Vascular mechanisms in Meniere's disease.

Normal venous drainage of the vestibular organs through the vein of the paravestibular canaliculus (PVC) may be crucial to inner ear fluid mechanics. It is proposed that increased venous pressure, with resultant venous insufficiency of the vestibular organs, may result in endolymphatic hydrops unless collateral venous circulation develops. Certain variations in pattern of venous drainage where the vestibular organs drain predominantly through the PVC vein may be a predisposing factor. In patients with Meniere's disease, different mechanisms can cause venous insufficiency. One suggested mechanism is morphologic change in the microcirculation of the intermediate portion of the endolymphatic sac. Microcirculation changes may be associated with fibrosis of the perisac tissues or shortening of the intermediate sac region or might be physiologically determined. Venous insufficiency may also result from anomalies of the PVC vein.