Applications of the marchbanks transcranial-cerebral sonography technique in neurootology: preliminary report.
[hydrocephalus with stenosis of the aqueduct of sylvius]
Transcranial-cerebral sonography (TCCS) is a noninvasive technique that allows clinicians to detect nanoliter (billionths of a liter) displacements of the tympanic membrane. This technique was developed to assess cerebrospinal fluid (CSF) pressure in cases of shunted hydrocephalus; it takes advantage of the CSF connection to the inner ear through the cochlear aqueduct. The movements of the tympanic membrane that are observed in TCCS are those evoked by the acoustic stapedius reflex and those spontaneous movements generated by intracranial arterial, venous, and respiratory pulses transmitted through the inner ear to the stapes and thence to the tympanic membrane. Analysis of the amplitude and direction of these displacements has enabled neurosurgeons and neurologists to estimate CSF pressures accurately in patients evaluated by TCCS. TCCS allows for applications in neurootology, particularly in those patients who present with symptoms of pulsating tinnitus, dizziness and imbalance, or hearing loss. This preliminary report describes the test and its application in a series of patients whose diagnoses included pulsating tinnitus, idiopathic intracranial hypertension, Ménière's disease, perilymphatic fistula, perilymphatic hypertension, arterial stenosis, and Arnold-Chiari syndrome. We conclude that TCCS is a valuable addition to the armamentarium of neurootologists.
