A perilymph fistula (PLF) is an abnormal communication between the fluid of the inner ear (perilymph) and the middle ear space. It occurs at the oval or round window membranes. The tear in the membrane can be caused by forces directed inwards (implosive) or from forces directed outwards (explosive). Common causes of PLF include blunt external trauma to the ear, barotrauma from scuba diving and rapid descent in an airplane. It can also occur as a complication after ear surgery, especially stapes surgery. Over the last fifty years some controversy existed over this condition. Whether it can occur spontaneously without any antecedent event is still debated.
Due to nonspecific features of the history and the examination the diagnosis of PLF is challenging. The common complaints of dizziness, imbalance, periodic vertigo and motion intolerance can occur with many other conditions. Patients may complain of tinnitus and aural fullness. When fluctuating hearing loss is present it can be mistaken for Menière’s disease.
The eardrum may look normal on examination. Increasing the pressure in the ear canal or asking the patient to Valsalva may induce nystagmus of the eyes and dizziness. Recording of eye movements using videonystagmography (VNG) during testing increases the sensitivity of the finding There are also other tests for PLF. Hearing tests may show hearing loss or fluctuation in hearing. Unfortunately a third of patients with PLF may not demonstrate any abnormality.
A magnetic resonance imaging (MRI) may be ordered to exclude an acoustic neuroma. Superior canal dehiscence (SCD) may mimic PLF and can be demonstrated on high resolution CT scan of the temporal bone.
Management is usually conservative and the majority of fistulae will close spontaneously. In some cases surgical exploration is indicated. If a fistula is found, sealing it will resolve the symptoms. When a PLF is suspected after stapedotomy surgical exploration may be warranted.