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Inner Ear Schwannomas
Built from Haynes-Glasscock-Shambaugh Surgery of the Ear, Seventh Edition
What’s inside
11 sections · 108 slides
Overview
- Scope of this presentation
What inner ear schwannomas are
- Definition and terminology
- Historical description
- Incidence of inner ear schwannoma
- Relative frequency against vestibular schwannoma
- Anatomy of the ear and labyrinth
Pathogenesis and patterns of spread
- Cell of origin
- Site of origin by subsite
- Cochlear duct in cross-section
- Spread within the labyrinth
- Routes of extension beyond the labyrinth
- Middle ear extension through the round window
Clinical presentation
- Demographics at diagnosis
- Frequency of hearing loss at presentation
- Patterns of hearing loss
- Misdiagnosis as Meniere disease
- Hearing loss without cochlear involvement
- Proposed mechanisms of cochlear dysfunction
- Mixed hearing loss in inner ear schwannoma
- Temporal bone correlate of footplate displacement
- Vestibular symptoms
- Vertigo with isolated cochlear tumours
- Vertigo in IES compared with IAC schwannoma
Imaging
- Role of MRI
- Classic MRI signal characteristics
- Sequences that miss small tumours
- Dedicated high-resolution sequences
- Combining T2 and post-contrast T1
- Enhancement in the vestibule and lateral canal
- Labyrinthine haemorrhage on MRI
Differential diagnosis
- Clinical differential diagnosis
- Two categories of enhancing inner ear lesion
- Labyrinthine haemorrhage
- Chronic labyrinthitis and labyrinthitis ossificans
- Imaging discriminator: tumour versus inflammation
- Rare primary labyrinthine lesions
- Lesions extending into the inner ear
Management
- Determinants of the treatment approach
- Surgical indications
- Management options
- Outcomes of an observation policy
- Symptom course during observation
- Triggers for treatment
- Middle ear extension: for and against operating
- Transtympanic gentamicin for vertigo
- Transtympanic steroid for sudden hearing loss
Surgical approaches
- Principles of approach selection
- Approach by tumour location
- Transmastoid labyrinthectomy
- Translabyrinthine approach
- The transotic approach
- Transotic resection of a cochleovestibular tumour
- Tailoring away from the transotic approach
- Transcanal and endoscopic transcanal removal
- Transmastoid facial recess approach
- Pull-through techniques deep to the modiolus
- Subtotal cochleoectomy
- Cochlear reconstruction after subtotal cochleoectomy
- Extensive cochlear tumours
- Endoscopic transpromontory removal
Outcomes and complications
- Tumour control after resection
- Vertigo outcomes after surgery
- Which vestibular symptoms respond to surgery
- Facial nerve outcomes
- Cerebrospinal fluid leak after surgery
- Observation versus surgery in younger patients
- Published radiosurgery experience
- Hearing after radiosurgery
- Indications and non-indications for radiosurgery
- Radiosurgery against microsurgery
- Current position on radiosurgery
Hearing rehabilitation
- Cochlear implantation for single-sided deafness
- Benefit of implantation over CROS
- Access and evidence for implantation
- Effect on the treatment paradigm
- Three treatment pathways with implantation
- Implantation for vestibular subsite tumours
- Intracochlear tumours as a distinct subgroup
- Limits of implantation in extensive cochlear tumours
- Results after subtotal cochleoectomy with implantation
- Implantation through an untreated tumour
- Comparing implantation strategies
- Simultaneous against delayed implantation
- MRI surveillance with an implant in place
- Labyrinthitis ossificans and the implant window
- Practical implications of ossification risk
Summary
- Diagnostic take-home points
- Management take-home points
- Conclusion
- Questions the literature has not answered
- References
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- Haynes-Glasscock-Shambaugh Surgery of the Ear, Seventh Edition
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