

(RGUHS 50-Mark Long Essay)

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INTRODUCTION

• 1956 — John Shea Jr.: First stapedectomy (total footplate removal + Teflon piston)
• 1960s — Small fenestra stapedotomy introduced by Fisch, Marquet, and House
• 1970s–1980s — Laser stapedotomy (CO₂ and argon lasers)
• 2000s onwards — Endoscopic stapes surgery; shape-memory (nitinol) prostheses

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SECTION 1 — ANATOMY RELEVANT TO STAPEDOTOMY

The Stapes

• Smallest ossicle; resembles a stirrup
• Head → articulates with incus (lenticular process)
• Neck → stapedius tendon inserts posteriorly
• Anterior and posterior crura → support the footplate
• Footplate → sits in the oval window; ~3 × 1.4 mm
• Movements: piston-like (primary), rocking, twisting

Critical Surgical Landmarks

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SECTION 2 — OTOSCLEROSIS (Background for Indication)

• Progressive conductive hearing loss (CHL)
• Normal tympanogram (Type A or Type As — shallow peak)
• Absent acoustic reflexes (or early diphasic/biphasic reflex — Carhart notch)
• Carhart's notch — apparent bone-conduction dip at 2000 Hz (mechanical, not sensorineural — corrects post-surgery)
• Negative Rinne with 512 Hz tuning fork

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SECTION 3 — INDICATIONS FOR STAPEDOTOMY

Absolute Indications (KJ Lee / Cummings)

1. Air-bone gap (ABG) ≥ 25–30 dB — sufficient to produce a negative Rinne test with the 512 Hz tuning fork
2. Normal otoscopic examination — no active otitis media, no perforation
3. Acoustic reflex absent or biphasic (confirms stapedial fixation)
4. Unilateral or bilateral otosclerosis — always operate on the worse-hearing ear first
5. Patient is medically fit for surgery and willing to accept the risks

Additional Supporting Criteria (Dhingra / Scott-Brown)

• Bone conduction ≥ 15 dB (to ensure functional cochlea)
• Negative Rinne at 256 and 512 Hz
• Schwartze sign (flamingo pink tympanic membrane) may be present — indicates active otosclerosis; surgery still possible
• Patient preference after discussion of all alternatives

Contraindications

"We never operate on the better or only hearing ear." — Cummings Otolaryngology, Ch. 146

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SECTION 4 — PRE-OPERATIVE PREPARATION

4A. Clinical Assessment

• Full ENT examination including otoscopy, tuning fork tests (Rinne, Weber, ABC)
• Examination for Schwartze sign
• Rule out other causes of CHL (glue ear, ossicular discontinuity, tympanosclerosis)

4B. Audiological Workup

• Pure tone audiogram (PTA): Air and bone conduction — document ABG
• Speech audiogram: Speech discrimination score (should be good)
• Tympanometry: Type A or As
• Acoustic reflexes: Absent or biphasic (Carhart notch verified)
• DPOAE / TEOAE: To document inner ear status

4C. Radiological Workup

• HRCT temporal bone: Not routine but indicated when:
  • Obliterative otosclerosis suspected
  • Revision surgery
  • Congenital ossicular anomaly suspected
  • X-linked stapes gusher syndrome (large endolymphatic duct → perilymph gusher on footplate opening)
• CT findings in otosclerosis:
  • Lucency at fissula ante fenestram (early)
  • Halo sign around cochlea (cochlear otosclerosis)
  • Dense sclerotic bone around otic capsule (late)

4D. Anaesthesia Planning

• Local anaesthesia (LA) + IV sedation (MAC): Preferred by most otologists
  • Midazolam 0.5–2 mg IV; supplemented with morphine 2–4 mg if needed
  • Advantage: Awake patient reports vertigo; confirms hearing improvement intraoperatively
  • 4-quadrant canal block + vascular strip: 1% or 2% lidocaine with 1:100,000 epinephrine
• General anaesthesia (GA): Preferred in teaching hospitals, paediatric cases, anxious patients

Caution: Infiltration of LA must not reach the middle ear cavity — can cause temporary facial palsy (from contact with dehiscent facial nerve) or violent vertigo (from labyrinthine diffusion through oval or round windows). — KJ Lee's Otolaryngology

4E. Patient Counselling (Informed Consent)

• SNHL < 2%; total deafness ~0.2%
• Transient dizziness (1 in 20)
• Taste disturbance (1 in 3): usually temporary
• Tinnitus changes
• Tympanic membrane perforation
• Failure to improve hearing (need for revision surgery ~1%)
• Facial nerve palsy (rare — < 0.1%)
• Perilymph fistula

