The most common location of hemangiomas in the temporal bone is the geniculate ganglion (4-6) (figure 2), and the second most common location is the meatal segment of the facial nerve.
7) Although it was first assumed that the geniculate ganglion is the location of this latent viral infection, recent neuroimaging and histopathologic evidence (8,9) places the earliest enhancement (on magnetic resonance imaging [MRI]) in the fundus of the internal auditory canal (figure 3).
The mastoidectomy is performed first, and it involves a standard postauricular facial nerve decompression that extends from the stylomastoid foramen to the beginning of the geniculate ganglion.
The geniculate ganglion is located by identifying the greater petrosal nerve at the facial hiatus and following it posterolaterally with a small diamond drill and constant suction and irrigation.
4) Tumors in the geniculate ganglion
region usually lead to an intense perineural reaction or direct nerve infiltration.
At the point where the facial nerve enters the middle ear, it bends a second time at the geniculate ganglion (the second genu) and courses horizontally through the middle ear.
There are no branches, and the geniculate ganglion is not yet present (figure 5).
Polymerase chain reaction amplification of herpes simplex viral DNA from the geniculate ganglion
of a patient with Bell's palsy.
The geniculate ganglion and the labyrinthine segment of the facial nerve can be reached via both the middle fossa approach and the transmastoid approach.
The Pulec method involves tracing the greater superficial petrosal nerve to the geniculate ganglion and then exposing the labyrinthine segment of the facial nerve and the internal acoustic canal.
In 1976, the author described this condition in detail and proposed treatment by the excision of the nervus intermedius and excision of the geniculate ganglion via a middle cranial fossa approach.
Findings indicate that excision of the nervus intermedius and geniculate ganglion can continue to be performed without causing facial paralysis and that it is an effective definitive treatment for intractable geniculate neuralgia.