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OSSICULOPLASTY

A Comprehensive 50-Mark Answer

As per RGUHS Syllabus | References: Scott-Brown, Cummings, Stell & Maran, Zakir Hussain, Dhingra, Hazarika & Recent Literature

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1. DEFINITION

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2. HISTORICAL BACKGROUND

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3. ANATOMY OF THE OSSICULAR CHAIN (Relevant to Ossiculoplasty)

SOUND WAVES → Tympanic Membrane
                    ↓
              MALLEUS (Handle/Manubrium)
                    ↓ (incudomalleolar joint)
              INCUS (Body → Long Process → Lenticular Process)
                    ↓ (incudostapedial joint)
              STAPES (Head → Neck → Crura → Footplate)
                    ↓
              OVAL WINDOW → Perilymph → Cochlea

Sound Transmission Mechanism:

• The ossicular chain acts as an impedance-matching transformer between air (low impedance) and fluid medium of inner ear (high impedance)
• Gain = 25–30 dB through:
  • Hydraulic ratio (TM area: footplate area = 17:1) → ×17 pressure gain
  • Lever ratio of ossicular chain = 1.3:1
  • Total effective gain: ~25 dB

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4. INDICATIONS FOR OSSICULOPLASTY

Primary Indications:

1. Chronic Otitis Media (COM) – mucosal type with ossicular erosion
2. Cholesteatoma – with ossicular destruction (Bailey & Love, 28th ed., p. 779)
3. Traumatic ossicular disruption – incudostapedial dislocation, stapes fracture
4. Congenital ossicular anomalies – absent/fused ossicles
5. Tympanosclerosis – fixation of ossicles
6. Osteogenesis imperfecta (Van der Hoeve syndrome)
7. Post-myringoplasty hearing rehabilitation

Prerequisites:

• Air-bone gap (ABG) ≥ 20 dB with conductive/mixed loss
• Patent Eustachian tube function
• No active infection (dry ear for ≥6 weeks)
• Adequate cochlear reserve (SRT/SDS)
• No sensorineural component (> 30 dB SNHL is relative contraindication)

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5. PREOPERATIVE EVALUATION

Audiological Assessment:

PTA (Pure Tone Audiometry)
├── AC threshold (Air Conduction)
├── BC threshold (Bone Conduction)
└── Air-Bone Gap (ABG) calculation

TYMPANOMETRY
├── Type A: Normal (As = stapes fixation; Ad = ossicular disruption)
├── Type B: Flat (middle ear fluid)
└── Type C: Negative pressure (ETD)

SPEECH AUDIOMETRY
├── SRT (Speech Reception Threshold)
└── SDS (Speech Discrimination Score)

Radiological:

• HRCT Temporal Bone (1mm cuts): Ossicular erosion, footplate status, tegmen, sinus plate, labyrinthine fistula

Nasal/ETF Assessment:

• Siegle's speculum test / Valsalva
• Impedance audiometry (type C → poor prognosis)

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6. CLASSIFICATION OF OSSICULAR DEFECTS

Austin-Kartush Classification (Most Widely Used)

Bellucci Classification:

• Class I: Dry ear, no infection
• Class II: Minimal infection, controlled
• Class III: Active infection
• Class IV: Wet ear, active disease

Simplified Classification by Ossicular Status:

OSSICULAR DEFECT
│
├── MALLEUS PRESENT
│   ├── Stapes present → Type A (best prognosis)
│   └── Stapes absent → Type B
│
└── MALLEUS ABSENT
    ├── Stapes present → Type C
    └── Stapes absent → Type D (worst prognosis)

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7. PROSTHESIS TYPES

A. Based on Extent of Replacement:

B. Based on Material:

3D CBCT Image of Titanium PORP in situ:

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8. SURGICAL TECHNIQUES

FLOWCHART: Surgical Decision Algorithm

PATIENT WITH CONDUCTIVE HEARING LOSS
            │
            ▼
    PREOPERATIVE WORKUP
    (PTA, HRCT, ETF assessment)
            │
            ▼
    IS EAR DRY? DISEASE CONTROLLED?
       │                    │
      YES                   NO
       │                    │
       ▼                  Treat infection first / Stage surgery
    OSSICULOPLASTY        ──────────────────────────────
    PLANNING                     │
       │                         ▼
       ▼                  STAGED OSSICULOPLASTY
  INTRAOPERATIVE          (2nd stage after 6-12 months)
  ASSESSMENT
       │
  ┌────┴────┐
  │         │
STAPES   STAPES
PRESENT  ABSENT
  │         │
PORP       TORP
  │         │
  └────┬────┘
       │
       ▼
CARTILAGE INTERPOSITION?
(if thin TM or risk of extrusion)
       │
      YES → Cartilage cap on prosthesis
       │
       ▼
   HEARING RESULT ASSESSMENT
   (ABG < 20 dB = SUCCESS)