4F. Pre-operative Orders

• No antiplatelet drugs for 7–10 days pre-operatively
• Pre-op audiogram baseline documented
• Hair over post-auricular area shaved (if approach requires)
• NBM from midnight (for GA cases)
• Review for medical fitness (HTN, DM, anticoagulants)

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SECTION 5 — SURGICAL TECHNIQUE OF STAPEDOTOMY

5A. Instruments Required

• Operating microscope (or 0° rigid endoscope for endoscopic approach)
• Sickle knife (No.1), House canal knife (No.2), annulus elevator (gimmick)
• Curettes (House, Hough)
• Stapes pick, joint knife, malleus head holder
• Measuring rod (Saunders) or prosthesis measuring hook
• Microdrill with 0.7 mm diamond bur (or laser — CO₂ / KTP / argon)
• Alligator or Hartmann forceps for prosthesis
• McGee crimper / laser (for nitinol prostheses)

5B. Prostheses Available

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BOX 146.1 — STAPEDOTOMY OPERATIVE PROCEDURE

STEP 1  → Canal injections: 4-quadrant + vascular strip (1% lidocaine + 1:100,000 epinephrine)
STEP 2  → Create tympanomeatal flap incisions; elevate flap; enter middle ear beneath annulus;
           free chorda tympani from adhesions under tympanic membrane
STEP 3  → Remove bone from posterosuperior canal wall (curette or microdrill) to ensure
           visibility of facial nerve and pyramidal process
STEP 4  → Palpate ossicular chain to confirm stapes fixation
STEP 5  → Measure distance from lateral surface of incus to footplate
STEP 6  → Use laser to make rosette in center of footplate
STEP 7  → Use microdrill with 0.7 mm diamond bur to weaken posterior crus and create fenestra
STEP 8  → Place piston prosthesis into fenestra and onto incus
STEP 9  → Crimp prosthesis hook (or use laser for nitinol prostheses)
STEP 10 → Down-fracture stapes superstructure and remove
STEP 11 → Place tissue graft or blood around prosthesis to form seal

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5C. Detailed Step-by-Step Description

• Sickle knife incision: from the lateral process of malleus inferiorly to the lower fourth of the canal (~8 mm lateral to annulus)
• Connected laterally using a House canal knife
• Flap elevated evenly lateral to medial using a canal elevator / round knife
• Annulus elevated from its bony canal with the annulus elevator ("gimmick")
• Chorda tympani identified and preserved
• Superior elevation carried to the malleus handle

• Posterosuperior bony overhang curetted with a House curette
• Enough bone removed to visualize: facial nerve, pyramidal process, stapes, and oval window fully
• Posterior half of annular ring of tympanic membrane freed

• Palpation of malleus and incus confirms they are mobile
• Stapes is found to be fixed (confirms otosclerosis)
• Identify: facial nerve, stapedius tendon, posterior crus, footplate

• Measured from the medial surface of the incus long process to the footplate surface using a calibrated measuring rod (usually 4.25–4.5 mm; prosthesis should extend 0.5 mm beyond the footplate into the vestibule)

• Stapedius tendon cut with scissors or laser near the pyramidal process

• A joint knife separates the lenticular process of incus from the head of stapes
• Gentle, to avoid dislocating the incus

• Laser method (preferred): CO₂, KTP, or argon laser creates a rosette pattern in the center of the footplate, then a 0.6–0.8 mm fenestra
• Manual method (Perforator / Drill): 0.7 mm microdrill with a diamond bur; Skeeter microdrill widely used
• Fenestra positioned anterior to center or center of footplate
• Avoid suctioning perilymph (causes vestibular disturbance)

• Piston inserted through the fenestra (0.5 mm beyond footplate into vestibule)
• Loop placed over the long process of incus
• Alligator crimper used to crimp the loop onto the incus (or laser for nitinol — self-crimping with heat)
• Verify mobility by gently pushing the malleus — drum moves if prosthesis properly seated

• After prosthesis is secured, stapes superstructure is fractured anteriorly and removed using a pick
• (In the "reverse stapedotomy" technique — Fisch — prosthesis placed first, then superstructure removed — reduces risk of floating footplate)

• Small pledget of fat, fascia, blood clot, or perichondrium placed around the piston at the oval window to seal the fenestra
• Prevents perilymph fistula; stabilizes prosthesis

• Tympanomeatal flap returned to its original position
• External auditory canal packed with absorbable gelfoam or merocel
• No skin sutures needed (endaural / transcanal approach)

