Resources
Glossary
The working vocabulary of perilymphatic fistula. Inline dotted terms throughout the chapter link here.
- Barotrauma
- Tissue injury from a pressure differential — here, diving, flying or a forceful Valsalva transmitting pressure to the inner-ear windows. The commonest clear precipitant of PLF.
- Beta-2 transferrin
- A marker of CSF/perilymph used to confirm a leak; less specific for perilymph than CTP but more widely available in some settings.
- Cochlear aqueduct
- A narrow channel connecting the perilymph of the scala tympani with the cerebrospinal fluid — the conduit for the explosive route of window rupture.
- Cochlin-tomoprotein (CTP)
- A protein specific to perilymph; its detection in a middle-ear lavage sample is a specific biochemical confirmation of a perilymphatic fistula.
- Exploratory tympanotomy
- Surgical elevation of the eardrum to inspect the round and oval windows for a leak and to repair it — the historical reference standard, though observer-dependent.
- Explosive route
- Window rupture from within — a surge of CSF pressure transmitted via the cochlear aqueduct to the perilymph blows the window membrane outward (Goodhill).
- Fistula test
- Applying pressure to the external canal (pneumatic otoscopy / tragal pressure) to provoke nystagmus or vertigo — a positive test supports a fistula but is insensitive and non-specific.
- Hennebert sign
- Pressure-induced vertigo or nystagmus — the basis of the fistula test; also seen in superior canal dehiscence.
- Implosive route
- Window rupture from without — a surge of middle-ear pressure (e.g. forceful Valsalva, barotrauma) pushes the window membrane inward until it tears (Goodhill).
- Mondini dysplasia
- A congenital cochlear malformation associated with perilymphatic fistula and recurrent meningitis, presenting in childhood.
- Oval window
- The window occupied by the stapes footplate. A fistula here is a recognised cause of vertigo and hearing loss after stapes surgery.
- Perilymph
- The sodium-rich fluid of the bony labyrinth surrounding the membranous labyrinth. Its loss or abnormal movement through a fistula drives the symptoms of PLF.
- Perilymphatic fistula (PLF)
- An abnormal communication between the perilymph-filled inner ear and the air-filled middle ear, usually at the round or oval window, allowing perilymph leak and abnormal pressure transmission — producing fluctuating hearing loss and vertigo.
- Pneumolabyrinth
- Air within the labyrinth on high-resolution CT — uncommon but essentially diagnostic of a fistula, as air has entered through the breach.
- Round window
- The membrane-covered window between the scala tympani and the middle ear — the most frequent site of a perilymphatic fistula.
- Tissue graft repair
- Sealing the leaking window with autologous tissue — fat, perichondrium or temporalis fascia — the definitive surgical treatment.
- Tullio phenomenon
- Sound-induced vertigo or nystagmus — present in PLF and other third-window-like states.