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ENT
Ossicular Chain Reconstruction
Built from Haynes-Glasscock-Shambaugh Surgery of the Ear, Seventh Edition
What’s inside
13 sections · 114 slides
Aims and determinants of outcome
- Goals of ossicular chain reconstruction
- Hierarchy of factors influencing results
- Value of preoperative risk stratification
Types of ossicular reconstruction
- Origin of the tympanoplasty classification
- Type I tympanoplasty
- Type II tympanoplasty
- Type III tympanoplasty
- Subtypes of type III tympanoplasty
- Stapes columella subtype
- Minor columella subtype
- Major columella subtype
- Type IV tympanoplasty
- Type V tympanoplasty
Preoperative assessment
- Components of the preoperative evaluation
- Reconciling audiogram with tuning fork tests
- Audiometric clues to underlying pathology
- Eustachian tube evaluation
- General rules of surgical candidacy
- Exceptions to the candidacy rules
- Age as a prognostic factor
- Timing of paediatric tympanoplasty
Qualities of the prosthesis
- Materials used in ossicular implants
- Hydroxylapatite versus titanium
- Prosthesis weight
- Limitations of laboratory prosthesis studies
- PORP and TORP: definitions and structure
- Stability of prosthesis designs
Middle ear acoustic mechanics
- Two pathways of inner ear stimulation
- Impedance mismatch and its correction
- The acoustic transformer theory
- Hydraulic lever effect
- Malleoincudal and catenary levers
- Limitations of the transformer model
- Acoustic coupling
- Phase and round window shielding
- Applying mechanisms of gain to technique
Incus erosion
- Pathogenesis of incus long process erosion
- Intraoperative assessment of the eroded incus
- Reconstruction options for incus erosion
- Advantages and drawbacks of type II repair
- Anatomical relationships for minor columella
- Rotation of the malleus about its anchoring axis
- Extreme malleus displacement
- Selecting and sizing a PORP
- Measurement error and failed reconstruction
- Contour of the prosthesis to the malleus handle
- Bending the prosthesis to the conical drum
- Freestanding reconstruction and packing
- Cartilage cap and prevention of extrusion
- Cartilage reconstruction of the drum
Incus and stapes superstructure absent
- Options when the superstructure is absent
- TORP dimensions and orientation
- Instability at the footplate
- TORP with a footplate shoe for a rotated stapes
- Rotated or at-risk stapes superstructure
Malleus absent
- Problem of the absent manubrium
- Single-stage reconstruction without a malleus
- Length errors and delayed lateralisation
- Staged ossiculoplasty via the facial recess
- Perichondrium-cartilage island graft as a pseudo-malleus
- Constructing the pseudo-malleus graft
- Positioning the pseudo-malleus ridge
Fixed ossicular chain
- Tympanosclerosis of drum and middle ear
- Management of malleus head or incus fixation
- Mobilisation through an atticotomy
Revision ossiculoplasty
- Challenges specific to revision surgery
- Documentation at the primary operation
- Preoperative workup before revision
- Reading the revision audiogram at 2 kHz
- Stiff system versus discontinuity
- Failure patterns after incus interposition
- Poor coupling after a synthetic prosthesis
- Consequences of an overlong prosthesis
- Posterior displacement of a TORP shaft
- Reconstruction when malleus and incus are gone
Postoperative care
- Postoperative protocol
- Indications for postoperative ventilation tube
Outcomes
- Traditional benchmarks of success
- The OOPS index
- Ossiculoplasty Outcome Parameter Staging (OOPS) index
- Ossiculoplasty Outcome Parameter Staging (OOPS) index (continued)
- Short-term hearing results
- Short-term hearing results stratified by OOPS score
- Long-term predictive value of the OOPS index
- Long-term hearing results stratified by OOPS score
- Preoperative, postoperative and final air-bone gap by risk group
- Limitations of long-term outcome studies
- Timing of ossiculoplasty failure
Complications and failure
- Classification of complications
- Minimising the risk of extrusion
- Consequences of an overlong prosthesis
- Avoiding technical failure
- Conclusions
- Numbers worth carrying into theatre
- References
- References
- References
- References
- References
- Haynes-Glasscock-Shambaugh Surgery of the Ear, Seventh Edition
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