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Canal Wall Down Mastoidectomy
Built from Haynes-Glasscock-Shambaugh Surgery of the Ear, Seventh Edition
What’s inside
8 sections · 106 slides
Concept and Historical Development
- Definition of canal wall down mastoidectomy
- Mastoidectomy in the control of otologic infection
- Radical mastoidectomy
- Remaining role of radical mastoidectomy
- Bondy modified radical mastoidectomy
- Hearing rationale of the Bondy procedure
- Tympanoplasty with canal wall down mastoidectomy
- Types of open cavity mastoid operation
Patient Selection
- Indications for canal wall down surgery
- Ear canal defect with extensive cholesteatoma on CT
- Patients unsuited to staged intact canal wall surgery
- Cholesteatoma that cannot be completely excised
- Only-hearing ear and unfavourable anatomy
- Contraindications to canal wall down surgery
- Anatomical cautions before choosing an open cavity
- Cavity maintenance and capacity for follow-up
- Patients unable to tolerate debridement
- Comorbidity and occupational factors
- Microscopic examination and audiometry
- Computed tomography before canal wall down surgery
- Role of MRI in preoperative assessment
Goals of the Operation
- Elimination of cholesteatoma
- Instrument access and the role of endoscopes
- Creation of a stable mastoid cavity
- Consequences of an unfavourable cavity to meatus ratio
- Trade-offs in cavity and meatus size
- Maximising hearing outcomes
- Paradoxical and sensorineural hearing loss
- Ossicular reconstruction options
- Hearing rehabilitation after canal wall down surgery
Setup and Operative Technique
- Preoperative briefing and patient positioning
- Skin incision and local infiltration
- Facial nerve monitoring
- Initial microscopic examination
- Canal incisions and the vascular strip
- Medial soft tissue cut and flap design
- Postauricular incision and exposure
- Preservation of the mastoid tip
- Fascia graft harvest
- Choice of graft donor site
- Periosteal flaps in canal wall down surgery
- Effect of cavity size on ventilation
- Elevation of posterior canal skin
- Sequence of the operation
Mastoidectomy and Cavity Preparation
- Bone removal and cavity planning
- Tegmen and dural safety during drilling
- Tegmen identification and control of cavity size
- Sequence of cholesteatoma dissection
- Areas prone to erosion
- Middle ear dissection principles
- Handling of the ossicular chain
- Structures worth preserving
- Removal of the posterior canal wall
- Incus removal and hearing safety
- Lowering the facial ridge
- Canal wall down cavity with the facial ridge lowered
- Consequences of a high facial ridge
- Saucerization of the mastoid bowl
- Bone pâté preparation
- Bone graft material placed in the posterior mastoid cavity
- Completing the tympanoplasty
- Ossicular graft covered by cartilage in a canal wall down cavity
- Completed tympanoplasty with canal wall down mastoidectomy
Meatoplasty
- Purpose of meatoplasty
- Common elements of meatoplasty techniques
- One-cut meatoplasty technique
- One-cut meatoplasty incision and tension vector
- Securing the meatoplasty
- Completed one-cut meatoplasty on a right ear
Adjunctive Techniques
- Rationale for mastoid obliteration
- Flaps used for obliteration
- Free grafts beneath obliteration flaps
- Limitations of non-vascularised grafts
- Materials and revision considerations
- Posterior ear canal reconstruction
- Outcomes of canal wall reconstruction
- External auditory canal closure
- Modified Rambo closure
- Safety of canal overclosure
Postoperative Care and Complications
- Immediate postoperative care
- Postoperative medication
- Follow-up schedule after surgery
- Long-term cavity maintenance
- Ototoxicity and long-term surveillance
- Complications of canal wall down surgery
- Recurrent and residual cholesteatoma
- Hearing loss after canal wall down surgery
- Mastoid cavity instability
- Caloric activation after canal wall down surgery
- Meningoencephalocele in the open cavity
- Revision canal wall down surgery
- Summary
- References
- References (continued)
- References (continued)
- References (continued)
- Haynes-Glasscock-Shambaugh Surgery of the Ear, Seventh Edition
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