A. TYMPANOPLASTY + OSSICULOPLASTY (Combined)

Step-by-step Technique:

• GA preferred; LA with sedation possible
• Head turned 30° to opposite side
• Patient supine

• Endaural (Rosen/Lempert incision) – limited access
• Postauricular (most common) – wide exposure
• Transcanal – suitable for anterior pathology

• Incisions at 6 and 12 o'clock positions
• Elevate skin + TM as single flap
• Enter middle ear via posterior canal wall

• Assess ossicular chain:
  • Mobility of malleus handle
  • Integrity of incus long process
  • Incudostapedial joint
  • Stapes superstructure and footplate mobility

Type A (Malleus + Stapes both present – intact chain):

• Minimal intervention; may need incus interposition if only incus missing

Malleus Handle
      ↓
 Incus (sculpted/interposition)
      ↓
 Stapes Head

Type B (Incus absent, stapes superstructure present – PORP):

Tympanic Membrane / Malleus
            ↓
         [PORP]
            ↓
      Stapes Head

• PORP height ~2.5 mm (variable)
• Cartilage cap placed between TM and prosthesis to prevent extrusion

Type C (Malleus absent, stapes present):

• PORP placed directly under TM onto stapes head
• Cartilage graft essential

Type D (Total absence – TORP):

Tympanic Membrane
        ↓
     [TORP]
        ↓
  Stapes Footplate

• TORP height ~4.5–5.5 mm
• High extrusion rate – cartilage interposition mandatory
• Worst hearing results

• Temporalis fascia (most common) – underlay technique
• Perichondrium – better for retraction pockets
• Cartilage – for high-risk cases

• Gelfoam in middle ear
• Tympanomeatal flap repositioned
• Canal packing
• Postauricular closure (if used)

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9. AUTOLOGOUS INCUS TRANSPOSITION TECHNIQUES

Austin's Incus Interposition:

• Incus sculpted to form a strut
• Placed between malleus handle and stapes head
• Best hearing results with autologous material

Methods of Shaping the Incus:

• Body + short process used as autograft
• Long process removed and reshaped
• Joint surfaces curetted for better coupling

Columella Effect:

• Sound transmission via a single strut (natural or prosthetic) from TM to oval window
• Named after the columella in frog ear
• Principle behind all ossiculoplasty

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10. SPECIAL SITUATIONS

A. Stapes Fixation (Tympanosclerosis):

• Type As tympanogram
• Surgery: Mobilization or stapedectomy/stapedotomy + PORP/TORP
• Plaque around stapes must be carefully removed

B. Fixed Malleus:

• Anterior epitympanic adhesion
• Chipping away of bony overhang required
• If unreachable → ossicular chain interruption + TORP preferred

C. Congenital Ossicular Anomalies:

• Fused malleoincudal complex
• Absent stapes superstructure
• Better cochlear reserve but technically difficult
• CT essential pre-op

D. Oval Window Obliteration:

• TORP placement on fibrous/bony obliteration
• Drill-out of niche or laser fenestration
• High sensorineural risk

E. Tympanosclerosis:

TYMPANOSCLEROSIS
        │
   ┌────┴────┐
   │         │
TM only   Middle ear plaques
   │         │
Myringoplasty  Ossicular chain assessment
              │
         ┌───┴───┐
         │       │
    Removable  Fixed
         │       │
    Remove +  Chain interruption
    Ossiculoplasty + TORP/PORP

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11. STAGED OSSICULOPLASTY

When is it staged?

1. Active cholesteatoma
2. Wet/infected ear
3. Poor mucosal status
4. Canal wall down mastoidectomy

Staging Protocol:

• Stage 1: Disease eradication (mastoidectomy ± tympanoplasty)
• Wait: 6–12 months for mucosal healing
• Stage 2: Ossiculoplasty ± canal wall reconstruction
• Silastic sheeting placed in Stage 1 to prevent adhesions

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12. ENDOSCOPIC OSSICULOPLASTY

Advantages over Microscopic:

• No postauricular incision
• Better visualization of anterior middle ear, hypotympanum
• Reduced manipulation of canal skin
• Improved visualization of Eustachian tube orifice, round window niche
• Single-handed technique limitation (offset by better visualization)

Technique:

• 0° and 45° endoscopes (3mm or 4mm)
• Transcanal endoscopic ear surgery (TEES)
• Ossiculoplasty via exclusively endoscopic transcanal approach
• Increasingly popular since 2010s

Limitations:

• Single-handed surgery (lack of bimanual dexterity)
• No depth perception
• Learning curve
• Thermal injury risk from light source

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13. HEARING RESULTS – EXPECTED OUTCOMES

Success Criteria:

• ABG ≤ 20 dB = Surgical success (most accepted standard)
• ABG ≤ 10 dB = Excellent result