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5D. FLOWCHART — STAPEDOTOMY SURGICAL SEQUENCE

DIAGNOSIS OF OTOSCLEROSIS
        │
        ▼
INDICATIONS CONFIRMED (ABG ≥ 25-30 dB, -ve Rinne, absent reflex)
        │
        ▼
PRE-OP WORKUP (PTA, tympanometry, CT if needed, counselling)
        │
        ▼
ANAESTHESIA (LA + MAC preferred)
        │
        ▼
TRANSCANAL APPROACH
        │
        ▼
TYMPANOMEATAL FLAP ELEVATION
        │
        ▼
SCUTAL CURETTAGE (posterosuperior canal wall)
        │
        ▼
MIDDLE EAR EXPLORATION
(confirm stapes fixation; identify facial nerve, chorda tympani)
        │
        ▼
MEASURE PROSTHESIS LENGTH
(incus to footplate + 0.5 mm)
        │
        ▼
STAPEDIUS TENDON DIVISION
        │
        ▼
INCUDOSTAPEDIAL JOINT SEPARATION
        │
        ▼
FENESTRA IN FOOTPLATE
(Laser: CO₂/KTP/argon  OR  Microdrill: 0.6-0.8 mm)
        │
        ▼
PROSTHESIS INSERTION & CRIMPING
(Teflon/Titanium/Nitinol piston)
        │
        ▼
DOWN-FRACTURE & REMOVAL OF STAPES SUPERSTRUCTURE
        │
        ▼
FAT/FASCIA SEAL AROUND PISTON AT OVAL WINDOW
        │
        ▼
TYMPANOMEATAL FLAP REPLACEMENT + CANAL PACKING
        │
        ▼
POST-OP CARE & AUDIOLOGICAL FOLLOW-UP

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SECTION 6 — STAPEDECTOMY vs STAPEDOTOMY

"With the use of small fenestra techniques, fistula is rarely seen as a cause of failure in stapes surgery." — Cummings, Ch. 146

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SECTION 7 — COMPLICATIONS OF STAPEDOTOMY

7A. Intraoperative Complications

7B. Early Post-operative Complications

7C. Delayed / Long-term Complications

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FLOWCHART — MANAGEMENT OF POST-OPERATIVE HEARING FAILURE

POOR HEARING AFTER STAPEDOTOMY
        │
        ▼
PTA + TYMPANOGRAM + CT TEMPORAL BONE
        │
   ┌────┴────┐
   ▼         ▼
EARLY        DELAYED
(≤6 wk)     (>6 wk)
   │              │
Reparative    Recurrent CHL
Granuloma?  ──► Prosthesis displaced?
Fistula?    ──► Incus necrosis?
Serous        ──► Malleus/incus fixation?
Labyrinthitis?
   │
   ▼
RE-EXPLORATION
± Prosthesis revision
± Fascia graft
± Granuloma removal

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SECTION 8 — SPECIAL SITUATIONS

8A. Paediatric Stapedotomy (Cummings)

• Performed in congenital stapes fixation or juvenile otosclerosis
• Higher risk of general anaesthesia complications
• Excellent hearing outcomes comparable to adults
• Increased risk of needing revision due to growth

8B. Revision Stapedotomy

• Causes: short/displaced prosthesis, incus necrosis, granuloma, re-fixation
• More technically challenging; SNHL risk higher than primary
• Wire-piston exchange most common revision; incus reconstruction may be needed

8C. Obliterative Otosclerosis

• Footplate cannot be identified; oval window covered by bone
• Requires careful drilling; risk of cochlear damage
• Hearing aid or cochlear implant may be preferable

8D. Osteogenesis Imperfecta (Van der Hoeve syndrome)

• Associated CHL from stapes fixation
• Blue sclerae, CHL, bone fragility (triad)
• Higher surgical risk: brittle incus (fracture during crimping), tympanic ring fracture
• Good functional outcomes possible with care (KJ Lee)

8E. Endoscopic Stapedotomy (Recent Advance)

• Transcanal endoscopic ear surgery (TEES) using 0° or 45° rigid endoscopes
• Advantages: No scutal curettage needed; wide field of view; less invasive
• Comparable hearing outcomes to microscopic approach
• Learning curve; single-handed technique
• Published by Presutti, Marchioni, Tarabichi (Cummings)

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SECTION 9 — RECENT ADVANCES

9A. Laser Stapedotomy

• CO₂ laser: Most precise; no acoustic trauma; non-contact — "thermally cuts" footplate
• KTP (532 nm) laser: Via micromanipulator or fiber; good haemostasis
• Diode laser: Fiber-based; versatile
• Advantage over drill: No mechanical trauma to inner ear; controlled fenestra; reduced vertigo

