Temporal bone characteristics in Meniere's disease.

The petrous portion of the temporal bone in patients with Meniere's disease differs from that of healthy individuals mainly in its lack of periaqueductal pneumatization and its consequently short and narrow vestibular aqueduct. Diminished pneumatization may have an impact upon the tomographic reproducibility of the aqueduct. A total lack of periaqueductal pneumatization is prevalent in long-standing Meniere's disease. Tomography may serve as a tool by providing a basis for the choice of surgical procedure. Roentgenologic and histologic studies have indicated that the pars rugosa of the endolymphatic sac in normals mainly is housed inside the distal part of the vestibular aqueduct. In patients with Meniere's disease, the sac might be located outside the aqueduct and therefore deprived of the functions of the loose and highly vascular tissue normally surrounding it within the aqueduct. This might influence the total vascular supply of the sac, thereby interfering with its resorptive and immunodefensive functions.