Results by Prosthesis Type:

Factors Affecting Prognosis:

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14. COMPLICATIONS

Intraoperative:

1. Perilymph fistula – penetration of stapedial footplate
2. Sensorineural hearing loss (SNHL) – inner ear trauma
3. Facial nerve injury – aberrant nerve course, especially in congenital anomalies
4. Chorda tympani injury – taste disturbance, dry mouth
5. Bleeding – jugular bulb, carotid artery
6. Labyrinthine fistula (cholesteatoma cases)

Early Postoperative:

1. Infection – otitis media
2. TM perforation – graft failure
3. Vertigo – inner ear irritation
4. Facial palsy – edema/trauma
5. Hemotympanum

Late Postoperative:

1. Prosthesis extrusion (most common late complication)
   • Highest with TORP (10–15%)
   • Reduced by cartilage cap
2. Prosthesis displacement/migration
3. Recurrent/residual cholesteatoma
4. Re-erosion of ossicles
5. Adhesive otitis
6. Tympanosclerosis of graft
7. Retraction pocket

Management of Extrusion:

PROSTHESIS EXTRUSION
        │
        ▼
  Tympanic membrane perforation/thin area
        │
  ┌─────┴─────┐
  │           │
Small       Large
Perforation  Perforation
  │           │
Observe /   Revision Surgery
Cartilage     │
tympanoplasty ▼
           Remove prosthesis
           Cartilage + new prosthesis
           or Staged approach

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15. SPECIFIC SCENARIOS IN RGUHS CONTEXT

Dhingra's Classification of Tympanoplasty (Wullstein):

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16. BIOMECHANICS OF OSSICULOPLASTY

Lever Mechanism:

Malleus arm : Incus arm = 1.3 : 1

Hydraulic ratio:
TM effective area : Footplate area
= 55 mm² : 3.2 mm²
= 17 : 1

Total gain = 17 × 1.3 = ~22× pressure amplification
= ~27 dB

After Ossiculoplasty:

• Rigid prostheses (titanium, HA) preserve acoustic impedance better
• Flexible prostheses (cartilage) absorb some energy – slightly reduced gain
• Optimal prosthesis height critical – too long or short reduces coupling

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17. MATERIALS: ADVANTAGES AND DISADVANTAGES (Detailed)

Titanium Prostheses (Current Gold Standard):

• Weight: Ultra-light (0.008 g for PORP)
• MRI: Safe (non-ferromagnetic)
• Design: Multiple designs (Kurz, Gyrus-ACMI, Heinz Kurz)
• Biocompatibility: Excellent – no toxic/allergic reactions
• Osseointegration: Some surface bonding
• Extrusion rate: ~5–8% PORP, ~10–12% TORP at 5 years

Hydroxyapatite:

• Natural bone mineral component (Ca₁₀(PO₄)₆(OH)₂)
• Osteoconductive but not osteoinductive
• Bonds to existing bone
• Brittle – can fracture with minor trauma

Autologous Incus:

• Best biocompatibility (own tissue)
• Readily available from surgical field
• Remodelled to shape
• May resorb over time if blood supply disrupted
• Not available in cholesteatoma (may be destroyed)

Cartilage:

• Tragal or conchal
• Perichondrium included for vitality
• Very low extrusion – used routinely as cap
• Shape memory – difficult to fashion precisely

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18. RECENT ADVANCES IN OSSICULOPLASTY

1. Endoscopic Ossiculoplasty (TEES):

• Transcanal Endoscopic Ear Surgery
• Minimally invasive, no postauricular scar
• Publications: Marchioni (2015), Tarabichi (2014), Preyer (2018)
• Comparable hearing results to microscopic

2. Robotic-Assisted Surgery:

• Still experimental
• Reduces tremor in microsurgical manipulation
• Future direction

3. Bioactive Glass (Bioglass 45S5):

• Bonds to both bone and soft tissue
• S53P4 bioglass used in Europe (Bonalive®)
• Shows promising results in chronic ear surgery

4. 3D-Printed Custom Prostheses:

• CT-based patient-specific prostheses
• Titanium or PEEK material
• Custom fit = better acoustic coupling
• Still research phase (Fayad et al., 2019)

5. Injectable Hydrogel / Tissue Engineering:

• Scaffold-based cartilage regeneration
• Growth factors (TGF-β) for ossicular regeneration
• Experimental

6. Active Middle Ear Implants (AMEI):

• Vibrant Soundbridge (Medel)
• Floating Mass Transducer (FMT) on round window or PORP
• For mixed/sensorineural hearing loss
• Excellent results where conventional ossiculoplasty fails

7. Laser-Assisted Ossiculoplasty:

• CO₂ laser / Er:YAG laser
• Precise cutting of tympanosclerotic plaques
• Laser stapedotomy for footplate fenestration