9B. Shape-Memory (Nitinol) Prostheses

• Self-crimping when heated by laser — no mechanical crimping forceps required
• Reduced trauma to incus long process during crimping
• SMART prosthesis (Shape Memory Alloy with Redundant Technology) — precise incus coupling

9C. Endoscopic Stapes Surgery (TEES)

• Avoids post-auricular incisions; no canal curettage needed
• Better visualisation of anterior footplate
• Comparable audiological outcomes; shorter hospital stay

9D. Robotic-Assisted Stapedotomy

• Early experimental: micro-robotics (RobOtol) to create precise fenestrations
• Reduces hand tremor; highly reproducible fenestra size

9E. Intraoperative Monitoring

• Intraoperative ABR (auditory brainstem response) monitoring
• Electrocochleography — real-time cochlear function monitoring

9F. Cochlear Implantation in Far-advanced Otosclerosis

• When CHL is unresponsive to surgery + significant sensorineural component
• Peri-cochlear otosclerosis can reduce electrode insertion; drilling required

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SECTION 10 — FLOWCHART: MANAGEMENT OF CONDUCTIVE HEARING LOSS (OTOSCLEROSIS)

PATIENT WITH PROGRESSIVE CHL
         │
         ▼
CLINICAL EVALUATION
(History, Otoscopy, Tuning forks)
         │
         ▼
AUDIOLOGICAL ASSESSMENT
(PTA, ABG, Tympanometry, Acoustic reflexes)
         │
     ┌───┴───┐
     ▼       ▼
ABG ≥25 dB  ABG < 25 dB
Fixed stapes  Mild disease
     │            │
     ▼            ▼
SURGICAL      HEARING AID +
CANDIDATE?    OBSERVATION
     │
  ┌──┴──┐
  ▼     ▼
FIT   UNFIT / REFUSES
  │         │
  ▼         ▼
STAPEDOTOMY  HEARING AID
(Preferred)   or BAHA
  │
  ▼
POST-OP AUDIOGRAM
(≥ 6 weeks)
  │
  ▼
HEARING IMPROVED?
  │          │
 YES         NO
  │           │
  ▼           ▼
DISCHARGE  EVALUATE FOR
FOLLOW-UP  COMPLICATIONS /
           REVISION SURGERY

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INTRAOPERATIVE CLINICAL IMAGES

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SECTION 11 — POST-OPERATIVE CARE

1. Day 0–1: Bed rest; head elevation; antiemetics for nausea/vertigo
2. Antibiotics: 5–7 days (amoxicillin-clavulanate or ciprofloxacin drops)
3. Avoid: Nose blowing, Valsalva, heavy lifting, straining for 2–3 weeks
4. Canal pack removal: 1–2 weeks
5. Audiogram: At 6–8 weeks post-op (baseline ABG reassessment)
6. Flying: Avoid for 3–4 weeks minimum
7. Return to work: Usually 1 week (desk work); longer for physical work
8. Follow-up: 6 weeks, 3 months, 1 year

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SECTION 12 — HEARING OUTCOMES

"Total SNHL occurs in about 0.2% of cases." — Cummings, Ch. 146

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SUMMARY TABLE — STAPEDOTOMY AT A GLANCE

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REFERENCES

1. Cummings Otolaryngology Head and Neck Surgery (7th Ed.) — Chapter 146: Otosclerosis. John W. House, Calhoun D. Cunningham III.
2. KJ Lee's Essential Otolaryngology (12th Ed.) — Chapter on Stapedectomy and Ossicular Reconstruction.
3. Scott-Brown's Otorhinolaryngology, Head and Neck Surgery (8th Ed.) — Volume on Otology; Chapter on Otosclerosis.
4. Diseases of Ear, Nose and Throat — PL Dhingra (7th Ed.) — Otosclerosis and Stapes Surgery.
5. Hazarika P. — Textbook of ENT and Head & Neck Surgery — Otosclerosis.
6. Stell and Maran's Head and Neck Surgery — Relevant otologic principles.
7. Fisch U: Stapedotomy versus stapedectomy. Am J Otol 1982.
8. Marchioni D, et al.: Endoscopic transcanal stapedotomy. Otolaryngol Head Neck Surg 2014.
9. Lesinski SG: Lasers for otosclerosis — CO₂ vs. KTP-532. Laryngoscope 1989.
10. Goh BS, et al.: Nitinol prostheses in stapedotomy. Otol Neurotol 2010.

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