8. Otoendoscopy + Image Guidance:

• Navigation systems for complex revision cases
• Intraoperative CT for verification

9. Intraoperative Monitoring:

• Electromyographic facial nerve monitoring
• Cochlear microphonic monitoring (experimental)

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19. POSTOPERATIVE CARE

Immediate (0–48 hours):

• Head elevation (30°)
• Avoid nose blowing
• Analgesics, antibiotics (broad spectrum)
• Ear packing: Gelfoam + BIPP/ribbon gauze

Short-term (1–6 weeks):

• Packing removal at 1–2 weeks (canal pack)
• Assess TM healing at 4–6 weeks
• Audiogram at 6–8 weeks
• Water precautions continued

Long-term Follow-up:

• PTA at 3 months, 6 months, 1 year
• Monitor for extrusion
• Monitor for recurrence (cholesteatoma)
• HRCT at 1 year (staged cases)

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20. MASTER FLOWCHART: COMPLETE OSSICULOPLASTY PATHWAY

PRESENTING COMPLAINT: HEARING LOSS ± EAR DISCHARGE
                    │
                    ▼
             CLINICAL ASSESSMENT
             H/O + ENT Examination
                    │
                    ▼
            PURE TONE AUDIOGRAM
          (Conductive/Mixed Loss?)
                    │
               ABG ≥ 20 dB?
               /           \
             YES             NO → Non-surgical options
               │
               ▼
         TYMPANOGRAM
         HRCT Temporal Bone
         ETF Assessment
               │
               ▼
      DISEASE ACTIVITY ASSESSMENT
           /          \
         DRY          WET
          │             │
          │           TREAT + WAIT 6 weeks
          │             │
          └──────┬───────┘
                 │
                 ▼
         SURGICAL PLANNING
                 │
      INTRAOPERATIVE FINDINGS
                 │
    ┌────────────┼────────────┐
    │            │            │
OSSICLES      PARTIAL       TOTAL
INTACT         LOSS          LOSS
    │            │            │
  Type A      Type B/C      Type D
    │            │            │
Possible     PORP /        TORP /
incus        Autograft     Columella
interposition
    │            │            │
    └────────────┴────────────┘
                 │
           CARTILAGE CAP?
                 │
            TYMPANOPLASTY
         (Temporalis Fascia/Cartilage)
                 │
                 ▼
         STAGED OR PRIMARY?
         /              \
      PRIMARY          STAGED
      (dry ear,         (cholesteatoma,
       good mucosa)      active disease)
                 │
                 ▼
         POSTOPERATIVE CARE
                 │
         AUDIOGRAM at 6-8 wks
                 │
           ABG ≤ 20 dB?
           /         \
         YES           NO
          │             │
       SUCCESS       Review:
                    Extrusion?
                    Displacement?
                    Cholesteatoma?
                         │
                    REVISION SURGERY

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21. EXAMINATION SUMMARY TABLE (RGUHS Focus)

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REFERENCES

1. Scott-Brown's Otorhinolaryngology, Head and Neck Surgery, 8th Edition, Vol. 3 – Ear
2. Cummings Otolaryngology – Head and Neck Surgery, 7th Edition, Flint et al.
3. Stell and Maran's Head and Neck Surgery, 5th Edition
4. Diseases of Ear, Nose and Throat – PL Dhingra, 7th Edition, pp. 78–90
5. Hazarika's Textbook of ENT Head & Neck Surgery, 3rd Edition
6. Bailey and Love's Short Practice of Surgery, 28th Edition, p. 779
7. Zakir Hussain – ENT for Undergraduate Students
8. Wullstein HL – Theory and practice of tympanoplasty, Laryngoscope, 1956
9. Austin DF – Ossicular reconstruction, Arch Otolaryngol, 1971
10. Marchioni D et al. – Endoscopic ossiculoplasty, Otolaryngol Head Neck Surg, 2015
11. Tarabichi M et al. – Transcanal endoscopic ear surgery, Laryngoscope, 2014
12. Fayad JN et al. – 3D-printed titanium prostheses, Otol Neurotol, 2019
13. Quesnel AM, Nadol JB – Tympanoplasty and ossiculoplasty long-term outcomes, Otolaryngol Clin North Am, 2013
14. Yung M – Ossiculoplasty with titanium prostheses, Laryngoscope, 2003
15. Triglia JM et al. – Ossicular reconstruction outcomes, J Int Adv Otol, 2021

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RGUHS Examination Tip: For a 50-mark answer, always include: Definition + Historical evolution + Anatomy + Classification + Types of prostheses + Surgical technique (step by step) + Complications + Recent advances. Use the Austin-Kartush classification, Wullstein classification, and draw the PORP/TORP diagrams clearly. Examiners specifically look for mention of staged ossiculoplasty, cartilage interposition, and titanium vs. autologous graft comparison.